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2016SpringShotcreteEMag

Changing a Culture Takes Time Changing a culture takes time. Missouri’s reputation as a “Show Me” state stands true as MoDOT engineers had to be shown that shotcrete is a viable solution before they opened up their specifications. On June 1, 2011, MoDOT partnered with Concrete Strategies (a St. Louis contractor) and BASF (material supplier) to host a shotcrete demonstration on the substructure of a bridge in Chesterfield, MO. Contractors, consultants, construction inspectors, bridge engineers, and many more observed a live demonstration of shotcrete. This event kindled positive conversations on shotcrete applications, which ultimately had to overcome decades of concerns derived from observations and opinions formed during an era filled with poor quality control, little to no specifications, and no nozzleman requirements. In November of 2011, Dan Millette with Euclid held a shotcrete class for MoDOT in Chesterfield. As a representative of the American Shotcrete Association (ASA), and a former ACI nozzleman By Mark Croarkin examiner, Millette was an excellent source of information to help educate our group on the history of shotcrete, types of equipment, mixture information, safety practices, and much more. ASA has been extremely helpful and more than willing to hold education sessions like this for interested parties. I would strongly recommend that agencies interested in shotcrete take advantage of the expertise within ASA. After a demonstration, some education, and a few field trials here and there, the only thing left was to wait. It takes time to evaluate products, so time is what MoDOT needed to evaluate before allowing shotcrete placement on a more regular basis. Shotcrete repairs are now fairly commonly allowed by Job Specific Provisions (JSP) in Missouri and many construction inspectors have become familiar with its use. While MoDOT relies heavily on ACI 506.2, “Specification for Shotcrete,” each job may have additional considerations. Some portions of the job specifications tend to be enforced more strictly than others. The Fig. 1: June 2011 Chesterfield, MO, demonstration 30 Shotcrete • Spring 2016


2016SpringShotcreteEMag
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