Microscopic Void Features and Influence of Porous Asphalt Concrete

Abstract:

X ray computed tomography (CT) images were obtained and analyzed to study microscopic void features of various PAC（porous asphalt concrete）mixtures. Experimental tests were performed to research the influence of air voids, aggregate gradation and nominal maximum aggregate size on the microscopic void features and relationship between microscopic and mixture properties. It is shown by the research results that the void equivalent diameter, void area, void quantity and void distribution of PACs mixture were closely related with the mixture’s material composition and performance. For the PAC with approximate air voids, mixture’s microscopic void features had good regression relationship with dynamic stability, Cantabro loss as well as acoustic absorption peak.

Key words:road engineering; porous asphalt concrete; air voids; microstructure; computed tomography technology