Feasibility Study of Performance Grading Particulate Asphalt Rubber Binder

摘要

With the growing use of Crumb Rubber Modifier (CRM) as an asphah modifier there is increased interest in performance-based testing versus current testing. Progress has been made in the past several years using the Standard Specification for Performance Graded Asphalt Binder (ASTM D 6373 and AASHTO M 320) with modifications. The Dynamic Shear Rheometer (DSR) used for high temperature grading specifies a 1 mm gap. When particulate CRM is present, the testing plates' narrow gap causes particle on particle interference in the results. There is an initiative by an AASHTO committee recommending a 2 mm gap for CRM modified binders containing particles 600 microns and smaller. The Pacific Coast Conference on Asphalt Specifications (PCCAS) Round Robin Committee has initiated a feasibility study of full Performance Grading (PG) using one CRM modified binder. This paper addresses the Phase One efforts to test CRM binders with particle sizes of 0.6 to 1.4 millimetres (30 - 14 mesh) using existing specifications and a 3 mm gap for both DSR high and intermediate temperatures. Using ASTM standards for performing inter-laboratory studies has resulted in the data showing strong agreement of variance in inter- and intra-laboratory data and indicates feasibility of the test method.