The production of Lightweight concrete can be divided into two types according to the different foaming methods: physical foaming and chemical foaming.
It has the following advantages:
1. Lightweight, the density of foam concrete is small, and the density grade is generally 300-1800kg / m3, the density grade of commonly used foam concrete is 300-1200 kg / m3, in recent years, the ultra-light foam concrete with a density of 160 kg / m3 is also It has been applied in construction engineering;
2. Excellent thermal insulation performance, because the foam concrete contains a large number of small closed pores, so it has excellent thermal performance, that is, excellent thermal insulation performance, which is not available in ordinary concrete. Generally, the foam concrete with a density grade of 300-1200 kg / m3 has a thermal conductivity of 0.08-0.3w / (m · K) and thermal resistance of about 10-20 times that of ordinary concrete;
3. Excellent sound insulation and fire resistance;
4. The overall performance is excellent, can be cast on-site construction, tightly integrated with the main project;
5. Low elasticity and excellent shock absorption;
6. Strong waterproof performance;
7. Excellent durability and the same life as the main project;
8. Convenient production and processing;
9. Good environmental performance;
10. Easy construction.
The physical method of foaming is to use chemical foaming agents to pressurize the foam to form a foam with a certain tension, and then mix the foam and the cement slurry at the same time. During the mixing process, the cement will continue to expand. When the expansion effect reaches the preset ratio, The foamed cement can be formed.
The steps of using physical foaming to make lightweight concrete:
1. Add cement, coal ash, concrete additives, and other materials to the water and mix well;
2. Use foam generator to foam the diluted foaming agent, and directly add the produced foam to the stirred cement slurry;
3. Add foam in accordance with the designed ratio to continuously expand the cement slurry to reach the designed volume.
Physical foaming application areas: roof insulation and cast-in-place construction, ground leveling and backfilling, bathroom backfilling, production of lightweight partition walls, cast-in-place walls, various special-shaped components, decorative lines, outdoor molding.