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.
Issue link: http://concrete.epubxp.com/i/849790
94 • July 2017 www.concreteproducts.com INNOVATIONS ADMIXTURES The Georgia Department of Transpor- tation approved the use of Premier Construction Products Group's PRE- Vent-C, a shrinkage-reducing and crack control admixture, among accelerated construction techniques on the Interstate 85 over Piedmont Road Bridges contract. Completed ahead of schedule, the six-week emergency project stemmed from a late-March fire that doomed twin structures carrying upwards of 250,000 vehicles daily. A fixture in Atlanta ready mixed production, Thomas Concrete added PREVent-C to bridge deck and bar- rier mixes to ensure an efficient construction timeline and low main- tenance, finished structure. The admixture was selected because it blends expansive components with pore water surface tension reduction to defend against cracks and increase a structure's projected service life. It has been proven to reduce concrete shrinkage by more than 90 percent, Premier CPG reports, depending on mix design and PREVent-C dosage. The product yielded a positive effect for GDOT and had no adverse effect on the concrete production and finishing process, notes Thomas Concrete Director of Technical Ser- vices John Cook. Crews from lead contractor C.W. Mathews Contracting Co. noticed no difference in work- ing with the PREVent-C mixes versus standard bridge concrete, adds Vice President of Structures Adam Grist, who commends state officials for embracing innovative concrete technologies. "Bridge durability [is] severely compromised by shrinkage cracks, which occur due to volume change caused by the drying process as well as other mechanisms," observes Pre- mier CPG Vice President of Sales Jim Preskenis. "PREVent-C is used on any crack-critical structure or when- ever there are shrinkage concerns. In a typical scenario when acceler- ated strength and minimal curing are used, cracking would be visible immediately following the end of curing. On I-85 when the curing was removed, no cracking was observed." — Premier Construction Products Group, Waynesville, N.C., www.pre- miermagnesia.com/cpg Admixture helps Thomas Concrete 'shrink' emergency bridge work schedule Georgia DOT observed PREVent-C mixes' shrinkage and crack control properties on three bridge repair and check template maintenance projects prior to the Interstate 85 over Piedmont Bridges contract, where the admixture was specified for deck and barrier concrete.