calcium silicate bricks defectsAmong the common building materials (excluding polymers), silicate brick is one of the youngest. Its technology was developed at the end of the 19th century, but mass production and use began in the middle of the last century. We are considering what it looks like, said brick, the pros and cons of this building material. Before we examine in detail the advantages and disadvantages of silicate brick, it is necessary to know what kind of material it is in terms of technology. Silicate brick is almost identical to the natural material limestone, which has been used for over a thousand years. But, as you know, natural stone is almost always much more expensive (including delivery costs) than synthetic. Experiments with a mixture of lime and sand began almost simultaneously by the Russian civil engineer Prokhov and the Swedish Ridin, they tried to industrialize build walls, and even whole houses from it, because it is understandable to achieve high quality It was impossible. , Portland cement-based concrete was already widely used). A little further, the German doctor (not the manufacturer!!!) Bernardi moved, he made compacted bricks which then hardened in air. But the products did not have proper moisture resistance. A fellow doctor (also a doctor, but in the field of chemistry) Michaelis tried to process a mixture of lime and sand with pressurized steam. So there was a silicate brick. Moreover, his invention was not based on calculations, but the result of trial and error. 
The process of making silicate bricks is very simple (unlike the production of other building materials), but it requires special equipment. Therefore, silicate is only produced industrially. It is unprofitable to make it in small workshops. It should also be noted that the production of silicate bricks is very close to the production of foam blocks and gas silicate. Therefore, factories often produce the entire range, and the same autoclaves are used to heat treat the lines. This is due to the fact that cheap raw materials such as lime and sand are used (albeit of extremely high quality). You can also use sharp CHPP steam that is cooled in cooling towers to produce such bricks Such a brick is more environmentally friendly and does not contain harmful components. In terms of the level of radioactive radiation, it is generally at a minimum background value compared to not only natural but also artificial building materials.Although it is not inferior in frost resistance to ceramics, silicate begins to decompose with constant exposure to water. Therefore, it is not used for the soles of the feet. In addition, often during heavy rains, silicate brick walls are soaked with water, so that the humidity inside the house also increases. Some of the bricks become stained after being placed in the wall, which is due to the presence of iron salts, and this problem mostly happens when the brick is saturated with water in storage or during work. 
calcium silicate bricks problems
Also, unlike ceramics, silicate does not withstand high temperatures. Therefore, it cannot be used for chimneys, and even more so for fire boxes. It can collapse unpredictably from sudden heating and cooling, or continuous exposure to flames or flue gases.Lack of smooth shapes and decorative elements High water absorption The water absorption of silicate brick can reach 7-8%. which does not allow this material to be used for the construction of various elements in which the humidity has increased. This type of whitewash is created when the brick is made from brackish soil or there is brackish water and sand in the mortar. Dandruff is salty and in humid air it absorbs water vapor and the wall becomes damp and after it dries, the dander that has appeared appears on the wall in the form of white nitrate. Contamination of bricks with substances such as urine, fertilizers, and some plants that contain nitrates also causes dandruff. The permanent proximity of brickwork with nitrated materials and water causes the appearance of calcium nitrate, which causes the mortar to loosen and the continuous increase in humidity, which leads to the disintegration of the mortar and the deterioration of the work. 
First, it is necessary to take a sample of the whitewash very carefully so as not to scratch the wall and identify its type, then identify the source of the whitewash, which is usually the leakage of underground water and rainwater, and take measures to prevent water penetration into the brick work, and then He cleaned the whitewash from the facade surfaces. Dandruff and dandruff are often in the form of fine fibrous crystals and can be easily cleaned with a wire brush or grass broom. If the surface of the walls still does not have a good appearance after brushing, it is better to wash it with clean water and brush it again and rinse it again. If the appearance of the work is still not good, the surface of the wall should be completely wet with water and a solution of 1 to 9 hydrochloric acid should be used to clean the white carbonate and then the wall should be rinsed. The sudden appearance of dandruff and whitewash on the surfaces of the walls is often due to the penetration of moisture. Green scales should be cleaned with a brush dipped in sodium hydroxide solution with a concentration of 300 grams per liter. This action causes white salt deposits to form on the wall, which can be washed off with water after three days. Also, these stains can be removed with ethylene diamine tetraacetic acid (EDTA) solution with a concentration of one part in 10 parts of water, but the use of hydrochloric acid to remove such stains is not only ineffective, but also causes its stabilization and turns its color into It turns brown. 
If, in addition to the whitewash, the bricks, mortars, or coatings on the walls are corroded or cracked, these defects should be removed first and the wall should be washed well. Spraying one to three coats of soluble bitumen (one part of pure bitumen with a penetration degree of up to 100 and three parts of kerosene) on a clean and dry wall and coating it with cement-sand mortar has a favorable result.