Optimizing concrete mix design is a critical challenge in modern structural engineering, particularly when multiple materials and proportions interact non-linearly. This study presents a systematic optimization of M40 grade concrete incorporating a hybrid fiber combination of Basalt Fiber (BF), Glass Fiber (GF), and Polypropylene Fiber (PF) using the Taguchi L27 orthogonal array. Seven control factors — cement content, water-cement (W/C) ratio, fine aggregate (FA), coarse aggregate (CA), basalt fiber percentage, glass fiber percentage, and polypropylene fiber percentage — were each evaluated at three levels. Nine representative mixes were physically cast and tested for compressive strength (CS) at 28 and 56 days. The remaining 18 mix responses were predicted using the Taguchi additive model. Analysis of Variance (ANOVA) and Signal-to-Noise (S/N) ratio analysis identified the W/C ratio and basalt fiber percentage as the dominant factors, each contributing 78.43% to compressive strength variability and 68.05% to split tensile strength variability. The optimal mix configuration (Mix 19: BF = 0.2%, GF = 1.2%, PF = 1.3%) achieved a CS of 46.9 MPa at 28 days, 53.2 MPa at 56 days respectively. The optimal predicted mix (Mix 22: BF = 0.2%, GF = 1.2%, PF = 1.3%) achieved a CS of 46.49 MPa at 28 days, 52.91 MPa at 56 days. These findings confirm the efficiency of the Taguchi method in reducing experimental trials while predicting the rest of 18 mix designs & identifying the best-performing hybrid fiber concrete mix, Contour Plots

Keywords: Taguchi Method, M40 Concrete, Hybrid Fiber Concrete, Basalt Fiber, Polypropylene Fiber, Glass Fiber, ANOVA, Signal-to-Noise Ratio, Mix Optimization, Orthogonal Array.