Assessing the engineering properties and environmental impact with explainable machine learning analysis of sustainable concrete utilizing waste banana leaf ash as a partial cement replacement

The production of cement is crucial for sustainable building construction but is costly and contributes significantly to environmental pollution. To address these issues, this research investigates the potential of partially replacing cement with waste banana leaf ash (BLA), a pozzolanic material, in concrete mixtures. The aim of this study is to evaluate the fresh, mechanical, durability, and microstructural properties of BLA-incorporated concrete, alongside its environmental and economic impacts. Experimental methods assessed the workability (slump and compaction factor), mechanical properties (compressive, split-tensile strength, and modulus of elasticity), and durability aspects through Rapid Chloride Penetration Test (RCPT), Water Permeability Test (WPT), sorptivity, and electrical resistivity tests. Results indicate that as BLA content increases, workability declines. Mechanically, BLA concrete generally shows reduced performance; however, the 10% BLA mix improves strength compared to other BLA percentages. Durability tests reveal significant improvements from 28 to 91 days for the 10% BLA mix, with RCPT, WPT, sorptivity, and resistivity increasing by 22.44%, 19.55%, 49.02%, and 18.72%, respectively. Microstructural analysis via Scanning Electron Microscopy (SEM) indicates a decrease in ettringite formation with BLA. Additionally, machine learning models were applied to predict compressive strength, identifying influential factors using SHapley additive explanations (SHAP) and Partial Dependence Plot (PDP) analyses. The 10% BLA concrete mix achieved a 14.78% reduction in Global Warming Potential (GWP) compared to conventional concrete, with a GWP of 426.29 kgCO2-eq/kg, and proved cost-effective. These findings suggest that a 10% cement replacement with BLA presents an optimal balance of environmental sustainability, cost-effectiveness, and strength for construction housing sector.