Use of broken and unbroken black African Olive seed as partial replacement for coarse aggregate in concrete.

Abstract

An experimental study on the compressive strength of concrete using broken and unbroken black African olive seeds (BAOS) as partial replacements for coarse aggregate in concrete production is presented. Preliminary tests such as slump, impact factor, sieve analysis of aggregates and workability of the fresh concrete among others were conducted. The percentage replacement of BAOS was varied from 0 %, 5 %, 10 %, 15 %, 20 %, 25 % and through 30 % while mixing the concrete in the ratio 1:2:4 with a water/cement ratio of 0.5. A total of 140 concrete cubes specimens for both broken and unbroken BAOS of 150 mm x 150 mm x 150 mm sizes were cast and cured for 7 days and 28 days respectively. The result shows that at 28 day curing, maximum compressive strength of concrete for broken BAOS percentage replacements is found to be 19.46 N/mm2, but a little lower than the control (19.90 N/mm2), while that of unbroken BAOS is 20.70 N/mm2a little higher than the control (19.90 N/mm2) all at 28 day curing. The results suggest an increase in compressive strength only for unbroken BAOS. It shows that both broken and unbroken BAOS concrete appear to belong to light weight concrete with percentage replacements up to 15 % for unbroken BAOS and 10 % for broken BAOS by maintaining a compressive strength of concrete 17 N/mm2 and above as required by the British Standard.