Influence of Filler Type on Hot Mix Asphalt Properties: Performance Assessment of Bajil Limestone and Sana’a Basalt

Abstract

Mineral filler selection significantly influences the mechanical performance and economic efficiency of Hot Mix Asphalt (HMA). This study evaluates two locally available Yemeni fillers, Bajil limestone and Sana’a basalt, to identify a technically and economically optimal alternative for pavement construction. Marshall mix design and standardized laboratory tests were conducted to assess stability, flow, volumetric properties, optimum asphalt content (OAC), and moisture susceptibility. Results indicate that the limestone mixture achieved an OAC of (3.8%), compared to (4.8%) for the basalt mixture, representing a 21% reduction in asphalt binder demand and substantial cost savings. Although basalt provided slightly higher Marshall stability, both mixtures satisfied specification requirements. The limestone mix demonstrated superior moisture resistance, achieving a tensile strength ratio of (90.7%) compared to (82.6%) for basalt. Overall, Bajil limestone provides adequate mechanical performance, improved durability, and enhanced economic efficiency, making it a practical and sustainable alternative filler for asphalt pavement applications in Yemen.