Use of randomly oriented polyethylene terephthalate (PET) fiber in combination with fly ash in subgrade of flexible pavement

This paper is based on the study on the effect of engineering properties of soil by the inclusion of recycled polyethylene terephthalate (PET) fibers in combination with the fly ash in the subgrade soil. The engineering properties, especially studied were the shear strength, shear modulus, California Bearing Ratio (CBR), indirect tensile strength and Atterberg limits using clayey soil. The recycled PET fiber and fly ash were mixed in the clayey soil in various combinations. The proportions ranging from 0% to1.6% by weight of the soil with an increment of 0.4% in respect of PET fibers, whereas from 0% to 20% by weight of the soil with an increment of 5% in case of Fly Ash. The various tests were performed on the samples prepared in varied combinations. The experimental investigations show that there was an improvement in the shear strength, CBR value, and a decrease in the plasticity index. The Optimum quantity found to be, recycled PET fiber 1.2% with 15% Fly Ash by the weight of the soil, which showed improved strength parameters of the subgrade soil.