How to make refractory concrete by yourself?

Construction of facilities for different purposesquite often requires the use of refractory materials. With their help you can protect people and designs. Refractory concrete acts as one of such materials. Some of its varieties are able to undergo the influence of temperature up to 1000 ° C, while the shape and useful properties are preserved.

Basic properties

Among the main features of such concretes are:

• high refractoriness;
• increased operational properties;
• strength;
• no need to use an expensive firing process in production.

Today, refractory concrete can be classified by weight. You can make or order the following varieties of the described material:

• especially heavy;
• light;
• cellular;
• heavy.

As a result, it is possible to obtain a material that can perform a structural or thermal insulation function, depending on the ingredient composition.

Production features

If you decide to make refractory concrete, then you should become more familiar with its composition. The material is made on the basis of basic components and some additives, among which are:

• chamotte sand;
• magnesite;
• different types of rubble;
• aluminous cement.

Among additives it is necessary to allocate still finely ground and mineral substances which give to a material durability. Among such additives:

• pumice;
• finely ground chromite ore;
• blast furnace slag.

These components are added to improvedensity of not only the finished product, but also dry composition. Sometimes fillers for production are manufactured in the factory, but in some cases refractory rocks and baked fire brick can be used. To obtain different grades of concrete, fillers of different fractions are added. If it is a coarse-grained substance, its elements can have a diameter in the range of 5 to 25 mm. When it comes to the fine fraction, it is equal to the limit of 0.15 and 5 mm. Among these ingredients should be allocated:

• magnesite brick;
• fireclay bricks;
• bout ordinary brick;
• aluminous slag;
• diabase;
• basalt;
• blast furnace slag.

The most common among consumersis refractory concrete, which is made using chamotte, because it meets all the requirements of construction. Aluminum phosphate ingredients and liquid glass act as a linking agent. Portland cement, periclase and alumina cements and serve as binding agents. If the liquid glass is added to the ingredients, it allows to increase the performance characteristics. This is especially true if the concrete solution is used to form the plaster layer.

Additional technology recommendations

Refractory concrete, the composition of which is described inarticle, can have a certain brand. Each variety assumes the addition of its plasticizer, magnesite powders and ferrochrome slags. If there is an objective to prepare lightweight concrete, then the expanded materials should be of the following type:

• vermiculite;
• expanded clay;
• perlite.

If you decide to order a mixtureprofessional, then the ratio of components they pick up themselves, in accordance with your project. The composition is selected for the operating temperature and service conditions.

In addition to the composition of the filler type

If you decide to make refractory concrete with your own hands, then you can use different fillers, namely:

• dinas;
• corundum;
• quartz;
• finished mixtures.

Considering concretes by composition, it is necessary to allocatebrand. For example, ASBG is a refractory dry alum containing mixture that is used in non-ferrous and ferrous metallurgy, as well as in heat power engineering. High-alumina concrete mixture with refractory characteristics is designated by the abbreviation VGBS and is intended for creation of monolithic lining of steel ladles, walls and at the bottom.

The use of such a composition maytemperature up to 1800 ° C. The reinforcement dry high-alumina mixture is designated by the letters SSBA. It is intended for thermal aggregates, furnaces, as well as reinforcing layer devices. The operating temperature can reach 750 ° C.

Drying of concrete

Drying of refractory concrete can be carried outafter completion of the solidification step. This uses air, and the ambient temperature should not be below +10 ° C. Prior to initial heating, concrete should be kept for a day or more in order to achieve a steady state. The drying operation allows to reduce the amount of free water in the concrete, which could cause a chemical reaction between the atmosphere and the surface of the lining.

After curing, the lining is left onmoist air without drying. After curing is complete, dry the lining. If this is not possible, the concrete is left in a closed, moist environment. It is important to ensure good ventilation or leave the lining in a well-ventilated area. If you have wondered how to make refractory concrete, then you should be familiar with the specifics of its preparation for operation. For example, the drying step may take place using a suitable fan or blower that will supply hot air.

Features of mixing

Before making refractory concrete itshands, the composition of the solution must be carefully selected. This was mentioned above. As for the peculiarities of mixing, it is recommended to use a paddle mixer for this. It is preferable for thermal insulating concretes, but for dense solutions it is absolutely necessary, since it allows to mix the material evenly and correctly with the addition of a smaller volume of water. As for the concrete mixer, this effect will be very difficult to achieve.

This recommendation is also relevant for thethe reason that for dense concrete the moisture content can be critical. After all, for the described materials, the maximum strength is required along with the optimal density. By its nature, thermal insulating concretes are softer than dense, so it is important that they are kneaded using the required amount of water. Its surplus can cause a decrease in strength and density, while a drawback will entail a decrease in fluidity.

Proportions of refractory concrete

The preparation of refractory concrete must be carried outwith certain proportions. If a fireplace is to be built using the material, the solution should be able to withstand a temperature of 1200 ° C after solidification. From the mixture it is possible to make a fireplace and firebox. To carry out the work, one part of M-400 concrete, two parts of sand made of refractory bricks, as many pieces of crumb from a bricks battle, as well as 0.33 parts of a pulverized chamotte additive will be required.

If you are planning to build a monolithic hearth,the open flame will always be affected by it during the operation of the heating equipment. To do this, you need to prepare a solution with the following proportions: 2.5 parts of rubble, part of concrete, 0.33 parts of chamotte sand. As for the rubble, it can be made of quartz or red brick, as an alternative solution, sometimes a thin red brick is used.

Conclusion

Features of solution preparation for creationRefractory concrete are similar to those used in the process of shutting down a conventional cement slurry. If it is intended to fill in the formwork, the movement should be clockwise. Sometimes forms of plywood are used to form the products.

In order to avoid evaporation of water inthe process of solidification, the form after manufacturing should be sealed. This facilitates easier extraction of castings. The simplest method of sealing is polyethylene, but in order to achieve the best result, you should use silicone, which is pre-lubricated with vegetable fat.