Effect of Fine Aggregate Angularity on Asphalt Mixture Performance

摘要

Superpave aggregate qualification includes the fine aggregate angularity (FAA). Fine aggregate angularity levels used in the Superpave system are below 40, 40 to 45 and above 45. The higher values are specified for layers near the surface and for higher traffic levels. The objective of this study was to address the effect of fine aggregate angularity on asphalt mixture rutting performance. A total of 18 mixtures were designed according to the Superpave volumetric design criteria. A surface mixture utilizing a partially crushed 9.5mm coarse aggregate and a single PG 64-22 binder were utilized. The poor quality coarse aggregate was used to maximum the effects of the various fine aggregates. Tests conducted included PURWheel Laboratory Wheel Tracking Device, Simple Shear Test (SST), Compacted Aggregate Resistance (CAR) test, and Florida Bearing Value. Test results indicated that the use of fine aggregate angularity (FAA) does not be itself assure good mixture rutting performance. Other factors such as mixture gradation, asphalt content, dust amount and mixture compactibility also influence mixture rutting performance. A performance test such as the PURWheel laboratory wheel tracking device can be used to assure that mixtures will exhibit the desired level of rutting performance.