Performance Testing of Segregated Hot-Mix Asphalt Samples to Evaluate Segregation Models

Abstract

Testing of asphalt concrete samples was conducted by using the asphalt pavement analyzer test, the Superpave® shear tester (SST) frequency sweep test, and the SST repeat shear at constant height test to determine the rutting susceptibility that might be expected from samples that have different levels of segregation. Previous research had divided segregation into four levels: none, light, medium, and high. Test results suggest that samples with different segregation levels might show similar rutting susceptibility. Therefore, performance-related models were established in which segregation was divided into three levels: good, fair, and unacceptable. The performance-related 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 extrapolating the developed model from the coarse part to the fine part. However, more data should be investigated to develop acceptable criteria for fine segregation. A methodology was developed to improve pavement quality by controlling aggregate segregation and poor compaction in placed mats. With the models and the proposed methodology, realistic construction uniformity could be assessed by agencies and contractors, which is the first step in obtaining pavements with high performance and longer service life.