Models for Prediction of 28-Day Concrete Compressive Strength

The design codes usually specify 28-day concrete compressive strength as design strength for reinforced concrete (RC) structures. Concrete specimens are cast and tested at 28 days to ensure compliance of concrete strength with the design requirements. Prediction of concrete strength can help in reducing waiting time and can result in speeding up construction activities. This paper presents prediction models for concrete compressive strength up to 28 days. The data of experimentally tested concrete cylinders were employed in the development of these models. The effects of cement chemical composition and fineness were included by defining two parameters in the models. The predictions are based on 7-day concrete strength. The proposed models provided good correlation with the observed concrete strength data. The models were also validated using the strength results of concrete mixes in the available literature. Generalized forms of the models have been suggested for cement brands available in Pakistan.