EFFECT OF RICE HUSK ASH IN THE PRODUCTION OF HOLLOW SANDCRETE BLOCK
The effect of rice husk ash as a component of hollow sandcrete blocks was investigated. The objective was to reduce the present high cost of building construction. The rice hush ash used was derived from rice husk which is a bye-product of milling rice. Batching of the material was done by weight and a nominal mix proportion of 1:6 of cement and sand respectively was used. One hundred and twenty samples of hollow sandcrete blocks were produced in two different sizes 226x225x450 (mm) and 150x225x450(mm). Various proportions of rice husks ash i.e. 0%,4%,10%,20%, and 30% were used as replacement of cement in the mix. The compressive strength of the samples were determined after 28days using the universal testing machine and the average values obtained were 2.8, 2.2, 2.5, 2.0, and 1.7(N/mm2) respectively. It was concluded that rice husk ash blocks have relatively lower strength compared to blocks without rice husk ash. At 10% ash replacement however, the hollow block developed compressive value of 2.5N/mm2 which met the minimum standard required for building construction. Cost analysis showed that a saving of 5.3% per block can be achieved through the use of rice husk ash blocks. It was therefore recommended the rice block ash blocks with up to 10% replacement can be used in building construction for non-load bearing walls such as fence walls and partitions.