Flow behaviour of superplasticised cement pastes: Influence of silica fume

The incorporation of silica fume and superplasticisers is important and at times unavoidable in the production of high performance concrete in order to obtain superior mechanical and durability properties. The present work focusses on the study of the effect of silica fume on the fluidity, loss of fluidity with time and water demand of cement pastes incorporating a melamine-based superplasticiser. A temperature range of 5°C to 45°C is used for evaluating the flow properties. The results show that an increase in the ambient temperature can lead to a decrease in the fluidity when silica fume is incorporated, whereas the fluidity increases in the paste that does not contain this mineral admixture. Nevertheless, the loss of fluidity in pastes with silica fume shows trends that are similar to the plain pastes.