Effect of Geo Grid Reinforcement on Pavement Sub Grade

A pavement structure consists of a number of layers for the purpose of transmitting and distributing traffic loads to the sub-grade. Rutting is one form of pavement distresses that may influence the performance of road pavements. Soft sub-grade soils are distinguished by their low un-drained shear strength and high compressibility. Thus, such type of sub grade is required to improve by either replacing the existing soil, which is not a practical and feasible option, thus it is required to stabilize the soil and improve its strength. Nowadays reinforcement has been provided to get the desirable strength of sub grade, This dissertation work deals geo-grid reinforcement which are nothing but planar, polymeric (synthetic or natural) materials used in contact with soil/rock and/or any other geotechnical material, for Filtration, drainage, Separation, Reinforcement, Protection, Sealing and Packing. This work describes the useful effects of reinforcing the sub-grade layer with one layer of geo-grid at completely different positions and thereby determination of optimum position of reinforcement layer. The optimum position determined depend on CBR value test was conducted to determine the optimum position of geo-grid. The CBR of a soil increases by 50-100% when it is reinforced with a single layer of geo-grid. The amount of improvement depends upon the type of soil and position of geo-grid. CBR of sub-grade soil is 6.53% without reinforcement and when geo-grid was placed at 0.2H from the top, The CBR value increased to 19.66%. Soaked Condition CBR of sub-grade soil is 4.77% without reinforcement and when geo-grid was placed at 0.2H from the top, The CBR value increased to 4.46%.