Comparative Study of the Compressive Strength of Cement Laterite Brick Produced with Rice Husk Ash and Wood Ash as Partial Replacement Of Cement
The paper presents an outcome of experimental comparative study on the compressive strength of laterite brick made with rice husk ash and wood ash as partial replacement of cement. First, Rice Husk Ash (RHA) and Wood Ash (WA) were prepared and subjected to the following tests: specific gravity, density and bulk density. This was followed by the production of three types of bricks viz cement laterite-bricks(control), cement-laterite bricks produced using RHA as partial replacement of cement and another brick made with WA as partial replacement of cement. Replacement levels range from 0 - 30% at 10% intervals. The samples were cured by water sprinkling, before testing them for compressive strength at 7, 14, 21 and 28 curing days. Result of the tests showed that the specific gravity of RHA and WA are 2.20 and 2.13 respectively. The Absorption capacity of all the samples is in the range of 4.5 – 9.1%which is within the allowable value of 25% set by the Nigerian Industrial Standard. Compressive strength for 10 % replacements range from 0.75N/mm2 for 7days to 3.7N/mm2 for 28 days for RHA, as against 2.6 N/mm2 for 7days to 5.3N/mm2 for 28days curing for WA. This shows that bricks produced using WA are relatively higher in strength than those made with RHA. Though it is concluded that RHA and WA, can be used as partial replacements of cement in the production of laterite brick. Also, laterite brick produced with 20% and 30% partial replacements of cement with RHA and WA, respectively,, have, satisfied the minimum requirement as contained in BS 6073, and are recommendable.
Keywords: Cement, compressive strength, rice husk ash, laterite brick, partial replacement levels, wood ash.