Inorganic thermal insulation materials that can replace organic thermal insulation materials are mainly foam concrete aerated concrete, foam glass, mineral wool rock wool, vitrified microbeads, ceramsite, etc. These inorganic materials will occupy a certain proportion in the future building insulation market and realize the complementary advantages of various inorganic materials. However, foam concrete has more advantages. With its advantages, foam concrete will stand out among these inorganic insulation materials, occupying the main position of building insulation.
Advantages of foam concrete compared with aerated concrete
Compared with foamed concrete, aerated concrete has the obvious advantage of higher strength than foamed concrete and less cement consumption. The amount of cement in aerated concrete is only 5%-10%, while most of the foamed concrete is 100% cement, and at least 50% or more cement is required.
However, the comprehensive advantages of foamed concrete are far greater than that of aerated concrete, so that it will still occupy a larger market share in the future market competition. five biggest advantages of foam concrete:
1. The advantages of cast-in-place construction
Aerated concrete cannot be constructed on site due to autoclave. Foamed concrete can be pulled to the site by a single car, and seven people can cast 100-200m3 in a day. Cast-in-place roof insulation layer, cast-in-place floor heating insulation layer, cast-in-place various self-insulation walls, cast-in-place exterior wall insulation wall, cast-in-place floor cushion, cast-in-place core column, are all the strengths of foam concrete, and will show their talents in the future of building insulation. It is no exaggeration to say that the largest application of building insulation in the future may be cast-in-place foam concrete.
Although the material cost of foamed concrete is high, because it can be cast-in-place, it saves a lot of production energy consumption and product processing costs, and has low density and a small total amount of raw materials for production. It reduces the total cost and resolves its disadvantages, but the cost is lower than that of aerated concrete. With the self-insulating wall thinning the wall and reducing the amount of insulation material, the cost of the cast-in-place foam concrete wall is even lower, which obviously shows the advantages of pouring insulation.
2. The advantage of low water absorption
The water absorption rate of aerated concrete is as high as 45%, which has always been a major disadvantage of it. This disadvantage makes it difficult to paint, requiring the use of interface agents. Even when the upper interface agent is used, engineering accidents such as hollowing, peeling, and cracking of the whitewashed layer often occur.
Foamed concrete can freely control the water absorption rate by adjusting its closed cell rate. The general water absorption rate is about 20% to 25%, the low water absorption rate product is about 8% to 12%, and the ultra-low water absorption rate product can reach 2%~5%. This advantage of low water absorption not only avoids the above-mentioned disadvantages of aerated concrete, but also fills in the gap that aerated concrete cannot be used in alpine regions. At present, we have produced and applied ceramsite foam concrete blocks in Heilongjiang. In these places, thermal insulation is most needed, and aerated concrete cannot be used due to its high water absorption. I think that foam concrete will do a lot in areas where aerated concrete cannot be used until now, such as Northeast China, Inner Mongolia, Qinghai, Xinjiang, and Tibet. Figure 6 shows the condition of water droplets on the surface of foam concrete ultra-low water absorption products.
3. Low-density and ultra-light weight
The density of air-entrained concrete is mostly 500～800kg/m3. There are few products below 500 kg/m3 and cannot be produced stably. There are almost no products below 300 kg/m3. Due to technological constraints, aerated concrete is difficult to produce ultra-light products below 400 kg/m3. At present, energy-saving buildings require ultra-light products below 400 kg/m3, because their thermal insulation performance is better, which is more conducive to building lighter construction.
At present, the density of widely used foam concrete is generally 200-450 kg/m3, which just makes up for the lack of performance of aerated concrete, and the two form a complementary and misplaced market. Figure 7 shows the ultra-light display of foamed concrete.
The thermal conductivity of the leading aerated concrete product B05～B07 is 0.14～0.18w/m·k, while the thermal conductivity of the leading foam concrete product B02～B04 is only 0.065～0.10 w/m·k, which is only equivalent to aerated concrete. Half of the concrete. This means that using foamed concrete to meet building energy-saving standards, the wall can be nearly twice as thin as aerated concrete, which can save a lot of materials and increase the use area.
In summary, the following conclusions can be drawn: aerated concrete and foam concrete have their own advantages as the same type of insulation material, but foam concrete has more advantages. In the density range of B06～B07, aerated concrete will have an advantage due to its good strength. In the cast-in-place and density range below B05, foam concrete will have an advantage. The two can realize the complementary advantages of the market. From the perspective of total application, foam concrete will definitely surpass aerated concrete after 3 to 5 years.
