Petrographic analysis method for evaluation and achieving durable hot mix asphalt

Abstract

One of the parameters to have a durable asphalt mixture is the existence of high strength materials such as basalt and sandstone. Some experiments indicated that these aggregates should not be used due to their moisture sensitivity and the weakness in the adhesion of bitumen. However, some real world experiences demonstrated that these materials, together with limestone, leads to satisfactory results. Therefore, the aim was to identify the cause of satisfactory results in the used compounds, by examining physical and mechanical properties of the aggregates through microscopic and mineralogical investigations and chemical analyses of the aggregates (petrographic analysis). Asphalt mixture samples are made using different aggregate combinations and are tested using Marshall stability, indirect tensile strength and resilient modulus. The results revealed that petrographic analysis can well describe and predict the behavior of materials. In addition, high stiffness minerals such as quartz, plagioclase, pyroxene, and olivine enhance durability and frictional resistance of the asphalt mixture. Also, the fine aggregates containing sufficient amount of calcite micro-particles prevent the penetration of water by adequately covering hydrophilic aggregates and creating a continuous network of high-adhesive materials. © 2019 Elsevier Ltd