Experimental Study on Relationships among Composition, Microscopic Void Features, and Performance of Porous Asphalt Concrete

Abstract

AbstractThe performance of porous asphalt concrete (PAC) is dependent on its microscopic void features, which may refer to content and distribution of its constituents. In other words, PAC mixtures with identical air voids may have significantly different performances under given loading and environmental conditions. Air voids and their distributions are determined by aggregate gradation, nominal maximum aggregate size (NMAS), and binder content. Therefore, it is necessary to investigate the correlation among material composition, microscopic void features, and material performance. In this study, X-ray computed tomography (CT) images were obtained and analyzed to study microscopic void features of different PAC mixtures. Experimental tests were performed to study permeability, acoustic absorption coefficients, clogging, shear strengths, wheel tracking, and Cantabro loss of those PAC mixtures. The following findings were observed: (1) microscopic void features were significantly affected by gradation and ...