Concrete Contractor January 2022

January 2022

THE LEADING TRADE MAGAZINE IN THE CONCRETE INDUSTRY

DESIGNING OUTSIDE THE

CONCRETE BOX

Are You VIBRATING YOUR CONCRETE Too Much?

Quantifying a Sustainability Benefit of CONCRETE PAVEMENT

The story behind repurposing a 90year old a concrete building in Houston

➜ Inside the PCA CARBON NEUTRALITY ROADMAP

How to Control Unsightly

WALL CRACKS

YOUR GUIDE TO WORLD OF CONCRETE 2022 WWW.FORCONSTRUCTIONPROS.COM/CONCRETE

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What To See, When & The Booths To Check Out 1/3/22 9:32 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.

www.minnich-mfg.com

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om

WHAT’S INSIDE

JANUARY 2022 | Issue 1, Volume 22

COVER STORY 24 Designing Outside the Concrete Box A Houston concrete structure, now repurposed, sees new life as technology innovation hub for the community.

DEPARTMENTS 4 Editor’s Letter 22 New Products 30 Product Focus

Tools & Light Equipment

40 Specification Guide Forms

41 Specification Guide Compact Construction Equipment

42 The Last Placement

Cover Photo Credit: G. Lyon Photography

FEATURES 6

The Concrete Contractor Guide to World of Concrete 2022

36 Q&A on Carbon

Neutrality

We spoke with Rick Bohan, VP of Sustainability for the Portland Cement Association, about their Roadmap to Carbon Neutrality.

Use these few pages to help find your way through the show.

14 ACI Inspection Programs Improving quality in concrete construction.

18 The History of the Internal Concrete Vibrator & The Rise of the Controlled Frequency Design Over the last 60 years, concrete vibrators have evolved into a necessary machine for concrete jobs.

38 Carbonation: Quantifying a Sustainabilty Benefit of Concrete Pavement Most of concrete’s carbon emissions are associated with manufacturing portland cement, but there is another, less-talkedabout way: carbonation.

Before selecting the technique, be sure to clearly establish the objectives of the crack repair.

34 3 Release Mistakes You Must Avoid Using the wrong form of release, not using a conditional release and using the wrong through date are all avoidable mistakes when using releases in construction.

WHAT’S ONLINE

ForConstructionPros.com/21940164

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14 How to Control Unsightly Wall Cracks

FORM YOUR BUSINESS

Top 20 Changes in Laws, Regulations That Can Put Your Construction Business at Risk

www.ForConstructionPros.com/Concrete

HOW TO

3 Threats to Profitability Due to Construction Equipment Breakdowns Avoid paying the price.

ForConstructionPros.com/21784624

JANUARY 2022

CONCRETE CONTRACTOR 3

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EDITOR’S LETTER

Welcome to

2022 T

Published by AC Business Media

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

www.ForConstructionPros.com/Concrete PUBLICATION STAFF

Editor Contributing Writers

his issue marks a little over a year of my heading up the editor position with Concrete Contractor. My time included a few notable moments, conversations on some interesting concepts, the development of a few ideas, and some great discussions with some great people. This issue also marks, in a strange turn of events, my second JONATHAN KOZLOWSKI, EDITOR World of Concrete. I figured this would be an JKOZLOWSKI@ opportune time to reflect on that June 2021 event.

ACBUSINESSMEDIA.COM Let's address the one thing most comments pointed at, it was warm outside back then. Thankfully my job allowed me to walk inside to escape the temperature. Sure, it could have been warmer (Las Vegas is a desert after all), but everyone made due and worked with the shade. We had a little fun on social media with a series looking for the "coolest thing" at the show. While we saw some great stuff back then, I'm excited for this year's show as it looks like we'll get hands-on with quite a few innovative concepts. Find out some of the things you'll find at and during the show in our guide to World of Concrete this issue, page 6.

Where not exclusive to WOC, the concrete contractor and concrete construction community have been some of the friendliest people I have had the pleasure to meet. I was lucky enough to attend a few seminars when I could—even one of the training sessions from our longtime contributing expert and advisory board member, Kim Basham (who is speaking again this year). He writes a great "how to" on foundational cracks this issue, page 14.

Here's to the new year. Here's to another World of Concrete. Here's to you, constant reader; may your concrete ne'er crack and your jobs run on track.

As always, stay safe out there.

Senior Production Manager Art Director Audience Development Manager ADVERTISING SALES (800) 538-5544

FORCONSTRUCTIONPROS.COM

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

Chief Executive Officer Chief Financial Officer Chief Digital Officer Chief Revenue Officer VP Audience Development Director, Demand Generation & Education Vice President, Operations Group Content Director

Advisory Board Kim Basham KB Engineering Cheyenne, Wyo.

Jim Cuviello Cuviello Concrete Polished | Stained | Crafted Stevensville, Md.

James Baty II Concrete Foundations Association Mt. Vernon, Iowa

Chris Klemaske T.B. Penick & Sons, Inc. San Diego, Calif.

4 CONCRETE CONTRACTOR

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Jim Bagan Nick Raether Jon Minnick

CONCRETE CONTRACTOR (USPS 021-799, ISSN 1935-1887 (print); ISSN 2471-2302 (online) is published 6 times a year: January, February/March, April-June (Spring), July-September (Summer), 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 JANUARY 2022, Issue 1, Volume 22 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.

LinkedIn.com/company/ Concrete-Contractor-Magazine

Dennis Purinton Purinton Builders, Inc. East Granby, Conn.

Ron Spink JoAnn Breuchel Kris Heineman Amy Schwandt Ronda Hughes

Published and copyrighted 2022 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.

Working on a creative new project? Interested in writing a “how to” piece? Have a story you would like to share?

Email me at jkozlowski@acbusinessmedia.com Twitter.com/ ConcreteInsider

Wayne Grayson wgrayson@ACBusinessMedia.com Larry Stewart lstewart@ACBusinessMedia.com

Editor-in-Chief

Share Your Expertise

Facebook.com/ ConcreteContractor

jsison@ACBusinessMedia.com nlawson@ACBusinessMedia.com sdunphy@ACBusinessMedia.com tsoma@ACBusinessMedia.com

Jon Sison Nikki Lawson Sean Dunphy Tadashi Soma

CALLING CONCRETE CONTRACTORS…

Instagram.com/ ConcreteContractor

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

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

®

www.ForConstructionPros.com/Concrete

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Finisher Specialty Commercial/Industrial Technician Strength Testing Technician Laboratory Testing Technician Aggregate Testing Technician Aggregate/Soils Base Technician Concrete Construction Construction Special Inspector Concrete Quality Technical Manager Concrete Transportation Special Inspector Tilt-Up Supervisor Tilt-Up Technician Shotcrete Nozzleman Shotcrete Nozzlemanin-Training Masonry Field Testing Technician Masonry Laboratory Testing Technician Adhesive Anchor Installer Field Testing Technician Flatwork Finisher Specialty Commercial/Industrial Finisher Specialty Commercial/Industrial Technician Strength Testing Technician Laboratory Testing Technician Aggregate Testing Technician Aggregate/Soils Base Technician Concrete Construction Special Inspector Field Testing Concrete Quality Technical Manager Concrete Transportation Special Inspector Tilt-Up Supervisor Tilt-Up Technician Shotcrete Nozzleman Shotcrete Nozzleman-in-Training Masonry ch tyFlatwork Finisher nician Masonry Laboratory Testing Technicia Adhesive Anchor Installer Field Testing Technician Flatwork Finisher Specialty Commercial/Industrial Finisher Specialty Commercial/Industrial Technician Strength Testing Technician Laboratory Testing Technician Aggregate Testing Technician Aggregate/Soils Base Technician Concrete Construction Special Inspector Base Technician Transportation Special Inspector Concrete Transportation Special Inspector Tilt-Up Supervisor Tilt-Up Technician Shotcrete Nozzleman Shotcrete Nozzleman-in-Training Masonry Field Testing Technician Masonry Laboratory Testing Technicia Adhesive Anchor Installer Field Testing Technician Flatwork isher Shotcrete her Commercial/Industrial Finisher Specialty Commercial/Industrial Technician Strength TesNozzlemanian Laboratory Testing Technician Aggregate Testing Technician Tilt-Up Soils Base Technician Concrete Construction Special Inspector Associate Concrete TransSupervisor ial Inspector Concrete Transportation Special Inspector Tilt-Up Supervisor Tilt-Up Technician Shotcrete Nozzleman Shotcrete Nozzleman-in-Training Masonry Field Testing Technician Masonry Laboratory Testing Technician FF vvv Adhesive Anchor Installer Field Testing Technician Flatwork ty Strength Specialty ialtyCommercial/IndustrialFinisherSpecialtyCommercial/IndustrialTechnicianStrengthTestingTechnician Concrete Testing Technician Aggregate Testing Technician Aggregate/Soils Base Technician ete Construction Special Inspector Concrete Quality Technical Manager Concrete nician Special Special Inspector Tilt-Up Supervisor Tilt-Up Technician Shotcrete Nozzleman Field Testing otcrete Inspector an-in-Training Masonry Field Testing Technician Masonry Laboratory TTesting Technician The American Concrete Institute offers nearlyCommercial/Industrial Adhesive Anchor Installer Field Testing Technician Flatwork Finisher Specialty 30 certification programs to satisfy any Finisher Specialty Commercial/Industrial Technician Strength Testing Technician Laboratory Testing l Tilt-Up Aggregate Testing Technician Aggregate/Soils Base Technician Concrete Construction number of concrete specialties.

Learn how to ecial Technicianssociate Concrete Transportation Inspector Concrete Transportation get your team ACISpecial certified at Special Inspector Tilt-Up Supervisor Tilt-Up Technician Shotcrete Nozzleman ShotAdhesive Anchor concrete.org/certification. in-Training Masonry Field Testing Technician Masonry Laboratory Testing Technicia Installer Anchor Technician Flatwork echnician Flatwork Finisher Specialty Commercial/Industrial Finisher Specialty Aggregate Testingtrial Technician Strength Testing Technician Laboratory Testing TechnicianTechni Testing Technician Aggregate/Soils Base Technician Concrete Construction Special Inspector Concrete Quality Technical Manager Concrete Transportation Special Inspector Tilt-Up Supervisor Tilt-Up Technician Shotcrete Nozzleman Shotcrete Nozzleman-in-Training Masonry Field Testing Technician Masonry Laboratory Testing Technician Adhesive Anchor Installer Field Testing Technician Flatwork Finisher Specialty Commercial/Industrial Adhesive Anchor Installer Industrial cian Strength Testing Technician Laboratory Testing Technician Aggregate Testing Technician Con Aggregate/Soils Base Technician Concrete Construction Special Inspector Concrete Quality T Inspector Tilt-Up SupervisorTransportation Special Inspector Shotcrete Nozzleman-in-TrainingShotcrete Nozzleman Tilt-Up Technician Shotcrete Nozzleman-in-Training Masonry Field Testing Technician Adhesive Anchor Installer Masonry Laboratory Testing Technician Field Testing Technician Flatwork

WIN MORE PROJECTS WITH ACI CERTIFICATION

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The Concrete Contractor Guide to World of Concrete

2022

AC Business Media

A

fter restarting the world with live events in June 2021, World of Concrete has finally returned to January. Use these few pages to help find your way through the show.

TECHNICIAN CERTIFICATION & CFA WINTER MEETING In 2021, the Concrete Foundations Association has reintroduced members to the practice of leadership networking. New resources include virtual Best Practice Groups that meet monthly as well as the formation of in-person CEO Peer Groups for select members looking for deeper commitments. The ACI/

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CFA Residential Foundation Technician Certification takes place on Thursday and the annual Winter Meeting hosted at The Strat on Wednesday night.

Concrete companies are invited to become part of this professional construction network of leading businesses dedicated to setting, maintaining, and promoting the highest standards of ethical conduct and professional behavior to advance the industry. The CFA maintains and encourages open, constructive conversations for all members of the Association.

Come by and visit W2719 to find out how you can become involved.

WIN $22,000 IN CREDIT Miller Formless will be showcasing several in-demand products near the WOC Education area. Featured equipment includes the M-1000, the CG-200, and the M-6040—the most versatile, productive slipform paving machine in the company’s product line.

Miller Formless is sponsoring a sweepstakes with incredible giveaways, including a $22,000 credit towards a new M-series machine in 2022. Winners will be announced at the show, details are available at millerformless.com.

Find Miller Formless at booth W741.

www.ForConstructionPros.com/Concrete

12/28/21 9:15 AM

CONCRETE COMBAT On Thursday at 10:30am, Sakrete will hold the final challenge of competition series Concrete Combat–LIVE in the booth. This will be a full-scale video production featuring the biggest challenge yet. Filmed for release after WOC. If you want to find out who wins before anyone else, you’ve got to be there! We'll have seating, refreshments and some custom swag for everyone who signs up early on Sakrete.com/woc. Sakrete also has eight demos throughout Tuesday and Wednesday on all things concrete!

Find Sakrete at booth C4450.

AC Business Media

TAKE A SPIN WITH A ROLLER SCREED Curb Roller Manufacturing is showcasing its first modular screed system, the patent-pending Lynx Screed.

This versatile alternative to completing flatwork provides a series of linkable screed pipes to accommodate concrete pours in varying widths from 3-22 ft.

Unlike traditional roller screeds, the Lynx modular system removes the need for purchasing dedicated pipe lengths to offer easy adaptability for a multitude of pours. Its aluminum design decreases strenuous setup, shipping costs, and transportation requirements for jobs that call for longer pipes.

Curb Roller Manufacturing will be featuring the Lynx Screed at booth D420.

SLAB SOLUTIONS & A NEW BUGGY Allen Engineering will be featuring its AW16-B buggy and accepting orders for 2022 on MP and MSP riders. Powered

by Vanguard’s 48 V Li-Ion power pack capable of 8-9 hour run times, the Allen AW16-B fully electric battery-powered buggy has been uniquely designed and tested for jobsites and projects where emissions are a major concern.

Allen Engineerign are also one of the sponsors of and will also be speaking at the "Quality in Concrete Slab Luncheon & Forum" on Wednesday, 11:30-1:30.

See show planner for the location of the luncheon. Find Allen Engineering at booths D836 & W2230.

RECHARGING THE CONCRETE INDUSTRY Hilti Group have announced its latest innovation providing concrete contractors with a fully-connected experience like never before. Nuron is a powerful 22V cordless battery platform featuring s/tate-of-the-art technologies with a new protective housing made of reinforced fiberglass with shock-absorbing bumpers.

Nuron launches with the capability of powering more than 70 Hilti tools from light-duty drilling to heavy-duty concrete breaking—even applications that were once restricted to corded, gas-powered or higher voltage battery systems.

Find the new Nuron battery and other concrete innovations from Hilti at booths D1245 & N1837.

The Euclid Chemical Company

AC Business Media

www.ForConstructionPros.com/Concrete

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WORLD OF CONCRETE 2022 GUIDE GOING ONCE …

Wednesday’s 2022 Concrete Industry Management auction features items ranging Allen Engineering from equipment, vacation packages, computers, TVs, and more. Among these, a 2022 Mack Granite truck was donated by Mack Trucks and equipped with a McNeilus FLEX Controls Standard Mixer by McNeilus.

Proceeds benefit the CIM National Steering Committee and support the current CIM programs at Middle Tennessee State University, New Jersey Institute of Technology, Texas State University, California State UniversityChico, South Dakota State University, the Executive MBA program, as well as help fund scholarships.

CIM’s booth is W106.

DOES THAT CONCRETE HAVE REBAR IN IT? WHERE? For contractors, knowing a rebar’s position (including depth) in existing concrete can be vital for drilling or confirming that the rebars are even there in the first place. Where detection can be a challenge, there are a few methods in accomplishing the task. One is utilizing ground-penetrating radar (GPR). GSSI is offering extensive in-person and online training programs on using grand-penetrating radar equipment safely and effectively in the field. Not only does the company have four training classes during WOC, but 100+ in-person classes are scheduled—and that’s only till June 2022.

For more information on GSSI, visit booth W1417.

A CHEMICAL REACTION Euclid Chemical will participate in the following sessions throughout the week: • Wednesday—Luncheon forum on LOOKING FOR A CONCRETE the prevention of surface defects CONTRACTOR COMFORTABLE on slabs, such as variations in ON SOCIAL MEDIA thickness, excess moisture, Have you been told that and high sulfate soils. your attention to detail Euclid also donated a on a jobsite is strong? concrete sealer and Maybe you find yourwebinar training self constantly taking package for the progress photos and CIM auction. videos of your work, • Thursday— while talking about Luncheon panel the tools you find most discussion on the value useful to get the job done. of a good distribution MAX USA Corp. is lookHilti partner, as well as various ing to see the professionals out there concrete industry best practices for making an impact in the world of conconstruction distributors. struction, and is proud to showcase their Educational seminar hosted by Amir safety tips, tricks of the trade, but most Bonakdar, Euclid’s Senior Director importantly, their work! of Business Development-North If you think you have what it takes America, and Brent Coulson, District to be a superinfluencer for MAX USA Manager-Northern Calif./Nevada, Corp., stop by the booth at W3705. on ideal design and construction practices for fiber-reinforced concrete.

Seminar’s room yet to be determined. Find Euclid Chemical at booth C4226.

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ATTENTION FELLOW MEMBERS The American Society of Concrete Contractors (ASCC) has a full schedule of events, meetings, and a kickoff bash. Don't miss the presentation of the Terry Fricks Floor Excellence Awards—a panel of four industry professionals judged submitted projects based on layout, F-number floor run map and data for overall project, type and layout of reinforcement, curl, aesthetics, percentage of grinding and number of placements requiring grinding, and safety.

• Sunday— 2:30-3:30, The Manufacturer's Advisory Council board meeting • Monday— 12-2, Concrete Polishing Council board meeting; 2-4, Decorative Concrete Council board meeting; 5-6, ASCC Annual meeting 6-9, Kickoff Bash in Ballroom C, D, E, F, and G (advanced registration required) • Tuesday— 9-10:30, Paving Committee meeting; 10-11:30, Emerging Leaders Committee meeting; 11:15-1, ASCC Education, Research & Development Foundation meeting; 11:30-1:30, Polishing Luncheon; 1-4, SRMC Board meeting • Wednesday— 10:30-12, Constructability Committee meeting; 10:30-2, Annual Conference Committee meeting, Ballroom D; Find ASCC at booth C4505 and DCC/CPC at O30718. Meeting rooms are yet to be determined. All ballroom and pavilion events are at the Westgate hotel.

www.ForConstructionPros.com/Concrete

12/28/21 9:15 AM

W

Xtreme Curb and Gutter Machines Visit with us about your 2022 project needs!

West Hall -- W2725

info@gomaco.com ❘ www.gomaco.com Long, straight runs are nice. But many of you have curb and gutter projects with short runs, radii, and corners in parking lots or tight locations. GOMACO’s Xtreme curb and gutter machines have Zero-Turn capabilities for maneuverability. You’ll be able to place more curb than ever before, move your machine in ways you have never moved before, and be able to pour a tight radius that you could only dream of before.

We will have our full line of Xtreme curb and gutter machines on display in the GOMACO booth at World of Concrete 2022. Stop by and see one in person and visit with GOMACO’s concrete slipform paving specialists about your upcoming project needs.

CONCRETE STREETS AND HIGHWAYS ❘ AIRPORT RUNWAYS ❘ CURB AND GUTTER ❘ SIDEWALKS RECREATIONAL TRAILS ❘ SAFETY BARRIER ❘ BRIDGE PARAPET ❘ BRIDGE DECKS ❘ IRRIGATION CANALS GOMACO CORPORATION IN IDA GROVE, IOWA, USA ❘ 712-364-3347

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WORLD OF CONCRETE 2022 GUIDE CO2 & TOMORROW’S MIX PLANTS Where the contractor’s main attention maybe at the site—in the mud, if you will—discovering the latest advancements for the concrete plant can help understand how tomorrow’s concrete is changing. Astec and its brands RexCon, CON-E-CO and BMH Systems, have now united under the Astec brand while retaining their legacy in the product names.

At the booth, learn more about Astec’s comprehensive line of products for concrete production through a display that includes full-size plants, detailed scale models and an interactive virtual experience. Products featured include the RexCon Mobile 12 and CON-E-CO LO-PRO Transit Mix Plants, a RexCon tilt mixer, and a BMH Rollmaster horizontal reversing mixer.

While there, learn more about the strategic partnership with CarbonCure

Technologies whose products enable concrete producers to reduce their carbon footprint without sacrificing its quality and strength. CarbonCure injects CO2 in the batching process resulting in a high-performing concrete while utilizing less cement. The exciting partnership is a step forward for Astec as the company strengthens its commitment to sustainability by allowing us to offer our customers sustainable building solutions. Visit the booth to see how CarbonCure Technologies easily integrates with our concrete plants to reduce embodied carbon at the front of a project’s lifecycle.

Find Astec at booth N737.

SWITCH SPEEDS IN YOUR CONCRETE VIBRATOR Minnich Manufacturing is highlighting its Control Speed Vibrator (CSV) - a lightweight, durable, electric flex shaft concrete vibrator controlled through

Minnich Manufacturing

Bluetooth and the Minnich app.

Using an iOS or Android device, operators can choose between set speeds of 6,000, 8,000, 10,500 and open VPM. Choosing slower vibration speeds lessens material separation and reduces surface blemishes and repairs. Once a speed is chosen, the CSV will maintain that speed as the concrete load changes. The 15-amp universal motor drives a full line of Minnich shafts and heads and comes standard with a quick disconnect that adapts to the vibrators of many manufacturers. The CSV has been designed with a soft start that saves energy and mechanical wear on the motor and power system.

Stop by booth W2224 as Minnich unveils their newest product with a special video and product display.

BETTER MACHINES

AMS-MERLO.COM 10 CONCRETE CONTRACTOR

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(803) 327 - 4949 info@appliedmach.com

Booth W-1250

www.ForConstructionPros.com/Concrete

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ing

.

Sakrete

MIX DESIGN & TESTING LABS Learn more about mix design and testing labs with speakers GCP Regional Technical Services Manager Tom Greene and Technical Services Manager at Monarch Cement Co., Joe Hug, with hands-on training. A two-part seminar is scheduled for Tuesday, 10-1:30 and 1-4:30.

The first-half training session will consist of two lab stations: 1) Materials & Mix Design and 2) Field Quality Control. Participants will learn about the identification and examination of common materials used in concrete, and watch tabletop demonstrations showing how admixtures work. Be prepared to mix a small batch of concrete yourself.

The afternoon half focuses on the proper methodologies for testing concrete in the field. Watch a demonstration of tools and participate in a lab to address slump, density, air content by pressure meter, air content by volumetric meter,

temperature, and specimen casting.

Participants will also learn about testing tolerances, significance of fresh concrete tests and how testing contributes to the quality control of the project.

See show planner for location.

REDUCING NOISE ONE MACHINE AT A TIME Finding efficient, cost-effective ways to limit sound pollution has become a major priority. But sound-proofing an active jobsite is easier said than done.

Incorporating sound abatement techniques can reduce decibels, but there is no way to completely eliminate the biggest onsite noise polluters—machines.

Contractors have begun looking to innovative manufacturers for creative equipment solutions to stem the noise.

Aquajet is highlighting their Ecosilence 3.0 and other hydrodemolition innovations. The Ecosilence 3.0 reduces noise and allows

for a more compact jobsite, while enhancing environmental stewardship and lowering overall operating costs.

Features include integrated auto start/ stop tech to save as much as 6.6 gallons of fuel a day, capable of being run in urban areas with strict noise restrictions, and provides plenty of power to operate renovation and road and bridge repair.

Find Aquajet co-located with Brokk at booth W1305.

OUR KIND OF PLAYGROUND

This is the natural habitat for Brokk’s compact giants.

With the perfect combination of power, operability and accessibility our demolition robots provide efficient solutions to increase profits.

See us at booth W1305

Brokk Inc. | Monroe, WA | 1-360-794-1277 | info@brokkinc.com | www.brokk.com

www.ForConstructionPros.com/Concrete

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WORLD OF CONCRETE 2022 GUIDE Merlo (AMS)

Merlo (AMS) is showcasing its telehandlers at booth W1250.

GET A TROWEL SHINE The Lavina line, manufactured by Superabrasive, has the widest range of equipment and tools for floor grinding and polishing and is known for its reliability, versatility, and ease of use. For large-scale industrial projects, Superabrasive offers a fast and cost-effective system for polishing with power trowels, called Trowel Shine, compatible with almost any trowel. Superabrasive is adding two new Lavina Elite Power Trowels, both feature an integrated wheelset and a crank system for changing tools, a heavy-duty shroud, a transport wheel and other user-friendly features.

• LP30E—An electric trowel with a 61-in. (1,555 mm) work path, that gets through standard doors. Great productivity in a small package.

• LP36GE— Propane-driven, powered by Kohler Propane engine (Command Pro EFI PCV740) for more uptime, better fuel efficiency, and performance. It has an 80-in. (2,032 mm) work path with 8 x 13-in. free spinning tool holders and updated manual steering.

See the new models at booth C5413.

Miller Formless

NEW MINI CEMENT MIXER Merlo telehandlers on display include the compact material handling dynamo: P27.6 Plus with a 6,000 lbs. maximum load capacity and lift of 19 ft. 4 in.; the heavy-duty telehandlers with independent front stabilizers, load capacities up to 11,000 lbs., and lift up to 59 ft. 4 in.; and the Roto. An operator’s dream machine, with independent stabilizers, 360-degree rotating turret, and 20-degree tilt cab. Maximum load capacities up to 15,400 lbs. Lift heights up to 115 ft. All Merlo telehandlers deliver spacious cabs with 360-degree views, Heat/AC, comfortable seating, intuitive, easy to access controls and advanced safety systems. Plus, no-flex booms handle numerous attachments.

Introducing the Merlo DBM 3500 self-contained Mini Cement Mixer.

Carries its own water; has an automatic load shovel; Drum volume: 6.5 cu./yd., Yield: 4.6 cu./yd. Two direction travel; ground controls; rotating drum pivots 180 degrees on a fifth wheel delivering a 330-degree radius pour around the machine.

THE FUEL THAT CONTRACTORS RUN ON For Milwaukee Tool’s first year attending World of Concrete, the company will be featuring its groundbreaking cordless MX FUEL Equipment System—revolutionizing the light equipmetn market. MX FUEL delivers the performance, run-time, and durability demanded by the trades without the hazards associated with emissions, noise, vibration, and the frustrations of gas maintenance.

Find Milwaukee Tools in booth O30800.

FAST CURING & INDUSTRIAL GRADE COATING Pecora-Deck HB1000 is a fast curing, low odor industrial grade coating that allows high mil (up to 125) applications without the issues typically associated with off gassing. HB1000 provides an aesthetically appealing surface while protecting traffic and non-traffic bearing substrates from physical abuse, water infiltration and UV degradation.

HB1000 may be applied over PecoraDeck 802 or 802 FC elastomeric base coats when a waterproofing system is required.

Find Pecora at booths C4018 & O30619.

YOUR EQUIPMENT MANAGEMENT SOLUTION Struggling with seeing and managing your mixed fleet of assets as they are spread across multiple projects and locations? Tenna’s construction technology platform is designed to make your equipment fleet management simple and allows you to fully manage your assets anywhere from the field, trailer or main office. Tenna lets you stay connected to your assets so you can focus on the work you need to do that is key to your business.

Find how tracking technology can help your business at booth N2377.

Superabrasive

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www.ForConstructionPros.com/Concrete

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HOW TO

»

BY KIM BASHAM, PHD PE FACI

How To Control Unsightly

WALL CRACKS 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.

Kim Basham

C

oncrete volume changes due to changes in moisture and temperature. As concrete dries, it shrinks. Length change related to drying shrinkage for unreinforced concrete can range up to 0.08% whereas normal reinforced concrete is about 0.02% to 0.03% due to the internal restraint associated with the reinforcing.[1] For an unreinforced or lightly reinforced 100 ft. wall, drying shrinkage tries to shorten the wall up to about one inch. If the wall is normally reinforced, shortening is reduced to about 1/4 to 3/8 of an inch. With regards to thermal contraction, our 100 ft. wall subjected to a 50º F temperature drop tries to shorten an additional 5/8 of an inch.

As illustrated in figure 1 (page 16), wall shortening from concrete drying shrinkage and/or thermal cooling combined with restraints including wall corners, intersecting walls, and foundations with dowel bars causes vertical cracks to form. Due to shrinkage and restraints that resist wall shortening, tensile stresses form, and when stresses exceed the tensile capacity of the concrete, cracking occurs.

Another way of thinking about this shrinkage and restraint behavior is to place our 100 ft. wall in outer space.

Floating in space without restraints, the wall could freely shrink or shorten to a new length without cracking.

Back on earth with wall restraints, cracks form and relieve the tensile

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stresses created by the concrete shrinkage. If wall stresses are not sufficiently relieved by cracking, new cracks occur between previously formed cracks. As illustrated in figure 1, most wall cracks start at the bottom and grow upwards due to the rigid restraint created by the foundation.

The risk of wall cracking can be reduced by minimizing the root causes.

Reducing the water content of the concrete and/or including a shrinkage reducing admixture can help reduce the risk of cracking or at least the severity of cracking. Concrete shrinkage is strongly dependent on the total water content of the concrete. So, reducing the water content reduces concrete drying shrinkage and the risk of vertical wall cracks.

If wall cracks are a concern, discuss concrete mix options to reduce drying shrinkage with your concrete supplier.

Most likely, it will not be possible to reduce wall restraints and concrete temperature variations. For this reason, contraction joints and horizontal reinforcing are the best options to control random vertical cracks. Of course, the designer is responsible for establishing the mix design requirements in addition

Concrete Shrinkage + Restraints = Tensile Stresses = Wall Cracks

to specifying either contraction joints or horizontal reinforcing or both and the related details.

CONTRACTION JOINTS Installing contraction joints is an economical and simple way to control the location of vertical cracks. Contraction joints are weakened planes created by reducing wall thicknesses, reinforcing, or both so cracking occurs within the joints. As concrete dries and tensile stresses increase, cracks occur at the thinner sections within the contraction joints.

Contraction joints are made using wooden, rubber, plastic, or metal strips attached to the inside form faces as illustrated in figure 2 (page 17). Strips create narrow vertical grooves on both sides of the wall creating thinner wall sections. The total depth of the two grooves should be at least 1/4 of the wall thickness to ensure the thinner section is sufficiently weakened to control the location of cracks.

Wall 6 in.

Thickness

8 in.

10 in.

A

1 in.

1 ¼ in.

1 ¾ in.*

B

½ in.

½ in.

½ in.

C

¾ in.

¾ in.

¾ in.

*May conflict with horizontal rebar if wall has two mats In general, recommended joint spacing is the height of the wall for walls taller than about 12 ft. and three times the wall height for walls less than about 8 ft.[2] Due to wall restraints associated with corners and intersecting walls, install joints within 10-15 ft. of wall corners and intersections. These recommendations recognize that the upper portion of the wall is likely to cool and shrink faster than the lower portion that is more restrained. Both conditions

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HOW TO CONTINUED Figure 1. Typical vertical wall cracking if no joints are provided.

Also, reentry corner cracks can form due to stress concentrations at interior corners that can contribute to vertical wall cracking.

create tensile stresses within walls that create vertical cracks. Consider placing joints at abrupt wall changes, in line with openings to help control reentry corner cracks, and in locations to create an acceptable visual appearance. Each wall should be evaluated to determine the best joint locations and spacings.

Exterior grooves can be sealed with a non-sag, elastomeric sealant (e.g., polyurethanes and silicones) to prevent penetration of cold air, moisture, water, and insects through cracks. Sealants can also be used in interior grooves to conceal cracks.

Reinforcement Horizontal wall reinforcing controls the width of shrinkage cracks—not the location. How tightly cracks are held together depends on the amount and spacing of the reinforcing. Increasing the amount or reducing the spacing of reinforcing passing through cracks, decreases crack widths. In many cases, this is the designer’s choice to control vertical wall cracks. With this design choice, don’t expect a crack-free wall.

Expect random cracking to occur but crack widths should be limited by the amount of wall (horizontal) reinforcing.

Using both load and building code requirements, designers establish the required reinforcing for walls. Horizontal reinforcing may be determined by load conditions, minimum code

requirements to ensure structural integrity, or minimum “temperature and shrinkage” reinforcing as specified by building codes or the local building officials.

The amount of horizontal reinforcing can be quantified by computing the reinforcing percentage that is based on the reinforcing and wall thickness.

For example, #4 at 12 in. on center located in the middle of an 8-in. thick wall yields a reinforcing percentage of 0.21%.[3] While 0.21% exceeds the minimum 0.18% temperature and shrinkage reinforcing specified by the International Building Code, it may not hold the vertical wall cracks sufficiently tight to satisfy the wall’s function or the owner’s expectations.

If our example wall was 23 ft. long with 0.21% horizontal reinforcing, approximate crack widths exceeding about 0.010 inches should be expected.

To limit cracks widths to about 0.010 in. and 0.004 in. (watertight), reinforcing percentages would need to be increased to approximately 0.30% and 0.55%, respectively.[4] To achieve a

0.30% value, the reinforcing would need to be #4@8 in. on center and for 0.55%, #5 at 7 in. or #6 at 10 in. on center, respectively.

As explained with this simple wall example, significant amounts of horizontal reinforcing are required to keep vertical crack widths narrow. For watertight retaining walls, the minimum wall thickness is typically 10 in. with two mats of reinforcing with significant amounts of horizontal reinforcing to keep crack widths less than 0.004 in.

Designers commonly increase the amount of horizontal reinforcing in the lower 3 to 5 ft. of walls to help control the width of cracks that start at the bottom and grow upwards.

Contraction Joints & Reinforcement Contraction joints and reinforcing can be combined to control vertical cracking but if too much reinforcing crosses joints, joints may not be sufficiently weakened to activate and control the cracking location. Recommendations for reinforcing at contraction joints range from stopping all reinforcing 2-3 in. from the joint, allowing 50% or another amount of the reinforcing to continue through the joint, and

A crack compactor card can help you determine the width of the crack in question. Place the card on the crack and align the line that matches the crack width.

Kim Basham

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discontinuing all reinforcement and installing slip dowels to maintain alignment of the adjacent wall surfaces.

CRACK REPAIR OPTIONS Reducing concrete shrinkage and wall restraints and installing contraction joints with or without horizontal reinforcement does not ensure that random or out-of-joint cracks will not occur. If out-of-joint cracking does occur, there are several repair options that can be used to either seal or structurally repair cracks if needed.

• Route and Seal. The simplest and most economical means to repair vertical cracks regardless of crack widths. It is a nonstructural repair that consists of routing or enlarging the crack to create a V-shaped sealant reservoir and then filling the reservoir with a non-sag, elastomeric sealant (e.g., polyurethanes and silicones).

• Polyurethane Injection. Inject wet or leaky cracks with polyurethane resins that combine with water to form an expanding and flexible gel to choke off leaks and seal cracks. This technique is a full-depth and lasting crack repair.

• Epoxy Injection. Welds or bonds crack faces together and restores the soundness and integrity of the concrete. However, if the injected

Figure 2. Details for forming contraction joints in walls.

cracks are active (still opening due to continued concrete shrinkage or acting as joints to relieve thermal stresses) new cracks may form adjacent to the repaired cracks.

THERE’S A THIRD OPTION This article has presented two proven crack control options for walls. Unfortunately, a third crack control option is often used: let it crack. This approach assumes you will deal with cracks after they occur. This choice can become time-consuming and expensive if any party misinterprets the cracks as defective concrete or workmanship that jeopardizes the structural integrity, function, or service life of the structure. It is better to be proactive and consider crack control options and crack expectations before starting the job.

Kim Basham is president of KB Engineering, LLC which provides engineering services to the concrete industry and a registered professional engineer in 19 states. Dr. Basham also teaches seminars and workshops dealing with all aspects of concrete including concrete technology, concrete construction, and troubleshooting for the American Concrete Institute, World of

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CONC0122_14-17_Howto.indd 17

Concrete, and other concrete/construction organizations. He can be reached at KBasham@KBEngLLC.com.

Find this article at ForConstructionPros.com/ 21952625.

REFERENCES

1. Kosmatka, S. H. and Wilson, M. L., Design and Control of Concrete Mixtures, 5th Edition, 2011, pp. 180, Portland Cement Association, www.cement.org 2. ACI 224.3R-95 Joints in Concrete Construction, p. 32, American Concrete Institute, www. concrete.org; 3. [(0.20 in2/ft)/(8 in. x 12 in.)] x 100 = 0.21% 4. Kianoush, M. R., Acaran, M., and Dullerud, E., Cracking in Liquid-Containing Structures, Selecting the appropriate temperature and shrinkage reinforcement, Concrete International, pp. 62 – 66, April 2006, American Concrete Institute, www.concrete.org

JANUARY 2022

CONCRETE CONTRACTOR 17

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BY MICHAEL MORRISON, JOHN NEHASIL

ACI Inspection Programs: Improving Quality in Concrete Construction

A

key area of certification that can improve the quality of completed projects is the certification of inspectors. Inspector certification programs focus on proper procedures for inspecting various concrete installations and construction practices and identify inspectors capable of recognizing issues that require attention during each phase of a concrete construction project. To develop inspector programs, American Concrete Institute (ACI) committees reference codes, standards, and other documents with which an inspector should be familiar and establish a set of specific inspection responsibilities reflected in each program’s Job Task Analysis. The committees also establish certification requirements, including minimum work experience, and develop examination questions and passing score criteria. The following is a look at concrete inspection certifications available through ACI. In 2019, ACI launched its PostInstalled Concrete Anchor Installation Inspector (PICAA) certification program. This program modified the ACI Adhesive Anchor Installation Inspector (AAII) certification program (available since 2016), expanding it to include inspection of post-installed mechanical anchors and concrete screws.

The original Adhesive Anchor Installation Inspector program was launched following the Adhesive Anchor Installer program that was developed in response to a 2006 incident in a Boston interstate highway tunnel, where collapse of ceiling panels crushed a car and killed a passenger. In addition to other issues, the installation of adhesive bolt fixtures supporting the ceiling panels was implicated

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calling for construction inspectors may in the failure, calling attention to a gap be wide-ranging, so ACI’s inspector in the quality chain. Industry experts program is designed to include tasks realized that effective adhesive anchor pertaining to quality control (where installation relies on both the installer the inspector is employed by the conunderstanding and executing proper tractor), code compliance (where the procedures, and inspectors possessing the specialized knowledge of and beyond inspector is employed by a governmental enforcement agency) and owner that of the installers. acceptance (where the inspector acts on While the immediate need was to behalf of the project owner). address adhesive anchor installation The Concrete Construction Speinspection, ACI realized during the cial Inspector program assessdevelopment of the AAII es knowledge of how to program that projects Adobe Stock Images By anut21ng Stock inspect and record the could also benefit results of concrete from the inspection construction inspecof post-installed tion based on codes mechanical and job specificaanchors. Not tions. The program wishing to delay covers inspection the availability of during preplacethe AAII program, ment, placement, and ACI delayed incorpost-placement operaporating inspection of tions. Certified Concrete mechanical anchors into Construction Special Inspectors are the program until after the AAII identified as able to read plans, evaluprogram became available. ate concrete conveyance, placement, The expanded PICAA program consolidation, testing procedures, and covers all of the AAII program materiinspect reinforcement placement. Speals and also covers the installation of cial inspectors can help determine if post-installed mechanical anchors. (Cerweather or other site conditions necestification candidates are now directed sitate special concreting operations and to the PICAA program for concrete can perform post-placement inspection anchor inspection certification. The original AAII program no longer admits of curing concrete.

An Associate Concrete Construcparticipants.) tion Special Inspector qualification Both the new Post-Installed Concrete is also available. These associates have Anchor Installation Inspector program passed the written and plans reading and the existing Adhesive Anchor Instalexamination and are knowledgelation Inspector program are cited in able about inspection procedures the new ACI 318-19: Building Codes for concrete construction, including Requirements for Structural Concrete preplacement, placement, and postand Commentary, released in June 2019. placement operations, but do not have The number of real-world scenarios

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ACI INSPECTION PROGRAMS CONTINUED the experience required to qualify as an ACI Concrete Construction Special Inspector.

ACI’s Concrete Transportation Construction Inspector program covers knowledge specific to the construction of concrete transportation projects, including preplacement, placement, and post-placement operations. Candidates are tested in plan reading, soil-cement, piling installations, formwork installation and removal, reinforcements, embedments, sampling and testing freshly mixed concrete, conveying, placing, consolidation, finishing, jointing, curing, and protection.

Candidates may also be designated as Concrete Transportation Construction Inspectors-in-Training. These individuals have demonstrated knowledge in concrete inspection methods for transportation projects by passing the written and plans reading examinations, but do not have the experience

required to qualify as an ACI Concrete Transportation Construction Inspector.

Associate Concrete Construction Special Inspector and Concrete Transportation Construction Inspector-in-Training certifications are available to persons possessing ACI Field Testing Technician – Grade I certification.

Concrete Construction Special Inspector and Concrete Transportation Construction Inspector certifications are available to persons possessing ACI Concrete Field Testing Technician – Grade I certification and who meet requirements for education and/or work experience.

Persons whose ACI Concrete Field Testing certification has expired may be eligible to certify as inspectors if they pass the current ACI Concrete Field Testing Technician—Grade I written exam within one year of passing the Inspector exam. To complete an inspector program and achieve certification, participants must obtain a passing grade

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on a written examination as well as a plans-reading examination.

Introduced in 2020, the Nondestructive Testing program identifies specialists who understand and have the skill to use the tools and test methods associated with determining the in-place strength of concrete. In addition to being used to investigate existing conditions in a concrete structure, nondestructive tests are used to ensure that specifications are being met during construction.

The goal of the program is to promote consistency throughout the industry, with all personnel adhering to ASTM standards including those governing pulse velocity through concrete, penetration resistance of hardened concrete, rebound number of hardened concrete, compressive strength of concrete cylinders cast in place in cylindrical molds, pull-out strength of hardened concrete, and the estimating concrete strength by maturity method.

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Program participants typically use their own equipment to conduct performance evaluations that are required as part of the course, so the skills proven during examination are applicable to the real-world conditions the candidate will encounter on the job.

With the use of shotcrete increasing in many construction projects, ACI introduced its Shotcrete Inspection program in 2020.

Inspectors of shotcreting operations must understand the responsibilities and qualification requirements of the nozzleman as well as the inspection requirements as cited in the documents governing the construction of the project. Topics covered include: • Safety guidelines • Hot- and cold-weather concreting • Fiber-reinforced shotcrete • Shotcrete specifications • Standard practice for preparing and testing specimens from shotcrete test

panels • Standard test method for obtaining and testing drilled cores of shotcrete • Visual core quality evaluation, and • Other relevant evaluation methods The program is open to persons who hold a ACI Field Testing Technician – Grade I certification and who meet requirements for education and/ or work experience. (Persons whose ACI Concrete Field-Testing certification has expired may be eligible to certify as inspectors if they pass the current ACI Concrete Field Testing Technician— Grade I written exam within one year of passing the Inspector exam.) Satisfactory work experience must include at least one of the following: testing, inspection, and quality control of shotcrete; supervision of shotcrete construction work; and design of shotcrete structures. Verification of the amount and range of work experience by the applicant's employer(s) is required.

All ACI inspector certifications are valid for five years from the date of successful completion of requirements. As with other ACI certification programs, inspector programs are offered through ACI Chapter and Non-Chapter Sponsoring Groups who offer the programs within their communities. By identifying qualified individuals responsible for inspecting concrete, ACI inspector programs add another level of quality assurance to the construction environment.

Michael Morrison is the manager of program development at the American Concrete Institute.

John W. Nehasil is the managing director of certification at the American Concrete Institute.

For more by the ACI, visit ForConstructionPros.com/ 10071932.

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CONCRETE CONTRACTOR 21

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NEW PRODUCTS

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NEW PRODUCTS FOR THE CONCRETE CONTRACTOR

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Contractors report that WearCOAT 440FS is easy to apply evenly and consistently. Most importantly, the high-grade formula has proven superior in allowing them to take on projects through winter months when higher humidity and cooler concrete substrates can yield this unwelcome problem.

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12/28/21 9:27 AM

COVER STORY

»

BY RACHEL CALAFELL

Designing Outside the CONCRETE

BOX

R

epurposing existing structures, especially those made of concrete, has proven popular of late as a means to cost-effectively develop creative space, shorten construction schedules, and reduce the impact on the environment. While the former two are well-known strategies, the latter typically involves the reduction of embodied carbon. Emissions associated with extracting and installing new materials are reduced as well as the amount of waste produced during demolition.

In 2017, Rice Management Company, stewards of the Rice

University endowment, purchased the remaining years of a 99-year lease for a former Sears department store in Houston’s Midtown. The goal was to repurpose the existing structure into a collaborative technology innovation hub for Houston’s entrepreneurial, corporate, and academic communities. The repurposed structure would be known as The Ion. However, repurposing the standalone “concrete box” while maintaining its original character presented numerous engineering challenges. “The original building was a dark box,” says

Dennis Wittry, managing principal at Walter P Moore. “To make the building inviting to commercial tenants, bringing daylight into the space was critical.

The original scope of work anticipated using punched windows to bring in nominal daylight into the space while minimizing demolition of the exterior concrete walls that were serving as the primarily lateral system for the building.”

The final solution involved a more significant extent of demolition both on the building exterior and interior.

Constructed in 1939, with

G. Lyon Photography

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additional modifications complete in the 1960s, the three-story concrete building was not structurally designed for expansion. During the proposal phase, Rice Management Company decided to proceed with the steel-framed vertical expansion of two stories as well as a horizontal expansion of the existing concrete structure on the lower three levels.

ADAPTIVE REUSE The design intent to repurpose the building was to strengthen or adapt the structures in ways that made it look like it was part of the original construction.

Therefore, the horizontal and vertical expansions would serve different roles once the building was repurposed. The horizontal concrete-related expansion was a completion of the historic original structure. New openings in the existing structure were framed out by creating new concrete beams within the existing slab, rather than introducing new steel beams. This created an uncluttered look that complemented the original structure.

“Conceptually and practically, the horizontal expansion made most design sense in concrete, the system of the original structure,” says Anneli Rice, project director at SHoP Architects.

As for the two-story vertical expansion of the structure, the use of steel framing minimized the increase in load on the existing structure. To support the added load required strengthening of the existing spread footing foundations.

However, the existing columns did not require strengthening. Walter P Moore worked with a geotechnical engineer to determine that the existing soil was adequate to support a higher pressure than the foundations were originally designed.

“This limited the need to expand the spread footings, but required their strengthening,” Wittry says. “To

Rice Management hired Walter P Moore as the structural engineer of record, three design and architectural firms— James Carpenter Design Associates, SHoP Architects, and Gensler—while Gilbane served as the general contractor and Encore Concrete Construction was the concrete contractor.

strengthen the spread footings, the space between the top of footing and top of basement level slab on grade was utilized.

We drilled and epoxied dowels into the existing top of footing to compositely connect it to a new thickened section.”

Meanwhile, the framing for the existing roof at the third level did not have sufficient load capacity to serve as an occupied floor. As a result, new steel overbuild framing was spanned between the existing columns. The new framing did not require fireproofing due to the existing concrete roof slab directly below.

In order to introduce daylight into the structure, multi-story openings were cut into the concrete walls for a new curtainwall. Furthermore, a stunning 26 by 92-ft. light well was constructed in the center of the structure. Designed

by James Carpenter Design Associates, the light well makes the adaptation of the large floorplates into workspaces possible, providing critical access to daylight and the outdoors.

“We wanted the center of the building to come alive with light and activity, and this central volume created a canvas for these spaces to connect to the sky,” says Joseph Welker, studio director at James Carpenter Design Associates.

To create the light well, four concrete columns were demolished in the middle of the structure as well as a large

G. Lyon Photography

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COVER STORY CONTINUED G. Lyon Photography

area of three existing concrete slabs.

The light well cut an angled slice out of the building to follow the path of reflected light from a skylight above.

However, it also left a cantilevering concrete slab condition of varying lengths at each level.

“To avoid cracking of the existing slabs, they were ‘overcut’ to the column edge to allow distribution of reinforcement based on the new support conditions,” Wittry says. “A construction sequence was developed for the construction of the light well to avoid

overloading existing elements.”

The remaining concrete slabs were hung at each level via threeinch diameter hanger rods from new concrete transfer girders that were poured over the existing roof within the depth of the steel overbuild. The original plan was to extend the hanger rods to the new roof and support them from the steel.

However, Walter P Moore designed them to stop at the existing roof level, which freed the two new upper floors from visual obstructions in the light well.

STRUCTURAL CONCRETE Rice Management Company preferred to keep the existing concrete structural components as well as the retrofitted structural concrete exposed throughout the building as part of The Ion’s design. This included all columns and floor framing.

Each retrofitted area in The Ion includes existing exposed 9.5-in. concrete flat slab structure with 4.5-in. drop panels at each column. Walter P Moore’s structural design widened existing concrete beams or cast new 4.5-in. deep beam stems doweled into the soffit of the existing slab where existing openings needed to be infilled or existing beams strengthened. By matching the depth of these beams to the existing drop panels, the beams appear as part of the original construction.

Due to the extensive new openings for curtain wall in the exterior concrete walls and the additional wind exposure due to the two-story vertical expansion, new concrete shear walls were introduced at the concrete floors of the building near the stair and elevator cores. Steel braced frames were used

G. Lyon Photography

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COVER STORY CONTINUED G. Lyon Photography

over top of the concrete shear walls, at the vertically expanded floor levels.

The beams and shear walls were constructed using self-consolidating concrete pumped through new holes created in the existing slabs.

“Self-consolidating concrete was used in the concrete beams that were added to the existing structure as well as in the new shear walls,” says Aaron Smith, project manager at Encore Concrete Construction. “In an existing structure, when placing new concrete beams underneath an existing floor plate, standard concrete with a 5-in. slump could not be placed from above.

Self-consolidating concrete was used as a means to ensure quality.”

To pour the self-consolidating concrete, large core holes were placed roughly 10 ft. apart through the existing slab and it was poured from the top.

Smaller holes approximately 0.5 in. in diameter were drilled approximately 2 ft. apart between the larger holes so air could escape and not become trapped between the new self-consolidating concrete and the existing slab and beams.

the open interior to the surrounding streetscape. Large, multistory exterior openings were added for new windows in the concrete walls, as well as the twostory vertical expansion.

The Ion was designed to maintain the aesthetic of the northwest and northeast storefront corners, while vertically extending the curtainwall in the corners by 15 ft. It was a challenge to the building team to achieve this while concurrently maintaining the stability of the areas, which supported the existing concrete façade and concrete roof framing.

“Maintaining the storefront aesthetic was extremely difficult from a construction standpoint,” says Taliah McGowan, senior project manager at Gilbane Building Company. “To install the curtainwall and maintain the corner aesthetic, the existing concrete walls needed to be demolished and opened up.”

This required the existing concrete structure to be reinforced with a new steel structure, but the reshoring required to carry the existing roof beams—weighing upwards of 100,000 lbs. that were previously supported by the concrete to be demolished— impeded the placement of the new structure, according to McGowan.

Shoring was installed in the center portion of the wall so the outer locations could be demolished. Once this was complete, a portion of the

new steel framing was installed to support the wall. After the center shoring was removed, the remainder of the demolition and steel installation occurred.

FINAL TRANSFORMATION During the transformation from a stand-alone department store into a collaborative innovation technology hub, The Ion presented the entire building team with a series of structuraland concrete-related challenges.

Repurposing of the 1939 concrete structure involved demolition of existing stairs, escalator, center columns and floor slab, and cutting new openings in the exterior walls and floor slabs for new stairs and elevators, while infilling existing stair and elevator openings.

Transforming the original department store in lieu of its complete demolition and new build minimized embodied carbon, provided a platform for innovative design and engineering, and created a truly unique space to inspire “outside the concrete box” innovations for many years to come.

Rachel Calafell, PE, is a principal and project manager at Walter P Moore. She can be reached at rcalafell@walterpmoore.com.

Find this article at ForConstructionPros.com/ 21940606.

EXTERIOR UPGRADES The Ion seamlessly integrated the original art deco style of the structure, particularly at the ground-level storefront façade on the north side. The addition of the glass curtainwall on the building’s south end, and introduction of daylight through large openings in the east and west concrete exterior walls connect G. Lyon Photography

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PRODUCTS

TOOLS & LIGHT EQUIPMENT

Max USA's PowerLite HN120 Pneumatic Concrete/Steel Pinner

Makinex Lift Assist

The Makinex Lift Assist is a simple, easy to install attachment for 60-90-lb. pneumatic hammers. The ergonomically designed Lift Assist reduces operator stress and fatigue, resulting in higher productivity.

• Pushes and lifts 350 lbs. of force—not only lifting the weight of the hammer, but also releasing the buried chisel from the ground and allowing each of the 1,200+ blows to have a smooth exit and transition to continue the cut or demo.

• Its "foot" extends out of the bottom to lift up the tool and enable easy repositioning of the bit before breaking material again • Designed to reduce operator stress and fatigue, improve efficiency and productivity, and reduce risk of jackhammerrelated back injuries • Weighs just 9 lbs., is quick and easy to assemble to any 90-lb. pneumatic jackhammer, and shares the tool's existing air supply ForConstructionPros.com/21497132

Valtec's VP614 OmniPoly Poly Trowel Blade

Designed to control dark burnish marks on new concrete floor installation, Valtec Group LLC's VP614 OmniPoly Poly Trowel Blades (patent-pending) are now available in a 6 by 14-in. size for 36-in. rotors for walk-behind and ride-on power trowels.

• A rigid main body for producing a hard and uniform finish • Its flush bottom surface eliminates voids that collect fines that could later cause scratches • Made from non-rusting materials make it easy to clean, handle, and store • The long-lasting abrasion-resistant material reduces blade changes • Operator friendly and low noise for highperformance use • Cost per SF is better than steel making it valuable as an everyday blade ForConstructionPros.com/21521215

The PowerLite HN120 concrete/steel pinner can shoot one pin per second unlike P.A.T.’s which require operators to either load a single pin and powder load one at a time to fire each shot or load a maximum of 10 pins along with powder loads.

Traveling back and forth between your work area and the place where you keep the pins and powder reduces productivity.

The difference in reloading time when using PowerLite tools saves operators time and time is money.

• Magazine holds 50 pins and shoots pins from 1 to 2 1/2 in. long • Attachment parts available for wood to concrete, drywall to concrete, and wood to steel applications • Eliminates the need for gas or powder • Durable metal housing ForConstructionPros.com/10083928

Simpson Strong Tie's RCA-C Rigid Connector Angle

The Steele Mixer by Steele House Industries is manually-powered, weighs 34 lbs., and can mix a 60-lb bag of concrete ready-to-pour in less than 45 seconds.

Water and dry materials are poured into the pivoting mixing drum. Rocking the drum from side to side via the wooden handles incorporates the materials thoroughly and can produce ready-to-pour concrete faster than an electric mixer. It can make a wide variety of cement-based concretes and mortars including ordinary concrete, masonry mortar, stucco, deck mud, fat mud, self-leveling underlayment, and other water-mixed materials, up to a 90-lb bag of premixed dry material at a time.

Due to the drum’s design, mixing performance is thorough and highly efficient, so it can produce structurally sound concrete using the specified quantity of water. It also eliminates the temptation to add extra water, protecting the final strength of the concrete. In third-party testing, a commercial premixed bag of concrete produced in the Steele Mixer exceeded the specified 4,000 psi compressive strength in less than 28 days.

The Steele Mixer, built from wood, steel, and 100% recycled low-density polyethylene (LDPE) is light enough to be used in remote locations that remain inaccessible for electric mixers. It can be picked up and carried, full of concrete, and taken to the pour, and is also compact enough to operate inside a small residential bathroom. Its size, portability, and affordability make it an ideal tool for general contractors, plasterers, tilesetters, masonry, landscapers, fencing contractors, farmers, ranchers, and DIY homeowners.

Steele House partnered with Habitat for Humanity, donating one mixer for every 100 units sold.

Simpson Strong-Tie's RCA-C rigid connector angle is an ideal solution for attaching cold-formed steel (CFS) stud framing to concrete supports.

• 2 by 2-in. legs for plenty of room to make attachments to structure and stud framing • Multiple screw pattern options for different load rating options on stud framing • Prepunched holes for attachment of screws to stud framing and concrete • A range of load applications—the connector can be used either to form a heavy-duty shear and tension connector or to form a light-duty moment connection Designed to save installers time and reduce the cost of drilling connector holes at the jobsite, the RCA-C provides the most anchor options available, including holes for a 1/2-in. diameter anchor screw or bolt, or for two 1/4-in. diameter concrete screws positioned to allow a variety of fastening options.

ForConstructionPros.com/21821425

ForConstructionPros.com/21952818

The Steele Mixer by SteeleHouse Industries

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BY PAUL JAWORSKI

The History of the Internal Concrete Vibrator & The Rise of the Controlled Frequency Design Industry studies have highlighted separation issues, vibration energy, surface defects and mix incompatibilities — leading to the development of a more predictive concrete placement experience.

Adobe Stock Images | By Branko

O

ver the last 60 years, concrete vibrators have evolved into a necessary machine for concrete jobs. Industry studies have highlighted separation issues, vibration energy, surface defects, and mix incompatibilities— leading to the development of a more predictive concrete placement experience.

Concrete vibration dates to the late 1960s when Thomas Reading, an engineer from the U.S. Army Corps of Engineers, set vibration placement recommendations through vibration tests. At the time, the normal slump of structural concrete was three to four inches, had a “peanut butter” like consistency, and placed in forms by a concrete bucket.

Reading used a larger horsepower motor to maintain a maximum vibrator speed that ran the vibrator heads for the current consistency of mixes. Reading concluded that the vibrator frequency should never exceed 10,000 vibrations per minute (vpm) due to his observation of concrete material separation.

At that time, the American Concrete Institute (ACI) 309 Consolidation Guidance Specification reflected Reading’s research and limited the vibrator frequency to that maximum frequency.

Ten years later, mix designs were being transformed by a water-reducing agent (WRA) to allow for a more workable concrete mix for the future of economical concrete placements by pumping instead of concrete buckets. By the end of the next several decades, the volume of pumped commercial concrete reached 80%. The increased use and type of WRAs (plasticizers) allows for more possibilities of bleeding.

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With the increased bleeding in pumpable mixes, present concrete mix designs started to take on a "soup-like" consistency. While the vibrator design remained the same, manufacturers began to increase the amount of vibrator frequency. As a result of this vibrator design frequency disconnect, surface defects began appearing on the form face of freshly poured concrete surfaces.

These surface voids were mistaken for entrapped air and even more vibration energy was added by contractors to try to alleviate the problem.

Through today’s research, we’ve come to understand that surface blemishes come from vibrationfrequency-forced bleed water.

The available water is a product of the WRA-induced hydration delay that makes pumping easier. In these WRA mixtures, the higher the vibrator frequency, the more water is moved to the form faces.

THEN, EVERYTHING STARTED TO CHANGE In the late 1980s, the Federal Highway Administration (FHWA) and pavement industry representatives evaluated the long-life road design that was constructed in Europe. From the implementation of European road designs in the U.S., the pavement vibration approach had to be changed to meet new pavement mixes. By developing a controlled frequency vibration (CFV) system in coordination with an FHWA study, many vibrator design specifications were changed along with the product: the vibrator offcenter weights were increased; vibrator

frequency was limited to 4,000 to 8,000 vpm; and vibrator centers were lowered from 24 to 16 in.

The study used data that came from the vibration monitoring and control system to set pavement construction specifications to limit the material separations, which were causing surface bubbling and scaling, aggregate displacement, and uneven patches of surface texture. The developed standards are in use today by individual state department of transportations (DOT), airport construction, and several other infrastructure placement practices.

THE EFFECT ON VIBRATOR DESIGNS FROM CONCRETE MIX FORMULAS Learnings from resolving concrete paving vibration issues have been applied to commercial-use concrete that has been over-vibrated since the mid-1980s.

The lack of vibration industry controls, field research, standards, or innovative designs to deal with the rising level of over-vibration was becoming an issue with the increase of form face defects.

These surface defects are originated from the available water movement caused by high vibrator frequency.

While FHWA studies were conducted for roads, commercial concrete studies were not funded to evaluate the origins of having to patch freshly poured concrete.

Even without a funding source, the concrete material separations of water, aggregates and micro air by vibration frequencies in commercial construction still needed to be addressed. The

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industry vibrators that were used to vibrate concrete in the U.S. were brought in for evaluation as part of a study. An identical vibrator in horsepower, shaft size and head diameter was obtained from five leading manufacturers and evaluated. The study concluded that all evaluated vibrators ran higher frequencies than the original ACI specification, and all ran differently from manufacturer to manufacturer, meaning the vibrator user had a very little chance of solving vibration patching issues.

The chosen method of evaluating the issues with commercial concrete placement by vibration was to control the energy that came out of a vibrator, predict the effects of that energy, and evaluate the energy against a changing concrete variability in batching, transport, and placement.

A VIBRATOR ENERGY WORKABILITY CURVE Pavement control technologies and field study procedures have been adopted and helped achieve empirical behaviors for today’s types of commercial concrete mixtures. From these pre-construction trials, vibrator frequency was lowered from the standard 13,000 to 17,000 vpm range to a compatible range of 6,000 to 10,500 vpm in field trials. This change reduced the phenomenon of driving available mix water of pumpable mixes to the surface of concrete forms.

These unwanted blemishes become visible on the form surface of freshly placed concrete and are routinely misidentified by vibrator operators as air voids from under-vibration when instead, they could be easily avoided.

Although most types of material separation can be traced to vibrator frequency, it is often difficult to understand concrete viscosity versus vibrator frequency compatibility. Now, simplified and easily digestible vibrator energy wave concepts are used in clinical analysis. These concepts will

also be used in the future to help users understand the predictive behavior of both vibrator and concrete variability tendencies upon truck delivery.

The wave concept of a vibrator examines the two waves that propagate from the same vibrating head source.

In vibrator wave behavior, the elevated pulsating pressure waves (p-waves) are better in the consolidation effort than the elevated shear waves (s-waves) that contribute to material separation.

Vibration research has used CFV to study forces at wave values and report performance back to the user. The load curve shows the resistance against the workability of the concrete being vibrated. A workability log can be studied to bridge the gap between predictive vibration energy versus changes due to inconsistent quality in batching, transporting and pumping. In understanding vibration wave energy behaviors, higher p-wave values can be applied for consolidation while limiting s-wave values to limit material separation.

With science-backed research, mapping the concrete vibrator’s behavior and the changes in the concrete workability curve can be understood and better managed. The adjustment to the vibration frequency or wave manipulation creates a more predictive consolidation result.

CONCRETE CONTROL TESTS In the past two years, there has been a large increase in vibration research and funding for future investigations into the issues caused by vibrator frequency and mix incompatibilities. There are several field trials that are conducted annually to look at using the right amount of vibration energy at pre-construction trials to make the construction outcome more predictive. This is done when the contractor prepares several wooden boxes built into 24-in. cubes to test the concrete when pouring their mock-up forms prior to actual construction. The trial boxes are

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marked by the vibrator frequency that the contractor selects—normal trial frequencies are 10,500; 8,000; and 6,000 vpm.

During the pre-construction delivery to the mock-up forms, the boxes are filled and analyzed the day after for evaluation of surface issues.

Researchers are working on quality control tests that can add more data for contractors on the mixture’s bleed tendency or slump variance from the original mix design. The work has helped develop an easy, accurate and repeatable workability meter to dial in on concrete variances and how they will affect concrete construction.

Using CFV and evaluating vibration curves as a source of controlling batching or transporting variances, contractors can receive help in understanding the data that’s being logged by the manufacturer. In collecting job electronic data, the CFV will report a curve that can be compared to the curve that is reported at pre-construction trials.

The variety of industry concrete vibrators all act differently against concrete loads, and to limit patching needs, vibration control and evaluation are the first steps in a predictive outcome.

Vibration compatibility testing should be done in pre-construction trials and contractors should always get help from the manufacturer of the trial vibrator.

Concrete vibrators are a vital part of the workability system. Through years of research and trials, issues caused by over-vibration and concrete material separation are being addressed and limiting the potential patching costs once associated with the vibrator model designs from the 1960s.

Close-up of a poured wall with surface imperfections due to vibrators running too fast.

Minnich Manufacturing

Paul Jaworski is the products manager at Minnich.

Find this article at ForConstructionPros.com/ 21759450.

JANUARY 2022

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FORM YOUR BUSINESS Unsplash

»

BY ALEX BARTHET

3

C

Release Mistakes You Must Avoid

onstruction lawyers are often asked about releases, specifically these three mistakes.

1. USING THE WRONG FORM OF RELEASE WHEN EXCHANGING MONEY FOR A RELEASE The form of partial and final waiver of release that you should use depends primarily on where you are in the chain of contracts.

Try to give the narrowest release possible when you are the one being paid.

That is, giving away the fewest amount of rights when you are receiving a check.

If the role is reversed and you are giving a check, you should try to get the broadest release that you can possibly obtain when you hand over that check.

2. NOT USING A CONDITIONAL RELEASE What happens when you are given a release that says you have been paid when you haven’t been paid? That release goes from you as the sub-subcontractor to the subcontractor who hands it to the contractor who then hands it to the owner. If the release is not conditioned on you actually receiving the money and the owner hands the check to the contractor and the contractor pays the subcontractor who never pays you, you would have no lien rights.

This means that you need to make sure that if you are not getting a check at the time you are giving your release, your release must be conditional.

How can you make your release conditioned upon getting paid? You can add language to make your release conditional: “Notwithstanding anything to the contrary, this waiver and release is conditioned upon and not effective until the undersigned receives payment funds of $_________ .”

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Watch out for releases that are titled conditional but are not. Some say they are, but when you read them, they’re actually not at all. Also, you need to indicate the amount of money to satisfy the conditions. If you’re expecting a $25,000 check, it has to say that it’s expressly conditioned upon your receipt of the $25,000.

As a general contractor if you receive a conditional release from a sub-subcontractor or supply house that you are not actually paying directly, you have to be careful. If you pay the contractor and he doesn’t pay the supply house, this conditional release that you received as the GC from the supply house is now no good because the supply house never got the money.

You can deal with this by requesting an unconditional release or by issuing a joint check. A joint check is a check payable to two parties. This check requires the endorsement of both parties and you will know that the condition of the conditional release has been satisfied.

3. USING THE WRONG THROUGH DATE The through date is the effective date of the release. Every release is different, and it may have a through date written in different places and slightly different ways. The through date is the end date that the release is effective. The most important thing you need to remember is that the through date will have control over the payment amount.

If you pick up a check that is a reduced amount and your release for that payment has a through date later than you’ve actually been paid, you have a problem. Make sure that the through date and the payment match.

A $10 RELEASE? There are two common reasons why a contractor may demand a $10 release.

When you gave a notice to owner but you are not owed during the period. Let’s assume that as a subcontractor on a project you have issued a notice to owner, but you are not actually going to start work for another three months. At the end of the first month, the general contractor may demand a $10 release. The law requires that once you issue that notice to the owner, then the contractor and the owner need to obtain a release from everyone that issued a notice to owner, whether or not they did any work that period. If you haven’t done any work that period, it is common that the amount of money recited in the release will be $10.

When the contractor does not want to disclose to the owner how much the subs and the vendors are being paid. Sometimes, contractors want to shield how much information is given to the owner. This is another common reason why contractors request a $10 release. The $10 is valid if you receive any type or amount of consideration even if that consideration is not exclusively money. If you are receiving money, try to include how much you are receiving. If you are giving money, try to make the release ‘$10.’

Never condition a release on $10. If you want to issue a conditional release, always state the actual amount you are expecting during that period.

Alex Barthet is a principal attorney at The Barthet Firm and writes articles for The Lien Zone.

Article originally appeared on thelienzone.com. Adapted from ForConstructionPros. com/21109938 .

www.ForConstructionPros.com/Concrete

12/28/21 9:42 AM

BOOTH D420 Curb Roller Manufacturing

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BY JONATHAN KOZLOWSKI

Adobe Stock Images | By Jason

Q&A on Carbon Neutrality We spoke with Rick Bohan, VP of Sustainability for the Portland Cement Association, about their Roadmap to Carbon Neutrality.

Q:

How does the Roadmap address carbon neutrality?

We're looking at an entire value chain. We call it the five C's: Clinker, Cement, Concrete Construction, using Concrete as a Carbon Sink. But realistically, everybody that touches that value chain has a role to play. Of course, the plant—whether it's a cement plant or a concrete plan—but people in construction too. That means the people that are building, the people that are doing the build-outs, the designers, the architects, the engineers, people that operate those buildings.

If you think about it, all of society, because essentially, we're all using concrete to one degree or another, either as a user, a consumer, a buyer, an owner… we all have some level of involvement with that value chain.

Are there goals? How can we track this going forward?

Absolutely. Each one of the steps in the value chain has targets for 2030, 2040, and of course, by 2050. For example, we'd like to increase, almost

Q:

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double, the use of decarbonated raw materials at a cement plant. Why? Because that goes to a direct reduction of the amount of CO2 released from that chemical. Fact of life. Today, we're just under 5%. By 2050, we want to get to 10%. Now there's a limit because there's an availability issue of those materials. But that's one example.

Reducing the clinker to cement ratio in our cements. Increasing the use of alternative fuels. We've got a number of graphics throughout our Roadmap that show what each of these levers can bring to the table. Our goal is to report on the Roadmap and the progress with each one of those. I envision that some years are going to be better than others.

And we may see where some levers have more impact than others. But, on the whole, we've got these targets aligned, and we're really excited about it. And of course, the angle, carbon neutrality by 2050. But look, I'm really optimistic. I think we can do it sooner.

This really goes to the point about using the entire value chain. There's a lot of focus right now on cement and concrete. But you know, even if you ratchet down the CO2 with cement and concrete, you still have the issue of construction itself. How can you lower the embodied carbon of the construction process itself?

There are metrics that we're going to have to develop. Things like, how

do you measure the CO2 footprint of the construction process? We're really excited to be engaged with some of the largest contractors in the world, to start to define metrics for that, so that we can actually measure it. Because if we can't measure it…we're really not holding ourselves accountable. I'm really big on making sure that number one, we're completely transparent with the Roadmap, transparent with our targets, or timelines, the technologies, our policies. And number two, accountable.

It's not enough to have the Roadmap, we have to show how we are progressing.

We're really proud that we are taking the lead on that as an industry.

It's not like the cement industry and the concrete construction industry is doing this alone. There's the steel industry, which has its own segment.

There's a supply chain in this industry of the trucks and the trains and the shipping internationally. All of them have effort going into reducing their emissions. This is just our part.

Our hope is that they will look to the US cement industry for a template of how you can do this. We're going to be cooperating with other industries because we don't operate in a vacuum.

So, I think there are lessons we can learn from every other industry that's doing this. Likewise, there are lessons they can learn from the cement industry. We're excited about that.

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12/28/21 9:46 AM

Portland Cement Association

Q:

What should contractors ask their plants about?

Don't ask the plant. First, go to the owner and be very intentional. Say, “What are you trying to do with this building?

How quickly do you want to build? How will it be used?” and so forth. Sit down with the design team and become part of that team effort. It shouldn't be just the contractor, it should be everybody coming to a consensus saying, [using a high-rise building as an example] “We don't need real high strength for these lobby columns because it won't be occupied for another eight months. So, how about instead of a 28-day strength, we use a fixed 56-day strength?” Now you can go to the concrete supplier and say, “I don't need strength until 56 days, what can you guys do for me?” [The concrete supplier] can then go to the cement supplier and say, “What are the options we can provide this guy?” Make it a team effort.

I think people come up with the answer that they want. And they say, “This is what I need.” I think that's backwards. I think what they should do, again, be intentional about it, and put the question to the entire value chain: “How can we optimize this [project]?”

If you think about it, a lot of this depends on circumstances. If I'm replacing the I-35 Bridge in the Twin Cities, and I've got hundreds of 1,000s of cars that are passing over it every single day, I may not have time to use the 56-day strength. I may need an optimized structure. I may need a higher strength concrete, but I can still do that with a lower embodied carbon depending on what's available in my area. It's a balancing act and it's an optimization act.

What can contractors start addressing right now?

If you think about construction, in general, you have four primary phases.

You've got the design phase. Contractors should be involved in the design phase because they have the know-how about means and methods. They're the ones that can tell the architects and the engineers, “This can't be done” or “If you want to do it this way, this is the cost.”

Q:

I don't mean cost in terms of money but also cost in terms of time. Costs in terms of carbon footprint. They have to be brought in the design phase early on. This is where you get into issues like BIM and augmented reality, workflow, processing, and things of this nature.

Then the construction phase. If you go to a job site here in the US…more often than not, it looks like utter pandemonium. There's chaos. Whereas if you go to job sites in some parts of Europe, you wouldn't recognize it because it is almost a sterile environment. By sterile, I don't mean so much clean, but it's orderly. They have sequenced everything out to the last, you know, hour and minute of the day. When things will arrive, how they arrive, how they'll be installed, who will be on-site, when they're on-site. There’s a lot of money to be made by being the innovative designer, the innovative contractor, those are the folks that are making bank.

You're also employing people.

You're giving your workforce great opportunities to be involved with a company that isn't just changing the world for the better. And quoting this building out there, that's going to last for decades, you're also providing an economic engine.

In the use phase, concrete has such a huge role to play. We know that concrete buildings with the thermal mass, resiliency, fire resistance, earthquake resistance, the fact that a concrete building can stay in operation 24/7 through tornados, hurricanes, fire, windstorms, floods—that has a huge dividend; that cuts operating expenses for a building.

And then finally at the “end of life,”... using that concrete building decades from now for fresh concrete with…other types of cements using that for new [buildings.] That's the role contractors have to play. I get passionate about it because I'm so excited. This is today's technology ready for people willing to take the opportunity.

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What I would love contractors to do is download our Roadmap and put up the graphics. Put those up in their jobsite trailers. In their offices. Point to them and say, “This is what they want to do. How can we contribute to that?” And you know what, there's a role for them to play. Maybe they become more willing to accept portland limestone cements. Maybe they become more willing to look at their workflow. On the construction site, maybe they become more willing to look at zero-emission material handling equipment on the jobsite.

Things like that. I think if they do that, if they start thinking outside the box, and start what-iffing.

The one chart that I would ask them to really focus on: optimization.

They're shifting the curve and shaping the curve, but the one I want them to focus on is shifting the curve. You have some of the most innovative contractors out there. They're the folks pushing the envelope every single day. If I was a contractor, I'd want to be one of them. That's where I want to have my company, my staff, pointing to that star performers saying, “Look, folks, we're going to be at the cutting edge in our company in what we do, how we do it, when we do it, and where we do it.”

That's what I'd like them to do.

I'm passionate about it. I'm excited about it because we have a solution. I would encourage everyone that if you have questions, if you want to put us on the spot, if you've got input, we're here.

Listen to this on the Digging Deeper podcast, "Society Needs Concrete; Concrete Needs Society", ForConstructionPros. com/21796418 (part 1) and ForConstructionPros.com/21796419 (part 2)

Find an expanded version of this interview at ForConstructionPros. com/21808706.

JANUARY 2022

CONCRETE CONTRACTOR 37

12/28/21 9:47 AM

Adobe Stock Images | By rost9

BY THOMAS VAN DAM, PH.D, P.E.

Carbonation: Quantifying a Sustainability Benefit of Concrete Pavement

F

rom the smallest local agencies to state DOTs, there’s been a growing emphasis on making infrastructure more sustainable and resilient.

Accelerating this is the November 2021 Infrastructure and Investment in Jobs Act which incentivizes the use of local materials, such as concrete, and funds investment in the decarbonization of such materials. Most of concrete's carbon emissions are associated with manufacturing portland cement, but concrete is a long-lived material and that lifespan reduces the impact of the carbon produced during its manufacture over the extended service life.

There is another, less-talked-about way in which concrete contributes to sustainability: carbonation. During the production of portland cement, limestone consisting of calcium carbonate is added to the kiln. When heated to a high temperature, the calcium carbonate (CaCO3) converts to lime (CaO)—the product required for portland cement production—and CO2, which is released into the atmosphere. But a partial reversal of the process begins once the portland cement is hydrated during

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and after construction. As the concrete surface is exposed to atmospheric CO2, the calcium hydroxide and calcium silicate hydrate in the hardened cement paste react chemically with the CO2, converting back to limestone and recapturing the equivalent of some of the CO2 emitted during production.

This carbon capture is known as carbonation, and over the life cycle of a concrete road, the potential for carbonation, although small, is significant.

HOW MUCH CARBONATION CAN OCCUR IN A TYPICAL U.S. CONCRETE PAVEMENT? Research by Anderson et. al quantified concrete’s uptake of CO2 by carbonation[1]. One factor that determines the amount of carbonation taking place is exposure, i.e., whether the concrete is exposed to rain, sheltered from rain, indoors, or underground. The amount of exposed concrete surface area, the quality of the concrete, and the amount of cement also affects the amount of carbonation that takes place. As an example, a typical U.S. pavement can be assumed to be a 564 lbs./yard3 portland cement

mix with a compressive strength of 4,000 psi and exposed to rain. Based on this, the amount of CO2 sequestered through carbonation is calculated to be between 0.2-0.3 lbs./ft2 of surface area in 50 years, which translates to roughly 14,00020,000 lbs./lane mile.

An important observation is that concrete’s rate of sequestration decreases with time because the calcium carbonate begins to fill up void space in the concrete. This “pore blocking” effect slows the penetration of carbon dioxide into the concrete, so the rate of carbonation decreases at roughly the square root of time. The result is that about 45% of the carbonation that occurs over 50 years happens by year 10.

In a typical pavement, approximately 2-3 mm of carbonation may occur in the first 2-3 years, whereas by year 20, the total depth of carbonation is only 5-8 mm, with little additional carbonation occurring beyond year 50.

The most practical way to counteract this decrease is to remove the carbonated surface and expose uncarbonated paste— an action most effectively accomplished through diamond grinding the pavement

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12/28/21 9:49 AM

surface. Diamond grinding reopens the pore structure and exposes fresh calcium hydroxide and calcium silicate hydrate while also increasing surface area. Once a carbonated pavement surface is diamondground, the process of carbonation starts over. It’s worth noting that a typical pavement reconstruction strategy—overlaying the concrete with asphalt—seals the pavement against atmospheric CO2 and terminates sequestration.

GETTING THE MOST SUSTAINABILITY BENEFIT FROM CONCRETE PAVEMENTS Carbonization is one of several ways in which concrete’s natural benefits can be optimized. Proper maintenance of a pavement is key to extending its life and lessens the amount of new construction. Less construction not only equates to less material acquisition, processing, and construction but also reduces congestion due to construction delays, thereby reducing vehicle greenhouse gas emissions. Keeping smooth pavements smooth is another way to reduce vehicle greenhouse gas emissions; it is well-documented that vehicle fuel efficiency is related to the smoothness of the pavement (by sources such as the World Bank HDM 4 model and recent research by NCHRP, Caltrans, and organizations in Europe).

Even considering there are some greenhouse gas emissions associated with concrete pavement preservation tasks

(e.g., minor repair and diamond grinding), these are relatively small compared to those incurred due to rehabilitation or reconstruction. Yet the overall ecological benefits of concrete pavement preservation, especially diamond grinding, are such that they likely offset the emissions due to the preservation activity.

Conventional triggers and time frames for concrete pavement preservation may not optimize carbon capture or other concrete sustainability benefits.

Currently, concrete pavement preservation featuring diamond grinding is most often performed when a pavement is showing advanced stages of distress.

Typically, agencies and other road owners assess road roughness using the International Roughness Index (IRI) and often do not trigger treatment until a high IRI threshold value (180 in./mile or more) has been reached.

According to studies performed by Wang et al., IRI trigger values should vary according to the amount of traffic on a given road to maximize sustainability benefits[2]. For roads with daily traffic of roughly 2,500 vehicles or less, there is no optimal IRI trigger value based on greenhouse gas reduction whereas the recommended trigger value for pavement preservation of roads where daily traffic is between 2,500 and 12,000 is reduced to 152 in./mile. For roads with roughly 12,000 to 34,000 vehicles per day, 127 in./mile is the trigger value and for roads seeing more than

34,000 vehicles per day, the recommended IRI trigger value is 101 in./mile.

With a more deliberate timing of preservation projects, the sustainability benefits of concrete pavement could be even greater than they currently are. Diamond grinding can be successfully performed on the same pavement multiple times. If diamond grinding were to be routinely performed on a 10-to-15-year cycle, not only would vehicle-emitted carbon dioxide be significantly reduced through improved smoothness, but there would be a renewed rate of carbon dioxide sequestration. In fact, diamond grinding every 10 years would more than double the amount of sequestered CO2 over a 50-year period. (See figure 2.)

Preserving concrete pavements to a high level of serviceability is inherently a sustainable solution. The above approach represents a rigorous quantification of the benefits of diamond grinding, making it easy to assess its advantages. Grinding concrete surfaces not only keeps them smoother and quieter, but also can more than double the amount of CO2 sequestered over a 50-year design life. By comparison, carbonation would happen more slowly on unground pavement—and not at all on concrete once covered with asphalt.

Thomas Van Dam, Ph.D., P.E., and Principal, NCE specializes in pavement design evaluation, forensic investigations, materials assessment, sustainability and resiliency.

REFERENCES 1

2

Anderson, et. al. 2019. “Carbonation as a method to improve climate performance for cement-based materials.” Cement and Concrete Research, Vol. 124, (October 2019) 105819.

Wang, et. al. 2013. “Network-Level Life-Cycle Energy Consumption and Greenhouse Gas from CAPM Treatments.” Research Report: UCPRC-RR-2014-05. University of California Pavement Research Center, UC Davis, UC Berkeley http://www.ucprc.ucdavis.edu/PDF/ UCPRC-RR-2014-05.pdf

Find this article at ForConstructionPros.com/ 21928107.

Figure 1. Diamond grinding pavement every 10 years would more than double the amount of CO2 sequestered over a 50-year pavement life span.

NCE

www.ForConstructionPros.com/Concrete

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JANUARY 2022

CONCRETE CONTRACTOR 39

12/28/21 9:49 AM

SPECIFICATION GUIDE: FORMS 1

3

5

1. Form Tech Concrete Forms Inc., PolyMeta Forms

6

4

2

Company & Product

7

Pour Rating Pressure

Compression Strength PSI Value 3

Material

High Density Poloythylene and Steel Pockets

Placement

Hand-set

Panel Dimensions

Height: 12 ft. sections (stacking pockets to reach 8-18 ft.)

Width: 4 in.

Panel Weight

Form Face Type

Grade of Finish

URL

12.9 lbs. (4 ft. Straight); 7.7 lbs. (4 ft. Flex); 15.5 lbs. (6 ft. Straight); 10.5 lbs. (6 ft. Flex)

High Density Polyethylene

Construction

ForConstructionPros.com/ 21927943

8 lbs./sq ft.

1/2 HDO Plywood

Construction

ForConstructionPros.com/ 21927963

4 lbs./sq. ft.

Polymer

Class B (Surface to receive plaster or stucco)

ForConstructionPros.com/ 12314803

34 lbs.

Wood

Construction

ForConstructionPros.com/ 21940839

10.55 lbs./sq. ft.

(3.3 by 2.4 m panel)

18mm Birch Plywood with water repellant treated top veneer

Class B – Suitable for some high finish requirement projects

ForConstructionPros.com/ 21940847

7/8-in. thick Xlife Plywood

Class A Surface with a Surface Finish of SF-3.0 (offset between the frame and the plywood could result in a Class B finish with a Surface Finish of SF-2.0)

ForConstructionPros.com/ 10207336

Wood

Can provide any finish requirements

ForConstructionPros.com/ 21940857

Depth: 6 in.

Height Range: 3, 4, 5, 6 & 8 ft.

(Gang forming to reach higher heights)

2. Form Tech Concrete Forms Inc., Steel Ply Forms

1,000 psf, consult an engineer for unique application ratings

Steel with Wood Facing

3. PERI Formwork System Inc., DUO

1,050 psf (wall), 1,650 psf (columns)

Fiber Reinforced Polymer

Hand-set

135 by 90, 75, 60, 45, & 30 cm; 60 by 90, 75, 60, 45 & 30 cm; and 15 x 10 cm

Aluminum

Hand-set

4.92 by 2.46 ft.

4. PERI Formwork System Inc., SKYDECK

5. PERI Formwork System Inc., MAXIMO

6. Doka USA, Frami Xlife

7. Doka USA, Superdek

1,650 psf

1,200 psf for panels at 2 ft. 6 in. to 6 in. wide (with 6-in. intervals) 1,500 psf for panels 2 ft. to 6 in. wide (with 6-in. intervals)

Width: 24 in. with filler sections ranging to 1 in.

Power-coated Galvanized Steel

Height Range: 3.3 m, 2.7 m, 1.2 m, 90 cm, 60 cm & 30 cm Crane Width Range: 2.4 m, 1.2 m, 90 cm, 60 cm, 45 cm & 30 cm Height Range: 3, 4, 6 & 9 ft.

Steel with Wood Facing

Hand-set or Crane

Width Range: 1 ft. 8.5 in. & 4 ft. 7 in.

7 lbs./sq. ft. (approximate)

Depth Range: 3 ft. to 6 in. with 6-in. intervals

n/a

Aluminum

40 CONCRETE CONTRACTOR

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Depends on Heights

Hand-set

Stringers Length Range: 12, 8, 6, 5 & 4 ft.

Joist Length Range: 8, 6, 5 & 4 ft.

www.ForConstructionPros.com/Concrete

12/28/21 9:50 AM

SPECIFICATION GUIDE: COMPACT CONSTRUCTION EQUIPMENT THE AW16-B BATTERY-POWERED WHEEL BUGGY The Allen AW16-B battery-powered buggy has been uniquely designed and tested for jobsites and projects where emissions are a major concern. The Allen AW16-B Power Buggy is powered by a rugged Vanguard 48 Volt Lithium- Ion power pack capable of reaching 8-9 hour run times. There are many features that make the AW16-B the most durable and versatile battery-powered buggy on the market.

ForConstructionPros.com/21952846 Name of Equipment:

Type of Equipment

Dimensions (L x W x H)

Weight

Weight Capacity

Speed (if applicable)

Multiple Attachment Options

Engine

AW16-B

Battery-powered Wheel Buggy

97 by 47 by 50 in.

1,507 lbs.

2,500 lbs.

6 mph

No

48 Volt Lithium-Ion Battery

WERK-BRAU SKELETON ROCK BUCKET Werk-Brau Skeleton Buckets are specifically designed to separate large rock and other debris from smaller loose materials. Available in various widths and sizes for either loaders or excavators. Manufactured with high-strength T-1 steel in all critical wear points, with abrasion resistant wear straps to reinforce the bucket bottom. Tapered side plates reduce wear on the bucket and allow for easier dumping. Werk-Brau Skeleton Rock Buckets are ideal for quarry work and anywhere that larger materials are sorted from smaller, loose materials.

ForConstructionPros.com/21809368 Name of Equipment

Type of Equipment / Use

Dimensions

Skeleton Buckets

Rock Sifting

Various widths available

Weight:

Weight Capacity

Speed

Multiple Attachment Options

Engine

2.75 to 7 cu. yd.

n/a

n/a

Powered by Wheel Loaders with a 2.5 yd. capacity and greater

KUBOTA CC30 CONCRETE CLAW The Kubota CC30 Concrete Claw is used for digging and removing large sections of concrete floors, driveways, sidewalks, and other large slabs. Simply slide the teeth under a concrete slab, lift and load the slab under the pin-under top for clean and efficient concrete removal. The CC30 Concrete Claw is manufactured by Land Pride, a Division of Great Plains Mfg. Inc. a Kubota company and features a universal quick-attach hitch that fits a wide variety of loaders and makes the attachment easy to attach. Its high strength T1 steel side panels resist bending forces while prying up concrete slabs and the side panels are reinforced to add strength and rigidity to the attachment. The Concrete Claw is performance matched with Kubota’s SSV and SVL Series.

ForConstructionPros.com/21113973 Name of Equipment:

Type of Equipment / Use

Dimensions (L x W x H)

Weight

Weight Capacity

Speed (if applicable)

Multiple Attachment Options

Engine

Kubota CC30 Concrete Claw Attachment

Digging and removing large sections of concrete slabs

63 1/4 in. by 45 3/4 in. by 21 in.

590 lbs.

n/a

n/a

n/a

100 hp maximum

FECON RK6015 STANDARD-FLOW MULCHER HEAD Fecon introduces the RK6015, a new, wider, standard flow mulcher head which is ideal for use with most standard skid steer loaders, Avant-type wheel loaders, and other carriers that are able to provide 17-27 gpm of hydraulic flow, have enclosed cabs that can be properly protected with the appropriate polycarbonate guarding, and have the ability to carry the 1,465-pound attachment.

This new brush cutting tool allows those with standard flow skid steers up to 75 HP to expand their capabilities and enter the brush cutting arena without a large capital expenditure. A bitelimiting split ring rotor holds 26 knife or carbide-type cutting tools and has a 60-in. working width.

ForConstructionPros.com/21771856 Name of Equipment

Type of Equipment / Use

Dimensions

Weight:

Weight Capacity

Speed

Multiple Attachment Options

Engine (Type, Fuel, horsepower, 4WD or 2WD):

RK6015 Standard Flow Mulcher Head

Brush Cutting

60 in. Working Width

1,465 lbs.

n/a

2,400 rpm

n/a

Powered by skid steer, 17-27 gpm hydraulic flow

www.ForConstructionPros.com/Concrete

CONC0122_41_SpecGuidesCompact.indd 41

JANUARY 2022

CONCRETE CONTRACTOR 41

12/28/21 9:52 AM

THE LAST PLACEMENT

»

BY BRAD HUMPHREY

Adobe Photoshop | unknown

What to Say When Your Customer Says 'Your Price is Too High'

M

ost contractors who are confident in their estimating and desirous of making some money will hear some of the following comments from customers: • “Gosh, I didn’t think it cost this much.”

• “OK, is there any sort of discount if I pay cash?”

• “Well, guess I’ll need to wait till next year.”

• “I’m still waiting on some other estimates.”

• “That’s quite a bit higher than I thought it would be.”

Every one of these comments from a customer can be code for “You’re too high!” So, how do you overcome this most obvious of objections? Let me share two time-tested techniques that might help 1. PUTTING COST COMPARISONS IN PERSPECTIVE When a customer responds with, “Your bid is too high,” try the following; remember to be respectful: “Mr. Jones, I noticed that you drive a newer model Chevrolet Impala. I’m sort of interested in the difference in prices of cars from one year to another. Did you know that an Impala in 1987 cost about $13,500?

When I checked on a late model Impala I found that the price is now about $26,000 with a few simple bells and whistles on it.”

While I really want to say, “Look, Mr. Jones, everything in life costs more than it did in the past…and you know it…

‘Knuckle-head.’ “ Of course I wouldn’t say this to his face…but I’d think it.

One clever client of mind actually has a few marketing pieces that show a car model, the Taurus in one example,

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JANUARY 2022

and what it cost new in 1984 and what that same car model, with a picture, cost in 2013. He actually uses this early in his relationship-building to “soften the underbelly” of the customer so the customer isn’t so price shocked when he gets a bid to overlay or sealcoat a parking lot.

Some customers think they know more about construction than any contractor alive. Fewer customers know anything about pavement maintenance.

And still fewer customers have a clue as to what materials, labor, equipment etc. cost today. Don’t get defensive when customers hit you with “You’re too high” comments. Go on offense!

Now, while we might find that certain mark-ups might not land work in one area of our market, don’t give in too quickly before reminding customers as to what they’re paying for other services and products.

2. TURNING A CUSTOMER’S RESPONSE TO YOUR COMPETITOR I’ve had clients who have shared with me that a customer will actually tell them something like, “Your bid is $10,000 more than the other two I received. Why are you so expensive?”

Don’t let this question put you back on your heels. Respond to them with something like: “Well, before I address this, let me ask you Mr. Jones, why do you think they are $10,000 ‘cheaper’ than my bid? Let me share with you why they can afford to be ‘cheaper’ than my bid. They talk ‘quality’ but I give you a warranty.

They talk about ‘quality craftsmanship,’ but my guys have a combined 75 years of expertise and we take you on a pre-start

jobsite walk, a mid-completion jobsite walk, and a post-job walk, taking pictures all along the way for your benefit.

They talk about ‘great customer service’ but we provide you with a work schedule before we start and confirm each completion point through the end of the project.

And, they talk about ‘safety’ but my guys are certified for 20 hours of safety training with a recognized safety inspector.”

How much more impressed will the customer be with your response over just a dealing with a higher bid?

Keep one final thought in mind here: Most contractors know enough not to argue with a customer. But this doesn’t mean we should put our tail between our legs and walk away without a credible, and respectful response!

This second point is less argument and more defining the “unique selling proposition” that differentiates your from your competitors. You might be quick, smooth, and calm explaining those items that make you different, and therefore better, than your competition.

Here’s to separating your company from the competition.

Known as The Contractor's Best Friend, Brad Humphrey continues to write and speak in support of the construction industry. His podcast, 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., he continues to develop, teach, write and share his 35-plus years of industry knowledge.

For more from Brad Humphrey, visit ForConstructionPros.com/ contractors-best-friend.

www.ForConstructionPros.com/Concrete

12/28/21 9:59 AM

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