Performance Evaluation of Mechanical and Durability Properties of Fly Ash and Silica Fume Based Concrete for Sustainable Building Material

Abstract

he intensive use of cement in construction is a significant environmental concern. To reduce the use of cement for energy consumption, the use of supplementary cementitious materials (SCMs) like Fly ash (FA) and Silica fume (SF) in concrete is an interesting solution. FA and SF-based construction materials offer a lot of potential as alternatives to ordinary portland cement (OPC) because of their high performance and environmental friendliness. The level of replacement and the necessity for additional cementitious content are critical considerations when choosing the most sustainable material for concrete production. To achieve long-term sustainability, the use of FA and SF in the construction industry is essential. Therefore, the authors attempted to identify the preferred material between FA and SF for sustainability by conducting a performance evaluation on the mechanical and durability properties of two binary mixes, i.e., FA and SF-based concrete mixes. The first binary blended concrete mix is prepared by replacing cement with FA at 20%, 30%, and 40% by weight, and the second mix is prepared with SF at 5%,  7.5%, and 10% by weight. The compressive strength (CS), flexural strength (FS), water sorptivity (WS), and rate of chloride penetration (RCP) of these two binary blended concrete mixes were studied. The results show that the incorporation of SF and FA has a significant impact on workability. The use of SF considerably increased the early and long-term strength of concrete, whereas FA lowered early age strength; nevertheless, it enhanced long-term strength. It was concluded that the SF contributed to better durability properties than FA. FA at 30\% and SF at 10\% exhibited the desired strength and durability than OPC, which can be used as a sustainable building material.