Evaluation of mechanical strength and physical properties of indurated laterite with regard to in situ characterization of lateritic profile

Abstract

The majority of the geotechnical studies on lateritic materials in different parts of the world including India was carried out from the viewpoint of soil characterization and was not particularly meant for indurated laterites. With due need, in this study, mechanical strength and physical properties of indurated laterites from an abandoned quarry of Kharagpur (India) were investigated with regard to in situ characterization of the lateritic profile. Based on texture, appearance and relative strength of the lateritic materials, a total of four horizontal/sub-horizontal zones (Zones 1–4) sequentially lying below a thin humus zone existing on the top of the profile were identified. The indurated laterites were found to be confined within Zones 1 and 2 and were used to determine uniaxial compressive, point load and Brazilian tensile strengths; effective porosity; dry density; vug volumetric percentage (a newly introduced index); and slake durability indices by adopting a modified methodology. The pattern of variation of all these parameters with regard to the sample depth was found to be broadly in agreement with the in situ characteristics of the laterite profile. The quality of the indurated laterites for construction purposes was also assessed. The point load strength proved to be the most useful/practical strength parameter in characterizing indurated laterites. Both vug volumetric percentage and slake durability indices were found to be much more efficient than effective porosity and dry density in estimating the point load strength. The reasons behind all important observations are also elucidated in this paper.