Foam concrete
As foamed concrete or lightweight porous concrete ( PLB ) is a heat-insulating lightweight concrete Denoted by using foam or air-entraining agents is prepared.
Foam concrete is more of a mortar as a concrete in the usual sense, since concrete 4 mm larger than a maximum particle size as defined , while foam concrete in general, no aggregates containing mm about. 2 On the other hand, in contrast to mortar, foam concrete can be processed into solid components, as the pore content prevents the material from tearing when it hardens.
Aerated concrete has comparable properties to which only rock flour is added and which is hardened by means of saturated water vapor. This is used in the form of blocks as masonry , as it cannot be produced as in-situ concrete .
Very light foam concretes are also known as cement-based foam or mineralized foam .
Foam concrete is not standardized concrete; DIN standard 4164: 1951-10 existed for certain areas, but was finally withdrawn in April 2006.
In contrast, air- entrained concrete is a standardized type of concrete with a maximum macropore content of 5%, which is often used to manufacture frost-resistant components, for example in road construction .
properties
Foam concrete can be pumped, has a soft or flowable consistency and does not require compression after installation. However, as the density decreases, it has an increasingly high degree of creep and shrinkage. The bulk density of foam concrete is in the range from 400 kg / m 3 to 2000 kg / m 3 . Corresponding strengths of approximately 1 N / mm 2 to 25 N / mm 2 are achieved. The proportion of pores is usually over 30%. If aggregate is added, it has in most cases a maximum diameter of 2 mm.
Manufacturing
Unlike the pre-made bricks and components made of cellular concrete foam concrete is produced on site or as a ready-mix concrete delivered fresh from the concrete plant. Lightweight aerated concrete can be produced up to a density of 1.4 kg / dm 3 with the addition of a foaming agent directly in the compulsory mixer ( mixing process ). Alternatively, as well as for the production of concrete up to a density of 0.4 kg / dm³, the foam is first produced with the help of a special foam device and then mixed with the fresh concrete ( foam process ).
use
Foam concrete is used in Europe, for example, to fill cavities or for lightweight, heat-insulating leveling layers.
Web links
literature
Individual evidence
- ↑ a b c Concrete technical data: 12.14 Foam concrete - lightweight porous concrete. HeidelbergCement AG, accessed on September 2, 2018.