EFFECT OF CURING DELAY ON THE COMPRESSIVE STRENGTH OF CONCRETE Nura Hassan, Jibrin Umar, Mohammed Ya’u, & Hussaini Ausaja Amshi Department of Civil Engineering Technology, Federal Polytechnic Damaturu Email: Nura2108@yahoo.co.uk

Abstract

Curing is very vital in the production of strong and durable concrete. This research work investigates the effect of curing delay on the compressive strength of concrete. Mix ratios of 1:1.5:3 and 1:2:4 were prepared with two different water/cement ratios, that is, water/cement ratios of 0.5 and 0.6. A total of 240 cubes were cast, that is, 60 cubes each of 1:1.5:3 with water cement ratio of 0.5 and 0.6, and 1:2:4 with water cement ratio of 0.5 and 0.6. Curing ages of 7, 14, 21, and 28 days were used. However, curing delays of 0, 1, 2, 3, and 4 days were used in this piece of work, where zero curing delay is serving as the control. The work was carried out under very dry environmental condition with relative humidity ranging from 10 – 15%. The results showed that, compressive strength of concrete decrease with the increase in the duration of curing delay, but the effect reduce with the increase in curing period. However, the curing delays result to  irreversible loss of compressive strength of the concrete. The richer mixes have more resistance to loss of strength compared to lean mixes. The lower the water/cement ratio, the higher the resistance to loss in compressive strength caused by curing delay. It is therefore, recommended that concrete should be properly cured without delay to avoid loss of strength.