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This paper presents an integrated computational-experimental approach for evaluating recovered fracture strength after lighthealing of graphite-modified asphalt mixture beams. The cyclic fracture and light-healing tests were conducted to measure the recovered fracture strength of the asphalt mixture samples as reported in another paper. A two-dimensional (2D) multiphase bilinear cohesive zone model (CZM) was employed to predict the original and recovered fracture strength of the asphalt mixture samples. The digital image correlation (DIC) method was used to analyze the crack displacement variation of the samples during the fracture and light-healing processes. The relative strain ratio from DIC, originally measured fracture energy, and peak separation stress were combined to calibrate the recovered fracture energy of beams after light-healing processes. Two input parameters, calibrated fracture energy and peak separation stress, were used to simulate the sample fracture behavior and predict the recovered fracture strength. The relative difference of the fracture strength between the simulation and experiments was calculated to validate the 2D bilinear CZM simulation. The results indicated that the CZM with calibrated fracture energy and measured peak stress is capable of predicting the recovered fracture strength after fracture and light-healing cycles. [ABSTRACT FROM AUTHOR]

The induction healing effects have been experimentally investigated through the cyclic beam fracture and healing testing of asphalt mixture samples with conductive steel wool fibers. This study aims to investigate the healing level of asphalt mixture through the integrated work of laboratory experiment and numerical simulation. Nine single-edge notched beam (SENB) samples containing steel fibers were prepared and used for the laboratory fracture test. Afterward, three divided groups of fractured samples were subjected to the induction healing at controlled temperatures of 60°C, 80°C, and 100°C, respectively. Then the reloading fracture test was conducted with three groups of samples to measure the fracture strength recovery ratio (FSRR) after induction-healing process, which is defined as the ratio of the recovered peak load to the original peak load. The discrete element method (DEM) was utilized to simulate the beam fracture process. A fracture toughness-based bond healing model was used to simulate the microcrack healing effect. The reloading experimental results (after the first healing process) showed that the average FSRR values of sample groups healed at 60°C, 80°C, and 100°C were 0.825, 0.965, and 0.900, respectively. The simulated fracture test results using DEM were in good agreement with the experimental results with respect of the peak load and the slope of load increase. A highly linear correlation between the FSRR and the bond healing level were found based on the numerical simulation and the experimental results. Based on the correlation, the actual bond healing levels of the samples healed at 60°C, 80°C, and 100°C were obtained as 76.2%, 92.1%, and 84.7%, respectively. This study provides a microstructural DEM fracturehealing model to predict the healing level of asphalt mixture by comparing it with experimental data. [ABSTRACT FROM AUTHOR]