Energy absorption, secant modulus and compressive strength of fiber reinforced high fly ash content cement treated soil

Abstract

This paper presents the results of an experimental investigation that was conducted to study the behavior of fiber-reinforced, high fly ash content and cement treated soil specimens under unconfined compression tests. The effect of fiber inclusions, curing time and fly ash-cement (FA/C) ratio on unconfined compressive strength (UCS), energy absorption (EA), secant modulus of elasticity (ES) and brittleness index (IB) have been studied. Fly ash of 50% and 70%, and cement content of 1.5% and 2% by weight of soil were used in this study. The fly ash and cement as a cementing agent played a significant role in increasing the compressive strength. The unreinforced mix specimens showed a significant improvement in UCS. The fiber inclusions further increased the compressive strength and improved the ductility of the mix specimens. The increase in fiber inclusion was observed to have an increasing effect on UCS, energy absorption, and secant modulus. The increase in curing period (0, 7, 14 and 28 days) also had similar effect on UCS, EA, and ES. However, the increase in fiber content decreased the brittleness index whereas the increase in FA/C ratio increased the brittleness index of the mix specimens. The study suggests a viable method for improving UCS and reduce brittleness of the soil media which may be beneficial for subgrade stabilization.