UNCONFINED COMPRESSIVE STRENGTH OF CLAY REINFORCED WITH KEROSENE-TREATED COIR FIBER

Abstract

The need for ground modification is more prevalent as the availability of good site conditions
decrease. Among the available methods of ground modification, soil reinforcement is emerging as a
promising alternative. Fiber reinforcement involves mixing fibers with soil to improve its strength
characteristics. Natural fibers have the following advantages over synthetic: affordability, bulk availability,
and eco-friendliness. Coir fiber has the greatest tensile strength and slowest rate of biodegradation among
natural fibers. This study presents the effect of kerosene-coated coir on strength and stress-strain response of
a cohesive soil. Preliminary soil tests were performed and the soil was classified as CH or high-plasticity clay.
Water absorption capacity tests revealed that kerosene reduces moisture intake of coir by up to 170%.
Reconstituted samples, with fiber concentrations ranging from 0% to 2% by dry weight of soil, were tested
for unconfined compressive strength in optimum moisture and dry states. Results showed that incorporation
of coir improved the strength and stress-strain response of high-plasticity clay by as much as 52% compared
to unreinforced samples. Aside from increasing peak strength, addition of coir also improved the post-peak
behavior of the samples. Results show improved ductility in the coir-reinforced samples tested at optimum
moisture condition. An increase in the elastic modulus, by as much as 78%, was also observed. These
improved performance was exhibited at 1.5% fiber content.