Laboratory Investigation of Biological and Chemical Stabilization of Sandy Soil in the Presence of Fine-Grained Soil

Document Type : Research Article

Authors

1 Shahrood University of Technology/ Faculty of Civil Engineering

2 Damghan University/ Faculty of Technology and Engineering

10.22060/ceej.2026.23805.8224

Abstract

Chemical stabilization of soil is a widely used method for improving the geotechnical properties of problematic soils, such as increasing bearing capacity and reducing permeability. Recently, environmental concerns related to this method have led researchers to use more environmentally friendly methods. In this study, the performance of biopolymers, guargum and xanthangum, as biological stabilizers was compared to chemical stabilization using cement and lime. Unconfined compressive strength(UCS)tests were conducted on sand samples mixed with varying percentages of kaolin clay(0, 10, 15, 20, and 25% by weight). The samples were stabilized using different concentrations of guar gum and xanthan gum(0.5%, 1%, 1.5%, and 2% by weight), as well as cement(5%, 10%, and 15% by weight) and lime (4%, 6%, 8%, and 10% by weight). The effect of curing time(7, 14, and 28 days) on the compressive strength of the stabilized samples was also evaluated. The results revealed that increasing the concentration of cement, guargum, and xanthangum improved the compressive strength, whereas for limestabilization, the maximum strength was observed at an 8% lime content. Additionally in samples stabilized with guargum and xanthangum, increasing the concentration and curing time led to an increase in compressive strength, such that guargum performed better than xanthangum. The use of biopolymers significantly enhanced the unconfined compressive strength of the soil and could serve as a viable alternative to chemical stabilizers. However the results indicated that in biologicalstabilization, while increasing clay content and additive concentration enhanced the strength, the rate of strength improvement decreased as the clay percentage increased

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