Explainable Multi-Target Ensemble Learning with Optimized Hyperparameters for Predicting Mechanical Properties of Eco-Friendly Concrete [Dataset and Code]

1- Dataset Description: This dataset was compiled from 70 peer-reviewed studies published in the literature on Recycled Aggregate Concrete (RAC). The database contains approximately 650 experimental records collected from laboratory investigations evaluating the mechanical properties of RAC. The dataset includes mixture design parameters, recycled aggregate characteristics, aggregate physical properties, and measured mechanical strengths. The database was used to develop and evaluate machine learning models for the simultaneous prediction of compressive strength, flexural strength, and splitting tensile strength of RAC. 2- Variable Description: Variable Description Year Publication year of the source study. Ref Reference identifier corresponding to the original literature source. Compressive strength test Shape Specimen geometry used for compressive strength testing (e.g., cube or cylinder).C1 = 100 x 200 mm cylinders; C2 = 150 x 300 mm cylinders; S1 = 100 mm cubes; S2 = 150 mm cubes. Flexural strength test Shape Specimen geometry used for flexural strength testing (e.g., prism or beam).B1 = 100 x 100 x 500 mm beam specimens; B2 = 150 × 150 x 750 mm beam specimens. Splitting tensile strength test Shape Specimen geometry used for splitting tensile strength testing.C1 = 100 x 200 mm cylinders; C2 = 150 x 300 mm cylinders. Effective Water–Cement Ratio (weff/c) Ratio of effective mixing water to cement content, considering water absorbed by aggregates. Aggregate–Cement Ratio (a/c) Ratio of total aggregate content to cement content in the concrete mixture. RCA Replacement Ratio (%) Percentage of natural aggregate replaced by recycled concrete aggregate. Parent Concrete Strength (MPa) Compressive strength of the original concrete from which the recycled aggregate was obtained. Nominal Maximum RCA Size (mm) Maximum nominal particle size of recycled concrete aggregate. Nominal Maximum NA Size (mm) Maximum nominal particle size of natural aggregate. Bulk Density of RCA (kg/m³) Bulk density of recycled concrete aggregate. Bulk Density of NA (kg/m³) Bulk density of natural aggregate. Water Absorption of RCA (%) Water absorption capacity of recycled concrete aggregate. Water Absorption of NA (%) Water absorption capacity of natural aggregate. Compressive Strength (MPa) Measured compressive strength of RAC; prediction target. Flexural Strength (f′r) (MPa) Measured flexural strength of RAC; prediction target. Splitting Tensile Strength (f′st) (MPa) Measured splitting tensile strength of RAC; prediction target.