Image‐based evaluation of deterioration in high‐strength geopolymer concrete using chromaticity and <scp>HSI</scp> analysis

Abstract Deterioration assessment through image analysis enables a quantitative evaluation of surface color changes caused by chemical exposure, and establishes the correlation between the extent of deterioration in high strength geopolymer concrete (HSGPC) and its residual compressive strength. In this study, ambient‐cured HSGPC specimens with compressive strengths of 60, 80, and 100 MPa were exposed to 5% concentrations of HCl, H 2 SO 4 , MgSO 4 , and NaCl for durations of 28, 56, and 90 days. The deterioration was evaluated using chromaticity and hue, saturation, intensity (HSI) image processing techniques, complemented by non‐destructive testing methods. Variations in surface color profiles of the deteriorated specimens were visualized using 3D surface plots. Changes in the CIE‐XYZ color coordinates due to chemical exposure across all durations were analyzed through chromaticity diagrams and compared with the corresponding 3D surface plots. Surface color alterations were further monitored using HSI color space coordinates, in relation to both reagent type and exposure duration. The extent of deterioration, as represented by changes in HSI coordinates, was examined alongside the absorption rate, concentration, and reactivity of each chemical reagent. This novel, image‐based, and non‐subjective evaluation method offers deeper insights into the relationship between deterioration intensity—quantified through color variation—and residual compressive strength. It presents a promising approach for visual spectrum‐based quantification of deterioration in HSGPC.