Pavement
- Publication no: AP-T34-04
- ISBN: 0 85588 710 9
- Published: 21 January 2011
- PDF (free) Download
At the November 1997 meeting of the Austroads Pavement Reference Group (APRG) it was recognised that there was a need to develop procedures which covered all elements of pavement rehabilitation and not simply the structural design of overlays. At that time, the AustroadsPavement Design Guide – which included a chapter on the structural design of asphalt and granular overlays on flexible pavements – was being revised. However, it was agreed that this Guide should cover the design of new pavements only and that pavement rehabilitation, including overlay design, should be the subject of a new, separate publication: Pavement Rehabilitation. A Guide to the Design of Rehabilitation Treatments for Road Pavements.
Austroads commissioned ARRB Transport Research to develop the Austroads Pavement Rehabilitation Guide in consultation with an Austroads Project Advisory Group, which included representatives from Australasian road agencies and industry
This report details the development of these design guidelines for the thickness design of flexible overlays on flexible pavements. Two procedures were developed:
- a chart based procedure which includes a number of simplifying assumptions; and
- a General Mechanistic Procedure (GMP) - a more rigorous approach.
- 1. INTRODUCTION
- 2. ORIGINS OF THE 1992 AUSTROADS OVERLAY DESIGN GUIDELINES
- 2.1. Overview
- 2.2. Design Deflections
- 2.3. Design Curvature
- 2.4. Reduction in Deflections and Curvatures Due to Overlays
- 2.4.1. Reduction in Maximum Deflection due to a Granular Overlay
- 2.4.2. Reduction in Maximum Deflection due to an Asphalt Overlay
- 2.4.2. Reduction in Curvature due to an Asphalt Overlay
- 2.4.3. Adjustment of Asphalt Overlay Thickness to Allow for Locality Temperature
- 2.5. Temperature Correction for Deflections and Curvatures
- 3. OVERVIEW OF THE 2004 AUSTROADS OVERLAY DESIGN METHOD
- 4. DESIGN OF GRANULAR OVERLAYS
- 4.1. Benkelman Beam Design Deflections
- 4.2. Overlay Design Using Falling Weight Deflectometer Deflections
- 4.3. Overlay Design Using Deflectograph Deflections
- 4.4. Reduction in Deflections Due to Granular Overlay
- 5. DESIGN OF ASPHALT OVERLAYS USING DESIGN CHARTS
- 5.1. Introduction
- 5.2. Design Deflections
- 5.2.1. Benkelman Beam
- 5.2.2. Falling Weight Deflectometer
- 5.3. Design Curvatures
- 5.3.1. Introduction
- 5.3.2. Predictions of FWD Curvatures and Standard Axle Asphalt Tensile Strains
- 5.3.3. Asphalt Fatigue Relationship
- 5.3.4. FWD Design Curvatures
- 5.3.5. Overlay Design Using Deflectograph Curvatures
- 5.3.6. Overlay Design Using Benkelman Beam Curvatures
- 5.4. Effect of Asphalt Overlays in Reducing Deflections and Curvatures
- 5.4.1. Introduction
- 5.4.2. Deflection Reductions
- 5.4.2. Curvature Reductions
- 5.5. Design Charts to Evaluate Fatigue of Overlays
- 5.6. Temperature Correction of Deflections and Curvatures
- 5.6.1. Predicted Deflection – Temperature Correction Charts
- 5.6.2. Validation of predicted correction charts
- 5.7. Overlay Procedures for Polymer Modified Binder Asphalts
- Deflectograph
- 6. FLEXIBLE OVERLAYS USING GENERAL MECHANISTIC PROCEDURE
- 7. SUMMARY
- REFERENCES
- APPENDIX A DEVELOPMENT OF DESIGN DEFLECTIONS FOR LIGHTLY TRAFFICKED PAVEMENTS
- APPENDIX B PREDICTION OF DEFLECTOGRAPH CURVATURES RELATIVE TO REFERENCE FRAME
- APPENDIX C FALLING WEIGHT DEFLECTOMETER DESIGN CURVATURE CHARTS
- APPENDIX D EFFECT OF ASPHALT OVERLAYS ON DEFLECTOGRAPH MAXIMUM DEFLECTIONS
- APPENDIX E EFFECT OF ASPHALT OVERLAYS ON FWD CURVATURES
- APPENDIX F VARIATION OF DEFLECTION AND CURVATURES WITH TEMPERATURE
- APPENDIX G FALLING WEIGHT DEFLECTOMETER OVERLAY CHARTS FOR ASPHALT FATIGUE