Title: Interaction of Superplasticizers with Calcium Aluminate Cements
Author(s): H. Fryda, V. Gachet, P. Bost, and K. 1. Scrivener
Publication: Symposium Paper
Appears on pages(s): 91-100
Keywords: admixture (accelerating); cement (calcium aluminate); superplasticizer
In the absence of admixtures, the workability of calcium aluminate cement (CAC) concretes is similar to that of Portland cement concrete. However, the classic types of superplasticisers for Portland cement concrete, lignosulphonates and polynaphthalene sulphonates, have only a modest effect on the workability of concrete made from calcium aluminate cements. Consequently, the placement of CAC concretes at water to cement ratios below about 0.4 can be difficult and necessitates the use of a high cement content (1, 2) . In contrast, a ‘new generation’ superplasticisers (poly carboxylate polyox) has been found to be highly effective in improving the rheology of calcium aluminate cement concrete. If used alone they can also severely retard the setting time, but this effect can be overcome if they are used in combination with other admixtures. This paper discusses the effect of superplasticisers on the flow and setting time of CAC mortars.