Permanent deformation behaviour of a granular material used in low-traffic pavements

Abstract

Granular materials are usually used in low-traffic pavement structure as base layer or sub-base layer. The influence of fine content on permanent axial deformation behaviour is significant as well as the water content. This study aims to investigate the permanent axial deformation behaviour of the granular material under cyclic loading at various water contents and various fine contents. A triaxial apparatus is used to obtain permanent axial deformation on the samples prepared with the same dry density at different water contents between 7% and 11% and at different fine contents of 4%, 7.5% and 15.3%. The results show the significant influence of water content and fine content on permanent axial deformation behaviour. The permanent axial deformation increases with the increase of water content while the influence of fine content depends on the water sensitivity of fine particles and their initial water contents. The modified empirical-analytical models are proposed for describing the evolution of permanent axial deformation based on the results in the single-stage test and the multi-stage tests. It takes into account the number of cycles, the stress level, the water content and the fine content of the granular material. Two approaches are used: one based on the water contents and fine contents and the other based on suction values. The approach based on suction values needs less number of parameters to describe permanent axial deformation compared with the approach based on the water contents and fine contents while the two approaches present more or less the same accuracy. The simulation results show a very good capacity of the proposed approaches. These findings reduce the number of tests required to predict permanent axial deformation.

Hydro-Mechanical Behaviour of an Unbound Granular Base Course Material Used in Low Traffic Pavements

“…In this section, the proposed/modified models for permanent behaviour [4] and resilient behaviour [5] based on the researches for Missillac sand will be verified with the test results (RLTT and SWRC) of UGM Bréfauchet as follows.…”

“…In recent years, the effect of moisture content on deformation behaviour, which was equally important, has been studied by many researchers [4][5][6][7][8][9][10][11][12][13]. These researches showed that the permanent or resilient deformations increased with water content and different prediction models were proposed to evaluate the deformation behaviour of unbound granular materials.…”

“…These researches showed that the permanent or resilient deformations increased with water content and different prediction models were proposed to evaluate the deformation behaviour of unbound granular materials. Especially, based on a long-term research on a subgrade material-Missillac sand (Missillac sand is an alluvium sand coming from the quarry of Missillac in France), authors [4] suggested two approaches (water content and fine content method/suction method) to predict the permanent deformation with different water contents and different fine contents. For the resilient behaviour, an improved Boyce-Hornych model [5] has shown that it has a good adaption to the changing anisotropy caused by the various water contents or fine contents under repeated loading.…”

Study of the mechanical behaviour of reclaimed asphalt aggregates without binder addition

“…Then, the material is taken in tranches in order to obtain homogeneous samples. Based on the researches of Jing et al [21] and Ho et al [22], the sample production needs several steps: -The material is dried in oven at 50°C during 72 hours.…”

Repeated Loading Triaxial Test on Bentonite-Slag-Tire Mixture

“…RLTT (Repeated Tiaxial Loading test) was proved to be very effective way to simulate real loading condition as used by [18,19,20]. Therefore, the RLTT testing has been employed to consider the effect of repeated loading on stabilized soil.…”