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PRECAST VOLUME SEVEn ISSUE 2 • 2013

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the cma – QUaLItY caSt IN cONcRete

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• CMA footprint extends north of the Limpopo

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• Phumelela municipality chooses concrete block paving

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• Cape Town sea wall rehabilitated

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ConTEnTS

1

precast contents nEWS 2

nEW CMA oPERATInG STRUCTURE

2

UPDATED MBA noRTH DIRECToRY

3

ConCRETE InSTITUTE REPLACES C&CI

4

AFRISAM PRoTECTS RARE FAUnA

24 BoSUn InTRoDUCES nEW PAVInG FInISHES 25 PMSA InTRoDUCES MoBILE BRICk MAkInG MACHInES To AFRICA 26 TECHnICRETE PAVERS USED AT MAHWELEREnG SHoPPInG CEnTRE

AnD FLoRA

PRECAST VOLUME SEVEn ISSUE 2 • 2013

5

CMA’S STAnD AT ToTALLY ConCRETE

A section of a rehabilitated sea wall at Three Anchor Bay, Cape Town, where precast concrete panelling, coping, bollards and paving blocks (CPB) are being used for phase 1 of the Mouille Point Sea Wall Rehabilitation Project. Begun in november 2012, it is due for completion in February 2015 and entails rehabilitating a 600m section of sea wall and promenade from Three Anchor Bay to the Mouille Point Lighthouse. m

PAYS DIVIDEnDS

ON THE COVER

the cma – QUaLItY caSt IN cONcRete

a

nu

facturer

s

as

PRECAST ConCRETE REPLACES GRAnITE In SEA WALL REHABILITATIon

ncrete

co

n

6

iatio

ARTICLES

• CMA footprint extends north of the Limpopo

soc

• Cape Town sea wall rehabilitated

• Phumelela municipality chooses concrete block paving

Q

ua

lity

cast in conc

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12 PHUMELELA MUnICIPALIT Y oPTS FoR ConCRETE BLoCk PAVInG 15 CMA MEMBERSHIP EXTEnDS noRTH oF THE LIMPoPo 18 ConCRETE BLoCk PAVInG – An IDEAL ALTERnATIVE To ASPHALT RoADS

PRECAST is the official journal of the Concrete Manufacturers Association (CMA) 16 Horn Street, Chloorkop, kempton Park, 1620 Postnet Suite 8612, Private Bag X32, kempton Park, 1620 Tel: +27 11 805 6742, Fax: +27 86 524 9216 E-mail: admin@cma.org.za, Website: www.cma.org.za Publishers Isikhova Publishing & Communications Po Box 651793, Benmore, 2010, South Africa Tel: +27 11 883 4627, Fax: +27 11 883 4627 Website: www.isikhova.co.za

APPLICATIonS

Publisher: Andrew Meyer Tel: +27 11 883 4627, Cell 082 456 5175

20 EnHAnCED ConCRETE WoRkABILIT Y 21 REMACon LAUnCHES FREE-STAnDInG BULk-SToRAGE SYSTEM 21 BoSUn InCREASES kERB MAnUFACTURInG CAPACIT Y

E-mail: andrewm@isikhova.co.za Editor: David Beer Tel: +27 11 478 0239, Fax: +27 11 678 0254 E-mail: bigsky@ibi.co.za Advertising: Andrew Meyer Tel: +27 11 883 4627 E-mail: communications@isikhova.co.za Design, layout and production: Joanne Brook Tel: +27 11 883 4627 E-mail: joanne.studio@isikhova.co.za

23 PRECAST ConCRETE PoLES REPLACE VAnDALISED STEEL PoLES 24 LonG-STAnDInG RETAInInG WALLS EXTEnDED WITH TERRAFoRCE BLoCkS

The views and statements expressed in this publication are not necessarily those of the editor or the publishers and neither he, the publishers nor the CMA accept responsibility for them. no person connected with the publication of this journal will be liable for any loss or damage sustained as a result of action following any statements or opinions expressed herein.

PRECAST VOLUME 7 • ISSUE 2 • 2013


2

nEWS

NeW cMa OperatING strUctUre UNrOLLeD at aGM The CMA’s new operational structure was

split into two working categories, Precast

membership was restricted to certain

officially launched during this year’s annual

Building and Precast Infrastructure.

categories of precast concrete producers,

He also explained how the Association

the Association was now open to all

o ver 30 people attended and the

w a s c o p ing un d e r di f f i c ul t f in an c i al

precast concrete manufacturers providing

following office bearers were confirmed:

circumstances now that it was no longer

they met certain quality criteria.

executive director, Wally Armstrong;

being funded by cement producers through

other initiatives included the estab-

technical director, Taco Voogt; and financial

the former C&CI. Several economising

lishment of working chapters in the major

director, John Simpson.

m e asur e s su ch as m o v ing in t o n e w

centres and a panel of experts was being

premises were bearing fruit.

established to assist producer members

general meeting.

T he meeting was chaired by Wally Armstrong and he and his two fellow

He mentioned further that a drive

with technical queries.

for new members had yielded eight new

A rmstr ong noted that the CM A’s

Armstrong gave an overview on the

members, more than one a month, and

largest asset was its library of technical

status of the Association and noted that

that membership was expected to increase

literature which of f ered guidance on

the CMA brand was very strong and widely

substantially in kwaZulu-natal and the

different types of precast concrete and

respected. In future its activities would be

Eastern Cape. Unlike in the past where

their applications and that many of its

directors addressed the meeting.

publications are now due for revision. Voogt spoke about the importance of maintaining the CMA’s close working relationship with the South African Bur eau of Standar ds in r ev ising and establishing standar ds f or construction. He also touched on sk ills training issues and masonry thermal efficiency (hot box) testing which had been jointly sponsored with the C&CI. Simpson gave a detailed breakdown of the Association’s financial status and said that provided the new recruitment drive went according to plan the prospects for CMA executive director, Wally Armstrong, addresses the CMA AGM.

UpDateD MBa NOrtH DIrectOrY Master Builder Association north has

bearers, benefits of membership, and

published an updated version of its new

alphabetic as well as categorised member

directory of members and services which

listings. It also contains supplier listings,

was launched last year.

and comprehensive advice on building

T he MBA nor th 2013 directory is

matters for the property owner. Included

available in a handy and compact

in these advisory articles are guidelines

A5 format. It is aimed at the general

on getting the best out of your building

public as well as current and prospec-

contractor, moving into a new or newly

tive new MBA members, says Wesley

altered house, and advice on avoiding

Soutter, commercial and legal director of

building disasters.

MBA north.

“The new directory forms part of a

“We felt that there was a need for

series of building publications we are

a pr in ted dir ec tor y to augmen t the

planning to improve communications,”

membership listing already available on

Soutter added.

our website. The 2012 directory proved

To obtain a copy of free directory,

ex tr emel y popular and we upda te i t

contact Donique at the MnBA north

annually,” he adds.

offices in Midrand on 011 805 6611/ 086

The booklet contains details of office

PRECAST VOLUME 7 • ISSUE 2 • 2013

162 2667 or email info@mbanorth.co.za.

the CMA looked promising.


nEWS

3

cONcrete INstItUte repLaces c&cI Three of South Africa’s leading cement producers have stepped in to f und the establishment of a new institute to preserve the vital education, and consulting services previously provided by the Cement & Concrete Institute (C&CI). AfriSam, Lafarge and Sephaku are now financing the operations of The Concrete

Bryan Perrie, MD of The Concrete Institute.

Institute which, from May 2 this year, started providing most of the major services previously offered by the C&CI. The latter closed down at the end of April 2013 following the withdrawal of funding. Bryan Perrie, former MD of the C&CI, is in charge of The Concrete Institute, a non-profit company with a number of key members of the C&CI staff retained. The Concrete Institute will offer vital concrete technology services to the construction industry, including: • Education and training • Information centre • Consulting • Publications. Perrie says all the courses listed in the C&CI’s School of Concrete Technology 2013 Training Programme are still being offered. “We are, in fact, hoping to expand the curriculum by including even more courses. The Concrete Institute has also taken over the responsibility for running the comprehensive and highly-respected Advanced Concrete Technology course which was underway when C&CI closed.” The Concrete Institute is also offering a free advisory service as well as chargeable consulting services, including on-site visits by technical staff. The institute will continue to of fer a comprehensive information centre. Equipped with top specialists and state-ofthe-art computerised systems, the centre is one of the largest and most respected sources of information on concrete in the southern hemisphere. It will also distribute the wide range of C&CI publications. “There was widespread dismay within the building and construction industries when the C&CI was forced to close its doors. With the support of new cement producer, Sephaku, as well as the continuing support of AfriSam and Lafarge, we are now confident that the Concrete Institute will continue to provide the services which made the C&CI an industry icon over the past 75 years,” Perrie added. “The new Institute also aims to play a wider role and work more closely with, and provide assistance to, other building and construction bodies and establish reciprocal working arrangements with these organisations.” The Concrete Institute operates from Block D - Lone Creek, Waterfall Park, Bekker Street in Midrand. It can be reached on telephone 011 315 0300 or fax 011 315 8180.

PRECAST VOLUME 7 • ISSUE 2 • 2013


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nEWS

aFrIsaM prOtects rare FaUNa aND FLOra It is now widely recognised that con-

one of the most impor tant South

over 500 hectares for conser vation,

ser vation cannot be confined to land

African conservation sites is situated on

which has been classified as Contract

owned by statutory conservation bodies.

the Saldanha Peninsula in the Western

nature Reserve status – the highest level

For this reason, Stewardship has become

Cape. Classified as Saldanha Limestone

of Stewardship.

integral to the country’s conservation of

Strandveld, it contains pristine vegetation

In addi tion, as p ar t o f A f r iS am’s

fauna and flora for future generations.

of exceptional conservation value which

corporate social responsibility programme,

Stewardship involves the protection of

is only found on the Peninsula. Because

the comp any pr o v ided bur sar ies f or

plant and animal species on privately

it grows on a unique substrate, the

students from Saldanha communities

owned land by restricting development.

vegetation type contains several unique

to study natural resource management

plant species. Classified as Endangered

at the South African Wildlife College.

by the nBSA these species cover a mere

After completing their studies two of the

0.1% of the land. Small patches are also

students, nolan Stevens and Suzette

found in the West Coast national Park.

Pieters, were employed by AfriSam in

Par t of the Saldanha Limestone Strand veld is owned by Af riSam and

7980/E

An example of the vegetation type found on Saldanha Limestone Strandveld which is restricted to the Saldanha Peninsula.

2010 to conserve the site and protect its valuable plant species.

the site has been earmarked for the

AfriSam has also partnered with the

construction of a cement factory once

Cape West Coast Biosphere Reserve,

a full environmental impact analysis has

which is responsible for supervising the

been completed. As a demonstration

two graduates as well as assisting with

o f A f r i S a m ’s c o m m i t m e n t t o t h e

the general management and conservation

environment, the company has set aside

of the site.


nEWS

producer members. These were: Echo Precast; Coverland; Style Decor; Southern Pipe-

5

Peter Kernick, managing director of FastDeck in Botswana seen here with Monique Eggebeen, managing director of Echo Prestress, at the CMA stand.

line Contractors; The Bosun Group; Concrete Units; FastDeck (Botswana); and ReMaCon. CMA executive director, Wally Armstrong, said that many of the visitors expressed an interest in joining the AssoThe CMA’s stand at Totally Concrete 2013,

ciation especially as the CMA is now open

held at the Sandton Convention Centre, at-

to all precast concrete manufacturers.

tracted a steady stream of visitors, reflect-

“The interest shown by prospective

ing a high level of interest in the Association.

new members in joining our ranks is most

The exhibition was held during the first

encouraging and bodes well for the future.

week of June and the CMA stand was jointly

So far this year we have signed on eight

sponsored by the CMA itself and eight of its

new members.”

Mark Heap (left), managing director of Conframat, and CMA executive director, Wally Armstrong, at Totally Concrete 2013.

POSSIBILITIES THAT CONNECT A CITY AT AFRISAM WE DON’T JUST BUILD BRIDGES, WE DEVELOP SOLUTIONS THAT CREATE POSSIBILITIES. Take our involvement in the Nelson Mandela Bridge in Newtown where we pumped our Flowcrete into the 47m pylons from the bottom upwards - a process never before attempted. The bridge spanning over 8 railway tracks now connects an entire city.

www.afrisam.co.za With the planet as one of our core values, we measure the carbon footprint of each and every one of our operations and products while actively striving to drive down our impact on the environment.


6

ARTICLE

Granite blocks removed from the sea wall and stockpiled for re-use as pedestrian seating.

precast cONcrete repLaces GraN Precast concrete panelling, coping, bollards and paving blocks (CPB) have been specified by the City of Cape Town Municipality for Phase 1 of the Mouille Point Sea Wall Rehabilitation Project.

footpath behind the wall, and the construction of a splash wall on the landward side of the promenade footpath using the granite blocks removed from the sea wall.

Begun in november 2012 the project is due

concrete core and the subsequent erosion

one of the purposes of the splash wall is

for completion in February 2015 and entails

of backfill material. The loss of fill material

to prevent sea water from reaching the

rehabilitating a 600m section of sea wall

under the paved footpath led, in places, to

grassed area behind it if the sea wall is

from Three Anchor Bay to the Mouille Point

the collapse of the latter.

over-topped. Re-laying of the footpath is

Lighthouse and renewing the promenade above it using CBP and other materials.

T he r ehabili t a tion pr oje c t en t ails strengthening and re-facing the sea wall

taking place in the sections where the wall has been rehabilitated.

E x tensive research into the most

with special emphasis being paid to the

suitable materials, both for the sea wall

durability of its various components. It

Rehabilitating the sea wall

and the promenade, was conducted by

also involves re-paving of the promenade

Besides creating a promenade, the original

consulting engineers, Ingérop South Africa,

sea wall was built to keep back kelp and to

in collaboration with the City of Cape Town.

facilitate the disposal of solid waste. The

Dressed with granite blocks when it was

rehabilitated wall comprises fresh material

first built during the 1920s-1940s, the wall

such as the concrete panelling and new

has successfully withstood the full force of

coping as well as parts of the existing

the Atlantic for over 70 years. However,

structure such as the original foundation

continual exposure to wave action meant

and its mass concrete core.

that sea water eventually eroded the

Precast panelling, measuring 2.5m x

mortar jointing and dislodged some of the

1.2m and manufactured by CMA member,

blocks, penetrating the concrete behind them. This led to the exposure of the wall’s

PRECAST VOLUME 7 • ISSUE 2 • 2013

A section of precast cladding seen here adjacent to a section of the old granite wall facing.

Concrete Units, was chosen to dress the new wall for several reasons, cost and time


ARTICLE

A completed section of sea wall at three Anchor Bay showing the precast cladding and new coping.

7

Recently installed precast concrete cladding prior to the pouring of concrete between the cladding and the existing wall.

NIte In seA WALL ReHABILItAtIon saving being major considerations. The

was done to give the new wall a similar look

panels are 125mm thick and consist of a

and feel to the old structure while simul-

30% fly ash blend. Reinforced with hot-dip

taneously improving overall performance.

galvanised rebar and rated at 50MPa, the

The wall reconstruction process begins

panels satisfy the minimum design service

by removing and palletising the existing

life of 50 years.

concrete block paving for re-use and

As City of Cape Town engineer and

excavating the backfill of the original wall

Mouille P oin t pr ojec t manager, P aul

down to the existing footing. The exposed

Vink, observes, rehabilitating the wall is

wall area is then thoroughly cleaned using

complicated by intermittent wave action

high-pressure water jetting to remove

which shortens the period in which actual

loose material and debris.

construction work can take place.

The new in-situ reinforced concrete

“Therefore any process which saves

backing is 400mm thick and rated at 25MPa.

tim e is a d v an t age o us an d c on cr e t e

However, before the backing concrete can

panelling obviously meets this objective.

be poured, all horizontal fissures in the

Another benefit is that, unlike granite

existing wall are sealed against grout loss

facing, precast concrete panelling has

and sea water penetration. In addition,

a limited number of joints for the sea to

galvanised Y12 dowels, as shown in the

landfill and allows controlled compaction of

penetrate. Furthermore, because precast

cross sectional diagram, are inserted and

the backfill to form the new base for the

concrete is produced to strict quality

grouted into ø18 holes drilled 250mm deep

promenade paving.

controls in a factory environment, it will

into sound concrete at a horizontal spacing

provide the durability required.”

of 600mm.

Three Anchor Bay, where a section of walling has been prepared for the installation of precast concrete cladding. Galvanized dowels, which will support the panels, are clearly visible.

once this process is completed the existing coping and granite f acing is

The moulds for the panelling were made

Furthermore, excavation permits the

removed. Where possible, reinforcement

using granite samples from the old wall. This

removal of unsuitable material from the old

which is exposed during the demolition of

PRECAST VOLUME 7 • ISSUE 2 • 2013


8

ARTICLE

the coping is straightened and cleaned to

to pave 10 trial sections during the early

be re-used with the new coping. However,

part of 2010.

if this reinforcement is deemed inadequate

The promenade section chosen for the

by the engineer, additional Y16 galvanised

trial panels was exposed to regular wave

dowels are inserted into the concrete core.

action, unlike other sections which were

The exposed concrete of the existing

more sheltered. Because of this results

wall is then thoroughly cleaned, once

could be obtained within a relatively short

again using high-pressure water jetting to

test period of 19 months.

remove loose material and debris. next,

A ll 10 trial panels wer e unif ormly

the top of the original foundation is levelled

exposed to wet and dry cycles of the

with a screed and 400mm long galvanised

marine environment and normal pedestrian

dowels are inserted into what remains of

traffic. The exposure to sea water led

the wall and grouted. After the grouting

to a high incidence of algae growth and

has set the concrete panels are placed

discolourisation on some of the panels, and

into position and secured.

the effects on the safety of these panels

Some of the paving block trial sections.

The precast panels act as permanent

was significant. The clay brick panels (TP5

the partial washing out of the jointing sand

shuttering, and once installed using a

and TP7 see Table-1) were particularly

which reduced the interlocking effects of

mobile crane, high- strength, marine-grade

slippery when wet and posed a serious

the adjacent pavers. This too could have

concrete can be poured into the space

safety hazard to pedestrians.

been hazardous for pedestrians if the process had been allowed to continue.

between them and the wall, with particular

Some differential settlement between

care being paid to prevent voiding in the

individual paving blocks was also visible on a

Although there was no settlement or

concrete infill. All joints between adjoining

few of the panels. The probable cause was

collapse across any of the trial panels,

panels are then grouted solid with a shrinkage compensated cementitous grout which attains a compressive strength exceeding that of the precast panels within three days. new 1.2m wide pr ecast concr ete coping blocks, each weighing 1 400 kg, are then installed on top of the new wall and concreted into position by filling the preformed cavities with a 50% GGBS blend of 40MPa concrete. This is followed by the installation of new precast concrete posts into ready-made cavities in the coping and grouted into position. In keeping with the durability critical aspects of the design, the posts are manufactured using 40MPa fibre-reinforced concrete. All metallic reinforcement other than the stainless steel anchors was omitted. The newly completed wall thus presents an effectively homogenous barrier to the extreme marine conditions and should equal or surpass the proven durability of the original wall. Renewing the prominade paving The City of Cape Town conducted trials on 10 different paving materials to establish which would be the most suitable in terms of safety, aesthetics, durability, maintenance, marking or staining, and comfort. Eight concrete block paving producers and two clay brick manufacturers, were invited

PRECAST VOLUME 7 • ISSUE 2 • 2013


ARTICLE

9

several of the concrete block pavers

mix, lack of uniformity in the production

less obvious on two concrete aggregate-

showed signs of significant surface damage

processes and other quality control issues

type paving test panels (TP8 and TP10).

and/or degradation.

were identified as the main causes of

Bob Smith, senior designer and resident

“By contrast the clay brick pavers showed no signs of surface damage or

surface degradation.

engineer of Ingérop South Africa, says that

“Concrete pavers are generally prone to

degradation and were unlikely to do so

over the years concrete pavers in marine

some degree of surface damage and degra-

due to the inherently high strength of

environments have been the subject of

dation. This was quite visible on two of the

kiln-fired clay products and uniformity in

several performance trials during which

concrete trial panels (TP4 and TP6) in what

the production processes.

poor design and control of the concrete

was initially a smooth surface finish and

“However, as this trial revealed, clay pavers are more susceptible to algae growth and discolouration, especially on the

TABLE 1 – Summary of Conclusions

side closest to the sea. This was possibly

Test Criteria

TP 1

TP 2

TP 3

TP 4

TP 5

TP 6

TP 7

TP 8

TP 9

TP 10

Safety

Poor

Poor

Good

Good

Good

Good

Poor

Good

Good

Good

Aesthetics

Good

Good

Fair

Good

Good

Good

Poor

Good

Good

Good

Durability

Good

Good

Good

Poor

Fair

Good*

Good

Good**

Good

Fair**

Long-term Maintenance Stain Resistance

Fair

Fair

Poor

Good

Fair

Good

Fair

Fair

Fair

Fair

Fair

Fair

Poor

Fair

Good

Good

Good

Good

Good

Good

Comfort

Good

Good

Fair

Good

Fair

Good

Good

Fair

Fair

Fair

Suitability

Poor

Poor

Fair

Good*

Fair

Good*

Poor

Fair

Fair

Fair

due to the low permeability of clay paving which inhibits the free drainage of surface water and creates an environment which promotes algae growth.” Based on the findings of the survey, smooth interlocking concrete pavers, manufactured by CMA member, C.E.L. P a v i n g, w e r e s e l e c t e d t o b e u s e d throughout. A blend of natural colours was chosen which will be enhanced with coloured inlays, and borders where necessary. The 70mm thick topped pavers contain a

14


ARTICLE

11

Chryso Pareflo 20 waterproofing admixture

wet, they pose a significant danger to

raw materials. This ensures a reliable

in the topping and base and comply with the

pedestrians either during periods of heavy

long-term supply of pavers to match and

requirements of Class 40/2.6 pavers in the

seas or winter rains.

replace worn, broken or stained pavers.

new SAnS 1058:2012 standard. The paving is being laid on a 25mm sand

Aesthetics

Staining

bedding and 200mm gravel sub-base by

The Sea Point promenade is most popular

The smooth wearing surfaces of concrete

Exeo khokela’s in-house paving teams and

during the hot summer months when

pavers, formed face-down in a mould,

drainage is effected by the careful control

people are drawn to its cool and refreshing

are denser and thus less absorbent than

of cross falls.

environment. This perception is usually

struck or cut concrete surfaces and are

enhanced by the use of concrete paving’s

less susceptible to marking or stains.

The following criteria were used by IngĂŠrop and the City of Cape Town in

lighter greys and white tones.

reaching the conclusions summarised in Table 1.

Comfort Durability

Although this aspect is largely subjective

While surface degradation is clearly an issue

and will vary from user to user, the smooth

Safety

on some smooth concrete pavers, it is one

surfaces and interlocking properties of

Concrete block pavers have been used

that can be addressed through the use of a

shaped concrete block paving are generally

extensively along the promenade and

topped paver with proper quality control and

perceived as being the most comfortable

have a good safety record in a marine

assurance. other qualities also outweigh the

to pedestrian and wheeled traffic such

en v ir o nm en t . T h e sm o o th, in d en t e d

apparent durability advantages of clay brick

as baby strollers and wheelchairs. The

surfaces of concrete interlocking blocks

and exposed aggregate concrete pavers.

smooth surface is also more forgiving than

are not slippery when wet and provide a

exposed aggregate pavers which are far

good balance between grip and comfort.

Maintenance

more abrasive and likely to cause more

Because clay bricks were susceptible to

Concrete pavers are readily available

serious injury to people who may fall on

algae growth and were more slippery when

and manufactured from widely available

the promenade.

P


12

ARTICLE

pHUMeLeLa MUNIcIpaLItY oPts FoR concRete BLocK PAVInG Phumelela (formerly Vrede) Municipality is one of many local authorities which values the benefits of concrete block paving (CBP). It began using CBP eight years ago, paving the low-income suburb of Thembalihle. Since then 35% of the streets in and around Thembalihle have been paved with CBP and the project will continue until they are all surfaced with CBP.

One of the roads being paved with concrete block paving in Thembalihle, Phumelela.

Supplied by CMA member, Bosun Brick, the paving blocks are 80mm thick and are rated at 25MPa. Bosun also supplied the precast concrete kerbing blocks which are being used to construct openchannel drainage. Bonginkosi comments that the road

According to the project’s roads Resident

surfaces were built as flat as possible and

Engineer (RE), Sibeko Bonginkosi of Flagg

cross falls were kept to two percent to

Consulting Engineers, CBP rather than

ensure good drainage.

asphalt was specified for several reasons:

Comparing the maintenance costs of

long life spans and low maintenance;

CBP with asphalt, Bonginkosi says that

the easy construction of traffic calming

in the case of asphalt allowance must

features; aesthetic designs and greater

be made for filling in cracks as soon as

visual appeal; job-creation opportunities;

they occur to avoid water infiltration and

and the fact that CBP, unlike asphalt, does

further deterioration.

not use crude oil as a raw material.

“Asphalt requires surface dressing to A section of Hospital Road in Phumelela which has been paved with concrete block paving.

restore skidding resistance every five to

the blocks are being laid by four sub-

compacted to 95% mod AASHTo density

strengthened, especially when wheel ruts

contractors each employing 20-30

(G7) (middle layer); and 150mm in-situ

reach or exceed 10mm.

w o r k e r s, m o s t o f th em T h emb alihl e

road bed compacted to 90% mod AASHTo

residents. Ramutsa Rail is handling the

density (G10) (bottom layer).

T he r o ads ar e being constr uc ted by main contractor, Ramutsa Rail, and

earthworks, which in addition to grading

These layers were compacted to:

seven years. Moreover, overlays must be

“By contrast the maintenance costs f or well-constr uc ted CBP r oads ar e generally low. occasionally it is necessary

and levelling, involves the construction of

• Increase load-bearing capacity

to replace small numbers of concrete

the foundation material.

• Prevent soil settlement and

blocks. For example, those damaged

Four hundred and fif ty millimetres

frost damage

by container handling operations or by

thick, the CBP foundation comprises:

• Provide stability

the slewing of tracked vehicles. CBP is

150mm stabilised gravel sub-base (C4)

• Reduce water seepage, swelling

often selected where severe differential

compacted to 97% mod A ASHTo (top layer); 150mm selected upper sub-grade

PRECAST VOLUME 7 • ISSUE 2 • 2013

and contraction • Reduce soil settling.

settlement is expected. This can require lifting the pavers, restoring the road-base


ARTICLE

13

and relaying the pavers,” says Bonginkosi.

more, the initial capital outlay on CBP

In addition to the Thembalihle CBP

roads is only marginally greater than the

project, a dual carriage-way, comprising

asphalt equivalent. It therefore makes

two paved sections each measuring 480m

sense for all new urban road projects

long and five metres wide has recently been

to be surfaced with CBP. The saving on

completed on Hospital Road in Phumelela.

maintenance is huge and quickly offsets

The two sections are separated by an edge

any higher capital spend.

beam which is filled with earth for growing

“In addition, laying roads with concrete

flowers and shrubs. This road was built by

block paving is labour intensive and offers

the same professional team using the same

the unskilled and unemployed an opportunity

construction methods as those deployed

of acquiring a marketable skill and earning

at Thembalihle.

capacity. T he income earned on CBP

CMA technical director, Taco Voogt

projects has a multiplier effect, stimulating

says that most local governments are

economic activity in other sectors of local

under severe budget constraints and in

communities.

many cases are unable to maintain their

“Then there is the safety aspect. CBP

existing road networks, which are largely

offers better braking owing to its rough

paved with asphalt.

texture and broken surface. In addition

“We also know that CBP is essentially

it provides better road marking with

maintenance-free provided it is laid in compliance with best practice standards and this is why so many municipalities are opting for CBP for urban roads. What’s

coloured and luminous concrete pavers. Resident roads engineer, Sibeko Bonginkosi of Flagg Consulting Engineers, poses on one of the concrete block paving roads under construction in Thembalihle, Phumelela.

And the chance of aquaplaning on wet surfaces is greatly reduced with CBP roads,” concludes Voogt.

P


ARTICLE

cMa MeMBersHIp eXtenDs noRtH oF tHe LIMPoPo

15

stressing blocks, a fully equipped workshop and 1 800 metres of moulds. Its propless T-Beam system can be used over clear spans up to 12 metres, with beam depth, and load capacities being dependent on spans. View on www.bassbeams.com or contact Themba Hwalima on 031 784 1920 or via themba@bassbeams.co.za. Colonial Stone Founded in 1998 and based in Honeydew, Roodepoort, Colonial Stone prides itself on

The Concrete Manufacturers Association (CMA) has signed on eight new precast concrete members: Bass Beams; Colonial Stone; Delta Bloc; FastDeck (Botswana); namib Roof Tile Company (namibia); Style Décor; Tjeka Training Matters; and Vaka Concrete (Zimbabwe).

producing high quality, highly engineered

CMA executive director, Wally Armstrong,

“Some of our other current initiatives

surface pigmentation.

says that the grow th in membership

include training and the maintenance and

Colonial Stones’ products have excellent

stems from broader qualification criteria.

setting of national standards through the

tensile strength and their MPa ratings

simulated stone paving, tiling, cobbles and cladding. The company uses the best quality sand, cement and imported oxides. All its products are made with embodied colour throughout and don’t exhibit any

“The Association has been streamlined

SABS. We are also encouraging emerging

average between 40 and 50. The company’s

into two operating pillars, Precast Building

manufacturers to join the Association,

moulds are complex and its masters

and Precast Infrastructure. Unlike in the

as we believe existing member s can

exceptionally precise. Moreover, research

past when membership was dependent on

assist them in becoming f ir st class

and development is conducted using state-

fitting in with one of the former six product

precast concrete manufacturers,” says

of-the-art engineering equipment and C&C

categories, it is now open to any precast

Armstrong.

machinery. View on www.colonial-stone.

manufacturer, provided certain qualitybased criteria are met. And although

outlined below are brief profiles of some of the new members.

co.za or contact Friedel Weihe on 011 794 9737 or via alison@colonialstone.co.za.

our membership has always been open to companies north of the Limpopo we are

Bassbeams

now actively recruiting members from

Serving the entire kZn region, Bassbeams

countries such as Botswana, namibia,

is based in Cato Ridge, Durban. During the

Zambia and Zimbabwe, and we even hosted

past 30 years the company has produced

a delegation from kenya recently.

pr ecast /pr estr essed self-suppor ting

“As indicated above, three of our new

suspended concrete floors and struc-

members are based north of the border.

tural lintels, for domestic, commercial

The main reason why we are successfully

and industrial applications to engineers’

recruiting new members from that quarter

specifications.

is that southern Africa looks to South

Bassbeams operates a modern plant

Africa and the CMA as world-class experts

with computerised batching, hydraulic

in precast concrete. And in recognition of our expanding African footprint, we have redesigned our branding to include the flags of all member countries.

Colonial Stone products including Manor flagstone pavers around the pool, Fieldstone cladding on the back wall of the pavilion, and Ledgestone cladding on the pillars, were used to great effect at this private residence.

Delta Bloc

“We are the voice of the precast

Based in Gauteng, associate member,

concrete industry in southern Africa

Delta Bloc South Africa markets precast

and the CMA logo is a widely respected

concrete vehicle restraint systems (crash

brand and a recognised badge of quality.

barriers) for median barrier and verge

Many construction professionals in the

applications. The barriers can also be

private and government sectors insist

used as an alternative to standard bridge

on CM A member s’ pr oduc ts and we

parapet designs.

engage with national and local government

A subsidiary of Delta Bloc International

bodies and lobby for the greater use of

in Austria, the brand first entered the

precast concrete.

The installation of a Bassbeam Type 200 T-Beam at the Splish Splash Car Wash, in Cato Manor, Durban.

local market in 2007 when 50km o f

PRECAST VOLUME 7 • ISSUE 2 • 2013


16

ARTICLE

temporary barriers were supplied for use

It also produces the FastBloc “T”

on the Gauteng Freeway Improvement

beam and block system, which is used in

Project during the construction phase.

outlying areas where crainage is scarce

Delta Bloc South Africa uses various

and transport expensive.

concrete, textile and fibre cement,and in fibreglass and polymer concrete. I t s p r o du c t r ang e in clu d e s p l an t containers, water features, columns and

sub-contractors to manufacture the

FastDeck has a registered office in

veneer mouldings, paving and cladding, and

restraint barriers in compliance with the

South Africa, FastDeck Floors cc, based

is suitable for residential, commercial,

SABS standard SAnS 51317 as well as

in Rustenburg. It can handle projects

municipal and industrial applications.

for the production of precast concrete

undertaken in the Republic supplying slabs

Style Decor custom-makes architectural

noise barriers. All barriers are crash-

manufactured in the Gaborone plant.

decorative elements and mouldings to

tested to ensure that reliable levels of

View on www.fastdeck.com or contact

client requirements, supplying outlets

breakthrough protection are achieved.

Peter kernick on 00267 397 1974 or via

throughout South Africa. It also exports

View on www.deltablocsa.co.za or contact

peterk@fastdeck.co.bw .

to Botswana, England, Ghana, namibia,

Garth Strong on 082 492 4678 or via garth@deltablocsa.co.za.

Seychelles and the UAE. Namib Roof Tile Company

V ie w on w w w.s t y le de c or.c o .z a or

namib Roof Tile Company began manufac-

contact Alf Morgan on 087 941 3889 or

turing concrete roof tiles in 2007. owned

via management@styledecor.co.za.

by Mr. Horst Fritze and based in Swakopmund, it has been trading as Swakop Tiles cc but is now being branded nationally as the namib Roof Tile Company. Capable of producing 8 000 concrete roof tiles per shift, the company produces high-quality, aesthetically pleasing and durable roof tiles. Tiles comprise a local content of 97% and elaborate testing is performed on each production batch to ensure a high-quality A Delta Bloc precast concrete barrier on a stretch of road in Magoebaskloof, Limpopo.

end-product. Periodic tests are also run by the SABS for compliance to SAnS 542:2012. Results to date exceed the

FastDeck

A house built using Style Decor’s precast concrete water feature products and concrete columns.

SAnS standard by a factor of two.

Based in Gaborone, FastDeck is the only

View on www.swakopies.co.com or con-

prestressed hollow-core concrete slab

tact on 061 222965 or via nrtc@iway.na.

Tjeka Training Matters Associate member, Tjeka Training Matters

manufacturer in Botswana. It produces

is a pr i v a tel y-ow ned company w hich

slabs in excess of 40 000m² annually to

undertakes skills and entrepreneurial

very high specifications and standards

development in the construction and civil

using high-tech concrete forming machines

engineering industries.

made in Germany.

The company was formed by a group of training facilitators in 2000. Previously disadvantaged individuals have a 72% shareholding in the company and 66% of

A roof constructed with concrete roof tiles supplied by Namib Roof Tile Company.

Style Decor Located west of Pretoria, Style Decor (est. 1965) designs and manufactures FastDeck prestressed hollow-core concrete flooring slabs being installed at the Wharic Hotel project on the Phakalani Golf Estate in Gaborone, Botswana.

PRECAST VOLUME 7 • ISSUE 2 • 2013

o r n a m e n t a l p r o d u c t s f o r g a r d e n s, interior s and building applications in

A Department of Foreign Affairs project in Pretoria, where training in plastering, brick and block laying was given by Tjeka Training Matters.


ARTICLE

17

board of director representation has a

Growth of precast concrete industry

BBBEE status as a level 2 contributor.

Armstrong says the CMA has done much

The company operates nationally from

to grow the precast concrete industry

offices in Gauteng, the Western Cape,

since its inception 41 years ago.

the Vaal Triangle, the Eastern Cape and

“We know that future opportunities

kwaZulu-natal.

for growth in southern Africa are huge.

View on www.tjeka.co.za or contact

We intend unlocking this potential over

Frans Toua on 011 665 2777 or via frans@

the coming years and believe that other

tjeka.co.za.

manufacturers will join us in this process.”

Vaka Concrete

8 0 5 - 674 2 o r dir e c t o r @ cm a .o r g .z a .

Founded in 2012 in Harare, Zimbabwe,

Alternatively view www.cma.org.za.

Contact Wally Armstrong on (011) P

Vaka Concrete manufactures concrete bricks and pavers in a variety of colours.

The Vaka concrete batching plant in Zimbabwe.

requirements.

raw materials, ensures the quick and

For f ur ther inf ormation contact

homogenous mix essential to consistent

Tawanda Muindisi on 00263 4 746 955

product quality. Independent testing by

or via tmuindisi@vakaafirca.co.zw.

n

Standards Association’s minimum quality

mayer, which together with high-quality

iatio

Vaka’s product range far exceeds the

technology from CMA member, Berken-

ncrete

Laboratories, have demonstrated that

Vaka’s plant uses the latest mixing

co

northern Testing Laboratories and Ascon

this year.

s

soc

the Standards Association of Zimbabwe,

its product range during the course of

a

facturer

as

and perimeter walling will be added to

m

Concrete blocks for low-cost housing

nu

Q

ua

lity

cast in conc

re

te

DRY BULK SEPARATOR (YFEL)

www.remacon.co.za T: 011 393 5504 | F: 011 393 5502


18

ARTICLE

quickly offset any higher capital spend,” says Voogt. This is by no means pie-in-the-sky. The Royal Bafokeng Administration (RBA) is

cONcrete BLOcK paVING Ð An IDeAL ALteRnAtIVe to AsPHALt RoADs

saving some R13 million (R42 000 per kilometre) annually on the maintenance - or the lack thereof - on CBP roads in nor thwest Province. T he programme began in 1996 when the RBA chose CBP to surface some of the roads in the villages on the outskirts of Rustenburg. And concrete block paving is spearheading a poverty alleviation and road r e su r f a c i n g p r oj e c t i n G e o r g e . T h e lo c al municip ali t y is r e sur f acing i t s deteriorating suburban asphalt roads as well as some gravel roads with CBP in all residential areas. This ongoing project began in 2001 and since then some 53km of roads at an average width of five metres have been

A CBP street in Rosemoor, George.

resurfaced with CBP. In addition, 49km o f p a v em e n t s 1.5m w i d e h a v e b e e n sur f aced with CBP. T he pr oject also

Concrete Block Paving (CBP) has been used to pave public roads in South Africa for close on 50 years. The first public roads to be surfaced with CBP were in Chatsworth, Durban, 49 years ago. These roads have been essentially maintenance-free and have provided double the service-life of a good asphalt surface. Moreover, the roads are still in very good condition and may well last another 50 years.

includes a small percentage of roads and

T her e ar e countless other examples

local governments are under severe budget

was only used where the water table was

in which CBP has been used for public

constraints and in many cases are unable

deemed low enough and the sub-grade

roads and this is why the CMA’s technical

to maintain their existing road networks,

sufficiently stable by the main contractors,

director, Taco Voogt, believes that CBP can

which are largely paved with asphalt.

Power Construction. The contract included

help offset the current shortfall in asphalt

We also know that CBP is essentially

a 10-year latent defect clause and this was

supplies and why CBP will continue to grow

maintenance-free provided it is laid in

the main reason why CBP was deployed

its market share of public road paving.

compliance with best practice standards.

in the sections where the sub-grade

“There is more than sufficient cement,

What’s more, the initial capital outlay on

was unstable. The company believed that

sand and aggregate, the basic ingredients

CBP roads is only marginally greater than

asphalt roads would have begun to crack

used to manufacture concrete blocks,

the asphalt equivalent. Therefore it makes

after only five years.

to supply South Africa’s needs. In fact

sense for all new urban road projects

There are countless other examples

the industry carries considerable spare

to be surfaced with CBP. The saving on

of local governments opting for CBP as

capacity and production could easily be

maintenance would be huge and would very

the most cost-effective and sustainable

This CBP road surface in Chatsworth still looks good after 49 years.

One of several CBP roads in Jordaan Park, an upmarket suburb in Heidelberg (Lesedi).

parking areas in the CBD as well as some servitudes and footpaths. And in a new housing project in klapmuts, Western Cape, half the roads and accesscourse surfaces have been paved with CBP. A high water table and unstable subgrade material (earth) meant that asphalt

stepped up to meet increased demand. “A s h a s b e e n d e m o n s t r a t e d i n Chatsworth and other townships, sustainability is one of the major considerations in choosing CBP. Cost, closely allied to sustainability, is another, and so are poverty alleviation, safety and aesthetics. “Sustainability is key to CBP’s growing acceptance as an alternati ve pav ing medium to asphalt. As we well know, most

PRECAST VOLUME 7 • ISSUE 2 • 2013


ARTICLE

19

solution, and not only in South Africa. Ripon, a city east of San Francisco in California, USA, has standardised on CBP for all new roads. This decision was prompted by the destruction of a new asphalt road by heavy-truck traffic a few months after its completion. In addition, Ripon’s cost of maintaining its existing asphalt road structure was $4 240 000,00 a year, whereas the revenue available to meet that requirement was only $710 000,00. Building better roads that required less maintenance was deemed to be part of the solution and the council opted for CBP as the standard road material. Another deciding factor was that in addition to the structural stability that pavers provided they offered a significant and pleasing visual contribution.

A close-up of an open-channel drain paved with concrete block paving in Lefaragatlhe, one of the 28 Royal Bafokeng villages in Northwest Province, where CBP has been used extensively.

“We would like to see major intersections

ownership among residents in surrounding properties.

L ay ing r oads with concr ete block

paved with CBP. The acceleration and

paving is labour intensive and offers the

breaking of heavy trucks destroys tarred

T he CM A has numer ous technical

unskilled and unemployed an opportunity

intersections fairly quickly. Intersections

manuals and audio visual aids on CBP which

of acquiring a marketable skill and earning

paved with CBP last a lot longer. Then

are available at a nominal cost.

income. over the years thousands have

there is the noise factor. As a vehicle

“For instance, we have printed a general

benefitted from CBP projects. The income

moves from a tarred to a CBP surface the

booklet on the advantages of CBP and last

earned has a multiplier effect, stimulating

change in roads noise can alert a driver

year we published our ‘Step-by-step guide

economic activity in other sectors of

that a crossing is imminent.

to Perfect Paving’ aimed mainly at the

local communities. Moreover, it imbues

unemployed township dweller, who, by using

residents with homes on CBP roads with

the manual, can develop a useful income-

a new-found pride in their communities and

producing skill. “While its principal objective is to gener-

this is reflected in cleaner streets and

ate employment opportunities, the manual

better-maintained houses.

is sufficiently informative and technical to

Voog t said tha t CBP con tr ibu tes

be used as refresher material for contrac-

significantly to road safety. “First, the chance of aquaplaning on

tors, both large and small. It is also being

wet surfaces is greatly reduced with

offered to training and technical institutions

CBP roads. The two to three millimetre

as course material. The DIY user too will find

water sheet often found on asphalt roads

the manual of considerable benefit.

during heavy downpours is virtually non-

“Then we have published a booklet

existent, especially when the pavers are

which compares the cost of CBP with

bevelled. one may find an isolated water channel crossing a CBP road but not water

Taco Voogt, CMA technical director.

premix asphalt paving, and we offer several specialist manuals. These include: CBP

sheeting over an extended area. Permeable

“Another advantage of CBP is that the

Drainage; Specification and Installation;

paving installations, which are specifically

individual paving blocks can be lifted, for

and Site Management and Laying. We also

designed to soak up stormwater, are even

instance for the laying of water pipes and

offer paving-design software, Lockpave,

more effective at dispersing surface water

underground cabling, and then replaced

for conventional paving and PermPave for

and can be installed on sections of road

with no visible sign of disturbance, unlike

permeable installations.

where water channels are likely to form.

tar surfaces which must be broken and

“CBP also offers better braking, thanks

then patched.”

“Irrespective of the supply situation for asphalt we believe that all new urban and

to its rough texture and broken surface. In

When using CBP for road surfaces, it

rural roads should be surfaced with CBP.

addition, it provides better road marking

is also very easy to construct pavements

It makes socio-economic and environmental

with coloured and luminous concrete pavers.

and cycle paths adjacent to the roads at

sense. All it requires is a mind-shift on

They offer constant and maintenance-free

very little additional capital outlay. Proper

the part of the local authorities to adopt

signage, unlike painted surfaces which

pavements and kerbing have an uplifting

a process which has already been widely

require regular maintenance.

effect on communities, enhancing pride of

used,” concludes Voogt.

P

PRECAST VOLUME 7 • ISSUE 2 • 2013


20

APPLICATIonS

eNHaNceD concRete WoRKABILIty The South African construction industry

dosage of product and concrete materials

range of applications with high or low water/

is demanding greater workability time for

used, while still maintaining good early

cement ratios and/or high or low ambient

fresh concrete. one solution, introduced

strengths. It uses a polycarbox ylate

temperatures. Consistency and duration

by Sika South Africa, is Sika ViscoFlow.

ether-based superplasticiser (PCE) and

of workability of concrete mixtures are

It extends the workability of concrete

allows time to transport and place the

positively affected along the entire dosing

up to four to six hours, depending on the

concrete properly. This is important for

spectrum. This holds true for all Portland

urban construction sites prone to traffic

cement types.

congestion, or for remote areas. Sika ViscoFlow offers: • Slump retention without additional

are used and are always based on proven

r e t ar da tion and sub se quen t f as t

Sika ViscoCrete Technology. Consistent

strength development

and rigorous development has generated

• Constant slump flow and consistency for up to four to six hours • Extended workability for high performance concrete with low water/cement ratios and high durability properties • G o o d p e r f o r m a n c e u n d e r v a r y in g env ir onmental conditions such as hot climates. Concrete improved with Sika ViscoFlow is poured on site.

Sika ViscoFlow superplasticisers are adapted to local conditions wherever they

Sika ViscoFlow is suitable for a wide

extremely robust PCEs for daily use, which are provided globally under the Sika ViscoFlow brand name. Sika ViscoFlow represents a valuable addition to Sika’s polymer toolbox, broadening the range of applications and fulfilling challenging customer requirements. For more information on Sika products and systems, visit zaf.sika.com


APPLICATIonS

21

reMacON LaUNcHes FreestaNDING BuLK-stoRAGe systeM ReMaCon has developed a free-standing precast wall element, the YFELTM, which provides a flexible dry-bulk material storage system, both for internal and external applications. The concept was inspired by the shape of the Eiffel Tower, hence its name YFELTM . Individual units can be placed into position with forklifts, or other equipment using forked attachments. Varying between 1.2m to 4m high, the YFELTM can be bolted onto concrete floors or onto purpose-cast foundations with chemical anchoring for added stability. ReMaCon has also extended the YFELTM range to include an anti-climb feature for high security walling purposes. This

ReMaCon’s YFELTM, which provides a flexible dry-bulk material storage system.

walls fitted with the feature. TM

Production of the YFEL

C

M commenced in

consists of a cur ved top end, which

2012 and the first order was delivered to a Y

prevents potential intruders from scaling

fertilizer blending facility in February 2013. CM

MY

BOsUN INcreases KerB MAnuFActuRInG cAPAcIty

CY

CMY

K

Bosun’s production of SABS-approved

one of only a few South African producers

dry-cast concrete kerbs was significantly

utilising the technology. By contrast, in

increased in July when a new plant was

Europe it is used almost exclusively by kerb

commissioned.

manufacturers.

T h e d e c i si o n w a s m a d e f o ll o w in g

The innovative Castle Bottom kerb (pat-

increased demand for Bosun’s dry-cast

ent pending) will also be produced in the new

kerbs and concrete pavers throughout

production facility. Three shapes of kerbs

South Africa and the new plant will increase

are currently available in Castle Bottoms

Bosun’s capacity for kerb production by

and shipped to all parts of the country.

120,000 units (meters) per month.

Generic flat-bottom kerbs are, however,

Bosun says that dry-casting of kerbs

still produced for certain customers.

is much more reliable and efficient than

The new factory will relieve Bosun’s ex-

traditional wet-casting and the company is

isting plants from having to manufacture kerbs which frees them to increase production of paving and retaining wall blocks. As with all Bosun’s manufacturing equipment, the new kerb plant was imported from Germany and German exper tise w as f lo w n in f or the c ommissioning phase. A l though B osun’s st a f f ha v e been manufacturing dry-cast kerbs for several years, the company believes in optimising the transfer of knowledge from

Bosun’s current kerb production facility.

its associates abroad.

PRECAST VOLUME 7 • ISSUE 2 • 2013


APPLICATIonS

23

precast cONcrete pOLes RePLAce VAnDALIseD steeL PoLes The Ekurhuleni Metropolitan Municipality

The design and project management

has opted to replace vandal-prone steel

work for the project is being handled

street-lighting poles with prestressed

by Secret Steps Trading and the actual

I-shaped concrete poles in several of its

installation work is being done by several

municipal districts. one of the country’s

sub-contractors, each employing between

leading precast concrete manufacturers,

10 and 20 people.

C M A m emb er, Av eng Manu f a c tur ing

The concrete poles are being planted

Infraset, won the tender to supply 800

in manually-dug holes approximately 1.2m

concrete poles for the first phase of the

deep in strict compliance with Health and

project, which is based in Springs.

Safety regulations.

According to Richard Baloyi, a support

Makhura says I-shape poles are ideal

ser v ices engineer a t the E kur huleni

for this type of installation and they make

Metropolitan Municipality, steel poles are

the mounting of street lighting both easy

an easy target for vandals.

and secure.

“They are being cut down on our more

“The high strength-to-weight ratio of

remote and sparsely populated roads,

the I-shaped poles puts them in a class

especially on the Springs/Brakpan, Springs/

of their own. Moreover, the poles for

nigel and Springs/Duduza routes, and

the Springs project were manufactured

this is where Phase 1 of the replacement

with ear thing bar s to pr otect them

project has unfolded.”

against lightning. Their excellent weight-to-

Actual pole replacement began in June 2012 and Phase 1 will be completed in June

strength ratios and their reduced weight made them easy to offload and handle.

2013. Steel poles which have not been

“The poles for this project were cast at

damaged are being replanted in the suburbs

our Brakpan factory in high-strength, high-

where the incidence of pole vandalism

density concrete with a smooth finish. The

hardly exists.

resilience of prestressed concrete poles

Aveng Manufacturing Infraset product

enables them to recover from the effects

manager, Mothemane Makhura, says two

of a greater degree of overload than any

lengths of concrete poles, 10 and 11

other type of structural material.”

metres, both rated at 8kn, were supplied for the project. Baloyi comments that concrete poles were specified, because unlike steel poles, which are relatively easy to hack down, they are virtually vandal-free. “Moreover, concrete poles are rust-free and have much longer life spans.” Commenting further Baloyi says that it’s not the poles themselves that the vandals are after but the copper content in the light fittings, which is sold for scrap. “We are also replacing the underground copper cabling with overhead aluminium bundling which means that our street lighting will be far less vulnerable to theft. The Ekurhuleni Metropolitan Municipality regards street lighting as indispensible in the fight against crime and this is why we are treating this project as a matter of urgency.”

Wit Road, Springs, where prestressed concrete poles have replaced vandal-prone steel poles.

PRECAST VOLUME 7 • ISSUE 2 • 2013


24

APPLICATIonS

LONG-staNDING retaINING WaLLs eXtenDeD WItH teRRAFoRce BLocKs A successful product is one that gets

its extension was completed in December

site also included several smaller walls,

used more than once, Two projects, which

last year by Decorton using a further

such as a rock face weir and various low

used the same Terraforce retaining blocks

13 000 Terraforce L12 Rock Face blocks.

toe walls. In total, Dassenberg Retaining

to extend long-standing retaining walls,

At a maximum height of 1.8m on each

installed 24 000 Terraforce Standard

terrace, the original wall was designed with

(round face) blocks, which were planted

three curving terraces of varying width

almost exclusively with hardy indigenous

Oasis Retirement Resort, Century City,

on a berm 500m long. Each terrace had a

species. The installation is now 10 years

Cape Town

concrete foundation and subsoil drainage

old and has proven to be very stable and

Approved by property developer, Harries

was installed behind each bottom row of

easy to maintain.

Projects and built by Decorton Retaining

blocks. The earth backfill on every third

Constant erosion problems, a partial

Systems using 8 000 Terraforce L12

row of blocks was reinforced with Polytex

collapse of new building platforms and

Rock Face blocks in 2006, this undulating

115 geofabric.

unsightly cut slopes led natalie du Preez,

illustrate the point.

retaining wall shields the oasis Retirement

Seven years on, the original wall is

property asset manager at Acucap, to

Resort from excessive noise and prying

completely covered by mostly water-wise,

initiate another retaining wall project on

eyes. Also approved by Harries Projects,

indigenous plants which assist in the

the same site using Terraforce L11 Rock

effective prevention of wind erosion on

Face blocks. Completed last year, Acucap

the gently sloping embankments that face

approved the wall’s design based on the

the buildings.

successful application of the product during earlier phases of the project.

Tygerberg Office Park, Tygerberg

The new section of the Terraforce noise barrier wall under construction at the Oasis Retirement Resort in Cape Town.

Consulting engineer, Erik Raymond,

In 2003 site excavations of a steep building

obser ved that steep sections of the

site lef t a five metre high, 95m long

embankments had to be protected with

embankment, with a 30° surcharge slope

flexible earth retaining block walls to

above it. Property developers, Atterbury

reduce the erosion of the excavated face,

Cape, approved the construction of a

to prevent excessive ingress of water and

composite Terraforce wall which included

to make the area visually appealing.

a four percent cement-stabilized and

The sheer height and steepness of

geof abric-r einf or ced back f ill, cut-of f

some of the walls left no space for geogrid

drainage and a subsoil drainage system.

reinforced backfill, and a double layer of

other retaining walls on site included

blocks with reinforced concrete ( Y12

two six metre high structures which

re-bar) had to be used instead of infill on

stabilised a 12m high fill platform. The

some sections.

BOsUN INtrODUces neW PAVInG FInIsHes Bosun has introduced a new range of

attractive textures on various pavers and

is the process of diamond cutting the

beneficiated paving units which is being

to facilitate the construction of parking

product to exact thicknesses. This ensures

produced in a new custom-built factory using German hydraulic press technology.

areas, roads, boulevards and paths.

total dimensional accuracy. It also makes

Certain kerb shapes can also be

the product installation much quicker and

produced in exposed finishes

easier and yields an aesthetically pleasing

Commissioned in July,

to cater for aesthetically

the new plant is produc-

pleasing road edging to

“As we say on our logo, our customers

ing paving finishes such

ei ther ma tch or o f f se t

should expect the best f r om Bosun.

driveways, paths or com-

We simply need to keep our heads down

as exposed aggr egate, ground concrete and shotblast concrete.

mercial road surfaces. Bosun’s range of large pavers,

According to David Wertheim

some of which measure up to 27 times

Aymes, CEo of the Bosun Group, these

the size of standard paving bricks, are now

f inishes are being of f ered to create

available in a calibrated option. Calibrating

PRECAST VOLUME 7 • ISSUE 2 • 2013

flat surface.

and produce the best, as that is our promise and our customers’ expectation,” Wertheim Aymes concluded. Bosun’s medium Urban Paver in a black washed finish.


APPLICATIonS

25

pMsa INtrODUces MoBILe BRIcK MAKInG MAcHInes to AFRIcA In or der t o o v er c ome the logis tic al

attachments for the manufacture of

challenges associated with rough terrain

concrete paving blocks.”

and remote locations in Africa, mobile brick

In addition to the VB1X, Booysen adds

making machines have been introduced

that PMSA also supplies the RE600, VB1

by Pan Mixers South Africa (PMSA ),

and UnI plant block making machines in

which claims to be the largest supplier of

mobile models. “Development in Africa

concrete, brick, block and paving making

is taking place at a rapid rate, and as

machinery and technology in Africa.

industrialisation continues, I believe that

PMSA marketing and sales manager,

mining, housing and government projects

Quintin Booysen, points out that the

in particular will benefit from the PMSA

company delivered its first mobile VB1X

mobile plant range.”

concrete block making machine in May this

Booysen stresses that the company

year to a construction client based in the

is able to deliver the highest standards

Democratic Republic of Congo.

of customer service and quick turnaround

“As Africa develops and infrastructure

time on spares, due to the fact that it has

is r olled out, the demand f or mobile

a comprehensive stockholding onsiteC to

machines in various forms is increasing,

eliminate the associated risks of downtime M

and PMSA has identified this trend early.

for its clients.

The VB1X is capable of producing up to

Y

“PMSA prides itself on assisting its CM

60 000 stock bricks per day, and the

customers by consistently delivering on

mobile version can simply be moved from

its promises. We always endeavourMY to

site to site, thereby enabling customers

source non-stock parts in the shortest CY

to produce high volumes of bricks with-

time possible,” he says.

CMY

out constantly investing additional capital,

What’s mor e, Booysen points out

even in the most r emote locations,”

that PMSA produces all the principle

he explains.

components and assemblies in-house.

K

The mobile VB1X block making machine

“PMSA reduces its reliance on outside

features remote electro-hydraulic

suppliers, as their level of service does

controls, in addition to a high-energy

not always meet the company’s high

double-shaf t directional vibrator with

expectations of quality, deli ver y and

maintenance-f r ee dynamic braking.

turnaround time. By manufacturing our own

Booysen notes that the electro-hydraulic

components, in-house specialists are able

operation of the tamper, mould box and

to source and address any problems swiftly

feed drawer ensures automatic filling of

and effectively,” he concludes.

the mould from an overhead silo. “What’s more, an automatic hydraulic pallet f eeder f eeds pallets f r om the magazine to the moulding head and ejects them onto the take-of f conveyor,” he continues. Booysen notes that the mobile VB1X block making machine is purpose built for the challenging African terrain and weather conditions. “PMSA is the leading and largest supplier of brick and block making machinery in Africa, and all our equipment is capable of producing high qualit y end pr oduc ts that mee t the SAnS standards. Furthermore, PMSA also offers machinery with topping feed

A PMSA mobile brick making machine.

PRECAST VOLUME 7 • ISSUE 2 • 2013


26

APPLICATIonS

tecHNIcrete paVers UseD at MAHWeLeRenG sHoPPInG centRe

and factory roads. “It was the quality,

The 800 motor vehicles that are expected

2 700 280x180x140 semi-mountables to

vehicle loading at Mahwelereng, which

to visit the new Mahwelereng Shopping Mall

prevent vehicles from driving over kerbs and

will only increase as the centre gains

in the Limpopo Province daily, will be parking

into non-designated vehicle areas; ninety

popularity” concluded oberholtzer.

safely on 8,000 square meters of Techni-

300x200x100 mountable kerbs where

crete Double Zig-Zag interlocking pavers.

pedestrian and commercial walkways met

Technicrete pavers, which offer SABS

with the parking surfaces; 12,000m2 of

compliance and a high MPa strength will

grey Double Zig-Zag 60mm interlocking

ensure that that the quality of the roads,

pavers as well as 2,000 m2 of 80mm grey

kerbs and parking pavers provide a safe,

Double Zig Zag for the parking area. The key

smooth and long-life option.

to the success of the final appearance of

“The development offered us a more sta-

the parking facility lay in the skilled packing

ble soil environment than we had expected”

of the pavers. All pavers were fully aligned

said sub-contractor Hanno oberholtzer.

and level, resulting in an even finish. The

“Although there were a few sections where slopes were not ideal and water

supplied by Technicrete that made its interlocking pavers the best choice to absorb and withstand the anticipated

final product (as pictured) provides a firm and well-interlinked surface.

flows to stormwater channels required cut-

The 60mm and 80 mm Double Zig Zag

and-fill platforms, it was a very successful

interlocking pavers are particularly well

project. Moreover, Technicrete’s close

suited to areas that have high vehicle

proximity made it a natural supplier”.

traffic volumes such as retail outlets,

Technicrete supplied all the kerbs:

appearance and durability of the pavers

petrol station forecourts and industrial

Part of the parking area at the Mahwelereng Shopping Centre, Limpopo Province, where the Technicrete grey Double Zig Zag pavers were installed.


28

CMA MEMBERS

Producer members COMPANy NAME

TELEPHONE

PROVINCE

PILLAR

A Fick Sementwerke

(022) 913 1921

WC

PB

Aveng Manufacturing Infraset

(011) 876 5100

JHB

PB/PI

Bass Beams

(031) 784 1938

kZn

Bay Brick

(035) 792 5218

Beta Tiles

COMPANy NAME

TELEPHONE

PROVINCE

PILLAR

Mobicast

(044) 874 2268

WC

PB/PI

Monier Roofing South Africa

(016) 430 8000

JHB

PB

PB

MVA Bricks

(012) 386 0050

JHB

PI

kZn

PB

Swakop Tiles cc

0061 222 965

nAM

PB

002634 2925303

ZIM

PB

ReMacon

(011) 393 5502

JHB

PI

Boland Concrete

(021) 875 5365

WC

PB

Revelstone

(0861) 173 835

WC

PB

Bosun Brick Midrand

(011) 310 1176

JHB

PB

Reya Pele Bricks Ltd

(016) 363 0340

JHB

PB

Brickbuild t/a Panda

0026 244 2107/8

BoTS

PB/PI

Rocla

(011) 670 7600

JHB

PB/PI

Brickcast Industries cc

(031) 507 5525

kZn

PI

Salberg Concrete Products

(011) 357 7600

JHB

PB/PI

C.E.L. Paving Products

(021) 905 5998

WC

PI

Shukuma Flooring

(041) 372 1933

EC

PB

Cast Industries

(011) 316 2375

JHB

PB/PI

Southern Pipe Contractors

(011) 914 8500

JHB

PB/PI

Colonial Stone

(011) 794 9737

JHB

PB/PI

087 941 3889

JHB

PB/PI

Concrete Units

(021) 386 1923 (016) 362 2236

WC/JHB

PB/PI Technicrete

(011) 672 1425

JHB

PB/PI

Conframat

(0861) 33 5599

JHB

PB/PI

Topfloor

(021) 951 7700

WC

PB

Corobrik

(031) 560 3111

kZn

PI

00263 04 746955

ZIM

PB/PI

Deranco Precast Deranco Blocks Deranco Paving (Pty) Ltd

(041) 933 2755

EC

PB

(012) 541 2056/1808

JHB

PI

(011) 851 1098

JHB

PI

Eagle Roof Tiles (Pty) Ltd

(044) 874 0290

EC

PB

Echo Prestress (Pty) Ltd

(011) 589 8800/8899

JHB

PB

Fastdeck (Pty) Ltd

0026737 71321528

BoTS

PB

Inca Concrete Products

(021) 904 1620

WC

PB/PI

Inca Masonry (Garden Architecture)

(043) 745 1215

EC

PB/PI

082 850 3512

JHB

PI

kwena Concrete Products

00267 3922850

BoTS

PB/PI

Lategan Cement Works

(021) 873 1154

WC

Marley Roofing

(011) 316 2121

JHB

Style Decor Design & Manufacturers

Vaka Concrete (Pty) Ltd Vanstone Precast (Pty) Ltd West End Clay Bricks PI - Precast Infrastructure

keystone Walling

PB - Precast Building

coNTrAcTor members COMPANy NAME

TELEPHONE

PROVINCE

Decorton Retaining System

(021) 875 5155

WC

Friction Retaining Structures (Pty) Ltd

(011) 608 4321

JHB

PYW Paving

(031) 903 1736

kZn

PB

Roadstone Civil & Paving

(011) 683 7080

JHB

PB

SA Paving Gauteng

(011) 483 1350

JHB

Please fill out the form below and fax it to +27 11 783 2677 name: _______________________________________________________________

T AS PREC EC AST R P PRECAST VOLU

ME SIX

1

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VALUE

FOR

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1 • 2012

THE

VOLUME

FOUR ISSUE

1 • APRIL 2010

CMA

– QUA

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CAST

Postal address: ______________________________________________________ ______________________________________________________________________

IN CON

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NCE

PLIA

COM

ISSUE

EY MON

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THE CMA

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– QUALIT

CONCRETE

______________________________________________________________________ Telephone: (H) ________________________________________________________

ns ign illio des ng R-m ssi es cro sav ereng lock el riv fok niB -lev al Ba Mi low • Roy 20/40 ng in aili • The det

• Conc rete piping • Exten for mass sive ive infras retai reta • UK ning flood truct wall allevi ure proje proje ation ct ct schem s e

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on? destructi of our own the seeds gap housing • Sowing pace for sets the concrete • Leo Mews e and precast Conferenc • SA Housing

the cma – QUaLItY caSt IN cONcRete

Telephone: (W) _______________________________________________________ Mobile:_______________________________________________________________ Email: ________________________________________________________________


CMA MEMBERS

29

AssociATe members COMPANy NAME

TELEPHONE

PROVINCE

(012) 348 6668

JHB

+44 116 253 6161

Uk

ILIFA Africa Engineers (Pty) Ltd

(016) 981 0591

JHB

JC Paving Consulting

(011) 431 0727

JHB

Pipes cc

(012) 644 0043

JHB

Sekhukhune & Associates

(012) 993 4776

JHB

SnA Civil & Structural Eng

(012) 842 0000

JHB

Terraforce (Pty) Ltd

(021) 465 1907

WC

Tjeka Training Matters

(011) 665 2777

JHB

Young & Satharia Consulting Civil Engineers

(031) 207 7252

kZn

ARQ Consulting Engineers British Precast Concrete Federation

NoN-Producer members COMPANy NAME

TELEPHONE

PROVINCE

Able Equipment

(044) 874 1876

EC

Ash Resources (Pty) Ltd

(011) 886 6200

JHB

Birkenmayer H (Pty) Ltd

(011) 970 3880

JHB

BASF Construction Chemicals South Africa (Pty) Ltd

(011) 203 2400

JHB

Chryso Southern Africa (Pty) Ltd

(011) 395 9700

JHB

Delta Bloc South Africa (Pty) Ltd

(011) 024 4604

JHB

Dick king Lab Supplies

(011) 499 9400

JHB

kavango Block & Brick

+264 61 213 632

nAM

kaytech

(031) 717 2300

kZn

kerneos Aluminate

(011) 444 3090

JHB

kobra Moulds B.V.

003111 356 2460

nETH

Manitou SA (Pty) Ltd

(011) 975 7770

JHB

Mapei SA (Pty) Ltd

(011) 552 8476

JHB

Pan Mixers SA (Pty) Ltd

(011) 397 3754

JHB

Sika South Africa (Pty) Ltd

(031) 792 6500

kZn

Soilab (Pty) Ltd

(021) 988 7410

WC

Smartstone (Pty) Ltd

(011) 310 1161

JHB

0048 480 369 0811

PoL

(021) 535 4455

WC

Techmatic S.A. Technical Finishes

SAFETY IS OUR GOAL.

WHAT IS YOURS? It is our primary belief that Occupational Health and Safety at the workplace should be of utmost importance to any employer. In today’s increasingly competitive business climate, any factor that affects the bottom line can be the difference between a successful company and being out of business.

Our goal is to provide employers and employees with courses that will improve the productivity of their company and at the same time help them to comply with the Occupational Health and Safety Act, Act 85 of 1993.

WHAT WE OFFER: Health and Safety Training First Aid Training Fire Fighting Training If you require any more information about our services CONTACT ME. Please Note: In-house training can be arranged.

LINDA ROBERTS Branch Manager

cemeNT members COMPANy NAME

TELEPHONE

PPC Ltd

(011) 386 9000

JHB

Afrisam South Africa (Pty) Ltd

(011) 760 5520

JHB

www.risktrainingsolutions.com PRECAST VOLUME 7 • ISSUE 2 • 2013

T: 011 0569742 | C: 083 626 8814 | E: linda@risktrainingsolutions.co.za


m

a

nu

facturer

s

as n

co

iatio

ncrete

soc

Q

ua

lity

cast in conc

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te

16 Horn Street, Chloorkop, Kempton Park, Postnet Suite 8612, Private Bag X32, Kempton Park 1620 Tel +27 11 805 6742 • Fax +27 86 524 9216 e-mail: admin@cma.org.za

www.cma.org.za

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