Abstract:
The large amount of space taken on landfills by waste, the constant release of environmental polluting gases like CO 2 into the atmosphere and the high cost involved in cement production has led to the search for alternative binding materials that are cheap, ecofriendly and which will help waste management. This research evaluates the effect of calcium carbide residues (CCR) on the performance of wood ash (WA) and animal bone powder (ABP) partially replacing cement in concrete. The mix ratio used to cast 216 concrete cubes of dimension 150 mm x 150 mm x 150 mm were 1:2:4 and 1:3:6 mixes. The percentage replacement of cement with CCR/ABP and CCR/WA were 0%, 5% 10%, 15%
and 20% (by weight of cement) respectively. The water/cement ratio was kept at 0.55, setting time, workability, slump of concrete, compacting factor and compressive strength were determined. After 7, 14, 28 and 56 days of curing, the cubes were subjected to compressive tests to determine the
characteristic strength of the concrete using standard procedure. The compressive strength of concrete increased as the age of curing increased, but decreased with increase in percentage replacement for both mixes. The result achieved was used to determine the mix that produced the highest strength at
7 th , 14 th , 28 th and 56 th days respectively. The strength values obtained after 28 and 56 days curing, shows that the compressive strength (19.6 N/mm 2 and 21.3 N/mm 2 ) of 5% CCR/ABP mix is the best mix with strength greater than conventional concrete strength (17.9 N/mm 2 and 19.2 N/mm 2 ) at mix
ratio 1:2:4, while the compressive strength (14.3 N/mm 2 and 15.8 N/mm 2 ) of 10% CCR/ABP mix is the best mix with strength greater than conventional concrete strength (12.3 N/mm 2 and 14.2 N/mm 2 ) at mix ratio 1:3:6. Analysis of variance was performed to further determine the optimal mix, and from
this, it was shown that there is a significant difference between the strength of 5% CCR/ABP and 10% CCR/ABP when compared with other percentage replacements at 1:2:4 and 1:3:6 mixes. This research therefore established that, CCR/ABP can be used for partial replacement of cement up to 5% for 1:2:4
mix and 10% for 1:3:6 mix with improved workability and compressive strength of concrete
