Wall saltpetres are often shown on surface of ceramic brick, there is it because this material is cellular. Drying, products pass through themselves water solution of salt from cement. As soon as moisture evaporates from the basis, on surface there is salt.
If you have garage, private or brick country house, then, for certain, you had to notice that red facing can grow white. It always attracts question of the nature of emergence of such formations which are called wall saltpetres.
What is wall saltpetres
White stains on surface of brick are result of crystallization of salts. This process is preceded by salt solution migration in time of products which absorbs moisture from solution. The moisture coming to brick body is saturated with salt. During drying of product, water with salt begins to move on capillaries, coming to surface, after it evaporates, leaving crystals of salts which find type of wall saltpetres. In certain cases wall saltpetres result of the incorrect organization of drainage system.
Wall saltpetres are mix of number of chemical compounds among which: carbonate, sodium, potassium, etc. Some are water-soluble, some can be dissolved only under the influence of acids and alkalis. They are formed, mostly, of solution when the ratio of liquid and cement is broken. Wall saltpetres can be shown if cement with the considerable content of water-soluble salts of sodium and potassium has been applied. To emergence of stains on brick can bring also water-soluble salts into raw materials which are used by production of brick.
Alternative reasons of emergence of wall saltpetres
Wall saltpetres can turn out to be consequence of chemical (atmospheric) corrosion, different pollution which have biological origin. If construction was carried out in the megalopolis or near the industrial enterprises, then in these parts the polluted atmosphere, as a rule, is noted. Air contains in the structure the gases forming at considerable humidity of substance among which there is, for example, sulphuric acid. This acid can interact with hydrate of oxide of calcium which contains in solution, the crystal plaster acting as raid on laying as a result can be formed. Can lead precipitation which washes away salts from solution to vysoloobrazovaniye. The pollution taken for wall saltpetres can be residues of cement and cement milk which get on stoneware during inaccurate implementation of construction jobs. If not to get rid of wall saltpetres, then after a while (2-3 years) they are capable to pass into difficult soluble salts. The most effective way which will allow to avoid formation of wall saltpetres is use of quite dense solution which has the insignificant content of oxides of potassium and sodium, the plasticized and hydrophobic cement will allow to replace traditional structure.