Effects of geotextiles on the load-carrying capacity of pavements on sabkha

Abstract

Sabkha soil is widely spread in the Arabian Peninsula, particularly along the Arabian Gulf and Red sea coasts. This soil is associated with some geotechnical problems due to its water sensitivity, low load-carrying capacity and chemical instability. Because of these inferior characteristics, roads constructed on sabkha terrains are subjected to deterioration in the form of raveling, cracking, rutting, formation of potholes and depressions. The main objective of this research is to upgrade the load-carrying capacity of pavements constructed on sabkha soils using geotextiles, and to assess the effect of geotextile grade, base thickness, loading type (static and dynamic) and moisture condition (as-molded and soaked) on the performance of soil fabric aggregate (SFA) systems. In addition, the sabkha soil was treated with different percentages (5, 7, and 10%) of Portland cement and the performance of cement-stabilized sabkha was compared to that of SFA system under different testing conditions. All systems were evaluated by measuring load-carrying capacity at a given value of permanent deformation at the surface of the graded base layer under both as-molded and soaked conditions, taking into account the different testing parameters. The results of this program indicated that the use of geotextile in the construction of roads on sabkha subgrades, will have a beneficial effect on their load-carrying capacities, especially under wet conditions. The sahkha system with geotextile can carry much higher loads compared to the system without the geotextile, especially under soaked conditions. The improvement in the load-carrying capacity of sabkha samples with five percent Portland cement was lower than the ones with A-400 geotextile. However, samples with 7 and 10 percent cement additions showed better results than the inclusion of geotextile.