Effect of Segregation on Fatigue Performance of Asphalt Paving Mixtures

Abstract

The main objective of this research was to investigate the effect of segregation on fatigue performance of asphalt paving mixtures. Segregation in asphalt concrete pavements occurs when coarse material is concentrated in some areas of the pavement and fine materials in others. Segregation has been one problem that has resulted in poor performance in many pavements. Materials used in the study included gravel, natural sand, and an AC-20 asphalt cement. Aggregates were selected to meet the Indiana Department of Transportation specification for a No. 8 binder with a maximum aggregate size of 1 in. (25 mm). To simulate various levels of coarse and fine segregation, four artificially segregated mixtures were prepared in addition to the control asphalt mixture. Slabs were compacted for the five mixtures using the Purdue linear compactor. These slabs were cut into beams that were used to test for the fatigue properties of the five segregated asphalt concrete mixtures. Limits of fatigue were examined when flexural stiffness was one-third and one-half of the initial stiffness at 200 load applications. Results of the investigation indicated that the fatigue life of segregated asphalt concrete mixtures was significantly affected.