TL;DR: In this paper, an accelerated pavement testing project carried out at the test facility of the Federal Highway Research Institute of Germany (FHRI) is presented, where two full-scale flexible road pavements were subjected to continued loading while capturing the structural condition.
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. The main objective consisted in analysing and comparing the structural performance of flexible road pavements over their 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 subbase 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 the 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.
TL;DR: In this paper, the simulation of wheel tracking test and the high-temperature rutting behavior of an asphalt mixture by using the discrete element method (DEM) was investigated.
Abstract: This study investigated the simulation of wheel tracking test and the high-temperature rutting behaviour of an asphalt mixture by using the discrete element method (DEM). Based on the DEM software named as Particle Flow Code in three dimensions (PFC3D), a micromechanical model of an asphalt mixture composed of coarse aggregates, asphalt mastic, and air voids was built and a two-dimensional virtual wheel tracking test was simulated. Based on the virtual wheel tracking test, the distribution of displacement and contact forces within test specimen were analysed. It is proved that the built virtual wheel tracking test can capture the rutting deformation caused by the combination of densification and lateral flow deformation. It is also indicated that, within an asphalt mixture, the aggregate skeleton is the main bearing body for the compressive forces, while the compressive and tensile forces between aggregate and mastic are severer than that within asphalt mastic. It is important to guarantee the stability o...
TL;DR: In this paper, the authors defined the resistance to rutting of various kinds of pavement structures and assessed the variation of rut depth in dependence on the traffic loading (number of equivalent standard axel loads).
Abstract: The rutting of asphalt pavement structures during their exploitation is considered to be one of the main problems in Lithuania, as well as in the entire world. This kind of pavement distress makes a negative impact to the exploitation characteristics of the asphalt pavement, to the residual life of pavement structure, also to the safety and quality of the traffic. The main purpose of this analysis is to define the resistance to rutting of various kinds of pavement structures and to assess the variation of rut depth in dependence on the traffic loading (number of equivalent standard axel loads – ESAL‘s). The analysis is performed and is still continued at the road of experimental pavement structures, where 27 different pavement structures were installed. The statistical analysis of the rut depth let to define the most precise criterion for the assessment of every kind of pavement – meridian.