Marwan Sadek

Experimental analysis of the influence of crumb rubber addition on the short-term aging of Syrian asphalt

The use of rubber pavement technology, also known as ecological pavement, offers a solution to a problem of worldwide dimensions. The rubber-modified asphalt becomes an excellent alternative compared to conventional asphalt. A series of laboratory tests was conducted to evaluate the effect of tire rubber addition on the performance of asphalt and asphalt concrete produced in Syria. The paper is composed of three parts: the first part includes a literature review on asphalt aging and the use of modified rubber asphalt in pavement road applications. The second part emphasizes rheological properties of two types of Syrian asphalt hard and soft and analyzes the influence of short-term aging on each type of asphalt. The last part presents a comparison of properties obtained for both cases of nonmodified asphalt and crumb rubber-modified asphalt that have been subjected to short-term aging. Results show an improvement of the resistance to short-term aging for the crumb rubber-modified asphalt. It also demonstrates that adding tire rubber to asphalt improves the performance of asphalt concrete by increasing its stability and reducing permanent deformations.

Elasto-viscoplastic Finite Element Analysis of the Long-term Behavior of Flexible Pavements

ABSTRACT This paper includes analysis of the flexible pavements rutting using an elastoviscoplastic constitutive relation for the asphalt concrete, which takes into account the influence of the temperature. The latter is considered using the time-temperature superposition principle. The loading is modeled as a uniform pressure applied during the vehicle pass. The superposition principle is used for modeling the traffic with a high number of vehicle passes. The numerical model is first calibrated on full scale tests conducted at different values of the temperature. Then, it is used for the analysis of the influence of the temperature and traffic condition on the pavement rutting. Analyses show that the increase in the temperature leads to an import augmentation in pavement rutting. They also show that the tire type and the traffic speed influence significantly the pavement rutting.

Moving element method: A critical review

The paper proposes a preliminary study that aims to investigate the efficiency of the moving element method MEM which is largely used in the literature when solving high-speed moving load problems. Among other, the train/track interaction problem is considered as the main cause of the environmental perturbations that are less and less tolerated by inhabitants. The target is to find a reliable response of the train/track system that can be used to determine the critical position of measuring sensors (optimization study) which are mounted during experimental campaigns.

Modélisation numérique de l'orniérage: Application aux voiries urbaines

ABSTRACT This paper presents a methodology to analyze rutting in flexible pavements using a numerical model that takes into consideration the influence of both the temperature and real loading conditions. Surface layers are modeled using an elasto-visco-perfect-plastic constitutive relation, while the behavior of the base and the subgrade layers are described using an elasto-perfect-plastic model. The model is first calibrated on full—scale tests, then it is used for the analysis of rutting of urban pavements.