Investigation of laterite stones for building purpose from Malabar region, Kerala, SW India - Chemical analysis and microstructure studies

This study reports on the chemical and microstructural analysis of laterite from four different quarries for building purposes from Malabar region in Kerala in the south west of India. Wet chemical analysis was performed to determine the amounts of the various oxides present, while the microstructural characteristics such as mineral composition, texture and structure were analysed using advanced instrumental techniques such as polarized petrographic microscope, X-ray diffraction analysis and scanning electron microscopy. An attempt was made to understand the link between physico-mechanical characteristics and the chemical composition and microstructure. The study revealed that high strength laterite was abundant in heavier minerals like hematite and goethite and was marked by dense and continuous crystalline matrix, whereas low strength laterites were abundant in clay minerals (mainly kaolinite), and showed a scattered distribution of iron minerals. In terms of chemical composition, the differences between the four types of laterite were not significant.