Understanding the impact of laboratory and field curing conditions on the strength properties of black cotton soil treated with Xanthan Gum and Guar Gum Biopolymer

Abstract

ABSTRACT A sustainable solution to stabilise the expansive soil over cement stabilisation is needed to avoid the negative environmental impact. Therefore, in this study, two biopolymers (such as xanthan gum and guar gum) were used to stabilise the expansive soil, and the study focused on the impact of curing (field and laboratory curing) conditions on the performance of biopolymer stabilisation. The compressive strength results showed that the treated sample achieved a higher strength up to 4.18 times with XG than the untreated soil sample strength with 28 days of curing (in FC) with 1.5% of the weight of the soil sample with both biopolymers. Conversely, the sample cured in LC was observed to have a very low strength increment, and the gained strength was lost with the curing period from 7 days to 28 days. The possible reason behind this phenomenon is that in moist conditions, the biopolymer presence in the hydrogel form reduces the soil particle interaction, and it is also due to the breakage of the soil-biopolymer matrix. The swelling pressure of the soil was significantly reduced compared to untreated soil. The microstructural and element composition analysis confirmed that the biopolymer treatment is not involved in any cementitious reaction.