Vane shear strength of bio-improved sand reinforced with natural fibre

Abstract

In the recent developments, bio-improvement has considerably enhanced the geotechnical properties and reduced degradation of loose desert sand without the environmental concerns. However, the effect of bio-improvement on sand weakens due to water submergence. Therefore, it is necessary to explore the techniques for retaining the strength of bio-improved sand in water submerged state. So, this paper reports the geotechnical performance of submerged bio-improved sand reinforced by discrete natural fibres. The desert sand sampled from Al-Sharqia Desert of Oman, bio-improved by xanthan gum and reinforced by discrete natural fibres obtained from date palm tree. Date palm fibres having a diameter less than 0.2mm and length 1cm were employed for sand reinforcement. Vane shear tests and standard compaction tests were performed on specimens having different mix ratios of sand-xanthan gum with and without natural fibres. The qualitative description of bio-improvement and fibre reinforcement effect on the desert sand is also presented as the photomicrographs taken by field emission scanning electron microscope. According to the results of strength tests at higher moisture content state, the discrete fibre reinforcement has enhanced the geotechnical performance of sand improved at lower concentrations.