Performance Testing of Segregated Hot-Mix Asphalt Samples to Evaluate Segregation Models (05-0437)
Junxia Wu, University of Utah
Pedro Romero, University of Utah

Testing of asphalt concrete samples was done using the Asphalt Pavement Analyzer, the Superpave Shear Tester (SST) Frequency Sweep and the SST Repeater Shear at Constant Height test to determine the level of performance that might be expected from samples that have different levels of segregation. Previous research had divided segregation into four levels: no, light, medium, and high. Test results suggest that samples with different segregation levels might show similar performance, therefore new models were set up in which segregation was divided into three levels: good, fair, and unacceptable. The new models were applied to field data, and examination indicates that the modified models are capable of assessing segregation in field projects. Examination also found that fine segregation was present. Fine segregation can be predicted by extending the developed model from the coarse part to the fine part. However, more data needs to be investigated to set up acceptable criteria for fine segregation. With the models, one can get an idea of “fine segregation” and “coarse segregation”, and the models could be applied to assess realistic construction penalties or incentives by agencies and contractors. Given the promising results from this work, further studies on fine segregation and field implementation on field density measurements are suggested.