Refractory concrete is a specific kind of concrete that can tolerate very high temperatures. It is also referred to as heat-resistant concrete. In settings and industries where traditional concrete would fail from heat damage, this material is indispensable. Among other high-temperature applications, it is frequently utilized in the construction of furnaces, kilns, incinerators, and fireplaces.
Refractory concrete’s composition gives it special qualities. It contains ingredients like alumina, calcium aluminate cement, and occasionally silicon carbide, unlike ordinary concrete. Refractory concrete is able to withstand temperatures as high as 1500°C (2732°F) or higher, depending on the formulation, because of these ingredients.
Refractory concrete not only resists heat well but also provides good thermal insulation, helping to keep interior temperatures constant while safeguarding the environment. Additionally, it is made to withstand thermal shock, which is the strain brought on by abrupt temperature changes. Because of this, it is exceptionally long-lasting and durable in settings with frequent extreme temperature swings.
Knowing the technical properties of refractory concrete is essential when working with it. These consist of its thermal conductivity, density, and compressive strength. To ensure the best performance and safety, choose the appropriate type of refractory concrete for a given application, as these attributes can differ greatly depending on the specific mixture used.
All things considered, refractory concrete is an essential component of industrial and high-temperature construction processes. Its remarkable thermal performance, along with its resilience and insulating qualities, make it an indispensable option for projects requiring extreme heat tolerance.
Feature | Description |
Heat Resistance | Can withstand very high temperatures without breaking down or losing strength |
Durability | Maintains its structural integrity over time, even under extreme conditions |
Insulating Properties | Offers good thermal insulation, reducing heat transfer |
Applications | Used in furnaces, kilns, and other high-temperature environments |
Composition | Made from a mixture of cement, aggregates, and special additives to enhance heat resistance |
Installation | Can be cast or applied in various forms, including bricks and panels |
Maintenance | Requires minimal maintenance due to its robust nature |
Curing Time | Needs proper curing to achieve full strength and heat resistance |
- The composition of refractory concrete
- Binding substances
- Militators
- The main characteristics of the material
- Classification of concrete
- The scope of application
- Preparation technology
- Composition and proportions
- Features of kneading
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The composition of refractory concrete
Depending on its intended use, the material’s precise composition may change. For instance, the composition of solutions for chemical industry businesses may differ from heat-resistant mixtures used in chimney construction.
Crucial! In accordance with GOST 20910-90, heat-resistant concrete is made with an astringent, filler, and specific additives.
Binding substances
The most popular astringent that doesn’t significantly raise the cost of the mixture, Portland cement is most frequently used to produce fire-resistant concrete, which is characterized by strength, dependability, and a long history of well-developed technology.
For the installation of heat units and chimneys, fireproof concrete that is based on cement from the M400 brand and higher is appropriate. Its strength class is B15–B40, and the composition must include the active mineral component (chamotopic clay, domestic slag) and the fine-grained filler (fine-ground additive).
Additional types of binding materials for concrete that withstands heat:
- Slag -portland cement. In addition to Portland cement, it includes a small amount of domain slag. Used for the preparation of concrete, which withstand the maximum temperature up to +700 degrees.
- Liquid glass (sodium or potassium compounds). Ready -made refractory concrete with such binding can be operated at temperatures within +800 … +1600 degrees, as well as in a heated gas medium. In structure, liquid glass is highly modular, medium -ground, low -muddy. It is cured for a long time, therefore, accelerators of the reaction are additionally introduced into the concrete solution: sodium siliconfluoride, alkaline metals, ferrochrome, ferromarganese, nephelin sludge.
- Clay -earth or high -grain cement. It is used as an astringent if heat -resistant concrete will be operated in a hydrogen, carbon, phosphorus medium at temperatures up to +1300 degrees. The main mineral component of this type of concrete should be a mon- or calcium dialyumate. With additional introduction of corundum, aluminum oxide, thermal resistance of concrete will increase to +1650 degrees. Designs based on clay -earth cement are characterized by minimal shrinkage, low linear expansion when heated, high strength, and stability at temperature differences. For even greater hardening of their structure, Andesitis, chamotopic crumbs, domain slag is additionally introduced into the composition.
Concrete’s heat resistance can be increased by substituting silicate or phosphate compositions for some of the astringent. The final solution will harden and gain strength more quickly, and it will be easier to grasp with the base. It is also more appropriate for usage in an acidic environment.
Militators
Fillers are crucial in helping concrete be resistant to high temperatures during the manufacturing process.
Crucial! They need to be carefully chosen so that they can withstand the effects of fire and expand uniformly in both high and low temperatures. Conventional fillers are destroyed at +600 degrees and can only withstand heating to a maximum of +200 degrees.
Only specific aggregates—which do not soften in the presence of high temperatures and do not induce excessive voltage in the monolith—are appropriate for a heat-resistant solution. These could be:
- Basalt, Andesit, Diabase (withstand up to +600 … +800 degrees);
- Brick battle, expanded clay, perlite, slag pumice, blasting slag in granules (do not deteriorate at temperatures up to +1200 … +1700 degrees).
You can use aluminosilicates, chromite, chromagnesitis, burned kaolin, corundure, and chamotis brick as fillers.
The main characteristics of the material
When purchasing a finished mixture, the most crucial factor that needs to be understood is its heat resistance. It can be +700… +1800 degrees and higher depending on the precise composition; heating shouldn’t result in the loss of mechanical and functional properties. Even heat-resistant concrete will start to dry out, crack, and collapse once it reaches its maximum temperature.
Additional technical details of the substance:
- Compression and stretching strength – from B15 to B40;
- density – up to 1100 kg/m³ (the solution is used for thermal insulation of structures without high load), up to 1,400 kg/m³ (the composition is suitable for the fencing and supporting structures of residential buildings), about 1,500 kg/m³ (concrete is suitable for any structures);
- The level of maximum heating temperatures is from M13 to I18;
- water resistance – to W8;
- Frost resistance – to F75.
Classification of concrete
Groups of heat-resistant concrete can be distinguished based on their level of resistance to heating. These groups include:
- Heat -guided. Transfer temperatures up to +700 degrees and do not deteriorate from short -term heating to +1500 degrees. Typically, they include Portland cement, slag portland cement.
- Refractory. Designed for structures that serve at temperatures up to +1000 degrees. Maintain short -term heating to +1800 degrees. Liquid glass, clay -earth substances are introduced into the composition.
- Highly exumer. Can be used at temperatures up to +1800 or more. Among the components there are a chip of chamotis brick, diatomic battle, etc.D.
Concrete is categorized based on their structural makeup:
- Light porous (brands D300-D1800). Fillers in such materials: porous raw materials such as perlite, expanded clay, volcanic tuf. Foaming agents that reduce the mass of monoliths can also be introduced into the composition.
- Cellular. Usually used as heat -resistant thermal insulation. Implemented in the form of blocks or finished designs.
- Dense. Are a type of heavy concrete with increased heat resistance.
The material can serve as heat-insulating and structural (strength-minimum M35), thermal insulation (strength within M14–M25), or structural (strength of M50).
It is important to read the labeling on mixtures when purchasing them to determine which components to buy:
- VGBS – high content of clay substances;
- SBB-B-concrete with chamotis battle;
- Sabt-Butane-Propan Technical mixture;
- SBK – composition with corundum;
- SSBA – reinforcing fire mixture;
- ABC – aluminosilicate concrete.
Refractory concrete, sometimes referred to as heat-resistant concrete, is perfect for use in high-heat settings like furnaces, kilns, and fireplaces because it is specially made to withstand extreme temperatures and harsh conditions. Certain components, such as binders and refractory aggregates, are added to this kind of concrete to improve its durability and heat stability. Its resistance to thermal shocks and capacity to maintain structural integrity at high temperatures are among its important characteristics, though its exact formulation frequently affects these attributes. In order to choose the best kind of refractory concrete for your project and ensure longevity and safety, it is essential to understand these features.
The scope of application
The utilization of heat-resistant concrete is highly common in the building of commercial and residential structures.
Its primary applications are:
- designs in thermal energy, metallurgy, recuperators of domain furnaces, individual elements of furnaces for firing bricks, chimneys;
- internal surfaces of buckets for pouring combustible materials;
- lining of furnaces, other thermal units;
- structures in the chemical industry;
- Mangals, saunas, baths, fireplaces;
- pipe conclusions, heating contours;
- Reinforcement of concrete slabs.
Preparation technology
It is crucial that the structure’s operational humidity remain constant even at elevated temperatures when producing materials with heat-resistant qualities. This effect will be aided by the addition of unique additives and finely dispersed fillers, which will stop the object from overheating and thermally destroying it.
Crucial! The chosen binding and filler, which have already undergone stiff heat treatment and do not undergo morphological or chemical changes, must be ready in advance.
When producing these kinds of materials, the following production cycle will be followed:
- selection of composition;
- measurement of components;
- kneading;
- layout;
- Drying of the product.
The only distinction is that using a lobed mesh to better knead the thin-dispersed fractions is worthwhile. The standard concrete mixer is utilized in its absence. It will also be helpful to have a car for carrying tools and components, as well as containers for measuring the parts.
Composition and proportions
If you’d like, you can make refractory concrete with a ready-made mixture that already has all the ingredients. Any building supply store will have the necessary materials; just look for the label bearing the appropriate abbreviation.
Heat-resistant supplements are added in finely chopped form after autonomous kneading. They are crushed to a gravel fraction or powder state, depending on the goal of the solution.
Traditional method for combining the solution:
- 3 parts of heat -resistant filler;
- 2 parts of the sand;
- 2 parts of cement;
- 0.5 parts of bastard lime (to enhance the viscosity of the mixture).
Crucial! About 7.5 liters of water are used for every 22 kg of dry mixture. The fluid’s volume may change based on the user’s requirements.
Features of kneading
Lime is added to improve the additives after the cement base and fillers have been thoroughly mixed. Water is poured in small amounts. The mixture is worked into a uniform, flat mass that resembles a test. In her hand, she shouldn’t blur or crumble.
After pouring, the completed structure is dried in a damp but ventilated room. It is necessary to cover the formwork with a lid or film to stop moisture from evaporating unevenly. Avoid allowing the product to heat up or the flame’s effect; instead, mist the surface with water on a regular basis.
Refractory concrete is a special kind of material that is used in many different industrial applications because of its ability to withstand extremely high temperatures. Its special composition, which consists of binders and heat-resistant aggregates, enables it to keep its structural integrity even in extremely hot conditions. This makes it indispensable in situations where regular concrete would fail, like furnaces, kilns, and incinerators.
The durability of refractory concrete is one of its main advantages. Refractory concrete is stronger and more stable than regular concrete, which can break down and deteriorate in high temperatures. This durability lowers maintenance costs and improves the security of buildings that are subjected to intense heat.
Refractory concrete is renowned for its insulating qualities in addition to its resistance to heat. It efficiently reduces heat transfer, preventing thermal damage to nearby materials and structures. This makes it a great option for applications in residential and commercial buildings where fire resistance is essential, in addition to industrial settings.
Refractory concrete excels over conventional concrete in high-temperature settings due to its technical qualities, which include its compressive strength, thermal conductivity, and resistance to thermal shock. Engineers can customize refractory concrete to meet specific performance requirements by carefully choosing the right mix of materials, guaranteeing the best results for any given application.
Refractory concrete is an essential material in manufacturing and construction where heat resistance is critical. Because of its strength, resilience, and thermal insulation, it is a vital tool for maintaining the security and longevity of high-temperature installations. The durability required to endure intense heat is provided by refractory concrete, which can be used in both specialized construction projects and industrial environments.