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2016FallShotcreteEMag

Pool & Recreational Shotcrete Corner Based on the article, “Shotcrete Rising,” originally published in WaterShapes, a pool industry magazine (www.WaterShapes.com). Reprinted with permission. Shotcrete Rising (Part III of a III Part Series) By Lily Samuels and Bill Drakeley The American Shotcrete Association’s 2015 Pool of the Year is simply amazing: Designed by Aquatic Consultants (Miami, FL) and engineered by Watershape Consulting (Solana Beach, CA), the ultra-modern custom pool sits on a difficult site and boasts an all-tile interior among a number of other deluxe features. Truth be told, however, this prize-worthy watershape experienced an unsettling twist on its way to completion: It seems that the original contractor failed to follow established protocols for shotcrete placement, so the resulting shell wasn’t of the caliber specified by the engineer to support the pool’s interior finish. The original shotcrete contractor was summarily dismissed from the project. The substandard shell was ripped out, and a replacement was shot by a new contractor, Revolution Gunite (Burlington, NC), which knew how to follow the protocols the first contractor had ignored. With this huge issue resolved, the project stepped back onto its award-winning path. As we see it, this tale defines two major issues facing the watershaping industry today: first, the need to challenge bad practices and demand excellence; and second, the need to disseminate good information about proper practices to the entire design/build community. In this article, which is the third and last in our series on the developmental history of the shotcrete process, we address this key pair of issues while looking ahead to shotcrete’s future. Out with the Bad As has been discussed in previous articles, the installation of high-quality shotcrete is not a lowbudget endeavor: a qualified, experienced crew must employ the right equipment to place the material, using a good mixture design on a properly prepared substrate. Unfortunately, and all too often, at least one of these three criteria is not respected. Perhaps this is why so many contractors rely on the waterproofing systems that they consider basic insurance policies. With this added material, they believe they are compensating for any possible flaws having to do with poor or inconsistent application techniques, inadequate mixture formulations, or substandard forming. Some even market their reliance on waterproofing as an essential “final step”—that is, as an integral part of the shotcrete process. But nothing could be farther from the truth. In fact, the addition of layers atop the concrete material only increases the risk of bond failure. Through years of experience in critical concrete applications (including the construction of roadway and railway tunnels), we at Drakeley Pool Co. (Bethlehem, CT) know that properly placed shotcrete structures designed to hold water—including swimming pools and spas—are watertight after a 28-day curing period and require no waterproofing before application of the finishing surface. We also know that waterproofing isn’t necessarily an adequate mask for improper shotcrete application. And this is particularly true for projects of the greater level of complexity that are increasingly becoming the norm in high-end watershape design and construction. With swimming pools often being seen as artistic compositions with vanishing edges, perimeter overflows, glass-panel walls, and all-tile finishes, the construction processes involved are much more intricate (and expensive) and therefore raise expectations for flawless execution. To us, flawlessness involves the use of highperforming concrete as a structural foundation that makes it possible to pull all of the specified finishing touches together. In this context, shotcrete failure spells disaster and underscores the need for meeting the concrete industry’s mandated performance criteria. 36 Shotcrete • Fall 2016


2016FallShotcreteEMag
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