Paving-grade asphalt binders are specified based on their properties in an original state following a specification such as the Performance Graded (PG) Asphalt Binder Specification. However, there has always been an interest in determining the properties of in-place asphalt mixtures for research or forensic investigation purposes. With the increased use of reclaimed asphalt pavement (RAP), many user agencies are also looking for ways to evaluate the properties of the blended asphalt binder (i.e. new binder and old binder from RAP) since this also has an impact on the asphalt pavement performance.
One option is to conduct mixture performance testing. Another option is to conduct solvent extraction-recovery testing on the asphalt mixture and determine the physical properties of the recovered asphalt binder.
This research compares the physical properties of the original asphalt binder, that binder extracted and recovered from a plant-produced asphalt mix and the properties of the asphalt mix with performance testing. The purpose is to evaluate how the various asphalt binder and mix properties rank the quality and performance of the asphalt pavement layer, and compare with (predicted) in-service performance of the asphalt pavements.
Seven asphalt mixes are included in the study using typical PG grades and surface asphalt mixes used in Canada. Two of the asphalt mixes incorporated 15% RAP for comparison with non-RAP mixes. Performance tests conducted on the asphalt mixtures include dynamic modulus, flow number, and flexibility index, which is a performance index used to predict the asphalt mixture’s resistance to cracking obtained from a semi-circular bending (SCB) fracture test.
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