High-strength aluminate cement produced by cold isostatic pressing

High-strength cement was obtained by a simple process technique. Powders of Secar 71 were cold isostatically pressed (CIP) into green bodies with a re lative density of 66 vol%. The green bodies were then immersed in water or kept in humid air for curing at various temperatures for different periods of time. Hydrated cements with high density and low porosity were obtained. The water uptake was more than 20% (by weight) after one day. Over the cou rse of a few days the open porosity decreased to a few per cent. The three- point bending strength of the hydrated cement bodies was 50-80 MPa, and the compressive strength exceeded 200 MPa. The hardness measurement revealed a twofold increase, compared with the control specimens which were prepared by the conventional mixing method. The microstructure of the CIP-processed cements showed a macropore-free composite structure. It was concluded that, by applying CIP, high-strength cement could be produced using commercially available cement without any auxiliary additives. (C) 2000 Kluwer Academic Publishers.