Low temperature cracking (LTC) is a major distress and cause of failure for asphalt pavements located in regions with cold climate; however, most pavement design methods do not directly address LTC. The Thermal Cracking Model (TCModel) utilized by the AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG) relies heavily on the phenomenological Paris law for crack propagation. The TCModel predictions are primarily based on tensile strength of the asphalt mixture and do not account for quasi-brittle behavior of asphalt concrete. Furthermore, TCModel uses a simplified one-dimensional viscoelastic solution for determination of thermally induced stresses. This paper describes a newly developed comprehensive software system for low temperature cracking prediction in asphalt pavements. The software system called “IlliTC” utilizes a user-friendly graphical interface with a stand-alone finite-element based simulation program. The system includes a preanalyzer and data input generator module that develops a two-dimensional finite element pavement model for the user and which identifies critical events for thermal cracking using an efficient viscoelastic pavement stress simulation algorithm. Cooling events that are identified as critical are rigorously simulated using a viscoelastic finite element analysis engine coupled with a fracture-energy based cohesive zone fracture model. This paper presents a comprehensive summary of the components of the IlliTC system. Model verifications, field calibration and preliminary validation results are also presented.
