Compositions: coating or plastic – Coating or plastic compositions – Inorganic settable ingredient containing
Patent
1997-07-07
1999-02-09
Marcheschi, Michael
Compositions: coating or plastic
Coating or plastic compositions
Inorganic settable ingredient containing
106677, 106681, 106724, 106737, 106738, 106816, 106817, 106802, 106792, 106795, 106122, C04B 3800
Patent
active
058688307
DESCRIPTION:
BRIEF SUMMARY
This is a 371 application of International Application Number PCT/CH95/00277 filed Nov. 27, 1995.
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to a building and construction material consisting substantially of binding agents such as cement, and mineral filler materials, a method of producing the building and construction material and a method of reducing the degree of shrinkage in the building and construction material.
The present invention is a further development of European Patent Application EP 0 647 603 which is equivalent to U.S. Pat. No. 5,641,815 and in which a construction and building material, such as concrete is disclosed which includes uniformly dispersed micropores. These superfine pores have a diameter in the range of about 0.01.mu. to about 5.mu., whereby the individual pores are themselves closed.
In this way, it is possible to build structures and building parts with a substantial higher strength in comparison with common concrete. The pores include an amount of air which is conventionally included in concrete for anti-freezing effect but the concrete is stronger than conventional concrete.
The micropores are obtained by mixing the binding agent or reactive material, such as cement, with additives, such as tensides and water in a conventional mixer or in a high turbulence mixer, in order to be thereafter or directly mixed in one processing step in a conventional concrete mixer with the aggregate such as sand and gravel. In case no additives are used, a high turbulence mixer must be used. In case additives such as tensides are used, the mixing of the cement with water can proceed in a conventional mixer.
The inclusion of micropores finds specific application for the production of so called lightweight building materials, such as those containing lightweight filler materials, in that due to the increase of the strength of the concrete enclosing the filler materials, the finally resulting lightweight building material has a sufficient strength.
SUMMARY OF THE INVENTION
The object of the present invention is to provide building and construction materials in form of heavy building materials, such as heavy concrete or conventional concrete, including a reactive binding agent and mineral filler materials, with an increased strength and a small shrinkage.
According to the invention the building and construction material including a binding agent such as a reactive binding agent, includes filler materials such as preferably mineral filler materials which have no finest grain components <0.2 mm. By means of deleting these fine grain components it impossible to obtain degrees of shrinkage in the range of about 0.1-0.3 per mille. Such a small degree of shrinkage is desired in the technique of high stressed concrete (bridges, roofs, very elegant, slender structures, etc.) where high strength is needed without shrinkage cracks due to shrinking which would endanger the structure.
A great number of publications are known which represent precisely the opposite opinion. It is conventionally suggested to use concrete having high portions of powdery grains in order to obtain as small as possible degrees of shrinkage whereby an increased portion of fine grains and powdery grains is not judged to be detrimental. The climate to which the concrete is exposed to, and in exceptional cases the composition of the cement are mentioned as triggering influencing properties for the shrinkage of cementitious blocks, mortar and concrete. Keeping the concrete moist is also important.
Due to this prior art, it is surprising that a substantial reduction of the shrinkage can be obtained by reduction of the finest grain components in the filler material or aggregates, in the concrete. As already mentioned, it is required in accordance with the invention to remove at least fine and powdery grain components from the aggregate which have a diameter of <0.2 mm. It can, however, be also advantageous to even remove finest component portions of <0.5 or even > up to 1.0 mm from the aggregate.
REFERENCES:
patent: 4985080 (1991-01-01), Jung
patent: 5326396 (1994-07-01), Abdelrazig et al.
patent: 5584926 (1996-12-01), Borgholm et al.
patent: 5641815 (1997-06-01), Fehlmann
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