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Thinlays for Pavement Preservation
Thinlays™, a suite of thin-asphalt overlays designed specifically for pavement preservation, provide road owners with a cost-effective way to preserve pavement life, correct minor distresses, and improve the performance and life of a road. With Thinlays, agencies can extend the life of pavements that are in good to fair condition, decreasing life-cycle costs, improving ride, and decreasing roadway noise.
Thinlays for Pavement Preservation provides comprehensive guidance on the proper use of Thinlays, including how they fit within pavement management systems, when and how they should be used, how to develop and specify Thinlay mixes, and best practices for Thinlay construction. It also helps users compare the cost and performance of common pavement preservation techniques.
Structural Design Guide for Porous Asphalt
Commonly used for parking lots and other light-duty applications, full-depth porous asphalt pavements are increasingly being used on roadways as part of efforts to mitigate flooding hazards, reduce hardscape, and improve sustainability. To help ensure these new porous asphalt roadways provide reliable performance under traffic, NAPA has published Structural Design Guidelines for Porous Asphalt Pavements.
Written by Charles W. Schwartz, Ph.D., and Kevin D. Hall, Ph.D., P.E., with the support of the NAPA–SAPA Pavement Economics Committee's Pavement Design Task Group, Structural Design Guidelines for Porous Asphalt Pavements discusses the structural design procedure for porous asphalt and the required inputs using the AASHTO 93 design method.
The Most Commonly Recycled Material? Asphalt
The latest NAPA/FHWA survey of asphalt producers' use of recycled materials and warm-mix asphalt finds that more than 78 million tons of recycled materials — mostly reclaimed asphalt pavement and recycled asphalt roofing shingles — were put to use in new asphalt pavements during 2017. The same survey found that nearly 39 percent of all asphalt pavement mixture produced during the 2017 construction season was produced using energy-saving warm-mix asphalt technologies.
The survey, conducted by NAPA in partnership with FHWA for each construction season since 2009, found that more than 147 million tons of WMA was produced in 2017. In 16 states, more than half of all asphalt pavement mixture was produced as WMA; in eight of those states, more than 75 percent of asphalt pavement mixture was produced using WMA technologies.
The survey also found that more than 76.2 million tons of reclaimed asphalt pavement (RAP) and nearly 950,000 tons of recycled asphalt roofing shingles (RAS) were used in new asphalt pavement mixes in the United States during in 2017. Reclaiming and reusing the asphalt cement in RAP and RAS saved more than $2.2 billion in 2016 compared to the use of virgin materials and saved nearly 50 million cubic yards of landfill space from reclaiming RAP alone.
A full copy of the survey, including appendixes with state-by-state data, can be downloaded from www.AsphaltPavement.org/recycling.