| Abstract | Tests conducted following the mix design stage, are unable to assess the rutting potential of asphalt concrete pavements. They range from moving a rubber tire on a slab and monitoring the rut depth to large-scale field tests using accelerated loading facilities. The Strategic Highway Research Program (SHRP) has proposed evaluating induced damage by determining the accumulated permanent shear strains based on a repetitive simple shear (constant height) test. An investigation conducted at the Centre for Surface Transportation Technology of the National Research Council of Canada is aimed at developing a criteria for measuring rutting potential. A repetitive uniaxialcompression test was used to determine accumulated permanent axial strain. Tests were conducted on cores recovered from the field and others compacted in the laboratory using a SHRP gyratory compactor. Test results indicate that the accumulated permanent axial strain undergoes three distinct stages: strain-hardening (volume change), shear flow, and, finally, fracture failure. During the secondary stage (shear flow) the rate of accumulation of permanent axial strain is constant and is sensitive to asphalt mix's resistance to rutting. Performance-related testing of the mix's resistance to potential rutting was carried out at different temperatures. Based on a proposed rutting criterion, one focused on the constant rate of permanent axial strain, the SHRP gyratory compactor simulates field compaction reasonably well. The influence of sample height, applied pressure, and compaction effort on the proposedrutting criterion also was investigated. |
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