Date of Award

1-4-2024

Document Type

Thesis

School

School of Civil Engineering

Programme

Ph.D.-Doctoral of Philosophy

First Advisor

Sujatha E Ramani

Keywords

Biopolymers, Geotechnical, Flexible Pavement Design, CBR, UCS

Abstract

Cognizing the contamination effects of chemical soil modifiers on soil and groundwater, the assessment of the ability of biopolymers to improve the engineering properties of soils has gained attention in the last decade. As a soil additive, biopolymers have the potential to solve the trilemma of sustainability, price and soil suitability. Two polysaccharides and two protein biopolymers have been adopted in this study to enhance the geotechnical properties of fine-grained soils.

Design thickness catalogues were developed for a three-layered flexible pavement using 3D finite element analysis (FEA) and layered elastic analysis. The catalogue aims to provide structurally reliable thickness values for stabilized soils possessing varying CBR.

Thickness optimization is achieved by limiting the damage ratio of the mechanisticempirical design. The analyses were performed for the biopolymer-treated fine-grained soils with varying traffic intensities based on mechanistic-empirical design philosophy conforming to IRC: 37-2018. Genetic programming (GP) was employed to obtain equations governing the rutting and fatigue failure in pavements.

Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), average particle size determination, and adsorption studies of the treated soils revealed the mechanism of strength improvement of the fine-grained soils. The savings in cost for a 1 km stretch of the pavement were estimated to be 14.15%.

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