Rheological behaviour of fresh cement pastes: Influence of synthetic zeolites, limestone and silica fume

New generation concretes have specific properties, often obtained by using additives, and these properties are strongly affected by rheological characteristics of the fresh cement paste. In this work small amplitude oscillations were adopted to investigate the effects of synthetic zeolite, limestone and silica fume on the theological properties of fresh pastes. Time sweep tests were used to describe paste evolution with time evidencing that zeolite is more able to increase the rate of structure development with respect to other additives. Frequency sweep tests evidenced that zeolite, at least at low concentration, is able to improve the mechanical strength and to increase the liquid-like behaviour of the paste. Adopted theological tests and data analysis are suitable to describe paste structure and evolution with time and synthetic zeolite seems able to give better properties to cement paste than other additives can. (C) 2014 Elsevier Ltd. All rights reserved.