A Comparative Study on Performance of Malaysian Porous Asphalt Mixes Incorporating Conventional and Modified Binders

The Malaysian Public Works Department (PWD) has recently launched its new specifications and gradations on specialty mixes which includes porous asphalts. Two porous asphalt mix gradations, designated as A and B, were given in the PWD specifications. The aim of this study is to compare the performance of mixes prepared with the two gradations using two bitumen types, namely conventional binder 60/70 and PG-76 modified bitumen. Cylindrical specimens were prepared using the standard Marshall compactor by applying 50 blows on each face. The properties of the mixes were quantified and compared in terms of permeability, air voids, abrasion loss and indirect tensile strength through the water permeability test, determination of air voids, Cantabrian test, and indirect tensile strength test respectively. The results showed the volumetric and mechanical properties of the new Malaysian porous asphalt, as well as provide a better understanding of the effects of aggregate gradations, binder types, and binder contents on mix properties. It was found that Mix B exhibits better hydraulic conductivity and resistance to abrasion loss compared to Mix A, but lower indirect tensile strength. However, the use of modified binder has significantly increased the resistance to abrasion loss and strength of the mixes.