The effect of differences in the composition of Portland cement on the properties of hardened concrete

Abstract

The effects of differences in the composition of Portland cements on the properties of concrete have been investigated using three cements in which the C3S (i.e. 3CaO · SiO2) contents ranged from 33·5 to 67%. It was found that the composition of the cement did have an effect but not as great as did differences in the curing regime. The concretes made with the higher C3S/C2S ratio cements had properties which were as good as, or in some respects superior to, those made with cements with a low C3S/C2S ratio. In good curing conditions the differences were not marked but in adverse curing conditions the faster hydration of the higher C3S/C2S ratio cements were a definite advantage and concretes made with these cements performed better in almost every respect. The results suggest that concerns about the reduced durability of concrete specified by strength, and therefore containing a lower cement content or higher water/cement ratio when a high strength cement is used, may have been over-emphasized. However, it should be noted that the effects of differences in heat release have not been assessed in this study.