Several National Concrete Pavement Technology (CP Tech) Center programs and staff members are featured in the Accelerated Implementation and Deployment of Pavement Technologies 2016-2017 Annual Report from the U.S. Department of Transportation and the Federal Highway Administration (FHWA). The report touts the work of the AID-PT program in promoting performance-engineered asphalt mixtures, recycled concrete aggregates, thin asphalt overlays, and concrete overlays. And the CP Tech Center has been in the forefront of national efforts to advance these technologies.
Thomas D. Everett, FHWA Associate Administrator for Infrastructure, writes in his introduction to the report, “We want to highlight various technology transfer and outreach efforts, which are central to the program. These activities deliver critical insights, experience, and practices to the pavement community through meaningful and cost-effective strategies. . . And the program is having significant impacts on highway practices.”
Among the shout-outs for the National Concrete Pavement Technology Center (CP Tech Center) in the federal program summary for the past fiscal year:
New specs for concrete paving
Engineering concrete mixtures for better performance requires attention to durability and resilience under increasingly challenging environmental conditions. Peter Taylor, director of the CP Tech Center, is part of a task force that is developing the new guidelines to improve the abilities of the nation’s pavements to withstand whatever traffic and nature throw at them. He comments, “At the heart of the specification is making sure that we are measuring the right things. We found that beyond concrete strength, most of the critical factors that we need for performance are durability related, and typically not captured in existing specifications.” The annual report includes photos from the CP Tech Center showing technicians conducting several tests (such as the Super Air Meter, the box test and the vibrating Kelly Ball test) that are represented in the new provisional guide specificationfor constructing concrete pavements.
Concrete overlays give pavement new life
The benefits of concrete overlays are many, but how do professionals decide when and where to best use these overlays? They can look to the Concrete Overlay Field Application Program, administered by the CP Tech Center, for guidance. “The goal of the program is to provide technical assistance to agencies in the overall concrete overlay process, from the selection of candidate projects through the design and construction of the project itself,” says Dale Harrington, a civil engineer at Snyder and Associates, who oversees the program for the CP Tech Center. Readers of the annual report are directed to visit the center’s website for more information on this technology that has seen significant increases in use since 2009.
Recycling makes sense for roadways
The practice of crushing old concrete for use as aggregate in roadway construction isn’t new, but practitioners are looking at it with fresh eyes. Today, an estimated 140 million tons of concrete are recycled annually from all sources in the US. The process produces a granular material called recycled concrete aggregate (RCA) that offers economic and environmental benefits to roadway builders. While holding down construction costs by eliminating the charges for disposal of the old concrete, RCA also conserves virgin aggregate sources and reduces the energy use and emissions stemming from aggregate production and transport.
Through a cooperative partnership with the CP Tech Center, National Concrete Consortium (NCC) member States, and the concrete industry, the FHWA is leading an effort to promote greater use of technologies to recycle concrete pavement. As part of this initiative, the FHWA and the CP Tech Center formed a technical advisory committee consisting of 10 NCC member States to help demonstrate and expand the use of concrete recycling techniques and technologies.
“We are working to provide highway agencies with information to overcome some of the barriers to the use of recycled concrete aggregate,” says Tom Cackler, project manager at the CP Tech Center. “RCA is a valuable construction product that when properly designed can be used in a range of highway applications.”