Analysis of the advantages of foam concrete (foamed concrete)

1. Advantages of foam concrete compared with organic insulation materials

Organic insulation materials refer to those foam plastics represented by polystyrene foam and polyurethane foam that have been widely used in construction. Compared with these materials, foam concrete has great advantages in building insulation. These advantages determine that it is necessary and appropriate to replace organic insulation materials with foam concrete.

1.1 Fire prevention advantages

Whether it is foamed polystyrene or other organic insulation materials such as foamed polyurethane, they are flammable and have strong flashover properties. The fire is fierce and difficult to put out. Even flame-retardant organic foam materials still cannot avoid fire. In some of the recent major fires in our country, flame-retardant foam plastics were used in the projects. At the same time, the burning smoke of foam plastics is very toxic and can spread up to several kilometers. The national key projects Jinan Olympic Sports Center and the new CCTV building have experienced fire scenes caused by organic insulation materials.

Foam concrete is made of cement as the main material, which is a safe and non-combustible material. Its fire resistance level is greater than 2 hours, reaching Class A fire protection standards, and can fully meet the fire protection requirements of any building. Using foam concrete for building insulation will not cause fire at all.

What’s more advantageous is that the cast-in-place foam concrete cast-in-place insulation wall we developed can completely cover the steel structure in foam concrete and protect the steel structure. Even if a fire occurs, the steel structure It is also not easy to deform and collapse, which solves the fire protection problem of steel structures and provides double fire protection.

1.2 Durability Advantages

The design life of a building is generally 50 to 100 years. Organic insulation materials have a problem of not being able to withstand aging and cannot last as long as the building. At present, the design life of organic insulation materials in relevant specifications for building insulation is mostly 20 to 25 years. This means that the insulation layer and the building cannot have the same lifespan. A building needs to be insulated at least 2 to 4 times. This repeated tossing of the building shortens the service life of the building. Because every construction will cause damage to the building.

Foam concrete has a durability of more than 50 years and can last as long as the building. One-time insulation construction can keep the building insulated for life, avoiding the shortcomings of multiple insulation constructions. The foam concrete roof insulation layer in Heilongjiang and other places in my country was constructed under the guidance of experts from the former Soviet Union in the early 1950s. It has been intact for nearly 60 years and is still in use. This has fully demonstrated the durability of foam concrete. Under the premise of standardized construction, the service life of high-quality foam concrete can reach 100 years, and it is also suitable for key construction projects.

In addition, due to poor integration of organic exterior wall insulation with the wall, engineering accidents such as cracking and falling off are often caused, which not only makes the durability of the project impossible to guarantee, but also poses a serious threat to people due to falling objects. of. The organic insulation layer is peeling off both at home and abroad.

Most of the foam concrete is self-insulated by the wall, so there is no problem of the outer insulation layer falling off. A small number of external walls are insulated, most of them are anchored or dry-hanging, which is not easy to fall off, and a few are pasted. Since foam concrete and the wall are made of the same material, the bond is very strong and not easy to fall off.

1.3 Sound insulation advantages

Organic insulation materials such as polystyrene foam boards have poor sound insulation. For a foamed polystyrene wall with a 50mm thick core layer, the voices on both sides of the wall can be clearly heard, while for a foam concrete wall with a 50mm thick core layer, the voices on both sides of the wall are basically inaudible. The foamed polystyrene sandwich wall makes a loud banging sound and feels hollow when struck, but the foam concrete sandwich wall does not make that much noise and does not feel hollow when struck.

When the closed cell ratio of foam concrete is greater than 90%, it becomes an excellent sound insulation material. Some developed countries in the West use foam concrete to produce sound insulation panels.

1.4 Advantages of non-toxic and harmless

Organic insulation materials such as polystyrene foam and polyurethane foam release a large amount of harmful gases during production. The smell at the production site is choking and seriously pollutes the air. , harmful to the health of operators. In the early stages of use, there is still a residual smell. In the later stages of use, its aging and decomposition will still release harmful substances. Therefore, its production and use are not environmentally friendly. This does not take into account the white pollution it easily causes.

Foam concrete is basically made of inorganic materials. No harmful substances are produced during production, and there is no odor at the production site. It will not produce decomposition products during use and is green and environmentally friendly. From the perspective of building greening, it should also be the best choice for building insulation.

1.5 Advantages of not consuming large amounts of petroleum resources

In addition to reducing emissions, building energy conservation also has the significance of reducing my country's energy consumption and protecting national energy security. Organic insulation materials such as foamed polystyrene mostly use petroleum as the starting material, consuming a large amount of petroleum resources. Their application will aggravate my country's energy crisis. Although its use can save energy in buildings, the raw materials consume energy, making energy saving and energy consumption conflict, and the meaning of energy saving is lost.��

The raw material of foam concrete is cement, not energy. Although the production of cement also consumes energy, it is lower than the total energy consumption of raw materials and production of foamed polystyrene.

2. Advantages of foam concrete compared with other inorganic insulation materials

Inorganic insulation materials that can replace organic insulation materials are mainly foam concrete, aerated concrete, foam glass, and mineral wool rock Cotton, vitrified beads, ceramsite, etc. These inorganic materials will occupy a certain proportion in the future building insulation market, realizing the complementary advantages of various inorganic materials, but foam concrete has more advantages. With its advantages, foam concrete will stand out among these inorganic insulation materials. Occupy the dominant position of building insulation.

2.1 Advantages of foam concrete compared with aerated concrete

Comparing aerated concrete with foam concrete, its obvious advantages are that it has higher strength than foam concrete and uses less cement. The cement content of aerated concrete is only 5% to 10%, while foam concrete is mostly 100% cement, at least 50% cement. However, the comprehensive advantages of foam concrete are far greater than those of air-entrained concrete, allowing it to still occupy a larger market share in future market competition. There are five biggest advantages of foam concrete:

2.1.1 Advantages of cast-in-situ construction

Aerated concrete cannot be constructed on-site because it requires autoclaving. One car can bring the entire set of foam concrete equipment to the site, and seven people can pour 100 to 200m3 on site in one day. Cast-in-place roof insulation layer, cast-in-place floor heating insulation layer, cast-in-place self-insulating wall, cast-in-place exterior wall insulation wall, cast-in-place floor cushion, and cast-in-place core column are all the strengths of foam concrete, and It will play an important role in building insulation in the future. It is no exaggeration to say that the largest application of building insulation in the future may be cast-in-situ foam concrete.

Although the material cost of foam concrete is high, because it can be cast on site, it saves a lot of production energy consumption and product processing costs, and its density is low, and the total amount of raw materials used for production is small. This reduces the total cost and resolves its disadvantages, and the cost is lower than that of aerated concrete. Self-insulating walls can thin the wall and reduce the amount of insulation materials. The cost of the cast-in-place foam concrete wall is even lower, which obviously shows the advantages of cast-in-place insulation.

2.1.2 Advantages of low water absorption

The water absorption rate of air-entrained concrete is as high as more than 45%, which has always been its major disadvantage. This disadvantage makes it difficult to paint, requiring the use of interface agents. Even if interface agents are used, engineering accidents such as hollowing, peeling, and cracking of the stucco layer often occur.

Foam concrete can freely control the water absorption rate by adjusting its closed cell ratio. Its general water absorption rate is about 20% to 25%, and low water absorption products are about 8% to 12%. Ultra-low water absorption Rate products can reach 2% to 5%. This advantage of low water absorption not only avoids the above-mentioned disadvantages of aerated concrete, but also fills the gap that aerated concrete cannot be used in alpine areas. At present, we have produced and applied ceramsite foam concrete blocks in Heilongjiang. Insulation is most needed in these places, and air-entrained concrete cannot be used due to high water absorption. I think that in areas such as Northeast China, Inner Mongolia, Qinghai, Xinjiang, and Tibet where aerated concrete cannot be used so far, foam concrete will make a big difference. Figure 6 shows the condition of water droplets on the surface of foam concrete ultra-low water absorption products.

2.1.3 Advantages of low density and ultra-light weight

The density of air-entrained concrete is mostly 500~800kg/m3. There are very few products with a density lower than 500 kg/m3 and cannot be produced stably. There are almost no products above 300 kg/m3. Due to the constraints of process technology, it is difficult to produce ultra-light products below 400 kg/m3 from aerated concrete. The current building energy conservation requires ultra-light products below 400 kg/m3, because their thermal insulation performance is better and it is more conducive to lightweight buildings.

At present, the widely used foam concrete has a density of generally 200-450 kg/m3, which just makes up for the shortcomings in the performance of aerated concrete. The two form market complementarities and dislocations. Figure 7 shows the ultra-light display of foam concrete.

The thermal conductivity of the leading aerated concrete products B05~B07 is 0.14~0.18w/m·k, while the thermal conductivity of the leading foam concrete products B02~B04 is only 0.065~0.10 w/m· k, which is only half that of air-entrained concrete. This means that by using foam concrete to meet building energy-saving standards, the wall can be nearly twice as thin as that of air-entrained concrete, which can save a lot of material and increase the usable area.

In summary, the following conclusion can be drawn: As the same type of insulation materials, aerated concrete and foam concrete have their own advantages, but foam concrete has more advantages. In the density grade range of B06 to B07, air-entrained concrete will have an advantage due to its good strength. In the range of cast-in-place and density levels below B05, foam concrete will have an advantage. The two can achieve complementary advantages in the market. From the perspective of total application volume, foam concrete will definitely exceed aerated concrete in 3 to 5 years.

</p