Determining the properties of semi-flexible pavement using waste tire rubber powder and natural zeolite

Abstract

The small amount of bitumen contained in semi-flexible pavement (SFP) causes the peeling of the aggregate grains, therefore, it is necessary to include some additives such as waste tire rubber (WTR) to increase the adhesion. Moreover, natural zeolite contains a high amount of silica and this makes it suitable as a replacement for cement in SFP filling mortar. This research was, therefore, aimed at determining the compressive strength, flexural strength, drying shrinkage, permeability, durability, and the stress-strain relationship of semi-flexible pavement (SFP) using waste tire rubber (WTR) powder as an additive material and natural zeolite as cement replacement. The porous asphalt mix was designed in accordance with the optimum asphalt proportion and open-graded aggregate as specified in the 2010 Indonesian Bina Marga Standards and 2014 Australian Asphalt Pavement Association (AAPA), respectively. The process involved the addition of WTR powder on liquid asphalt at 3%, 4%, and 5% before the porous asphalt was mixed. This was followed by conducting a Marshall test on the specimens to determine if they satisfied the Bina Marga Standards. The porous asphalt specimens were grouted by cement mortar with the cement content replaced by 0%, 5%, 15%, and 25% natural zeolite (w/w) to produce SFP after which the properties of SFP were tested after 14 days. The results showed the best properties were obtained at 5% tire rubber powder and 15% zeolite content.