عنوان مقاله [English]
Today, several methods are available for improving the physical and mechanical behaviour of the soils unsuitable for construction projects. These methods include compaction, consolidation, preloading, grouting, stabilization by adding chemical materials, etc. Addition of waste crumb rubber to reinforcing the soils is an appropriate method for improvement the strength and bearing capacity of the soils. In addition to the improvement of soil engineering properties, the addition of waste crumb rubber is a measure for the protection of environment. In this study, the shear strength parameters of the kaolinite clay, as the control material, and kaolinite clay reinforced by different percentage of two different types of crumb rubber content have been evaluated. The consolidated drained (CD) and unconsolidated undrained (UU) tri-axial and California Bearing Ratio (C.B.R) tests have been conducted on the control and crumb rubber reinforced soils. Results show that the addition of crumb rubber to the soil results in the improvement of shear strength parameters the ductility f soils. An optimum crumb rubber content is found, which results in the maximum bearing capacity of the soil.The name kaolin is derived from the kao-ling, a village in Jiangxi province, China. Kaolin is composed of white colour china clay. The mineralogical name of Kaolin is Kaolinite, with chemical formula of Al4 (Si4O10)(OH)8 in triclinic system, and the stiffness of 1-2.5 and melting point of 1785 C. Its colour is white tending toward yellow, sometimes- green or blue, tasting soil and intensely smelling soil in wet condition. This mineral is mostly plastic and solouble in water, diluted cold acid, warm and strong choloridric and sulphuric acid and insoluble hydroxide base. Different types of this clay, including ball clay, Halozite, Dikite, and Nakrite can be found in nature. The reasons for the wide applications of this soil in construction materials, ceramics, etc. are being a good filler and coater, softner of surface, resistant against wear, having low conductivity of electricity and heat and katalizator property. On the other hand, due to the industrialization of societies, generation of waste rubber has been greatly increased in recent years. Decomposition of rubber lasts a very long time, and their deposition without appropriate control leads to many environmental problems associated with the rubber are the leaching of harmful materials of buried wastes, and the generation of heat and poisonous gases due their incineration.