An Attempt to Characterize the RAP Material for Hot Recycled Mix Design Purposes

The design of bituminous mixes with high Reclaimed Asphalt Pavement (RAP) content requires the determination of aggregate gradation and the properties of recovered bitumen from RAP. However, in addition to requiring sophisticated equipment, it has been stated by many researchers and practitioners that the current recovery methods have certain other limitations. Hence, the present study focuses on the simple and practical tests from which the properties of the RAP material can be reasonably estimated. The fragmentation test protocol, which was recommended by the RILEM TC264 committee, was evaluated using six sources of RAP of varying properties. Based on test results, it was observed that the fragmentation value determined at 5 °C in combination with the black aggregate curve can be used to predict the percentage fines (<4 mm) in the extracted RAP aggregate (white aggregate curve). It was also observed that the rate of change of fragmentation value with temperature can be correlated to the physical properties of the bitumen extracted from the RAP material.