Effect of Nano Additive on Mechanical Properties of Natural Fiber Reinforced Soil

Abstract

Organic soil is a poor bearing medium and is susceptible to uncharacteristic volume change and settlement behavior. Geotechnical design of substructures in organic soil is often of high economic value to account for its weak geotechnical properties. Fiber reinforcement improves the strength of the soil. However, fibers act as a mechanical reinforcement in soil mass rather than enhancing the intrinsic nature of the soil. But chemical additives alter its behavior, thereby improving its strength. This study investigates the strength and hydraulic conductivity (HC) of low plastic organic silt reinforced with banana fiber and nano-silica. Banana fiber was added in dosages of 0.25%, 0.50%, 0.75% and 1%. The optimum fiber dosage was 0.75%. Nano-silica was added to the 0.75% banana fiber reinforced soil at dosages of 0.2%, 0.4%, 0.6% and 0.8% to improve the strength of the reinforced soil. The effect of aging on HC and unconfined compressive strength (UCS) was studied for a period of 90 d. Results showed that nano-silica and banana fiber beneficially complemented each other in the enhancement of geotechnical properties. Nano-silica increased the strength of fiber-reinforced soil, and banana fiber averted the brittle failure nature imposed by the nano-silica. Also, it improved drainage characteristics through aggregation action.