Top-Down Cracking of Hot-Mix Asphalt Layers: Models for Initiation and Propagation (2010)

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ACKNOWLEDGMENT This work was sponsored by the American Association of State Highway and Transportation Officials (AASHTO), in cooperation with the Federal Highway Administration, and was conducted in the National Cooperative Highway Research Program (NCHRP), which is administered by the Transportation Research Board (TRB) of the National Academies. COPYRIGHT INFORMATION Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein. Cooperative Research Programs (CRP) grants permission to reproduce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, FAA, FHWA, FMCSA, FTA, Transit Development Corporation, or AOC endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP. DISCLAIMER The opinions and conclusions expressed or implied in this report are those of the researchers who performed the research. They are not necessarily those of the Transportation Research Board, the National Research Council, or the program sponsors. The information contained in this document was taken directly from the submission of the author(s). This material has not been edited by TRB.

i CONTENTS Acknowledgments.......................................................................................................................... iii  Executive Summary .........................................................................................................................1  1. Background ..................................................................................................................................5  1.1 Problem Statement ..............................................................................................................5  1.2 Research Objective .............................................................................................................5  1.3 Research Scope ...................................................................................................................6  2. Research Approach ......................................................................................................................9  3. Findings: The VECD-Based Model ...........................................................................................12  3.1 Framework ........................................................................................................................12  3.1.1 Inputs Module .........................................................................................................13  3.1.2 Material Property Sub-models ................................................................................15  3.1.3 Analytical Sub-models ...........................................................................................48  3.1.4 Performance Prediction Module .............................................................................59  3.1.5 Output Module ........................................................................................................69  3.1.6 Model Integration ...................................................................................................72  3.2 Example Simulation ..........................................................................................................75  3.2.1 Introduction ............................................................................................................75  3.2.2 Simulation Results and Discussion ........................................................................76  3.3 Model Evaluation: Parametric Study ................................................................................77  3.3.1 Introduction ............................................................................................................77  3.3.2 Effect of Region .....................................................................................................80  3.3.3 Effect of Structure ..................................................................................................81  3.3.4 Effect of Unbound Layer Property .........................................................................81  3.3.5 Effect of Asphalt Mixture Properties .....................................................................82  3.4 Summary of Findings .......................................................................................................83  4. Findings: The HMA-FM-Based System ....................................................................................85  4.1 Framework ........................................................................................................................85  4.1.1 Inputs Module and Indirect Tensile Test ................................................................86  4.1.2 Material Property Model ........................................................................................89  4.1.3 Pavement Response Model .....................................................................................92  4.1.4 Pavement Fracture Model .......................................................................................93  4.1.5 Outputs ...................................................................................................................96  4.1.6 Model Integration ...................................................................................................96  4.2 Model Evaluation: Parametric Study ................................................................................99  4.2.1 Effects of Material and Structural Properties .......................................................102  4.2.2 Effect of Traffic ....................................................................................................110  4.2.3 Effect of Climate ..................................................................................................111  4.3 Model Calibration and Validation ..................................................................................113