Abstract
The urge to find alternative materials to existing conventional ones and the need to improve the strength of
sandcrete blocks have compelled researchers to intensify work on substitutes to cement with a view to
investigating their usefulness wholly as a construction material or partly as a substitute for cement in sandcrete
blocks. This project investigates the possible use of coconut husk ash (CHA) as a partial replacement of cement
in sandcrete block production. 140 numbers of 450mmx150mm×225mm hollow sandcrete blocks of mix ratio
1:8 were cast, cured and crushed at 7, 14, 21, and 28 days. The coconut husk ash was replaced at 0 to 30
percent levels at 5% intervals. The maximum compressive strength of 2.10 N/mm2 was recorded at 5%
replacement at 28th day. The compressive strength of the ordinary Portland cement /coconut husk ash sandcrete
blocks generally decreases as the percentage of coconut husk ash content increases. The maximum value of
2.10N/mm2 for the 5% replacement level is found suitable and recommended for building construction having
attained a 28-day compressive strength of more than 2.0N/mm2 as required by the Nigeria National Building
Code (2006) for non load bearing walls.