Inorganic insulation materials that can replace organic insulation materials are mainly foam concrete, aerated concrete, foam glass, mineral wool, vitrified microspheres, 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.
1 Advantages of foam concrete compared with aerated concrete
Compared with foam concrete, the obvious advantage of aerated concrete is 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:
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.
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 a major disadvantage of it. 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.
1.3 Advantages of low density and ultra-light
The density of air-entrained concrete is mostly 500~800kg/m3. There are very few products with a density below 500 kg/m3 and cannot be produced stably. The density is below 300 There are almost no products in 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.
1.4 Advantages of flexible process and wide variety
Due to limitations of autoclaving process and equipment, aerated concrete is basically mainly made of blocks and strips, and other types There are no products yet, which has reduced its application scope and market share to a certain extent.
Foam concrete can be used for various cast-in-place constructions and can also be produced using different processes. Currently, there are more than 10 types of foam concrete insulation products, and there will be dozens in the future. Foam concrete responds quickly to market demand and has strong adaptability. When the market demands a certain product, it can be produced quickly, or even a new product can be produced by changing a mold. This cannot be done with air-entrained concrete. For example, foam concrete can produce large-sized sandwich roofs and wall insulation panels. The current maximum size has reached 3000×6000mm, which cannot be achieved with air-entrained concrete. For another example, foam concrete can easily produce lightweight core-filled products and sandwich products. , air-entrained concrete cannot; another example, foamFoamed concrete can easily produce ceramsite reinforced products, colored products, special-shaped products, etc. Air-entrained concrete cannot. This determines that foam concrete will occupy more application areas with its production flexibility.
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.
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