Stabilization of Low Plastic and High Plastic Soil using Biopolymer

Abstract

Throughout the evolution of human civilization, soil stabilization has been an important consideration. In geotechnical engineering soil stabilization provides viable and cost-effective solutions associated with problematic soils. Various additives including cement, lime, gypsum, fly ash, and bitumen were being in use as soil stabilizer. With upsurge in the need for environmentally friendly and sustainable materials, researchers have been investigating alternative materials for soil stabilization. Biological approaches have recently been developed for improving the properties of soil. Biopolymers are produced from living organisms and are considered to be environmentally friendly soil stabilizers. An elaborate study on stabilization of soil using guar gum biopolymer was carried out through intensive laboratory experiments. Two soils, low plastic (CL) and high plastic (CH) clays were treated with different percentages of biopolymer (1%, 2%, 3% and 4%) by weight of dry soil. The experimental program mainly focused on compaction characteristics, unconfined compressive strength, California bearing ratio and one-dimensional swell potential tests. All the samples were prepared on dry mix basis. The UCS of cured and soaked samples was tested after 0, 2, 7, 14 and 28 days of curing and soaking. Strengthening effect of guar gum biopolymer was observed with increasing biopolymer content and curing time. A significant improvement in UCS of low plastic and high plastic soil was observed at 2% biopolymer at end of the curing period. The results indicated a substantial improvement in the CBR of both low plastic and high plastic clays under soaked and unsoaked conditions. Evidently, the use of guar gum biopolymer has shown significant improvement in geotechnical properties of low plastic and high plastic soil and can be identified as potentially sustainable alternative material for the stabilization of soil.