Gypsum concrete partitions: material and construction

How does the installation of gypsum concrete partitions from finished panels look like? How and according to what standardizing documents are these panels produced? How to finish gypsum concrete partition? Let's figure it out.

Gypsum concrete: first acquaintance

What is gypsum concrete?

This is the name for concrete, in which gypsum is used as a binder instead of traditional cement.

In addition to (and often instead of) sand, various mineral and organic fillers are used:

• Slag is one of the wastes of metallurgical production.
• Ash obtained by burning coal and wood.
• Peat.
• Straw is a by-product of agriculture.
• Textile rags (simply put, unnecessary rags).
• Wastepaper.

The presence of organic fillers reduces the tensile and compressive strength of the material, but makes it more elastic (in particular, allows you to drive a partition into nails made from gypsum concrete), improves thermal insulation qualities and resistance to impacts.

However: the most common composition includes, in addition to gypsum, sand and sawdust. It combines sufficient compressive strength with excellent thermal insulation properties and manufacturability.

The density of gypsum concrete is from 1100 to 1500 kg / m3.

What are the consumer properties of this material?

Virtues

• Low weight, allowing to build partitions on a wooden floor.
• Heat and sound insulation properties already mentioned by us.
• Ease of processing. If during the splitting of the main walls it may be necessary not only a chisel and a hammer, but also cutting of reinforced concrete - concrete with diamond circles, reinforcement - with an ordinary abrasive - then here you can even make strobite with a chisel and light hammer. Diamond drilling of holes in concrete also cannot be compared with its laboriousness with drilling gypsum concrete: it is taken by an ordinary metal drill.

disadvantages

There are not so many of them.

• The ease of machining a material is the downside of its limited mechanical strength. Actually, that is why gypsum concrete is not used for the construction of capital walls: its scope of application is limited to unloaded partitions.
• The moisture resistance of the material is low and due to the corresponding properties of gypsum. From here - a practical conclusion: gypsum concrete is not suitable for partitions in bathrooms and bathrooms. In any case, it should not be used for the construction of walls in direct contact with water.

Production

Internal partitions of the material discussed by us can be erected in two ways:

1. Pouring in formwork. This method, however, is practiced very rarely.
2. Assembled from finished panels.

According to what regulatory documents and how are gypsum concrete panels manufactured for partitions?

Standard

Production и нормируемые качества продукции регулируются принятым на излете советской эпохи ГОСТ 9574-90.

Curiously: in the header the document is positioned as the state standard of the Union of the USSR; however, it was adopted in January 1992, when the Soviet Union collapsed.

Let's explore the key points of the standard.

• The regulatory document applies to all panels produced on the basis of a gypsum binder for the needs of construction. In particular, its text mentions gypsum-slag, gypsum-limestone-slag and gypsum cementopozzolan panels.

• Products without openings are marked with letters PG. Panels with openings are indicated by the GWP index, with cutouts - PGW.

• The presence of gates, grooves and boxes for wiring and sockets is determined solely by the conditions of construction and is not strictly regulated.
• Full product labeling contains the following sections:

• Panel type (PG, PGP or PGV).
• Its overall dimensions are: length and height in decimeters rounded to the nearest whole number, as well as thickness in centimeters.
• Hyphen separating groups of symbols.
• Brand of concrete (its compressive strength).
• A full description of the binder (G - gypsum, GSH - gypsum slag, GI - gypsum limestone, HZ - gypsum cement puztsolanovoy).

Thus, the product with marking ПГ60.27.8-50Г is a panel without openings and cutouts with dimensions of 6x2.7x0.08 meters based on a gypsum binder, having a compressive strength of 50 kgf / cm2.

Please note: 50 kgf / cm2 is the minimum value of compressive strength allowed for gypsum concrete.

• The density of the dry panels is already known to us - from 1100 to 1500 kg / m3. The permissible humidity range is up to 12% for gypsum binders and up to 14% for other binders.
• Wood is used to reinforce the panels. Paired bars tie the contour of the panel itself and openings or cuts in it; slats link contour frame.
• For the manufacture of reinforcement is strongly recommended to use coniferous wood up to the 3rd grade inclusive. Peeled bark wane is allowed (it should be facing the inside of the panel) and splicing one of the paired framework bars; at the same time the number of splices on each side of the panel should not exceed two.

The use of hardwood is also allowed (except for birch: with high hardness, its wood is too susceptible to rotting) everywhere, except for the lower strapping bars. Wood moisture should be in the range of 22 to 40 percent.

• The panels are equipped with steel mounting hinges, which are sealed to the full height of the product. The location of the loops is coordinated for a specific project in the working drawings.

By the way: in agreement with the customer, the panels can be produced without loops. In this case, they require the use of special grippers to move.

• The panel material must be free from cracks (except for surface ones, not more than half a millimeter wide). No more than 2 holes per square meter of surface are allowed with their diameter or the largest size up to 20 mm.
• Panels are stored and transported in a vertical position.
• As already mentioned, gypsum gets along poorly with high humidity; however, panels made on the basis of the HZ binder (gypsum-cemento-pizzolan) material can still be used in wet rooms.

In addition to the above, the standard regulates the maximum permissible deviations from the specified dimensions and control methods.

Technology

What is the production of gypsum concrete panels?

We have already mentioned above that in housing construction we will receive the most widespread material consisting of gypsum, sand and sawdust. The proportions of the components are 1: 1: 1.

Manufacturing method - continuous forming on a rolling mill.

1. The components are metered into the mixing hopper, where they turn into a homogeneous dry mass.
2. Next, water and a set retarder for gypsum (animal glue) are mixed in with it.
3. Pre-rolled frames are stacked on the rolling mill belt. The gypsum-concrete mass is fed directly to them through a slot dispenser and is evenly distributed by sizing rollers with continuous vibration. The rolls form a layer of the required thickness.
4. The formed and set panel enters the drying chamber, where during the day it contacts with air or flue gases at a temperature of 130 degrees.
5. After drying, the finished product enters the warehouse.

The thickness of gypsum concrete partitions is usually 80 or 100 millimeters; interroom walls are built double, with an air gap of 50 millimeters thick.

Installation

How to build a plasterboard with your own hands? It is clear that in this case it is necessary to use panels of small dimensions: products with an area of ​​several square meters are mounted only at the construction stage, before laying the floor slabs and assembling the roof.

The instruction looks like this:

1. The base is leveled with a cement pad if necessary.
2. Concrete is waterproofed from the future partition with two layers of roofing material. (See also the article Aerated concrete partitions: features.)
3. At the edges of the partition, ordering is set (vertical slats with labels corresponding to the rows of panels) and the mooring is stretched - a horizontal cord.
4. The first row of panels is installed dry.
5. Preparing a portion of the binder for the seams - gypsum with a retarder setting.

Useful: ready-made plaster plaster or its mixture with alabaster can be used for filling joints. In the second case, the price of a kilogram of solution will be somewhat lower; however, it will take some time to experiment on the selection of the optimal ratio, which will give the necessary setting time.

1. Vertical seams are filled with a binder and bolted with reinforcement.
2. At the level of the upper horizontal slot in the wall, a pair of holes are drilled into which the reinforcement segments are driven in. A long section (or several segments) of reinforcement that fits into the groove is knitted to them with a wire.

1. On top of the groove laid out a plaster solution. The next row of panels is installed on it along the mooring raised to the appropriate level. Of course, with the obligatory ligation of vertical seams: from row to row, they are displaced by at least a quarter of the length.

The following rows are laid out in a similar way. The space between the upper cut of the partition and the ceiling is filled with tow with gypsum solution applied on it. For cutting gypsum concrete, the easiest way is to use a grinder with an ordinary cutting wheel over a stone; circular saw and jigsaw, too, take it, but quickly become blunt.

Finish

How to finish the finished partition?

The accuracy of the geometric dimensions of the panels allows you to do without plastering the surface, and the porous structure will provide excellent adhesion of inexpensive gypsum fillers. (See also become Facing aerated concrete: how to do.)

Putting the entire surface is not that necessary - it is desirable: it will completely hide the seams and make the partition perfectly flat, which will be useful for painting or glossy smooth wallpaper.

1. The partition is ground by hand grater or sanding mesh..
2. The surface is dedusted with a vacuum cleaner or whisk and primed with penetrating acrylic primer..
3. Универсальная или финишная гипсовая шпаклевка наносится в два-три максимально тонких («на сдир») слоя с промежуточной просушкой.

1. Surface re-ground and primed..

Conclusion

We will consider our acquaintance with the new material held. As usual, the video in this article will offer the reader additional information on the topic we are discussing. Successes in repair!

And how to cut reinforced concrete with diamond circles, as well as diamond drilling holes in concrete, see the video in other articles on this site.