Abstract: The characteristics of surfaces of bodies made from a basic material (22) which is mouldable at low temperatures, such as concrete or concrete-like materials are improved by applying a layer of metal (12) to one or more surface parts thereof. The metal layer may be applied by moulding the basic material, optionally with reinforcements (23) against a prefabricated metal member (12) which may be a metal layer formed on a surface (21) of a model or a mould (20) whereby a metal-coated tool for casting or shaping articles corresponding to the model or mould may be made from the basic material.The mouldable material is, in particular, a material which in its cured state comprises a coherent matrix, the matrix comprising(A) homogenously arranged solid particles of a size of from about 50 .ANG. to about 0.5 .mu.m, or a coherent structure formed from such homogenously arranged particles, and(B) densely packed solid particles having a size of the order of 0.5-100 .mu.
Abstract: A dry cement composition containing an amount of ferrous sulphate (FS) for eliminating or substantially reducing the content of water-soluble chromate, is produced by grinding a starting material (C, G) in a cement mill, and the ground cement material is passed from the mill to a storage container (33) The ferrous sulphate in an amount of 0.01-10 and preferably 0.4 percent by weight is added to and mixed with the starting material in a dry or non-dissolved condition at a location or at locations upstreams of the storage container (33). The ferrous sulphate is preferably added to the starting material upstream of the cement mill.
Abstract: Steel articles are protected against corrosion by being completely or partially coated with a material showing a resistivity of at least 0.1 M.OMEGA..cm and comprising a matrix which comprises(A) inorganic solid particles of a size of from about 50 .ANG. to about 0.5 .mu.m, or a coherent structure formed from such homogeneously arranged particles, and(B) densely packed solid particles having a size of the order of 0.5-100 .mu.m and being at least one order of magnitude larger than the respective particles stated under (A), or a coherent structure formed from such densely packed particles, the particles B preferably being Portland cement particles.Particles A are preferably ultrafine silica particles formed by growth from vapor phase and are substantially densely packed in the voids between the particles B. Particles A are especially present in an amount of 10-30% by volume, calculated on the combined volume of the particles A+B.