Fracture energy prediction for lightweight aggregate concrete based on ACO method

Lightweight aggregate concrete is a highly durable material that enables cost savings via weight reduction. This material has been continuously improved by researchers and engineers, leading to a high demand for research on lightweight aggregate concrete's basic properties. This study conducts three-point bending tests and analyzes the tensile properties of lightweight aggregate concrete load—crack mouth opening displacement and load.deflection curves. A trilinear tensile softening curve was used to identify the tensile properties of material. The necessary parameters are derived by conducting inverse analysis through the ant colony optimization (ACO) method. The intraclass correlation coefficient of less than 0.01 sufficiently confirmed the reliability of inverse analysis, allowing us to obtain the fracture energy. It was proposed both physical properties of lightweight aggregate concrete and a fracture energy prediction equation that uses the ligament depth and width of the specimen as parameters. In this prediction equation, the experimental results are well predicted with a standard deviation of 0.107 and a coefficient of variation of 0.105 by determining the experimental constants using the existing 85 experimental data of lightweight aggregate concrete.