Mechanical and durability properties of coal cinder concrete: Experimental study and GPR-based analysis

This study investigates the mechanical behavior and durability of High-Performance Concrete (HPC) incorporating coal cinder (CC) as a partial replacement for traditional aggregates, aiming to improve sustainability and performance. While alternative sustainable aggregates have been explored, coal cinder remains a novel choice due to its unique combination of lightweight and pozzolanic properties. The novelty of this research lies in the exploration of coal cinder as an innovative additive for enhancing HPC properties, which has been relatively underexplored. Various CC compositions (ranging from 10 % to 30 %) were analyzed for their effects on compressive strength, splitting tensile strength, flexural tensile strength, density, open porosity, water absorption, and resistance to freezing-thawing and salt attacks. Results showed that as CC content increased, absorptivity and open porosity also rose, while compressive strength improved, peaking at 77.4 MPa with 30 % CC. Despite the increases in porosity, freeze-thaw and salt resistance tests confirmed the durability of the modified HPC. Splitting tensile strength and flexural tensile strength were highest in samples with 30 % and 10 % CC, respectively. Gaussian Process Regression (GPR) was employed to predict these properties, showing high accuracy with RMSE values ranging from 0.29 to 0.38 and Adjusted R² values between 0.85 and 0.92. The strong predictive performance of GPR highlights its applicability for modeling complex materials like HPC. These findings demonstrate that coal cinder additives not only enhance the mechanical properties of HPC but also improve its porosity and durability characteristics, presenting a promising approach for sustainable construction materials.