The effects of Gilsonite and Sasobit on the mechanical properties and durability of asphalt mixtures

Abstract To preserve the natural resources and to reduce the environmental pollution related to the construction of pavements, many attempts have been made by pavement engineers to investigate the performance of new technologies and materials. This research aims to evaluate the durability and mechanical performance of asphalt mixtures containing two different types of modifiers including Sasobit as the representative of a modifier for Warm Mix Asphalt (WMA) and a composite modifier made from Sasobit and Gilsonite. The effects of these modifiers were investigated by conducting various tests such as dynamic creep test, indirect tensile strength, resilient modulus, Marshall stability, and fracture tests (using the semi-circular bending samples). The findings of this research indicated that the stiffness of the mixtures was increased and the workability was improved upon the addition of Sasobit. However, Sasobit negatively affected on the moisture susceptibility of the WMA. The use of Gilsonite in addition to Sasobit in the composite modifier further enhanced the thermomechanical properties and durability of the asphalt mixtures. In addition, although the composite modifier is not as effective as Sasobit in reducing the mixing and compaction temperatures, it shows significant improvement in resisting the damages associated with moisture intrusion.