Case Studies on Successful Utilization of Reclaimed Asphalt Pavement and Recycled Asphalt Shinglesin Asphalt Pavements

Over the past decade, the rapid cost escalation of raw materials used in highway construction has affected the ability of highway and road agencies to maintain their existing pavement system. A common strategy among many highway agencies to offset rising materials costs is to utilize more recycled materials in pavements, particularly Reclaimed Asphalt Pavement (RAP) and Recycled Asphalt Shingles (RAS). Effective utilization of these and other recycled materials in pavements is also consistent with the desire to use more sustainable construction practices in the transportation infrastructure. This report describes the development of specifications and practices of a few state highway agencies that have successfully used RAP and RAS. With regard to RAP usage, the Florida Department of Transportation’s (FDOT's) and the Ohio Department of Transportation’s (Ohio DOT's) programs are highlighted. In Florida, over 75% of all mixes produced for DOT projects contain RAP, with an average RAP content of 22%. The FDOT has found RAP mixes to perform very well. The Ohio DOT also has a long history of recycling asphalt. Like most states, Ohio allows higher RAP contents in lower pavement layers, but allows 5% more RAP when a contractor meets additional processing requirements. Missouri and Texas are leading states in the development of specifications and practices for asphalt mixes containing RAS. Missouri Department of Transportation's (MoDOT’s) effort led to the use of finer grind RAS. Texas and Missouri were among the first states to allow post-consumer RAS in asphalt mixes. Texas has also developed stringent deleterious materials requirements for RAS.