High Reclaimed Asphalt Pavement in Hot Mix Asphalt

When old roads have to be replaced, the existing pavement, known as Reclaimed Asphalt Pavement (RAP) is ripped up, milled, and stockpiled and can be used in the creation of new mixes in order to save money and resources. New Jersey state specifications limit the percentage of RAP that can be used to 15% for surface courses and 25% for the intermediate and base courses; however, other states have implemented much higher RAP percentages. The limitations are placed because the interaction between the virgin and residual RAP binder is unknown, with respect to the amount of residual binder that is active in the mix and the effect that this blended binder will have on performance since aged binder has a tendency to be stiffer. In this report, the methods and findings are explained for low temperature laboratory performance of asphalt mixes with 25% and 35% RAP as well as a control mix and RAP samples from Delaware. In addition to this, a coating study, blending study, variability study, and cost analysis were performed and the use of blending charts was investigated. The Superpave Mix Design Excel Spreadsheet was also modified to account for degree of blending. The final section of the report provides recommendations for the use of RAP in New Jersey.