Pavement
- Publication no: AP-T240-13
- ISBN: 978-1-921991-97-4
- Published: 10 May 2013
- PDF (free) Download
To assess permanent deformation of granular materials, repeated triaxial tests are currently used in Australia. A previous research project highlighted interest in using a wheel-tracking test to obtain a better agreement with field performance. A new wheel-tracker/compactor was developed and manufactured for unbound granular material characterisation.
Specimen preparation procedures have been developed and assessed, with test repeatability comparable to wheel-tracking tests on asphalt. The density of the compacted slab is uniform except close to the mould sides where wall?effect leads to lower densities. A simple correction to the total mass to be compacted was implemented. The control of the moisture conditions is obtained using a membrane which stops the material drying from the top of the specimen.
A comparison between deformation performance in the laboratory with previous data obtained under accelerated pavement testing exhibited differences. These differences could not be examined in detail in the project timeframe. Results show that further research should be undertaken to investigate fundamental differences in material structure that may occur between wheel-tracking samples and in-service pavement.
- 1. Introduction
- 2. Background
- 2.1. Development of Performance-based Testing Methods
- 2.2. Manufacture and Commissioning of a Wheel-tracking Device
- 2.3. Objectives of the Project
- 3. Equipment
- 3.1. General
- 3.2. Specification for Compaction
- 3.3. Specification for Wheel-tracking
- 3.3.1. Large Device
- 3.3.2. Extra-large Device
- 3.4. The New Wheel-tracker
- 3.1. Mixing Equipment
- 3.2. Slab Mould Assembly
- 3.3. Compaction Device
- 3.4. Wheel-tracking Device
- 3.5. Other Apparatus
- 4. Methodology used for the Development of the Testing Conditions
- 4.1. Introduction
- 4.2. Methodology
- 4.3. Materials used to Develop the Testing Conditions
- 4.4. Testing Program
- 5. Development of the Compaction Procedure
- 5.1. Introduction
- 5.2. Specimen Compaction Process
- 5.2.1. Preparation Sequences
- 5.2.2. Compaction Data
- 5.3. Assessment of the Slab Uniformity
- 5.3.1. Source Material
- 5.3.2. First Specimen (Slab No. 1496)
- 5.3.3. Second Specimen (Slab No. 1630)
- 5.3.4. Findings
- 5.4. Assessment of Unbound Slab Specimens
- 5.5. Correction of the Compacted Mass of Material
- 5.5.1. Simple Correction Method
- 5.5.2. Efficiency of the Correction Method
- 5.6. Conclusion
- 6. Moisture Conditions During Sample Preparation and Testing
- 6.1. Introduction
- 6.2. Moisture Condition after Wheel-tracking Testing
- 6.3. Analysis of the Moisture Variation Mechanism
- 6.3.1. Laboratory Investigation of the Membrane Performance
- 6.3.2. Validation of the Moisture Loss on Wheel-tracker Specimen
- 7. Wheel-tracking Test Results
- 7.1. Introduction
- 7.1.1. Tyre Inflation Pressure
- 7.1.2. Rolling Load
- 7.1.3. Contact Area
- 7.1.4. Average Contact Stress
- 7.2. Permanent Deformation Data
- 7.2.1. Permanent Deformation Data
- 7.2.2. Average Permanent Deformation Calculation
- 7.2.3. Laser Scan Schedule
- 7.3. Laboratory Test Results
- 7.3.1. Inventory of Tests
- 7.3.2. Repeatability
- 7.3.3. Effect of Slab Thickness
- 7.3.4. Influence of Other Testing Parameters
- 7.1. Testing Conditions
- 7.2. Permanent Deformation Testing
- 8. Summary of the Preparation Procedure Developed to Date
- 9. Performance Comparison with Accelerated Loading Results
- 9.1. Data Available from Previous Experiments
- 9.2. Preliminary Assessment of the Materials
- 9.2.1. Particle Size Distribution
- 9.2.2. Compaction Properties
- 9.2.3. Additional Validation Tests
- 9.3. Sample Preparation
- 9.4. Test Results
- 9.1. Contextual Data
- 9.2. Permanent Deformation Results
- 9.3. Graph
- 9.4. Average Rut Depth
- 10. Conclusions and Prospect Suggestions
- 10.1. Conclusions
- 10.2. Suggestions for Future Work
- 10.1. General
- References
- Appendix A Materials Used
- A.1 Particle Size Distribution
- A.2 Modified Compaction Curve
- A.2.1 Crushed Rock Materials
- A.2.2 Material No. 1369 + 5% Cement
- Appendix B Compaction Density Uniformity Assessment Data
- B.1 Slab No. 1496
- B.1.1 Height Measurements
- B.1.2 Directly Measured Density Data
- B.2 Slab no. 1630
- B.2.1 Height Measurements
- B.2.2 Directly Measured Density Data
- Appendix C Method for the Determination of Permanent Deformation Characteristics of Unbound Granular Materials by Wheel-tracking Test
- 1. References
- 2. Definitions
- 3. Equipment
- 4. Test Conditions
- 5. Sample
- 6. Preparation of the Test Specimen
- 7. Permanent Deformation Testing
- 8. Specimen Disassembly and Post-Testing
- 9. Recorded Data and Test Results
- 10. Test Report
- Notes
- Appendix D Wheel-tracking Tests Results
- D.1 Tests Undertaken for Definition of Test Conditions
- D.2 Tests on Previously Tested ALF Materials