Effect of gradations on the performance of porous asphalt mixtures

Abstract

This study investigated the effects of aggregate gradation on the performance of porous asphalt mixture. Four different aggregate gradations used invarious countries namely United States, Malaysia, Australia, and Singapore were evaluated and compared in terms of their properties including permeability, durability (abrasion loss), Resilient Modulus, and Dynamic Creep. The optimum bitumen content of each gradation was determined using binder drain down test method. PG-76 bitumen type was used for the design mix of all gradations. Superpave mix design criteria was adopted to prepare the laboratory compacted samples. From the study, it was found that, the designed aggregate gradations havea significant effect on theporous asphalt mixture?s performance. Both resilient modulus and dynamic creep modulus show a significant increase as the coarse aggregate content increases in the gradation. Permeability result shows a direct relationship with the air void contentin the mixture which is a function of theamount of coarse aggregate. Cantabro Loss test result shows a significant increase in the Cantabro loss as the percentage of coarse aggregate increases in the mixture. This indicates that as the porous asphalt becomes more porous the durability of the pavement decreases