DE3709374A1 - Porous lightweight concrete - Google Patents

Abstract

The invention relates to a porous lightweight concrete for producing floors, slabs and similar mouldings with defined components of mineral fillers such as sand, inorganic binders such as cement and lime, aluminium powder as blowing agent and water. In this arrangement, in order to make possible an adaptation of the properties of the gas concrete to, inter alia, particular climatic conditions and to achieve the simplest possible production, it is proposed by the invention that the raw material which is mixed so as to be pourable now contains the following components: a) the initially dry-mixed filler and binder with the addition of water and finally blowing agent or b) mineral filler ground with water to form slurry with subsequent mixing with binder and further water and finally blowing agent. Thus, with a minimum number of conventional components used, a porous concrete is produced whose bulk density is 400-600 kg/m<3> and whose physical properties, in particular as regards thermal insulation and compressive strength, meet the requirements in the construction industry. Some preferred formulations are also proposed by the invention.

Description

Pore lightweight concrete for the production of blocks, slabs and the same structural parts with defined proportions of filling substances, binders and blowing agents.

Gas concrete has become because of its light weight easy to process and not least because of its good heat and sound insulation properties always more than universally applicable building material prevailed.

Sand is mainly used for its production defined grain size, also finely ground with binders such as lime and / or cement mixed with the addition of water and mixed with a blowing agent. As further additives can sand and waste sludge, as well as organic and inorganic masses of different particle shapes be used.

The particular physical properties of the End product depend essentially on the properties of the components used, their mixing ratio and from time course of the individual manufacturing phases. Because the essential ingredients from natural raw materials exist, the manufacturing process must depend on the consistent properties of the used Components are aligned to the location. For the production of gas concrete, the components are made according to a certain recipe weighed in its proportions and because of beginning chemical reactions in certain mixed time-dependent phases, the addition of Aluminum powder as a blowing agent usually at the end of the Mixing phase takes place.

The finished mixture is immediately poured into molds where the Driving process takes place. The Al particles loosen in the strongly alkaline viscous mass with formation of Hydrogen on. The H2 bubbles that form drive it Mass up and provide along with the binding of water the other components for their solidification. The use is to achieve special stability usual steel reinforcements possible. After a certain dwell time it will be sufficient stable mass taken from the mold, machine into the intended shape cut and at about 180 degrees C in Autoclave hardened with the addition of water vapor.

The advantageous properties of gas concrete such as high Compressive strength with low weight, good heat and Sound insulation and favorable diffusion behavior are therefore by the recipe used and by the time Manufacturing process adjustable within limits.  

So is an adjustment of the properties of gas concrete to special climatic conditions possible. Especially when the outside temperature is high, it becomes more southern Countries and with low construction lighter gas concrete with high proportion of closed pores preferred.

It comes down to that, taking into account that frequently unsuitable infrastructure of such countries as simple as possible Manufacturing methods using the country's raw material apply fabrics.

This object is achieved by the formulations according to the invention in that, with a minimum number of conventional components used, a cellular concrete is produced, the bulk density of which is 400-600 kg / m ³ and whose physical properties, in particular with regard to thermal insulation and pressure resistance, correspond to the requirements in construction. The following recipes / m ^{3 of} pourable raw material have proven to be suitable for producing the lightweight porous concrete according to the invention:

• 1. 290 kg sand 66 kg of lime 113 kg of cement 230 kg of water 0.42 kg aluminum powder
• 2,294 kg of sand 110 kg of lime 65 kg of cement 230 kg of water 0.42 kg aluminum powder
• 3,246 kg of sand 62 kg of lime 68 kg of cement 314 kg of water 0.5 kg aluminum powder
• 4,238 kg of sand 64 kg of lime 70 kg cement 310 kg of water 0.41 kg aluminum powder
• 5. 718 kg of sludge 40 kg of water 75 kg cement 30 kg of lime 3.5 kg aluminum powder
• 6.590 kg of sludge 100 kg of water 111 kg of cement 40 kg of lime 3.5 kg aluminum powder
• 7. 890 kg of sludge 70 kg of water 90 kg cement 80 kg of lime 2.5 kg aluminum powder
• 8. 930 kg of sludge 100 kg of water 90 kg cement 90 kg of lime 2.2 kg aluminum powder

An example of the production of the invention Pore lightweight concrete is shown in the picture. It shows

1-4 silos for sand, lime, cement and blowing agents

4 a Cold / warm water supply

5 weigh

6 mix

7 pour

8 bustle

9 u. 10 cutting

11 hardships

12 water vapor

13 sand mill.

To produce the lightweight porous concrete according to the invention, individual components of sand, cement, lime and water are removed from their silos 1-4 a according to recipe 1-4 , weighed in 5 and mixed in 6.

After the final addition of aluminum powder, the pourable raw material is poured into molds 7 with the onset of the blowing process, after the mass 8 has hardened into the moldings 9 and 10 provided. 10 cut and cured in the autoclave 11 with previous evacuation and subsequent introduction of water vapor 12 .

In a modified production process according to recipe 5-8 , the sand ground in the sand mill 13 is first mixed with water to form a sludge and only then, as described above, mixed with the other components. This results in a faster and more homogeneous mixture of the finished raw material with a greatly reduced amount of dust. Another advantage of reducing the risk of explosion and better mixing results when using aluminum paste instead of aluminum powder.

Sand can also be used unground. Usually will, however, for better control of the curing process and the properties of the end product by screening specified maximum grain size allowed.

Waste can be added as a further filler in both modifications sludge can be used.

After removal from the autoclave, the molded parts can be in Used or another surface Processing or remuneration can be supplied.

Claims (13)

1. lightweight porous concrete for the production of blocks, plates and the like moldings with defined constituents of mineral fillers such as sand, inorganic binders such as cement and lime, aluminum powder as blowing agent and water, characterized in that its pourable mixed raw material

• a) the initially dry mixed fillers and binders with the addition of water and finally blowing agent or
• b) mineral filler milled with water to form sludge, followed by mixing with binders, further water and finally blowing agent.

2. Pore lightweight concrete according to claim 1a), characterized in that the pourable raw mass / m ³ consists of 290 kg sand, 667 kg lime, 113 kg cement, 230 kg water and 0.42 kg aluminum powder. 3. lightweight porous concrete according to claim 1a), characterized in that the pourable raw mass / m ³ consists of 294 kg sand, 110 kg lime, 65 kg cement, 230 kg water and 0.42 kg aluminum powder. 4. lightweight porous concrete according to claim 1a), characterized in that the pourable raw material / m ³ consists of 246 kg sand, 62 kg lime, 68 kg cement, 314 kg water and 0.5 kg aluminum powder. 5. lightweight porous concrete according to claim 1a), characterized in that the pourable raw mass / m ³ consists of 238 kg sand, 64 kg lime, 70 kg cement, 310 kg water and 0.41 kg aluminum powder. 6. lightweight porous concrete according to claim 1b), characterized in that the pourable raw mass / m ³ consists of 718 kg of sludge, 30 kg of lime, 75 kg of cement, 40 kg of water and 3.5 kg of aluminum powder. 7. lightweight porous concrete according to claim 1b), characterized in that the pourable raw material / m ³ consists of 590 kg of sludge, 40 kg of lime, 111 kg of cement, 100 kg of water and 3.5 kg of aluminum powder. 8. lightweight porous concrete according to claim 1b), characterized in that the pourable raw mass / m ³ consists of 890 kg of sludge, 80 kg of lime, 90 kg of cement, 70 kg of water and 2.5 kg of aluminum powder. 9. lightweight porous concrete according to claim 1b), characterized in that the pourable raw mass / m ³ consists of 930 kg of sludge, 90 kg of lime, 90 kg of cement, 100 kg of water and 2.2 kg of aluminum powder. 10. lightweight porous concrete according to claims 1-9, characterized in that its bulk density is in the range of 400 to 650 kg / m ³ . 11. lightweight porous concrete according to claims 1-10, characterized characterized in that instead of aluminum powder Aluminum paste is used. 12. lightweight porous concrete according to claim 1-5, characterized characterized in that the filler is unground, however sieved sand of defined maximum grain size is used becomes. 13. lightweight porous concrete according to claim 1-12, characterized characterized in that waste sludge as a further filler is used.