Relationships Between Structural, Functional, and X-Ray Microcomputed Tomography Parameters of Pervious Concrete for Pavement Applications

Abstract

Several countries have begun using pervious concrete (PC) pavements to reduce the adverse effects of impermeable surfaces resulting from high-impact development. Pore parameters and their relationship to other PC properties are not yet fully understood; however, this information is essential for rational designs of PC pavements. This study investigated the strength, functional, and permeability properties of 18 PC mixtures and used X-ray computed microtomography methods to determine the three-dimensional pore parameters and their relationships, which were thought to affect PC properties. The major findings of this study included the observation that the failure mode in compression was of the shear brittle type, in which the failure plane was inclined at 45° to the ground, and impact abrasion resistance was higher for larger-sized aggregates and was chiefly attributable to the individual aggregate particles debonding. Permeability was more sensitive at low hydrostatic pressure than at higher pressures. The sphericity and compactness of pores had positive correlations with each other, unlike the relationship between surface area and sphericity. The tortuosity calculated for six of the PC mixtures was less than one; this finding was attributed mainly to the single-sized pore structure. Tortuosity increased with an increase in porosity and permeability and decreased with increasing surface area and pore radius. This research should move the current understanding of PC pore structure one step forward and, therefore, will be helpful in modeling PC in a rational manner.