Pavement

Cover of Feasibility Study of Using Wheel-tracking Tests and Finite Element Modelling for Pavement Deformation Prediction
Feasibility Study of Using Wheel-tracking Tests and Finite Element Modelling for Pavement Deformation Prediction
  • Publication no: AP-T228-13
  • ISBN: 978-1-921991-79-0
  • Published: 15 March 2013

This report assesses the feasibility of using an advanced analysis of wheel?tracking test data, coupled with a pavement design approach to predict the permanent deformation performance of unbound granular pavements.

The pavement rut resistance method currently used in the Austroads Guide to Pavement Technology Part 2 - Pavement Structural Designglobalises the deformation in the unbound granular layers and in the subgrade, which does not take into account the performance of each base and subbase material. Base materials deformation significantly contributes to total pavement deformation. Improved rut performance characterisation has been identified as a key area of research for unbound base and subbase granular materials.

The first step towards developing an approach was to evaluate the permanent deformation models available from the literature. The second was to build a framework allowing both model calibration and pavement performance prediction. This was completed using a 3D model of the wheel-tracker which was developed to enable the analysis of the wheel-tracking test data in the model calibration stage. The report also presents the model calibration using previous laboratory data. Finally, the model was used to predict pavement permanent deformation.

  • 1. Introduction
    • 1.1. Project Background and Objective
    • 1.2. Current Austroads Permanent Deformation Model
    • 1.3. New Approach Based on Finite Element Modelling
    • 1.4. Scope of this Report
  • 2. Principle of the Proposed Performance-based Approach
  • 3. Literature Review of Material and Pavement Models for Permanent Deformation of Unbound Granular Materials
    • 3.1. Background
      • 3.1.1. Pavement Deformation Mechanism
      • 3.1.2. Permanent Deformation Rate for UGM
      • 3.1.3. Stress Paths in the Roadbed
    • 3.2. Empirical Models Derived from Laboratory Triaxial Tests
      • 3.2.1. Relationship Permanent Deformation versus Number of Loading Cycles
      • 3.2.2. Relationship Permanent Deformation versus Stress Conditions
      • 3.2.3. Methods Based on Resilient Strain
      • 3.2.4. Model Developed for the Constant Deformation Rate Stage
      • 3.2.5. Coupling Effect of Loading Cycles and Stresses
    • 3.3. Pavement Performance Prediction Models
      • 3.3.1. Permanent Deformation Approach Based Design Criterion
      • 3.3.2. Permanent Deformation Calculated from a Layer Approach
      • 3.3.3. FEM Approach Based on Deformation Calculation in a Pavement Cross-section
      • 3.3.4. FEM Approach Based on Deformation Calculation under the Loading Wheel
      • 3.3.5. Main Pavement Models Characteristics
    • 3.4. Performance-based Approach used in Pavement Design
    • 3.5. Candidate Material Performance Relationships
      • 3.5.1. Empirical Relationship for Rutting versus Loading Cycles
      • 3.5.2. Empirical Relationship for Rutting versus Loading Conditions
      • 3.5.3. Four Candidate Relationships used for the First Assessment
  • 4. Available Data
    • 4.1. Wheel-tracking Tests
    • 4.2. Static Triaxial Shear Strength
    • 4.3. Full-scale Pavement Performance Data
      • 4.3.1. Pavement Configuration
      • 4.3.2. Deformation Data
    • 4.4. Data Summary
  • 5. Wheel-tracker Finite Element Model
    • 5.1. Wheel-tracker Model
      • 5.1.1. Validation of Material Model Implementation
      • 5.1.2. Definition of a Loading Cycle
      • 5.1.3. Model used for the Wheel-tracker
    • 5.2. Permanent Deformation Calculation
      • 5.2.1. General Integration Assumptions
  • 6. Calibration of the Permanent Deformation Models
    • 6.1. Material Stress Conditions
    • 6.2. Parameters to be Adjusted
    • 6.3. Model Parameters Calibration
      • 6.3.1. Power Law Relationship
      • 6.3.2. Hyperbolic Relationship
    • 6.4. Analysis of the Model Calibration
      • 6.4.1. Shear Resistance Parameters
      • 6.4.2. Accuracy of Model Fitting
      • 6.4.3. Forms of Calibrated Models
  • 7. Pavement Deformation Prediction
    • 7.1. Pavement Structures and Input Parameters
      • 7.1.1. Unbound Granular Material Parameters
      • 7.1.2. Cement Treated Subbase
      • 7.1.3. Sand and Crushed Rock and Clay
      • 7.1.4. Summary of Material Parameters used
    • 7.2. Wheel Load and Pavement Model
      • 7.2.1. Modelling the Wheel Load
      • 7.2.2. Pavement Finite Element Mesh
      • 7.2.3. Pavement Permanent Deformation Calculation
    • 7.3. Predicted Pavement Permanent Deformation
      • 7.3.1. Predicted Pavement Deformation using Sweere-Lekarp Relationship
      • 7.3.2. Predicted Pavement Deformation using Other Relationships
  • 8. Conclusions and Prospects
    • 8.1. Literature Survey and Approach
    • 8.2. The Finite Element Models and Assessment of the Feasibility
    • 8.3. Suggestions for Further Work
  • References
  • Appendix A Material Model Used for Unbound Granular Materials
  • A.1 Nonlinear Elastic Model
  • A.2 Presumptive Values for Base and Subbase Materials
  • Appendix B Pavement Materials Description
  • Appendix C Pavement Deformation
  • Appendix D Predicted Pavement Deformation
  • D.1 Results Obtained with the Sweere-Gidel Relationship