Composite Effect of Fillers on Creep Characteristic of Asphalt Mixture

The influence of mineral filler on the deformation resistance of asphalt mixture was evaluated, in which wearing course (W3B) mixture comprising granite, hydrated lime, and kaolin as filler fraction was investigated. Dynamic creep test on unconfined samples was conducted. Three scenarios of resting periods, namely resting periods for 1 s, 1.5 s, and 5 s, were applied. The test results revealed different enhancement on deformation resistance of the fillers in the mixture. For all scenarios, W3B-hydrated lime showed the greatest resistance to deformation, closely followed by W3B-kaolin, with both being much better than W3B-granite mixture. It was observed that filler’s surface area has a close correlation with deformation resistance of the mixture, thereof filler’s surface area should be controlled to ensure filler can provide optimum effect on asphalt mixture. Herein, each type of filler has its own properties, and will interact differently with asphalt binder, and contributing both to workability and resultant mechanical properties of the mixture. It was demonstrated that resting period provided ‘recovery time’ for the mixture to regain its elasticity.