Prediction of Asphalt Concrete Low-temperature Cracking Resistance on the Basis of Different Constitutive Models

The top-down cracking of asphalt concrete pavements caused by thermal factors are very common in Poland. Cracking can occur as a result of a single intensive event (severe temperature drop) or as a result of cyclic long-term less severe events (thermal fatigue). In both cases precise constitutive modeling of materials is a key issue for rational prediction of the pavement behavior. As a starting point the Thermal Stress Restrained Specimen Test (TSRST) in which the shrinkage proceeds due to temperature reduction is analyzed and compared with experiment results for chosen mix. The TSRST is modeled using the finite element method in a frame of thermo-mechanics with the so-called weak coupling between thermal and mechanical effects. Mechanical properties are taken into account by the constitutive relations of elasticity, visco-elasticity and continuum cracking models. Among the continuum cracking models special place is devoted to cohesive zone model which is a new development in fracture mechanics. Cohesive zone model in many works is presented as the only solution for rational modeling of TSRST and this notion is also addressed herein.