Effect of physical and mineralogical properties of aggregates on strength and durability of asphalt concrete

Abstract

Asphalt is a mixture of aggregates, binder and filler. The performance of an asphalt matrix mainly depends on the characteristics of its constituents along with the quality of construction process. As 94-95 percent of the total weight of asphalt matrix consists of aggregates, the performance of the mixture is greatly affected and influenced by the properties of aggregates. In the local asphalt industry, aggregates used to produce asphalt concrete, are tested and approved for the application only by evaluating physical parameters such as LAAV, AIV, and shape tests. In this research, mineralogical properties of aggregates have been systematically analysed along with the respective physical and asphalt properties. Crushed aggregates and lump samples were collected from a number of metal quarries and asphalt plants, representing rock types from three major geological complexes; Wanni, Highland and Vijayan of Sri Lanka. Tests were carried out to evaluate physical and mineralogical properties of aggregate and Marshall stability and flow values of asphalt mixture. The suitability of aggregates for asphalt pavement construction were discussed using the test results. Findings of the research proposes to consider the collective influence of both physical and mineralogical properties of aggregates when selecting competent materials for asphalt concrete manufacture.