Rice Husk Ash Concrete Blocks
Rice Husk Ash Concrete Blocks The compressive strength of some commercial sandcrete blocks in Minna, Nigeria was investigated. Rice Husk Ash (RHA) was prepared using Charcoal from burning firewood. Preliminary analysis of the Constituent materials of the ordinary Portland Cement (OPC) / Rice Husk Ash (RHA) hollow sandcrete blocks were conducted to confirm their suitability for block making. Physical test of the freshly prepared mix was also carried out. 150mm×450mm hollow sandcrete blocks were cast cured and crushed for 1, 3, 7, 14, 21, and 28 days at 0, 10, 20, 30, 40 and 50 percent replacement levels. Test results indicate that most commercial sandcrete blocks in Minna town are below standard. The compressive strength of the OPC/RHA sandcrete blocks increases with age at curing and decreases as the percentage of RHA content increases. The study arrived at an optimum replacement level of 20%.
From the tests conducted on OPC/RHA hollow sandcrete blocks as presented in the various sections, the following conclusions are made:
- The rice husk ash produced using charcoal from firewood is pozzolanic and therefore is suitable for use in block making;
- The Specific gravity, Uncompacted bulk density, and Compacted bulk density of rice husk ash were found to be 2.13, 460 Kg/m3 and 530 Kg/m3 ;
- For a given mix, the water requirement increases as the rice husk ash content increases;
- The setting times of OPC/RHA paste increases as the ash content increases;