Strength, durability and microstructural investigations on pervious concrete made with fly ash and silica fume as supplementary cementitious materials

This study attempts to investigate the strength, durability and microstructural properties of Pervious Concrete (PC) made with substitution of Fly Ash (FA) and Silica Fume (SF). A total number of nine pervious concrete mixes were cast to evaluate the aim of this study. Four variable gradation of aggregates (2.36-4.75 mm, 4.75-6.3 mm, 6.3-10 mm, and 10-12 mm) were used in three different proportions. The influence of FA and SF on the properties of properties of pervious concrete such as paste drain down, workability, hardened density, porosity, water permeability, compressive strength, tensile strength, shear strength, ravelling resistance, abrasion resistance, flexural strength, acid resistance was evaluated. Furthermore, the study was extended to observe the microstructural analysis of pervious concrete in terms of Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX). The test results revealed that addition of 10% of FA and SF by weight shows a notable development in strength and durability properties of PC. A significant development of 41%, 85%, and 94% in compressive strength was observed for mix made with 10% substitution of FA and SF at 28, 56, and 120 days. Subsequently, microstructural analysis of PC prepared with FA and SF show densified micrograph with even-layered C-S-H and C-A-S-H gel formation leading higher mechanical and durability characteristics of pervious concrete.