Pavement
- Publication no: AP-R650-21
- ISBN: 978-1-922382-65-8
- Published: 30 April 2021
- PDF (free) Download
This report details research undertaken to improve the mechanistic-empirical procedure for pavement rehabilitation and strengthening treatment design included in Austroads Guide to Pavement Technology Part 5: Pavement Evaluation and Treatment Design.
The report describes the research needs and provides a comprehensive roadmap for future work.
The project methodology included a gap analysis, a literature review covering the priority areas, and identification of the most appropriate approaches to be further developed for the Austroads rehabilitation design framework for flexible pavements.
Two primary areas were identified for future improvements of the mechanistic-empirical thickness design approach:
- developing processes to characterise past and future fatigue damage of existing bound pavement materials
- developing a method to design asphalt overlays against reflective cracking.
For the practical application of back-calculation tools, the project also developed a method to evaluate existing back-calculation software.
In the webinar below Dr Didier Bodin and Dr Geoff Jameson provide an overview of the report.
- Summary
- 1. Introduction
- 1.1 Background
- 1.2 Purpose
- 1.3 Scope
- 1.4 Methodology
- 1.5 Report Structure
- 2. Survey of Practitioners: Improvement Needs
- 2.1 General
- 2.2 Stakeholder Engagement Process
- 2.3 Overview of Survey Responses
- 2.4 Summary of Needs
- 3. Evaluation Method for Modulus Back-calculation Software
- 3.1 Introduction
- 3.2 Description of Evaluation Method
- 3.3 Benchmarks for Assessment
- 3.3.1 Introduction
- 3.3.2 The AustBack Algorithm
- 3.3.3 Pavement Configurations and Elastic Characterisation
- 3.3.4 Generation of the Hypothetical Deflection Bowls
- 3.3.5 AustBack Back-calculation Parameters
- 3.3.6 AustBack Deflection Matching Results
- 3.3.7 AustBack Modulus Matching Results
- 3.4 Summary
- 4. Temperature and Moisture Adjustment of Back-calculated Moduli
- 4.1 Introduction
- 4.2 Prediction of Pavement Temperature During Deflection Testing
- 4.3 Modelling Diurnal Temperature in Thick Asphalt Layers
- 4.4 Moisture Prediction Models
- 4.5 Directions for Future Research
- 5. Remaining Fatigue Life of Existing Bound Pavement Materials
- 5.1 Introduction
- 5.2 Scope of Remaining Structural Life Considerations
- 5.3 Overview of Possible Methods to Improve the MEP
- 5.3.1 Using Predicted Design Life at Last Treatment Less Past Traffic
- 5.3.2 Using In Situ Tensile Strains Applied to Existing Bound Materials
- 5.3.3 Reduction in Existing Bound Material Modulus due to Past Traffic
- 5.3.4 Laboratory Fatigue Life of Existing Bound Materials
- 5.4 Summary
- 6. Prediction of Allowable Traffic Loading to Reflective Cracking
- 6.1 Introduction
- 6.2 Overview of Existing Approaches to Reflective Cracking in Pavement Treatment Design
- 6.2.1 General
- 6.2.2 Methods Based on the Paris Law and Fracture Mechanics Principles
- 6.2.3 Methods Based on Continuum Damage Mechanics
- 6.3 Consideration of Approaches for an Improved MEP
- 6.3.1 The CalME Method
- 6.3.2 Method from the Texas Transportation Institute
- 6.4 Summary
- 7. Enhanced Use of Traffic Speed Deflection Data
- 7.1 Introduction
- 7.2 Background
- 7.3 Emerging Modulus Back-calculation Methods
- 7.4 Future Direction for Research
- 8. Strategy for MEP Improvements
- 8.1 General
- 8.2 Research Components
- 8.2.1 Deflection Data Analysis for ME Treatment Design
- 8.2.2 ME Design for Fatigue of Existing Materials
- 8.2.3 Design of Asphalt Overlays for Reflective Cracking
- 8.3 Research Roadmap
- 9. Conclusions
- References