Effect of aggregate gradation on the mechanical strengths and permeability properties of porous concrete

Abstract

Porous concrete (PC) is a very popular construction material in developed countries and is now finding application in India in parking lots. In this investigation, an effort was made to study the various performances of PC in the laboratory. Different gradations of coarse aggregates namely 4.75–10 mm, 10–12.5 mm, and 12.5–16 mm are considered to characterize PC adopting conventional compaction by tamping rod, additional 5 and 10 compactions by proctor hammer. The effect of varying compaction and the coarse aggregate gradation is studied on axial compressive, flexural tensile, and splitting tensile strengths of PC. In addition, a simple method is proposed to determine the permeability of all PC mixes. The work was extended to know the influence of low-grade fly ash and GGBS as supplementary cementing materials (SCMs) on the strengths and permeability of PC. Though the strength of PC in the presence of SCMs has decreased, the permeability and the estimated porosity of all mixes decreased compared to the 100% cement counterpart. A wide range of PCs were developed to suit several combinations of mechanical strength, density, and permeability depending on the type of application leading to a sustainable solution. The simple test method proposed to determine the permeability of the PC gives satisfactory results.