Development of An Environmental-Friendly Durable Concrete

Abstract In this experimental study on Self Compacting Concrete (SCC), the Manufactured sand (M-sand) and Fly ash (FA) were utilised for partial replacement of Natural sand (N-sand) and Ordinary Portland Cement (OPC), respectively. N-sand was partially replaced by M-sand at various percentage levels, after the dose of FA in the mix was optimized. In terms of compressive strength, the optimum replacement level of OPC by FA was 20%, while for replacement of N-sand by M-sand it was 50%. Two types of mixes were made to compare the macro and micro level properties of SCC, i.e., SCC-I (100%OPC+100%N-sand), and SCC-II (80%OPC+20%FA+50%N-sand+50%M-sand). The characteristics of fresh concrete mixes were determined using Slump flow, T50 time, V-funnel, L-box, U-box, and J-ring tests. After 28 days of curing in tap water, both type of specimens were exposed in solution of Ammonium Sulphate [(NH4)2SO4] containing Sulphate salt concentration of 2.0g/l for 360 days to test their durability. Loss in compressive strength, weight change, sorptivity, and micro-structural changes (XRD, SEM, and EDS) all were evaluated up to 360 days. It was found that the use of FA and M-sand in concrete makes it more environment friendly and durable, as well as having higher performance in a sulphate environment.