Analysis of the Long-Term Structural Performance of Flexible Pavements Using Full-Scale Accelerated Pavement Tests

Abstract

This paper presents the results from an accelerated pavement testing project carried out at the test facility of the Federal Highway Research Institute of Germany [1]. The main objective consisted in analysing and comparing the structural performance of flexible road pavements over service life. For this purpose two full-scale flexible road pavements were subjected to continued loading while capturing the structural condition. The test sections were uniformly constructed with an asphalt base course on a gravel base laid on a sub-base but differed in the thickness of the asphalt layers and the use of an asphalt binder course. During testing the surface deflection was measured and the transverse evenness was monitored. Strain gauges were used to detect changes in the structural behaviour under loading. Samples were taken from one pavement after loading to analyse structural cracking. The measurement results show a significant decrease of the structural strength of both pavements, accompanied by bottom-up cracking in the asphalt road base in one test section. In case of the test section with the thinner asphalt pavement the development of the bearing capacity and cracking in the asphalt base indicate a structural failure. The loading of the stronger pavement had to be interrupted early due to technical reasons. The comparison of the data from both sections shows significant differences in view of the total decrease of structural strength as well as the rate of deterioration.