The Effect of Aggregate Gradation on Performance of Asphalt Mixture

An adequate and economical design for a pavement structure is just as important as a design for any other engineering structure [1]. It is possible to improve the characteristics of the asphalt mixture, using its components, aggregates and bitumen. Aggregates make up high proportion of volume and mass of asphalt mix; hence, it is predicted to have an enormous impact on the mixture properties. Major characteristics of aggregate are stiffness, shape, texture and gradation, that only gradation can be changed for a special mine. Aggregate gradation is the distribution of particle sizes expressed as a percentage of the total weight [2] and considered as the centerpiece property of aggregate which needs a careful consideration due to its effect on mix properties and performance of HMA mixtures, including air void, stability, stiffness, durability, permeability, workability, fatigue resistance, frictional resistance, resistance to moisture damage [1, 2] and also rutting resistance of asphalt concrete under traffic and environmental loads. So this parameter is considered as a very important parameter in the process of mixture design.