Synergistic Effects of Rice Husk Ash and Ferrochrome Ash on Mechanical Properties, Acid Resistance, Chloride Resistance and Economic Performance of Green Concrete

Cement concrete is reported to be one of the most consumed construction materials, but its production has great environmental implications due to the high consumption of cement. The search for sustainable alternatives to reduce the environmental impact of concrete production has led to the exploration of supplementary cementitious materials. Rice husk ash (RHA) and Ferrochrome ash (FA) are two industrial waste materials that are rich in SiO₂ and Al₂O₃ that remain unutilized causing an environmental burden. The present study presents the effects of blending FA and RHA as SCM on the characteristics of concrete. The research aims to (i) determine the optimum replacement levels, (ii) evaluate the mechanical properties (iii) durability in terms of acid and chloride resistance (iv) internal structural homogeneity through ultrasonic pulse velocity and (v) economic viability through an economy index. A one-way ANOVA test was applied to determine any notable difference between the mean and test data. Out of the various mixes made by using both RHA and FA, the best one was found by applying 3% RHA and 40% FA with 57% OPC. The improvement of compressive, split tensile and flexural strength was observed at 11, 9 and 8% respectively over the traditional mix at the 28-day age. The chloride and acid resistance of FCA (40%) concrete are found 7 and 15% better than traditional concrete. The economic index of RHA and FA blended concrete was found 51% better than traditional concrete. The results showed that both FA and RHA can effectively improve the characteristics of concrete, making them promising alternatives for sustainable concrete production.