Influence of By-Product as an Alternative Mineral Filler on the Performance of Asphalt Mixtures

Warm mix asphalt (WMA) technology has recently emerged as a promising alternative to minimize energy use and greenhouse gasses emissions along with the progress of the paving industry. It has numerous benefits over hot mix asphalt (HMA) as it can be manufactured at lower temperatures without compromising the performance of pavement. This paper explored the usage of fly ash as an alternative for conventional mineral fillers such as ordinary Portland cement (OPC) in WMA mixture prepared with Sasobit. The study evaluated the service characteristics and mechanical performance of WMA with different types of mineral fillers, as well as mixing and compaction temperatures. The evaluation included analyzing the compaction energy index (CEI), workability index (WI), resilient modulus (MR), indirect tensile strength (ITS) and moisture susceptibility using the tensile strength ratio. Results indicate that FA-filled samples demonstrated better workability and required less energy for compaction compared to OPC-filled samples. The addition of 2% Sasobit and mixing at 145 ℃ significantly improved the workability, reduced compaction energy, and enhanced the structural capacity, with the highest MR values of 5141 MPa for OPC and 5346 MPa for FA. Mixtures with higher mixing temperatures and Sasobit exhibited superior ITS values, indicating better resistance to cracking, with the highest ITS observed in the 2% Sasobit and FA mixture at 145 ℃. FA-filled mixtures also showed higher tensile strength and better moisture resistance, with TSR values of 0.95 compared to 0.94 for OPC-filled mixtures. In general, the addition of fly ash in WMA resulted in higher tensile strength ratio values than the asphalt mixture prepared with OPC regardless of mixing and compaction temperatures. The application of fly ash as an alternative filler would help synergize the sustainability in the construction industry through responsible consumption, hence lowering the depletion of non-renewable resources.