On May 25th, FHWA convened part one of a two-part virtual meeting of the Concrete Pavement and Materials Technical Feedback Group. The meeting, led by Gina Ahlstrom (FHWA) and attended by 27 stakeholders in the concrete pavement community, included an update by Professor Norb Delatte (Oklahoma State University) on a research report on early opening to traffic. The draft report, currently undergoing review at the CP Tech Center, suggests among other things that concrete pavement can be opened to traffic at much lower strengths than previously thought without incurring damage to the concrete. The report also includes a discussion about various non-destructive testing (NDT) technologies that can be used to assess strength at early ages, including maturity and stress waves. Tommy Nantung (Indiana DOT) delivered a presentation about new piezo-sensors that can provide real time monitoring of strength for optimal traffic opening time. The technology is still in development, but results are very promising, as output from these sensors correlate extremely well with both stiffness and strength. A wireless version of these small piezo sensors is also in development. Dr. Jason Weiss (Oregon State University) and Dr. Peter Taylor (CP Tech Center) presented on innovative concrete mixture design concepts. As part of subsequent discussions about the role of fly ash in future high durability mixtures, Dr. Tyler Ley (Oklahoma State University) underscored that while conventional sources of fly ash may be dwindling, there is an abundance of high quality reclaimed fly ash in the U.S. – something like 130 years’ worth of fly ash in the ground right now. Leif Wathne, P.E. represents ACPA on this FHWA Technical Feedback Group. Part two of this virtual meeting is scheduled for June 30th, 2021.
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