Investigation of Thin Pavements Rutting Based on Accelerated Pavement Testing and Repeated Loading Triaxial Tests

Abstract

This paper discusses the permanent deformation behavior of unbound aggregates used in accelerated pavement test (APT) sections. A traffic simulator loaded two test pavements consisting of surface treatment, dense crushed rock bases, and macadam subbases. The dependence of rutting evolution on stress state was verified, and a model relating rut depth to load repetition was derived. A laboratory study was carried out to verify if pavement rutting could be estimated by permanent-strain laboratory testing. The first stage of the investigation focused on the strain behavior of the dense graded crushed rock used in bases. Specimens were tested in a triaxial chamber in which repeated loadings were applied. Laboratory results and APT showed similar trends even if some of the results were unexpected. Rut depths in the APT test sections were noticeably more than expected from the permanent deformation in specimens in the triaxial apparatus. Although it seems clear that the investigation must be extended to the macadam aggregate and to the subgrade soil, the approach presented seems suitable to predict rutting of thin asphalt pavements.