Rheological properties of micromortars containing fines from manufactured aggregates

This paper concerns the influence of fines from manufactured aggregates on the rheological properties of the micromortar phase of concrete. Fines from nine different aggregates were included in the experimental work. The zeta potential of five of them was measured at different additions of superplasticizer in order to study the interaction between the surface of the fines and the superplasticizer. The rheological properties of the micromortars were studied at different volume concentrations of fines and at different concentrations in the paste phase, i.e., w/c ratios. Furthermore, the micromortars were studied at different dosages of a superplasticizer. The results show that the fines have different surface properties, i.e., zeta potential, and indicate that the superplasticizer only is adsorbed on some of them. The results from the rheological characterisation of the micromortars indicate that the higher water demand of concrete with manufactured aggregates partly can be traced to the properties of the micromortar phase of the concrete.[PUBLICATION ABSTRACT]