01590064

Component

One of the main distresses of a flexible pavement is rutting, a distress in the transverse profile in the wheel path caused essentially by the accumulation of permanent deformation within each layer of the pavement layered system. Rutting is a main load-related distress in flexible pavements and there are two basic types of rutting, asphalt mixture rutting and granular layers, subgrade rutting. The rutting occurring in asphalt layers is strongly related to the properties of asphalt material and the place of the asphalt layer in the structure. In order to investigate the rutting (permanent deformation) of asphalt material, repeated load triaxial (RLT) test is often used to mimic the representative load conditions in the field. The stress conditions and the ratio of loading time to rest period have a significant impact on the test results. In this paper a series of RLT tests are reported with different stress levels, confinement pressures and load patterns. The test results are discussed and a Burgers’ model is employed to explore the elevation of material parameters with regards to the increasing number of load repetitions. The study on the influence of the confining pressure and load patterns on the permanent deformation shows that the stress ratio has a significant influence on the permanent deformation, while the loading pattern has little influence on the development of permanent deformation. This implies that the loading time : rest period ratio as prescribed in the Dutch standard can be used to obtain reliable permanent deformation data although this ratio is rather low. The study of the evolution of the Burgers’ model parameters showed that the viscous parameter ƞ₀ increases with the number of load repetitions. This indicates that the rate of permanent deformation decreases as the number of load repetitions increases. The parameter E₀ hardly changes with increasing number of load repetitions. Parameters E₁ and ƞ₁ decrease with increasing number of load repetitions.

This paper was sponsored by TRB committee AFK50 Standing Committee on Characteristics of Asphalt Paving Mixtures to Meet Structural Requirements.

01584066

16-3995

English

17p

2016

Transportation Research Board 95th Annual Meeting

Digital/other

Figures; References; Tables

Asphalt mixtures; Flexible pavements; Modulus of elasticity; Rutting; Viscosity

Repeated load triaxial tests

Highways; Materials; Pavements; I31: Bituminous Binders and Materials

Transportation Research Board Annual Meeting 2016 Paper #16-3995

TRIS, TRB, ATRI

Jan 12 2016 5:46PM