Predictive modeling and multi-parameter optimization of geopolymer mixes using SVM-GA hybrid approach
摘要
This study presents a data-driven framework to optimize the mechanical and workability performance of geopolymer concrete (GPC) by refining key mix parameters liquid-to-binder ratio, NaOH molarity, SS/SH ratio, superplasticizer dosage, and curing temperature. Produced from industrial by-products such as fly ash and activated with alkaline solutions, GPC offers a sustainable alternative to cement-based concrete but lacks standardized mix design guidelines due to complex interactions among variables. A comprehensive dataset of 550 samples, comprising 300 literature data points and 250 experimental mixes, was developed to train and validate predictive models. The dataset covers a wide range of parameters: L/B ratio (0.24–0.8), fly ash content (250–530 kg/m3), coarse aggregates (654–1567 kg/m3), fine aggregates (318–817 kg/m3), NaOH molarity (8–16 M), SS/SH ratio (1.5–3.5), and curing temperature (27–100 °C). Experimental results identified optimal mix conditions: L/B ratio of 0.55, 1.5% superplasticizer, NaOH molarity of 10 M, SS/SH ratio of 2.0, and curing at 100 °C, achieving a maximum compressive strength of 43.65 MPa. To address the nonlinear relationships among variables, a hybrid Support Vector Machine optimized with a Genetic Algorithm (SVM + GA) was developed following Mutual Information–based feature selection. The model achieved R2 = 0.9371, MAE = 0.0629, and RMSE = 0.2508 at 80% learning, outperforming Random Forest (R2 = 0.9275) and ANN (R2 = 0.8786). Statistical analysis (p < 0.05) confirmed its significant improvement.