Microstructural and Pore Skeleton Characteristics of Pervious Concrete Containing RAP Aggregates Using X-Ray Microcomputed Tomography and Scanning Electron Microscope

Abstract

Pervious concrete is special class of concrete that has application in reducing stormwater runoff and mitigation of urban heat islands (UHIs). This paper studied the morphological and pore structure characterization of pervious concrete (PC) mixes when reclaimed asphalt pavement (RAP) aggregates are used as a replacement of natural coarse aggregates. Scanning electron microscope (SEM) and X-ray microcomputed tomography (XRT) were used to quantify the three-dimensional (3D) changes in the pore structure of PC mix when RAP aggregates are used. SEM investigation conducted on 100% RAP validated that the involvement of RAP aggregates on PC mixes causes asphalt cohesion failure, which will be predominant in reducing the structural and functional properties of PC mixes. The 3D pore structure showed the large number of spheroid-shaped pores when binary-graded PC mix was used. These new findings on the pore morphology will assist in optimizing the use as well as selection of RAP aggregates when used in PC.