PARTIAL REPLACEMENT OF ORDINARY PORTLAND CEMENT (OPC) WITH COCONUT HUSK ASH (CHA) IN SANDCRETE BLOCK PRODUCTION

Egbe O. Francis¹, G.L. Oyekan², Ezugwu O. Maryann¹.

¹Department of Civil Engineering, Igbinedion University, Okada.

²Department of Civil Engineering, University of Lagos, Akoka.

E-mail: francisegbe@yahoo.co.uk

Abstract

This research was conducted to develop new kinds of pozzolana from Agricultural wastes using Coconut Husk Ash (CHA) as a case study. Some experiments were conducted to determine the properties of CHA, mortar and sandcrete blocks having a certain percent replacement of Cement by this ash. Tests conducted include: Consistency test, moisture content test, slump test and compressive strength test. In addition, densities of the OPC/CHA sandcrete blocks were also determined.To determine the compressive strength, 150 x 225 x 450mm hollow sandcrete blocks were cast, cured and crushed for 7, 14, 21, and 28 days at 0%, 5%, 10%, 15%, 20% and 25% CHA replacement levels. Test results revealed that the compressive strength of the OPC/CHA sandcrete blocks increases with age and decreases as the percentage of CHA increases. The highest strengths at 28 days that met the NIS specification for non-load bearing sandcrete blocks were 4.19N/mm², 3.66N/mm² and 2.53N/mm² for 0%, 5% and 10% CHA respectively. The NIS specification for non-load bearing sandcrete blocks (150 x 225 x 450mm) is 2.5N/mm²_, hence this indicates that the replacement of cement with coconut husk ash in sandcrete blocks is relatively possible not exceeding 10%. The study therefore arrived at an optimum replacement level of 10%.

Keywords: Coconut Husk Ash (CHA), Ordinary Portland Cement (OPC), sandcrete blocks, compressive strength.