Development of Guidelines for Usage of High Percent RAP in Warm-Mix Asphalt Pavements

摘要

Road construction using warm-mix asphalt has been rapidly gaining popularity in the United States, in part because WMA is believed to be friendlier to the environment as compared to hot-mix asphalt. Parallel to this rapid growth in WMA construction is utilization of reclaimed asphalt pavement (RAP) in road construction. Research was conducted to develop guidelines for using high percentages of RAP in WMA. The laboratory work was focused on three WMA technologies: water foaming, a chemical additive (Evotherm(TradeName)), and an organic additive (Sasobit(TradeName)). The work included RAP characterization, mix design, moisture damage evaluation, and rutting evaluation using the Superpave Shear Tester and Model Mobile Load Simulator Third Scale. Accelerated load testing was conducted at a temperature range of approximately 42 to 50 degrees C for 400,000 cycles of loading. Rutting resistance of the mixes was rated as fair to good. This research indicates that it is possible to produce WMA with high RAP having sufficient moisture damage and rutting resistance. However, a mix design established for HMA does not necessarily produce satisfactory performance when used with WMA, and it is important that moisture damage and rutting susceptibility of WMA be evaluated for any mix design, even though that mix design may have demonstrated satisfactory performance for HMA.