Physical Properties of Sandcrete-Laterite Blocks

The incorporation of laterite in sandcrete blocks production is a common commercial practice in Nigeria. However, proper calibrations as per optimal mix proportions of these aggregates to give blocks that meet minimum requirements by various standards are lacking. In this study, a mix ratio of 1:8 (cement: aggregates) and a water-cement ratio of 0.5 was adopted at different percentages of laterite replacing sand. Block sizes of 450 x 225 x 150mm were used. Curing was done for 3, 7, 14, and 28 days. A total of 104 blocks were prepared and tested for density, compressive strength, static modulus, water absorption and thermal conductivity. Results showed a decrease in density, compressive strength and thermal conductivity values with the addition of laterite. On the other hand, the water absorption of sandcrete-laterite blocks increased, as the blocks became more permeable. The decrease in thermal conductivity indicates better insulating properties of the Sandcrete-Laterite Blocks. These blocks will, therefore, reduce the energy requirements in a building. The study recommends an optimal replacement level of 10% of sand with laterite which gave a strength of 1.87N/mm2 and is 6.9% greater than the minimum requirement of 1.75N/mm2 by the Nigerian Building Code for individual blocks.