A Crack Propagation Model for Asphalt Mixtures Based on the Cyclic Semi-Circular Bending Test

摘要

While the use of Semi-Circular Bending (SCB) test has been successful to characterizethe fracture resistance of HMA, only limited attempts were found in the literature toassess the fatigue resistance of HMA in the laboratory using this geometry. Theobjective of this study is twofold. First, a fatigue crack propagation model wasdeveloped to predict the number of cycles to failure based on a cyclic SCB test and thegeneralized J-integral approach. Second, the effect of creep deformation on the SCB testresults obtained at intermediate temperature was investigated. To achieve theseobjectives, the necessary theoretical formulation is introduced based on fracturemechanics principles. Results of the model were validated based on laboratory testing ofasphalt mixtures using cyclic SCB tests. Results of this study showed good agreementbetween experimental and model predicted SCB test results. Based on these results, it isdetermined that the proposed model provides an acceptable representation of theexperimental fatigue SCB test. Evaluation of the creep deformation in the monotonicSCB test showed that the average energy dissipated due to creep deformation in the SCBtest was 7.1% of the total dissipated energy predicted by the model. This means that 92.9%of the energy is dissipated due to the propagation of the crack in the SCB test. Therefore,the dissipated energy due to fracture is the predominant factor controlling failure in theSCB test.