Effect of Coal-waste Filler and its Ash on Strength and Durability of Hot-mix Asphalt in Comparison to Limestone Powder

The objective of this research is to investigate the effects of coal-waste powder as a replacement for the conventional filler material on the mechanical properties of hot-mix asphalt. In this laboratory research, using coal-waste filler, specimens with 0%, 25%, 50%, 75% and 100% filler as replacements for the limestone powder were prepared. The performance of hot-mix asphalts containing coal-waste powder was evaluated using Marshall Stability and indirect tensile strength tests. Marshall Stability, liquidity, tensile strength and durability of asphalt mixtures were determined and the effect of mixture of coal-waste and limestone powders on mixture characteristics was investigated. The coal-waste powder was then burned at 750 oC to produce coal powder ash. This ash was then used as filler in hot-mix asphalt and compared with other fillers. The results revealed that coal-waste powder had superior effects compared to limestone powder and, therefore, could be substituted for conventional filler according to performed tests. Moreover, burned coal-waste powder achieved better results than other tested fillers in this research.