Micromechanical Model for Heterogeneous Asphalt Concrete Mixtures Subjected to Fracture Failure

Cracking is a main source of structural distress in asphalt materials and asphaltic pavements. To predict crack-associated fracture damage in asphalt mixtures, this study presents a model using the finite-element method and a cohesive zone fracture model. The approach allows advanced characterization of the microstructural damage evolution in a more realistic length scale, the mixture heterogeneity, the inelastic material behavior, and the interactions among mixture constituents. The model presented herein accounts for (1) actual mixture heterogeneity by using digital image techniques; (2) inelastic material behavior based on elastic-viscoelastic constitutive relations; and (3) microscale fracture damage represented by the cohesive zone fracture model. A computational modeling framework is presented, and the applicability of the model is demonstrated through simulations. Model simulations are further analyzed by comparing numerical predictions to laboratory test results and by conducting parametric analyses of fracture properties. It is expected that the successfully developed computational model can provide better insights into the effect of mixture constituents on overall mixture performance, while minimizing modeling efforts and producing more accurate simulations than traditional approaches, with significant savings in experimental costs and time.