Abstract: In this study, the effect of exposure of cement on the compressive strength of concrete was investigated. The compressive strength of concrete with different cement exposure time and conditions and the limiting exposure time of cement beyond which cement should not be used in structural concrete production were determined. The fresh cement as well as cement exposed to two conditions (warehouse and open-air exposure) for different durations (6, 12, 18, 24 and 42 Hours) was used in the production of concrete with target strength of 30 N/mm2. Slump and compressive strength tests were carried out on the various samples produced using the two types of cement and it was observed that the compressive strength value of concrete constantly reduced from 29.13N/mm2 for the control sample (No cement exposure) to 17.28N/mm2 and 13.90N/mm2 for 42 hours cement exposure in Warehouse and open-air exposure conditions respectively. A regression model was also developed to predict the compressive strength of concrete and the percentage loss in compressive strength with increase in exposure time for the both conditions. The limiting exposure value was found to be 16.66 Hours and 10.45 Hours for warehouse and open-air exposure respectively. It was also observed that there was a considerable reduction in the compressive strength of concrete with increase in exposure time of cement and the rate of loss of strength of concrete with exposure duration varied for the different exposure conditions. It was also observed that the workability of concrete was not affected by the exposure condition of cement.
Keywords: Compressive strength, exposure time, warehouse exposure, open-air exposure, regression model, target strength.
Title: EFFECT OF EXPOSURE OF CEMENT ON THE COMPRESSIVE STENGTH OF CONCRETE
Author: Nwofor T.C., Sule S.
International Journal of Civil and Structural Engineering Research
ISSN 2348-7607 (Online)
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