Chapter 12 - Improvement of shear strength of cohesive soils by additives: A review

Abstract

Industrialization and expansion of populated areas is the reason for the increase in dead load as well as live load; consequently, soil stabilization is required to strengthen the subsoil and road surfaces. The engineering performance of soil is enhanced by improving its properties, such as shear strength. Different techniques are used for this purpose; use of additives such as Rice Husk Ash (RHA) and Fly Ash (FA) is one of the major and unique suitable options for strengthening cohesive soil. The focus of this research is to investigate the methodology of soil stabilization through a qualitative and quantitative study; i.e., can the shear strength of soil be enhanced through the use of RHA and FA? The qualitative approach is based on a review of 25 major articles on these materials, while shear strength is quantitatively measured experimentally in a laboratory. This paper will determine the results after addition of these materials (RHA, FA) through certain techniques and with some potential recommendations consolidated through the unconfined compression test (UCS). The major findings of this critical research analysis – based on both the review study and the experimental study – are as follows: the optimum quantity of RHA and FA to use is 12%–16% and they enhance the shear strength of soil an average of 125% and help with soil balance by cultivating geo-engineering properties of soil.