Repeatability of reclaimed asphalt pavement as related to properties of bitumen

Abstract

Material recycling is one of the best solution that support sustainability aspect and at the same time reduce the construction and material cost. One of the common method in bituminous recycling is using reclaimed asphalt pavement (RAP). Although usage of RAP in the pavement has been established, properties of bitumen after repeated recycling process is unclear. Bitumen was extracted from recommended recycled mixtures that had undergone through repeated recycling process. In this study, bitumen was assessed in three different ageing stages namely 0 Cycle, 1st Cycle and 2nd Cycle. 0 Cycle is the sample which extracted from fresh mixture (represents 100% fresh materials). 1st and 2nd Cycles represent the number of recycling process. Penetration, softening point and viscosity test were used to evaluate the properties of extracted bitumen. From the tests, the results indicate that repeated recycling process generally increased hardness of the bitumen. This result was proven with the reduction in penetration value and increased in softening point temperature. Furthermore, it was also discovered that multiple recycling stages reduced the mixture workability, which was demonstrated by the increment of viscosity value. Hence, recycling process without any rejuvenator is applicable up to certain levels only.