Data-driven predictive modeling of steel slag concrete strength for sustainable construction

Conventional concrete causes significant environmental problems, including resource depletion, high CO₂ emissions, and high energy consumption. Steel slag aggregate (SSA), a by-product of the steelmaking industry, offers a sustainable alternative due to its environmental benefits and improved mechanical properties. This study examined the predictive power of four modeling techniques—Gene Expression Programming (GEP), an Artificial Neural Network (ANN), Random Forest Regression (RFR), and Gradient Boosting (GB)—to predict the compressive strength (CS) of SSA concrete. Using 367 datasets from the literature, six input variables (cement, water, granulated furnace slag, superplasticizer, coarse aggregate, fine aggregate, and age) were utilized to predict compressive strength. The models’ performance was evaluated using statistical measures such as the mean absolute error (MAE), root mean squared error (RMSE), mean values, and coefficient of determination (R²). Results indicated that the GB model consistently outperformed RFR, GEP, and the ANN, achieving the highest R² values of 0.99 and 0.96 for the training and testing dataset, respectively, followed by RFR with R² values of 0.97 (training) and 0.93 (testing), GEP with R² values of 0.85 (training) and 0.87 (testing), and ANN with R² values of 0.61 (training) and 0.82 (testing). Additionally, the GB model had the lowest MAE values of 0.79 MPa (training) and 2.61 MPa (testing) and RMSE values of 1.90 MPa (training) and 3.95 MPa (testing). This research aims to advance predictive modeling in sustainable construction through thorough analysis and well-defined conclusions.