Dream Catcher Project Highlights Contractorâ€™s Best Decorative Talents
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Preparation is the Key to
POLISHED OVERLAYS 42
OROVILLE Spillway DAM Incident 12
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April/May 2019 | Issue 3, Volume 19
WHAT’S INSIDE Departments
Cover Photo Credit: DWR
4 Editor’s Letter 6 Legal Matters 38 Foundations Q&A 50 The Last Placement
What’s Online Wireless Concrete Maturity Sensors Speed Construction Completions
Cover Story 12 The Oroville Dam Spillway Incident
A rush against the clock to protect the Oroville Dam.
30 Specification Guides: Screeds
Features 8 Two Records Within a Month Two record-setting continuous concrete placements accomplished within a month of each other in Washington state
A compilation of technical information when choosing your next screed.
Giatec concrete sensors measuring concrete’s actual curing help recover schedule delays at Seattle International Airport Search: 1059913
S.T. Wooten Challenged to Shave 1 Year Off I-85 Paving Project S.T. Wooten has been tasked with completing the massive project in 4 years instead of 5. Search: 21061468
20 Dream Catcher Project Highlights Contractor’s Best Decorative Talents Emil Gera has been developing his decorative concrete skills for the past 13 years to expand his father’s concrete finishing business, and it’s evolved well beyond the initial days of simple patio stamping.
26 Technology is Integral . to Concrete Paving Millimeter GPS raises the bar.
36 3 Benefits to Using Propane for Concrete . Construction Equipment
42 Preparation is the Key to Polished Overlays In the world of concrete overlays…it’s what lies beneath that matters most.
How the alternative fuel can help reduce costs and emissions for concrete contractors.
46 Beat the Grind with a . Pre-separator A pre-separator can improve extractor’s performance, giving you longer run times and more.
www.forconstructionpros.com/concrete | April/May 2019 | Concrete Contractor 3
4/11/19 9:42 AM
PCA 2019 Spring Forecast Announced
n a recent press release from the Portland Cement Association, the organization announced its annual Spring Forecast which predicts strong to moderate growth for cement consumption through 2019 and into 2020. PCA Market Intelligence expects cement consumption will grow by 2.3% in 2019; compared to the Fall 2018 forecast this represents a marginal slowing in the pace of growth. “While there are several phenomenon that confront the economy in the next two years, PCA believes the economy is strong,” says Ed Sullivan, PCA Senior Vice President and Chief Economist. “As interest rates rise, they will steal some strength from economic growth. Private construction growth, being an interest rate sensitive sector, is expected to slow under the weight of higher interest rates. Cement consumption growth will slow as a result.” In addition, rising state deficits have forced many states to adjust budgets, reduce costs, and re-prioritize spending. “Absent a new near term infrastructure program, public sector cement consumption is also expected to slow as transportation investment takes a back seat to high state spending priorities,” Sullivan says.
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PCA’s analysis notes the labor market remains strong. On a monthly basis the economy has generated 235,000 net new jobs. While this pace is expected to ease in subsequent years, it is expected to generate more than two million jobs for the next two years. “Overall, the pace of cement consumption growth is expected to soften each year through 2021,” says Sullivan. “In 2022, interest rates are expected to reach their apex and recede slightly. At about this time, the supplemental infrastructure initiative is expected to materialize.”
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Published and copyrighted 2019 by AC Business Media. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording or any information storage or retrieval system, without written permission from the publisher. CONCRETE CONTRACTOR (USPS 021-799, ISSN 1935-1887 (print); ISSN 2471-2302 (online) is published 7 times a year: January, February/March, April/May, June/July, August/September, October/November and December by AC Business Media, 201 N. Main Street, Fort Atkinson, WI 53538. Printed in the U.S.A. Periodicals postage paid at Fort Atkinson, WI, and additional entry offices. POSTMASTER: Send address changes to Concrete Contractor, PO Box 3605 Northbrook, IL 60065-3605 April/May 2019, Issue 3, Volume 19 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).
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4 Concrete Contractor | April/May 2019 | www.forconstructionpros.com/concrete
Concrete Contractor is the Official Media Sponsor of the CFA Foundation Company Certification Program
4/11/19 9:44 AM
Zero Turn for Mobility, A Fun New Spin for Pavers
firstname.lastname@example.org ❘ 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 and move your machine in ways you have never moved before. You’ll be able to pour a tight radius that you could only dream of before. GOMACO’s proprietary G+ controls makes your concrete paver smoother and easier to operate. So, if you want a Zero-Turn GOMACO Paver for your next paving season, you better call now. Our worldwide distributor network and our corporate team always stand ready to serve and assist you. 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 www.ForConstructionPros.com/10073152
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David C. Whitlock has over 25 year’s experience in business immigration, compliance, employment counseling and training. He is the founding attorney of Whitlock Law LLC and can be reached at (404) 626-7011 or at email@example.com.
NEW White Collar Exemption Rule and Steps to Minimize Opioid Abuse
Contractors need to be aware of changing rules in regard to salaried employees, as well as the options available to combat opioid abuse. by David Whitlock
emember almost three years ago when the Obama Department of Labor issued a rule increasing the whitecollar exemption salary test by nearly double. That rule was enjoined by federal courts leading to much litigation and gnashing of teeth. Ultimately, when Trump took office, the Department of Labor announced that it would revisit the rule. They have done so and published in the Federal Register a Notice of Proposed Rulemaking (NPRM) that would revise the salary exemption. The NPRM does several things. First, it formally rescinds the 2016 final rule thereby getting the Department of Labor out of the ongoing litigation. Second, and more important for contractors, the proposed rule would increase the standard salary minimum to $679 per week or $35,308 per year. Third, the proposed rule simplifies the exemption test because it only applies one threshold regardless of the exemption, industry, or location. Fourth, no changes were proposed for the duties tests for the exemptions. In other words, if someone qualified for the exemption before based upon their duties they should still qualify once this rule is adopted in final form. Finally, the proposed rule does away with “automatic” annual updates to the salary threshold.
So what should contractors do now? The Department of Labor anticipates this will probably take effect next January. It is likely that little will change between the proposed rule and the final rule. Prudent contractors will evaluate their pay practices and assess which employees might be impacted by the proposed rule. Then, contractors may have to adjust pay practices by increasing salary guarantees or converting covered employees from exempt status to non-exempt status. Of course, in the latter case, the employee may now be eligible for overtime pay, i.e., time and a half for hours over 40 in a pay period.
OPIOID ABUSE Now let’s talk about a looming issue for almost all contractors. Opioid abuse has reached critical levels. 75% of employers polled by the National Safety Council (NSC) state that their workplace has been impacted by opioid abuse, but only 17% of those surveyed felt that they were well prepared to deal with the issue. Today, more than 100 people die per day from opioid overdose. For the first time in US history, you are more likely to die from an accidental opioid overdose than from a motor vehicle crash. Workplace overdose deaths from alcohol or drug abuse have increased by at least 25% for the last five years.
Other pertinent findings from the NSC survey: Employers tend to focus more upon hiring, benefits, and worker compensation costs than upon the true cost of illicit opioids, but the fact of the matter is that opioid abuse affects all areas of employment. NSC has some very useful tools and excellent educational materials. To find out the true costs of opioid abuse in your workplace, go to www.nsc.org/forms/substanceuse-employer-calculator. You will be asked to enter your industry, location, and number of workers. By providing your email address, you will get an instant report detailing the likely number of affected employees and the probable cost to your business. You will need to partner with your insurance carriers, your medical and pharmaceutical providers, and your employee assistance program providers to deal with this issue. Next, you will need to re-evaluate your drug testing policy and how it’s really working. You will also want to invest in educating your managers and your employees about opioid abuse and prevention. Finally, it almost certainly is worth the investment to increase and ensure confidential access to health care and treatment.
6 Concrete Contractor | April/May 2019 | www.forconstructionpros.com/concrete
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The Contractor’s Guide to Quality Concrete Construction The fourth edition of the best-selling Contractor’s Guide to Quality Concrete Construction is now available in printed and digital formats.
Published jointly by ACI and ASCC, this guide is now 262 pages—over 100 pages longer than the previous edition—and includes full-color photos and illustrations, a new, easier-to-read layout, and substantial content updates. A summary, review questions, and an additional recommended reading list accompany each of the 12 chapters. To learn more about the new Contractor’s Guide to Quality Concrete Construction, contact ACI at concrete.org, or ASCC at ascconline.org.
Written by and for contractors, and referenced by many licensing authorities, this guide details proven practices to produce quality concrete construction.
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FOUNDATIONS / WALLS
TWO RECORDS Within a Month
Two record-setting continuous concrete placements accomplished within a month of each other in Washington state.
new record for the largest continuous concrete pour was set in Washington state for the foundation of the Lincoln Square South tower. However, it was short-lived; as less than a month later, the tower next to it beat the record. Vital to both high-profile concrete pours were Putzmeister placing systems, seven truck-mounted boom pumps and a high-pressure trailer pump — all supplied by Ralph's Concrete Pumping, Inc. of Seattle. The two skyscrapers, part of a $1.2 billion Lincoln Square Expansion II project, offer a 1.5 million square foot mixeduse development in the heart of downtown Bellevue. The site consists of Class A offices, including a six-level, 2,200-car underground parking garage, 231 luxury residences, a 245-guest-room W Hotel, as well as upscale retail, restaurants and entertainment. Having consumed an approximate total of 140,000 cubic yards of concrete, the three-year project is complete with occupancy ongoing. Building the impressive structures was not an easy feat. The area is two city blocks long and one city block wide, so after the earth was excavated, nearly three million pounds of rebar was installed to prepare the site for a 10-footthick concrete foundation. For the first mat, two 40Z-meter detachable placing
booms, plus five 61-meter and two 40Z-meter boom pumps continuously placed 13,400 cubic yards of concrete in 16 hours to set the first record in January 2015. Access to the foundation was 75 feet below street level. In the hole, a 40Z-meter placing boom with a Putzmeister tower was installed in a footing early on, as it would be used for both the mat pour and for the climb to the top of the 32-story high rise. Another 40Z-meter placing boom was also set atop a freestanding tower with a ballasted base. This configuration avoided pouring another footing. From street level, concrete was supplied to each placing boom by two 40Z-meter truckmounted boom pumps. Each unit pushed concrete directly from their hoppers through five-inch pipeline that traveled down the sides of the hole and then horizontally to the two different placing boom towers—the pipe stretched 500 feet to one placing boom location, 175 feet to the other. Meanwhile, five 61-meter boom pumps were set up around the hole's perimeter; they provided long 183' 9" horizontal reaches with plenty of reach to access all parts of the large area. “An enormous amount of strategic planning was required to execute a pour of this size," says Jacob Gribble, co-owner of Ralph's. "Our equipment
pumped flawlessly during the long pour, and all went according to plan."
ANOTHER RECORD Less than a month later, Ralph's was on-site once again to handle a new record-setting pour of 13,690 cubic yards of concrete in 24 hours. This was for the 450-foot tall North Tower (hotel and residences). However, this time, it was not only the size but the complexity of the mat pour that made this both a new state record as well as a feat of ingenuity.
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Gribble notes, "When comparing the two pours, the second one was definitely the most logistically difficult because we had to think outside the box and figure out innovative ways to set up concrete placing equipment as access to the area was extremely limited." Concrete pumps were not allowed to set up in a neighboring parking lot, which would have offered perfect access and convenience to the site. Since permission was refused, creative solutions were developed, which required five placing booms (a mix of 38- and 40Z-meter sizes), six 61-meter boom pumps, a high-pressure trailer pump and literally thousands of feet of pipeline. The mounting configurations of the A new record for the largest continuous concrete pour was set in Washington state when 13,690 cubic yards of concrete was placed in 24 hours for the foundation of the 450-foot tall north tower at Lincoln Square. Photo Credit: Putzmeister America
five placing boom towers varied. A placing boom with a tower on the south side was already in place from the first pour and would be used again and two more towers with ballasted bases were installed outside the mat on the west side. In addition, two footings were poured for two freestanding towers in the middle of the hole (east side). These two towers, in particular, would become a part of the foundation because after the mat pour was finished, the placing boom and upper tower sections were removed, and the remaining 10-foot tower section at the bottom ended up buried in the concrete. To be flush with the concrete, any pieces of the tower section sticking above the concrete were sawed off. Gribble says, "It turned out to be a logical, as well as economical, solution." Supplying the concrete to the five placing booms were four 61-meter boom pumps at street level. The units used their .16H pump cells, capable of up to 210
cubic yards an hour outputs, as well as their standard high-pressure S-Valves, so there was plenty of volume and pressure. Plus, a BSA 2110 HP-D trailer pump, capable of outputs up to 133 cubic yards an hour, was also utilized to pump the concrete. An extensive amount of pipeline traveled down the sides of the deep hole and went in various directions to reach each placing boom tower.
OSS SOLVES SETUP DILEMMA Another resourceful approach to access the pour involved two 61-meter boom pumps, facing cab-to-cab, that were set up in a narrow alley on the north side. The setup in the extremely tight confines was only possible due to the one-sided support (OSS) outrigger system. OSS reduces the outrigger extension on one side of the unit to create an overall smaller machine footprint. In this case, the outrigger width
Brokk Inc. | Monroe WA | 1-360-794-1277 | firstname.lastname@example.org | www.brokk.com www.ForConstructionPros.com/10072268
www.forconstructionpros.com/concrete | April/May 2019 | Concrete Contractor 9
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FOUNDATIONS / WALLS
Ralph's Concrete Pumping supplied the concrete placing equipment to continuously place 13,400 cubic yards of concrete in 16 hours for the first of two recordsetting pours in Washington state. Photo Credit: Putzmeister America
placement for the two skyscrapers, with a crane flying four placing booms among eight strategically placed tower locations. "For a quicker process of flying the placing booms, Series II is an absolute 'must'," says Gribble. Series II features exclusive hydraulic connection technology where the operator can easily couple and was reduced by 10 feet, which enabled a uncouple individual color-coded hydraulic tight fit in the spot. hoses while not under pressure. OSS has been a standard feature Plus, as the placing booms do not on Putzmeister 61-meter boom pumps require counterweight, time and labor since 2006 when the model was introsavings were realized. duced, and its benefit has proven benOther efficiencies were also noted. eficial. Gribble says, "This setup would "With the 50-foot Putzmeister tower, have been impossible without OSS we could pour two floors and then on our Putzmeister boom jump the tower compared pumps." to only one floor per Over 80 mixer jump, which is more trucks from five common with other local concrete systems," explains plants dispatched a Gribble. "This is self-consolidating significant because, concrete mix that with fewer jumps, was specified for the it reduces expensive bottom 18 inches of crane costs." the foundation to ensure When tackling the proper concrete consolidation high rises, Gribble says, where large concentrations "One of the biggest The two skyscrapers, at of reinforcing bars occur. 32- and 41-stories tall relied obstacles was the very hot on Putzmeister concrete The remaining foundation mixes – high strength, placing systems for the rise used a low-heat concrete high heat – which made to the top levels. mix to minimize pumping challenging." To Photo Credit: Ed Sozinho temperature differential accommodate the difficult between the center of the mat and the mixes, two BSA 14000 HP-D trailer exposed top surface. pumps with eight-inch cylinders and "Everything went exceptionally powerful 630 hp (470kW) Cat engines well," says Gribble. "Our Putzmeister provided the power to reach the top level. equipment delivered the necessary They were especially put to the test when volume, as well as provided really they needed to accommodate the 9C smooth concrete outputs during the mixes, which were super hot. The trailer round-the-clock pour." pumps have the capability to provide both high outputs up to 133 cubic yards RISING WITH EFFICIENCY an hour, and high pressures up to 2,176 After two successful mat pours, the psi - both on the rod side. massive six-level garage that covered EXPERIENCE COUNTS the entire footprint, along with a threelevel podium commons area and the The general contractor, Bellevuetwo skyscrapers rose quickly from the based GLY Construction, Inc. is well ground. The larger 61-meter boom known in the region and selected to pumps, with vertical heights up to 197' handle the colossal project. Having 2", were used whenever possible to worked with Ralph's for decades, their place concrete for anything within their past experience led them again to rely reach. However, Putzmeister placing on the company's concrete placing sersystems were the main source of concrete vices. The pumper has been in business
PROJECT SPECIFICATIONS: • Developer: Kemper Development Company— Bellevue, Washington • Architects: Sclater Partners Architects—Seattle, Washington; and HKS Architects • General Contractor: GLY Construction, Inc.—Bellevue, Washington • Ready Mix Supplier: Cadman Heidelberg Cement Group—Bellevue, Washington • Concrete Pumping Contractor: Ralph’s Concrete Pumping, Inc.—Seattle, Washington with 11 locations: Malby, Lakewood, Ellensburg, Wenatchee, Twisp, Moses Lake, Yakima, Richland, Washington: and Portland and Salem, Oregon • Equipment: Putzmeister placing system with 38- and 40Z-meter detachable placing booms with Series II, TG-10 bolt towers with freestanding and ballasted base mounting configurations; 40Z-meter and 61-meter truck-mounted boom pumps; BSA 2110 HP-D trailer pump; BSA 14000 HP-D trailer pumps
Two 40Z-meter placing booms, five 61-meter and two 40Z-meter boom pumps placed concrete to ten foot depths for the south tower foundation. Photo Credit: Putzmeister America
since 1965 so experience is prevalent, and the fleet is expansive, serving customers from eleven offices across Washington and Oregon. Previously under the direction of Skip Gribble, the company is now owned and operated by his three sons—Jacob, Josh and Isaac who grew up in the business. Ed. Note: This feature article was supplied by Putzmeister America.
10 Concrete Contractor | April/May 2019 | www.forconstructionpros.com/concrete
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By Joe Nasvik
THE OROVILLE DAM
12 Concrete Contractor | April/May 2019 | www.forconstructionpros.com/concrete
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A rush against the clock to protect the Oroville Dam.
n February 7, 2017 Lake Oroville was rising due to a series of large storms. That resulted in the use of the Oroville Dam main spillway for flood control. But shortly after opening the main spillway, the California Department of Water Resources (DWR) noticed an unusual waterflow pattern and closed the spillway gates to inspect. Midway down the main spillway a section of concrete floor slab came loose and was swept down the spillway by water moving at about 100 feet per second—52,250 cubic feet per second (cfs). The damage was too much to repair quickly and the need to use the spillway for flood control remained critical. Over the next few days the DWR reopened the main spillway and the damaged area increased in size. It became evident that the rising lake level would cause flow over the adjacent emergency spillway weir for the first time in the dam’s history, so workers began to clear trees and prepare the area downhill. The main spillway sustained damage in what followed; massive erosion and the destruction of a significant portion of the spillway walls and slabs. The high velocity water created a canyon 150 feet deep in the lower half of the spillway. While this was happening the DWR was monitoring the risk to power line damage on the hillside above, potential flooding in the Hyatt Powerplant at In February of 2017 the California Department of Water Resources opened the spillway on the Oroville Dam to reduce the flood water level of the lake. Rushing water destroyed the center portion of the spillway floor, washed away a section of the spillway wall, and created a 150 foot deep canyon in the spillway. With the dam at risk in the event of another flood an emergency construction project commenced to replace the spillway and the emergency spillway beside it.
the base of the dam due to erosion blocking a diversion channel, and the activation of the emergency spillway. The question now was what to do?
THE DAM The Oroville Dam on the Feather River was built in the 1960s and is located in the Sierra Nevada Mountains in northeastern California. It is the highest dam in the U.S. at 770 feet and the second largest reservoir in California, storing approximately 3.6 million acre-feet of water. It produces 841 megawatts of electricity, provides 25 million people with water, and irrigates 750,000 acres of farmland. It is an earthen dam with a concrete spillway and an emergency concrete weir for flood control. The main spillway is 178 feet wide and 3,053 feet long with an elevation drop of 500 vertical feet. The original concrete floor thickness averaged 2 feet and the walls on either side varied from 20 to 34 feet in height. It’s used to control water levels for flood management and provide water deliveries for the environment, agriculture and water contractors. Next to the main spillway is the emergency spillway with a 1,700 foot long concrete weir that passes additional lake overflow over natural terrain to the Feather River.
THE NEED FOR SPEED Ted Craddock, the California DWR Project Manager for the rehabilitation of the spillway project, said they quickly realized the entire main spillway would have to be removed and replaced with work occurring outside the November to April flood season. The first task was to develop a plan for completing this massive undertaking with a very compressed schedule. A typical spillway project would take years to design and construct, but the team had only eight months until the start of the next flood season. Bringing a team of engineers together to begin the new design was the next big step and Craddock says that within a few weeks of the incident, over 100 engineers began design work. He adds, “We also realized that we needed to quickly select a general contractor as they needed to locate a large amount of equipment on the jobsite including crushing equipment and large capacity concrete batch plants.” So they solicited large contractors with proven capabilities in this area and invited them to bid the work, the bid period being only ten days. The Kiewit Corporation, Fairfield, Calif., was the winning bid and got the job. Craddock said the design work started in March and was completed in June. Construction started in May with When the Kiewit Corporation received the contract for the work they had one month to move 500 pieces of heavy equipment to the jobsite, including two concrete batch plants like the one shown Photo Credit: DWR
Photo Credit: DWR
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PROJECT FACTS • Recycled aggregate from the spillway pond: 1 million tons • RCC: 1 million cubic yards • CIP concrete: 160,600 cubic yards • Total amount of rebar: 12,400,000 pounds • Cleaned and vacuumed bedrock foundation: 160,000 square yards • Slab anchors drilled 15 to 20 feet into the bedrock: 7,000 approximately phase 1 construction work completed by Nov. 1 in 2017 and phase 2 work completed by Nov 1, 2018 before the start of the annual flood season. The construction was scheduled to take two years in total. The task for phase 1 involved the repair and reconstruction of portions of the main spillway to accommodate potential flood water releases from the main spillway up to 100,000 cfs by the Nov. 1, 2017 milestone.
CONSTRUCTION IN 2017— PHASE 1 Jeff Petersen, Kiewit’s project manager for the Oroville Spillways Emergency Recovery Project, says that when they started on May 1, 2017, they had one month to mobilize 500 pieces of large
equipment onto the jobsite, including a rock-crushing plant and two high capacity concrete batch plants, one for regular cast-in-place (CIP) concrete and one for roller-compacted concrete (RCC). Thirtyfive construction trailers were also moved on site. “We hired over 100 people to start the project, the number eventually reaching 800 people not counting inspectors and DWR staff,” Petersen adds The challenge for the first year was to remove the damaged portion of the main spillway and make the main spillway serviceable to pass water-flows from the reservoir by Nov. 1, 2017. The work included: • Minor patching and reinforcing the top 730 feet of the main spillway since this section was mostly
undamaged. The spillway walls varied • Replacing the cenfrom 20 to ter 1,050 lineal feet 35-feet in height. Kiewit of the main spillconstructed way where the most gang forms to do the work. damage occurred. Photo Credit: Workers excavated DWR everything down to bedrock, cleaned and vacuumed 80,000 square yards of rock surface, installed rock anchors on 8-foot centers to secure the new concrete, installed sub-drains, and placed leveling RCC. • Removing broken concrete and aggregate from the main spillway diversion pool and recycling it for use as concrete aggregate. • Placing 370,000 cubic yards of RCC
Kiewit used a roller screed with electric winches to screed concrete in an uphill direction. The slope of the spillway was as much as 4:1 and specifications required flatness values of ¼” in 10 feet. Bearings located within the 38-foot wide screed ensured the flatness requirement could be met. Photo Credit: Lura Enterprises
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IT ISN’T LEVEL IF IT ISN’T A LIGCHINE
MORE INFORMATION ON LIGCHINE’S FULL FLEET OF CONCRETE SCREEDS IS AVAILABLE AT WWW.LIGCHINE.COM
4/11/19 10:26 AM
Photo Credit: DWR
in the middle area of the main spillway including filling the 150-foot deep trench in the main spillway created by escaping water, and for construction on the emergency spillway. Mike Rogers, Sr. Civil Engineer and Global Dams Practice Leader for Stantec, San Diego, Calif. worked with DWR to develop and monitor the RCC design features for the project, including concrete mixes and placement. He says part of the aggregates were recycled from the eroded rock dredged from the Feather River following the initial incident. The RCC mix and procedures were designed for quick and easy placement in high ambient summer temperatures, even into the difficult spillway rock foundation with large outcrops and small crack areas. He says they placed 370,000 cubic yards of RCC in 100 days in the center main spillway, including the backfill of the 150-foot
deep trench caused by erosion during the initial incident. The exposed rock terrain at its most difficult point, had nearly vertical side slopes making for challenging placements. A first for the industry, RCC was used to form the steep 4:1 slope of the main spillway using a series of horizontal placements with mechanical trimming to a rough 4:1 slope. A final 12-inch thick enriched RCC layer with a higher strength was placed on the final exposed 4:1 spillway chute surface using specialized equipment to create a strong wearing surface. In another innovation, RCC was used to create temporary side walls in the RCC portion of the main spillway, including the use of Hilfiker Baskets for forming systems with smoothly placed shotcrete finishing. The walls were needed for the 2017-2018 winter season
should the need arise to use the spillway during that interim construction period. Ultimately, the spillway was not used in 2017-2018 and the temporary walls were removed and the enriched RCC chute surface was covered with conventional CIP as designed in the other portions of the main spillway. RCC was also used during the second season of work (2018) in the emergency spillway area to create what workers referred to as “the amphitheater,” a large spillway splash pad sloping downhill with a series of large sweeping 2-foot high steps to channelize flow, resembling a huge outdoor arena. Petersen says they used bulldozers controlled by GPS to place the RCC to the design grade. Then a track-hoe, also guided by GPS, with a custom-fitted vibratory plate attachment shaped and compacted the RCC. “However, it was the skill of the operator
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This shows the detail of the new spillway. The average 7.5-foot thick concrete floor includes RCC concrete at the base and CIP concrete at the finished level. The floor is anchored by drilled rock anchors to the bedrock.
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One of the final steps in the construction involved removing and replacing approximately 15-inches of concrete around each of the four “dentates” designed to direct water flow and spread out its force. Photo Credit: DWR
Most of the concrete was placed when ambient temperatures exceeded 100 F so all the concrete was cooled with ice water and CIP was also cooled with liquid nitrogen (shown here) to reach the specified placing temperature of 55 F. Photo Credit: DWR
mat of epoxy rebar at the top of the slab and a mat of regular rebar at the bottom of each panel. Each panel was 37.5 by 30 feet. The new walls for the main spillway ranged from 20 to 34 feet in height and
were heavily reinforced. They were 2 feet in thickness at the top and 3 to 5 feet thick at the base. Kiewit built their own gang forms to place each the 30 foot wide sections. Kiewit removed 12 to 15 inches of
that was the most important in creating the final shape,” he added.
2018 CONSTRUCTION— PHASE 2 Constructing the finished slabs and walls of the main spillway all occurred in the second year. The RCC work for the emergency spillway was also completed. During the second season, workers completed the installation of rock anchors to hold the main spillway concrete in place, installed the finished main spillway slabs, rebuilt the main spillway walls, constructed a “secant pile wall” consisting of 605 concrete piles, 3 feet in diameter, drilled into the bedrock at 35 to 65 feet in depth to prevent erosion, and repaired the four energy dissipaters or “dentates” located at the bottom of the main spillway. In the main spillway, RCC was used to fill the major scour holes to bring the chute surface back up to the original design configuration, also becoming the base for the 3-foot thick cast-in-place finished concrete spillway slabs with the average total concrete thickness being 7.5 feet. These CIP checkerboard placements included one
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www.forconstructionpros.com/concrete | April/May 2019 | Concrete Contractor 17
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To build a robust emergency spillway Kiewit built an “auditorium” set of steps by using a track-hoe with a vibrating plate to shape and compact the concrete. Operator skill is credited as very important to the ultimate shape of the spillway. Photo Credit: DWR
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concrete from each surface of the four dentates at the bottom of the main spillway. The surfaces were replaced with highly reinforced concrete. The dentates direct the flow of water and reduce its force as it leaves the spillway. They must withstand as much as 5 million horsepower energy forces from the water.
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Nearly all the concrete was batched by the two batch plants on site, one for RCC and one for CIP. Petersen says the RCC mix included two aggregates, fly ash, cement, and ice-cooled mix-water to achieve placing temperatures of 85°F. “The mix was expected to achieve 3000 psi but cylinders broke much higher than that,” he adds. Joe Burke, senior engineer at DWR, says mixes for the main spillway CIP slabs and the walls included three aggregates, cement, fly-ash, silica fume, chilled water, and liquid nitrogen cooling to achieve 55°F placing temperatures. Coarse aggregates and fine aggregate were stored under shade. The mixes were designed to achieve minim strengths of 5000 psi and most of this concrete was placed at night when ambient temps were a little cooler. Both the CIP and RCC walls were cured with a spray-on curing compound.
CHALLENGES Weather. Unfortunately work had to be scheduled during the hottest time of the year when the spillway would not be used. An extended heatwave in 2018 resulted in temperatures during the day as high as 117°F, made all the worse by the south facing main spillway. Petersen says nighttime temperatures were a little better but not much. Kiewit provided shade tents, an unending supply of water, crates of fruit to help workers stay hydrated, training to recognize heat stress, and an on-site medic. Sloped concrete. Kiewit elected to use roller screeds on the 4 to 1 slopes (22.5 degree angles) of the main spillway and contacted Lura Enterprises to see if they had a high production solution. Dennis Lura, the company’s president, says their roller screeds could achieve the specified flatness standard in the 38 foot widths of the floor panels but Kiewit wanted the 3-inch slump concrete to be struck off moving in an uphill direction so a power unit with electric winches was designed to hold the screed and move it uphill at the touch of a button. The resulting 3,500 pound
The finished look of the “auditorium.” All the RCC on the project was cured with the sprinklers and hoses shown in the photo. Photo Credit: DWR
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screed and power unit was built strong enough to be moved by crane. Lura says the screed roller was supported by two “CV joints” (booted joints encasing roller bearings) in the length of the screed to maintain flatness. Kiewit placed checkerboard panels each night, passing the screed over the fresh concrete four times, the last time being half an hour after placement as a final check. Workers used a walk-behind finishing machine with a pan float for the floating step, holding the machine in place by rope. The final finish was hand-troweled. Sloped RCC. Rogers states that placing RCC at a steep 4:1 angle in the main spillway without forms was a first. Using Trackhoes with custom-built vibrating plates to create and shape the emergency spillway “auditorium” steps was also a first. Project duration. The time frame to do the work was very short and was driven by the need to create a useable spillway for the 2017 flood season. The
same was true for the 2018 construction season; the spillway had to be ready for the 2018 flood season starting on Nov 1. Fire. Northern California experienced its deadliest wildfire season in the fall of 2018. The Oroville Dam is located 17 miles away from the town of Paradise and the Camp Fire. Workers were exposed to smoke from the fire and some were evacuated from their homes. There were also evacuation plans for the jobsite if needed.
main spillway was damaged and out of commission. The emergency spillway was not damaged but uphill erosion threatened the structure. But now with the final completion of the construction anticipated in the summer of 2019, the main spillway is much stronger and engineers predict that 270,000 cfs water flows will be safe. The 2.5-foot thick cast-in-place concrete panels were cast in a checkerboard pattern. Photo Credit: DWR
READY FOR USE The contract allowed for 165 construction days for the two seasons of work. When the spillway was first used on February 7, 2017 a water flow of 52,250 cfs produced the first damage to the 24-inch thick spillway floor. In the succeeding next few days, main spillway flows were increased to 100,000 cfs in the spillway and water also flowed over the emergency spillway. By the time the high water levels began to recede the
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By Greg Udelhofen
DREAM CATCHER PROJECT Highlights Contractor’s Best Decorative Talents
Emil Gera has been developing his decorative concrete skills for the past 13 years to expand his father’s concrete finishing business, and it’s evolved well beyond the initial days of simple patio stamping.
mil Gera’s decorative concrete business has grown primarily through word-of-mouth referrals, which is a strong testament for the quality and design elements he’s capable of delivering throughout the
surrounding Weatherly, Pa. market. Emil’s dad (Emil Sr.) started Emil J. Gera Concrete Contractor in the late ’70s, focusing on both residential and commercial slab finishing. Emil began working with his dad in the late ’80s and eventually helped expand the block
The carved stone and wood beam detailing of the fireplace complements the natural stone of the adjacent house. Photo Credit: Emil J. Gera Concrete Contractor
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The outdoor living space Emil J. Gera created displays some of the best decorative work this Pennsylvania concrete contractor has created to date. Photo Credit: Emil J. Gera Concrete Contractor
portion of the business his dad added earlier. As that part of the business grew, it became difficult to find the workers needed to complete the projects. “So, in 2005 I decided I wanted to pursue decorative concrete as a way to grow the business,” Gera says. “For the first couple of years I was just experimenting with stamped concrete. It was a lot of trial and error that led me to seek out some training classes in 2008-2009.” Throughout the years, Gera has continued to attend education seminars at World of Concrete, as well as training sessions held at Concrete Texturing Tool & Supply, the Throop, Pa. vendor who provides extensive training in all aspects of decorative installation. The supplier
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A new aggregate base with 1/2-inch rebar mat two feet on center provides a solid foundation for the six-inch slab. Photo Credit: Emil J. Gera Concrete Contractor
also markets decorative tools, concrete mix designs, choice of sealers, including all the tools and products Gera needs for his decorative projects. Working with a crew of two to three concrete finishers, Gera focuses on building and completing one project at a time within a one-hour drive of “my door.”
NOT YOUR BASIC CONCRETE STAMPING
While Gera’s early work was limited to stamping small patios and sidewalks, the interest and demand for more elaborate outdoor living spaces has propelled his business forward. That is apparent in the elaborate work required in the recent
slate-stamped pool surround patio project complete with a carved concrete fireplace with weathered-looking concrete timbers, and an intricate hand-painted dream catcher design. Gera used a design software to come up with the Western-themed outdoor living space for the space surrounding an inground pool. “Customers want more in their outdoor living spaces,” Gera says. “We designed and produced a look with the carved concrete fireplace that would tie in with the (existing) stone exterior of the home. We also had
The original flagstonecovered patio/ pool surround was in desperate need of an upgrade. Photo Credit: Emil J. Gera Concrete Construction
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to design the project to accommodate a 20-foot by 20-foot timber-framed pavilion that would be constructed in front of the fireplace when we finished our work.” Gera’s crew started by removing the original flagstone patio, demolishing and removing the base material, and repairing some rotted wooden structure of the adjoining house. Other challenges included dealing with electrical conduit that was embedded in some of the old concrete that was removed, and a rainy start to the project in August of 2018, which extended the completion date from four to six weeks.
Gera used Z Pool Forms lined with Walttools Centennial Plank Stamps to create the wood beam edge design surrounding the pool. Photo Credit: Emil J. Gera Concrete Contractor
CREATING A BEAUTIFUL BIG SLAB Seventy-four yards of mix was required to create the new concrete flatwork, consisting of 6-inch-thick 4,000 psi fiber reinforced slab with a ½-inch rebar mat two feet on center. The Canvas integral colored concrete was then stamped using Proline Concrete’s Field Roman Slate Texture with Kingdom Products’ Mystique liquid antiquing.
After Gera completed his concrete artistry, a 20-foot by 20-foot timber-framed pavilion was added to the front of the fireplace feature. Photo Credit: Emil J. Gera Concrete Construction
Wood borders were created using Walttools Centennial Plank stamps, colored with Kingdom Products’ Olde World Stain. The pool edge border was created using Concrete Countertops Solutions’ Z Pool forms and Walttools wood liners custom fitted to the pool forms. The forms were held in place with plastic straps that snapped into the pool liner. www.ForConstructionPros.com/10072749
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A focal point of the project is a dream catcher design Gera created using a stencil and automotive paint spraying tools. Photo Credit: Emil J. Gera Concrete Contractor
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All the flatwork was sealed with Kingdom Products Kingdom Guard Sealer. Gera’s crew began building the conventional masonry, wood-burning fireplace feature by first pouring a substantial footing. After building the concrete block fireplace and chimney structure, with fire box and wood storage box, and then placing an Isokern 42-inch standard fireplace insert, a Spiderlath fiberglass reinforcing mesh was then embedded into the initial base coat of concrete applied over the blockwall structure. The vertical surface to be carved required two pallets of Kingdom Products’ Vertical Wall Mix. Quikrete Q-max was used to construct the fireplace caps and hearth. “We started at the top with enough of the mix for two-inch-thick application four feet down,” Gera states. “We would then use a small trowel to mark off the stone pattern we wanted to create, and then use various tools to carve out the pattern.” After the stone and timber designs of the fireplace were created, Kingdom Products’ Olde World Stains and Regal Seal WB were applied to create the realistic natural look of the structure. Achieving color variation of the carved stones was essential to create the real look of stone and complement the real exterior stone of the home. Gera used a water-based sealer on the fireplace because it does not darken the color of the stain, whereas the chemical-based sealer used on the walking surface provides a more durable surface finish. One the unique features of the project is the dream catcher design created underneath the timber-framed pavilion. Gera used an Oracle vinyl stencil to establish the 7-foot by 7-foot design. He then used his experience with automotive air brush painting tools to create the level of detailing for the final look with Kingdom Products’ Flash-Dye Acetone Stains. The results of all the details require hours to appreciate, and that’s what the homeowners will undoubtedly be doing this summer as they enjoy their new outdoor living oasis.
For a solution based on your needs, visit wrmeadows.com or call 18003425976. © W. R. MEADOWS, INC. 2019
www.forconstructionpros.com/concrete | April/May 2019 | Concrete Contractor 25
4/12/19 8:13 AM
By Jeff Winke
Technology is Integral to CONCRETE PAVING
Millimeter GPS raises the bar.
eauty to behold for the concrete contractor is the smooth, uniform surface of freshly-paved concrete. For them, Concrete Gray is the color of choice in the 64 pack of crayons and nothing feels better than leaving a durable, quality finished concrete paved job for others to experience. The passage of time will reveal any flaws in workmanship, the invasion of water, or the wear from use. Discoloration, scaling, crazing, cracking, or curling will sometimes occur due to a poor ready-mix batch, inadequate curing procedure, subgrade settlement, or improper bonding of the finish-layer. Concrete surfaces are generally very durable, but like everything, they won't last forever–aging and surface wear due
to the abrasion of use will have an effect. Concrete paving is pretty complex and achieving quality, long-lasting results requires skill, the right equipment, and advanced technology. One of the major advantages of concrete pavements is they are typically stronger and more durable than other types of surfaces. They also can be grooved to provide a tough skid-resistant surface. A notable disadvantage is that they typically can be more time-consuming to construct. Thus, concrete contractors have turned to technology for production-enhancing efficiencies and improved results. According to the American Concrete Pavement Association, the role of technology has been significant to the growth and evolution of concrete paving: "Since 1892–when the very first concrete pavement was placed in America–concrete pavement technology has been changing, continually evolving to meet current and future needs."
Topcon Positioning Systems offers a 3D paving capability through its Millimeter GPS paver system. According to Topcon, the product is the world’s first GPS-based millimeter accurate control for pavers. Photo Credit: Topcon Positioning Systems
As part of this more than a century of improvement, the machines and methods have evolved. Today, technology has improved productivity and quality of results. "We're seeing progressive contractors...early adopters embracing technology today, and the others realizing they will have to follow or settle for not being competitive," says Brian Lingobardo, systems manager, 3D road construction, Topcon Positioning Systems, Livermore, Calif. "We have the technology to provide contractors with millimeter paving accuracy, which is astounding." Slipform pavers have become indispensable in concrete paving because of their efficiency in the highly-automated production of concrete road pavements, airstrips, and other large surface sites. The
26 Concrete Contractor | April/May 2019 | www.forconstructionpros.com/concrete
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The system has machine control positioning-zone laser receivers with integrated GPS antenna mounted on the rear of the paver. Other components on the paver include the machine control GNSS receiver and slope sensors to control the front or “draft” of the paver. Photo Credit: Topcon Positioning Systems
track-mounted multipurpose machines are monster-size masters in the production of a countless range of poured, in-place profiles. Controlling their performance to ensure desired results is where machine control developers step in. Topcon Positioning Systems offers
a 3D paving capability through its Millimeter GPS paver system. According to Topcon, the product is the world’s first GPS-based millimeter accurate control for pavers. The system uses satellite positioning together with a zone laser reference. Mounted on the paver is a control box designed to send control to the hydraulics independently. The color, graphical screen displays the machine position on the job, and the sensors being used to control the left and right side of the pan, as well as the current elevation and slope. The system has machine control positioning-zone laser receivers with integrated GPS antenna mounted on the rear of the paver. Other components on the paver include the machine control GNSS receiver and slope sensors to control the front or “draft” of the paver. The Topcon Millimeter GPS paver system features a laser that transmits a unique signal and operates similar to a standard rotating laser. Unlike a standard
rotating laser that only works in a flat plane, the Topcon LZ-T5 transmits a Lazer Zone signal that creates a measuring area 33 feet (10 m) in height. Therefore, positioned anywhere within the Lazer Zone, the Millimeter GPS paver system’s machine control sensor is designed to compute the precise vertical information. There is no need for a moveable mast, the technology is designed to determine elevation automatically. Even if the site has an elevation variance of 10 meters (33 feet), there is no need to reposition the instrument or receivers with this technology. For sites with significant elevations or large areas, up to four LZ-T5 Lazer Zone transmitters can be linked to cover a larger area and elevation change of more than 130 feet. "Since we are free of stringlines, we like the efficiencies provided by the Millimeter GPS paver system," states Kevin Gehring, owner/operator at Gehring Construction & Ready Mix Co., Columbus, Neb. "We're not
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needing to wait and pay for surveyors to be scheduled and pound hubs in ground. And we're no longer waiting and paying employees to set stringline." Gehring believes he is also achieving better paving alignment and ride-ability because he is able to use actual radius data for horizontal and vertical curves instead of short tangent string line sections. Agreeing with Gehring's conclusions, Scott Murchison, P.E., LEED AP, and chief engineer for RC Construction, Greenwood, Miss. states, "We like the ease and flexibility that the system provides us, since we're no longer married to a stringline with all the time and effort required to get the slipform paver set up. We recently paved a new runway at Joint Base Andrews in Prince George's County, Maryland, for Air Force One. The 3,000foot long by 250-foot wide runway with two intersecting taxiways had a specified 7-inch per mile profilograph testing tolerance. With our Topcon system, we achieved an incredible profilograph
smoothness rating of less than 1-inch per mile. We couldn't be happier." The Topcon Millimeter GPS paver system appears to help with paving accuracy--both in material usage and concrete lay down. "Our yields have been much better than expected," says Jacob Headrick, paving/3D manager, GLF Construction Corp., Miami, Fla. "We're dialed into the exact amount of material we need, which saves on material costs and eliminates rework. "The accuracy with the Topcon Millimeter GPS system is phenomenal. We're achieving finished paved grade within a hundredth, and if you consider that a piece of aggregate can be bigger than that...that's pretty spectacular." Headrick also cites savings and return on his technology investment as benefits, "With our first project, we saved enough to cover the cost of the Topcon system. On our second job, we saved enough on outside survey costs to
purchase two Millimeter GPS systems if we wanted them." Certainly, technology is becoming integral to concrete paver's desire for the smooth, uniform surface of freshly-paved concrete they all seek. The Federal Highway Administration (FHA) has several ongoing programs that intend to ensure "that innovative technologies that can improve the safety and performance of the transportation system are deployed and implemented on the Nationâ€™s roadways." Clearly, one could expect that the technologies being adopted by concrete paving companies are consistent with the stated mission of the FHA and are directly contributing to the high-quality traveling experience highway users are expecting. Ed. Note: Jeff Winke is a business and construction writer based in Milwaukee, Wis. He can be reached via email at email@example.com.
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4/11/19 9:52 AM
SPECIFICATION GUIDE: SCREEDS
A compilation of technical information when choosing your next screed. Hand and Spin Screeds 1. THE EZ SCREED COMPLETE TOOL SET The EZ Screed Tool is designed for walks, driveways and slabs of various sizes. The EZ Screed Tool used in an upright position is faster and more effective in the leveling of concrete, resulting in a more precise, professional finish to your concrete job while minimizing stress on back and knees as in the traditional method of screeding. Features: Powder coated handle with stand, quality aluminum blades (3 to 7 lbs. each), lightweight and durable. ForConstructionPros.com/10080016 Model
EZ Screed Complete Set
5 lbs. per handle, 1 lb. per foot for aluminum screeds
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2. EZYSCREED WITH INBUILT LEVEL EZYSCREED is a manual screed, featuring an inbuilt level and reversible capabilities. It is lightweight with a designed screeding edge and reinforcements, making it the most useful, economical and strongest screed on the market. Available in lengths from 0.9 m / 2’11” to 3.6 m / 11’9”. ForConstructionPros.com/12003790
3. SPIN SCREED RUGGED SCREED The Rugged Spin Screed Weighs less than 100 lbs with 22’ pipe and screed Pipe lengths up to 22’ • T-handles The electric powered Rugged Spin Screed is lightweight, quiet; simple to clean, and make rapid length changes. It works on both flat surfaces and steep slopes. The Spin Screed can be used with concrete having a 3” slump and still produce a high quality durable surface. With the Spin Screed, you’ll produce flatter concrete surfaces with less work and time. • •
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30 Concrete Contractor | April/May 2019 | www.forconstructionpros.com/concrete
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SPECIFICATION GUIDE: SCREEDS
Wet Screeds 1. MBW SCREEDEMON The MBW ScreeDemon employs a simple, durable, low cost rubber isolator to drive the eccentric. The back-to-back triangular construction of the ScreeDemon bar is extremely rigid and minimizes variability in the transmission of vibration. The ScreeDemon simply clamps to the specially designed bar. The ScreeDemon’s patented mount retention method enables use of low durometer isolators without loss of operator control. Hand/arm vibration is 50 to 90% lower than competitive screeds. ForConstructionPros.com/10083973 Model
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5’, 8’ and 10’
3. SOMERO COPPERHEAD XD 3.0 This self-propelled 4th generation walk-behind Laser Screed® model automatically cuts concrete to finish grade, screeds it flat, vibrates it smooth, in a single pass. Superior productivity, increases labor savings, levelness, and return on investment. Applications: Slab-on-Grade, Slab-on-Deck, chaired rebar or mesh, in-floor heat, freezer slabs and ice rinks, including many NHL rinks. Winner of numerous Golden Trowel® awards. ForConstructionPros.com/11151571 Model
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4. MULTIVIBE MVPR100H Joe Lindley, owner of Jlin Corp. DBA Multivibe has an impressive background in the art of working with concrete. He had 20 years of experience as a contractor prior to his 26 years of design/ building equipment for concrete placement. Listening to customers is why Multivibe has the largest selection. All of the company’s products are designed and built with the Multivibe quality on focus. ForConstructionPros.com/12189542 Model
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32 Concrete Contractor | April/May 2019 | www.forconstructionpros.com/concrete
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*For complete details, check with your local Cat dealer. Financing offer valid from February 1, 2019 to June 30, 2019 on select models of new machines manufactured by Caterpillar Inc. Building Construction Products Division only (backhoe loaders, small dozers, small wheel loaders and telehandlers). Offers do not apply to Cat Utility Vehicles. To be eligible, a sales contract must be signed during the offer period. Offer available only at participating Cat dealers. Offer is available to customers in the USA and Canada only and cannot be combined with any other offers. Prior purchases do not qualify. Offer subject to machine availability. To receive the financing offer, all balances must be financed through Cat Financial, subject to credit approval through Cat Financial. Financing rate is subject to approval and not all buyers will qualify. Higher rates apply for buyers with lower credit ratings. Final machine prices are subject to change. Payments are based on an installment sales contract with 48 monthly payments and $0 down. Payment amounts are based on specific machine model and configuration. Payments may vary. Payments do not include taxes, freight, set-up, delivery, document fees, inspections, additional options or attachments. Offer is subject to change without prior notice and additional terms and conditions may apply. This offer has no cash value and is not transferable. Machines sold in Canada by authorized dealers are priced in Canadian dollars and the sale price and offer may take into account the exchange rate of Canadian dollars to U.S. dollars. © 2019 Caterpillar. All Rights Reserved. CAT, CATERPILLAR, LET’S DO THE WORK, their respective logos, “Caterpillar Yellow”, the “Power Edge” and Cat “Modern Hex” trade dress as well as corporate and product identity used herein, are trademarks of Caterpillar and may not be used without permission. www.cat.com / www.caterpillar.com
4/11/19 10:36 AM
SPECIFICATION GUIDE: SCREEDS
Wet Screeds Continued
5. MQ WHITEMAN DUOSCREED Multiquip’s DuoScreed utilizes a unique blade profile that enables one person to strike-off concrete floors. The screed’s vibratory action embeds aggregate and reduces air voids, producing a strong, dense slab, while eliminating the strenuous time-consuming labor of manual screeding. Unlike competitive designs (which require different blades for each application) the DuoScreed uses a unique reversing blade that allows for the usage of either the curved form to form edge or the wet-screeding edge. ForConstructionPros.com/10079949
6’, 8’, 10’, 12’, 14’, 16’
.67 U.S. qt.
6. WACKER NEUSON WET SCREED NOW AVAILABLE WITH MAGNESIUM BOARDS Wacker Neuson’s wet screed is now available with a full line of magnesium boards. Magnesium is a strong, lightweight metal that will reduce the weight of the boards by over 25 percent compared to aluminum boards. The full line of magnesium boards is available in seven different lengths: 6’, 8’, 10’, 12’, 14’, 16’ and a 2-meter option. All the magnesium boards have a 4.9” width and range in weight from 9.8 lbs. to 25 lbs.. The boards are easily connected to the wet screed system. ForConstructionPros.com/12058112
P35A Wet Screed
4’ to 16’
Power Screeds 1. SOMERO S22 EZ LASER SCREED® The Industry’s Best! Proof - for 2017 the S-22 won 3 Golden Trowel Awards and set a world record for the levelest floors in the world! Also industry leading production rates, unsurpassed power, features, and maneuverability. New features include: EZ Clean Head, compartment layout, convenience items, improved ergonomics. With so many exclusives, the S-22EZ options platform allows you to build the machine the way you want to meet your needs. ForConstructionPros.com/20999415
Engine/Motor (Mfg & Horsepower
# of Drive Wheels
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Machine: 7’ 2” Head width: 14’ 7” or 16’ 6” Vibrator width: 12’ or 14’
240 or 280 sq. ft.
Cummins Turbo, Tier 4 Final 65 hp
4 drive wheels Steering: 2/4/ Crab
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Power Screeds Continued
2. LIGCHINE INTERNATIONAL SCREEDSAVER BOSS 240 Ligchine International’s newest screed is the ScreedSaver MAX PRO. The MAX PRO combines the classic durability and accuracy of the ScreedSaver MAX with the technology advancements and design from the top-of-the-line ScreedSaver BOSS 240. The MAX PRO comes equipped with a touchscreen diagnostic display, zero turn drive system for unrivaled machine navigation, and concrete additive screed head spray system. Boom extension of 16’ (4.9m) with a 12’6” (3.8m) screed head results in screed rates up to 7,000 sq.ft./hour (650m2) ForConstructionPros.com/12321849 Model
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Engine/Motor (Mfg & Horsepower
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Kubota 24.8 hp (Tier 4 Final)
3. BATT SCREED FROM CURB ROLLER MANUFACTURING According to the company, the Batt Screed is the world’s first battery powered roller screed which not only eliminates exhaust fumes, power cords, and hydraulic power sources, but is designed for quick assembly and break down. The removable ends can be installed quickly in tubes from 3 ft. to 22 ft. long, and the single pin connection allows for easy transport. Powered by DeWalt FLEXVOLT, the Batt Screed offers unparalleled mobility, precision, and efficiency to contractors of all sizes. ForConstructionPros.com/21062140 Model
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“Drill It BackSaver Better!”
www.forconstructionpros.com/concrete | April/May 2019 | Concrete Contractor 35
4/12/19 8:45 AM
By Jeremy Wishart
Benefits to Using Propane for Concrete Construction Equipment How the alternative fuel can help reduce costs and emissions for concrete contractors.
oncrete can be both the foundation and the finishing touch on a construction project. It’s why concrete construction often requires a lot of flexibility on sites when it comes to working around weather, utility connections, and other contractors working on different aspects of a project. And this is where propanepowered concrete construction equipment can stand out compared to other fuel and power sources. Propane has been used for decades as a reliable, widely-available fuel. It can fuel jobsite lighting and space heating, helping to safely extend work days beyond daylight hours and provide the right temperatures and moisture levels no matter the season. The fuel is also frequently used for power generation on sites lacking utilities. More recently, propane has also been found powering all manners of concrete equipment, including power trowels, power buggies, saws, and concrete finishing equipment such as grinders, polishers, and floor strippers. In fact, more brands that were once electric-only are now offering enginedriven solutions powered by propane. This is in addition to the trend over the past couple years of manufacturers exploring options beyond diesel in heavy duty applications, as well. There
are a few reasons why brands and contractors continue to turn to propane for concrete construction: the fuel’s lower price per gallon, its versatility, and its low emissions.
PROPANE HAS A LOW PRICE PER GALLON Concrete contractors have likely enjoyed low prices throughout the first quarter of 2019 for gasoline and diesel, but the high gasoline prices of last summer and prior years has left a lasting memory with many in the industry. And even now, forecasts are calling for gas prices to approach $3 per gallon at the height of the summer work season again. However, by considering propane equipment, contractors have another option for fueling equipment that can provide a long-term solution to the price fluctuations of traditional fuels. For starters, propane is a product of both natural gas and petroleum, and the price for propane falls between the price of those two fuels. Additionally, the majority of the propane supply used in the United States is produced in North
On long-term jobsites, propane cylinders can be stored in secure, locked cages. Photo Credit: Propane Education & Research Council
America, providing cost stability even when the global fuel markets fluctuate. Because of these factors, propane is consistently less expensive than gasoline and diesel. Contractors who commit to using propane equipment can further protect themselves from market fluctuations by entering into a fuel contract with a local propane supplier. The fuel contract can provide an advantage in forecasting annual costs by locking in a set price per gallon for both short-term and longterm fuel needs.
PROPANE IS VERSATILE AND PORTABLE Propane allows contractors to cut the cord tying them to the electrical grid, a benefit on sites that aren’t yet connected to utilities or are located off the grid entirely — a growing possibility as green construction trends gain traction.
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Removing the restrictions of cords also gives contractors more freedom of movement when it comes to grinding and polishing work on large open spaces. With propane, there are no concerns of working beyond the reach of a power cord, allowing work to be done faster as employees no longer have to operate with finding the next outlet or compatible power supply in mind. Using propane-powered concrete finishing equipment in well-ventilated rooms can also reduce trip hazards from electrical cables while other jobs are completed. Additionally, propane cylinders used for construction equipment are able to be safely transported to jobsites on trucks or trailers with equipment. On long-term jobsites, propane cylinders can even be stored in secure, locked cages. And by setting up a cylinder exchange program with a propane supplier, contractors can ensure that fuel is always available without the hassle
of refilling gasoline or diesel tanks at a filling station. Speaking with a local propane supplier can help contractors find the best refueling solution, as well, which is as easy as using the Find a Propane Supplier tool available online from the Propane Education & Research Council.
PROPANE IS A CLEAN FUEL Compared to gasoline and diesel equipment, propane produces fewer emissions. This includes carbon monoxide emissions, as well as greenhouse gas emissions such as nitrous oxide (NOx) and sulfur oxide (SOx). For contractors working on sites requiring reduced emissions, the availability of propane equipment can be a selling point for customers. With proper ventilation, propaneâ€™s emissions profile enables the fuel to be used both indoors and outside, as well, which can
mean huge gains for crew productivity, particularly when moving materials around a site with a power buggy or forklift. The fuel is also recognized by the EPA as a non-contaminant of soil, water, and air â€” another fact that contractors can call out when working with greenminded customers. Whether a concrete contractor is looking for a solution to fuel cost fluctuations, or to meet the needs of a tricky project, propane can offer a lower price per gallon, usage versatility, and reduced emissions to help land bids and turn profits. For more information on propane, visit propane.com/propane-products/construction-equipment. Ed. Note: Jeremy Wishart is the director of off-road business development at the Propane Education & Research Council. He can be reached at firstname.lastname@example.org.
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www.forconstructionpros.com/concrete | April/May 2019 | Concrete Contractor 37
4/23/19 9:05 AM
By James R. Baty II
To “Air” is Human, to Forgive is Divine For 2019, my technical column will continue to offer insight to industry issues stemming from contractors facing technical and safety challenges.
uestion: It has come to my attention that the concrete contractor working on my new home used concrete that was air-entrained for the basement and garage slabs. The research I’ve done suggests this is bad. Is it true or false?
and contractor should always be consulted in combination with the research and it never hurts to go directly to sources like the Concrete Foundations Association, American Concrete Institute and the American Society of Concrete Contractors for technical documents providing further qualified support.
NSWER: Research via the Internet can open a mix of challenges, no matter the subject matter of the inquiry. You can literally find opinions and research to support any angle and much of it is based on the way you ask the question as well as not being thorough in qualifying sources. The issue of air-entrainment continues to be one of the fastest growing technical concerns found in the concrete industry. This is due to concrete codes having generic exposure class requirements that are more often misunderstood and over-analyzed to be conservative. A reputable craftsman, producer
Whether considering ACI 3181 or ACI 3322, classes have been assigned to concrete situations based on the severity of exposure to freezing temperatures and the likelihood of being in a saturated condition. The combination of the two determine the specification or requirement for the use of air-entrainment to use. Table 5.2.1 of ACI 332-14 establishes descriptions for the four classes of the category RF, which stands for resistance to freezing as follows: The additive conditions of this table help the user/specifier determine where the concrete is to be placed in relationship to the exposure of the two primary conditions,
freeze-thaw cycles and saturation. Notice there isn’t a consideration for just saturation for the RF category. The code then provides a suggested table for a project where the exposure classes can be selected for each category. This is a commentary table that can be added to a specification document or in general notes in a drawing set and appears as follows: In applying the code to this discussion, it should be clear to the user that the basement slab and an interior slab will be classified the same and a garage slab would be considered an interior slab unless it was unheated and exposed to weather. Since after further inquiry it was determined that the garage floor was protected by a garage door, despite it not being heated, the exposure is not severe enough to separate it as a driveway. In reviewing the first table for class Table 5.2.1 of ACI 332-14 establishes descriptions for the four classes of the category RF, which stands for resistance to freezing. Photo Credit: American Concrete Institute
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severity, RF0 would be assigned automatically to a basement slab since it has no exposure to freezing and thawing cycles. The garage slab now must be determined whether it is has the potential to be in a saturated condition “while” exposed to freezethaw cycles. Given that garage slab nearly always receives a hard-troweled surface, that which has been set with a machine that burnishes the surface, the porosity has been eliminated and saturation is not possible. Although deicing salts will likely be carried into the garage, these will sit on the surface of the slab while the water evaporates or dries. It might be difficult to assign an RF0 class to the garage due to it being an unheated floor and the presence of moisture and even deicing salts then offers either an RF1 or RF3 class. To move the discussion along, the RF0 class requires no air-entrainment according to ACI 332-14 and both the RF1 and RF3 classes have air-entrainment requirements based on the maximum aggregate size. However, what this table does not account for is the hardtroweled surface and the barrier to absorption it provides. Furthermore, the code does not address the impact of air-entrainment conflicting with the finishing process.
TECHNICAL RESOURCES One of the important document references to understand the importance of considering the finishing characteristics impacting air-entrainment is ASCC Position Statement #13. This document has
purposed direction to the contractor or the specifier explaining the risks associated with selecting airentrainment exposure classes for such slabs. These risks include: • Risk of concrete scaling and possible repair cost due to coldweather exposure. • Cost of air-entrained versus nonair entrained concrete. • Increased risk of delamination and blistering, and possible repair cost when the surface is machine troweled. • Reduction in surface air content and change in hardened air void parameters when the surface is machine troweled. The presence of air-entrainment when slabs are to be finished creates a conflict between the intended durability and the resulting durability. This document brings two additional references to light for important direction in considering the exposure versus the performance: • The optional requirements checklist of ACI 3014 states that intentionally entrained air should not be incorporated in normal weight concrete slabs that require a dense, polished, machine-troweled surface. • ACI 302.1R5 states that entrained air is not recommended for concrete to be given a smooth, dense, hard-troweled finish. The document concludes that the position of the contractor should be to only hard-trowel air-entrained concrete if: a) required by the specification (which comes from a code
The code then provides a suggested table for a project where the exposure classes can be selected for each category. This is a commentary table that can be added to a specification document or in general notes in a drawing set. Photo Credit: American Concrete Institute
interpretation)…and…only with the acknowledgement by the owner or representative of the risks and that the specifier is to bear the responsibility.
CONCLUSION Quality concrete is, or should be, desired by everyone in the process of new construction. It should not be surprising that professional contractors and ready mix producers want the installation to perform the very best. It is understood that the designer/specifier expects concrete to achieve and maintain the aesthetic and performance for the project. It is also undeniable that the owner anticipates their investment to achieve a lasting quality for their investment. Therefore, the success must be predicated on communication for the intent, means and methods and options to pursue in order to achieve satisfaction for all three of these interests. The use of air-entrainment should be carefully considered and monitored for the actual conditions of both construction and exposure to establish appropriateness. It should not be used as a conservative measure for the protection of the unknown.
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CFA is committed to creating greater awareness and better education on the technical aspects of the concrete industry. Rather than making assumptions on detailing or relying on the concrete producer alone to make decisions for sufficient concrete design, contractors need to recognize the resources available to them and spend enough time to understand them. This is a primary reason for the creation of the ACI/CFA Residential Foundation Technician Certification, to demonstrate and verify command of these technical resources for use in projects. This certification is also the first step toward the ability of a company to achieve CFA Certified Foundation Company status.
Concrete Institute, 38800 Country Club Drive, Farmington Hills, MI 48331 | Phone: 248-848-3700 | www.concrete.org 3. Hard Trowel Finish on Air-entrained concrete (Position Statement #1) published by the American Society of Concrete Contractors, 2025 S. Brentwood Blvd, Suite 105, St. Louis, MO 63144 | Phone: 314-9620210 | www.ascconline.org 4. Specification for Structural Concrete (ACI 301-16) published by the American Concrete Institute, 38800 Country Club Drive, Farmington Hills, MI 48331 | Phone: 248-848-3700 | www.concrete.org
5 Guide to Concrete Floor and Slab Construction (ACI 302R-15) published by the American Concrete Institute, 38800 Country Club Drive, Farmington Hills, MI 48331 | Phone: 248-848-3700 | www.concrete.org
NEWEST ADDITION TO THE K 520 SERIES OF POLISHABLE TOPPINGS!
Jim Baty is the Executive Director for the Concrete Foundations Association after having served as Technical Director since 2001. He is currently chair of ACI 332 and a voting member for ACI 306 with priorities of establishing better guidance and structure for residential concrete construction. For more information on this topic, contact Jim Baty at email@example.com. Find out more at www.cfawalls.org. The CFA is a national association for professionals with the mission to support the cast-in-place contractor as the voice and recognized authority for the residential concrete industry. ACI 332 is the Residential Concrete committee for the American Concrete Institute and as a code committee is seeking professionals from all aspects of this industry with an interest in participating in the development of expanding and strengthening this concrete code.
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1. Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary published by the American Concrete Institute, 38800 Country Club Drive, Farmington Hills, MI 48331 | Phone: 248-848-3700 | www.concrete.org 2. Residential Code Requirements for Structural Concrete (ACI 332-14) and Commentary published by the American
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Preparation is the Key to Polished Overlays
Industrial Caulk and Seal Inc.
In the world of concrete overlays… it’s what lies beneath that matters most. by CT “Chip” Marshall
en Franklin is credited with the adage… “By failing to prepare, you are preparing to fail.” This has never been more evident than in the world of polished overlays specifically and all floor coatings in general. Polishable concrete overlays represent the pinnacle in comprehensive floor repair and stand on the cutting edge of the polished concrete industry. Ongoing advancements in polishable overlayments have continued to turn weathered
and beaten concrete floors into beautiful finished floor surfaces. However, if the end goal is a fantastic finished product it had better start at the very beginning. Polishable concrete overlayments are generally not considered for great existing floors which means that an existing floor surface is probably full of residual damage as a result of its former use. Floors being considered are often pocked with holes and cracks. They may have existing flash patching from previous floor coverings. They may have or have had ceramic tile or VCT or layers of one or the other. All in all, the existing floors being considered for polished overlays are in rough shape. All polishable concrete overlayments start with epoxy. The epoxy serves as a primer for the concrete overlay. As an epoxy floor is the first step to a successful overlay, it’s best to remember that standard industry guidelines to epoxy placement are no less critical in polishable overlayments than in traditional epoxy flooring. CTS’s Rapid Set TXP Fast is one such epoxy primer, and the TXP line is a fantastic starting point. Rapid Set TXP Fast is a fast setting two component alkali resistant epoxy primer which is the initial building-block for CTS’s Rapid Set Tru PC (Polished Concrete). The technical data for TXP Fast clearly stipulates standard industry guidelines related to epoxies…”TXP FAST is used on properly prepared concrete. Surface must be dry, porous, clean, sound, and free of grease, oil, curing compounds, dust, mastic and other contaminants or bond breakers.” Every
epoxy manufacturer states some variation of this standard language related to proper epoxy placement. The term “sound” is a catch all in the epoxy world, but that catch all is critical. Sound concrete needs to be free of cracks, spalling, delamination, scaling and blisters. For the surface to be sound, all previous flash patching or sealers need to be completely removed. Additionally, spalls or cracks need to be properly repaired. Another looming item in the epoxy world deals with moisture transmission through concrete floor slabs. Even existing concrete can still suffer from moisture permeating from underneath and through the concrete. If moisture is permeating through the slab that moisture may result in epoxy failure as the moisture collects between the epoxy and the concrete. Moisture transmission is measured through Moisture vapor emission rates (MVER) and categorized under ASTM F1869. Traditionally most epoxy primers call for acceptable substrates to have an MVER less than or equal to 10 lbs./1000 sq. ft per 24 hours and relative humidity less than or equal to 100%. There are hundreds of independent testing agencies which can test the MVER on a given surface. This is a critical step in floor preparation and should not be overlooked. Most epoxy manufacturers require an abraded floor surface prior to epoxy installation. Abrading the floor surface can be accomplished through either shot blasting or properly tooled concrete grinders. This process results in huge variations in
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Industrial Caulk and Seal Inc.
the concrete floor surface, and these variations or peaks and valleys allow the epoxy to grip the existing concrete. Mechanical abrasion may also be critical in achieving a “sound” substrate as well. The International Concrete Repair Institute led the charge in standardizing abraded surfaces through the development of the CSP, or Concrete Surface Profile, scale. The CSP scale ranges from a one (very smooth) to a nine (extremely rough), and most floor coverings will call out the scale in their technical data or bulletins. CTS’s Rapid Set TXP Fast specifically calls for a 3-5 on the CSP scale in order to achieve proper adhesion. ICRI does sell a series of chip samples for the CSP scale through their website. The chips are indispensable in abrading concrete floor surfaces when the feel of the surface profile is critical to success.
In order to reach the required CSP of 3-5 mechanical means are necessary. “Mechanical means” means specialized equipment. Acid etching the floor surface should not be considered a viable means in creating the required concrete surface profile. Traditional shot blasting equipment has always been the gold standard in achieving deep surface profiles and is more than adequate to achieve the required 3-5 CSP. However, planetary head grinders are also adequate if
tooled aggressively. Diamond tooling manufacturers have created dozens of variations of removal and/or profiling tooling in recent years. This is critical for the contractor as it minimizes the total equipment required on site to achieve a finished product. The SASE company recently released Bush Hammer tooling for planetary head grinders. The tooling plate mounts to standard grinding equipment and hosts hundreds of tungsten pins which abrade the floor surface.
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Industrial Caulk and Seal Inc.
back-roll as established above. The sand creates a bonding agent for the concrete overlayment to follow. The sand broadcast should use clean, dry silica sand and technical data for the epoxy primer should always stipulate that the sand broadcast is to the point of rejection. Rejection should mean exactly that. Sand should be broadcast into the epoxy until it is dry on the surface. The epoxy literally rejects additional sand. #20 or #30 mesh dry, silica sand is adequate for sufficient
bonding of the concrete overlayment. Following the applicable cure time of the epoxy primer, excess sand should be vacuumed from the surface and the resulting surface should be a beach. Concrete overlayments are taking the world by storm, but correct preparation is imperative to a finished floor surface. All these steps are critical to the long-term success of any concrete overlayment. If a polished concrete overlay is to be a quality alternative in redeeming aging concrete floor slabs, it’s best to remember and abide by Ben Franklin’s words… “By failing to prepare, you are preparing to fail.”
Ed. Note: C.T. “Chip” Marshall is the executive vice president of Industrial Caulk and Seal Inc. Chip can be reached through their website www.industrialcaulkandseal.com.
Proper tolling of this type will create a 4-5 CSP and is rapidly becoming the go-to for knowledgeable contractors. Once the MVER test is complete, spalls and surface imperfections have been repaired, and the surface has been adequately abraded it’s time for the epoxy primer. A single coat of epoxy primer is generally recommended; however, each case may differ and it’s best to work within the confines of the manufacturer’s instructions. Traditionally epoxy primer will rely on a single coat at a thickness of 10-12 mils through a standard squeegee and back-roll application. The back-roll process should be perpendicular to the squeegee process and should require the use of a ½” nap roller. As a primer for concrete overlayments the next step is crucial and requires a sand broadcast into the epoxy immediately following the
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www.forconstructionpros.com/concrete | April/May 2019 | Concrete Contractor 45
4/11/19 10:00 AM
Beat the Grind with a Pre-separator A pre-separator can improve extractor’s performance, giving you longer run times and more. by Michelle Kelley
rinding concrete will do a number on your gear. It’s the nature of the beast. One of the most frustrating aspects of project management can be unexpected hiccups with your dust extraction equipment. This is especially true now that you’re required to comply with the OSHA silica dust standard. There’s nothing worse than having a goal time thwarted because your extractor is constantly losing suction power. Believe it or not, there’s a way to avoid this time sucking situation. Enter the pre-separator—a simple accessory that can improve extractor’s performance, giving you longer run times and better chances of staying on schedule.
HOW DOES IT WORK Just like the name implies, a pre-separator hooks up to your extractor and separates a majority— from 80-97%—of incoming concrete dust into an attached waste container. As a result, only a small percentage of material passes via the airstream to your extractor and its filter. Without a pre-separator, a dust extractor’s suction power begins to rapidly decline within a few minutes, as its filter is exposed to more and
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more material. By adding a pre-separator, the filter clogging process is significantly slowed, allowing for more consistent airflow over longer periods of time. The cleaner your filter stays, the longer your extractor can operate at peak efficiency. Faster cleanup can be a game changer for project completion times. Equally appealing is the cost savings. Dust extractor filters can be expensive to replace. By prolonging filter life, a pre-separator can pay for itself in a few short weeks. Another advantage of using a pre-separator—one that is often overlooked—is increased waste capacity. You’re no longer limited to what your extractor can hold. Depending on the size of the container it’s paired with, a pre-separator can easily multiply the amount of material you’re able to collect at one time.
a lot of contractors, it often comes down to the size of the job. If you deal with large volumes of material, you may want to opt for a 55 gallon steel drum over a Longopac compatible unit. A pre-separator’s ease of mobility should be considered as well. If you’re a one person operation, a steel drum without a dolly may not
be the best choice. Many Longopac units, like Oneida Air’s CDD-L PreSeparator (available at oneida-air. com), are sold with a wheeled cart, allowing you to easily roll your way through a worksite. If you’re leaning towards a mobility cart, make sure it’s equipped with locking casters. You don’t want to waste your time chasing a piece of equipment.
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CHOOSING A PRE-SEPARATOR There are several different factors contractors should consider before choosing a pre-separator, such as design, containment options, and mobility. A cyclone is the most efficient type of pre-separator. Its conical design uses centrifugal force to spin debris out of the airstream and down to the waste container below. As a result, only a small portion of material rises through the “eye” of the cyclone and out to the extractor. If you want to achieve the highest percentage of pre-separation possible, a cyclone is your best bet. If equipment height is a concern, you may want to consider a pre-separator head, which has a much lower profile and usually consists of an inlet and outlet stacked atop a flat disc. Unfortunately, the squat form of these types of pre-separators make them less efficient than cyclones; so you’ll notice more material passing through to your extractor. Another consideration should be the type and capacity of the waste container you’ll be using with the pre-separator. The market offers a variety of choices from Longopac bags to your typical steel drum. For
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KNOW YOUR HOSE When it comes to grinding concrete, all hoses are not created equal. Working with the wrong hose is a serious risk to contractor safety, as it increases risk of electric shock. As material moves through a hose, it creates a positive charge. The charge continues to build up until it is released, which is the moment a shock occurs. This is much, much more severe than the shock one might experience from touching a metal door knob or walking on carpet. Such a shock can cause serious burns and even cardiac arrest. It is for this reason that static dissipative or conductive hose is strongly recommend for use with any equipment attached to a grinder, including extractors and pre-separators. It’s also important to be mindful of hose length. When using a
pre-separator, the general rule of thumb for hoses is the shorter, the better. It’s less restrictive on airflow. Ideally, you want no more than five to six feet of hose between the extractor and pre-separator. A few extra feet of hose will not have a noticeable effect on suction performance. It’s when you add 10 or 20 feet that you start to notice a difference. Sharp bends in hose should also be avoided, as they impede airflow and suction.
TROUBLESHOOTING While a pre-separator can be quite the work horse for such a simple accessory, there are few common issues contractors may encounter. Perhaps the most common experience is a sudden loss of suction. This is often caused by an air leak or decrease in preseparation efficiency, which can
occur anywhere in your setup, from a pinhole in a hose, to an improper seal between the pre-separator and its base. The simplest way to search out the leak is to perform a smoke test (kits are available at most hardware stores) while the extractor is running. A clogged filter on your extractor or a hose blockage will also impact suction strength. Cleaning or replacing your filter and clearing your hose of debris are sure fire ways to correct this issue. If you want to increase the efficiency of your dust extractor and improve project times, adding a pre-separator is an quick and easy way to beat the grind. Ed. Note: Michelle Kelley is Advertising and PR Manager for Oneida Air Systems.
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INDEX ADVERTISER............................... PAGE Aaron Hilbert LLC................................................................28 American Concrete Institute.................................................7 Ardex....................................................................................41 BackSaver.............................................................................35 Bloom Manufacturing Inc....................................................28 BORIDE Engineered Abrasives..........................................47 Brickform, A Div. of Solomon Colors, Inc..........................17 Brokk Inc.................................................................................9 Caterpillar Dealer Network*...............................................33 Collomix USA.......................................................................18 Curb Roller Mfg. LLC...........................................................49 Diteq Corp...........................................................................24 Euclid Chemical Company..................................................44 EZ Screed Tools...................................................................48 Gomaco Corporation............................................................5 Jlin Corp...............................................................................39 Kingdom Products.........................................................19, 29 Kraft Tool Co........................................................................49 Ligchine International Corp................................................15 Lura Enterprises, Inc............................................................51 Max USA Corp.....................................................................22 Mecom..................................................................................37 Metzger/ McGuire...............................................................49 Minnich Manufacturing.......................................................11 Multiquip..............................................................................52 Nox Crete Products Group.................................................23 Oneida Air Systems.............................................................43 The Quikrete Companies....................................................21 Reef Industries, Inc..............................................................16 Schwing America Inc...........................................................31 Simpson Strong-Tie Co., Inc.................................................2 Solomon Colors...................................................................44 Somero Enterprises.............................................................27 Superabrasive Inc................................................................45 Trinic......................................................................................48 W.R. Meadows, Inc..............................................................25 * Denotes regional advertiser
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www.forconstructionpros.com/concrete | April/May 2019 | Concrete Contractor 49
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THE LAST PLACEMENT
By Brad Humphrey
Steps to a Successful FIRST DAY
nce a new employee is hired and placed on a crew, nothing is more critical than how the foreman or crew leader handles the new worker on their first day. Here are seven actions a foreman or crew leader should take on that new employee’s first day – both to make the employee more comfortable and to give the leader a chance to begin the assessment process. 1. Shake hands & introduce the crew. Shaking hands hints at the new employee’s self-confidence, provides insights (based on grip strength) if the worker has the physical strength to perform some of the on-the-job tasks, and can signal the employee’s level of enthusiasm (which can be reinforced – or not – by their eye contact and response to the handshake. Then introduce the new employee to the rest of the crew, making sure to introduce each member by name. While the new employee is not expected to memorize the names each employee, this effort serves as an “ice breaker,” allowing the crew to feel more comfortable with the new face. 2. Match the new employee with another crew member. For a successful first impression and a quick study of the new employee, match the new worker with one of your existing crew members. Matching new employees with a current worker will reduce some of their anxiousness, allowing them to relax so they can focus more on what they see, hear, and learn. Matching a crew member with the new employee also provides some field assessment from a trusted worker. Over the course of a few days, the veteran
worker will be able to discern the new employee’s work habits and describe the new employee’s attitude, work strengths, work attitudes etc. 3. Assign easier but necessary tasks. If the new employee comes to you as an experienced worker, you might be able to start them out on more complex work. But if you have a new employee with little to no construction experience, especially in your area of specialty, then introduce them to some of the easier, more fundamental tasks. As much as you want that new employee to fill a huge need in the crew, you will only frustrate them if they are pressed too soon to perform difficult tasks; you’ll risk either a “No Show” the next day or your crew’s anger – or both. Make the new employee’s first day as simple or as easy as possible. After all, if they cannot learn, or if they struggle to perform even the simplest of tasks, how difficult will it be to push them to learn more complicated tasks and processes? 4. Check on the new employee at “10 & 2”. That’s 10:00 a.m. and 2:00 p.m.! Most new workers will be glad to have an early morning visit from their Foreman – just ask how they’re doing, if they have any questions, and if they’re ready for another task! Use the afternoon check-in to ask what they have learned on their first day. Answers to such simple questions can tell you loads on how they have embraced and internalized their work day. 5. Take the time to explain the “why". It’s easy to teach a worker the “What” or even the “How” to do something. But explaining “Why we do it this way” begins the process of education and defines how our company is different from others. You will have to repeat the “Why”
periodically but sharing it early, here, begins the process of letting the new employee know that there is a real and significant purpose to what they will be doing today, this week – and maybe for their career. 6. Ask the worker what they learned on their first day. Ask them not only how they thought their first day went, but what did they actually learn. Make sure to give them a heads-up early in the day so they can have time to prepare their message. The new worker who is enthused and wants to work for your company will respond positively to this question. The worker who sort of “hems and haws” may not be nearly so interested in working for your company. 7. Tell the new worker What they did right & well before leaving for the day. For our new employee, simply telling them how you observed their work effort can ignite a flame of enthusiasm in the employee. Be sure to do this just before they leave for the night. It will be a positive send off, one that they will transfer to those waiting for them at home. With the number of workers looking to construction as a career choice dropping, contractors must pull out all of the stops to give a new worker every excuse possible to stay with their new contractor. Incorporating these seven steps into your hiring and on-boarding process will help your new hire become more comfortable more quickly and will enable you to more easily evaluate whether this new hire could be a longterm employee. Brad’s newest publication, “A Foreman’s Playbook for Leading the New Employee,” is available through Amazon and his website, www.pinnacledr.com.
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In order to GROW a business, you need to become as versatile as possible, so you can bid on a wide range of projects. This means that when it comes to concrete placement, the screed system you choose, must be able to take on any project imaginable. If your screed can’t take on every pour out there, “you have the wrong screed”. No other screed on the market today offers all the versatility that the Lura screed system can. See for yourself and, “Compromise Somewhere Else”.
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4/11/19 10:08 AM
4/11/19 10:08 AM
Concrete Contractor delivers original content to help concrete contractors build their projects and run their businesses more efficiently an...
Published on Apr 23, 2019
Concrete Contractor delivers original content to help concrete contractors build their projects and run their businesses more efficiently an...