Pozzolonic activity and strength activity index of bagasse ash and fly ash blended cement mortar

Abstract Assessment of Pozzolonic activity of certain industrial waste is important due to an increasing need of cementitious material. This study was undertaken to widen the scope of using pozzolanic waste like fly ash and bagasse ash as a supplement to cement. Sugarcane bagasse ash (BA) is a solid waste obtained from the cogeneration combustion boilers in sugar industry and fly ash (FA) is a waste product generated during coal combustion in thermal power plants. The present study is an attempt to determine the pozzolanic activity of BA and FA. Physical properties such as particle size, surface area and specific gravity of ordinary Portland cement (OPC), Sugarcane bagasse ash and fly ash were determined using HORIBA zeta analyzer, BET surface area analyzer and Standard Le-chatelier flask respectively. The chemical composition of OPC, BA and FA was obtained using X-ray florescence (XRF) and the mineralogical analysis was carried out using X-ray diffraction (XRD) technique. Frattini test was conducted to determine hydroxyl ion (OH–) concentration and calcium ion concentration (Ca+2) which is represented through solubility curve. Strength activity index (SAI) was based on the compressive strength test performed on mortar cube specimen which were cast by partial replacement of cement with bagasse ash and fly ash at 10, 20 and 30 percent by weight. The SAI for both BA and FA blended cement mortar was determined after 3, 7, and 28 days of curing and the results compared. The physical and chemical properties of FA and BA meet the requirements as a Pozzolonic material, based on the mineralogical analysis and strength activity index, blending OPC with 20 percent FA or 10 percent BA is beneficial.