Index-Based Evaluation and Statistical Modelling of Cassava Peel Ash Blended High-Strength Concrete

Abstract: The rapid growth of the construction sector has increased the need for sustainable materials. High dependence on Ordinary Portland Cement (OPC) contributes significantly to CO₂ emissions. This study evaluates index-based performance and statistical modelling of cassava peel ash (CPA) blended high-strength concrete. Air-dried cassava peels were incinerated at 600°C for 6 hours and sieved to 75 μm. Coarse aggregates were characterized for specific gravity (2.58–2.64), water absorption (0.87%), flakiness (23.75%), elongation (17.5%), and aggregate crushing value (23.75%). Concrete mixes with 0%, 5%, 10%, and 15% CPA were cast and cured in wet sand and water. Compressive and splitting tensile strengths were measured at 3, 7, 14, 28, and 42 days. Performance and durability indices were calculated, and ANOVA and regression analyses were conducted using SPSS. Compressive durability indices ranged from 92.23 ± 10.46 at 3 days to 101.35 ± 9.30 at 17 days, with values of 73.35 ± 49.30 at 21 days and 49.08 ± 56.68 at 28 days. Splitting tensile durability indices ranged from 101.68 ± 33.95 at 3 days to 105.83 ± 8.04 at 21 days and 95.45 ± 7.76 at 28 days. For CPA replacement levels, compressive indices were 99.73 ± 6.06 (0%), 94.71 ± 4.08 (5%), 81.16 ± 31.03 (10%), and 83.18 ± 47.25 (15%), while splitting tensile indices were 76.46 ± 11.32 (0%), 104.70 ± 7.31 (5%), 114.68 ± 18.05 (10%), and 102.30 ± 5.92 (15%). Normality and homogeneity tests confirmed the suitability of data for statistical modelling. CPA incorporation at 5–10% produced optimal durability indices. It is recommended to limit CPA replacement to these levels for sustainable high-strength concrete production.