Performance of Asphalt Mixes Containing RAP

Abstract

Using Reclaimed Asphalt Pavement (RAP) in asphalt mixes has become a common practice in many countries. Experience indicated that the recycling of asphalt pavements is very advantageous from different perspectives. Some of the advantages of utilizing RAP include conservation of asphalt and aggregate resources, conservation of energy and reduction in life-cycle cost. In spite of that, RAP has never been used in Jordan. In this study, the suitability of asphalt mixes using RAP was investigated. Two hot asphalt mixes were prepared following gradations recommended by the Ministry of Public Works and Housing (MPWH/ Jordan). Marshall mix design procedure was used to determine the optimum asphalt content. The first mix was composed of 100% fresh aggregate and virgin asphalt and the second mix was composed of 30% RAP and 70% fresh aggregates and virgin asphalt. Marshal stability, loss of Marshall Stability, water sensitivity, indirect tensile strength, dynamic creep and fatigue tests were performed on samples of the two mixes. Comparing the results of the conducted tests indicated that the use of RAP in Hot Mix Asphalt (HMA) was advantageous in all properties measured except for the fatigue test, where shorter fatigue life was observed. The mix containing RAP showed less reduction in both loss in stability and loss in indirect tensile strength, improved stripping resistance and better creep performance than the mixture with fresh aggregates. Therefore, it is preferred to use mixes containing RAP in highways, where fatigue is not the predominant distress type.