DRY AND WET PROPERTIES OF RICE HUSK CONCRETE VARYING WATER TO CEMENT RATIO AND COMPACTION PRESSURE

Abstract

The study was undertaken to evaluate the wet and dry properties of rice husk concrete with varying water to cement ratio and compaction pressure. The pressure required to crush the concrete was determined and varied at intervals ranging from 15kN, 75kN, 150kN, 225kN and 300kN with water to cement ratio ranging from 0.4, 0.45, 0.5, 0.55, 0.6 and 0.65. Sand was used to partially replace rice husk in an increasing order of 7.5%, 15% and 22.5% by weight of sand. The rice husks concrete were subjected to testing. Test conducted on the aggregates was sieve analysis test and specific gravity test while test conducted on the rice husk concrete was water absorption test and compressive strength test. Results obtained from sieve analysis test suggest that sand and granite was classified as A-2-4 and A-1-b according to AASHTO Soil Classification System, SM and SC according to USCS Soil Classification System. Water absorption test results conducted on the rice husk concrete cubes revealed that the water absorption of the concrete increased with addition of rice husk but decreased with increase in compaction pressure, results obtained from compressive strength test of the hardened rice husk concrete cubes revealed that the hardened density and compressive strength decreased with increase in rice husk but increased with increase in compaction pressure. Assessment of the effect of water to cement ratio on the hardened density and compressive strength of the concrete revealed that the hardened density and compressive strength increased from 0.4 water to cement ration to 0.55 water to cement ratio beyond water to cement ratio of 0.55, the hardened density and compressive strength of the concrete decreased. The study recommended the use of 7.5% rice husk as effective quantity for production of light weight concrete.