In the last years, many researchers studied production of warm asphalt concrete by usingorganic, chemical and water-bearing additive )synthetic zeolite). The purpose of this research is to study theeffect of Syrian natural zeolite on the physical and rheological properties of asphalt binder and verify ofusing it to produce warm asphalt concrete (as a binder modifier or as additive to asphalt concrete), in additionto economic benefits by saving on the cost of synthetic zeolite. In this study, natural zeolite characterizationhas been investigated via X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD) and Thermal Gravimetricanalysis (TGA). Natural zeolite was added to asphalt binder with different percentages (3, 4, 5 and 6%) byweight and to determine the effect of natural zeolite on properties of asphalt binder, penetration at )25(°∁,softening point, ductility, viscosity at (110, 120, 135)°∁ and RTOFT tests were carried out on both modifiedand unmodified aged asphalt binder with natural zeolite. According to the test results, it has been seen thatthe addition of natural zeolite improves properties of the asphalt binder and an increase in its resistance tofatigue, and do not make a substantial difference on the workability of the asphalt binder. So the effect ofthe mixture of natural zeolite additives on the workability could not be predicted on asphalt binder, thereforethe direct effect of additives should be studied on the asphalt mixtures.

For soft soil subjected to earthquake loading, the soil non linearity could significantly amplify the ground motion. This paper presents a 3D numerical study on the influence of soil non linearity on the seismic soil structure interaction for shear wall structures. Numerical simulations are conducted for both elastic and elastoplastic behaviour for the soil. Real ground motions records are used in the study. The analysis is focused on the seismic induced response of the soil and the structure in terms of displacement and velocity. The results show that considering elastic model for the soil behaviour is not sufficient and could significantly affect the seismic induced response of the system.

Algeria, like other Mediterranean countries, is highly exposed to seismic hazards. Several damages have been observed in previous earthquake such as, differential settlements of structures many slope failures and soil movements in Chlef region. This paper presents the results of a series of direct shear laboratory tests on medium fibre reinforced silty sand, highlighting the effect of including fibre content as reinforcement (0.1, 0.25, 0.3 and 0.5% as a fibre volumetric content). The results are analysed and compared with those of unreinforced sand. The tests are carried out for two soil sample states: dry and wet state with a water content of 3%. The experimental results show a clear improvement in the mechanical characteristics with the addition of polyester fibres especially for wet specimens. The fibre addition makes possible to improve not only the shear strength of the soil, but also reduces the volumetric change for a given stress loading, which can contribute to a limitation of the extension-contraction cracks of the soil samples. The percentage of fibres addition is an important parameter which presents an optimum of 0.25% for the undertaken study.

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.

This paper concerns analysis of rutting of urban pavements using finite-element modeling, which takes into account the nonlinear behavior of the pavement materials and the complex traffic condition. A viscoplastic constitutive relation is used for the description of the behavior of the asphalt concrete layer, while an elastoplastic constitutive relation, based on the Mohr-Coulomb criterion, is used for the other layers. The performances of the numerical model are checked over full-scale pavement tests. The model is used for analysis of rutting in urban pavements and for the analysis of rehabilitation methods. Analyses show that urban traffic conditions are detrimental for urban pavements and the use of high resistance asphalt concrete constitutes an efficient alternative for urban pavement rehabilitation.

This paper includes analysis of the flexible pavements rafting 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.

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.

This paper presents a finite element analysis modeling of rutting. The behaviors of the asphalt concrete is described using an elasto-viscoplastic constitutive relation, while an elastoplastic constitutive relation is used for the lower layers. The model allows taking into consideration the influence of both the loading period and the temperature. The numerical model is validated on accelerated pavement tests realized at LAVOC laboratory. Results show that rutting increases with the increase in the contact pressure and in axle load with a dominant role for the axle load. Wheels wander significantly affects the development and profile of rutting. Rutting due to the asphalt layer is generally accompanied by a pavement uplift.

This communication concerns analysis of the behavior of flexible pavements using an elastic-viscoplastic constitutive relation for the asphalt concrete. The numerical model takes into consideration the influence of the temperature on the behavior of the asphalt. The paper presents successively the constitutive relation used in the analysis, the validation of the numerical model on field tests and a sensitivity analysis of the behavior of pavements to a variation of the material properties, the temperature and the period of loading. Numerical results show that the elastic-viscoplastic model reproduces well the behavior of flexible pavements and that the increase in the temperature affects significantly the deformation of the pavement.