Possibilities to Control Concrete Shrinkage by Means of Chemical Admixtures

Abstract

The main object of the present paper is to describe the possibilities to control shrinkage of concrete by means of chemical admixtures. In an introductory part, also a general overview on the state of knowledge in the field of concrete shrinkage is given. The actual experience indicates that the control of concrete shrinkage with the traditional plasticisers and superplasticisers is quite limited, despite the water reduction obtained at same concrete consistency. A decrease in concrete shrinkage in the order of 30% is, however, possible by the addition of special shrinkage-reducing admixtures. The use of sulfoaluminate-based expansive admixture allows in principle to compensate completely the shrinkage of concrete. An effective means to improve the shrinkage compensating effect is the combination of the expansive admixture with a shrinkage-reducing admixture.