COMPRESSIVE STRENGTH ANALYSIS OF CONVENTIONAL DESIGN CONCRETE MIX RATIO; 1:2:4 AND NON-CONVENTIONAL CONCRETE MIX RATIO; 1:3:3 FOR THE CONSTRUCTION INDUSTRY IN NIGERIA

The challenge which is very common in Nigeria construction industry is the coarse nature of 1:2:4 conventional mix ratio of green concrete. Most often in Nigeria construction industry, the 1:2:4 conventional mix ratio is often been rationalised and batch to obtain 1:3:3 mix ratio so as to have a workable green concrete. This is often preferable due to the challenge arising from inability of the quarry industry to crush stone 10mm, 12mm, 14mm and 20mm size separately. What is common in many part of this Country is manual crush aggregate, which is hand crush aggregate which are the combination of 10mm, 12mm, 14mm and 20mm, which lead to the difficulty in concrete batching with 1:2:4 mix ratio. This research came from the challenge encountered during the construction of Oba Abegunde Adukanjemeji Monument Dynast, Omu Aran, in getting machine crush aggregate, For the purpose of this research work, the compressive strength of concrete made of conventional mix ratio (1:2:4) and concrete made of non-conventional mix ratio 1:3:3 was investigated. Combination of 10mm, 12mm, 14mm and 20mm size of coarse aggregate was use to cast concrete made of 1:2:4 mix ratio and 1:3:3 mix ratio. The concrete cube of size (150mmx150mmx150mm) made from 1:2:4 mix ratio serve as the control and was cured in a curing tank which was monitored for 7days, 14days and 28days respectively. Also concrete cube made of 1:3:3 mix ratio was also cast and cured for 7days, 14days and 28days respectively. From the result of the average compressive strength of concrete made of 1:3:3 mix ratio, at twenty eight days of curing gives(16N/mm2 ), which shows that, the concrete strength met the minimum required standard for twenty eight days of curing which is (15N/mm2 ) while 1:2:4 mix ratio using the same aggregate and curing period gives (17N/mm2 ) Also a statistical test (Analysis of variance, ANOVA) on the data gotten was introduced in which a null hypothesis and alternative hypothesis was proposed, and the null hypothesis was accepted as a result of the asymptotic significance value gotten to be (0.923). This shows that 1 there is no significant difference between concrete made of 1:2:4 mix ratio and the one made from 1:3:3 mix ratio