The effects of reduced paste volume in Portland limestone cement concrete

In Portland cement concrete, a high content of cementitious materials can cause early cracking. This study investigated the effects of minimised paste volume in structural concrete made with Portland limestone cement and blended aggregates (BA). The effects of using different types of cement and paste volumes were compared. It was found that concrete made using type IL cement (containing 14% limestone powder) showed comparable performance to concrete made with type I/II cement. Based on the results of laboratory testing and numerical modelling, the performance of concretes with different paste volumes was evaluated. The results showed that the paste volume could be reduced by around 27% without affecting the properties of the concrete. Using the BS technique, the paste volume could be further reduced by 24%. Concrete mixes prepared using the BA technique were found to have better potential performance than the reference concrete. It was concluded that the use of type IL cement and BA can effectively reduce the initial cost and carbon dioxide emissions of structural concrete without loss of performance.