Bio-Mediated Soil Stabilization for Enhanced Infrastructure Resilience — 71a — Ishika Garg¹, Rimjhim Sharma¹, Tanvi Govil², Rashed Rahman³, Tejo V. Bheemasetti³, Bret N. Lingwall⁴, and Rajesh K. Sani^1,2

¹ Department of Chemistry, Biology, and Health Sciences, South Dakota Mines, Rapid City, SD, USA

² Karen M. Swindler Department of Chemical and Biological Engineering, South Dakota Mines, Rapid City, SD, USA 

³Department of Civil & Architectural and Engineering Mechanics, University of Arizona, Tucson, Arizona 85721

⁴Department of Civil and Environmental Engineering, South Dakota School of Mines, Rapid City, South Dakota 57701

In the United States, addressing the detrimental effects of freeze-thaw phenomena on highway infrastructure alone costs approximately $2 billion annually. Frost-heave and thaw-weakening pose significant challenges to civil infrastructure in cold regions. Psychrophiles have evolved a range of adaptations to cope with the stresses imposed by freeze-thaw cycles. Through this work, we present the application of a Biopolymer produced by a psychrophilic bacterium, to stabilize frost-susceptible (FS) soil. The Biopolymers been acknowledged in literature to display antifreeze properties, including water retention, nutrient and ion sequestration, and osmoregulation, thus enabling bacteria to prevent ice crystal formation in soils. Therefore, we propose that these properties of Biopolymer could also stop frost-susceptible soil from freezing. To achieve this, the biopolymer was extracted from a psychrophilic bacterium cultivated at varying temperatures: approximately 8 days at 25°C and 30 days at 4°C. The extraction yielded around 2.900 mg/ml of the Biopolymer at 25°C and 2.200 mg/ml at 4°C from the growth medium (Tryptic Soy Broth). The extracted Biopolymer was combined with FS Soil to examine it for antifreeze properties under a microscope. The thermal properties like freezing, thawing, and thermal hysteresis of the control and treated soils are evaluated using a thermoelectric cooling system. The results of the study indicate that the Biopolymers can reduce frost-induced damage in civil infrastructure, potentially leading to a sustainable and cost-effective solution to this ongoing issue.

Keywords: Bio-mediated soil stabilization; Biopolymers; Freeze-thaw cycles; Psychrophilic bacteria

South Dakota School of Mines & Technology
Dr. Rajesh Sani