A study on the effects of cement-aggregate ratio with different sand gravel ratio on the strength of concrete hollow blocks

The study is concerned in designing the concrete mix, best suited to small scale method of production that will produce hollow load-bearing masonry units. There were several design mixtures of water, cement and fine aggregates, the total volume of which is equivalent to 4 cubic feet, the volume was proportioned 1:3 such that one part constitute cement and the other three constitute the fine aggregates. The aggregates were further proportioned to different percentages of sizes 3/8 inch crushed rock and finer aggregates that passes the said sieve. There was no initial basis for the amount of water to be placed so we started off with a 50/50 proportioning of the aggregates, take the water content of the aggregates into consideration and computed the amount of water that we placed. The sample mixtures were then molded into CHB\u27s using the small scale method of production. Further mixtures with increased amount of aggregates at constant amount of cement were made to find the greatest ratio that will satisfy the required strength as well as economic requirements..Several samples were then made from each mixtures, the average value of which is taken as the final results from compression tests using the Universal Testing Machine (UTM) at 7 days, 14 days and 28 days curing period