Performance Evaluation of Mechanical Properties of Polymer-Modified Binders and Friction Course

Abstract

The two types of friction course materials, including conventional porous asphalt and conventional polymer (SBR) modified porous asphalt, are commonly used on roads in Hong Kong. The dry mixing method was applied to produce the conventional polymer (SBR) modified porous asphalt as the materials produced in the local batching plant. Nowadays, the pre-blended polymer (SBS) modified porous asphalt is gradually introduced and used due to its superior durability performance. This paper presents the details of a laboratory programme to evaluate the three types of porous asphalts. The materials tested involves the three types of binders, including conventional penetration 60/70 binder, conventional polymer (SBR) modified binder and pre-blended polymer (SBS) modified binder, and their respective porous asphalts. The binder test results indicate that two polymer (SBR and SBS) modified binders have the smaller temperature susceptibility and exhibit the better performance in resisting ageing, rutting and fatigue than the conventional penetration 60/70 binder. They are more suitable to be used than the conventional 60/70 in the hot climate areas. The mechanical properties and durability performance of the three types of porous asphalts are judged by the value of stiffness modulus and the ability of resisting water damage, permanent deformation and rutting. Tests are conducted using Nottingham Asphalt Tester (NU-10), Nottingham Wheel Tracker and Humboldt Indirect Tensile Strength Tester. All testing specimens were fabricated by Superpave Gyratory Compactor (SGC). The testing results show that the polymer (SBS) modified porous asphalt exhibit the most satisfactory performance overall with respect to stiffness, axial permanent deformation, rutting, and good resistance to moisture damage among the three types of porous asphalts and will be