Concrete Products

JUL 2019

Concrete Products covers the issues that attract producers of ready mixed and manufactured concrete focusing on equipment and material technology, market development and management topics.

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40 • July 2019 www.concreteproducts.com COVER STORY BY DON MARSH Visitors to the new warehouse of helical pile and rebar accessory manufacturer Foundation Technol- ogies Inc. don't need to look down to see concrete floor slab finesse: A glance up the facility's inte- rior tilt-up walls evidences a smooth, flat and extremely hard 348- x 130-ft. casting surface. Built adjacent to the manufacturer's Law- renceville, Ga., home office, the warehouse harbors one of the largest slabs on grade—free of saw-cut control joints and expansive cement specs—to date. The 45,000-sq.-ft. facility and companion 12,000-sq.-ft. loading dock pavement mark commercial launch of the Megaslab Joint- less Concrete System from Sinclair Construction Group, Marietta, Ga. The foundation, pavement and wall contractor credits the proprietary sys- tem's performance in large commercial projects to groundbreaking concrete technology; premium admixtures and fibers; plus, finishing methods that net dense, impermeable slabs. An absence of saw-cut control joints in the Megaslab tem- plate eliminates the prospects for spalling and perimeter curling common in conventional, main- tenance-prone concrete slabs on grade. "This a complete system of base preparation, mix design, slab engineering and finishing," says Sinclair CEO Jason Adams. "Megaslab has a very broad market potential considering the function of large slab on grade facilities, whose owners place a premium on low maintenance floors. As we have demonstrated on our first commer- cial installation of scale, Megaslab is even more unique among slabs promoted as 'jointless' due to its suitability for tilt-up concrete." He cites a low maintenance, joint-optimized slab's value proposition for a variety of commer- cial or industrial facilities. In a typical warehouse, forklift tire traffic compromises joint integrity and spawns routine floor patching and repairs. In a food processing and packaging facility, on the other hand, sanitation is paramount; floor joint elimi- nation reduces bacteria-supporting areas plus dust contamination attending maintenance schedules. Conventional reinforced, jointed concrete slabs also limit rack and robotic configurations in advanced distribution or manufacturing facilities' automated storage and retrieval systems (ASRS). The Megaslab Jointless Concrete System sig- nature version is designed for purpose with 4-in. topping slabs up to 22-in. depth for ASRS instal- lations. The Megaslab EL (Elevated) version suits placement on metal decks plus elevated slabs with conventional rebar and post tensioning. Sinclair has begun promoting the value-added system for its own contract work and under licensing terms with peers who can demonstrate competence in precise slab placement and finishing methods, and source ready mixed concrete with requisite quality assurance and control. Measured against conventional concrete slab practice, Megaslab mixes and surface-hardening techniques yield a robust surface much less prone to dusting—a condition receiving greater scrutiny in light of crystalline silica exposure monitoring in work- places. The mix design is formulated to account for local material variety from coast to coast. In comparison to common conventional slab on grade mixes, it exhibits higher compressive, flex- ural and tensile strength properties. PILOT SITE CONDITIONS: CHALLENGING BY DESIGN Leading into Megaslab commercialization efforts this year, Sinclair placed a test section at the Warren CAT Lubbock repair shop. The West Texas Caterpillar dealer subjected the slab to an aggres- sive, 87,000-lb. load: A D8T dozer continually running on a zero radius turn pattern to test sur- face integrity. While the machine made removable scuff marks, it did not chip or spall the concrete. The Foundation Technologies site presented less aggressive surface, but more critical place- ment and site condition testing. A late-2018 schedule for the loading dock pavement enabled crews to measure concrete mix properties and finishing potential under less than optimal con- ditions. The larger warehouse slab placement three months later offered up similar damp, cool weather to prove mix design and placement adaptability. The latter slab has a single transverse con- struction joint dividing 182-ft. and 166-ft. sections, each 130-ft. wide. It uses Sinclair's optional Armor joint, shaped like a sine wave and formed with two pieces of 1/8-in. thick steel, 6 inches deep. The Armor joint wave pattern elim- inates the potential for slab damage associated with conventional straight joint cuts, which are subject to impact at 90-degree angles from wheels or attachments on forklifts or other industrial vehicles. During Concrete Products' mid-Spring visit to the Foundation Technologies warehouse, more than a month ahead of the standing seam metal roof installation, the Armor joint conveyed slab thermal mechanics by opening widest at points least exposed to the sun. Subsequently, Jason Adams recalls, "We found that the entire joint would open at night due to cooler temperatures— cooler than the 'memory' temperature when the concrete set the day it was placed. Then it would close during the day when exposed to the sun. And when it would close, we measured only 1/8 inch of actual shrinkage over 348 feet. So when the joint was open, it was all due to lower tem- perature and not shrinkage." Continued on page 42 JOINTLESS FEAT Megaslab developer Sinclair Construction subtracts saw cuts, adds value Jason Adams formed Sinclair Con- struction in 2012 as the Atlanta market showed strong signs of re- covery. It was a natural step after nearly 15 years with one major and one smaller general contractor. Sylvester Schmidt serves as Megas- lab head of Technology, bringing the new venture a wealth of insight on cement and admixture technolo- gy, along with concrete practice.

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