Evaluation and optimization of mechanical properties of laterized concrete containing fly ash and steel fiber using Taguchi robust design method

The present study employs the S/N ratio and multiple regression analysis to evaluate the mechanical properties of laterized concrete with fly ash and steel fiber. The study considers compressive, split tensile, and flexural strengths as responses at 7 and 28 days. The Taguchi L16 (4 *4) orthogonal array experimental design is applied to optimize the performance of mechanical properties of concrete by using the design of experiments. The replacement of 25% of the granite aggregate with laterite aggregate resulted in a 12.44% increase in the strength of M30-grade concrete after 28 days. The composite's compressive strength decreases when the replacement level exceeds 25%. The split tensile and flexural strengths of the composite showed an increase of 14.54% and 16.93%, respectively, compared to the control mix. Furthermore, the test outcomes for durability factors like drying shrinkage and rapid chloride penetration in steel fiber reinforced fly ash-based lateritic concrete mixes with a 50% replacement rate adhere to the prescribed standards, verifying their designed performance over the designated structural lifespan. However, after multiple regression analysis, it is found that the error related to the correlation between experimental and analytical value strength is about 5%. Microstructural studies of the ideal mix were performed at 28 days to further understand the morphology of the laterized concrete containing fly ash and steel fiber.