Comparative Analysis of Strength Characteristics of Soil Reinforced with Coir and Polypropylene Fibers

Ground improvement through fiber-reinforced soil has been in practice in the recent past. However, with increasing concern for sustainable development, researchers are encouraged to investigate alternative forms of reinforcement than the mainstream synthetic fibers. Coir fibers have been in practice as an alternative natural fiber for ground improvement. In this study, fibers extracted from a local coconut plantation were used to improve the strength characteristics of a local hill soil. The strength characteristics of the soil-coir fiber composite have been compared with the same soil reinforced with synthetic polypropylene fiber. The study investigates the strength variation and change in ductility of both soil-fiber composite with respect to bare soil. The fiber percentage added to soil was selected at 0.5, 0.75 and 1% of the dry weight of soil. A series of unconfined compressive strength (UCS) tests were conducted to ascertain the strength characteristics of the soil. The reinforcement strength results of the soil-coir fiber composite show the efficacy of using such a natural fiber to improve the soil strength characteristics.