Troisiéme Conférence Européenne sur les Matériaux et les Procédés Avancés
J. Phys. IV France 03 (1993) C7-1341-C7-1346
Possibilities of special cements in ceramic applicationsA. CAPMAS and T.A. BIER
Lafarge Fondu International, 157 avenue Charles de Gaulle, 92521 Neuilly-sur-Seine, France
About 25 years ago, the only way to have confinement material for high temperature applications was to prepare a ceramic by sintering or fusion at high temperature. A new technology came, with the production of Low Cement Castables. This new product was obtained by a careful choice of the granulometry of the aggregates, an optimization of the defloculation of fine particles, including the cement (Calcium Aluminate Cement) and the addition of silica fume. Silica fume brought two improvements : - a fluidifying effect, due partly to the low sensitivity of viscosity to pH, and partly to the geometric effect of the nicely spherical particle. - a chemical effect, brought by the reaction of silica and Calcium Aluminate Cement to give a coherent zeolithic structure, through which water could escape during the first firing. From a ceramist point of view, it is interesting to understand how this components, nearly colloïdal system mixed in water can be heated up to ceramization without any noticeable change in mechanical characteristics and shrinkage. From a more practical point of view, it is also interesting to realize that some characteristics, usually attributed only to ceramics, also apply with low cement castables technology : high compressive strength, flexural strength, corrosion resistance, abrasion resistance, impact resistance.
© EDP Sciences 1993