ABSTRACT
ABSTRACT: The main objectives of this research study were to identify the rut prone asphalt binders (conventional and modified) via the repeated creep and recovery test; and to check whether the measured accumulated strain can be related to the asphalt mixture performance. Creep and recovery testing, which is performed by multiple creep and recovery steps at various stress levels, has been a basic material test for polymers and variety of materials for many years. Federal Highway Administration (FHWA) has recently proposed a new test method called “Repeated Creep and Recovery Test (RCRT)” for asphalt binders to identify the rut susceptible asphalt binders. Furthermore, the National Cooperative Highway Research Program (NCHRP) project 9-19 study has proposed the use of tertiary flow parameter, Flow Number (FN) of cycles, from Repeated Load Permanent Deformation (RLPD) test as one of the Simple Performance Test (SPT) candidates for asphalt mixture testing. In this study several conventional and modified asphalt binders were tested according to the RCRT to identify the rut prone binders. The asphalt concrete mixes were prepared with the same asphalt binders and tested according to the RLPD tests. Since the mix design is the same, the major factor contributing towards rutting of asphalt concrete mixes could be traced to the asphalt binders which were the only component altered between the mixes. The test results suggested that the rut susceptible asphalt binders can be identified by RCRT.
