Concrete Contractor April/May 2021

WORLD OF CONCRETE PREVIEW — Look for These Products at the Show!

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April/May 2021

THE LEADING TRADE MAGAZINE IN THE CONCRETE INDUSTRY

Polishable Overlay Sealants 42

MEET MIX DESIGN SPECS 8

THE HOME OF THE

FUTURE

The Benefits

3D TECH in Formwork of

26

How modern tech pushed this project ‘Above Grade’ 34

The Right

CRACK REPAIR

Option 18

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WHAT’S INSIDE

APRIL/MAY 2021 | Issue 3, Volume 21

COVER STORY 34 Squareness & Plumb: Thermal Mass Creates the Home of the Future This concrete residential home in Connecticut was recognized as CFA’s 2020 Above Grade Residence.

DEPARTMENTS 4 Editor’s Letter 16 New Products 30 Product Focus

Concrete Pumps & Placement Equipment

48 Advertiser Index 50 The Last Placement

Cover Photo Credit: The Concrete Foundations Association

FEATURES 6

World of Concrete Product Preview Find these products at the show.

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Are You Confident in Your Concrete Pavement Mix Design?

New developments in quality assurance can provide important information on the quality, durability, and compliance with mix design specs.

14 An Inside Look at the Updates in ACI 301-20 An explanation of the updates.

18 A Summary of Concrete Crack Repair Options How do we design and select the best repair option? It’s not as difficult as you may think.

26 Moving from 2D to 3D Formwork Planning Adopting BIM and collaboration platforms for managing project information.

46 Specification Guide: Screeds The technical informaiton you need for a smooth, flat surface.

32 A Mixer & Pump You Can Use Indoors Strong Manufacturing’s fully electric mobile mixer and pump machine is easy on the environment—and costs.

38 Challenge: Restore a Parking Garage, While Keeping it Open An eco-friendly solution for the removal of 200,000 sq. ft. of material.

42 Q&A: 6 Questions on Sealers & Polishable Overlays What the finished floor will look like tends to be important to the floor owner. Knowing the floor and your sealant will make all the difference.

ARE YOU ONE OF THE BEST CONTRACTORS TO WORK FOR? Best Contractors to Work for in Construction is a survey and awards program dedicated to identifying and recognizing the best employers and providing organizations with valuable employee feedback.

Enter online.

bestcontractorstoworkfor.com www.ForConstructionPros.com/Concrete

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EDITOR’S LETTER

Three Things to Expect at WOC 2021

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Published by AC Business Media

201 N. Main Street, 5th Fl., Fort Atkinson, WI 53538 (800) 538-5544 • www.ACBusinessMedia.com

s the first large-scale tradeshow the Nevada Department of Business and Industry approved to return to exhibit halls this June, World of Concrete 2021 will no doubt be an event for the history books. So far, the list online includes 551 exhibitors—everything from batch plant manufacturers JONATHAN KOZLOWSKI, to handheld tools, from surface prep equipment to pump EDITOR trucks are all planned to be part of the show.

JKOZLOWSKI@ ACBUSINESSMEDIA.COM Looking forward, here a few things we anticipate seeing: ➊ Safety. Informa AllSecure has set out standards to keep attendees safe. The World of Concrete website notes that over 88 hand sanitation units will be featured throughout the floor and that every attendee will receive a non-contact temperature check before entering the exhibit hall. Contact-less badge pickup will be the name of the game as they've announced that there will be no on-site registration—a hands-free scanning station should make this process quick and easy. ➋ A Mixed Bag. COVID has changed a lot, but it hasn't redefined a tradeshow.

Expect to see the latest power tools and solutions designed to help concrete contractors be more efficient and cost-effective. ➌ Information. Where once it would take someone days to walk the full floor, a smaller show might be a blessing in disguise. I've been attending tradeshows for 14 years now, and oddly enough it was the smaller events that allowed time to visit more booths and check out more equipment. Visit the exhibitors you want, get that demo, ask your questions, and bring home the details you need.

As always, stay safe out there.

ARE YOU ONE OF THE BEST CONSTRUCTION EMPLOYERS? Are you a great boss? Do you know one? Great employers are those who walk the talk. When they say they care, they show they do. When there is a problem on the jobsite, they don’t point fingers, they present solutions. Join us in celebrating these awesome employers with the inaugural Best Contractors to Work for in Construction award. Winners will receive global acclaim in Equipment Today, Asphalt Contractor, Concrete Contractor, Pavement Maintenance & Reconstruction, and on ForConstructionPros.com. Winning companies will be invited to attend an exclusive event in Las Vegas. There is no cost to enter.

Register at bestcontractorstoworkfor.com.

Entry forms and surveys are handled by independent research firm Best Companies Group. Businesses must have at least 15 full-time or part-time employees working in the U.S. to enter. Primary business activity must be either general building construction, earthmoving, paving, concrete, or specialty and trades such as underground, utility, electrical, HVAC, demolition, and others.

Facebook.com/ ConcreteContractor

Advisory Board

James Baty II Concrete Foundations Association Mt. Vernon, Iowa

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Editor Contributing Writers Senior Production Manager Art Director Audience Development Manager

Jonathan Kozlowski jkozlowski@ACBusinessMedia.com Kim Basham, Jim Baty, Brad Humphrey, Sean O’Keefe, Chad White Cindy Rusch April Van Etten Angela Franks

ADVERTISING SALES (800) 538-5544

Jon Sison Eric Servais Nikki Lawson Sean Dunphy Tadashi Soma National Automotive Sales

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Editor Managing Editor CHANGE OF ADDRESS & SUBSCRIPTIONS

PO Box 3605, Northbrook, IL 60065-3605, Phone: (877) 201-3915 Fax: (847) 291-4816 • circ.ConcreteContractor@omeda.com REPRINTS Sean Dunphy, (800) 538-5544 , sdunphy@ACBusinessMedia.com LIST RENTAL Bart Piccirillo, Sr. Account Manager, Data Axle, Phone: (518) 339-4511 Email: bart.piccirillo@infogroup.com AC BUSINESS MEDIA

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Published and copyrighted 2021 by AC Business Media.

All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording or any information storage or retrieval system, without written permission from the publisher.

CONCRETE CONTRACTOR (USPS 021-799, ISSN 1935-1887 (print); ISSN 2471-2302 (online) is published 7 times a year: January, February/March, April/May, June/July, August/September, October/November and December by AC Business Media, 201 N. Main Street, 5th Fl., Fort Atkinson, WI 53538. Printed in the U.S.A. Periodicals postage paid at Fort Atkinson, WI, and additional entry offices. POSTMASTER: Send address changes to Concrete Contractor, PO Box 3605 Northbrook, IL 60065-3605 APRIL/MAY 2021, Issue 3, Volume 21 One year subscription to non-qualified individuals: U.S. 1 year: $35, 2 years: $70. Canada & Mexico 1 year: $60, 2 years: $105. All other countries 1 year: $85, 2 years: $160 (payable in U.S. funds drawn on U.S. banks). Single copies available (prepaid only) $10.00 each (U.S., Canada & Mexico), $15.00 each (International).

Canada Post PM40612608. Return Undeliverable Canadian Addresses to: Concrete Contractor, PO Box 25542, London, ON N6C 6B2.

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APRIL/MAY 2021

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Printed in the U.S.A. Concrete Contractor is the Official Media Sponsor of the CFA Foundation Company Certification Program

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U M A

FIND THESE PRODUCTS AT THE SHOW The Lavina Elite V32 Dust Extractor

Superabrasive’s Lavina Elite V32 Dust Extractor takes dust collection to a new level of performance and productivity.

Lavina Elite dust extractors features a four-stage dust collection for a dramatic increase in cleaning efficiency.

Additional features include: • An integrated emergency lamp reminds the operator to clean the filter.

• Option to upgrade to automatic cleaning • Lighter and more compact body design.

• Offered in propane and electric models.

Aquajet Systems’ Ergo System

Ligchine’s SCREEDSAVER ELITE

Aquajet’s Ergo System robot provides four times the power of a hand lance in a compact footprint that contractors can easily move around the jobsite— ideal for work on floors, walls and ceilings.

The Ergo System incorporates: the controller unit, which powers and controls the hydraulics, the Ergo Power Head, which manipulates the high pressure lance, and either the spine or the climber, unique systems used to support and maneuver the power head, based on project needs.

The system exerts an impressive 1,000 newtons of reaction force. The robot can handle higher volumes of water, as much as four times greater reaction force than a human operator with a hand lance.

As Ligchine’s newest laser-guided concrete screed machine, the SCREEDSAVER ELITE equips concrete placing contractors with several new features to optimize jobsite performance. The new laserguided concrete screed features unmatched power, exceptional performance/accuracy, and better job site maneuverability.

• Key to these improvements is its side-shift screed head for screeding around the most difficult obstacles—improving production rates, as operators can easily line up the head when clearing stick-ups that would have required machine tramming.

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The Brokk 70 Demolition Robot

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The Hydra-Screed HS3000 from Curb Roller

Curb Roller Manufacturing’s Hydra-Screed 3000 is a hydraulically powered machine that can be used for large applications such as parking lots or streets as well as patch and repair work.

• Accommodates varying lengths of pipe, custom V-flume, crowned roller screed and numerous other profiles.

• Two-operator machine that is customizable to different job specifications.

• Accommodating any pour width from 3-30 ft. of 6-in. OD 10-gauge pipe or a custom-designed drum for concrete shaping.

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Pettibone’s Traverse T944X Telehandler

The Pettibone Traverse T944X telehandler features an extendable, traversing boom that moves loads by traveling horizontally. Up to 70 in. of horizontal boom transfer allows users to precisely and safely place loads at full lift height through tight openings without having to coordinate multiple boom functions.

With the Traverse, the specified lift height of 44 ft., 6 in. is nearly identical to the 44-ft. landing height. This stands in contrast to a traditional fixed boom pivot, where the true landing height is generally several feet less than the advertised lift height, as operators must account for withdrawing the forks out of the load with enough rearward travel for the fork tips to clear the landing zone. The traversing boom allows for maximum forward reach of 35 ft., 10 in.

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Armed with SmartPower, The Brokk 70—the smallest electric robot in the Brokk range— offers 100% more power than its predecessor, the Brokk 60 II, yet retains the same compact dimensions with only a 133-lbs. weight increase.

With the BHB 105 breaker, the Brokk 70 brings safe, efficient demolition to the most confined spaces and is ideal for a variety of applications and industries.

With SmartPower, the Brokk 70 boasts 9.8 kilowatts of power with a hydraulic output of 5.5 kilowatts, while still maintaining the Brokk 60 II’s compact size and 16-amp fuse. At just 35-in. tall and 23.5-in. wide, the Brokk 70 fits through narrow doorways and into tight spaces, making it ideal for interior demolition applications.

And with a base weight of just 1,235 lbs., it can be transported on an ordinary passenger elevator, making it ideal for top-down demolition projects in urban areas.

As with all Brokk machines, the Brokk 70 offers superior reach and movement. The three-part arm extends to 10.5-ft. vertically and 8.8-ft. horizontally.

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FLATWORK/SLAB

»

BY DAVID ROTHSTEIN, CHUNYU QIAO

Are You Confident in Your Concrete Pavement Mix

DESIGN? T

A fluorescent thin section of concrete in UV light.

All photos and figures courtesy of Chunyu Qiao and DRP, a Twining Company.

New developments in concrete pavement quality assurance can provide important information on the quality, durability, and compliance with mix design specifications.

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he construction of concrete pavements can see unexpected events that require contractors to verify the quality and durability of the in-place concrete.

Such events include exposure to rain during placement, late applications of curing compounds, plastic shrinkage cracking hours within hours of the placement, and problems texturing and curing the concrete. Even when strength requirements and other material tests are satisfied, engineers may call for the removal and replacement of sections of pavement over concerns regarding the compliance of in-place material with mix design specifications. In such cases, petrography and other complementary (but specialized) test methods can provide important information on the quality and durability of concrete mixtures and their compliance with job specifications.

W/CM & CONCRETE QUALITY Professor Duff Abrams first described the relationship between water-cement ratio (w/c) and compressive strength in 1918, formulating what is now known as Abram’s Law: “the compressive strength of a concrete mix is inversely related to its water/cement ratio.” In addition to

controlling compressive strength, the water-cementitious materials ratio (w/ cm), is now favored as it recognizes the replacement of portland cement with supplemental cementitious materials such as fly ash and slag. It is also a critical parameter for concrete durability.

Many studies show that concrete mixtures with w/cm below ~0.45 are durable in aggressive environments, such as areas exposed to freeze-thaw cycles with deicing salts or areas where high concentrations of sulfate are present in soils.

CAPILLARY POROSITY & WHY IT MATTERS Capillary pores are an intrinsic part of the cement paste. They consist of spaces between cement hydration products and unhydrated cement grains that were once filled with water. Capillary pores are much finer than entrained or entrapped air voids and should not be confused with them. When capillary pores are connected, fluids from the external environment can migrate through the paste. This phenomenon is known as percolation and it must be minimized to ensure durability. Durable concrete mixtures have a microstructure where capillary pores are segmented, rather than connected, which occurs when w/cm is less than ~0.45.

Although accurately measuring the w/cm of hardened concrete is notoriously difficult, a reliable method to do so can provide a significant quality assurance tool for investigating hardened in-place concrete. Fluorescence microscopy provides one solution. Here’s how it works.

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FLATWORK/SLAB CONTINUED Figure 1. Examples of fluorescent microscope photomicrographs of the paste from concrete with 0.40 w/c (at top left) and 0.60 w/c (at top right). The lower left photo shows the apparatus for measuring bulk resistivity of a concrete cylinder. The lower right graph shows the relationship between bulk resistivity and w/c.

FLUORESCENCE MICROSCOPY & IMAGE ANALYSIS Fluorescence microscopy is a technique that uses epoxy with a fluorescent dye to illuminate details in a material. Used most commonly in the medical sciences, it has important applications in materials science as well. The systematic application of this method in concrete began in Denmark almost 40 years ago; it was standardized for estimating w/c of hardened concrete in the Nordic Countries in 1991 and updated in 1999.

For measuring w/cm in cementbased materials (i.e. concrete, mortar, and grout), thin sections, or pieces of concrete that measure about 25 microns or 1/1000th of an inch in thickness are made using fluorescent epoxy (figure 2). The process involves cutting tabletshaped pieces of concrete (called billets) that measure about 25 x 50 mm (1 x 2 in.) in area from a concrete core or cylinder. The billets are glued to a glass

slide, placed in a vacuum chamber, and epoxy is introduced while under vacuum. As w/cm increases, so does the connectivity and quantity of the capillary pores, so that more epoxy infiltrates the paste. We examine the thin section under the microscope using a special set of filters to excite the fluorescent dye in the epoxy and filter out extraneous signals. In these images black areas represent aggregate particles and unhydrated cement grains, both with essentially 0% porosity, the bright green circles are voids (not pores) that

have essentially 100% porosity and the speckled green "stuff" between these features is the paste (figure 2, below).

The distinct green color of the paste becomes increasingly brighter as the w/cm and capillary porosity of the concrete increase (see figure 3, page 12).

Image analysis involves the extraction of quantitative data from images. It is used in many different scientific fields, from remote sensing to microscopy.

Each pixel in a digital image essentially becomes a data point. This method allows us to attach numbers to the different brightness levels of green seen in these images. With the revolution in desktop computing power and digital image acquisition in the last 20 or so years, image analysis is now an accessible and practical tool for many microscopists, including concrete petrographers. We routinely use image analysis to measure the capillary porosity of the paste and over time have found strong systematic statistical correlations

Figure 2. Fluorescent light photomicrograph of a thin section indicating aggregate particles, voids (v) and paste. The horizontal field width is ~ 1.5 mm.

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STRENGTH. SUSTAINABILITY. SAVINGS.

Curbing CO2 At The Source

GCP brings together technical expertise, advanced chemistry, and technology to help cement and concrete producers achieve greater strength, sustainability, and savings.

Discover how GCP customers reduced CO2 emissions by 23M tons last year*. Visit gcpat.com/curbing-co2 Copyright 2021 GCP Applied Technologies Inc. All rights reserved. *Reflects GCP internal estimates.

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FLATWORK/SLAB CONTINUED between w/cm and capillary porosity, as shown in figures 4 and 5 (page 13).

Figure 3. Fluorescent light photomicrographs of thin sections showing progressively brighter green paste with increasing w/ cm. These mixtures are airentrained and contain fly ash.

PUTTING IT ALL TOGETHER At the end of the day, demonstrating that concrete in place complies with mix design specifications requires three independent tests. Whenever possible obtain core samples from placements that satisfy all acceptance criteria in addition to samples from placements in question.

Cores from accepted placements can serve as control samples that you can use as a benchmark for evaluating the compliance of the placements in question.

The three-step approach: • Perform petrographic examination per ASTM C856 to verify the components present in the concrete are consistent with mix design parameters. For example, petrography will verify if fly ash or other supplemental pozzolans are present and that the gradation and composition of the aggregate

is consistent with the mix design.

Petrographic examination is also essential to verify that the concrete is well consolidated and that curing is adequate and that there is not an excessive amount of microcracking near the surface that could diminish performance and durability. As part of our petrographic work, we measure w/cm using fluorescence microscopy to verify mix design compliance and durability.

• Measure the volumetric proportions of paste, aggregate, and air voids per ASTM C457 and compare them with volumetric proportions indicated by mix design data. One can also compare volumetric proportions between concrete already accepted for the job and the placements that are in question.

• Measure bulk electrical resistivity per ASTM C1876 and calculate Formation Factor if possible.

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Compare these measurements to verify that the transport properties, and therefore durability, of the questioned placements, are consistent with acceptable placements.

In our experience when reasonable engineers of record see the data obtained from these tests, they are usually amenable to accepting placements provided other key engineering properties (such as compressive strength) are satisfied. By providing quantitative measurements of w/cm and the Formation Factor, we can go above and beyond testing specified for many jobs in showing that the mixtures in question have properties that will translate to good durability.

David Rothstein, Ph.D., P.G., FACI is the principal petrographer for DRP, A Twining Company. Chunyu Qiao, PH.D, the Chief Scientist at DRP, a Twining Company.

References

1. Abrams, D., 1918, Design of Concrete Mixtures, Lewis Institute Structural Materials Research Laboratory Bulletin I, Chicago, IL. 2. T.C. Powers, L.E. Copeland, H.M. Mann, Capillary continuity or discontinuity in cement pastes, The Research Bulletin of the Portland Cement Association 1 (2) (1959) 38–48 Bulletin 110 3. Thaulow N, Damgard-Jensen AD, Chatterji S, Christensen P, Gudmundsson H (1982) Estimation of the compressive strength of concrete samples by means of fluorescence microscopy. Nord Betong 26:2–4 4. Concrete, Hardened: Water-Cement Ratio, NordTest Method NT Build 361, 1991 (2nd Edition, 1999) 5. Weiss, W.J., Barrett, T.J., Qiao, C., and Todak, H., 2016, Toward a Specification for Transport Properties of Concrete Based on the Formation Factor of a Sealed Specimen, Advances in Civil Engineering Materials, vol. 5, no. 1; DOI: 10.1520/ACEM20160004 6. Archie, G. E., 1942, “The Electrical Resistivity Log as an Aid in Determining Some Reservoir Characteristics,” Petrol. Technol., Vol. 146, No. 1, pp. 54–62.

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FLATWORK/SLAB » BY MICHELLE WILSON An Inside Look at the Updates in ACI 301-20 A breif overview of the updates to ACI 301-20: Specifications for Concrete Construction.

American Concrete Institute

A

CI 301-20: “Specifications for Concrete Construction,” published by the American Concrete Institute (ACI), sets forth criteria for concrete construction that guide contractors in their daily work. The specification is commonly incorporated by reference into contract documents by the architect or engineer (A/E).

In October 2020, ACI published an expanded and revised version of the specification, including a title change. The new title, “Specifications for Concrete Construction”, recognizes that the specification covers diverse topics including industrial floor slabs and architectural concrete.

Two checklists for incorporating ACI 301 into concrete specifications are included. The first of these checklists indicates specific qualities, procedures, and performance criteria that the specifier must include in a project specification that are not defined in ACI 301-20, while the second checklist identifies choices and alternatives that the specifier can include as requirements in a specification.

WHAT’S NEW

Section 1—General Requirements: • New definitions were added for clarity. Definitions of specialty concrete applications covered in separate sections were removed.

• Optional requirements include a preconstruction conference to review project requirements, acceptance criteria, and responsibilities.

• Shotcrete is now included in the scope.

Section 3—Reinforcement and Reinforcement Support: • Zinc-coated (galvanized) reinforcing bars for structures designed in accordance with ACI 318-19 must still conform to ASTM A767/A767M. However, zinc-coated reinforcement conforming to ASTM A1094/A1094M may now be specified for applications where a lesser zinc coating thickness is permitted.

Section 4—Concrete Mixtures:

• Requirements for slump flow of self-consolidating concrete (SCC) were separated from slump requirements for other concrete mixtures. Also, if specified, passing ability and static segregation should be evaluated in accordance with ASTM C 1621 and ASTM C1610, respectively.

• Minimum cementitious materials requirements for floors were removed, providing more flexibility in designing concrete mixtures.

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• Timelines for the prequalification of aggregates were extended. Data on types, sizes, pit or quarry locations, producers’ names, aggregate supplier statement of compliance with ASTM C33, and ASTM C1293 expansion data must be no more than 24 months old.

• Crushed hydraulic-cement concrete or recycled aggregate may be permitted if documentation is provided as required by the A/E and its use is determined suitable.

• Mineral fillers, conforming to ASTM C1797, are now permitted provided they are obtained from the same sources and consist of the same types as those used in concrete represented by submitted field test records or used in trial mixtures.

• If Modulus of Elasticity is specified, test data for proposed mixtures must be submitted. The average of at least three cylinders from the same concrete sample, tested at 28 days, must meet or exceed the specified value.

• Lightweight aggregate for internal curing is limited to prewetted fine aggregate conforming to ASTM C1761.

• Aggregates determined to be susceptible to alkali-carbonate reactions per ASTM C1778 testing are not allowed.

• Limitations imposed on concrete mixtures to be qualified to reduce the potential of alkali-silica reactivity were revised; adding a requirement for submitting supporting data for each aggregate showing expansion in excess of 0.10% at 16 days when tested in accordance with ASTM C1260, and defining limits for expansion and alkali content based on level of aggregate reactivity.

Section 5—Handling, Placing, and Constructing:

• For cold weather placements, unless otherwise specified, metallic items in concrete formwork must be above 10˚ F, and contact surface temperature of ground, subbase, or mud mats has to be above 32˚ F. • For integrating high-strength concrete with floor systems, high-strength concrete should extend through the full floor system depth at least 2 feet past each face of columns and walls to achieve a monolithic mass.

Addtional updates include sections 6, 8, 9, 11, 12, 13 and 14. The new ACI 301 provides the latest construction practices and concrete-related material information necessary for today’s contract documents. If contractors and other industry personnel are not well-versed in the changes incorporated in ACI 301-20 it can have a negative impact on a project’s budget and schedule. ACI Specifications for Concrete Construction and the ACI Field Reference Manual are both available in printed and digital formats.

Michelle L. Wilson is Senior Director, Cement and Concrete Technology, Portland Cement Association and Chair of ACI Committee 301 during the 2016-2020 document cycle.

Find an expanded look at the updates at ForConstructionPros.com/21319401.

www.ForConstructionPros.com/Concrete

4/7/21 10:14 AM

THE STINGER The Stinger electric flex shaft vibrator is rugged, lightweight, and powerful. The 115v electric motor has been designed to run cool with the power and torque to handle todays concrete loads.

The stinger attaches to competitor core and casing with quick disconnect adapters.

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NEW PRODUCTS

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• Customizable to multiple languages • Classify vehicles and apply weight limits • Fully document and compare vehicles by vehicle identification • Automate calibration, operation, and report generation ForConstructionPros.com/21204114

Milwaukee MX FUEL CARRY-ON 3600W/1800W Power Supply

The 49.7-lbs. MX FUEL CARRY-ON 3600W/1800W Power Supply provides 3,600 peak watts and 1,800 running watts of pure sine wave energy to power everything from high-demand 15A tools to sensitive electronics. Its compact size, zero emissions and quiet operation allow it to safely operate in confined, indoor spaces, while a roll cage provides durability for outdoor jobsite use. A push button start enables startup in seconds. The unit delivers enough power to run one 15-amp tool and one lower wattage device simultaneously. It can be powered by a single battery or two batteries for double the run time. The kit includes the power supply, MX FUEL REDLITHIUM XC406 Battery Packs and a detachable charger cord.

ForConstructionPros.com/21206838

Command Alkon’s Water Add Meter

Command Alkon’s Water Add Meter (WAM) measures the amount of water added before and during the pour to help validate concrete quality.

The Water Add Meter is mounted onboard the mixer truck to automatically capture an accurate, real-time record of water added to the load once in the drum of the mixer truck. Eliminate the need for manual documentation while ensuring consistent, quality material is delivered to the jobsite each and every time. Command Alkon has made the Water Add Meter can be purchased as an option in conjunction with the TrackIt, TFleet, or COMMANDassurance systems.

When further integrated with COMMANDbatch, Command Alkon’s ready mix plant automation solution, the Water Add Meter allows for calculation of W/C ratio throughout the delivery cycle. The meter comes packaged with plumbing kit, fittings, clamps, and a step-by-step installation guide.

Two models are available: • WAM-350 allows water addition information to be read directly on the meter on easy-to-read display or on in-cab display.

• WAM-300 has the same functionality as the 350 model but without the digital display on the meter.

The hardware is tough enough to withstand the demanding conditions that ready mix fleets operate in, featuring a weather resistant brass core and sacrificial endcaps that reduce the risk of meter damage in the event that the lines are not cleared in freezing conditions.

ForConstructionPros.com/21233318

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With Procore BIM and the Dynamic Wall Elevations feature, users can quickly generate elevations, or lift drawings, instantly in the field.

• Lets users zoom in and out and analyze dimensional relationships down to 1/8th of an inch • Select any object to get the centerline or outside dimensions to grids and levels to validate that everything is installed exactly per the coordinated model • Reduced rework means safer projects and cost savings ForConstructionPros.com/21202261

Updates to the AP Office and AP Mobile Platfomrs of the ACCUPOUR Volumetric Mixer Productivity

Cemen Tech’s ACCU-POUR has a major update for platform components AP Office and AP Mobile.

New functionalities include electronic signature to text and/or email an electronic batch ticket to your customer and your office, credit card preauthorization to place a hold on funds for a job to ensure customer’s credit card has sufficient funds, and ACCU-POUR generated invoices now display Mix Design and Purchase Order.

With AP Office and AP Mobile working jointly in real-time, information goes to the unit and then directly back to the office. After an order is placed, dispatch enters the job parameters into AP Office. AP Mobile then receives those parameters and wirelessly sends all information to the mixer. All production data is automatically sent to AP Office for analysis.

AP Office also simplifies assignments and orders by allowing users to create one order, then divide it into multiple trucks if needed and still track under one job. With smart scheduling, users know where their fleet is at any time and where they are going next if adjustments are needed before the next job begins.

C D T B S N C

Ch in as

W Bu yo to

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4/7/21 10:18 AM

ch

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4/7/21 10:18 AM

FOUNDATION & WALLS

»

Part 2

BY KIM BASHAM, PHD PE FACI

A Summary of Concrete Crack Repair Options Sometimes cracks require repairing but with so many options, how do we design and select the best repair option? It’s not as difficult as you may think.

C

oncrete cracks. That’s a fact.

After investigating the cracks and establishing the repair objectives, designing or selecting the best repair material and procedure is fairly straight forward. This summary of crack repair options addresses the following procedures: clean and fill, rout and seal/ fill, epoxy and polyurethane injection, autogenous healing, and “no repair.”

INVESTIGATING CRACKS As discussed in "Part I: How to Evaluate & Troubleshoot Concrete Cracks," investigating cracks and determining the root cause of the cracking is the key to selecting the best crack repair option. Briefly, the critical items needed to design a proper crack repair are average crack widths (including minimum and maximum widths) and determining if the cracks are active or dormant.

Of course, the objective(s) of the crack repair is just as important as measuring crack widths and determining the potential for future crack movements.

Active cracks are moving and growing. Examples include cracks resulting from continuing ground settlement or cracks acting as contraction/expansion joints for the concrete element or structure. Dormant cracks are stable and future movements are not anticipated.

Typically, cracking caused by concrete drying shrinkage will be active at the

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beginning but eventually stabilize and become dormant as the moisture content of the concrete stabilizes. Also, if there is sufficient reinforcing (steel rebar, steel fibers, or macro-synthetic fibers) crossing through cracks, future movements are controlled and cracks may be considered dormant.

For dormant cracks, use either rigid or flexible repair materials. Active cracks require flexible repair materials and special design considerations to allow for future movements. Using a rigid repair material for active cracks typically results in cracking of the repair material and/or the adjacent concrete.

Of course, it is important to establish the cause of cracking and to determine if the cracks are structurally significant or not. Cracks indicating there may be a design, detailing, or construction error raise concerns about the

Photo 1. Using a needle tip mixer (14, 15 and 18 gauge), a low viscosity repair material can easily be injected into hairline cracks without routing Photo Credit: Kelton Glewwe, Roadware, Inc.

load-carrying capacity and safety of the structure. These types of cracks may be structurally significant. Cracking can be load-induced or related to intrinsic volume changes of the concrete such as drying shrinkage, thermal expansion, and contraction and may or may not be significant. Before selecting a repair option, identify the cause and consider the significance of the cracking.

Repairing cracks caused by design, detailing, and construction errors is beyond the scope of a simple article.

This situation typically requires a comprehensive structural analysis and may require special strengthening repairs.

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FOUNDATION & WALLS CONTINUED

NO REPAIR Sometimes “no repair” is the best repair option. Not all cracks require repair and monitoring the crack may be the best choice. If needed, the crack can be repaired later.

CRACK REPAIR OPTIONS

Clean and Fill

Figure 1. As the shore hardness number of a material increases, the hardness or stiffness of the material increases and the flexibility decreases.

To prevent crack edge spalling of cracks exposed to hard-wheeled traffic, a minimum shore hardness of about 80 is required.

Photo Credit: Kim Basham

REPAIR OBJECTIVES Restoring the structural soundness or integrity of a concrete member, stopping water leaks or sealing out water and other harmful elements such as deicing chemicals, providing crack edge support, and improving the appearance of the crack are common repair objectives.

Considering these objectives, repairs can be loosely divided into three categories: • Integrity repairs: Restoring the element to the original strength and stiffness, • Sealing/filling, and

• Cosmetic repairs.

With the popularity of exposed and architectural concrete, the demand for cosmetic crack repairs is increasing.

Sometimes integrity repairs and crack sealing/filling are required to be cosmetic repairs too. Before selecting the repair technique, be sure to clearly establish the objectives of the crack repair.

Before designing a crack repair or selecting a repair procedure, there are four key questions that must be answered. Once these are answered, it will be easier to select a repair procedure option.

• What are the average, minimum, and maximum crack widths?

• Are the cracks active or dormant?

• Is the repair an integrity repair or crack sealing or filling?

• Is the repair a cosmetic repair?

This simple technique has become popular, especially for architectural type repairs because of the very low viscosity repair materials that are now available.

Because these repair materials can easily flow into very narrow cracks via gravity, no routing (i.e., installing a square or V-shaped sealant reservoir) is required.

Since no routing is required, the final repair width is the same as the crack width which is less noticeable than routed cracks. Also, cleaning with a wire brush and vacuum is considerably faster and more economical than routing.

First, the crack is cleaned to remove dirt and debris, and second, filled with a low viscosity repair material.

Manufacturers have developed very small diameter mixing nozzles attached to hand-held, dual-cartridge guns to install repair materials (photo 1, page 18). If the nozzle tip is larger than the Photo 2. Using clear adhesive tape, drilled holes, and a rubber-tipped mixing tube attached to a hand-held, dual-cartridge gun, a repair material can be injected with low pressure into hairline cracks.

Photo Credit: Kelton Glewwe, Roadware, Inc.

➌

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Photo 3. Routing and sealing consist of first cutting a sealant reservoir with either a square or V-shaped blade and filling with an appropriate sealant or filler. As shown, the routed cracking is being filled with a polyurethane and after curing, it was scraped flush with the surface.

Photo Credit: Kim Basham

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4/7/21 10:29 AM

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FOUNDATION & WALLS CONTINUED

Photo 4. Before injecting epoxy, the surface of the crack must be capped with non-sag epoxy to confine the pressurized epoxy. After injection, the epoxy cap is removed by grinding.

Typically, cap removal leaves grind marks in the concrete.

Photo Credit: Kim Basham

Figure 2. Increasing the width versus depth ratio will increase the sealants ability to tolerate future crack moments. Use 1:2 (0.5) to 1:1 (1.0) shape factor or as recommended by the manufacturer of the sealant for active cracks to ensure the material can properly stretch with future crack width growth.

in units of centipoise, as viscosity's value decreases the material becomes thinner or flows more easily into narrow cracks. A simple, low-pressure injection process can also be used to install repair materials (see photo 2, page 20).

Rout and Seal/Fill This is the most common procedure to repair isolated, fine, and large cracks (photo 3, page 20). It is a nonstructural repair that consists of enlarging the crack (routing) and filling it with a suitable sealant or filler. Depending on the size and shape of the sealant reservoir and the type of sealant or filler used, routing and sealing can repair both active and dormant cracks. This method

Photo Credit: Kim Basham

crack width, some crack routing may be required to create a surface funnel to accommodate the size of the nozzle tip. Check the manufacturer’s literature for the viscosity; some manufacturers state the minimum crack width that is appropriate for the material. Measured

is ideal for horizontal surfaces but can also be used for vertical surfaces with non-sag repair materials.

Appropriate repair materials include epoxies, urethanes, silicones, polyureas, and polymer mortars. For slabs, designers must choose a material with suitable flexibility and hardness or stiffness properties to accommodate both the anticipated floor traffic and future crack movements. As the flexibility of the sealant increases, tolerance to crack growth and movement increases but the load carry-capacity of the material and crack edge support decreases. As the hardness increases, load carry-capacity and crack edge support increase but the crack movement tolerance decreases.

SUMMARY OF CRACK REPAIR OPTIONS Repair Method

Active Cracks

Clean and Fill Routing and Sealing/Filling

X

Autogenous Healing

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X

Structural Repair

Crack Sealing

X

X

X

X

X

Epoxy Injection Polyurethane Injection

Dormant Cracks

X

X

X

X

X

X

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4/7/21 10:30 AM

Zero Turn for Mobility

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FOUNDATION & WALLS CONTINUED For dormant cracks in floors with hard-wheeled traffic, harder repair materials (fillers) are preferred because of the better crack edge support as illustrated in figure 1 (page 20). For active cracks, flexible sealants are preferred but the load-carrying capacity of the sealant and crack edge support is less. Shore hardness numbers are related to the hardness

(or flexibility) of a repair material. As the shore hardness number increases, the hardness (stiffness) of the repair material increases and the flexibility decreases.

For active cracks, the size and shape factor of the sealant reservoir is just as important as selecting a suitable sealant that can accommodate future anticipated crack movements. The shape factor is the

depth to width ratio of the sealant reservoir. In general, recommended shape factors are 1:2 (0.5) and 1:1 (1.0) for flexible sealants (figure 2, page 22). Reducing the shape factor (by increasing the width relative to the depth) will decrease the sealant strain caused by crack width growth. If the maximum sealant strain is reduced, the amount of crack growth the sealant can tolerate increases. Using the manufacturer’s recommended shape factor will ensure maximum elongation of the sealant without failure. If needed, install a foam backer rod to limit the depth of the sealant and to help form the “hour-glass” elongated shape.

Photo 5. Polyurethane injection consists of drilling holes, installing injection ports and pressure injecting resin. The resin reacts with moisture in the concrete forming a stable, flexible foam that seals cracks, even leaking cracks.

Photo Credit: Kim Basham

The allowable elongation of the sealant decreases as the shape factor increases. For a 6-in. thick slab with a full-depth 0.020-in. crack, the shape factor without a sealant reservoir is 300 (6.0 in. / 0.020 in. = 300). This explains why active cracks sealed with a flexible sealant without a sealant reservoir commonly fail. Without the reservoir, the strain quickly exceeds the tensile capacity of the sealant if any crack growth occurs. A sealant reservoir with a shape factor as recommended by the manufacturer of the sealant should always be used for active cracks.

Epoxy Injection Epoxy injection bonds or welds cracks as narrow as 0.002 in. together and restores the concrete’s integrity including

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between 0.004 in. and 0.008 in. The healing process is due to the hydration of unhydrated cement particles that are exposed to moisture and the formation of insoluble calcium carbonate on the surface of the crack created by leaching of calcium hydroxide from the cement paste to the surface that reacts with the carbon dioxide in the surrounding

Polyurethane Injection

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It is a natural process of crack repair that occurs in the presence of moisture for cracks with maximum widths

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A-

Polyurethane resins can be used to seal wet and leaking cracks as narrow as 0.002 in. This repair option is primarily used to stop water leaks and consists of injecting a reactive resin into cracks that combines with water to form an expanding gel that chokes off the leak and seals the crack (photo 5, page 24).

These resins will chase the water and penetrate into tight micro-cracks and pores of the concrete creating a firm bond to the wet concrete. Also, cured polyurethanes are flexible and will tolerate future crack movements. This repair option is permanent and works with either active or dormant cracks.

air. A 0.004-in. wide crack can heal after several days and a 0.008-in. crack may heal in several weeks. Healing will not occur if cracks are subjected to fastflowing water and movements.

CR DE

g

strength and stiffness. This method consists of applying a surface cap of non-sag epoxy to confine the crack, installing injection ports into drilled holes at close intervals along horizontal, vertical or overhead cracks, and pressure injecting epoxy (photo 4, page 22).

Tensile strengths for epoxies exceed 5,000 psi. For this reason, epoxy injection is considered a structural repair.

However, an epoxy injection will not restore as-design strengths nor strengthen concrete cracked due to design or construction errors. Seldom will injecting cracks with epoxy resolve issues associated with load-carrying capacity and structural safety concerns.

Epoxy injection is a rigid, full-depth repair where the injected crack will be stronger than the adjacent concrete.

If active cracks or cracks acting as contraction or expansion joints are injected, expect other cracks to form next to or far away from the repaired crack.

Only inject dormant cracks or cracks that have sufficient amounts of reinforcing crossing the crack so future movements are restrained. The table on page 22 summarizes the important selection features of this and the other repair options.

95 1926-2021

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FOUNDATIONS & WALLS

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BY GUY ERICKSON

Moving from 2D to 3D Formwork

PLANNING

The concrete industry is becoming increasingly competitive as a growing number of contractors adopt tools, such as BIM and collaboration platforms, for managing project information.

F

ormwork is one of the most costly, labor-intensive and time-consuming phases of the concrete construction process. Under increased pressure to complete projects on time and budget, rethinking how formwork is planned can help concrete contractors outperform the competition, work more efficiently and meet modern project demands.

There was a time when drawing or copying and pasting CAD blocks in 2D was the only way to create formwork layout plans. Even today, as much of the construction industry has adopted 3D modeling, many concrete contractors continue to rely on information and documents produced using 2D CAD. With his approach, formwork is disconnected from other

construction-planning tasks, resulting in a lack of information and errors.

Whether on paper or a computer, using 2D to plan formwork increases the potential for error, guesswork and risk. It’s impossible to capture and deliver all of the information of an actual, three-dimensional structure in 2D. For example, 2D can’t reflect all aspects of a project as they exist in real life. When relying on 2D, the information needed for timely, highquality formwork planning is often lowquality or missing from design drawings altogether. What’s more, 2D makes it difficult to spot potential errors before they turn into costly rework.

IMPROVING FORMWORK PLANNING AND DETAILING WITH 3D For concrete contractor F.A. Wilhelm, working with a constructible 3D model has increased accuracy and accelerated formwork planning.

“We use Tekla Structures as a single solution for our formwork detailing, planning and project execution," says Adam Joraanstad, formwork detailer.

“We can estimate, design and plan our formwork more efficiently and discover potential pitfalls earlier on in the process.”

Moving from 2D CAD to 3D can take formwork planning to the next level and open the door to more efficient, accurate and productive projects by: • Automating takeoff: 3D modeling allows for instant material takeoffs and automatically provides correct areas for different formwork types during planning and estimating.

When using BIM, the model and takeoffs are connected, meaning that formwork area quantifications can be visualized in 3D and organized according to location, pour type, sequence and planned formwork type.

This allows contractors to include formwork line items in budgets for more accurate, reliable estimates.

• Streamlining processes: With effective modeling tools pour geometry can be modeled and used to allow for placing of formwork components and accessories, such as ties and clamps automatically. And, because all reports and drawings are generated from the model, and changes are automatically updated to all documents, the risk of human error is significantly reduced When using BIM, the model and takeoffs are connected, meaning that formwork area quantifications can be visualized in 3D and organized according to location, pour type, sequence and planned formwork type.

Photos courtesy of Tekla

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FOUNDATIONS & WALLS CONTINUED

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Using tablets, installation teams can access 3D formwork models and associated, up-to-date information and documents in the field.

compared to manual, disconnected 2D workflows. Creating a model with detailed and constructible information means contractors can proceed quickly and securely to the construction phase, with far less manual work.

• Assessing Constructibility: Rather than discovering problems in the field when it’s too late, 3D visualization makes it easier to detect clashes and resolve potential constructability issues early in the process. With a 3D model the question, “can we build this?” can be answered at a glance.

Similarly, pours can be planned and construction quality quantities automatically reported just by adding

pour breaks to the concrete model.

• Communicating requirements to the field: 3D models help everyone on site quickly and easily understand formwork requirements.

Using tablets, installation teams can access 3D formwork models and associated, up-to-date information and documents in the field. Having this information readily available removes any guesswork and greatly reduces requests for information, unproductive work and the potential for error. It also makes it easier for contractors to ensure that construction work is progressing as planned.

LOOKING AHEAD The concrete industry is becoming increasingly competitive as a growing number of contractors adopt tools, such as BIM and collaboration platforms, for managing project information. Those still using traditional methods might be

www.ForConstructionPros.com/Concrete

CONC0421_26-29_Foundations3D.indd 29

comfortable today, but as their competitors complete bids and projects faster, easier and with better accuracy and quality, they will soon find that it’s time to catch up.

Moving to 3D formwork planning and detailing opens the door to working smarter and faster. With 3D formwork planning, contractors can create formwork drawings, deliver the right information to workers in the field and spot problems before it’s too late. This minimizes risks, improve productivity and reduce construction costs through more accurate estimating and planning, efficient management of high-quality information and streamlined coordination and communication.

Guy Erickson is a business manager at Trimble, Structures Division.

Find this article online at ForConstructionPros.com/ 21197972.

APRIL/MAY 2021

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PRODUCT FOCUS

CONCRETE PUMPS & PLACEMENT EQUIPMENT

Strong Mfg.’s FloorMate80E

Small jobs? No problem. With an all-new fully electric model, the FloorMate80E leaves no footprint on where it has been. Designed to be a zero-emission and a non-consumable machine, the FloorMate80 gives the customer full access to working indoors safely.

FloorMate80 has vertical heights of over 100 ft. and an output ranging from 10 to 30 GPM. It is paired with Mitsubishi for its electronics, having a control system with a fail rate of fewer than 100 parts per million.

Wirtgen WPS 62i Concrete Placer/Spreader

The WPS 62i/WPS 62 two-track placer/spreader is designed to efficiently feed concrete from the side and spread it homogeneously in front of the slipform paver. Trucks feed the concrete from the side, which the placer/spreader then evenly distributes over the entire working surface. Two different working widths are available between 12 and 24 ft.

With both sizes, concrete can be laid up to 20-in. thick. The hydraulically telescoping machine frame and concrete scraper unit enable the unit to be easily adapted to the jobsite. The fully modular design with standard hydraulic quickchange couplings enables it to be easily converted and quickly prepared for transport to the next location.

ForConstructionPros.com/21259897

Minnich 50cc Gaspowered Back Pack Concrete Vibrator

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The 20.5-lbs. vibrator is designed to maximize operator comfort, mobility and productivity during concrete consolidation.

• Powered by a Honda 50 cc motor • Includes a removable throttle assembly that enables operator to relocate the throttle for easy operation • Core/casings and vibrator heads interchangeable between all of the company’s gas-powered and electric flex shaft units • True universal quickdisconnect system provides equipment flexibility

The Revolution Boom on the S 36 X Truck-mounted Concrete Pump

Schwing’s boom technology takes the concrete pumping business to new levels. The Revolution boom on the S 36 X truck-mounted concrete pump offers maneuverability and speed, with continuous 360-degree articulation of the tip section and unprecedented 330-degrees of articulation of the third section. Hydraulic motors replace the last two cylinders of the four-section boom to provide the additional coverage.

• The 36 X with Revolution boom provides 115 ft., 6 in. of reach • Compact X-style outriggers set-up with a 20-ft., 5-in. outrigger spread • The 730-degree slewing range (365 left and 365 right) aids in fast set-up and versatility to overcome jobsite obstacles • The standard 2025H-5 pump kit offers 178 cu. yds. per hour output and 23 strokes per minute • Boom operation is through the Vector Control system that provides wireless proportional joystick control

ForConstructionPros.com/21102526

110 D-K Crawler Concrete Pump

ForConstructionPros.com/21050764

Miller Formless M-8800 Slipforming System

The M-8800 can pour up to 102-in. barrier walls and bridge parapet walls and up to 20-ft. in straddle or side-mount configuration.

• 173-hp Tier 4 Final diesel engine • Latest generation MFS Control System includes sensors and handheld remote and is 3D ready • Four tracks with independent steering and two-speed hydraulic drive motors • Includes a 10-spool vibrator control, hydraulic frame widening (48 in.), heavy-duty dual transfer augers, 45-in. elevation tubes, high-volume water wash down system and triple grouser track pads • Standard machine pours in right- or left-hand configuration

The 16,424-lbs. 110 D-K features sturdy construction, can be flexibly maneuvered and has been specially developed for concrete pile foundations in combination with a drilling rig.

• Maximum concrete output of 133 cu. yds. per hour and 1,088-psi maximum concrete pressure • 194-hp six-cylinder Tier 4 Final engine • Open hydraulic circuit • Can communicate via radio with the company’s drilling rigs ForConstructionPros.com/21107584

ForConstructionPros.com/21093588

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4/7/21 10:39 AM

© 2021

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PRODUCT FOCUS

»

BY JONATHAN KOZLOWSKI

A Mixer & Pump You Can Use INDOORS It's this innovative mentality that inspired Strong to provide a zero-emission solution to their customers to be able to work indoors - the FloorMate80E. “It’s not just a pump.

It’s a mixer and a pump together, like a mobile batch plant,” says Jesse Downs, sales representative of Strong Manufacturing.

Strong Manufacturing

L

et's say you have a project indoors. The emissions caused by a gasoline-, diesel-, or propane-powered mixer/pump would force you to figure out a way to get the slurry to where you need it. What if you could bring that machine inside? What if you could set it alongside your workers and work the floor your on as well as the 10 floors above? With the latest from Strong Manufacturing, you can.

As an innovator in the design and manufacturing of mixing and pumping equipment of cement and gypsum-based products, the company has developed a solution that allows a contractor to not only run the machine inside but it even fits through the door. The company sees its innovative spirit within its 60+ years of experience and versatility—enhancing the company's ability to design specialty equipment for any need. Case in point, they are the original designer and manufacturer of the first automated mixer for lightweight concrete for aircraft arrestor runway systems.

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“With it being electrical, all they have to do is find one plug,” he says. Instead of a diesel engine or hydraulic pump, the FloorMate80E can operate on a standard 220 single-phase outlet plug—the same outlet that runs a household oven or dryer. If no such electric connection exists, the FloorMate80E can run off of a 220V single phase 30-amp generator via an extension cord. Aside from bringing zero emissions to the jobsite, the allelectric pump and mixer combination removes a litany of equipment that all come with consumption costs.

• No hydraulic oil • No fuel (diesel, gasoline, propane) • No oil filters • No fuel filters • No hydraulic filters ELECTRIC EFFICIENCY The machine itself features a double drum mix system—much like interlocked fingers being pulled apart, explains Downs. “That's basically what our mixer does to the material. It gives it a shear which gives it a better mix,” he says.

Reportedly, this process gets the job done quickly, capable of mixing at an efficient 2.5 minutes and pumping at presets of 10, 20, and 30 gallons a minute.

The FloorMate80 is a floor-by-floor basis, meaning one floor at a time due to the limitations of the length of the standard rotor-stator and the motors required to turn it. Going electric, Strong Manufacturing was able to increase the electric motor size which gave the torque needed to turn over a full-length rotor/stator. “What this does for the customer is gives them more pressure of the rotor/ stator. This is what you need to push the material further such as horizontal and vertical,” says Downs.

The FloorMate80E was designed to fit through standard doorways and through elevator shafts. While compact, however, the output pressure can send the slurry up 10 floors versus the traditional one.

“This becomes profitable because, to do those heights, a standard machine may run you in the $70k+ range—this unit comes in less than half that cost,” he says.

As strange as it sounds to say, it’s basically an eco-friendly mixer and not only because of the loss of emissions.

While it’s not replacing the larger pumps, using the FloorMate80E in the right situation can save transport costs as well. “If you have a small job, you don't need to pull your big pump out.

You can put this in a bed of a truck, put it on a load trailer, and roll it out there.”

For more information on concrete pumps, visit ForConstructionPros.com/ concrete/equipment-products/ concrete-pumps.

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COVER STORY

»

BY GIGI WOOD

SQUARENESS & PLUMB:

Thermal Mass Creates Home of the

FUTURE

W

ith its long history of concrete experience, Purinton Builders of Connecticut is not one to shy away from new challenges.

Started in 1984, general contractors Dennis Purinton and his son, Michael Purinton, have made a name for themselves through the success of their cast-inplace concrete projects. The company has continually pursued the latest technology

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in the field, with a desire to create highquality walls and foundations, as well as environmentally friendly mix designs.

Actively involved in the industry, Dennis Purinton has kept his pulse on the latest concrete innovations throughout the years. He’s served as president of the Concrete Foundations Association (CFA) from 2016-2018. He was named Contractor of the Year in 2007 by the National

Concrete Foundation Association and was a voting member on American Concrete Institutes’ committees for cold weather concreting and residential concrete.

Now he’s got another accolade on his belt. One of Purinton’s recent jobs, a single-family custom home with removable concrete forms, was awarded the CFA 2020 Best Projects of the Year in the Above-Grade Concrete Home

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Concrete Foundations Association

This concrete home in Connecticut was awarded the CFA 2020 Best Projects of the Year in the AboveGrade Concrete Home category.

Photo Credit: Concrete Foundations Association

PLANNING REQUIRED “When you build a concrete house, you have to put a tremendous amount of thought in upfront,” Purinton says.

“The builder, the owner, the architect and I sat down with all of these people before one piece of pencil lead hit a paper. One of the things I explained to them is you have to design everything upfront. You have to know where everything goes before we even start. This is not cavity wall construction. This is not building out of toothpicks. There is no cut and hack afterward to make it fit.

You really have to get your act together.”

They spent three months designing the project as completely as possible.

“We were getting everything laid out so that we knew where everything was going to go and how we were going to do it,” he says.

category. The project client had asked for an energy-efficient home, and Purinton convinced the builder and architect to take a chance and construct the 2,900-sq.-ft. structure with concrete, relying on concrete’s thermal mass.

“The owner was interested in a highperformance, energy-efficient building shell,” Purinton says. “The option for concrete with a cast-in-place insulation system became appealing.”

TIGHT SQUARENESS AND PLUMB They used self-consolidating concrete and cast-in-place techniques with sandwich wall construction in the house design. The client chose the Thermomass system over insulated concrete forms (ICFs), so Thermomass System CIP was used in the construction, with the Thermomass rigid insulation in the center of the castin-place walls. Thermomass provided engineering data for use in the wall construction, Purinton says.

“All the house walls above and below grade have the 4-in. Thermomass CIP Insulation system, which is a system of casting in place a layer of insulation within two layers of separated concrete, structurally secured,” he says. “It was important that the concrete was a selfconsolidating mix, given the heights of the placements and the tightness of the details for the thinner concrete wall portions.”

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PROJECT STATS Size: 2,900 sq. ft.

Amount of wall: 738 li. ft.

Concrete volume: 255 cu. yds.

• 13,000 lbs. of steel reinforcement • 180 lbs. microfiber slab reinforcement • 6,000 sq. ft. 4-in. Thermomass CIP XPS insulation Wall heights: 4, 9, 10, 11 ft.

Wall thicknesses: 8-12 in.

The Thermomass system capitalizes on concrete’s greatest asset, its thermal mass effect, to create a building envelope that controls heat capture.

Thermomass insulation connects two wythes, or layers of concrete, to transfer loads to the structural wythe.

“Basically, what you have is a layer of concrete on the outside, then you have insulation and then have a layer of concrete on the inside,” Purinton says.

“In the wintertime, the interior concrete or the interior wythe, stores the heat for a temperature between 60º and 70º F. That's where you're taking the heat of the sun and you're storing it in that concrete until later in the day. When the ambient temperature outside starts to drop, the concrete puts that heat back into the structure.”

The opposite happens during warmer months. “In the summertime, the exterior wythe of concrete absorbs the heat of the sun, protecting the insulation that protects the interior wythe,” he says. “What it does is it absorbs all that heat all day long and then dumps it at night when the temperature goes down. So, both wythes of concrete act differently depending on the season and what you want it to do. That's why it's important to put insulation in the center of the wall.”

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COVER STORY CONTINUED

The Thermomass system capitalizes on concrete’s greatest asset, its thermal mass effect, to create a building envelope that controls heat capture.

Thermomass insulation connects two wythes, or layers of concrete, to transfer loads to the structural wythe.

Photo Credit: Concrete Foundations Association

In this system, the electrical wiring in perimeter walls was installed before placing the walls, which constricted normal concrete flow, Purinton says.

“Detailing was an important consideration as all windows and doors were to be attached to the concrete,” he says.

“That meant that the openings were critical in both squareness and plumb.”

NEGATIVE HERS INDEX SCORE The house incorporates several energyefficient technologies, such as solar panels and geothermal energy. Those factors, combined with the use of the concrete thermal mass, made the building project stand out, Purinton says.

“The house is expected to be net-zero in energy consumption,” he says. “The combination of the concrete’s thermal mass, extremely low air inflation (0.05% air changes), and geothermal wells make this home very efficient.”

The structure’s Home Energy Rating System (HERS) Index is negative. Most homes have a HERS Index of 0-150; a higher rating denotes lower energy efficiency. According to the U.S. Department of Energy, a typical resale home scores a 130 on the HERS Index, for example. Purinton notes that the results from the blower door test were "spectacular." Conducted on the house to test the building’s air leakage and energy consumption, they exceeded expectations.

When constructing a house with such a tight design, he suggests that contractors should pay close attention to

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the HVAC system. “The HVAC person is extremely important in this," he says.

Purinton jokes that without a properly designed and installed HVAC system in a concrete house reliant on thermal mass, “if you cook a lobster in July, you’re going to smell it at Christmas.”

In a house as tight as this concrete one, there is a low rate of air changes per hour.

“A normal builder is used to building something that leaks like a sieve and doesn't have to really worry about air quality,” he says. “Air quality in a concrete house is extremely important. And the HVAC contractor needs to understand that the size of the heating and cooling equipment has to be substantially smaller, or it will short cycle and burn itself up. Building a correct concrete house involves a lot more than what a normal builder is used to working with.”

A HOUSE FOR THE JETSONS The most interesting part of the house is its technology, not its concrete walls, Purinton says.

“The house is very unique; it’s past the house of the future,” he says. “When I say past it, I truly mean it. This house is, even though it's very plain looking, I would compare it to something of the Jetsons.”

There are no light switches, for example. The lights are controlled by sensors. “When you enter a room, a sensor knows that you entered the room,” he says. “It knows the time of day. It senses the amount of natural light that's available.”

The technology learns the residents’ habits and adjusts accordingly. “If you get up in the middle of the night, before your feet hit the floor, it senses that you have moved,” Purinton says. “It turns on the appropriate number of lights to the correct hue so that you don't wake up your spouse, but yet you don't trip over the dog on your way to the bathroom.

The technology in this house is just mind boggling and it’s the house of the future because of the thermal mass, low air infiltration, and geothermal wells make this home extremely efficient.”

FINDING THE RIGHT BUILDER The key to the project’s success, Purinton says, was finding the right builder; someone willing to take a chance on the technology.

“The interesting part is I get a lot of interest in concrete homes,” he says.

“The biggest thing that you have to overcome is finding a builder who is interested in doing something different.

Most builders are carpenters by trade.

That's what they know how to do. To build out of concrete is totally new to them and they're afraid of it. They don't understand it.”

The builder on this project is someone Purinton had worked with several times over the years.

The client chose the Thermomass system over insulated concrete forms (ICFs). Thermomass System CIP was used in the construction, with the Thermomass rigid insulation in the center of the cast-in-place walls.

Photo Credit: Thermomass

“I worked with the general contractor for four or five years previously to doing this project,” he says. “He's a very innovative guy. He's done many very energy-efficient houses and he's won some awards in energy efficiency. And he said, ‘I really believed everything you told me over the last few years, but there's always that little bit of doubt in my mind that what you were saying was 100% true.’ Now that he's built it and he’s actually been in the house, he absolutely understands what I was saying to him all along. He says, ‘I believed you, but I didn't.’”

Find a video walk-through of this project at ForConstructionPros. com/21342830.

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CONCRETE PAVEMENT

»

BY ARIELLE WINDHAM

Photo courtesy of Just Porciello, Conterra Restoration Ltd.

CHALLENGE:

Restore a Hotel’s Parking Garage, While Keeping it Open How one contractor found an eco-friendly solution for the removal of 200,000 sq. ft.

W

ith decades of experience in new construction and commercial renovation, general contractor and construction manager Arguson Projects Inc. understood the logistical challenges posed by a multiyear, multi-million dollar parking garage renovation in Toronto’s East End. The 39-year-old structure—an open-air parkade with a roof deck, two suspended slabs and asphalt on grade—needed to remain open while crews removed 200,000 sq. ft. of material from the second and third levels. Building tenants required parking to remain open, as well as continued access to the roof deck, which provided amenities for employees.

Seizing an opportunity to reduce not only the project’s carbon footprint, but also the overall cost, Arguson, in

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conjunction with the property owner, turned to Conterra Restoration and a suite of Aquajet hydrodemolition equipment for an eco-friendly solution.

PARKING PROBLEMS The suspended slabs within the parkade were heavily contaminated with chloride ions, or road salt, resulting in significant corrosion-related deterioration and cracking. The concrete needed significant repair/replacement to address structural integrity concerns and overall aesthetics of the suspended slabs. Working with RJC Engineers, a Canadian-based engineering firm specializing in parking facility design and restoration, Arguson determined hydrodemolition was the only concrete removal option that fit the unique needs of the project.

Part of the building sits on the roof deck, meaning vibrations needed to be eliminated wherever possible. The building is also home to a prep school with athletic facilities located just south of the parking structure, requiring both noise and dust control to minimize disruptions to students and faculty. A

nearby hotel also made nighttime noise an issue. The project managers needed a solution that would limit dust and other environmental impacts but was also quiet enough to proceed with the renovations during normal business hours.

“The main concerns for this project were noise and vibration generated by the construction activity, as well as the vast amount of concrete that needed to be removed to properly rehabilitate the suspended parking slabs,” says Philip Sarvinis, P.Eng., Managing Principal with RJC Engineers. “Hydrodemolition allowed the contractor to work through the day without disrupting building tenants or the neighboring properties, while at the same time removing large amounts of concrete. The process works extremely well with the added bonus that it doesn’t physically damage the remaining concrete left in place compared to traditional jackhammering operations.”

Arguson brought on Conterra Restoration, a Canadian-based contractor with extensive hydrodemolition experience. The company presented Arguson with a cutting-edge solution that not

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CONCRETE PAVEMENT CONTINUED only provided the productivity to meet deadlines, but also minimized impact on the tenants and environments. Conterra sourced an Aqua Cutter 710V—a hydrodemolition robot which could provide 25 times more productivity than a large crew using conventional equipment—supplied by Cor-Blast Services Inc. The 5,181-lbs. Aqua Cutter 710V uses a 14,500- to 40,000-psi water jet, which removes concrete by widening existing pores and micro cracks in the weakened structure. Since the process is impact-free, there are no vibrations, and therefore less risk of microfractures. Hydrodemolition also cleans and descales rebar without damaging it.

The plan also featured an Aquajet 700 Ecosilence high-pressure pump to provide ample power for the project—56 gpm at 18,700 psi. This would keep noise to a minimum, allowing crews to work during the day without

disturbing tenants.

“With the Ecosilence, the pump and diesel engine are inside a container with this machine, which dampens the sound enough you could run it under a window downtown and still be quieter than normal traffic,” says David Porciello, general manager for Conterra. “We paired a hoarding system with the Ecosilence to get down to 63dB at a range of 6 m.” Additionally, the Ecosilence allowed Conterra to work throughout the year, even at -4° F temepratures.

The contractor also included an EcoClear water treatment system as part of their tender. This unit provides on-site water treatment in real time for less than a penny per gallon. After passing through the EcoClear, wastewater can be released into the sanitary sewer system. With the project requiring in excess of 10 million gallons of water, this presented significant cost and carbon savings compared to alternatives,

such as trucking the wastewater out with vacuum trucks.

“Environmental stewardship has always been an important part of the conversation for us,” Porciello said. “With the Aquajet equipment we saw an opportunity to not only provide fast, highquality results, we could also drastically reduce our impact on the environment.

From eliminating the gas and exhaust of vac trucks to minimizing crews—and the associated emissions getting them to and from the worksite—we were able to present not only an economic solution, but an eco-friendly one as well.”

The company’s unique full-service approach to building restoration also gave them an advantage in the bidding process. In addition to hydrodemolition, Conterra bid subsequent phases of the project—including pouring new concrete, applying a waterproofing system and painting lines. Additionally, decades of experience, highly skilled

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crews, specialist subtrades, plus an outstanding record for satisfactory and ontime delivery made their bid stand out.

RECORD REMOVAL The project was broken into two phases over two years, commencing in December 2019. Conterra set up a staging area outside the parkade.

Depending on the day, the Aqua Cutter robot could be up to 615 ft. away and several stories above the pump system.

Arguson and Conterra have a dedicated crew of workers and subcontractors on-site with a small contingent running the Aqua Cutter and support equipment. The hydrodemolition removal process is monitored by one operator/technician with some assistance monitoring the EcoClear. Additionally, a team follows up behind the robot to remove the demolished concrete. Other crews are employed removing through-slabs,

JOB STATS Location: Toronto, Ontario, Canada Dates: Dec. 2019 – Spring 2022 (estimated) Duration: 2 years Material Removed: 200,000 sq. ft (estimated) Water Treated: 10 million gallons (estimated) Equipment: Aqua Cutter 710V, EcoClear, Ecosilence forming and other tasks throughout the site. For the most part, the robot removes concrete to a depth of 4 to 5 in.

“The Aqua Cutter finds what most engineers can’t—every millimeter of bad concrete,” Porciello says. “The robot can be programmed to remove a certain depth; however, the removal could be

deeper in certain areas if the strength of existing concrete is not adequate. This assures that all deteriorated concrete is removed and a sound substrate remains for superior bonding of the new concrete overlay. This gives us a clean slate of good concrete for stronger, longerlasting repairs.”

During an 8-hour shift, Conterra sees removal rates of 600 to 1,000 sq. ft. Had they opted for manual removal, Porciello estimates it would take a crew of 20—averaging 30 sq.ft. per person per day—to achieve the same productivity for removal only. Plus, the project would have been limited to overnight shifts to avoid noise disruptions for the building’s tenants.

Arielle Windham is a writer for the construction and demolition industry.

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BY JONATHAN KOZLOWSKI Brad Pict/AdobeStock

6 QUESTIONS ON SEALERS & POLISHABLE OVERLAYS What the finished floor will look like tends to be important to the floor owner.

Knowing the floor and your sealant will make all the difference.

G

reg Cabot is the digital marketing manager at Ameripolish, a manufacturer of concrete polishing products including dyes, colors, chemical abrasives, densifiers, maintenance products, and systems, as well as sealants. I sat down with him for a few questions on this penultimate layer of work to polished concrete floor. The last layer is maintenance, and we talk about that too.

Q

Why are there different types of sealers?

A. This is really a two- or threefold question. First, what kind of protection and what do you want it to look like when you’re done. One of the most important things to the building owner is what the finished product is going to look like. You can choose a matte finish, a satin finish, a glossy finish, or no change at all (meaning that the look of the finished floor will rely entirely on the diamond tooling). Work with your customer to match the environment

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the surface. That way you to a sustainable look. can get some trafFor example, if the fic on there. Once customer wants a topical starts to a glossy finish, wear, it’s time to but they have a reapply. It does super high trafa good job of fic environment protecting what’s and there are underneath it but spills all over the in a commercial or place—maybe it’s industrial environsomething like a ment—that’s not your machine shop where best bet. It’s going to they kind of work on An example of how wear out within a few forklifts. Most of these a semi-topical/semimonths. glossy sealers are toppenetrating sealer will look Some are going to ical or semi-topical at as a finished product. Notice perform better than best and would wear a slight haze in the shine. others.

For example, in quickly. In a high trafPhoto Credit: Ameripolish a stain resistance test fic environment where where you pour pickle juice or vinegar you want a glossy floor, I would recor something acidic on the surface ommend a fully penetrating sealer to see how long it takes for it to mar accompanied with the proper mainthe concrete, some sealers are going tenance to that floor. to last three or four hours, others 15 Also, know what the sealer will minutes. Others even longer than the do on the floor. Does it penetrate four-hour mark. It is really dependent the surface and protect the concrete on how much water and chemicals are from within? Does it penetrate a little in it. There’s not a one-size-fits-all. bit and sit on top to act as a sacriThis is why we usually say if ficial coating? Is it entirely a sacrifiyou’re going to be in a heavy trafcial coating? The fully penetrating fic spill environment you want to products tend to perform a lot better go with the fully penetrating just on stained and abrasion-resistant because—across the board, no matoverlays. Generally, Ameripolish recter the company—the fully penetratommends our penetrating sealers ing products do perform better with for high traffic environments or with stain resistance than the semi-tropifloors that are going to see a lot of cal or topical products. Because the use. For decorative finishes, with a lot topical nature of the product makes of different colors, we tend to sugthat sacrificial surface; it's designed gest a semi-penetrating / semi-topto literally be attacked by whatever ical sealant so that you can burnish the spill is so it protects the floor it. It has a glossy look and still has beneath it. That’s what it’s supposed somewhat of a sacrificial coating on

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to do. In terms of staining, it’s going to stain significantly easier because it’s actually just doing its job.

Q

What type of questions should contractors ask clients to find out which sealer to use?

A. Great question. Know what your maintenance program will look like. Do you have auto-scrubbers or is it just some mop and bucket situation? Do they have access to auto-scrubber machines? There are maintenance systems out there that can hold those floors up for years if the maintenance program is correct.

Ask what kind of traffic is going to happen. Is it subject to spilling?

It’s difficult to say because there are so many variables that go into it. But, really, the main thing is the maintenance program. If you are going to have a reliable maintenance

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program, you’re better off going with the fully penetrating sealer about 99.9% of the time. I reserve the semitopical ones for residential or office spaces that only see light traffic and maybe they have a little color on the floor. Topical sealers have a colorenhancing feature to them.

Q

How do you fix delaminating and flaking? Why do they happen?

A. You fix them by avoiding them. The flaking and delaminating issue is usually because the sealant product is too much of a topical base and it doesn’t breathe. Concrete is a porous and a breathing surface.

On a microscope, concrete looks like a sponge, and all these minerals, salts and moisture are actually being pushed out from the bottom of it as it continues to hydrate for the lifetime of the concrete.

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Imagine a piece of plastic on a hot cup of coffee. Where all that condensation builds up, all that moisture is trying to push out. If you trap that moisture with a coating, it builds up underneath and starts to bubble.

That’s where the delaminating and flaking comes from—eventually that sealer cracks and then it’s just going to start flaking off. You can avoid that by selecting a breathable sealer, designed for polished concrete.

If you do run into a situation where the product is already on the floor and it started to delaminate, it’s the unfortunate case that you have to remove it. There really is no Band-Aid for that situation.

Q

How do breathable sealants work?

A. Long story short, it lays on the pores of the concrete like a Teflon.

The sealer just covers the first couple of millimeters of the surface and once a breathable sealant dries, it doesn’t sit on the surface but in the entire pore structure beneath. As moisture and minerals work through, they can still push through the pour structure and get to the surface allowing some air space to breathe and get that moisture in and out.

Our penetrating sealer forms a hydrophobic barrier and an oleophobic barrier. When moisture moves up to where the sealer is, a breathable sealer allows that moisture out. When the moisture dries it should evaporate without issue; 85% or 90% of polished concrete floors that we see do not have these issues. In the other 10% where an efflorescence is left behind, it’s because the sealer is allowing it to breathe and be pushed to the surface.

If the sealer didn’t allow that, it would cause that flaking and delaminating.

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What’s happening in that 10%? How can we avoid efflorescence?

A. In a high-moisture scenario, the minerals that get pushed to the surface create efflorescence—a

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w b a c t l t s p t a s b

Q

m

m m s s c h

white dust on the surface—and that becomes an issue. We suggest to use a moisture vapor barrier and to do a calcium Chloride test to make sure that you don’t have a moisture problem in your slab. If you have a moisture problem, even with breathable sealants, that efflorescence could be present. A vapor barrier helps avoid that happening, but it’s not a guarantee. We suggest architects always specify a moisture vapor barrier because they can only help.

Q

What would be your advice to contractors designing a maintenance plan?

A. Work with both the manufacturer of the sealer and the manufacturer of the overlayment system. Try to get them in the same room at the same time. The chemical manufacturer is going to have one recommendation and the

overlayment company is going to have theirs because they know what reacts well with their product. We recommend that our contractors hand over some sort of maintenance packet to the floor owner, like, “here’s the floor I installed, this is the maintenance program that goes with it.” If the floor owner follows it, the floor shouldn’t fail.

The contractor has to know what works for their floors. Because like I mentioned with the semi-topical products, there’s a maintenance program for it that works well enough but it is going to require a sealer reapplication. For example, a school where reapplication would be on an annual basis in the entryways.

There you’re seeing thousands of kids walk through the door but that front area will wear out first because the dirt on your shoes is like an equivalent to a 200-grit resin tool.

It’s just tearing the floor apart just from dirty shoes and it’s going to dull your floor out. That’s when the contractor has to come in, clean up the area, reseal the product, burnish it, pop it out, and feather it in to match the rest of the floor.

In the end, read your concrete.

Every slab of concrete is different, even if they are right next to each other. It may be the last thing you apply to the slab, but the sealant on top of a polished concrete floor requires continued attention and that means the right maintenance plan. “The sealer needs to walk hand in hand with the maintenance program,” says Cabot. “If you don’t maintain it properly, it will never work no matter what. Something is going to go astray. The floor is not going to look like you want it if it’s not being maintained properly.”

WHICH VACUUM IS BEST FOR YOUR JOBSITE? Find out at edcoinc.com/vac-selection/

We Got You! E-Vac 176 Part# EDM103576

edcostore.com •

Vortex Vac 200 Part# ED33125HCONK

800-638-3326• sales@edcostore.com • edcoinc.com

www.ForConstructionPros.com/Concrete

CONC0421_42-45_PCQA.indd 45

Bagger Vac 200 Part# ED33125HCONDB

APRIL/MAY 2021

CONCRETE CONTRACTOR 45

4/7/21 10:49 AM

SPECIFICATION GUIDE: SCREEDS Curb Roller Batt Screed 6000

SCREEDS

Curb Roller Eel Screed 6100

Curb Roller Hydra-Screed HS3000

The technical information you need for a smooth, flat surface.

Blade Lengths

Handles

Engine/Motor & HP

Fuel Tank Capacity

Curb Roller Manufacturing, Batt Screed 6000

3-22 ft.

3 Position Folding Handle

60 V Lithium Ion FLEXVOLT Battery

1,800-2,500 sq. ft. (estimated)

ForConstructionPros.com/21062140

Curb Roller Manufacturing, Eel Screed 6100

3-22 ft.

3 Position Folding Handle

Any 120 V, 60 hz Outlet or Generator

Unlimited

ForConstructionPros.com/21136234

ForConstructionPros.com/21062138

HAND

HAND & SPIN

Model

Weight

Curb Roller Manufacturing, Hydra-Screed HS3000

100 lbs. (approx., w/o pipe)

up to 30 ft. (using 6-in.

OD pipe)

3 Position Folding Handle

Hydraulically Driven (3-5 GPM at 2,250 PSI Required)

Unlimited

MARSHALLTOWN, Ezyscreed™

2.9-7.9 lbs.

3-12 ft.

One

N/A

N/A

CHAPIN 1999 COMPRESSOR CHARGED SPRAYER You rely on our industry leading concrete sprayers to get the job done. Now make your work even easier with the Chapin 1999 compressor charged sprayer! The 1999 features a pressure fitting for air supply, a 3.5 gallon Tri-Poxy coated tank, and a wide mouth opening for easy filling. The brass wand allows you to spray easily and consistently with Shut-off and Lock-on features, and a brass fan-tip nozzle.

Height

2 in.

Width

1.625 in.

More Information

ForConstructionPros.com/12003790

CHAPIN 21172XP ACETONE SPRAYER The Chapin 21127XP Acetone Sprayer is the ideal sprayer for decorative concrete jobs, specifically designed for staining with acetonebased dyes and other acetone only applications.

The 3 gallon translucent tank has a wide mouth opening for easy filling.

The Dripless trigger grip shut-off and brass wand with lock-off feature prevent accidental discharge.

WWW.CHAPINMFG.COM | 1-800-950-4458 46 CONCRETE CONTRACTOR

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APRIL/MAY 2021

www.ForConstructionPros.com/Concrete

4/7/21 10:55 AM

MARSHALLTOWN Spin Screed Battery Operated Screed

MARSHALLTOWN Ezyscreed

MARSHALLTOWN Spin Screed Corded Screed Allen® Engineering Corp., SE12 - Engine-driven Truss Screed

0

Weight

Blade Lengths

Handles

Engine/Motor & HP

MARSHALLTOWN, Battery Operated Spin Screed

Less than 100 lbs. (with 22-ft. pipe)

Pipe lengths up to 22 ft.

THandles

Makita Right Angle Drill, 36 V

5 ft.

ForConstructionPros.com/21134340

MARSHALLTOWN, Corded Spin Screed

Less than 100 lbs. (with 22-ft. pipe)

Pipe lengths up to 22 ft.

THandles

Makita Right Angle Drill, 10 amp

5 ft.

ForConstructionPros.com/21330880

End handles

Honda GX270 (for widths <50 in.), Honda GX340 (for widths >50 in.), 270 cc, 9 hp / 11 hp

POWER

Model

Allen® Engineering Corp., SE12 Razorback™ Truss Screed

HAND & SPIN

POWER (ROLLER)

Allen® Engineering Corp., SA12 - Air-driven Truss Screed

Allen® Engineering Corp., SA12 Air-driven Truss Screed

37 lbs., 46 lbs., 90 lbs., 135 lbs., 180 lbs.

2 ft., 2.5 ft., 5 ft,.

7.5 ft., 10 ft.

End handles

Fuel Tank Capacity

Height

Width

More Information

5.3 liters

65 ft. (max)

ForConstructionPros.com/12057760

N/A

65 ft. (max)

ForConstructionPros.com/21330894

Introducing for 2021, The TPC Guidance Controlled Slipform Concrete Paver The TPC is operated via a Radio Controlled Belly Pack instrument box. In auto mode, the machine will follow the guidance string and adjust tracking and screed elevation automatically. The screed comes in different widths from 48” to 96”. The TPC eliminates the need for forms. Just grade and set the string line!

Standard Features • The conveyor can be moved to feed the machine from either side.

• The hopper has an auger inside to be sure the material fills both sides of the hopper.

• The hopper has two hydraulic cylinders which raise the hopper and screed for transport and easy loading on the trailer.

• The 74 HP Hatz German engine is EPA compliant in all 50 states and delivers plenty of power.

• This engine, coupled with a proclaim pump, will give the hydraulic power needed year after year.

• This is a machine designed with only the basics needed to slipform the walk or pad with no forms required. By designing the TPC this way, we were able to cut the cost and make it affordable for everyone, not just the big guys.

MADE IN THE U.S.A.

www.ForConstructionPros.com/Concrete

CONC0421_46-49_SpecGuide_dh.indd 47

105 School House Road Cheshire, CT 06410, 800-872-5726, 203-271-1682

www.salsco.com APRIL/MAY 2021

CONCRETE CONTRACTOR 47

4/7/21 10:55 AM

SPECIFICATION GUIDE: SCREEDS

POWER SCREED

POWER

WET

Allen® Engineering HD7070 - Magic Screed

Metal Forms Corp., Speed Screed® Cruiser™

Metal Forms Corp., Speed Screed® Roller™

Ligchine, SCREEDSAVER ELITE

Model

Weight

Blade Lengths

Handles

Engine/Motor & HP

Fuel Tank Capacity

Height

Width

More Information

Allen® Engineering Corp., HD7070 Magic Screed

30 lbs.

4 ft., 6 ft., 8 ft., 10 ft., 12 ft., 14 ft., 16 ft.

Adjustable

Honda GX35, 35.8 cc, 1.5 hp

0.63 liters

N/A

16 ft. (max)

ForConstructionPros.com/12057778

Metal Forms Corp., Speed Screed® Cruiser™

11 lbs. per foot

60 ft. (max)

Built-in lift handles

Honda, 8 hp

13 in.

14 in.

ForConstructionPros.com/12189180

Metal Forms Corp., Speed Screed® Roller™

200 lbs. per foot

30 ft. (max)

Honda, 22 hp

12 gal.

46 in.

54 in.

ForConstructionPros.com/21331067

Ligchine, SCREEDSAVER ELITE

6,540 lbs.

12 ft.

Kubota V1505, 4 Cylinder

12 gal.

5 ft., 5 in.

5 ft., 9 inc.

ForConstructionPros.com/21195235

Ligchine, SPIDERSCREED

1,280 lbs.

10-ft. screed head

Honda GX360, 20.8 hp

5 gal.

57 in.

94 in.

ForConstructionPros.com/21083055

INDEX ADVERTISER ................... PAGE

Indoor Booth

Outdoor Booth

48 CONCRETE CONTRACTOR

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Allen Engineering ......................................... 5, 48 Blastcrete Equipment Co ................................. 37 Brokk Inc. ........................................................... 13 Chapin Mfg Inc ........................................... 17, 46 Curb Roller Mfg. LLC ........................................ 24 Cuts Inc. ............................................................... 7 EDCO Equipment Development Co. ............. 45 GCP Applied Technologies ............................. 11 Gomaco ............................................................ 23 Graco, Inc. ......................................................... 31 Kipper Crete LLC. ............................................. 12 Ligchine International Corp. .............................. 9 Magic Screed .................................................... 39 Max USA Corp .................................................. 41 MB America, Inc................................................ 29 Miller Formless.................................................. 40 Minnich Manufacturing .................................... 15 Oztec Industries Inc. ........................................... 2 Quikrete............................................................. 27 SafeBasements Inc. .......................................... 40 Sakrete of North America ................................ 21 Salsco Inc. .......................................................... 47 Simpson Strong-Tie Co., Inc. ........................... 51 Somero Enterprises .......................................... 49 Strong Manufacturing ...................................... 44 Superabrasive Inc ............................................. 43 Tekla Structures ................................................. 19 Vanguard ADA Systems ................................... 28 W.R. Meadows, Inc. .......................................... 25 White Cap Supply Holdings, LLC .................... 52 Wirtgen America Inc......................................... 33

www.ForConstructionPros.com/Concrete

4/7/21 10:56 AM

The Compact Boom Laser Screed® Machine has been

PERFECTED

Introducing the

Laser Screed® Machine

• Safer/Better Visibility - No lower frame and straightforward, 360° design gives greater visibility.

• Easier to Operate - Head lowering with hydraulic cylinder, no wrenches required.

• More Maneuverable - Steering with 2-wheel, 4-wheel, and crab-style.

• Smoother Process - Somero® signature Soft Landing feature.

®

• Lighter Weight - Our lightest weight boom screed – ever!

Come see this and our other signature Laser Screed® Machines at World of Concrete 2021 - BOOTH W2125.

WWW.SOMERO.COM or call 239.210.6519

Get it Done. Get a Somero.® CONC0421_46-49_SpecGuide_dh.indd 49

4/7/21 10:56 AM

THE LAST PLACEMENT

»

BY BRAD HUMPHREY

You Just Gotta Love ‘Em! It's important for those of us in ownership and leadership to stand back and just appreciate the workers involved in the day-to-day jobsite grind.

I

had a simple but great reminder of how much I appreciate the construction worker in the field plugging away, every day, at his or her craft. Nothing fancy here; just raw, transparent, and hardly “PC” people who really want nothing more than to make a living, work with people they respect and like (most of the time), and be thought of as a good person who can be counted on.

In this current environment where we are “employee challenged,” (i.e. we are more than one million workers short of what our industry needs) most contractors are realizing that the people they have working for them today might not necessarily be there tomorrow. While an owner would like to believe that all of his employees are loyal and would never leave, the fact is a growing number of contractors need little encouragement to pursue “pirating away” other contractor’s workers for a few dollars more an hour.

I want to refresh your perspective to reconnect with your workers. Take a look again at the primary reasons that your company is still in business.

Consider that many of our hourly workers are responsible wage earners, just looking to find a way to raise their kids, maybe buy a new fishing rod and reel occasionally, take their spouse out for dinner on a Friday night, and take their family on a little vacation. Oh, and don’t forget, most of these same workers dream of assisting their kids to attend college or to some post-high school institution. Most of our people comply with what we ask them to do; they don’t always like it but they do it anyway.

The sense of humor of some of our workers is stuff you can’t script.

It wouldn’t make for material for a standup comedian but, captured in the

50 CONCRETE CONTRACTOR

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right context, it can bring you to your knees. Having one of your guys get stuck in the jobsite “Porta-Potty” can get the entire crew laughing. “Crapper Bob” will live with this nickname for the remainder of his career.

As funny as some of our workers can be, we also are blessed to have many employees who are brilliant—those with natural smarts that allow them to solve some for the most complex issues of the day. Like the foreman who, challenged with how to get around an unsafe area in the ground, actually developed a better and safer, approach.

Another observation is the ease at which the crew guys can make an outsider feel welcome. As owners, leaders and even this ol’ consultant know, it is easy to forget that for many construction workers, their crew mates represent just about the closest thing to a family or some close-knit fraternity that they have ever known. It is within this construction “priesthood” that workers share their joys, hurts, pains and hopes.

Within this environment they provide and receive counseling. With all the pressures to find great workers, and to retain them, it is still the construction workers who you now employ that will have the most influence with new workers. Whether the new worker stays or leaves after two days is almost always dependent on the way in which your current workers treat them.

Perhaps one of the best things I like about construction workers is how so many of them will sacrifice their own personal time to help someone else.

Listening in on a conversation between two crew workers, one of them thanked the other for having spent all day Saturday helping him finish painting his basement the past weekend.

I realize that a few of our workers

can be a royal pain in the you-knowwhat sometimes. But, how many more workers are really productive and actually pretty fun to hang out with during the day? Yes, we need to set our expectations and goals consistently and yes, we need to ensure that we’re getting the right work completed the right way the first time. But past that, isn’t it just as important for those of us in ownership and leadership to stand back and just appreciate the workers who are dealing with the consequences of government compliance mandates, extreme weather conditions, over-zealous inspectors, and not always great running equipment?

Do yourself a favor. Try spending some extra time with your workers over the next few weeks. Just hang. Don’t try to dominate the conversation. Let the conversations develop and let them come to you. Reflect on your workers’ sense of humor, their humanity at times when few others will extend the same, and their efforts to present a positive image of your company when you’re not around.

Tell your workers just how much you appreciate them and their contribution.

Sure, hold them accountable, but add a bit of recognition and appreciation for the individuals working for you. God knows we’re having a hard time finding and keeping good workers.

Observe. Reflect and appreciate.

Brad Humphrey’s podcast, The Contractor’s Best Friend, sponsored by AC Business Media and Caterpillar, continues to be one of the favorites of suppliers and contractors alike. As Vice President of Pavecon Ltd., Brad continues to develop, teach, write, and share his 35-plus years of industry knowledge.

For articles, podcasts and more, visit ForConstructionPros. com/10116722.

www.ForConstructionPros.com/Concrete

4/7/21 10:58 AM

Help falling walls stand tall.

Introducing Heli-Tie™ helical wall and stitching ties from Simpson Strong-Tie. Our helical wall tie stabilizes damaged masonry walls by anchoring the facade to structural members, while the helical stitching tie repairs cracks. Both stainless-steel ties install quickly and easily, providing an expansion-free, inconspicuous repair that preserves the appearance of the building — allowing you to avoid rebuilding or unsightly fixes. And with our jobsite load testing, follow-up evaluation and widespread product availability, you’ll maximize the effectiveness of your repair and regain the stability of your walls. ®

For more on how Simpson Strong-Tie Heli-Tie helical wall and stitching ties can help you easily and quickly restore your damaged walls, visit go.strongtie.com/helitie or call (800) 999-5099. © 2021 Simpson

CONC0421_50-52_LastPlace.indd 51

Strong-Tie Company Inc. HELITIE21C

4/8/21 8:49 AM

CONC0421_50-52_LastPlace.indd 52

4/8/21 8:56 AM