43. Plastering solutions with antifreeze additives

Solutions on chlorinated water . In unheated rooms, in rooms with partial heating, as well as in the cold, plastering works are carried out with solutions with chemical additives.

For exterior plastering work, chlorinated solutions (solutions mixed with chlorinated water) are used. Such solutions can plaster surfaces at temperatures up to -25 ° C without subsequent heating of the plaster.

To prepare chlorinated water, water is poured into the boiler, heated to + 35 ° С, then bleach is put into it (12-15 hours of bleach per 100 l of water). The solution is stirred until complete dissolution of lime. The chlorinated milk obtained is placed for 1-1.5 h to settle, after which the sludge of chlorinated water is drained into the supply tank and used to prepare the solution. Chlorinated water should not be heated above + 35 ° C, since chlorine will evaporate and water will lose activity. It is strictly forbidden to use non-settled chlorinated water, since cracks appear in the sludge or turbidity when it enters the plaster.

Chlorinated water can be used to prepare complex or cement mortars that plaster wooden, brick or concrete surfaces. Other types of solutions should not be prepared with chlorinated water.

The following compositions of chlorinated solutions are recommended - cement: lime paste: sand (1: 1: 6) or cement: a mixture of clay and ground slag: sand (1: 1.5: 6). These mortar formulations are used for plastering brick, cinder block and wood surfaces. Concrete surfaces plastered with cement mortar composition from 1: 2.5 to 1: 3.

The temperature of chlorinated water for the preparation of solutions should not be below + 10 ° C, the temperature of the materials depends on the outdoor temperature. The lower the air temperature, the higher should be the temperature of the solutions, and in windy weather is higher than in quiet.

The temperature of the plaster, regardless of the outdoor temperature, should be at the time of application and grouting not lower than + 5 ° C.

Chlorinated solutions are applied manually or mechanized ways. Each subsequent layer of the solution should fall on the previously thickened layer. After setting, the grouting is done.

Poorly dried ordinary plasters applied in winter are covered with ice, which reduces their strength. The strength of the chlorinated plaster increases in the cold.

Chlorinated solutions can be painted with alkali-resistant and light-resistant mineral paints (earth), for example, mummy, ocher, iron red lead.

Workers preparing chlorinated water or mortar and using chlorinated mortar directly on plastering work must be trained in safety instructions. To work with these solutions, they are required to wear canvas overalls, rubberized apron and mittens; need to wear rubber boots. Work with chlorinated solutions can only be in a gas mask or respirator.

Plastering with chlorinated solutions inside the premises is not allowed. As an exception, it is allowed to plaster niches under the radiator, provided that the windows are open.

Chlorinated plasters are harmless after drying, since chlorinated solutions completely set on the eighth day, and during this time the chlorine from them evaporates.

Solutions with the addition of potash . Solutions with the addition of potash do not give efflorescence, do not cause corrosion destruction of the metal, so they can also be used when plastering mesh-reinforced structures.

Aqueous solution of potash is prepared cement-clay, cement-lime and cement mortars. Color solutions are prepared using alkali-resistant pigments.

For the preparation of the solution using Portland cement of low marks. The amount of potash taken depending on the outdoor temperature. So, for example, at an ambient air temperature of up to -5 ° C, 1% of the mass of the dry mixture is taken; when the outside air temperature is from -5 to -15 ° C, 1.5%; .

Potash is added to the dry plaster mix as an aqueous solution.

Cement-clay solutions are used in the following compositions: from 1: 0.2: 4 to 1: 0.5: 6 (cement: clay: sand). To prepare the solution, the dried clay is mixed with cement and then closed with an aqueous solution of potash. Clay can be pre-turned into a dough, and then mixed with cement and sand.

Cement-lime mortars should contain no more than 20% lime by weight of cement. Prepare them in the usual way.

Cement solutions should be non-greasy, composition 1: 3. Salt of potash is dissolved in water, on which a solution is prepared from a cement-sand mixture or this water is added to thick solutions.

It is recommended to use preheated solutions up to +5? 10 ° C. The solution should be used within an hour from the moment of its preparation. The solution is stored in insulated container.

Before plastering, surfaces are cleared of snow, ice and dirt. Stamps and lighthouses suit from the solution, which plaster the surface. When plastering under reduced temperature, the spray is not applied to the surface, but a creamy solution is prepared and immediately applied to the substrate in layers with a thickness of 10-12 mm. The soil is leveled, scratched and a coat of 7-8 mm thick is applied over its thickened layer. Smooth out and rub over without moistening with water.

The worker preparing the solution with the addition of potash, should be dressed the same way as working with chlorinated solutions.

Solutions on ammonia water . Solutions prepared in ammonia water do not give efflorescence.

Ammonia water is obtained from the plant, it is diluted at the workplaces in the mortar nodes to the required concentration. The temperature of ammonia and ordinary water for its dilution should not exceed 4-5 ° C, since at a higher temperature ammonia evaporates. If ammonia water has a 25% concentration, then to obtain ammonia water of 6% concentration, 3.16 l (rounded 3 l) of ordinary water is added to each liter of it. If ammonia water of 15% concentration is delivered, then 1.5 l of water is added per liter of it. Ammonia water delivered from the factory or diluted in the workplace is stored in a hermetically sealed container, preferably in glass bottles with ground stoppers.

Ammonia water shut cement and cement-lime mortars with sand; lime, lime-gypsum and cement-clay solutions should not be shut off with ammonia water.

When grouting on concrete, it is recommended to use a cement mortar of composition 1: 2-1: 4 (cement: sand); for plastering brick, slag concrete and wood surfaces - cement-lime-sand mortar compositions 1: 1: 6-1: 1: 9 (cement: lime paste: sand).

Lime paste is diluted with ammonia water, the temperature of which should not be below + 5 ° C. The heating temperature of the solution depends on the outdoor temperature. If the outside air temperature is up to - 15 ° С, then the temperature of the solution at workplaces should be +2? 3 ° С. When the ambient temperature is up to -25 ° С, the temperature of the solution should not be lower than + 5 ° С. Plastering with ammonia water is acceptable at air temperatures down to -30 ° C.

To obtain solutions of this temperature, the materials included in them are heated. After mixing, the temperature of the lime test and ammonia water should be no higher than + 5 ° C. Solutions must be supplied to workplaces in insulated boxes closed with soft rubber gasket covers, which prevents ammonia from volatilizing and retains heat.

The plaster on ammonia water after freezing has high strength, the surface film does not peel.

This plaster continues to gain strength in the cold and in the heat after the solution thaws. The procedure for plastering is the same as when plastering solutions with other antifreeze additives.

When mechanized application of the solution is recommended to use a pressure-free nozzle.

On ammonia water can be prepared and colored solutions using alkali-resistant pigments.