Substitution of Fly Ash as Mineral Filler in Wearing Course of Hot Mix Asphalt

Fly Ash (FA) is one of the sustainable materials to substitute Ordinary Portland Cement (OPC) was found commercialized in construction field but the usage in HMA pavement is limited. Thus, this study is important to promote FA as a sustainable filler instead of using OPC to reduce greenhouse gases. The primary aim is to investigate the Marshall Stability of HMA that incorporating of OPC and FA as filler. In addition, Optimum Bitumen Content (OBC) determination also conducted in this study. Marshall Stability test was conducted based on ASTM 2006 for both mixtures. The parameters gained from the test are the stability, flow, air void in mix (VIM), void filled bitumen (VFB) and stiffness being used to OBC. The OBC for HMA with OPC filler obtained is 5.06% meanwhile for HMA with FA is 4.79%. All Marshall Parameters was complied with of Malaysia Public Work Department (PWD) Standard for both mixtures. The HMA with FA filler give better results for all parameters. Based on OBC percentage, usage of asphalt binder was reduced at 0.29%. Thus, it was more economical if using FA compared with OPC as a filler. Furthermore, HMA with FA filler have better stability and strength as well as lesser deformation with HMA with OPC filler. For the overall, FA have huge potential in substituting other mineral filler to produce better quality of asphalt pavement.