Sustainable use of normal and ultra-fine fly ash in mortar as partial replacement to ordinary Portland cement in ternary combinations

Abstract

In fiscal year 2020 about 4.1 billion tonnes of ordinary Portland cement (OPC) is produced across the globe. The demand of cement in pace with construction of buildings and infrastructure is expected to increase year by year. Harmful gases such as carbon dioxide is emitted in to the environment in the process of cement production. Researchers and scientists are trying to reduce the consumption of cement significantly by blending cement with any industrial by-products such as Fly Ash (FA), Slag, Metakaolin, ultra-fine slag (UFS), ultra-fine fly ash (UFFA) etc. The present research aims to investigate the effect of OPC, FA and UFFA in 9 ternary combination. OPC is replaced with FA in proportion of 10, 20 and 30% with 10, 15 and 20% of UFFA, there by examining 9 different ternary combinations. The cost, strength and workability properties of 9 ternary mortar mixes are compared with reference mortar (100% OPC). Due to ultra-fine particle size of UFFA, it was observed that, the ternary mix are capable of providing better early strength, which was not possible with only normal fly ash. The study will help to determine the optimum proportions which can satisfy strength requirements and reduce cement consumption with effective utilization of industrial wastes.