the Additives accelerating shvatyvanie difficult and cement mortals, apply, if the solution has to be made bystroshvatyvajushchimsja, and also for durability increase in early terms tverdenija. They are necessary and by manufacture of works during winter time.
Accelerators are chloride calcium, chloride sodium, hydrochloric acid, ground not slaked izvest, carbonic kaly - potash. These are usually soluble powders in water.
It is necessary to know that chloride additives give vysoly on a plaster surface. And still: it is impossible to apply them on internal works owing to danger of a poisoning of people.
the Best accelerator is potash.
The Quantity of accelerating additives is defined by building laboratory or make trial zamesy.
a Fig. 2. Cement-gun .
1 - the electric motor; 2 - the bunker; 3 - the handle for transportation; 4 - a hose;
Special additives are demanded by the waterproofing solutions applied when it is necessary to provide water resistance of a plaster covering.
Such additives are tserezit and liquid glass .
Tserezit enter into cement mortal structure, and liquid glass is both a superficial covering, and the additive in solutions.
Tserezit - smetanoobraznaja weight, in water is not dissolved, and forms emulsiju. For preparation of a solution 1 part tserezita stir in 10 parts of water and on this emulsii shut a structure cement mortal 1:3.
The Layer tserezntovoj plasters in 2 sm is sufficient in the thickness for maintenance of a waterproofing of crude cellars and superficial tanks. It is better to put it a cement-gun (fig. 2).
At the big pressures of water tserezitovaja plaster water resistance does not guarantee.
To shvatyvanija a solution the surface needs to be protected from water that there was no washing away tserezita, in hot weather to cover a damp bast mat.
Liquid glass - dense siropoobraznaja weight, it consists from kremnekislyh shchelochen.
Before the use the weight should be checked up areometrom - the device defining a fortress of solutions, then to dissolve with soft rain water. Concentration of the dissolved liquid glass define in laboratory.
Liquid glass put on well dried out plaster in 3... 4 layers, giving to each layer it is good to dry out.
If prepare a solution with the additive of liquid glass a mix of cement with sand shut a solution of liquid glass in the ratio 1:5... 1:10 (liquid glass: water). Solutions on liquid glass quickly seize, it is necessary to prepare them in the small portions.
Solutions on liquid glass give water-proof kislotostojkuju plaster. They do not protect only from influence of fluoric connections and phosphoric acid.
For water-proof plasters as the additive can serve and sodium aluminate, this substance it is hazardous to health of the person, razdrazhajushche operates on a skin, mucous membranes. Therefore use it extremely seldom and it is necessary to observe variety of obligatory and very strict requirements of safety precautions. To the dresser without reception of special instructing, without supervision of the master to start to work with sodium aluminate it is impossible.
To receive acoustic (sound-proof) plaster, there are some recipes of solutions at which, as a rule, there is a pumice or slag with the same density as at pumice, - 400 kg/m 3 . Such are solutions ATSP (acoustic cement-pumiceous), AGP (acoustic gipsopemzovyj), ATSSH (acoustic cement-slag), ASP (acoustic soljanopemzovyj on magnesite). All these solutions lungs with density 600... 1200 kg/m 3 .
For an example I will tell, how prepare only one solution - ATSP. Droblenuju pumice is sifted through two sieves with apertures in the size by of 5 and 3 mm. As a filler the rest which was formed on a sieve with apertures of 3 mm serves. Cement and pumice mix dry in the ratio 1:4 on volume and shut in 1 volume of water. Use here portlandtsement marks 400.
Plaster can serve and protection against x-ray radiations, for example for isolation of x-ray offices from other adjacent premises. For this purpose in a cement or difficult heavy solution in density of 2200 kg/m 3 add baritovyj sand, baritovuju a dust. Prepare them, as usual solutions.
I Will repeat once again that it is necessary to take all components of solutions in strictly certain parity. For selection of components on buildings use the ready tables made on the basis of long-term experience, scientific workings out.