NO176959B - the casting - Google Patents

Abstract

A casting compound as a building material for use instead of cement-based concrete. The casting compound comprises sand, stone and any additives and materials, and is characterized by the fact that it contains anhydrite as a binder which, when water is added, causes the casting compound to harden and harden. properties of the concrete technology, such as virtually shrink-free concrete, concrete that can withstand extreme requirements with regard to compressive strength (35-80 N / mm), heat (up to 1450 ° C), oxides, acids, salts and acidic environments. It emits no harmful gases. Anhydrite-based concrete provides new and better adhesion properties to all types of substrates. It gives a very flat and hard surface and can be laid on tiles, carpets, old concrete etc. from 1 cm thick without cracking. From approx. 3 cm thick is the self-supporting, and can be laid as a floating floor.

Description

The invention relates to a molding compound as a building material for use instead of cement-based concrete.

Today, cement is mainly used as a base for concrete. However, the cement-based concrete has several disadvantages: Shrinkage in cement is approx. 0.3%. That is you have major problems with cracks/cracks in the concrete.

Cement-based concrete can only withstand temperatures up to

600°C

Cement-based concrete is not resistant to oxides

and acids.

Cement-based concrete emits harmful gases from 150°C. Cement causes chromium allergic eczema.

Cement-based concrete gives poor adhesion to complex

substrate.

Cement-based concrete gives lime penetration when colouring. Cement-based concrete cannot be laid in thin layers of 1-3 cm without cracking. Substrate must be blasted and

treated with epoxy.

Cement lime can cause serious burns. Cement-based concrete has poorer properties in damp conditions

climate than in a dry climate.

Cement-based concrete has limited properties for pumping.

The purpose of the invention is to provide a molding compound which is cast like ordinary concrete, but which does not have the above-mentioned disadvantages.

According to the invention, this purpose is achieved by a casting compound which includes sand, stone and any additives and materials, and which is characterized by the fact that it contains anhydrite as the only binding and hardening agent, which when water is added causes the casting compound to harden and become hard .

In a preferred embodiment of the invention, the binding and hardening agent is synthetic anhydrite.

The molding compound according to the invention provides new properties for concrete technology, properties that were not previously known: Virtually loss-free concrete.

Concrete with new and better adhesion properties for all types of substrates.

Concrete that withstands up to 1450"C.

Concrete that can withstand oxides, acids, salts and acids

environments.

Concrete that does not lose its properties in humid climates.

The invention will be described in more detail in the following in connection with some design examples and with reference to the drawing, which is a diagram showing the importance of the amount of water for the firmness.

As the molding compound according to the invention is a complete replacement for cement-based concrete, it has been given the designation anhydrite-based concrete.

When the binder anhydrite is added to water, it reacts chemically with part of the water and you get a mass that solidifies and hardens and becomes hard. When this hardening takes place in a mixture that also contains sand and stone, the individual grains of sand and stone will be retained in the anhydrite base which glues the whole thing together to form the building material anhydrite-based concrete.

Anhydrite is produced today in two ways, as natural anhydrite and synthetic anhydrite.

Natural anhydrite occurs in certain rocks as calcium sulfate CaS04. This gypsum-like rock is water-rich and has a varied content of humus.

To refine this anhydrite, it is fired at a temperature of up to 1500°C. The end product is an anhydrite that has been dried and cleaned of most of the humus.

One producer of synthetic anhydrite is Bayer Chemische Werke GmbH in Germany. This anhydrite is an anhydrous calcium sulphate CaS04 (CAS - No. 7778-18-9) which is a by-product from the production of sulfuric acid.

Synthetic anhydrite has the following specifications:

Form: powder

Colour: white

Combustible: no, pulverizes at 1450°C

Shrinkage: 0.05 mm/m°C

pH value: > 10 in aqueous suspension Degassing: emits no harmful gases.

The natural anhydrite will initially never be as pure and stable in quality as synthetic anhydrite and experience has shown that synthetic anhydrite is best suited as a binder in the molding compound according to the invention. However, it is expected that the quality of natural anhydrite will improve in the future.

An example of synthetic anhydrite is "Baukulan" anhydrite base. According to our tests, Baukulan is the best anhydrite base. It is supplied by the company Baukulan Mortelwerk GmbH. Seelenpfad, 3167 Vettweiss, Germany. They currently have the rights to Bayer's synthetic anhydrite binder AB20. The company Baukulan M6rtelwerk has so far only used this anhydrite base for the production of liquid screed. Our continuation of this base into concrete technology has brought completely new dimensions to areas of use for anhydrite. Known components have been combined into a new mixture, a concrete mixture that has given new and surprising properties.

Anhydrite-based concrete is cast like normal concrete. It is virtually waste-free and can be cast without reinforcement.

The recipe for 1 m<3> of ordinary anhydrite-based concrete is: 480 kg anhydrite, 1240 kg sand aggregate 0-2 mm, 400 kg stone aggregate 2-8 mm, and 170 1 water. This is particularly suitable for thin plaster, 1-5 cm cast-on. Here, cement-based concrete will crack.

Anhydrite-based concrete provides better adhesion to all types of substrates. It can be laid on tiles, carpets, old concrete etc. from a thickness of 1 cm. This cannot be done with cement-based concrete. From a thickness of 3 cm, the concrete is self-supporting, i.e. it can be laid as a floating floor on e.g. styrofoam and plastic. Anhydrite-based concrete is particularly suitable for use in the following areas: as thin plaster, 1-5 cm pour-on (cement-based concrete

cracks),

as leveling concrete for concrete element (floor),

as exterior concrete. Anhydrite as a base gives a much denser concrete. Tests have shown that synthetic anhydrite has approximately the same properties in a dry climate as in a humid one

climate, up to 94% relative humidity,

as quick-drying concrete, for rapid curing without

waste

as industrial concrete, concrete for extreme requirements in terms of

compressive strength, heat, acid, etc.

as lightweight concrete with aggregates of lava balls or leca balls,

as electric concrete for casting on heating cables and heating pipes.

In order to get an anhydrite-based concrete of a certain quality, there must be a certain ratio between water and anhydrite quantity. This is called the water-anhydrite ratio. It indicates the number of liters (kg) of water for each kg of anhydrite, and has the designation v/a. If you want, for example, a waterproof concrete, you must proceed from v/a = max. 0.5, i.e. a maximum of 0.5 1 water for each kg of anhydrite, including the water in the aggregate.

In our research and development, gabbrolite stone materials have shown outstanding properties as aggregates for concrete.

The diagram, which is from a test, shows the importance of the amount of water for the firmness of an anhydrite-based concrete with baukulan and with aggregates as indicated in the table below. The curing time was 29 days.

The test shows that a number of new and surprising results can be achieved by changing the parameters.

In particular, two versions of anhydrite-based concrete have been tested, namely 1. Baukulan concrete, composed of baukulan base with sand and stone aggregates, and 2. Baukulan industrial concrete, composed of baukulan base with aggregates of gabbrolite.

Both versions are laid like normal concrete and can have a laying height from 0.8 cm to unlimited.

Edition 1, baukula concrete, is very suitable for pouring from 0.8 - 5 cm, as scratch-free floors with very good adhesion are achieved. It is suitable as a casting for heating cables.

Edition 2, baukulan industrial concrete, provides a very strong surface with great wear resistance against heavy loads. It is therefore suitable for heavy industry, car parks, roads and bridges.

Anhydrite-based concrete has the following general properties:

Gives virtually no waste in the material.

Withstands temperatures up to 1450°C, i.e. it withstands

e.g. glowing aluminum.

Environmentally friendly, emits no harmful gases.

Very dense and stable mass.

Provides extremely high compressive strength 35-80 N/mm<2>, and bending strength 8-14 N/mm<2>.

Provides a very flat surface.

Can be laid on extremely difficult surfaces.

Gives even colors when dyed without lime penetration. Can be pumped with a simple mechanical pump and with large car pumps without the addition of quality-deteriorating additives.

In general, the same methods are used for cement-based and anhydrite-based concrete when it comes to production, transport of concrete to the construction site, pumping of concrete, casting methods. summer casting, winter casting and surface treatment.

Claims (2)

1. Casting compound, comprising sand, stone and any additives and materials, CHARACTERIZED BY the fact that it contains anhydrite as the only binding and hardening agent which, when water is added, causes the casting compound to harden and become hard. 2. Molding compound according to claim 1, CHARACTERIZED IN THAT the binding and hardening agent is synthetic anhydrite.