Imiesa April 2018

www.infrastructurene.ws

IMESA The official magazine of the Institute of Municipal Engineering of Southern Africa

infrastructure development • Maintenance • service delivery

Barloworld Equipment A value leader

Water Utilities

Trenchless Technology

Lesotho Highlands Phase II

Two world firsts at Temba

Low-volume roads

Affordable routes for Africa

IN THE HOT SEAT We have continuously ensured that transformation is engrained in our culture and our business.” Bongani Mthombeni-Möller Strategic Business Development Executive, SMEC South Africa ISSN 0257 1978

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INSIDE

volume 43 no. 04 April 2018

www.infrastructurene.ws

IMESA The official magazine of the Institute of Municipal Engineering of Southern Africa

INFRASTRUCTURE DEVELOPMENT • MAINTENANCE • SERVICE DELIVERY

Barloworld Equipment

33

A value leader

Water Utilities

WATER

LHWP Phase II

Trenchless Technology

Lesotho Highlands Phase II

Two world firsts at Temba

Low-volume roads

Affordable routes for Africa

IN THE HOT SEAT We have continuously ensured that transformation is engrained in our culture and our business.” Bongani Mthombeni-Möller Strategic Business Development Executive, SMEC South Africa ISSN 0257 1978

V o l u m e 4 3 N o . 4 • A p r i l 2 0 1 8 • R 5 0 . 0 0 ( i n c l . VAT )

The competitive price of the Cat 950 GC wheel loader takes nothing away from its reliability, fuel efficiency and the fact that this gutsy machine provides best-in-class B-pin height and dump clearance. P6

61

3 5 8 68

Technical excellence and sustainable skills development are a lifelong focus and process for SMEC and its employees. Bongani Mthombeni-Möller, strategic business development executive, SMEC South Africa, talks about the company’s transformation objectives. P10

27

SASTT Trenchless News HDD world firsts

6

Hot Seat Transformation engineered by design

10

12 15 16 20

Environmental & Geotechnical Engineering Urban drainage

24

50

Partnerships and value engineering

40

Partitions with a difference Education and bricks

42 45

Solid Waste 48

Labour-intensive Construction EPWP projects have potential

50

Transport, Logistics, Vehicles & Equipment Four pillars of excellence Locally built trucking excellence Municipal all-rounder delivers

53 57 59

Cement & Concrete

SASTT Trenchless News HDD world firsts No-Dig coming to SA in 2018

Consulting Engineering

Maximising landfill airspace

Roads & Bridges Affordable routes for Africa Leaders in bitumen Positive trend for Cape projects The ageing of bituminous binders

LHWP Phase II –

Raising the bar on development 33 A new normal 36 Creative responses to water security 38

Building Systems

Cover Story A value leader

IN THE HOT SEAT

Ride and comfort

Water

Regulars Editor’s comment President’s comment Africa round-up Index to advertisers

Cement & Concrete

27 32

Labour-intensive Construction EPWP projects have potential

Ride and comfort Testing done right

63

Cement & Concrete Testing done right

61 63

EDITOR’S COMMENT Publisher Elizabeth Shorten MANAGING EDITOR Alastair Currie SENIOR JOURNALIST Danielle Petterson JOURNALIST Liesl Frankson Head OF DESIGN Beren Bauermeister Chief SUB-EDITOR Tristan Snijders SUB-EDITOR Morgan Carter ContributorS Gavin Clunnie, Nick Mannie, Robert McCutcheon, Johan O’Connell, Wynand Steyn, Johan Van Wyk GENERAL MANAGER Candice Landie CLIENT SERVICE & Production MANAGEr Antois-Leigh Botma financial Director Andrew Lobban DISTRIBUTION MANAGER Nomsa Masina Distribution coordinator Asha Pursotham SUBSCRIPTIONS subs@3smedia.co.za Printers United Litho Johannesburg +27 (0)11 402 0571 ___________________________________________________

Where is the growth?

A

s an emerging market, South Africa remains one of the top destinations for foreign direct investment in Africa and the general sentiment is that the country presents huge opportunities.

However, the true potential will only be achieved if investors have greater certainly when it comes to policy decisions and there seems to be an improvement, given the Moody’s decision to revise South Africa’s credit outlook from negative to stable, together with a Baa3 long-term foreign and local currency debt rating. This positive change is directly linked to the new leadership structure within South Africa’s ruling party.

So, the scope for growth is definitely there, but a more open approach is still needed for most African counties. This statement is supported by the World Bank’s Doing Business 2018 statistics, where South Africa is currently placed 82nd out of 190 countries.

On the African continent, other countries in the top five are Rwanda (41st), followed by Kenya (80th), Botswana (81st), and Zambia (85th), while offshore Mauritius is 25th. At the other end of the scale, Nigeria is 145th, which is surprising considering its macroeconomic contribution.

Just to put things in perspective, when it comes to other BRICS countries, Russia, China, India and Brazil are placed 35th, 78th, 100th and 125th, respectively.

The hope is that further traction on the BRICS intercountry development goals will be achieved this year, following South Africa’s election as the new BRICS chair from January 2018. South Africa will also be hosting the 10th BRICS Summit in July 2018, which is scheduled to take place in Johannesburg.

China and India are key trading partners, accounting for 9.6% (US$8.6 billion) and 4.7% (US$4.2 billion) of South Africa’s total exports in 2017, according to World’s Top Exports.

Advertising Sales Jenny Miller Tel: +27 (0)11 467 6223 Email: jennymiller@lantic.net ___________________________________________________

Publisher: No. 9, 3rd Avenue, Rivonia 2056 PO Box 92026, Norwood 2117 Tel: +27 (0)11 233 2600 Fax: +27 (0)11 234 7274/5 www.3smedia.co.za Annual subscription: R600.00 (INCL VAT) ISSN 0257 1978 IMIESA, Inst.MUNIC. ENG. S. AFR. © Copyright 2018. All rights reserved. ___________________________________________________ IMESA CONTACTS HEAD OFFICE: Manager: Ingrid Botton P.O. Box 2190, Westville, 3630 Tel: +27 (0)31 266 3263 Fax: +27 (0)31 266 5094 Email: admin@imesa.org.za Website: www.imesa.org.za BORDER Secretary: Celeste Vosloo Tel: +27 (0)43 705 2433 Fax: +27 (0)43 743 5266 Email: celestev@buffalocity.gov.za EASTERN CAPE Secretary: Susan Canestra Tel: +27 (0)41 585 4142 ext. 7 Fax: +27 (0)41 585 1066 Email: imesaec@imesa.org.za KWAZULU-NATAL Secretary: Ingrid Botton Tel: +27 (0)31 266 3263 Fax:+27 (0)31 266 5094 Email: imesakzn@imesa.org.za NORTHERN PROVINCE Secretary: Rona Fourie Tel: +27 (0)82 742 6364 Fax: +27 (0)86 634 5644 Email: np@imesa.org.za SOUTHERN CAPE KAROO Secretary: Henrietta Olivier Tel: +27 (0)79 390 7536 Fax: +27 (0)86 629 7490 Email: imesasck@imesa.org.za

State of local construction Within South Africa’s domestic market, the latest GDP figures show a marked improvement. According to

WESTERN CAPE Secretary: Michelle Ackerman Tel: +27 (0)21 444 7114 Email: imesawc@imesa.org.za FREE STATE & NORTHERN CAPE Secretary: Wilma Van Der Walt Tel: +27 (0)83 457 4362 Fax: +27 (0)86 628 0468 Email: imesafsnc@imesa.org.za

Stats SA, Q4 reflected the highest growth rate during 2017, with the economy expanding by 3.1% quarteron-quarter (seasonally adjusted and annualised).

Agriculture surged by 37.5%, manufacturing activities rose by 4.3%, but mining and construction still remained in negative territory.

To address delivery challenges at municipal level, Dr Zweli Mkhize, Minister of Cooperative Governance and Traditional Affairs (CoGTA), is spearheading a number of initiatives. In a recent speech, he said, “CoGTA, through its implementing agent, the Municipal Infrastructure Support Agent (MISA), has decided to intervene extensively and urgently in dysfunctional municipalities and those in distress, in relation to the development and maintenance of infrastructure.” This especially applies to those municipalities that are unable to effectively spend the Municipal Infrastructure Grant (MIG) funds allocated. In the past five years, since 2012/13, municipalities failed to spend a total of R8.2 billion.

Around 7% of South Africa’s municipalities are currently classified as ‘functioning well’, while 31% are deemed ‘reasonably functional’; the remainder are in the ‘almost dysfunctional’ or ‘dysfunctional’ category.

“The situation requires the urgent deployment of MISA technical capacity experts, in the form of district technical support teams, who will provide support to municipalities towards improving service delivery,” said Mkhize.

R47.6 billion has been budgeted during the Medium Term Expenditure Framework Period for MIG projects, with R16 billion allocated for the 2017/18 financial year, spread over 226 municipalities. If government can succeed here, then it will be a welcome boon for our hard-pressed construction industry. It will also give foreign and domestic investors renewed confidence in our commitment and ability to deliver world-class infrastructure.

Alastair Currie

To our avid readers, check out what we are talking about on our website, Facebook page or follow us on Twitter and have your say. struc www.infra

IMESA

turene.ws

@infrastructure4

magazine The official of the Institute l Engineer ing of Municipa Africa of Southern

INFRAS TRUCTU

RE DEVELO

PMENT

Barloworld

All material herein IMIESA is copyright protected and may not be reproduced either in whole or in part without the prior written permission of the publisher. The views of the authors do not necessarily reflect those of the Institute of Municipal Engineering of Southern Africa or the publishers.

• SERVIC • MAINTE NANCE

Equipment

Trenchless Leso tho High

Cover opportunity

A value leader

Two worl d

Water Utilities II lands Phas e

Infrastructure News

E DELIVE RY

Technology

firsts at Temb

a

In each issue, IMIESA offers advertisers the opportunity to get to the front of the line by placing a company, product or service on the front cover of the journal. Buying this position will afford the advertiser the cover story and maximum exposure. For more information on cover bookings, contact Jenny Miller on +27 (0)11 467 6223.

roads Low -volume Afric a route s for

Affo rdab le

SEAT

engrained rmation is öller d that transfo ously ensure ni Mthombeni-M We have continu our business.” Bonga Africa SMEC South and Executive, in our culture ss Development • April 43 No.4 Strategic Busine

IN THE HOT

7 1978 ISSN 025

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President’s comment

IMESA

Innovative infrastructure solutions At this year’s IMESA conference in October 2018, we’ll be hosting our Biennial Excellence Awards and there will be a major emphasis on recognising outstanding achievements in municipal infrastructure, of which there are many great examples.

W

e’ve reduced the awards categories down to three, as we believe that this best homes in on current and future infrastructure priorities. These categories are: ‘Engineering excellence in structures and civils’, ‘Community upliftment and job creation’, and ‘Environment and climate change’.

We’re also pleased to have the South African Local Government Association (Salga) on board as an official endorser of the conference. Our partnership with Salga is a vital one in unlocking the value and accelerating the process of maintenance interventions, as well as new construction within the municipal space.

IMESA and Salga recently signed a new memorandum of understanding (MoU). The last one was concluded in 2011 and so needed refreshing. This latest MoU lays the groundwork for far more intensive interaction between IMESA and its municipal stakeholders. As a starting point, three areas of collaboration have been identified. The first one kicks off at the IMESA 2018 conference:

Salga will be delivering a presentation and will form part of our panel discussions with delegates, so it’s a great opportunity for engagement by all concerned.

The second area of collaboration is training, which we know is a top priority. The third will focus on knowledge sharing with municipalities. We are now in the process of mapping out the way forward so that we can collectively implement measureable targets to ensure successful outcomes. We’re highly optimistic that significant progress will have been made when the current MoU culminates four years from now.

Another prime example of knowledge sharing is the MoU in place with Consulting Engineers South Africa (CESA). This ties in well with our Salga agreement. Both of these organisations are instrumental in effecting the positive change we need. CESA and IMESA are also co-hosting the Biennial Excellence Awards.

No future without education Training is a central theme within IMESA, to grow and empower our members, and we are now extending this to include the broader

IMESA president Gavin Clunnie

Salga context. Experience is the best teacher and we acknowledge the need for lifelong learning, particularly in terms of on-thejob training and mentorship. The quest to transition technicians, technologists and engineers to professional registration is equally important.

Examples of current IMESA training initiatives include maintenance and GAP analysis courses under the auspices of the Municipal Infrastructure Support Agent (MISA), and water and wastewater treatment workshops now taking place in the Western Cape and KwaZulu-Natal. As part of our outreach programme, IMESA’s Western Cape branch is covering the course attendance costs for a number of young engineers based at smaller municipalities. By pooling private and public sector resources, however, a lot more can be achieved by IMESA, CESA and Salga in terms of skills development. Alongside this, we mustn’t ignore the opportunities presented by Sector Education and Training Authorities, like CETA, and the role that TVET colleges play, particularly in terms of artisan development.

Through more proactive and effective communication, and training, we can move away from short-term thinking and start refining our long-term programme planning and implementation. And that begins and ends with innovative solutions.

IMIESA April 2018

5

Cover story

A value leader Designed from the ground up to deliver a versatile loading solution, the Cat 950 GC® wheel loader is the first choice for fleet owners seeking premium performance at a competitive cost in the utility class.

T

he Cat 950 GC wheel loader is simple to operate, reliable and productive. This machine comes at a competitive price with all the advantages of its Caterpillar lineage, but without the ‘trimmings’.

What does this mean? Caterpillar recognised a gap in the wheel loader market for a lower-priced option to suit customers needing a versatile, durable utility machine with good parts availability and low fuel consumption. The 950 GC was designed from scratch using proven Cat components and technology based on years of research into customer needs. Even the frame is new.

Barloworld Equipment sold the first Cat 950 GC in Southern Africa in August 2014 and its benefits are even more appealing for customers in the current economic climate characterised by variable work opportunities and soaring costs.

Applications The 950 GC is built for applications such

as plant hire, agriculture, construction and roadbuilding, materials handling, and lightduty mining. Barloworld Equipment customers in Southern Africa who have invested in this model include quarries and mines, storage yards, asphalt plants, government departments, construction contractors and plant hire companies, among others.

“We have several Cat 950 GC units in the Barloworld Equipment Rental fleet,” says Sivu Potelwa, product specialist: Global Construction and Infrastructure, Barloworld Equipment. “This is a perfect rental unit due to its competitive purchase price, low fuel consumption, simple operation and reliability.”

She adds that Caterpillar prides itself on world-class reliability across all its products and nothing is omitted from any Cat machine that might compromise this reputation.

Performance is another priority for buyers, as well as rental customers. Complex features that might not add value for pricesensitive customers or rental users are

excluded, but the design and components in the Cat 950 GC are combined to provide levels of productivity that compete very favourably with other 5 t payload loaders on the market.

As the Cat dealer for Southern Africa, Barloworld Equipment also offers industrybeating value in terms of parts availability and technical support for the 950 GC.

950 GC vs 950L The Cat 950 GC does not replace, but rather complements the popular Cat 950L midsize wheel loader, which has an exceptional reputation for reliability, durability and performance in heavy-duty applications.

“The 950L is designed for environments that require 24-hour machine availability in tough conditions,” says Potelwa. “These customers focus more on total life-cycle costs that impact their cost per tonne. The 950 GC is better suited to customers seeking a lower acquisition cost for a machine that may work shorter shifts and will be valued according to cost per hour.”

This is a perfect rental unit due to its competitive purchase price, low fuel consumption, simple operation and reliability

COVER STORY The air-conditioned operator station features a mechanical suspension seat, straightforward hydraulic implement controls and excellent visibility

“The 950 GC is designed to be easy to operate, maintain and repair, without any compromise on performance. The machine is purpose designed to meet the needs of customers in the targeted segments using Cat legacy components that have been tried and tested for thousands of hours. The result is excellent value for money.”

Power train The Cat C7.1 engine provides a net power rating of 151 kW and meets Stage IIIA (Tier 3) emissions standards. Its new fuel injection system is specifically designed for diesel available in emerging markets. The Engine Idle Management System (EIMS) minimises fuel consumption by reducing engine rpm after a specified period of idle time.

An electronically controlled, hydraulically driven, variable-speed cooling fan adjusts to meet the var ying cooling requirements of the machine. This results in a reduced average fan speed, lowering fuel consumption, noise levels and radiator plugging.

The 950 GC’s power-shift countershaft transmission is designed and built by Caterpillar with high contact ratio gears, which means there are always up to three teeth in contact. These heat-treated gears, complemented by heavy-duty bearings, make the transmission durable and fuel efficient, also reducing noise and vibration.

Hydraulically actuated wet disc brakes are incorporated in heavy-duty axles with

The 950 GC’s Cat Performance Series bucket has a longer floor, curved side walls and wider opening

inboard planetar y final drives and specially heat-treated bevel gears.

Buckets The shape of the Cat Per formance Series buckets paired with the 950 GC has been optimised, with longer floors, cur ved side walls and wider openings.

Even less-experienced operators can achieve 110% to 115% fill factors in minimum time, speeding up cycles and saving fuel. A unique spill guard protects the cab and linkage components from material over flow.

The buckets are attached via Caterpillar’s proven Z-bar loader linkage with fabricated tilt lever to provide aggressive digging capabilities, high breakout forces, and lift and reach for a wide range of loading applications.

The 5 t wheel loader size class provides best-in-class B-pin height (4 188 mm) and dump clearance, allowing easy loading of on-highway trucks.

The loader linkage is powered by a load-sensing hydraulic system that only produces flow and pressure for the implement system when required, improving machine productivity, conser ving engine horsepower, saving fuel and reducing heat.

Service points are conveniently grouped for easy access on either side of the machine

plenty of room. The windshield is designed to maximise viewing of the work area and air conditioning is standard.

Routine ser vicing is simple and safe with ground-level access to numerous grouped maintenance and ser vice points for the hydraulic and electrical ser vice centres. Grease fittings for difficult-to-reach components are also conveniently grouped.

The Cat 950 GC comes standard with Cat Equipment Management Solutions (EMSolutions) connectivity. This gives machine owners the capability to track location, geofence machines and remotely monitor operating parameters such as hours, fuel consumption, idle time and event or fault codes. Shared with Barloworld Equipment, EMSolutions provides a power ful diagnostic and maintenance tool that guarantees maximum uptime.

“We are confident that, in the right application, customers will find the 950 GC delivers ver y competitive per formance across the spectrum of 5 t loaders, coupled with low fuel consumption and the long life for which Cat machines are renowned,” concludes Potelwa.

Operation and maintenance The Cat 950 GC cab has a cloth-covered mechanical suspension seat, low-effort pilot-operated implement controls and

www.barloworld-equipment.com

IMIESA April 2018

7

INFRASTRUCTURE NEWS

FROM AROUND THE CONTINENT

Zambia has received $2.8 million to support the development of a 34 MW peak solar PV plant

Ethiopia Power for all Ethiopia has received a US$375 million credit to support its goal of achieving universal electricity access by 2025.

Over the past decade, the Ethiopian government has launched one of the most successful electrification programmes in sub-Saharan Africa, expanding grid coverage to nearly 60% of towns and villages. Nearly 100% of this comes from renewable energy, mainly hydropower.

The Central African Backbone project will see fibre optic infrastructure enable cross-border interconnection between several countries

Ethiopia has vast and mainly untapped solar, wind and geothermal energy resources. Its National Electrification Program (NEP) requires an estimated investment of $1.5 billion over the first five years to provide one million last-mile household connections.

The financing will be used to establish new connections in line with the NEP’s three pillars: grid electrification, off-grid ser vices, and sector capacity and institutional reform. This holistic approach is intended to optimise electrification efforts to maximise the development impact of electricity ser vices,

901.8 km Gabon will install 901.8 km of fibre optic cables

irrespective of where someone happens to live.

Gabon Connecting a nation Gabon, together with partners, will undertake a feasibility study for the country’s component of the Central African Backbone (CAB) project – an integrated, innovative and transformative infrastructure project that will see the

installation of 901.8 km of fibre optic cables to cover 14 missing links on the Gabonese national backbone. The project will enhance regional integration in the Central African region through fibre optic infrastructure, enabling cross-border interconnection exchange with neighbours the Congo, Cameroon and Equatorial Guinea.

CAB is expected to open up opportunities that will integrate Gabon in the information and communications community – among other initiatives poised to close the digital divide, especially in rural areas – and empower marginal communities.

The financing of fibre optics and e-government infrastructure in Central Africa will significantly lower the cost of internet fees, considered to be the highest on the global scale, and will add competitiveness to regional exchanges while providing an important demonstration effect for new public and private

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$2.8 million

sector infrastructure projects in the region.

The total project preparation cost is US$900 000.

Nigeria Calls for a CIDB Built environment professionals in Nigeria have called for the establishment of a Nigerian Construction Industry Development Board (CIDB) to address the challenges faced by the sector.

The CIDB would be tasked with formulating, implementing and regulating policies and initiatives to speed up development processes, especially in infrastructure.

Nigeria’s construction sector faces myriad challenges, including project delays, cost overruns, poor work quality, unskilled labour, high accident rates, a lack of executive and financial capacity, payment problems and corruption.

Zambia has received $2.8 million to fund solar PV installations At an event convened by the Nigerian Institute of Quantity Surveyors, professionals from across the industry – including the Nigerian Institute of Architects, Nigerian Institution of Estate Surveyors and Valuers, Nigerian Institute of Town Planners, Nigerian Institution of Surveyors, Nigerian Institute of Building, Nigerian Society of Engineers, Commonwealth Association of Surveying and Land Economy, and heads of housing regulatory bodies – gathered to discuss these challenges and champion the call for a CIDB. Suggestions were made for a private-sector-driven agency with a board including one representative from each regulatory body in the industry.

The agency should collaborate with all arms of government

An environmental assessment is under way for the 187 km road to connect Zambia and the DRC

and promote the growth and development of construction practices, processes, projects, facilities and entities across the public and private sectors.

Zambia Boosting solar Zambia has received US$2.8 million in funding to increase its solar PV electricity generation capacity and diversify the country’s primary energy sources.

The guarantee will leverage approximately $48 million in private-sector-led investment that will support the development of a 34 MW peak solar PV power plant by Ngonye Power Company Limited. The plant will be situated in the Lusaka South Multi-Facility Economic Zone. Ngonye Power Company Limited is a JV by Enel Green Power of Italy and the Industrial Development Corporation of Zambia.

“With increased climate variability and the downward trend in capital costs, countries are increasingly looking at diversifying their primary sources of electricity generation through the addition of variable renewable energy,” said Mirlan Aldayarov, senior energy specialist, World Bank.

“The Ngonye Solar PV project provides an important example in this regard.”

Connecting nations An environmental assessment is under way for the 187 km Mwenda-Kashiba road project expected to cost US$475 million.

The project, which will connect Zambia to the DRC, will include the construction of a modern bridge across Luapula River and a border post at Kashiba.

The multimillion-dollar project is being funded through a private-public partnership that includes Groupe Européen de Développement Africa and the Development Bank of Southern Africa, and local labour will be sourced from the newly created Chipili District to help alleviate poverty levels among the area’s youth. A total of $221 million will be spent on the Zambian side, while the rest of the funds will be spent in the DRC. IMIESA April 2018

9

HOT SEAT

Technical excellence and sustainable skills development are a lifelong focus and process for SMEC and its employees. IMIESA talks to Bongani Mthombeni-Möller, Strategic Business Development Executive at SMEC South Africa, about the company’s transformation objectives.

Who is SMEC and what is your role there?

BM SMEC South Africa is a multidisciplinary engineering consulting and infrastructure advisory firm that has been delivering outstanding infrastructure solutions for over 70 years. SMEC South Africa is a progressive company that delivers engineering excellence, design innovation and advisory services to clients in South Africa and across the African continent. SMEC has established an excellent reputation for high quality, value engineering, sustainable solutions and robust innovations in all sectors of engineering.

I’m a member of our Executive Management team, which manages and oversees various aspects of our business. In business development, one of our focus areas is business sustainability and growth, as well

10

IMIESA April 2018

Transformation

engineered by design as strategy for our South African business in all markets, including Africa. As a black professional, I am proud to work for a large and progressive company that is passionate about its values: People, Professionalism, Partnerships, Purpose and Integrity.

What is your view on transformation?

SMEC South Africa supports and actively promotes government’s objectives to enhance the economic participation of black South Africans in the economy.

Transformation is not new to us – it is not a box-ticking exercise, but an ongoing process. We have continuously ensured that transformation is engrained in our culture and business.

How did SMEC reach a Level 1 BBBEE rating?

We take transformation very

seriously at SMEC. We have an in-house BBBEE committee that ensures that we comply with all the elements of the scorecard, on a continual basis. We are currently 25% black owned: the shares are held by the Kapela Disability Empowerment Concerns Trust. The beneficiaries of the trust are people with disabilities. Our black ownership will increase in the short term to exceed the requirements of the newly gazetted Construction Sector Codes (CSC). Our board composition is predominantly black, and so is our executive management team. We strive to have black representation across every tier in our organisation and pride ourselves on our technical delivery.

To ensure we stay ahead in the industry, we sharpen our tools and develop our staff’s technical knowledge and skills.

We procure services from

Bongani Mthombeni-Möller, Strategic Business Development Executive, SMEC South Africa

empowered entities and have been successful in delivering infrastructure solutions through strategic partnerships with firms that share our passion for transformation and technical excellence. We also continue to play a meaningful role in socioeconomic development.

What’s your view on the Preferential Procurement Policy

SMEC has been delivering outstanding infrastructure solutions for over 70 years.”

Framework requirement to subcontract 30% of your work?

What are some of challenges brought about by the CSC?

It is fully embraced and supported by our organisation.

Partnering with EMEs and QSEs is not new to SMEC. We’re proud to support and collaborate with a network of empowered emerging enterprises that are committed to delivering (and are able to deliver) technical excellence. This ensures that our professional teams are diverse and that the emerging firms are exposed to a number of areas in which they can develop. We want to assist companies to grow in size, to grow in their ability to tackle large projects, and to grow in their ability to stand on their own.

In that way, empowerment is measurable and meaningful.

For many years, we have had an enterprise development programme with the objectives of partnering with and empowering emerging firms.

The programme ensures that we go above and beyond what a client would require, and includes, for example, housing these companies in our offices, transferring critical skills required for the built environment, assisting them to meet the needs that are vital for the success of these smaller organisations (such as financial skills, tendering skills and cashflow), and assisting them to develop quality management systems.

According to the CSC, large enterprises are required to have a formal supplier development programme. I’m proud to be the Supplier Development Champion for SMEC South Africa.

It is my responsibility to put the programme together, select the beneficiaries and ensure that, as a collective, we address the needs of struggling firms in the built environment.

One of the things to note is the decrease in the revenue limits that define EMEs, QSEs and large enterprises. This has resulted in QSEs who earn more than R25 million being classified in the same bracket as large enterprises. This will bring about some challenges for them: they would be expected to meet the same technical and commercial requirements as their larger counterparts for certain opportunities.

What’s SMEC future outlook?

The future of SMEC South Africa looks good. We’ve been doing business for over 70 years. Last year, SMEC was recognised as the top Infrastructure Development company by the National Business Awards. We have won more than 80 industry awards for technical excellence in civil engineering, including the PMR.africa Diamond Arrow awards in both 2016 and 2017 for first overall Structural and Civil Engineers with more than 400 employees.

In a highly competitive environment with changing markets, we adapt. We continue to grow, we continue to empower and we continue to collaborate.

We want to remain a large firm so that we have the capacity to mentor and develop the industry’s smaller firms. That way, we can continue playing our part in assisting government to meet its objectives.

SMEC’s business focus areas There are five function groups (business units) within SMEC South Africa.

• Transport and Logistics: This includes all consultancy work related to roads, bridges and highways, aviation infrastructure, tunnels, ports and rail. A few of the iconic projects SMEC has worked on include: - Sanral’s Wild Coast bridges. This is classified as a national flagship project. SMEC designed the Mtentu and Msikaba bridges, and has been appointed to supervise and manage the construction of the Mtentu Bridge.

- N3 Mount Edgecombe Interchange in Durban.

SMEC was responsible for design, supervision and construction management.

• Water and Environment: This includes all consulting work related to water (potable and waste), environmental, civil infrastructure, coastal engineering and waste management.

Some of the projects SMEC has been involved in are: - Mokolo Crocodile Water Augmentation Project Phase 1 - Lesotho Highlands Water Project Phase I – SMEC is currently working on the Polihali transfer and diversion tunnels forming part of Phase II - Polokwane Wastewater Treatment works.

• Urban Development: This includes all consulting work related to buildings (architecture, mechanical and electrical, civil and structural, landscape, and project management), townships, industrial/business parks, and master planning. Some of the projects SMEC has been involved in include: - Kigali Master Plan - Richards Bay IDZ infrastructure planning - Cornubia Housing Development - Montrose mega project for Gauteng Department of Human Settlements.

• Energy and Resources: This includes mining, geotechnical engineering, oil and gas, and power. Recent projects include: - Electrification of the Royal Bafokeng Stadium - Development of the master plan for the Oil & Gas Industrial Park in Uganda - Civil, electrical and rail engineering, and project management services for the Kumba Heuningkranz Mine.

• Management Services: This includes facilities management; city, asset, development and programme management; social development; BIM services; and advisory and consulting (finance, economic and community advisory) services. Some of the projects SMEC has delivered here include: - Asset management services for the Mangaung, eThekwini and Ekurhuleni metros - Development of the KwaZulu-Natal Integrated Infrastructure Master Plan for the Office of the Premier - Programme management of the Sanitation Phase 3 infrastructure programme for eThekwini Municipality (Water and Sanitation Department), including the management of more than 60 appointed service providers and the provision of cost control services for the roll-out of public ablution facilities to informal settlements; this was an EPWP project - Programme management of the Zibambele Poverty Alleviation Programme, which involves the administration and monitoring of 6 000 beneficiaries, many of whom come from women-led households, who partake in routine road maintenance; SMEC developed the system for this purpose.

www.smec.com

IMIESA April 2018

11

Roads & Bridges

Affordable

routes for Africa Low-volume roads (LVRs) serve as the backbone of rural economies and are among the most affordable ways to link communities and markets, according to Dr Estimé Mukandila, technical director, iX engineers.

By Alastair Currie

C

urrently, more than 70% of South Africa’s approximately 747 014 km road network is unsurfaced. Compare that to Nigeria, one of Africa’s other leading counties, where the figure is around 85%, but based on a much lower overall network of some 193 200 km.

So in African terms, South Africa’s overall road system is by far the largest on the continent. It’s also the most advanced. However, how well is it being maintained? According to the South African Institution of Civil Engineering’s (SAICE’s) third Infrastructure Report Card, released in Q3 2017, the answer for gravel roads is “not very well”. In fact, gravel roads received the lowest score on an A to E scale – A being world-class, and E being unfit for purpose.

“It should be noted that the maintenance funds allocated to rural roads in most African countries is highly insufficient, covering only 5% to 15% of the maintenance requirements,” Mukandila points out.

“That would also explain the

reason for the E grading for South Africa’s gravel roads in terms of the SAICE findings.

“So if you consider the current situation in South Africa, just imagine the challenges in the rest of Africa, where access to funding, engineering resources and specialist construction equipment are thin on the ground,” says Mukandila.

Within the developed and developing world, one of the most effective and affordable solutions for less-trafficked routes is the provision of well-made and sustainable LVRs, which can be gravelled or surfaced. The latter includes single and double seals, cold mix asphalt, concrete block paving, cobble stones, and concrete surfacing. However, most LVRs are gravel routes.

By definition, LVRs are transportation systems typically constructed from locally available resources and are predominantly located in rural or undeveloped areas. They usually accommodate low traffic volumes of up to about 300 vehicles per day and less than about 1.0 MESA (million equivalent standard axles), but generally less than 0.5 MESA. LVRs also usually cater for

Measures such as improving drainage to minimise the possible presence of water in the pavement structure should take precedence.”

Dr Estimé Mukandila, technical director, iX engineers

12

IMIESA April 2018

potentially extreme axle loads from vehicles like trucks and buses.

LVR features Key characteristic of LVRs include the following: - They are designed for access rather than mobility (with a limited speed limit of around 80 km/h).

- They follow the existing geometric alignment of the road but, where black spots exist, such as blind crests, necessary measures should be taken to minimise the risk of accidents.

- They use locally available materials, unlike high-trafficked roads that generally require specific engineered materials for the upper pavement layers. Locally available materials are generally moisture sensitive and so the design needs to take this into account.

“Since construction materials are seldom imported, engineers need to ask the question: ‘What is the appropriate road I can build with the available materials?’ Instead, they usually ask:‘Where can I find materials to meet the specifications?’ That’s a major mindset shift for most consulting engineers, who still base their designs for LVRs using commercially sourced aggregates and California bearing ratio tests,” says Mukandila.

Upgrades If well constructed and well maintained, an LVR should last for the designed period. One method for determining the existing condition

DCP

OR 31

SATCC

TRH 4

Bituminous surfacing

Surface dressing

50 hot mix asphalt

Bituminous surfacing

150 natural gravel, soaked CBR >50% @ 98% MDD, PI<16 In situ soil (original surface)

200 crushed or natural gravel (GB1-GB3), soaked CBR >80%, PI<6 200 granular sub-base (GS) In situ soil (original surface)

175 Crushed or natural gravel, soaked CBR >80% 175 natural gravel, soaked CBR >30% In situ soil (original surface)

A comparison between the different road surfacing options available, starting with an LVR scenario (far left) and extending up to a world-class flexible pavement structure (far right)

is the use of dynamic cone penetrometer (DCP) testing. This test forms part of the DCPDN design method.

DN, which is the weighted average penetration rate of the cone (mm/blow), represents the strength of pavement materials. The DCPDN method can be used as a design tool and also for quality control during the construction stage to ensure layer strength requirements are met.

The aim of the DCP-DN method is to achieve a balanced pavement design that makes optimal use of the existing material strength from many years of traffic compaction and moulding. The main emphasis is to use the existing road pavement structure without disturbing its inherent strength and only adding material of the required quality and thickness to carry the anticipated traffic design loading.

Money saved here can then potentially be used to seal the road. Benefits of sealing include more effective weather sealing, better riding quality, reduced health hazards (dust pollution), and a possible increase of the road’s lifespan.

The selection of the type of seal is influenced by a number of factors. These include material availability (such as aggregates, binders, and cement), the topography of the terrain, climate of the area, local experience with the type of seal, and expected durability and life-cycle costing. Budget availability for maintenance is also a major consideration.

“The environmentally optimised design principle is a key concept ensuring that every section of road is treated according to its specific environmental condition,” he explains. “For example, no additional layers on flat, strong sections; concrete surfacing on very steep grades; and adequate pavement structure and drainable in marshy zones.”

“Most consulting firms in the roads industry focus on high-trafficked roads,” says Mukandila. “However, at iX engineers, we specialise in the former and LVRs, which, in my view, is more challenging from a materials and drainage perspective.”

Stabilisation methods can be considered for LVR. However, Mukandila points out that this should only be employed as a last resort.

“The DCP-DN method is not a ‘magic solution’, but we believe it will, thanks to its cost-effectiveness, be part of the solution in contributing to South Africa’s and Africa’s low-volume road requirements.”

125 crushed or natural gravel, CBR >80% soaked @ 98% MDD, PI<6 125 natural gravel, CBR >30% soaked @ 95% MDD, PI<12 150 compacted gravel/soil, CBR >15% soaked @ 93% MDD, PI<6 In situ soil (original surface)

“Measures such as improving drainage to minimise the possible presence of water in the pavement structure should take precedence,” he asserts.

Training and skills transfer The company’s LVR project experience in Africa is extensive and, in addition to South Africa, includes Malawi, Ghana, Sierra Leone, Liberia, the DRC and Tanzania. “We are also involved in knowledge transfer in these countries through training and demonstration sessions, as well as through the presentation of papers at international conferences,” he explains.

Another key benefit of LVRs is that they are ideally suited for labour-intensive construction programmes, creating employment and skills development across Africa in the process.

“The DCP-DN method is not a ‘magic solution’, but we believe it will, thanks to its cost-effectiveness, be part of the solution in contributing to South Africa’s and Africa’s LVR requirements. LVRs shouldn’t be neglected because they empower rural communities and help eradicate poverty. Therefore, more focus should be given to LVRs, supported by ongoing training in design and construction. On the surface, LVRs seem simple to construct, but actually require a great deal of engineering experience,” Mukandila concludes.

IMIESA April 2018

13

cing

urfa

ro-S

Mic

Leaders in bitumen

Roads & Bridges

Tosas prides itself on constant innovation, keeping abreast of the latest technological developments and continuously researching new products. IMIESA speaks to Werner Tessendorf, Business Development Manager, Tosas, about the progress of some of the company’s leading products.

Since we last spoke, more NCRT™ volumes have been secured and product supplied. Can you tell us more about this?

WT We are very happy and excited to say that we have now literally crossed borders with our product – all the way from South Africa into the northern parts of neighbouring Namibia.

With the sometimes expected cross-border hiccups that can occur, NCRT has been put to the ultimate test. Border delays resulted in the first load being held up for an extended period, which resulted in the load being pushed beyond what we deem to be reasonable time frames. However, when it finally arrived on-site, the product was perfectly within specification and could be applied with no problems whatsoever. This supply of NCRT to the Namibian Roads reseal contract in the north of Namibia (between Oshivelo and Omuthiya) will certainly go down in the history books as a massive game changer in the area of bitumen rubber.

Supplying NCRT from Wadeville in Johannesburg obviated the need for the very costly establishment of a rubber blending plant on-site (or in the country for that matter), and blending under very good- quality systems in a

factory has also added quality assurance benefits. Transportation of rubber bitumen binder over a distance of more than 1 800 km to site, through Botswana and into Namibia, would never have been considered or possible prior to the introduction of NCRT. The use of this technology for the mitigation of risks and the flexibility to adapt to programme changes arising from weather conditions and other delays has, once again, been thoroughly proven in this application of NCRT. We believe that the opportunities this brings about for both large- and small-volume contracts will be of massive benefit to roads authorities in countries outside South Africa, as the normal impracticalities and high costs of cross-border rubber blending plants are completely negated.

On the local front, the product also continues to gain traction.

We are supplying NCRT to a contract at Ga-Seleka village near Lephalale, where the use of conventional rubber bitumen would have required multiple site establishments for a rubber blending plant, or at the very least for the team, which would have been too costly and not feasible.

How is your Ralumac® product progressing?

Tosas is the proud licence holder of this original technology

and we are very excited that we are able to reintroduce this great technology for the roads authorities in South and Southern Africa. The name carries historic successes and we are happy to see the excitement that prevails around the product and its reintroduction into the local roads maintenance space.

We have just completed a very successful Ralumac rut filling contract on the N2 between Mossel Bay and Great Brak River.

This contract followed the equally successful completion of a similar rut filling contract on the N1 between Dwyka and Weltevrede (Prince Albert), and we look forward to many more such projects.

What are the benefits of Ralumac?

Ralumac provides solutions to deal with problems like distortions and deformation due to traffic, and can restore and re-profile ruts up to 75 mm deep. The increasing demand on bitumen for our road infrastructure by modern-day traffic has led to challenges that are common to all classes of roads, wheel track, rutting, fretting at the edge and surface deformation, and Ralumac provides an excellent and cost-effective solution.

Ralumac is designed and specifically formulated with polymer-modified bitumen emulsion, high-quality aggregates

and an experienced labour force, while the Tosas application is done using a crew with many years of application experience.

One of the most difficult problems engineers face in their maintenance programmes is fattening up due to excess bitumen on all classes of roads.

Ralumac is specially designed to reduce the effect of excess bitumen, filling ruts, depressions and plucks before receiving the new top wearing coat (or seal), thus giving an excellent riding surface with good texture.

Ralumac can also be used as an overlay or new surfacing for both roads and airport runways, depending on traffic conditions.

Ralumac offers several advantages: • fills ruts, can be applied at varying thicknesses • restores texture, improves skid resistance • cures quickly for early traffic return (20 to 60 minutes) • night- or daytime application • ultrathin for maintaining overhead clearances, curb reveal and drainage • delineates pavement markings and shoulders • environmentally friendly cold process • cost-effective preventive maintenance seals and protects pavements • can be used 365 days a year, depending on precipitation.

Werner Tessendorf, Business Development Manager, Tosas

IMIESA April 2018

15

Roads & Bridges

Positive trend for Cape projects

Sustainable supply channels developed by Much Asphalt, coupled with multistage bitumen converter technology, support road infrastructure programmes under way in the Eastern and Western Cape provinces.

M

uch Asphalt is seeing a slight upward trend in road infrastructure projects in the Cape region in 2018, resulting in improved orders received by its plants in Port Elizabeth, George, Eerste River and Contermanskloof.

“Our workload has increased slightly overall compared to this time last year,” says Dave Bullock, regional manager, Much Asphalt, adding that orders are coming in from national, regional and local government departments.

“There are more large projects on the way for Sanral, particularly on the N2 freeway, but these will only affect volumes in Much Asphalt’s next financial year – from July 2018.”

Bullock says a reduction in road infrastructure development and maintenance projects over the past few years has impacted the asphalt sector. This has been exacerbated by high credit risks and poor payment, as the construction sector has battled the slow economy. However, Much Asphalt remains

16

IMIESA April 2018

the biggest producer in the Western Cape and Bullock believes the firm’s 51 years of product knowledge and technical expertise put it ahead of the competition. “The fact that we have two plants in greater Cape Town – at Eerste River and Contermanskloof – also gives our customers the reassurance of consistent supply,” he adds.

Bitumen Much Asphalt is sourcing most of the 50/70 penetration grade bitumen commonly required in asphalt mixes from a subsidiary, SprayPave. In 2016, SprayPave acquired unique technology to provide Much Asphalt and other producers with the bitumen quality required for the sustainable supply of high-specification asphalt.

This capability is provided by a multistage bitumen converter from Technix Industries in New Zealand, which changes conventionally available refinery penetration grade bitumen to grades that suit the asphalt specifications required by the roadbuilding sector.

Paving of NCRT warm mix asphalt on Clarence Drive between Gordon’s Bay and Rooi-Els (Photo credit: Deon Ferreira, Much Asphalt)

This technology is particularly important in the Western Cape, which does not have any immediate access to the bitumen grades required to produce high-quality asphalt.

Now these grades can be produced simply by inputting the 70/100 penetration bitumen supplied by Chevron and converting it to SABSapproved 50/70 or whatever is required.

In addition to offering clients a solution to several years of bitumen shortages, Bullock says Much Asphalt is placing specific focus on communicating with the Cape regional clientele to discuss requirements with a view to improving service delivery and product quality.

Current projects Meanwhile, Much Asphalt is supplying several large road infrastructure projects across the

Roads & Bridges

Paving of bitumen rubber asphalt base (28 mm Colto BTB with AR-1) to fast and slow lanes of Durbanville Avenue (Photo credit: Deon Ferreira, Much Asphalt)

region. The Port Elizabeth plant was awarded the asphalt supply contract by Concor Infrastructure for the rehabilitation of the R75 between Port Elizabeth and Despatch for Sanral.

In turn, the George plant has recently won a contract to supply asphalt requirements for all depots of the George Municipality over a three-year period. In February 2018, this plant also started producing asphalt for a Roadmac Surfacing project on the N2 between Mossel Bay and Groot Brak.

In Cape Town, Much Asphalt Eerste River will start work in April supplying Roadmac’s Sanral maintenance contract between the Baden Powell and Broadway Boulevard interchanges on the N2 freeway.

In a project on Clarence Drive between Rooi-Els and Gordon’s Bay for the Western Cape government, Much Asphalt is supplying NCRT (new crumb rubber technology) premix to Roadmac.

Further afield on the N2, asphalt is being hauled 180 km from the Eerste River plant for a reseal project between Swellendam and Riviersonderend.

Roadmac is the contractor. The same branch has also just successfully completed delivery to Martin and East for the Strandfontein (M23) project between Govan Mbeki and Spine roads over 24 months.

The Contermanskloof plant continues to service the West Coast region and is currently supplying three Haw and Ingles contracts on the N7 freeway. These include sections between Voortrekker Road and Hopefield, Leliefontein and Abbotsdale, and Atlantis South and Kalbaskraal.

The high-profile N1 rehabilitation contract under way by Martin and East in Cape Town’s northern suburbs is also being supplied by Much Asphalt from Contermanskloof. This fouryear project requires product to be delivered to a very busy section of the N1.

QUALITY

ACCOUNTABLE FOR QUALITY Much Asphalt is southern Africa’s largest manufacturer of hot and cold asphalt products.

We don’t just promise quality. We hold ourselves accountable for it. Process control laboratories at every plant and on site continually monitor and test our processes and products. Our customers can rest assured they are placing and compacting quality asphalt.

17 static plants • 5 mobile plants • extensive product range • stringent quality control • bitumen storage • industry training

T: +27 21 900 4400 F: +27 21 900 4468 E: info@muchasphalt.com www.muchasphalt.com

IMIESA April 2018

17

Roads & Bridges | Technical Paper

The ageing of bituminous binders

By Johan O’Connell and Wynand Steyn*

T

he stiffness of an asphalt layer has a critical influence on its per formance and is affected by temperature and time as the bituminous component of the asphalt layer ages. As the stiffness increases with ageing, the traffic loads on the sur face will be distributed differently throughout the pavement in accordance with multilayer linear elastic theor y.

As asphalt ages and stif fens, the potential for failure in the form of cracking or ravelling becomes increasingly likely.

A better understanding of the ageing of asphalt mixes can aid the development of technologies, processes and specifications that can lead to a reduction in agerelated cracking.

Bituminous binder is subject to a number of well-documented mechanisms of ageing, which can be monitored by bituminous binders’ physical or chemical proper ties.

Figure 1 The dynamic shear rheometer at the CSIR

20

IMIESA April 2018

Atomic Force Microscope (AFM) Images of bitumen No ageing

1 h ageing @ 40°C

1 h ageing @ 80°C

1 h ageing @ 140°C

40/50 Pen

60/70 Pen

100/120 Pen

150/200 Pen

The physical proper ties are described by tests such as: • penetration • softening point • absolute viscosity • kinematic viscosity • a pparent viscosity by rotational viscometer • Fraass breaking point • ductility • c omplex modulus (G*) and phase angle (δ).

The rate and extent of ageing of bituminous binder can also be monitored using the following physicochemical and chemically based methods: • infrared analysis • atomic force microscopy (Figure 2)

Figure 2 Ageing study of bitumen using AFM

• elemental analysis • gel permeation chromatography or sizeexclusion chromatography • thermal analysis • SARA (saturates, aromatics, resins and asphaltenes) (Figure 3).

During ageing, the saturates remain largely unchanged, but there is a general conversion from aromatics to resins and from resins to asphaltenes. By monitoring these changes, the rate and extent of ageing can be monitored.

Instead of monitoring the rate of ageing using the bituminous binder, some

Roads & Bridges | Technical Paper

researchers monitor the asphalt mix directly during ageing studies. Asphalt mix tests may include physical tests such as indirect tensile strength, dynamic modulus or even Cantabro.

Ageing trends determined by empirical tests (penetration, softening point, Fraas, etc.) can provide different results than those found using rheological parameters generated by the dynamic shear rheometer.

This is most relevant for polymer-modified binders, and indicates that empirical proper ties such as penetration, softening point and ductility are limited in scope with regard to their determination of the intrinsic rheological proper ties of such bituminous binders. During the execution of these empirical tests, strain rates and stress are variable and unmeasurable, making the interpretation of the results problematic.

Figure 3 The developing tank and interpretation of TLC spots

and long-term ageing (LTA). STA represents the ageing that an asphalt mix undergoes during manufacture, storage, transpor t and placement, while LTA represents the ageing after placement, and over the lifetime of the pavement.

Stages of ageing

Short-term ageing

During the lifetime of an asphalt layer, the ageing of the binder can be divided into two distinct phases: shor t-term ageing (STA)

STA is a high-temperature process, which favours high-energy oxidation mechanisms and volatilisation. The high rate of ageing that

Fractions

UV colour

saturates

blue

monoaromatics

grey yellow

diaromatics

dark grey

polyaromatics

dark

resins

dark

occurs during high temperatures requires upper limits to be placed on the mixing temperatures and the time that asphalt mixes spend at these temperatures.

For binder specification purposes, a test is required to simulate the ageing a binder undergoes during STA. South Africa prescribes the most prevalent test internationally – the Rolling Thin Film Oven Test (RTFOT) (ASTM D 2872, 2012). During this test, bitumen rotates in a moving thin film in a glass bottle in a forced draft oven at 163°C for 85 minutes. Developed by the State of California Depar tment of Public Works in 1963, it gave a relatively

Roads & Bridges | Technical Paper

Figure 4 The PAV ageing oven at the CSIR

good indication of ageing for a 50/70 penetration type binder used in dense, continuously graded mixes for that place and time.

Other well-established STA methods include the Thin Film Oven Method (ASTM D1754, 2014) and the Rotating Cylinder Ageing Test (RCAT) (EN 15323, 2007).

A major disadvantage all of these tests, including RTFOT, have in common is that they are not pressurised. The rate of oxidation is dependent on the par tial pressure of oxygen and is, therefore, altitude dependent, resulting in variations in results from different laboratories.

A pressurised test would eliminate such variation.

The validity of RTFOT simulation for South African conditions needs to be investigated, considering the wide

range of mixes ranging from warm mix to SBS-modified binders and the large variations in mixing temperatures and hauling distances.

STA can also be carried out on an asphalt mix in the laborator y. One protocol is the Superpave STA procedure. The method consists of placing the prepared mix back into the oven and leaving it there for four hours at 135°C before compaction. A slight adjustment to this method has been made as par t of the CSIR test protocol development, whereby the mix is aged at the compaction temperature for that mix.

Long-term ageing With regard to correlation with laborator y ageing, especially for specification purposes, LTA can be defined as the ageing a pavement layer undergoes during a period of five to ten years after placement.

LTA is a medium-temperature process ranging between -5°C and 70°C in South Africa. It would favour lower-energy

Figure 5 Graphical representation of STA and LTAR

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IMIESA April 2018

oxidation mechanisms and volatilisation would not be a major factor, unless the bituminous binder has been cut back with solvents or oils.

For bituminous binder specification purposes, a test is required to simulate the ageing a binder undergoes during this LTA process, representing a period of five to ten years, depending on the climate in which the mix is placed, the latitude and the mix proper ties. The most popular test is the Pressure Ageing Vessel (PAV) test (ASTM D 6521). During the PAV test, a thin film (3.2 mm) of bitumen taken from the RTFOT is placed in a pressurised oven (2.1 kPa, 90°C to 110°C) for 20 hours (Figure 4).

There is much debate as to what the results of the PAV ageing represents and little work has been done for South African mixes to date. The PAV test ageing conditions are considered by some to be more severe than field ageing after five to ten years of binder in relatively thick asphalt layers, whereas others have an opposing point of view.

An impor tant point to note is that the laydown viscosity for mixes often exceed RTFOT viscosity by a substantial margin. It gives field ageing an unfair disadvantage in that it star ted at an “advanced stage” of ageing. It may well be that PAV ageing could simulate five to ten years of field ageing if the star ting point, i.e. RTFOT ageing and lay-down ageing, were at approximately the same state of ageing.

It is interesting to note that when the comparisons were made using the bending beam rheometer (BBR) stiffness as opposed to viscosity or G*/sin δ, none of the binders come close to approaching the PAV stiffness. This confirms that the oxidative ageing mechanism in the PAV chamber differs from that taking place in nature.

There are other LTA methods but none are well established. All accelerated ageing

Roads & Bridges | Technical Paper

methods should be based on simulations that strive to yield residues with properties similar to binders after defined periods of in-situ field ageing. Some have proposed that laboratory tests to simulate in-service ageing should be conducted at temperatures below 100°C (between 70°C and 95°C is advised) since, at higher temperatures, the reaction mechanism differs from that occurring in the field.

Work done on the RCAT to simulate the PAV has been done. The weatherometer – which involves cyclical exposure to UV light, moisture and heating conditions – is also increasingly being researched as a method to simulate LTA. Protocols have been developed for the LTA of asphalt mix in the laborator y. To simulate the ageing of the mix over a period of five to ten years, the LTA procedure is commonly used. After compaction, specimens made from the STA mix are put back into the oven and aged for five days at a temperature of 85°C. Asphalt briquettes can also be stored in a forced draught oven for six days at a temperature

of 80°C (Superpave LTA procedure), which supposedly simulates five to eight years’ in-ser vice ageing.

Conclusion It has long been the goal of researchers to find rapid methods to simulate the ageing of asphalt pavements but, at the same time, maintain the identical ageing mechanisms experienced in the field. In this way, all the proper ties of the binder can be simulated over the entire temperature range experienced by the binder in the asphalt layer. This is an unattainable goal, as the ver y act of simulation implies a shor ter time, which necessitates or drives a change in ageing mechanisms.

At best, we can aim for ageing methods that roughly simulate ageing to give comparable proper ties for the simulated binder and field binder at high and low temperatures, which can be used for specification purposes. It is impor tant to understand the limitations of ageing methods, and how these af fect the correlation between laborator y and field

Full paper: This paper is a summarised version of a paper presented at the 2017 Southern African Transport Conference.

To view the full version, visit www.satc.org.za or scan the QR code

binders. In this way, we can appreciate the impor tance of having realistic fatigue specifications for binders, while realising that there are many other factors controlling and contributing to the ageing rate of an asphalt layer. *Johan O’Connell is a senior researcher in the CSIR’s Transpor t Infrastructure Engineering Group and Wynand Steyn is the head of the Civil Engineering Depar tment and an associate professor at the University of Pretoria.

Environmental & Geotechnical Engineering

Urban drainage

R

apid urban growth in South minimising the problem of run-off. Importantly, Africa has created an for drought-prone South Africa, by infiltrating unprecedented increase the ground naturally, this rainwater replenishes in hard sur face areas. groundwater and aquifers.

As a result, conventional stormwater Environmentally sound, Sudpave ensures infrastructure can no longer cope with the pollutants such as car oil and brake dust resultant high level of rainwater run-off, are not conveyed by run-off into streams and which, in extreme conditions, often leads to rivers, but are filtered out and broken down by severe flooding. The quest by municipalities natural microbial action. for alternative methods Produced from of stormwater control locally sourced Produced from led to the development recycled material locally sourced of Sudpave â&#x20AC;&#x201C; a unique, and resources, permeable paving system recycled material and Sudpave is non-toxic supplied locally by sole resources, Sudpave is and chemically inert distributor Kaytech. non-toxic and chemically to the chemicals Complying with naturally found in the requirements of inert to the chemicals soils. It is suitable sustainable urban drainage naturally found in soils.â&#x20AC;? for a wide variety systems (SUDS), Sudpave of applications is a plastic grid paver with an open-cell including car parks, emergency access routes, structure, either gravel-filled or grass-planted wheelchair access, aircraft taxiways, helipads depending on load-bearing requirements. and equestrian arenas.

Rain is able to soak through the permeable Recent projects include the Walmer Prepaved area at the point of contact, thereby Primary School in Port Elizabeth, where a

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IMIESA April 2018

grassed verge served as the daily drop-off and pick-up zone for young learners. A problem occurred on rainy days when the sparsely grassed trafficked areas became water-logged, muddy and difficult to negotiate. Instead of replacing the aesthetically pleasing natural verge, 600 m2 of Sudpave was installed, creating a combination of gravel driveway and grassed verge parking. This proved to be a highly successful and economical project, satisfying all stakeholders.

Key benefits Installing Sudpave delivers many benefits, some of which include: accelerated installation, with no pinning required excepting excessive gradients; suitability for hot and cold climates due to its expansion and contraction capabilities; less wastage, as pavers can be incrementally offset and connected to accommodate curves and obstructions; as well as reduced incidence of flooding.

In addition, Sudpave can also be used in conjunction with a water recycling system as a catchment source.

s

e l s h sN c n e e w r T

A world of HDD firsts

31

No-Dig coming to SA in 2018

36

www.sastt.org.za

ISTT’s 36th Annual International No-Dig Conference and Exhibition, hosted by the Southern African Society for Trenchless Technology (SASTT)

8-9 October 2018 Cape Town International Convention Centre (CTICC), South Africa

Call for papers now open!

Deadline: 4 May 2018

Prospective authors are invited to submit proposals for consideration in the conference programme. Please visit www.nodigsouthafrica.com

International Exhibition and Conference featuring: • • • •

Trenchless Technology Underground Infrastructure Underground Utilities Pipeline Technologies

Take part in South Africa’s only specialist showcase of trenchless technology, combined with Cape Town’s host of tours – this is one not to be missed.

Limited stands available – Book your space today!

Contact Paul Harwood – pharwood@westrade.co.uk or telephone +44 (0)1923 723990

www.nodigsouthafrica.com

36th International NO-DIG

International Society For Trenchless Technology

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Organised by

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SASTT Trenchless News

A world of HDD firsts An innovative horizontal directional drilling (HDD) project that succeeded in producing two world firsts has won the 2017 Joop van Wamelen SASTT Award of Excellence.

The Joop van Wamelen SASTT Award of Excellence is handed out annually by the Southern African Society for Trenchless Technology in recognition of exceptional contributions to the active promotion and implementation of trenchless technology in Southern Africa

T

he Temba Water Purification Plant in Hammanskraal is being upgraded to deliver water to thousands of residents in areas north of Pretoria. The upgrade will provide for additional on-site storage and included the replacement of an existing raw water pipeline.

A 1 300 m section of 800 NB asbestos cement (AC) pipe required replacement underneath wooden electrical pylons and cables, which were to remain operational during the replacement works, prohibiting the use of large conventional construction equipment. Thus, a trenchless solution was sought.

Specialist contractor Trenchless Technologies explored a range of trenchless replacement and lining technologies, and pipe reaming proved to offer the most economical solution.

Although pipe reaming is a pipe replacement methodology similar to pipe bursting, it offers some unique advantages, explains Marco Camarda, general manager, Trenchless Technologies. â&#x20AC;&#x153;Pipe reaming allows for extremely large upsizing of 100% and more, which is not available with displacement-type pipe bursting techniques, whether static or percussive, particularly at shallow depths.

As such, pipe reaming can be a useful tool

ABOVE A DD10 American Auger HDD rig was utilised to undertake the pipe reaming works

RIGHT The drill rods are connected to a stabiliser and a sheilded pipe reamer, which is in turn connected via a swivel to a bull-nose. The bull-nose is attached to the new 800 PE 100 PN 16 pipe

Project Description Client: City of Tshwane Specialist subcontractor: Trenchless Technologies cc Engineers: Aecom Contract duration: 26 weeks Contract value: R14 million Length: 1 300 m Existing pipe: 800 NB AC (wall thickness 47 mm) New pipe: 800 HDPE PE 100 PN 16 (wall thickness 76 mm)

IMIESA April 2018

27

SASTT Trenchless News

Challenges to overcome included: Air Valves Unidentified underground air valves were found

Steel Joints Steel joints and couplings had to be removed

Transformer The mini-sub removed by Eskom required additional supporting

to expand the capacity of urban sewers and water pipes in dense urban areas.”

thickness of 76 mm, supplied by Marley Pipe Systems.

This marked the first of what is believed to be two world firsts on this challenging project – the largest-diameter host pipe known to have been replaced by pipe reaming technology.

To achieve this, a DD10 American Auger HDD rig capable of pullback forces of 50 t and a rotation force of 18 982 Nm, was utilised, explains Camarda.

The rig’s 6.1 m long drill rods are threaded together by the HDD rig to form a long continuous drill stem and pushed from

One for the history books The existing 800 NB AC pipeline was reamed out and replaced with a new 800 mm OD PN 16 HDPE pipe, with a wall

WINNER SASTT AWARD OF EXCELLENCE 2017 FOR WORLD-FIRST PIPE REAMING IN TSHWANE

25

YEARS

Pipe Bursting • Sliplining • CIPP UV Cure • CIPP Ambient Cure Ribloc Expanda • Ribloc Ribline • Ribloc Rotoloc • Pipe Reaming Horizontal Directional Drilling • Guided Rock Drilling • Bores of 1400mm Lengths up to 1000 metres • Microtunnelling • Pipe Ramming

www.trenchless.co.za +27 (0)86 006 6344 info@trenchless.co.za

SASTT Award of Excellence 2007, 2009, 2015 & 2017

SASTT Trenchless News

the HDD rig through a receiving pit into the existing AC pipe up to the launch pit. The drill rods are then connected to a stabiliser and a pipe reamer with an extended shield, which is in turn connected via a swivel to a bull-nose.

The bull-nose is attached to the new 800 mm PE 100 PN 16 pipe.

In order to reduce the number of buttwelds required, the pipe was delivered to site in 18 m lengths. These lengths were butt-welded into long continuous sections of approximately 150 m to be pulled into position in the reamed-out bore behind the reaming assembly.

The existing AC pipe was cut into smaller fragments, mixing the pipe cuttings into the surrounding soil and into the inflowing bentonite mud mix. The mixture of bentonite and water helps to maintain the integrity of the bore, and lubricates and surrounds the new HDPE pipe during pull-in.

This brings us to the second world first – undertaking the pipe reaming and installation of the 800 HDPE pipe in a single pass, without first filling the host pipe void with bentonite and then reaming in stages to insert the HDPE pipe.

Electrofusion couplings Connection between the 150 m lengths of installed HDPE was achieved by means of electrofusion couplings imported from Germany. According to Camarda, the process involved pre-warming the actual pipe through the coupling before welding, which proved to be extremely successful. Air valve systems were also connected by means of electrofusion saddles, vacuum-held and strapped, to provide a complete HDPE solution.

End-point and scour-valve connections were achieved by HDPE stub-ends and backing flanges. The advantage of this, says Camarda, is being able to position exactly where the highest points are. Only six stub-ends and backing flanges were used on the project.

Pulling A1 welded pipe into the launch pit

Pipe in 18 m lengths

BELOW A lining of 250 µm plastic sheeting was used to to contain the bentonite, spoil, asbestos and water

ABOVE A Kosun KSMR-250 mud separation system was used for removing the contaminated asbestos elements

Features and benefits of HDPE pipe Marley Pipe Systems’ Megatuff HDPE pipes were used on the project. Benefits include: • High impact strength: The high impact strength compared with other plastic materials ensures a greater resistance to the rigours of pipe laying conditions • Damage resistance: Low notch sensitivity provides a high level of resistance to the effects of external damage, which is especially important for pipe bursting operations and other applications where there is a likelihood of such damage • Ease of installation: Being lightweight and having long lengths, polyethylene coiled pipes are widely used in applications such as stock watering, irrigation systems, communication, gas and reticulated water mains due to rapid installation and the ease and low frequency of jointing • High flow capacity: With lower friction factors than most non-plastic materials, the surface energy characteristics of HDPE ensure that material deposition is inhibited, and the smooth bore characteristic is maintained over the working life of the pipeline • Long life: Possessing a proven high reliability record across a wide range of industries and applications for a period of nearly 50 years, HDPE also provides a long maintenance-free lifetime with low whole-life costs compared to many other materials • Trenchless construction: With features such as long lengths, corrosion resistance, light weight and ease of installation with minimal disruption, the pipes offer many advantages in slip lining, pipe bursting, directional drilling and microtunnelling • Good chemical resistance: Outstanding resistance to a wide range of chemical reagents allows the use of polyethylene systems in applications such as tailings pipelines and chemical treatment applications used in mining operations • Flexibility: The ability to be bent to a minimum bending radius of 30 times the pipe’s outside diameter is critical in applications such as submarine pipelines, mine subsidence and earthquake-prone areas. The inherent resilience and flexibility of HDPE pipe allows it to absorb surge pressures, vibrations and stresses caused by soil movement • Good abrasion resistance: Pipes can provide long life in abrasive slurry applications, conistently outlasting other pipe materials such as mild steel and rubber-lined steel • Good UV resistance: The inclusion of carbon black in the raw material means that pipes are stabilised against ultraviolet light degradation, making them suitable for installation where pipes are exposed to direct sunlight • Cost efficiency: good value over time is guaranteed

IMIESA April 2018

29

SASTT Trenchless News

To watch a video of this process, use the following QR code:

Connection between the ±150 m long lengths of installed HDPE was achieved by means of electrofusion couplings and off-shoots by means of electrofusion saddles, to provide a complete HDPE solution. End-point and scour-valve connections were achieved by HDPE stub-ends and backing flanges

Safe asbestos removal Integral to the project was an asbestos removal plan for the safe disposal of contaminated waste approved by the Department of Labour.

All launch, receiving and catchment pits were lined with 250 µm plastic sheeting to contain the bentonite, spoil, asbestos and water. This was removed using a Kosun KSMR-250 mud separation system. Once separated, the bentonite and water mix was reused in the pipe reaming process, and later filtered and disposed of.

“An interesting facet of the AC removal works was that it became apparent that one is able to control the amount of AC that enters the bentonite mix by the design of and selection of the pipe reamers’ cutting teeth, as well as the design of the bentonite mix itself, to significantly reduce the volumes of contaminated waste,” explains Camarda.

A global solution “The Temba project demonstrated the successful use of pipe reaming technology

to replace ageing AC pipeline infrastructure without disruption to overhead powerlines,” says Camarda.

He believes this technology offers a relatively cost-effective and efficient trenchless alternative to the South African industry for both large- and small-diameter pipe replacements.

Internationally, many countries are not physically replacing their AC piping and are, instead, relining them. However, in this situation, the ability to utilise locally produced HDPE pipe results in pipe reaming being far more cost-effective than trenchless solutions that utilise any imported lining material.

“The pipe reaming process undertaken on this project provides a possible upsizing solution to owners of AC water piping, and lays the foundation of an acceptable methodology for dealing safely with the AC material during replacement works.

This could greatly aid South Africa and the international market by providing a viable solution to replace leaking AC water pipes in the future,” says Camarda.

IMIESA April 2018

31

Trenchless Technology Specialist

Our range of services include: • Pipe Bursting • Horizontal Directional Drilling • Pipe Rehabilitation

• Pipe Ramming • CCTV Inspection • Dewatering

• HDPE Welding • Deep Excavation and Shoring • Underground Service Detection

• Slip Lining

• Industrial Pipe Cleaning

• Close-fit lining: COMPACT PIPE

For more information you can contact us: +27 (0)21 761 3474 F +27 (0)21 797 1151 E info@tt-innovations.co.za www.tt-innovations.co.za

SASTT Trenchless News

No-Dig coming to SA in 2018 The ISTT’s International No-Dig Conference and Exhibition will take place on 8 and 9 October 2018 at the Cape Town Convention Centre, hosted by the South African Society for Trenchless Technology (SASTT).

P

reparations for the annual event continue at pace, with largescale pavilions from South Africa, China and Germany all already at the drawing board stage. Exhibition space has also been in high demand with over two thirds sold, reports Paul Harwood, managing director of the event organiser, Westrade Group. Interested parties are encouraged to sign up before space sells out.

Harwood recently returned from SASTT’s AGM in Johannesburg, commenting: “I have been blown away by the immense amount of work and support everyone is putting towards this show and the country’s universal enthusiasm to embrace trenchless technology. The official supporters and media partners that we have taken enormous pleasure in announcing will only further enhance the calibre and number of delegates attending this prestigious event.”

The call for papers has begun and will be open until early May. “As well as receiving a host of international papers, we are expecting a sizeable number to come from within our local trenchless community on the African continent. We invite authors to visit the show website to upload their 200-word abstract for consideration in our exciting conference programme,” says Sam Efrat, president, SASTT. No-Dig 2018 will include a comprehensive conference programme, assembled by a technical committee comprising representatives from SASTT and the ISTT, aimed to be both educational and practical, combining training modules with case study presentations. Hosted in Cape Town, the 2018 event will also include a tours programme, providing delegates with the opportunity to explore the city and its many attractions.

The event is officially supported by the South African Plastic Pipe Manufacturers Association (SAPPMA), South African Institute of Civil Engineers (SAICE) and Installation and Fabrication Plastics Pipe Association (IFPA) and sponsorships have been taken up by industry trailblazers Vermeer (platinum), Trenchless Technologies (gold), ELB Equipment (gold) and Herrenknecht (bronze).

Official media partner Trenchless International Magazine, the industry’s goto publication, will be joined by 3S Media’s IMIESA and Water&Sanitation Africa magazines, and Construction Review Magazine Kenya.

To find out more, visit www.nodigsouthafrica.com

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IMIESA April 2018

WATER

The largest of all the engineering design contracts for Phase II of the Lesotho Highlands Water Project (LHWP) was recently awarded, marking the star t of the next level in this mega infrastructure development.

By Liesl Frankson

P

hase II of the LHWP comprises two main components: a water transfer component to augment the delivery of water to South Africa and a hydropower component that is expected to increase the electricity generation capacity in Lesotho, to help meet the country’s electricity requirements.

The project is now moving into the design and construction phase, with the first three of approximately 20 infrastructure construction contracts having gone out to the market in the last quarter of 2017.

LHWP Phase II Raising the bar on development These contracts include work on the Polihali diversion tunnels, the Polihali North East Access Road (PNEAR) and the advance infrastructure civil works at Polihali and Katse.

According to Tente Tente, divisional manager: Phase II, Lesotho Highlands Development Authority (LHDA), the procurement process on all three is nearing completion.

“Based on projections, dam completion is scheduled for 2024 and the tunnel for end 2025, inclusive of commissioning,” he notes.

Scope of works The infrastructure construction contracts span many disciplines – including roads, bridges, housing, power, water supply and waste management – and Tente expects the advance

infrastructure to be largely completed before the start of the main works in 2020.

“The PNEAR – running from Mapholaneng to Polihali Dam – will be a 16 km class A road aimed at improving access to the dam site for construction vehicles. It will also substantially improve ease of movement for surrounding communities and is a major improvement on the current gravel road,” Tente notes.

Two diversion tunnels – which will be approximately 800 m and 850 m long respectively – will be excavated by drill and blast, with the aim of diverting the river’s water away from the natural river bed to ensure the dam foundation area is dry for construction.

In addition, the advance infrastructure civil works contract includes roads, water and Polihali weir

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33

WATER

Traditional Basotho huts in a village

wastewater systems, as well as electricity and telecoms supply to the Polihali village, which will be used by consultants and contractors during the construction of Phase II and by the LHDA’s Field Operations Branch on completion of the construction.

Investing in people While construction on the transfer tunnel is only expected to begin in 2020, the start of construction works on Phase II is set to begin in the first quarter of 2018, marking the start of the phase’s sixyear construction period and the eagerly anticipated employment opportunities it brings.

“Phase II comprises a range of small and large contracts. It offers contractors work continuity for a number of years and the opportunity to gain valuable experience on a large infrastructure project,” Tente says.

The LHDA says Phase II promises a sizeable investment into the people of Lesotho, South Africa and the broader Southern African region. “Skills and technology transfer is embedded in the procurement and contract documents, and the attainment of specified targets will be carefully monitored and enforced,” he says.

As a general rule, the LHDA says preference will first be given to Lesotho nationals, South African nationals, and professionals from the SADC region and only then to internationals, subject to conditions on quality, competitiveness, transparency and cost-effectiveness being met.

“There is a mandatory requirement to meet specified minimum participation of Lesotho companies and South African black-owned companies in the form of joint ventures or subcontractors. Over and above this, tendering entities are also required to pledge a percentage of their tender sum for enterprise development of the emerging Lesotho companies, South African black-owned companies and women-owned companies. Exceeding the mandatory minimum target attracts preference points during the tender evaluation,” Tente explains.

The LHDA also has a ‘young professionals’ programme through which a number of new graduates will be given an opportunity to gain experience and learn by job shadowing and working under the guidance of more experienced personnel. There will also be an internship programme where the LHDA will financially support undergraduates studying in the relevant disciplines.

“So, the LHDA is not only supporting the JVs between South African BBBEE and Basotho contractors, it is also promoting the skills and technology transfer to companies and individuals. Furthermore, in order to provide opportunities to as many contractors as is practicable, the project’s works have been broken down into a substantial number of small, separate construction contracts,” Tente notes.

Uplifting the community While Phase II is still in the early stages, Tente believes its implementation is expected to benefit the Mokhotlong community.

“These benefits will include improved access resulting from the building of new roads and bridges, and improving the telecommunications infrastructure, improved public health facilities and access to water and sanitation,” he notes.

In addition to employment opportunities created by the works themselves, Tente also expects additional employment opportunities to arise as a result of increased tourism to the region.

“Tourism will increase and will bring opportunities that include, among others, new hospitality-related services and products,

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IMIESA April 2018

WATER Polihali Dam site measuring weir

employment in hospitality establishments, accommodation services, tour guide services, food production, transportation services, and the provision of other basic human requirements that tourists purchase along with souvenirs.”

According to Tente, the LHDA will also implement sustainable livelihood restoration support projects for the benefit of households affected by Phase II. “The intention is to offer support to the affected households through projects of their choice with advice from the LHDA and experts in livelihood restoration. These projects will look at land-based, wage-based and enterprise-based options.”

The Phase II community development initiatives will be planned and implemented in all the communities in the project areas. “Consultations with affected communities have been at the core of identifying appropriate projects, ensuring that these address the needs of the people concerned. Pilot projects are to commence in the areas affected by Phase II in early 2018,” he concludes.

Progress of design consultancy tenders awarded thus far • Access roads – Evaluation process of the tenders for construction of the PNEAR is under way. The design of the Polihali Western Access Road is advanced and the project is approaching the construction tender stage.

• Tunnels – Evaluation process of the tenders for construction of the diversion tunnels is nearing completion. Following the recent appointment, the Polihali transfer tunnel consultant has mobilised and initial tasks are in progress.

• Polihali Dam – Design of the dam components, e.g. spillway, outlet works, main dam and intake tower, is in progress and stage two of the geotechnical investigations is under way.

• Hydropower – The further feasibility studies are at an advanced stage.

• Village and construction camps – Evaluation process of the tenders for construction of infrastructure civil works contract is nearing completion. This will shortly be followed by the advertisement for the construction of houses, lodge and operation centre.

• Environmental and socio-economic – Cultural heritage management fieldwork has commenced following the recent appointment of the consultant. Resettlement action planning is progressing with asset registration under way.

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WATER

A new normal South Africa’s water and sanitation sector is facing myriad challenges, including the drought currently gripping the Cape. The Water and Sanitation Master Plan seeks to provide solutions.

By Danielle Petterson

D

eteriorating water quality, and Sanitation (DWS), the water sector stakeholders insuf ficient water problem is much broader in South Africa to work infrastructure maintenance than this. together to ensure and investment, recurrent The constitutional that the country droughts, inequities in access to water responsibility to supply has a sufficient and sanitation, and a lack of skilled water water and sanitation lies reserve of supply people do not have engineers are all causing a water crisis, with 144 municipalities to meet Sustainable access to which is already having significant impacts that are water services Development Goal 6 safe sanitation on economic growth and the well-being authorities. However, at – access to water and of residents. least 33% of these sanitation for all – by 2030.

In South Africa, 5.3 million municipalities are According to Balzer, the plan, households (35%) do not regarded as dysfunctional which is driven by a sense of urgency, sets have access to reliable and more than 50% out prioritised actions and investments drinking water, while have no or very limited that the country must implement between 14.1 million people technical staff, says now and 2030 to overcome challenges and do not have access Balzer. ensure a water-secure future supporting to safe sanitation.

Municipal non-revenue inclusive development across the country. households do not However, according water is currently at a high These are accompanied by roles and have access to reliable to Trevor Balzer, DDG: of 41%, which equates to a responsibilities, targets and time frames drinking water Strategic and Emergency loss of roughly 1 660 million against which relevant players in the Projects, Department of Water m³ of water per year amounting sector can be held accountable by Cabinet, to R9.9 billion. Moreover, 11% of water Parliament and the public. supply schemes are fully dysfunctional, while The NW&SMP is based on five Trevor Balzer, DDG: Strategic and approximately 56% of wastewater treatment key objectives: Emergency Projects, Department of works and 44% of water treatment works are 1. Resilient and fit-for-use water supply Water and Sanitation in poor or critical condition and in need of 2. Universal water and sanitation provision urgent rehabilitation.

3.

Equitable sharing and allocation of Balzer believes that in order to combat this water resources and achieve water security in South Africa, 4.

Effective infrastructure management, a ‘new normal’ is needed. This significant operation and maintenance paradigm shift means that water will become 5. Reduction in future water demand. more expensive, consumption will have to be reduced and everyone, except the indigent, Water supply challenges “Our water availability could deteriorate rapidly must pay for services. as our supply contracts and demand escalate A national plan due to growth, urbanisation, inefficient use, The National Water and Sanitation Master degradation of wetlands, water losses and Plan (NW&SMP) currently being developed by the negative impacts of climate change,” the DWS is a call to action. It seeks to rally all says Balzer.

14.1 million

5.3 million

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IMIESA April 2018

WATER

41% of municipal water does not generate revenue

Towards a Based on projections, the water however, the sector is facing a diversified supply deficit could be between 2 700 and R33 billion funding gap The NW&SMP seeks to 3 800 million m3 per annum by 2030 – a each year, which must be diversify South Africa’s gap of about 17% of available surface water urgently addressed. This water supply, moving and groundwater. This will require serious funding is needed for away from the current interventions to reduce demand and critical refurbishments, water mix, which is losses, especially in the agriculture and water supply and of WWTWs and 44% of strongly dominated municipal sectors, by improving efficiency, infrastructure renewals.

WTWs are in a poor or by surface water, to a adopting new technologies, and reducing To address this deficit, critical condition water mix that includes losses through water awareness, and strict the sector needs to look increased groundwater regulation and incentives, explains Balzer. at financial leakage, improving use, reuse of effluent from One of the first interventions is to cost recovery, increasing tariffs, wastewater treatment plants, reduce consumer demand. Average private investments, PPPs, loan funding water reclamation, as well as municipal water use in South and bonds, says Balzer. However, only desalination and treated acid Africa is around 237 ℓ per the metros and three of the major water mine drainage (AMD). By person per day, compared boards are stable enough to go into the 2040, the DWS aims to the world average market and raise funding for water and to have 60% surface of 173 ℓ per person sanitation infrastructure. water contribution, 20% per day. “Since large If nothing is done, South Africa’s water and groundwater, 14% reuse, numbers of South sanitation sector faces a glaring financial 4% desalination, and 2% Africans use very deficit, which will inhibit the country’s ability South Africa is facing treated AMD. small amounts of water to provide essential services. a projected 17% water However, a diversified per day, this average deficit by 2030 An urgent intervention supply alone will still result masks the high water use Work on the NW&SMP is still in progress in a 5% water deficit by 2030. If, by privileged sectors of the to develop the multiyear, detailed schedule on top of this, urban losses are reduced population,” says Balzer. Average of actions for implementation between from 35% to 15%, water supply and demand domestic consumption must therefore 2018 and 2030. This schedule will balance out. However, it is only be reduced to 175 ℓ per person per day of actions will be prioritised and by reducing domestic demand to by 2025. refined in consultation with all 175 ℓ per person per day that There are also significant opportunities stakeholders during the South Africa will have an 8% to reduce water demand in the proposed mini Phakisa surplus by 2030 – what irrigation sector. Currently, agricultural scheduled to take place Balzer refers to as a consumption is largely unmetered, and towards the end of “comfort zone”. there are concerns about unauthorised August 2018. abstraction and water wastage in the Budget deficit Ultimately, South sector. Agricultural users also pay a South Africa is facing a The DWS estimates that Africa is facing a much lower tariff than other users R33 billion funding gap it should be investing projected 17% water of untreated water, which has not each year for the next R90 billion per annum into deficit by 2030 if it doesn’t incentivised the adoption of water10 years water for the next 10 years; adopt the ‘new normal’. efficient irrigation practices.

56%

17%

R33 billion

IMIESA April 2018

37

WATER

Creative responses to water security Groundwater extraction and desalination are some of the interventions being implemented by water-scarce regions. The next step is to ensure potable water quality, which requires specialist technologies and expertise, areas where Quality Filtration Systems (QFS) has years of project experience. Here are two examples.

B

y securing the contract to provide an emergency desalination plant for the Victoria & Alfred (V&A) Waterfront in Cape Town, QFS addresses the increasing water demands of the metropolitan region.

The project involved the supply, installation and commissioning of a fully containerised 2 MLD seawater reverse osmosis and multimedia filtration plant, delivered under a rental contract for a minimum duration of 24 months.

Following the City of Cape Townâ&#x20AC;&#x2122;s need to augment severely restricted potable water supplies, the collaboration of QFS and Osmoflo on this project will help to bring fast relief to the severe water shortages in the area.

QFS has been building membrane plants since 1999 and focuses on membrane-based water treatment for seawater desalination, wastewater reuse and brackish water treatment.

Drought relief (2 MLD) desalination project in the V&A Waterfront, Cape Town

Containerised borehole water treatment plant (1.5 MLD)

“The V&A desalination project feels like the culmination of years of promoting membrane equipment for the treatment of potable water and wastewater,” says Herman Smit, MD at QFS. “It is satisfying to use our 21 years of experience to contribute to the Cape Town augmentation programme for some relief during the drought.”

The importance of water security Water security is categorised into three different levels. The first level is for drinking, cooking and sanitation. The second focuses on agriculture, and the third on the environment.

First-level case study: Val de Vie estate The problem: With Day Zero fast approaching at the time, the management of the Val de Vie estate in Franschhoek had to formulate a plan to counter the severe drought conditions being experienced.

The solution: In 2017, QFS was awarded the contract to design, manufacture, install and run a completely off-grid automated (1.5 MLD) water filtration plant for Val de Vie. This would also alleviate the pressure on municipal infrastructure.

The plant was designed and manufactured as a modular, twocontainerised system consisting of one 12 m and one 6 m container.

The 6 m unit houses the water pumps and chemical dosing equipment.

The water pumps are all in a duty/standby configuration. This builtin redundancy ensures plant uptime. In turn, the 12 m high-cube container houses the filtration equipment, electrical cabinets and the fully automated computerised control system.

The plant is fed by eight boreholes scattered across the Val de Vie landscape, which are fully automated and controlled by the main plant.

The flow, level and pressure of each borehole are closely monitored and the information is sent via microwave radio to the automation system. A complex algorithm is used to ensure that water is extracted from the ground in an efficient and responsible manner.

Quality inspections, and chemical and microbial analyses by a SANAS-approved laboratory ensure that the water meets and exceeds all safety and quality specifications.

The outcome By making use of state-of-the-art technology, proven engineering principles and excellent workmanship, QFS has ensured water security for the residents of Val de Vie for many years to come.

Consulting Engineering

Partnerships and value engineering

Jacob Mamabolo, Gauteng MEC: Infrastructure Development

Government is calling for more engagement from the construction sector, which presents a great opportunity for consulting engineers. The keynote address delivered by Jacob Mamabolo, Gauteng MEC: Infrastructure Development, at the recent CESA Infrastructure Indaba is a step in the right direction. By Alastair Currie

T

he subdued trading conditions in the South African construction industry remain a major cause for concern as bottom lines come under increasing pressure. Since around 60% of the revenue earned by consulting engineers is sourced from the public sector, government’s ability to efficiently deliver on its infrastructure mandate is critical for the longer-term sustainability of these businesses.

Within the Gauteng region, one of the positive change agents that could help correct the current project deficit is the Department of Infrastructure Development (DID). The DID manages a property portfolio of over R32 billion, and is developing project and procurement management systems that could soon be replicated across other public entities.

“At a time when construction industry confidence levels are at their lowest, our priority as government is to analyse the underlying causes and find solutions together to revitalise this critical sector of our economy,” said Mamabolo. “It’s a conundrum because we’ve invested around a trillion rand in infrastructure development. So why, then, is the construction industry in such a depressed state?”

The DID is responsible for managing all infrastructure roll-outs in the Gauteng region and is committed to unlocking value. A good example is the way the DID is partnering with tertiary institutions to develop sustainable infrastructure solutions that meet the pressing need for student accommodation by converting disused public buildings into

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IMIESA April 2018

productive assets. The DID’s broader end goal is to establish viable industrial, commercial and residential precincts that make full use of available land parcels.

All in the execution Mamabolo says one of the key issues is the delay in project execution, and the ensuing quality and cost overrun concerns. These and other areas are now being tackled as a priority DID intervention.

At the heart of this initiative is Lutsinga Infrastructure House (LIH), a technology nerve centre that is revolutionising the way public projects are delivered now and in the future. In conjunction with the DID’s Project Readiness Matrix (a programme management tool), the team at LIH has access to accurate and near real-time data on the status of all construction, maintenance, design and planning phases, including procurement processes and approvals. All elements tie in with the Gauteng and National Treasury databases. That means no work happens without prior scrutiny and approvals.

“Budget allocations are tighter these days due to external and internal economic influences. However, the current financial constraints being experienced in South African construction are not solely due to a lack of money, because billions have been committed to infrastructure over the next three years of the medium-term expenditure framework,” Mamabolo continued.

“My argument is that one of the main causes for the shortfall in public sector construction activity, generally, can be attributed to the current ‘end-to-end’

Consulting Engineering

management techniques being applied. These are not at the right level and what we’re seeing is a ‘ping pong’ approach, where projects go back and forth due to incomplete information,” said Mamabolo. “That’s why we’re now applying the right project management tools, and this is DID’s contribution to removing the current bureaucratic constraints.

“We’re also piloting the use of drones so that we can monitor and verify construction work in progress. Historically, one of the chief obstacles to paying contractors and consultants within the 30-day period stipulated by government has been the unreliability of available project data.”

The DID has so far tested around 340 projects using the Project Readiness Matrix. Some 63 projects have been validated for the 2018/19 financial year and are confirmed, including school, clinic and hospital developments, in addition to various building retrofit projects.

Corruption: public and private Mamabolo said that the issue of corruption is also being tackled head on, from both a public and private perspective, stressing that everyone is responsible for maintaining the highest

engineering standards. And it’s a two-way well into the future, with minimal maintenance. street. “The ‘instruction to perform work’ (IPW) Green buildings are definitely the future.” procurement tool is an example of how money On a closing note, Mamabolo said the can be wasted through poor project planning consulting engineering sector has a key role to and implementation. On top of this, IPWs are play in supporting the government’s job creation also open to abuse and potential fraud. Either agenda, which includes the pressing need to way, billions of rands that could have been solve youth unemployment. “Consultants must allocated to other projects have been misspent embrace labour-intensive construction as one in recent years.” of the solutions, which means developing the The IPW protocol is intended to make engineering skills necessary to incorporate exceptional funding provision available for these methodologies into project designs. projects due to unforeseen “I’m proposing that the Green buildings DID and CESA work together circumstances. When this needs to be challenged in to pilot a number of labourare definitely court, this causes further intensive projects. Let’s see the future.” delays. “However, with the how we can make it work correct application of risk profiling, contractors and, in the process, create employment for and consultants should be able to anticipate young black engineers seeking experience and potential snags well ahead of time to avoid IPW subsequent professional registration on these payments,” he assertsed. and other projects,” he added.

“At the DID, we are excited to work with Green buildings engineers who have a social conscience and to “We are also emphasising the need for the partner with CESA going forward. This includes a correct application of building materials and proposal to sign a memorandum of understanding technologies, and design and construction that will more effectively harness CESA’s qualitypractices, so that completed projects will survive based consulting engineering services.”

Transforming our world

AECOM ‘s experts are committed to providing innovative solutions to our clients’ projects while bringing together people and stimulating economies to create new possibilities.

The realignment of approximately 4 km of the National Route 7 Section 3 for the proposed raising of the Clanwilliam Dam, Western Cape (Project Management, Detail Assessment & Design (incl. Bridge Specialist Design Services) and Contract Management Services.

Redhouse Chelsea Interchange and Arterial Road’s Project, Port Elizabeth (Design Management & Supervision Services)

Bridal Veil Road Overpass Bridge, Gauteng (Design & Construction Management Services)

Building Systems

Partitions with a difference For designers and project managers, the availability of alternative building systems is always welcomed, especially when it comes to competitive pricing and fast-tracked contracts. An innovative fabrication approach from Finland takes this a step further by adding safety, comfort and durability.

P

recast technologies provide seemingly boundless opportunities for design and innovation, a case in point being Elematic’s Acotec system, which can be installed up to six times faster than a conventional partition wall.

Acotec non-load-bearing precast partition wall elements can be used in a diverse range of applications. These include residential apartments, hospitals, schools,

warehouses, security fencing and noise barriers. Since these panels are made from Leca (lightweight expanded clay aggregate) or concrete, they are highly durable, ensuring great resistance against moisture and temperature fluctuations, while also dampening sound.

“The engineering and utility rooms in hospitals and office buildings are often full of noisy equipment, so the sound insulation of the partition walls has to

Wall panels cemented to the floor and ceiling, while adjoining panels are bonded together with an adhesive

be good… and it is, when using Acotec panels,” explains Jani Eilola, product director, Elematic – a specialist precast machine line manufacturer based in Finland and represented globally, including in South Africa.

“Thanks to the innovative manufacturing method we’ve developed, the length and thickness of the wall can be adjusted on the production line in accordance with the application and the construction requirements,” he continues.

Depending on the wall thickness specified, these panels offer up to 120 minutes of fire resistance, which is a vital quality generally, and especially in places like hospitals where evacuation takes longer.’

Rapid installation Thanks to their standardised shape and light structure, Acotec panels can be installed at rates of up to 90 m2 per day by two workers (the average being 50 m2). Even in comparison to block partitions, Acotec installations are up to three times faster, making it a

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IMIESA April 2018

Building Systems cost-effective solution. The panel width is either 30 cm or 60 cm, with no limitation on height.

During installation, Acotec elements are lifted into an upright position and then cemented at the floor and ceiling contact points, with the ceiling joints sealed with adhesive. The panels are bound together with highquality joint glue.

“Elematic Acotec fabrication machine lines cover the entire panel production process from concrete batching all the way to storage yard management and beyond.

They’re automated and ver y reliable, as they consist of proven, standard components.

For existing or new SMME entrants to the precast market, acquiring an Acotec unit is a great way to expand or start your business,” Eilola concludes.

Three technology levels: SEMI, PRO and EDGE The SEMI line, with a production capacity of 80 m2 per hour, is the simplest of the three variants and is an excellent choice for anyone starting up in the business. It features automation only for the key processes.

The PRO line offers a higher capacity of 100 m2 per hour, with automated functions for all main processes: sawing, trimming, stacking, restacking, cleaning and oiling, plate handling and pallet circulation.

The fully automatic EDGE line offers a top-rate capacity of 120 m2 per hour and needs only two operators to run.

All the lines feature an advanced production control system and a simple, modern user interface, which shows detailed data on every function across the entire process. Various reports, such as production volumes and running times, are generated automatically.

Their modular structure and integrated EtherCAT bus system guarantee quick installation and start-up, plus these lines can be installed in existing production facilities. The production process is silent and non-vibrating, and the raw material can be recycled, minimising waste. As a further plus, low energy consumption keeps down production costs.

The Elematic production line also features an innovative Atrex crushing mixer, which enables the use of lightweight aggregate up to grade 30 as the raw material. This comes in handy as Leca is manufactured worldwide from natural materials and, therefore, particles vary slightly from country to country.

Table 1 Comparison of panel installations

ELEMATIC ACOTEC

SEMI

Nominal production capacity 80 m /h 2

PRO

EDGE

100 m /h 2

120 m2/h

Production personnel

5–7

3–4

1–2

Required factory space

900 m2

900 m2

900 m2

Required land area

3 000 m2 – 5 000 m2

3 000 m2 – 5 000 m2

3 000 m2 – 5 000 m2

Slab length

2 200 mm – 3 300 mm

2 200 mm – 3 300 mm

2 200 mm – 3 300 mm

Slab thickness

68 mm – 120 mm

68 mm – 120 mm

68 mm – 120 mm

Slab width

600 mm (300 mm also available)

600 mm (300 mm also available)

600 mm (300 mm also available)

www.corobrik.co.za | info@corobrik.co.za

Building Systems

Education and bricks Educational facilities need to be functional and safe, and they also need to be energy efficient, which is where clay bricks and pavers play a key role.

On top of that, aesthetics are equally important.

W

hen it comes to thermal mass, few materials excel as well as clay brick in effectively regulating building interiors, helping to keep them warm in winter and cool in summer.

“The thermal mass and thermal capacity of face bricks essentially help them to perform like batteries, absorbing heat in the day and releasing it overnight when it’s needed, through a process of thermal lag,” explains Musa Shangase, commercial director, Corobrik. “This means that the interior is kept at a more comfortable temperature.”

These beneficial features continue to make clay brick a material of choice for creative architectural designs. Recent South African project examples include a student accommodation building for the Shukela Training Centre (STC) in Mount Edgecombe, KwaZulu-Natal. This three-storey structure, consisting of 86 rooms, was commissioned by the

South African Sugar Association (SASA). For the STC building, architectural firm i3LAB selected Country Meadow Satin face bricks for the external façade, with the paving phase completed in Corobrik’s Cederberg and De Hoop pavers.

“The KwaZulu-Natal coastal climate is renowned for its hot, humid summer days, which can be problematic for buildings, with instances such as damp and mould leading to ‘sick building syndrome’,” he explains. “This is not true of buildings constructed using Corobrik’s range of face bricks. The fired clay brick absorbs and releases humidity from the atmosphere so that it is kept at 40% to 60% – ideal for healthy living.”

Intelligent ventilation The architects at i3LAB were also able to achieve indoor temperature moderation using intelligent ventilation techniques throughout the building. The balcony, escape and main stairwells all have weather louvres to allow for cross-ventilation and bedroom doors are fitted with operable fan lights. The architects’ choice

of cavity wall construction further enhances the thermal efficiency of the building.

Corobrik’s De Hoop pavers were used in the parking area, with the Cederberg pavers used for walkways. In addition to the aesthetics, skid resistance and colour fastness of the clay pavers, they also exhibit excellent thermal efficiency, ensuring that they don’t overheat in the direct sun.

Menlyn Learning Hub Another recent education-related project is the Menlyn Learning Hub within Menlo Park, Pretoria, which features Corobrik’s latest range of 65 mm graphite pavers.

Designed by Boogertman + Partners, this contemporary, five-storey educational facility currently caters for approximately 2 500 students, with future expansion plans in place. The 23 012 m² development includes administration blocks, a canteen area, an external piazza seating area, lecture rooms and a library.

Corobrik’s graphite paver is straightedged, producing a crisp, modern finish that

IMIESA April 2018

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Building Systems

complements everything from inner-city developments to educational facilities. “Another important consideration in the creation of the graphite paver was its universal design,” says Shangase. “Smooth surfaces, as opposed to bevelled or rough surfaces, enable individuals with restricted mobility better access to pedestrian spaces. Corobrik developed this paver to have almost no bevel, ensuring a universally friendlier movement space.”

Approximately 71 500 Corobrik graphite pavers were used throughout the development, which included the piazza seating area, walkways, as well as around the building’s perimeter. The graphite was selected, in part, because of the colour contrast created against the concrete pavers used in the development.

There was an overriding need for the design of Menlyn Learning Hub to tie in to the natural environment. This meant the use of indigenous planting and permeable paving in the form of Corobrik’s clay pavers, to allow water to penetrate the surface, replenishing groundwater below.

“The earthiness of the graphite paver, in colour, texture and form, makes it the perfect connection between the natural environment and the physical building,” concludes Shangase. “It’s a product that has been beautifully represented in this very inspired design.”

®

CONSISTENCY. IT’S WHAT WE’RE MADE OF. A range of products built on the foundation of quality and durability Aggregates Concrete Based Products Industrial Minerals Contracting International Commodities

The Shukela Training Centre student accommodation building in Mount Edgecombe has been constructed from Corobrik’s Country Meadow Satin face bricks, with paving completed in Corobrik’s Cederberg 50 mm pavers on walkways and De Hoop red 73 mm pavers on roadways (Photo credit: i3LAB)

Inspiring growth through the consistent delivery of solutions that empower our people and our customers.

The Aggregates Division is a key division within Afrimat Limited producing aggregates of a wide variety of sizes and technical specifications, primarily with products including stone, gravel, crushed aggregates, laterite and sand mainly for large-scale civil engineering and infrastructure projects.

It also provides professional contracted drilling & blasting, transport & logistics crushing & screening and earthmoving & plant hire services.

The Aggregates Division is located in seven of South Africa’s provinces with commercial quarries including sand mines, gravel mines, mobile crushing, recycled concrete crushing plant and drilling & blasting.

The Aggregates Division is part of Afrimat Limited, a leading black empowered open pit mining company.

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Solid Waste

Maximising landfill airspace Landfills are not dumping grounds: they are engineering systems that need a precise project management approach coupled with the correct spreading and compaction techniques. By Nick Mannie*

A

shift in environmental awareness and an increased focus on sustainability have prompted authorities to carefully review the granting of permits for new landfills. The focus and change in permitting is giving rise to “not business as usual in the waste industry”.

A shift in thinking and behaviour is the norm presenting itself to all waste generators and operators to provide sustainable environments and reduced airspace consumption. This action applies to both private and public officials. Both groups have a common goal: to conserve airspace.

This action is resulting in owners and operators being required to take a more economic view of managing their landfills.

This particularly applies to the consumption of airspace by ‘bulky’ waste and waste types that contribute to a carbon-rich environment, food waste producing vast amounts of landfill

gas, and where waste types like paper and plastics could easily be recycled, prompting households to use recycled paper.

The planning of waste disposal is based on climatology, cell design, waste volume information, waste generation and waste characterisation trends, growth rates and economic information. With this information in hand, a number of assumptions and scenarios can be sketched out for use of landfill airspace.

Optimal compaction It’s extremely impor tant that adequate compaction be achieved daily to avoid consuming unnecessary airspace. If the need arises to increase airspace availability due to increased waste tonnages, the operator will be required to conduct detailed modelling either from a lateral or vertical perspective. This will determine the most sufficient airspace gain, while ensuring all risk issues have been sufficiently managed in the design process. It should be borne in mind that the planning of

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Solid Waste

on the correct placement of waste loads coming into the landfill site. Difficult waste streams – such as concrete, bulky green waste and rubble – should be tipped closer to the working face rather than in the distance to avoid long pushes.

The landfill compactor is the single most important machine on a landfill site and the following recommendations apply: • Make sure you have the right specified equipment.

• It is not the volume of waste, but the density of the waste that is always the challenge in compaction. For this reason, avoid bulky waste at all costs.

• Working in acceptable lifts, not too high, is the most effective way to increase the number of compactor tooth penetrations.

• The compactor should not travel over long distances, as it could create other issues such as wind-blown litter, nor over areas where large portions of bulky waste have been disposed.

• An important consideration in determining the airspace is the placement of cover material over the waste lifts. The thicker the

*Nick Mannie is the client manager: Government RSA at Aurecon.

disposal activities is crucial to determining the lifespan of the cells or landfill. The type of waste, the thickness at which it is placed, and the frequency of waste disposal all have an influence on the rate of airspace consumption. Careful analysis of waste type trends and tonnages is a good gauge to estimate future available airspace volumes.

A holistic approach Pushing waste from where it is dumped to the working face (active cell) plays an important role. This sets the tone of the operations, placing the right type of waste in the right cell, at the right time.

To achieve optimal waste compaction, the focus is not only on the compactor, but also

placement, the greater the use of airspace.

It is good practice to ensure that the correct ratio of waste to cover is applied throughout the disposal and compaction process.

Diversion of waste The increasing rate of urbanisation, particularly in South Africa’s major metropolitan cities, is forcing operators and municipalities to seek alternatives to landfilling. Legislation and the need to follow the waste hierarchy are prompting the increase in recycling as well as finding alternative uses for some of the problematic waste types.

By enforcing this practice, the need for additional airspace is avoided and the disposal of economically valuable waste or materials is reduced. The benefit of this practice ensures the promotion of the circular economy. And the diversion of waste further limits the impact of landfills on the environment.

Additionally, recycling and diversion create new opportunities for waste to be managed and treated innovatively and with new technology, which has major downstream benefits.

IMIESA April 2018

Specialist Waste Management Consultants • • • • • •

Waste Collection Optimisation Waste Transfer Station design General Waste Landfill design Hazardous Waste Landfill design Landfill Rehabilitation Landfill Auditing and Monitoring

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Telephone:+27 (0)21 982 6570 Fax:+27 (0)21 981 0868

• • • • • •

Landfill Closure Leachate Treatment Regional Waste Studies PPP Involvement in Waste Management Alternative Technologies for Waste Reduction Integrated Waste Management Plans

Physical Address

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49

Photo credit: iX engineers

Labour-intensive construction

EPWP projects have potential Within the infrastructure segment, labour-intensive construction is public policy, but its execution has been poor to date. However, a renewed focus could yield major socio-economic benefits and it begins with re-education and training. By Robert McCutcheon*

D

espite the relative failure of the Expanded Public Works Programme’s (EPWP’s) infrastructure sector roll-outs over the past 13 years, there have been some important developments that could provide a more meaningful implementation strategy going forward.

Key reasons for past failures have come about due to external and internal factors.

The latter include the absence of a clear programme, plus errors during implementation.

The main external reason is the construction industry’s traditional preference for fuelpowered heavy equipment, from conception to completion. Another is the general lack of understanding within the public sector authorities responsible for expenditure of the principles and potential of labour-intensive construction. Consequently, there is little or no appreciation of what has to be put in place to achieve the potential.

Internal roadblocks The overarching obstacle internally is the route adopted for implementation,

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IMIESA April 2018

which differs significantly from the successful model applied elsewhere in sub-Saharan Africa.

Simply put, the process required to establish and implement a large-scale, longterm programme has not been considered by the EPWP implementers. With an overall allocation of more than R500 billion and an infrastructure sector expenditure of R129 billion, it should have been approached with the same seriousness and commitment given to megaprojects like the Medupi Power Station, the Lesotho Highlands Water Scheme or Gautrain. Instead, it was decided that delivery should be via small contractors, scattered throughout South Africa in over 10 000 independent projects.

Errors during implementation The lack of effective training definitely impeded the process. This was compounded upfront by the absence of specific, integrated technical and managerial training.

Therefore, a fundamental component of the process required for large-scale, long-term implementation was not set in place.

Elsewhere in Africa, large-scale, long-term programmes established historically ensured that the scale of construction was formally linked to, and dependent upon, the training of engineers and ‘hands-on’ single- and multisite supervisors – the latter being critical for the smooth running of the process.

It cannot be overstated that specific training is required for all concerned, at all levels: national, provincial and local authorities, engineers (site and design), as well as skilled site personnel.

Although both NQF5 and NQF7 training was carried out during South Africa’s previous EPWP initiatives, it was ineffective given the lack of improvement in labour-intensity.

It seems that the difficulties of actual implementation overcame any knowledge gained during the training. In addition, there was probably insufficient orientation of senior decision-makers. Plus, the overall emphasis on SME contractors did not achieve the anticipated results.

It is most disturbing that by the end of Phase II (March 2014), the EPWP had still not established a specific training college. However, in the original June 2004 Consolidated Programme Overview and Logical Framework, it was stated that a National Training Centre would be established as an intrinsic component of the overall outcomes.

Extensive experience has proved that modern labour-intensive methods are applicable for a wide range of civil

Labour-intensive construction

The EPWP Guidelines were too superficial to have any effect upon skills development and labour-intensity.” construction operations, such as excavation, load, haul, unload and spread operations. However, the Division of Revenue’s mandatory conditions for expenditure of Provincial and Municipal Infrastructure Grant (PIG and MIG) funds on specific categories of infrastructure related to labour-intensive activities were simply ignored for lowvolume roads, stormwater drainage, sidewalks and trenches.

Engineers did not prepare the appropriate designs, specifications and contract documentation required for modern labour-intensive construction. Additionally, the amount of time and effort required to re-engineer products and processes on specific projects, to incorporate labour-intensive techniques, was not taken into account by either engineers or policymakers. Unless this situation is corrected, it will impact on the EPWP’s future labour-intensive goals, which entered its third five-year phase in April 2014.

For large-scale, long-term implementation, we must establish linked training, construction and maintenance programmes. Where possible, this should include the establishment of in-house public sector capacity.

At project level and under current conditions, the consultant has to re-engineer product and process. The amount of time, effort and commitment required must not be underestimated, especially since the emphasis on using small contractors will continue to be a major focus.

The contractor must also fulfil the demands of the contract.

But this requires knowledge and experience on the part of the client, consultant and contractor to ensure that the design and contract documentation is correct.

The stipulations of the contract must also be enforced, just as they would in the conventional construction industry.

Today’s consulting engineers are expected to achieve a balance between infrastructure delivery and government’s socio-economic objectives. There needs to be a clear distinction between the two when it comes to labour-intensive versus conventional, mechanised-based construction as a transformation objective. A positive balance is definitely achieveable. *Robert McCutcheon is a professor emeritus and honorary professor of the School of Civil and Environmental Engineering at the University of the Witwatersrand. He is also the head: Employment Creation and Development at MPA Consulting Civil and Structural Engineers.

A fresh start On a positive note, all the mechanisms are in place to put the EPWP’s infrastructure programmes back on track using tried and tested techniques developed over the past 30 years in Africa.

Plus, these do not detract from government’s focus on social welfare support and upliftment. In fact, they help to cement and accelerate the process.

Across a wide range of building and infrastructure categories, there are now labour-intensive guidelines and background material in place for the formulation of design and contract documentation, including specifications and contract clauses. Training material and detailed courses have also been developed and approved, so there’s no need to reinvent the wheel.

Alongside the EPWP, oppor tunities for labour-intensive construction are also presented by the National Development Plan (NDP), which extends to 2030. Public employment programmes are included in the NDP, and the EPWP is mentioned as a prime example.The term ‘labour-intensive’ is included in the objectives of EPWP Phase III, thereby aligning it with legislation.

There is an EPWP Unit in the National Department of Public Works, together with a framework for implementation. The institution is staffed at national, provincial and local municipality levels, so the coverage opportunity is excellent.

Sanral is also preparing new specifications for labour-intensive construction, which is extremely important. Appropriate curricula for training have been established with accredited courses developed at NQF 2, 4, 5 and 7 levels.

So the upside is definitely there, since the budget allocations for Phase III of the EPWP are considerable, and we have the enabling policy and frameworks in place. Again, though, training is the critical component.

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Transport, Logistics, Vehicles & Equipment

Four pillars of excellence

V5+ lighting configuration

Air, flow, lighting and power solutions shape the future of Atlas Copco’s Power Technique business area, which is focused on meeting the mobility needs of construction, rental, drilling and allied industries. Alastair Currie speaks to David Stanford, business line manager: Portable Products, about future trends that add real value.

P

reviously known as Atlas Copco Construction Technique, this key Atlas Copco line was renamed in 2017 to reflect its evolving market focus, and the new entity, Power Technique, now more accurately defines its business objectives, both internationally and within the Southern African region.

This business unit is headquar tered in Belgium, while principal product development and manufacturing units are located in Europe, Asia, South and North America, as well as India.

Within Southern Africa, Power Technique has a direct customer interface, alongside specific dealer networks.

“Our goal is to supply products and solutions that power customer productivity, allied to which is the constant development of digital platforms that provide access to critical business information, such as condition monitoring and machine location, maintenance diagnostics, and online parts ordering,” explains Stanford. “QR codes are also being introduced on some machines that, which takes you directly to a mobile app. Overall, our intention is to make purchasing and decisionmaking faster and easier.”

The term that best defines Power Technique’s strategy is product mobility, driven either by electric or diesel motors, across a broad spectrum of products housed within four brand pillars.

These comprise air, flow, lighting and power.

“Our OEM designs across the spectrum ensure a purpose fit. Environmental efficiency is another important factor common to all products, with a core emphasis on minimising fuel consumption requirements,” says Stanford.

Air The air pillar comprises small, medium and large mobile compressors and caters for general construction, as well as more niche applications like blasting and drilling.

Versatility is a core research and development theme. For example, as Stanford points out, in past years, machines were designed solely for a specific pressure rating. That’s no longer the case, thanks to technological advances. “You can now optimise the pressure flow to complete a variety of tasks from a single machine, such as a 10 bar or 14 bar application, which really simplifies overall utilisation and passes on capex savings for fleet buyers,” he explains.

Other pneumatic products falling under this pillar include tools, rock drills and breakers. The hydraulic hammer line has now moved to Epiroc; however, petrol and hydraulic breakers remain part of the air line.

Within the comprehensive compressor range, one of the most popular for contractors is the XATS 1200 to X 1300 series (10 bar to 30 bar outputs), which is ideally suited for large infrastructure projects, like pipelines and borehole drilling.

“What’s unique for this model series is Atlas Copco’s development of PACE technology,

“Our intention is to make purchasing and decisionmaking faster and easier.”

IMIESA April 2018

53

Transport, Logistics, Vehicles & Equipment

A QES generator

introduced during 2017. This is essentially a dynamic optimisation feature. Operators can set up the engine to meet different pressures and flows, with the added benefit of improved fuel consumption during part loads,” says Stanford.

Power: mobile and fixed

The large air XATS 1200 to X 1300 series

“Across our four pillars, we’ve invested extensively in finding the right balance between sophistication and operational simplicity to meet in-field requirements.”

When it comes to generators, Atlas Copco is widely recognised as a leader in prime mobile power applications – construction being a core market. “We’re now also moving into what we classify as prime critical standby, which entails fixed-installation generators,” says Stanford.

In addition to serving as a backup for key facilities like hospitals, water and wastewater treatment works, commercial buildings, and manufacturing centres, Power Technique also caters for off-the-grid power requirements. That could include any remote requirement, from running a mobile asphalt plant to a mine. Since power here is frequently continuous, often on a 24-hour basis, fuel consumption clearly becomes an overriding factor from an operational cost perspective.

In response, Power Technique offers a fuel-optimised range and a value range – the former aimed at prime and critical standby.

“We are also piloting new technologies locally, which include generators equipped with variable-speed drive systems for more advanced requirements,” adds Stanford.

The Atlas Copco QES mobile generator series falls into the

value range for the construction industry. “The load stepability, noise and fuel consumption are among the best and this product is a bestseller, especially in the plant hire sector,” he explains.

Light Atlas Copco has made major R&D strides within its lighting series, moving away from older metal halide illumination to LED technologies, introducing its first LED line approximately 2.5 years ago.

Key benefits of LED include significant fuel savings and the stability of the light source itself. As an indication of efficiencies, Stanford says typical fuel burn rates can be as low as 0.5 ℓ per hour.

Units are supplied with a manual (V5+) or hydraulic mast (H5+) configuration, the latter proving increasingly popular due to its enhanced safety characteristics. Both models provide 5 000 m2 of illumination coverage. The H5+ model can also be equipped with a photo cell that will automatically start the engine to raise and lower the mast at sunset and sunrise.

Flow This is the newest of the four Power Technique pillars and Atlas Copco sees major potential for growth.

Current products comprise mobile electrical submersible pumps, and diesel or electric mobile dewatering units.

A current mainstream product is the PAS self-priming diesel pump line.

“We are currently operating in the medium head market, but also plan to move into the high head segment during 2018, targeting the mining industry as well as slurry and sludge type applications,” says Stanford.

“There’s also a focused expansion on new product introductions in the pipeline.

“Across our four pillars, we’ve invested extensively in finding the right balance between sophistication and operational simplicity to meet in-field requirements, backed by decades of industry experience. At Power Technique, we are firmly committed to working with our customers to package the best value proposition, and that is driven by technological innovation,” Stanford concludes.

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Transport, Logistics, Vehicles & Equipment

Locally built

trucking excellence

KwaZulu-Natal-based intermodal logistics expert Transgroup Logistics has added four FAW 16.240FT truck tractors and one FAW 15.180FL to its fleet.

T

ransgroup Logistics owner and director Ker win Naidoo explains that the company is currently ser vicing a few global brands, which will see it running its FAW trucks in and around the province and from the Durban port to Gauteng.

“We are doing local and national deliveries, and these vehicles are ideal for this purpose. The trucks are all single-axle vehicles, which means they are the right choice for light container loads,” explains Naidoo.

“These vehicles don’t come with computer boxes so they’re not highly technical in nature and are not difficult to maintain. We expect that downtime will be limited. Also, spares are readily available and FAW has ser vice dealers right along the N3. This makes it even easier for us.”

The company also undertook a study to determine what the most economical trucks would be when it came to light container loads. “That is why we chose FAW. Diesel cost is your biggest factor in transport and these trucks are light on fuel,” says Naidoo.

According to Mike Williams, dealer principal, FAW Pinetown, fuel consumption on these vehicles is outstanding. “A lot of our customers, particularly those

companies that have been running premium European brands, use FAW trucks on their medium- to long-haul routes because our fuel consumption is highly favourable,” he explains.

Local is lekker Naidoo says it is impor tant that FAW assembles vehicles locally. “There are a number of Euro-spec vehicles in the countr y and, should anything break, you could wait weeks for parts to arrive. With FAW, parts are readily available – you can have them within a day or two – so downtime is limited.”

FAW SA has an established plant in Coega, Eastern Cape. “I’m always proud to mention that FAW SA has been in business here for over 23 years now. And, the fact that FAW SA made a R600 million investment in a truck plant in Port Elizabeth is a statement that indicates we are here to

stay. Many people want the assurance that the brand will still be around in two years’ time,” says Williams.

FAW Pinetown Transgroup Logistics purchased its trucks from FAW’s Pinetown branch, which has seen growth in excess of 20% per annum, year-on-year, with a large percentage comprising repeat business.

The most important thing for Naidoo is the after-sales support and the ser vice inter vals of the vehicles.

“We are quick to assure our customers that parts are not an issue and that we have a regular supply. FAW Pinetown’s current par ts stockholding equates to R2.1 million,” says Williams. FAW Pinetown has the ability to provide full backup and 24-hour breakdown assistance, with five fully qualified diesel technicians on staff.

A growing fleet

The fact that FAW SA made a R600 million investment in a truck plant in Port Elizabeth tells people we are here to stay. ”

Transgroup Logistics has been approved for the purchase of a further eight FAWs, including five FAW 33.420FTs. “We hope to grow our fleet further during 2018. Once we start running and testing the FAWs, then we will slowly increase their numbers in the fleet,” says Naidoo.

IMIESA April 2018

57

The ultimate in Tandem Compaction

Suitable for low vibration compaction work, TanGO is BOMAG’s tangential oscillation exciter system, developed using oscillating vibration technology.

Comprising a highly durable steel drum, BOMAG provides an additional wear warranty of 6 000 hours on the roller drum.

Bell Equipment offers a comprehensive range of BOMAG’s technology leading compaction and road building equipment solutions backed by an extensive support network in southern Africa, striving to provide you with the ultimate in after-sales service.

Strong Reliable Machines • Strong Reliable Support Tel: +27 (0)11 928 9700 • sales@bell.co.za Web: www.bellequipment.com

Transport, Logistics, Vehicles & Equipment

Municipal all-rounder delivers

T

he MST backhoe loader continues to gain ground in South Africa, with local distributor ELB Equipment reporting strong sales within the municipal and local government markets for the MST 542 model.

MST is a Turkish original equipment manufacturer and is well represented in Europe, Africa, and other leading markets.

“It’s big and powerful enough to be used on road projects, trenches, excavations and almost any other type of work that our government departments and municipalities may need,” explains Desmond van Heerden of ELB Equipment.

He adds, “Simultaneously, it’s simple enough to be ser viced and maintained internally if need be and offers a level of sophistication usually associated with considerably more expensive, toptier machines.”

MST 542 backhoe loader Engine Power Torque Operating weight Loading height Dumping height Max digging depth

4.4 ℓ Perkins 74.5 kW 410 Nm @ 1 400 rpm 8 800 kg 4 350 mm 2 970 mm 5 907 mm

The machine comes equipped with plugand-play hydraulics for accessories such as hammers, multipurpose buckets and augers. “Ample power on demand, easy-tooperate features, and a safe, modern and airconditioned cab make the MST a firm favorite among operators,” says Van Heerden.

Technical support and rebuilds To help ensure optimal utilisation, ELB Equipment provides operator familiarisation training, as well as technical courses for earthmoving artisans employed by public sector workshops, which includes

entrenching health and safety best practices.

Given current budget constraints, a number of municipal fleet managers are looking to extend machine life and ELB is also assisting here with refurbishment and rebuild programmes.

“Over more than 10 years, our MST backhoe loaders have represented the kind of versatility required by government with easy and uncomplicated operation, reliability, and low running costs. This has contributed to its success and continues to make it an ideal addition to any fleet,” concludes Van Heerden.

IMIESA April 2018

59

CLOSE TO OUR CUSTOMERS

For your success.

ROAD AND MINERAL TECHNOLOGIES. The WIRTGEN GROUP is a one-stop supplier of leading technologies encompassing the entire road construction cycle: From processing, mixing, paving and compaction back to rehabilitation. This is how close to our customers works, in the www.wirtgen-group.com/southafrica WIRTGEN GROUP. Find out more: www.wirtgen-group.com WIRTGEN SOUTH AFRICA (PTY) LTD. 52 Maple Street . Pomona . Kempton Park . 1619 . E-Mail: sales.southafrica@wirtgen-group.com

South Africa_WG_CAMPAIGN_6_BRANDS_220x130.indd 1

12.05.17 11:4

82ND IMESA CONFERENCE

31st October to 2nd November 2018 B OA R D WA L K H OT E L

PORT ELIZABETH

2018

INNOVATIVE INFRASTRUCTURE SOLUTIONS

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Cement & Concrete

Ride and comfort

C

oncrete roads suffer from an image problem because many old concrete pavements still in existence were designed long ago to very different design criteria compared to modern examples, says Bryan Perrie, managing director of The Concrete Institute.

Perrie says, decades ago, concrete roads were constructed using what are now regarded as obsolete equipment and techniques that negatively affect ride comfort. “Although safety has always been a major concern, ride and acoustic comfort were barely considered 40 years ago,” he explains.

“Modernised designs, new construction methods, better surface finishing and hightech machines mean that it is perfectly possible nowadays to realise high-quality concrete pavement surfaces that do indeed satisfy the needs and objectives of road users, communities who live near the pavements, as well as road managers.”

Surface evenness, characterised by longitudinal evenness and mega-texture, as well as rut formation, has a significant impact on the ride comfort of vehicle passengers.

“Early concrete pavements were perceived as being uncomfortable to ride on because of the widths of the joints and faulting

Advances in pavement methodologies now make a strong business case for concrete roads.

However, this hasn’t always been the case. at the joints due to a lack or loss of load transfer, or because of localised damage to supporting layers that contained material susceptible to erosion. However, since the early 1970s, this problem has been dealt with by modified concrete pavement design.” says Perrie.

Construction techniques According to Perrie, these solutions included: • shorter slabs of concrete (minimum 4 m long) that make the pavement less prone to cracking • narrow contraction joints that limit the joint nuisance to a minimum • dowels in the transverse joints and cement-bound bases that ensure excellent load transfer and no longer allow any level differences at the joints.

“Continuously reinforced concrete is often chosen for motorways and primary roads, as this form of construction does not feature transverse joints. The shrinkage of the concrete is absorbed by a pattern of narrow,

The use of colour in concrete roads can help alert motorists to traffic restrictions, such as dedicated BRT lanes

closely spaced cracks that have no impact whatsoever on the pavement’s evenness or ride comfort.”

Smooth concrete roads can now be built thanks to: • optimised concrete mixes with constant workability, prepared in modern computercontrolled mixing plants that are often set up on the site itself • new generations of slipform pavers equipped with automatic vibrator control systems • properly installed guide wires for controlling the machine or wireless systems that make use of total stations • the use of longitudinal levelling beams behind the finishing machine (“super-smoothers”) • new types of evenness measurement set up immediately behind the paver,

IMIESA April 2018

61

cement & concrete

thus allowing the correction of the construction process.

“Apar t from countries where studded tyres are allowed, concrete pavements are immune to rut formation. An important property of concrete pavements is that the longitudinal and transverse evenness obtained after construction is retained for many years,” he continues.

Visibility and safety When it comes to safety threats – such as skidding, aquaplaning and visibility – accidents can be prevented in both dry and wet weather by providing a good surface texture with sufficient sur face friction.

Concrete pavements’ capacity to counter skidding have been improved in recent years through fine exposed aggregate surfaces that show no significant decrease in skid resistance over time.

The texture of the pavement, combined with the transverse profile, has a major influence on the potential danger of aquaplaning, which happens when the tyres of the vehicle lose all contact with the

Modern concrete pavements are infinitely better, in many respects, compared to those produced decades ago

Noise suppression Concrete pavement traffic noise can be controlled through various means that include: • Using barrier walls that are particularly effective on pavements with heavy truck traffic • Building the roads an adequate distance away from people living in the vicinity • Controlling the noise at source at the pavement surface. In recent years, numerous noise-abating wearing courses have been developed and research and testing is still ongoing in many countries

pavement surface. As concrete surfaces do not form ruts, the likelihood of this is virtually non-existent if the transverse profile is given the correct super-elevation.

Transverse textures or exposed aggregate surfaces with sufficient texture depth will also substantially limit splash and spray coming from behind vehicles.

“The colour and texture of concrete pavements can also be varied to warn motorists of impending hazard situations,” Perrie concludes.

ENDING EROSION Technicrete Armorflex erosion control system provides an alternative for a wide variety of erosion control and drainage projects. When your project calls for protection that can withstand severe applications and climatic conditions, with quick installation with no in-situ concrete or even under water, Armorflex from Technicrete is the engineered solution.

Suitable for:

Specially designed:

•

•

• • • •

Rivers, Estuaries, Dams, Reservoirs Areas subject to wave action Access roads Parking areas Stormwater drift crossings

• • •

Compressed concrete blocks (solid or vertical holes

or horizontal cable ducts)

Interlocking system Partial taper of each block Various sizes of blocks available

paving | mining | masonry | erosion protection retaining walls | drainage | kerbs | precast products www.technicrete.co.za Technicrete is a subsidiary of ISG, a leading supplier of innovative infrastructure products to the construction and mining markets in Southern Africa.

Tel: 011 674 6900 Maxi call: 0861 266 267

Cement & Concrete

Testing done right Quality-control testing performed strictly according to national standards is vital to ensure quality readymix concrete on-site.

By Johan van Wyk*

T

he first step towards the acceptance of any readymix concrete is the slump test, making it one of the most important tests for readymix suppliers.

When it comes to performing any testing, sampling is probably the most important aspect; however, there are several aspects to consider when it comes to testing readymix concrete.

Testing has to be specified For readymix concrete, quality-control testing has to be specified, just like the other aspects on a construction project. Users of readymix concrete don’t always realise

this, unless otherwise specified. Readymix suppliers do process control testing for their own purposes and users should always specify further tests they require for their own purposes.

There is a vast difference between process control testing and quality-control testing to meet specifications on-site. As a norm, readymixers take samples at the plant and not necessarily at the point of discharge. Only one out of ever y 100 m3 is tested.

Know your tests It is important for specifiers to know the test specifications. The two most commonly

The slump test procedure, according to SANS 5862–1 is as follows: and inside 1 ofWipethetheconebasewithplate a damp cloth Place the cone in the middle 2 of the base plate on a firm,

level surface

Place feet firmly on the 3 foot-pieces Fill the cone in three equal 4 layers, using a funnel to

avoid spilling

Give each layer 25 blows with 5 the rounded end of the

tamping rod, making sure the rod goes into the layer below when tamping the second and third layers Level off the top by rolling the 6 tamping rod over the top of the cone

Clean the area around the 7 base of the cone on the top handles 8 ofPressthedown cone and remove feet

from the foot-pieces. Lift the cone slowly straight up, taking about five seconds

Turn the cone upside-down 9 and place it on the base plate

close to the concrete. Put the slump rod over the cone and measure from the bottom of the rod to the highest point of the concrete, to the nearest 5 mm

IMIESA April 2018

63

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Planning beautiful concrete? Our School of Concrete Technology offers the right courses for a perfect result.

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Cement & Concrete

used tests for acceptance of concrete are the slump and compressive strength tests.

For both of these tests, sampling is just one of the important factors to be considered. The specification for sampling clearly states that the sample should be taken from the middle 80% of the truck â&#x20AC;&#x201C; in other words, not from the first or last 10% of the readymix truck.

It is also important to let the truck spin and mix for at least five minutes before taking the sample, as this will ensure thorough mixing and a representative sample. The sample is then taken from a moving stream of concrete, by taking scoopfuls of concrete from the chute, until the required sample size is achieved.

The slump test The slump test should be done within 15Â minutes of taking the sample. SANS 878 also states that the slump test should be done within 30 minutes of the truck arriving on-site for the supplier to guarantee the required slump. If the concrete shows a shear or collapse slump, repeat the test. If the second

IMIESA April 2018

65

Cement & Concrete

slump test shears or collapses, record this in the relevant “Slump, mm” block, as ‘shear’ or ‘collapse’.

Report all sheared and collapsed slumps to the concrete technologist for corrective action, such as checking raw materials and/ or mix design.

Acceptance SANS 878 states that there is a permissible range for slump acceptance. For example, when a 90 mm slump is specified, the permissible range for acceptance is 25 mm above or below the specified slump. That means that for 90 mm specified slump, slumps from 65 mm to 115 mm should be accepted. The specifier can tighten this criterion, but remember that slump is measured

66

to the nearest 10 mm when specifying a smaller range for acceptance.

Training The laboratory assistants performing the tests must be well-trained on the testing of readymix concrete. They need to understand not only how to perform the test, but also the reason for the test and what it is that they need to achieve through the testing. This will ensure that testing takes a very high priority.

After all, the whole structure’s acceptance hangs on the quality of the testing done.

Word of warning The following five critical points need to be taken into account for the correct testing to be undertaken:

1. What is specified?

2. What are the acceptance criteria?

3. Who is going to do the testing?

4. Agree on the testing methods etc. before the project starts.

5. When planning to test, you have to plan how, where and when testing takes place.

What is important to know is that a test has many facets and, for the test to be accepted, every one of these has to be done according to SANS specification. If any one of these is not done, then one cannot determine the influence of any small inconsistency, so the outcome of the whole test is invalidated. *Johan van Wyk is the director of the Southern African Readymix Association (SARMA).

IMIESA April 2018

USE ONLY WHAT YOU NEED You can decrease your building project’s carbon footprint by using precast concrete.

Compared to cast-in-situ, precast uses less of everything – less cement, less water, and less steel.

The precast elements also have good insulation and thermal properties that decrease the total CO2 load of the building during its lifetime.

Elematic is the leading supplier of precast concrete production technology worldwide.

Ask us how to maximize the benefits of precast in your projects.

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PROFESSIONAL AFFILIATES AECOM siphokuhle.dlamini@aecom.com Afri-Infra Group (Pty) Ltd banie@afri-infra.com AJ Broom Road Products ajbroom@icon.co.za ALULA (Pty) Ltd info@alulawater.co.za AQUADAM (Pty) Ltd sales@aquadam.co.za Arup SA rob.lamb@arup.com Aurecon Fani.Xaba@aurecongroup.com Aveng Manufacturing Infraset cgroenewald@infraset.com Averda claude.marais@averda.com Bigen Africa Group Holdings otto.scharfetter@bigenafrica.com BMK Group brian@bmkgroup.co.za Bosch Munitech info@boschmunitech.co.za Bosch Projects (Pty) Ltd mail@boschprojects.co.za BVI Consulting Engineers marketing@bviho.co.za Civilconsult Consulting Engineers mail@civilconsult.co.za Corrosion Institute of Southern Africa secretary@corrosioninstitute.org.za Development Bank of SA divb@dbsa.org.za DPI Plastics mgoodchild@dpiplastics.co.za EFG Engineers eric@efgeng.co.za Elster Kent Metering Leonardus.Basson@honeywell.com ERWAT mail@erwat.co.za Fibertex South Africa (Pty) Ltd rcl@fibertex.com GIBB yvanrooyen@gibb.co.za GIGSA secretary@gigsa.org GLS Consulting nicky@gls.co.za Gudunkomo Investments & Consulting info@gudunkomo.co.za Hatch Africa (Pty) Ltd info@hatch.co.za Henwood & Nxumalo Consulting Engineers cc pmboffice@hn.co.za Herrenknecht schiewe.helene@herrenknecht.de Huber Technology cs@hubersa.com Hydro-comp Enterprises dan@edams.co.za I@Consulting louis_icon@mics.co.za INGEROP mravjee@ingerop.co.za Integrity Environment info@integrityafrica.co.za IQHINA Consulting Engineers & Project Managers info@iqhina.co.za iX engineers (Pty) Ltd hans.k@ixengineers.co.za JBFE Consulting (Pty) Ltd issie@jbfe.co.za JG Afrika DennyC@jgafrika.com KABE Consulting Engineers info@kabe.co.za Kago Consulting Engineers kagocon@kago.co.za Kantey & Templer (K&T) Consulting Engineers info@kanteys.co.za Kitso Botlhale Consulting Engineers zimema.jere@gmail.com Knowledge Base info@knowbase.co.za Lektratek Water general@lwt.co.za Lithon Project Consultants (Pty) Ltd info@lithon.com Makhaotse Narasimulu & Associates mmakhaotse@mna-sa.co.za Malani Padayachee & Associates (Pty) Ltd admin@mpa.co.za M & C Consulting Engineers (Pty) Ltd info@mcconsulting.co.za

Maragela Consulting Engineers admin@maragelaconsulting.co.za Marley Pipe Systems info@marleypipesystems.co.za Martin & East gbyron@martin-east.co.za Masithu Consulting & Project Management info@mcpm.co.za Mhiduve adminpotch@mhiduve.co.za Mogoba Maphuthi & Associates (Pty) Ltd admin@mmaholdings.co.za Moedi Wa Batho Consulting Engineers (Pty) Ltd info@wabatho.co.za Mott Macdonald Africa (Pty) Ltd johannesburg@mottmac.com Much Asphalt bennie.greyling@muchasphalt.com NAKO ILISO hans.hartung@nakogroup.com Nyeleti Consulting ppienaar@nyeleti.co.za Odour Engineering Systems mathewc@oes.co.za Pumptron info@pumptron.co.za Royal HaskoningDHV francisg@rhdv.com SABITA info@sabita.co.za SAFRIPOL mberry@safripol.com SALGA info@salga.org.za SARF administrator@sarf.org.za.co.za SBS Water Systems mava@sbstanks.co.za Sembcorp Siza Water info-sizawater@sembcorp.com SiVEST SA garths@sivest.co.za Sizabantu Piping Systems (Pty) Ltd gregl@sizabantupipingsystems.com SKYV Consulting Engineers (Pty) Ltd kamesh@skyv.co.za SMEC capetown@smec.com SNA stolz.j@sna.co.za Sobek Engineering gen@sobek.co.za Southern African Society for Trenchless Technology director@sasst.org.za Southern Pipeline Contractors (Pty) Ltd spc@vinci-construction.com SRK Consulting jomar@srk.co.za Syntell julia@syntell.co.za TPA Consulting roger@tpa.co.za Ulozolo Engineers CC admin@ulozolo.co.za UWP Consulting nonkululekos@uwp.co.za V3 Consulting Engineers (Pty) Ltd info@v3consulting.co.za Vetasi south-africa@vetasi.com VIP Consulting Engineers esme@vipconsulting.co.za VUKA Africa Consulting Engineers info@vukaafrica.co.za Water Institute of Southern Africa wisa@wisa.org.za WAM TECHNOLOGY CC support@wamsys.co.za Water Solutions Southern Africa ecoetzer@wssa.co.za Wilo South Africa marketingsa@wilo.co.za WRP ronniem@wrp.co.za WRNA washy@wrnyabeze.com WSP Group Africa sam.herman@wspgroup.co.za

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