Comparative study of fly ash and rice husk ash as cement replacement in pervious concrete: mechanical characteristics and sustainability analysis

Abstract

Pervious concrete is a special type of concrete consisting of cement, coarse aggregate and water. Cementis a widely used raw material for construction including pervious concrete and had led to the release ofhuge amounts of CO2to the environment. Therefore, there is lot of research interest infindingsupplementary cementitious materials. The present study examined and compared the feasibility ofusing industrial wastefly ash (FA) and agricultural waste rice husk ash (RHA) for sustainable perviousconcrete production. An experimental program was performed with substitution of FA and RHAcontents of 5%, 10%, 15% and 20% as cement replacement and water to binder ratio of 0.3, 0.35, 0.4and 0.45. The characteristics of pervious concrete and sustainability analysis were compared for bothFA and RHA replacement with control concrete mortar. The results showed that both FA and RHAhave a negative effect on permeability. The compressive strength was optimum for FA content liesbetween 10% and 15% replacement level and RHA content of 5% replacement level. Furthermore, theutilisation of FA and RHA decreased production cost, the total embodied energy and carbon emission,resulting in cost-effective and eco-friendly pervious concrete