Effect of Wheel Track Sample Geometry on Results

Abstract

The wheel track test can be used as a means of comparing the permanent deformation behaviour of different types of asphalt mixtures. One advantage of this test method lies in the fact that it can be applied to laboratory compacted specimens and specimens extracted from pavements in the field. However, differences in results have been noted between core samples obtained in the field and laboratory prepared samples with similar mix designs. It is thought that potential reasons for such deviations may be due to differences in the confining pressure of the sample during wheel track loading. One possible reason for such differences may lie in the fact that laboratory prepared samples are composed of rectangular asphalt slab, while field samples are circular and are encased in plaster of Paris to provide testing stability.

This paper describes a study that was performed to investigate the effects of sample geometry on wheel track test.The purpose of this study was to investigate how the specimen geometry affects the outcome of asphalt pavement rutting evaluations conducted through wheel track testing. This research is particularly applicable in Norway where more and more emphasis is placed on designing asphalts to avoid rutting and also to provide correlations between field and laboratory studies.The results of this paper indicate that the encased samples (circular) generally exhibit lower deformation than the square samples.