Explicit Modeling of Compressive Strength in Manufactured Sand Concrete Based on Integrated Machine Learning Approaches

Abstract

To address the limitations of traditional BP neural networks in predicting manufactured sand concrete strength, specifically their susceptibility to local optima and “black-box” opacity, this study developed an integrated framework combining improved optimization algorithms with the Shapley Additive Explanations (SHAP) method. Using a dataset of 375 data points, genetic algorithm-back propagation (GA-BP) and GOOSE-BP prediction models were developed, with AutoFeat employed for explicit model construction based on a SHAP feature analysis. The results demonstrate that the GOOSE-BP model significantly outperformed traditional methods, achieving an R2 of 0.916 and reducing prediction errors by 47.5%. The SHAP analysis identified paste thickness and stone powder content as the primary determinants of strength. Key thresholds were established, including a water-to-binder ratio sensitivity range of 0.35–0.50, an optimal stone powder content of 80–110 kg/m3, and a recommended sand ratio of 0.38–0.45. By converting complex nonlinear mappings into interpretable explicit expressions, this study provides a robust scientific basis and a practical computational tool for predicting concrete strength, facilitating the deep integration of machine learning with civil engineering practice.