Thermal Cracking Prediction Model and Software for Asphalt Pavements

Abstract

Thermally induced cracking in asphalt pavements remains to be one of the prominent distress mechanisms in regions with cooler climates. At present, the AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG) is the most widely deployed pavement analysis and design procedure. For thermal cracking predictions, MEPDG utilizes a simplified one-dimensional stress evaluation model with a simple Paris-law (i.e. linear elastic fracture mechanics) based crack propagation procedure. The user-friendly graphical interface for MEPDG makes it an attractive design procedure of choice, however, the over simplicity of the model and lack of a physicsbased representation to accurately capture the nonlinear fracture behavior of ratedependent asphalt concrete reduce(s) the reliability of predictions. This study presents an interactive thermal cracking prediction model that utilizes a nonlinear finite element based thermal cracking analysis engine which can be easily employed using a user-friendly graphical interface. The analysis engine is comprised of (1) the cohesive zone fracture model for accurate simulation of crack initiation and propagation due to thermal loading and (2) the viscoelastic material model for time and temperature dependent bulk material behavior. The graphical user interface (GUI) is designed to be highly interactive and user-friendly in nature, and features screen layouts similar to those used in the AASHTO MEPDG, thus minimizing transition time for the user. This paper describes the individual components of the low temperature cracking prediction software (called LTC Model) including details on the graphical user interface, viscoelastic finite element analysis, cohesive zone fracture model, and integration of various software components for thermal cracking predictions.

Study on Thermal Reflective Cracking of Asphalt Concrete Overlays on Concrete Pavements Under Moderate Temperature Variations Using Finite Element Model

“…The thickness of 4 m was determined based on a sensitivity study with various AB+SG thickness, where no significant change was found in the pavement responses when the AB+SG thickness was above 4 m. The PCC layer consists of three slabs separated by undoweled transverse joints. The joint between the PCC slabs can be modelled with different approaches: empty spaces between PCC slabs ( 12 , 13 ), elements with low stiffness ( 14 ) or cohesive elements ( 15 ). In this study, the cohesive zone modeling (CZM) elements (COH3D8) were inserted to simulate the joint between PCC slabs.…”

IlliTC – low-temperature cracking model for asphalt pavements

“…User inputs and options shown in Figure 2 are discussed in more detail in subsequent sections. For further details on conducting analysis using Visual LTC, the reader is referred to Dave, Leon, and Park (2011).…”

Research on the Fracture Characteristics of Asphalt Mixtures in High Altitude and Cold Regions with Large Temperature Differences

“…Based on the nonlinear finite element method, he proposed an interactive temperature cracking prediction model. This model included a time and temperature-dependent viscoelastic material model, as well as a viscous material fracture model that could accurately simulate the initiation and propagation of temperature loadinduced cracks [8].…”