How to make fireproof (heat -resistant, heat -resistant) concrete with your own hands – composition

One of the most adaptable and popular building materials in the world is concrete. Though its strength and durability are well known, did you know that it can also be made to withstand heat? For building outdoor ovens, fireplaces, and even some areas of your house that must endure high temperatures, fireproof concrete is a must. It’s not as hard as it might seem to make heat-resistant concrete at home, and with the right supplies and a little know-how, you can accomplish expert results.

The composition of the concrete is the key to making it fireproof. Ordinary concrete is composed of cement, sand, and gravel; however, this mixture needs to be altered in order to endure high temperatures. Crushed firebrick, fireclay, and refractory cement are a few examples of materials that can greatly increase the heat resistance of your concrete. These ingredients are specifically made to withstand extreme heat without degrading, and you can find them at most building supply stores.

It’s critical to use the proper proportions when mixing heat-resistant concrete. One part cement, three parts sand, and two parts crushed firebrick are often combined in a recipe, along with just enough water to make it workable. Adding fireclay to the mixture enhances the overall durability and thermal stability of the concrete, which is another benefit. Ensuring that the fireproof properties of the concrete are uniformly distributed requires a thorough mixing of these ingredients.

Your fireproof concrete is ready to be used in your construction project once you’ve mixed it. This heat-resistant concrete will offer the required durability and safety whether you’re building an outdoor oven, a fireplace, or a barrier to keep out heat. You can confidently take on your fireproof concrete projects and benefit from a material that withstands heat with the correct supplies and careful preparation.

Component	Description
Cement	The primary binder that holds the concrete together. Use high-alumina cement for better heat resistance.
Aggregate	Use crushed fire bricks or heat-resistant stones to provide structure and volume.
Sand	Fine particles that fill gaps and add strength. Opt for fire-resistant sand if possible.
Water	Activates the cement and helps the mixture to bind. Use the minimal amount needed to create a workable mixture.
Fireclay	Adds additional heat resistance. Mix with the cement to improve the overall durability of the concrete.

General information: materials and characteristics of heat-resistant concrete

Refractory concrete, on the other hand, can tolerate short-term heating and temperatures up to +200C. Heat-resistant concrete is a unique kind of concrete material that can withstand temperatures in the range of +1580-1770C for a long time without losing its mechanical and operational properties.

Both residential and commercial buildings are built using concrete. Chimneys, fireplaces, saunas, baths, and barbecues are all made with refractory and heat-resistant concrete.

Heat-resistant concretes start to dry out, fracture, and deteriorate after reaching their maximum temperature and after a certain amount of time.

• High strength
• Reliable thermal insulation
• Enhanced operational characteristics during operation
• Ease of preparation (additional firing is not needed)
• Reduction in time, money, and labor costs

Concrete that is resistant to heat can also be structurally sound and insulating. The structure is dense, cellular, and light-permeable.

Composition of dense fire-resistant mortars

Dense, heavy, heat-resistant concrete (with varying compositions) is typically used to build fire-resistant structures and as a heat-resistant lining in specific thermal units, such as blast furnace recuperators in the chemical industry, special brick kilns, and chimney pipe construction.

Use of heavy mixtures can result in substantial cost and labor savings, as well as a significant reduction in the time required for thermal unit construction and repair.

Knitting

The production of heat-resistant concrete follows GOST 20910 90. This paper raises the possibility of preparing the solution with different binders.

• Liquid glass
• Aluminous (here you can also include high-alumina) cement
• Slag Portland cement with special microfillers
• Portland cement with mandatory inclusion of microfiller (finely ground additive)

A combination of Portland cement and slag Portland cement is typically used in neutral or alkaline environments. Liquid glass is appropriate for an environment that is gas acidic. Opting for aluminous and high-alumina cements is preferable in environments with high levels of carbon, phosphorus, and hydrogen.

To strengthen the composition and enhance the structure, mineral components such as t.d., chamotis/magnesite brick, a les-shaped loam, andesitis, and domain slag in granules, can be added.

Fillers

In order for refractory concretes to withstand fire and high temperatures, the proper fillers must be added in addition to special binders. The fillers must expand uniformly. Regular fillers provide resistance up to +200C, after which they start to lose durability and distort completely at +600C.

When preparing refractory concrete, it is assumed that fillers will be used that won’t collapse or soften at high temperatures and won’t put undue stress on the monolith’s internal structure.

• +600 – 800C: rocks (diabase, andesite, basalt), porous materials from volcanic rocks, these can be blast furnace granulated slags, broken bricks, artificial porous structures (expanded perlite, expanded clay, slag pumice is suitable, etc.d.).
• +1200 – 1700C: crushed refractory materials are added – chromite, fireclay brick, magnesite, often chosen corundum, burnt kaolin.
• It is possible to add special materials obtained by firing a mixture of refractory clay and magnesite at high temperatures – aluminosilicates, which are characterized by minimal deformation, good fire resistance.

Technical requirements

The following requirements must be met by the fire-resistant concrete grade:

• Concrete type: heat-resistant is designated by the letters BR
• Binder: aluminate (A), portland cement (P), silicates (S)
• Compressive/tensile strength class – B1-B40
• Operating temperature – IZ-I18

For instance, BR P B20 I12 will be the designation for heat-resistant concrete made of portland cement with a strength of B20 and the ability to withstand +1200C.

When it comes to density, materials with an indicator of 1100 kg/m3 are utilized as thermal insulation for enclosing non-load-bearing structures, and materials with an indicator of 1400 kg/m3 are used for enclosing load-bearing structures of public and residential buildings. There are eighteen classes of concretes based on the maximum temperature: Only non-load-bearing structures use I13–I18.

Concrete with a density of 1500 kg/m3 is expected to have water resistance between W and W8. The level of frost resistance is F-F75. The kind of binders used and the precise heating temperature have a direct impact on residual strength and temperature deformation index under mechanical load.

Regarding the strength class, stressed heat-resistant structures should have an index of at least B30; in the absence of a load, at least B12 is acceptable.5.

You might be surprised to learn how easy it is to make fireproof concrete at home. Heat-resistant mixtures can be made by mixing ingredients like silica sand, Portland cement, perlite, and a tiny bit of water. Because of its unique ability to tolerate high temperatures, this concrete is perfect for outdoor ovens, wood stoves, and fireplaces. You can create a strong, heat-resistant material that can withstand the heat and keep your projects safe with just a few simple ingredients and some basic mixing.

Main types of heavy fire-resistant concrete

Refractory concrete can have a variety of compositions depending on the necessary properties, the materials used, and their ratios. The primary kinds of heavy concrete are covered in the sections that follow.

Concrete on Portland cement and slag Portland cement

This is the most popular kind of heat-resistant concrete; it has good strength, is inexpensive, and uses tried-and-true preparation and application techniques. This kind of concrete is typically used to build heating systems, chimneys, nuclear power plant structures that are fireproof, etc.

The strength class should fall between B15 and B40. In the preparation process, only active mineral substances (fuel ash, chamotte, blast furnace slag, etc.) are added to cement that is M400 or higher. Adding finely ground chamotte additives to the mixture yields the longest-lasting concrete.

The technology for metallurgical blast furnace slag addition in slag Portland cement allows the mixture to be used for mixing concrete that is expected to be exposed to temperatures no higher than +700C.

On aluminous aluminate cement

Concretes with a heat resistance class between I8 and I18 are made from these materials. Calcium dialuminate, or high-alumina cement, is the primary mineral ingredient in this type of cement. The concrete can withstand temperatures as high as +1300C if no additional additives are added. However, if a filler consisting of corundum and aluminum oxide is added, the temperature can rise to as high as +1650C.

• Minimal thermal shrinkage, small linear expansion during heating
• High mechanical strength
• Maintaining a stable state with sudden temperature changes
• Minimal thermal conductivity
• The structures can be used within 24 hours after pouring

Liquid glass as a binder for heat-resistant concrete

Prior to creating heat-resistant concrete from liquid glass, it is essential to thoroughly examine the mixture’s composition. The use of potassium/sodium compositions enables the use of refractory concretes at temperatures between +800 and 1600C.

Liquid glass has three possible moduli: high (represented by the letter B), medium (represented by the letter B), and low (represented by the letter A).

• The best indicators of sodium glass as a binder for a refractory mixture are with a silicate module of 2.0-3.5, potassium – 2.5-4.0.
• Liquid glass hardens for a long time, so various hardeners are added to the mixture (sodium fluorosilicate compound, alkali metal fluorosilicate). In addition to rapid hardening, these substances help to increase the strength and density of the solution. Also, to accelerate hardening, you can add ferrochrome, ferromanganese slag, nepheline sludge.
• It is worth noting that various plasticizers, finely ground additives, regulators, additives for better workability can be introduced into the composition of the mixtures.
• For a cubic meter of concrete, you need about 250-400 kg / m3 of binder, hardener – 0.1-0.2 parts of the weight of the binder. You will need about 0.12-0.3 of the weight of liquid glass.
• The solution based on liquid glass is mixed on site, since the mixture must be poured within half an hour. Laying is carried out at a temperature of at least +15C, humidity should be maximum 70%.

Other types of fire-resistant concrete

The same binders are used in the production of lightweight cellular/porous concrete, but weight-reducing foaming agents or porous fillers are added.

Lightweight porous concrete

Here, a variety of porous materials, such as expanded clay, expanded perlite, and volcanic tuff, that can withstand temperatures of up to +1000C, are used as fillers. Grades D300–1800 correspond to lightweight concretes.

Grouping porous concretes according to their intended use:

• Structural – with a density of 1400-1800 kg / m3, minimum strength M50, any thermal conductivity.
• Heat-insulating – with a density of maximum 500 kg / m3, strength in the range of M14-M25, thermal conductivity maximum 0.14 W / m * K.
• Heat-insulating and structural – strength at least M35, thermal conductivity within 0.14–0.54 W/m*K, density is 500-800.

High levels of fire resistance are shown by lightweight concretes made with Portland cement or aluminous cement. F25-100 is the increased frost resistance achieved when crushed stone with expanded clay is used as a filler.

Cellular concrete

This kind of solution is utilized as a heat-resistant material and for thermal insulation. When building privately, cellular concrete is frequently used in the form of blocks or prefabricated buildings from factories.

• For thermal insulation – density up to 500 kg / m3
• Heat-insulating and structural – the indicator is in the range of 500-900 kg / m3
• Structural – from 1000 to 1400
• Heat-resistant – up to 1200 kg / m3, can be used at temperatures up to + 800C

This kind of concrete won’t change structurally after being exposed to an open fire for five to seven hours. The material’s strength increases to + 400C when heated, and it completely breaks down at + 1000C.

The fire resistance limit of the cellular material can be raised when making heat-resistant concrete by hand by adding alkaline aluminosilicate binders, metallurgical slags, fuel ash, and lime-belite compositions.

Application

Refractory and heat-resistant concrete are typically used in the building of metallurgical, chemical, and energy structures. The material can be used to build heating plants, blast furnaces, and smelters.

In daily life, heat-resistant concrete preparation is required when building furnaces, heating boilers, and fireplaces. Additionally, heating circuits are laid out and pipe terminals are made from the solution. Concrete for private construction is manually mixed using specific ingredients, closely adhering to guidelines, and measuring exact amounts.

After at least three days (quick-hardening cement, aluminous, liquid glass), seven days (Portland cement), or once the monolith has achieved the design strength, new structures are put into service. The structures are dried to eliminate all free water from the composition before heating. heated in compliance with specific modes and technological guidelines.

Home production

Purchasing a pre-made mixture and mixing the material as directed by the instructions (which are typically found on the container’s back) is the simplest method of creating heat-resistant concrete by hand. It’s very easy to do: pour the dry mixture into a concrete mixer, mix for a minute, and then stir in regular water or glass liquid.

• Choosing the optimal composition of materials.
• Pouring 90% of the required volume of water or liquid glass (in diluted form) into a concrete mixer.
• Filling with finely ground additive, adding half of the filler and cement, mixing, gradually adding the remaining materials, the rest of the water (or glass).
• Mixing should be carried out for at least 5 minutes.
• Shipment of the ready-made mixture directly at the site, pouring.

The process of creating fireproof concrete at home is simple and provides a lot of safety and versatility for a range of projects. The proper materials can be carefully chosen and combined to create a mixture that is heat-resistant and long-lasting, making it ideal for high-temperature settings.

The main ingredients of fireproof concrete are aggregates, cement, and additives such as silica fume or fireclay. Together, these components strengthen the concrete’s ability to withstand heat and keep it from deteriorating or cracking in hot weather. Accurate measurement and thorough mixing are necessary to guarantee a reliable and efficient finished product.

Correct curing is essential once you’ve got the right mixture. In order to keep the concrete from drying out too quickly, let it set gradually and evenly while maintaining moisture. In order to maximize the strength and fire resistance of your homemade concrete, this step is essential.

You can confidently make fireproof concrete that satisfies your unique needs by following these steps. For any heat-exposed structure, such as an outdoor oven or fireplace, your homemade mix will offer dependable performance and safety.

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