Marshall Parameters of Hot Mix Asphalt with Variable Filler Types and Aggregate Gradations

Abstract

This research aims to evaluate the effect of aggregate nominal maximum size and type of filler on Marshall properties of asphalt mixture. A planned laboratory study is implemented by preparing the asphalt samples using locally available materials and an asphalt binder of 40-50 penetration grade (AC-20). Three types of aggregate nominal maximum size according to SCRB specifications and three types of fillers including limestone dust, cement and hydrated lime were used. Three bitumen contents were used led to nine types of mixtures were prepared and tested that includes all the variables studied. The optimum asphalt content of the asphalt mixture was determined to be 4.75%w using the Marshall method of mix design. A total of 81 Marshall specimens were prepared and tested. The results showed that the aggregate nominal maximum size and filler type have a variable effect on Marshall properties while optimum asphalt content has a significant effect on Marshall Properties regardless of other variables in the mixture. Experimental results showed that using cement as a filler material can significantly increase the Marshall Stability compared to that of using hydrated lime and limestone dust.