Effect of fly ash and metakaolin on pervious concrete properties

Pervious concrete has been studied widely considering its environmental benefits. Owing to its porous nature, it reduces the runoff quantity recharging the groundwater and as well reduces the effect of urban heat island. Previous studies have been focused on characterizing and understanding structural and functional properties of pervious concrete. However, very few studies have been made on incorporating supplementary cementitious materials (SCMs) in pervious concrete. SCMs, which are by-product of production processes from industries, pose several environmental concerns and hence it becomes imperative to utilize them as partial replacement for OPC considering their pozzolanic action, which is beneficial in improving strength and durability properties. In this study, fly ash and metakaolin were used as partial replacement for OPC with curing condition as another variable. Basic tests such as porosity, density, compressive strength, and permeability were conducted to determine the effect of test variables. The curing conditions were found to be insignificant in affecting the properties of pervious concrete unlike fly ash and metakaolin. A 2% addition of metakaolin decreased porosity by 10%, while the optimum range of fly ash replacement in pervious concrete was found to be between 5 and 15%. Statistical tests indicated that fly ash content dominated the effect on influencing permeability and compressive strength. (C) 2019 Elsevier Ltd. All rights reserved.