Parametric Sensitivity Analysis of High-Strength Self-compacting Alkali-Activated Slag Concrete for Enhanced Microstructural and Mechanical Performance

This paper presents a parametric sensitivity analysis of High-strength Self-compacting Alkali-Activated Slag Concrete (HSAASC) for enhanced microstructural and mechanical properties by replacing fine aggregates with blast furnace slag. Taguchi's method of Experimental Design was employed to enhance the efficiency of experimental investigation by optimising the total number of experiments conducted. Based on this technique, nine mixes of HSAASC (known as calibration mixes) were designed to conduct detailed experiments. Regression models were formulated to forecast the mechanical characteristics of HSAASC mixes. The correctness of the proposed equations was subsequently validated through a comparative analysis between their projected outcomes and the experimental results obtained from six additional randomly chosen HSAASC mixes (called verification mixes). The findings of this paper reveal that the HSAASC mix labelled as CMIX-7, which contains a binder content of 800 kg/m3, a water-to-binder ratio (w/b) of 0.40, a Na2O percentage of 7.0, and an activation modulus of 1.2, demonstrates greater compressive strength (after 28 days), modulus of elasticity, split tensile strength, and flexural strength, measuring 68.22 MPa, 32,882 MPa, 5.73 MPa, and 8.18 MPa, respectively. Furthermore, it demonstrated enhanced resistance to water absorption and chloride ions penetration compared to the other HSAASC mixes. The mechanical strengths of the HSAASC mix after 28 days are primarily influenced by the percentage of Na2O, followed by binder content, activator modulus, and w/b ratio. Microstructural analysis of HSAASC mixes has highlighted the amorphous morphology and the impact of key parameters on hydration products.