Induration of laterites in tropical areas: Assessment for potential structural applications

Indurated lateritic blocks (yellow-brown and red) were collected from two deposits in Yaounde, Cameroon for investigation as structural building and construction materials. Dimensioned blocks were characterized using XRD, DTA/TGA, mechanical compression, water absorption and porosity tests, and examination by optical and electron microscope. Water absorption values, pore size distribution and cumulative pore volume were used to compare indurated laterites with fired day-based bricks. Atmospheric exposure of the test specimens resulted in progressive strengthening of the matrix and transformation of yellow areas to a browner colour. This confirms other observations in the literature which describe induration as the transformation of goethite to hematite with red matrix as the end step and most stable laterite form. Presence of larger size pores and significant pore-to-surface area ratio negatively affect the material's compressive strength. However, due to stability in water, blocks with significant phase distribution and amorphous interlinking are suitable as structural building and construction materials.