A Review on the Fundamental Engineering Properties of Compacted Laterite Soil at Different Gradations

Abstract

Laterite soils are occasionally associated with geotechnical problems such as road deformation, erosion, settlement, dam seepage, slope instability, leachate permeation through hydraulic barriers, etc. Numerous soil improvement techniques were being applied to overcome these problems, including mixing the laterite soil with cements, limes, bitumen, chemicals, pozzolanas, etc. These additives may not be locally available and cheap, and could significantly increase the cost of construction. Likewise, in many cases, these stabilizing agents are not environmentally friendly. Different percentages of fines, sand and gravel in laterite soils exhibit different engineering characteristics and behaviour, making it difficult to obtain suitable and appropriate gradation for specific construction purposes. Thus, the essence of this review is to determine the fundamental engineering properties of laterite soil as a standalone material at different gradations to harness its potentiality for various construction purposes. It proposes step-by-step procedures on how to achieve a better soil by varying its gradation and moisture content. Laboratory testing in accordance with BS1377:1990 and ASTM D698 are adopted to examine the engineering characteristics with respect to hydraulic conductivity, shear strength, and volumetric shrinkage. In this experimental technique where molding water content and compaction energy are carefully controlled at different laterite gradations, the engineering design is anticipated to provide greater accuracy, safety, and sustainability.