Biopolymer-Modified Soil: Prospects of a Promising Green Technology

Abstract

The benefit from using admixtures in soil to improve properties was discovered in ancient times. Various admixtures such as straw, bitumen, lime, salts and pozzolans are conventional additions to soil, while cement, petrochemicals and bacteria are currently being increasingly used in an effort to improve and stabilize soil from both mechanical and chemical aspects. The conventional techniques which utilize cement, lime, petrochemicals, etc., cause significant environmental degradation. With environmental awareness for materials and methods used in ground improvement generally growing, the trend towards using biopolymers as admixtures is expected to increase. This paper gives the concept and theory of ground improvement technique which employs biopolymers and describes the practical application of these techniques. A number of studies have been conducted in the past decades to check the suitability of various biopolymers in improving soil properties. The effectiveness of biopolymers for soil stabilization in agricultural, construction and military applications has been recognized by many researchers. More efficient and scientific usage of these materials for soil improvement requires knowledge about interaction mechanisms involved in the modification of geotechnical properties of soil. Most of the studies in clay–polymer interaction are from the field of medical engineering, where clay particles are suspended in the colloidal form and macromolecules are attached to them in different ways. The fundamental mechanism in biopolymer–soil modification proposed by various researchers is also presented in this paper. The study reveals the prospects of this green technology in the current era of rapid deterioration of natural resources. Furthermore, the need for continuing research on a number of factors which controls the mechanism is suggested.