Gradation Segregation Characteristic and Its Impact on Performance of Asphalt Mixture

Abstract

The aggregate segregation during construction has a significant impact on the performance of asphalt pavement; however, the segregation evaluation parameters selected by different researchers varied a lot. Also, standard criteria for the impaction of segregation on the performance are still lacking. Therefore, this research proposed a set of segregation evaluation indexes that divided the gradation types into five levels, from coarse-severe to fine-severe gradation. The impact of various segregation levels on the volumetrics, mechanical performance, and road performance of the pavement were evaluated. The mechanical test results indicated that, given the change in the segregation degree from coarse to fine, the Marshall stability and immersive residual stability of the asphalt mixture obviously increased, and the dynamic stability and low temperature failure strain of the heavy segregation gradation obviously decreased. The result also indicated that the rutting resistance first increased first and then decreased because of the cohesion reduction when the gradation was changing from fine to coarse. The result found that the proposed evaluation index can reasonably characterize the degree of aggregate segregation.