experimental study on the effect of crumb rubber on shear strength of sandy soil

nowadays, soil reinforcement using polymer elements have been investigated by a number of researchers in order to increase the load capacity of soils. reinforcing soils using fibers is a method of soil improvement, which offers a homogenous mixture in combination with soils, regarding their tensile strength. this combination maintains pressure loading capacity and properties in mutual resistant tensile. the present research investigates the effect of crumb rubber bearing the size of 5mm × 5mm and 10%, 25% and 40% volume on sandy soil behavior using large-scale direct shear test (300mm × 300mm × 150mm) under the vertical stresses of 50, 100 and 150kpa. results showed that the optimum volume percentage of crumb rubber for maximum shear strength is between 20% and 25%.