ON THE PROBLEM OF AMMONIA EMISSION FROM REINFORCED CONCRETE STRUCTURES OF RESIDENTIAL BUILDINGS
The harmful effects of ammonia on the human body include damage to the respiratory tract, the mucous membranes of the eyes, nose and mouth, and the skin. Prolonged exposure to ammonia vapors causes convulsions, dizziness, suffocation, loss of consciousness, circulatory disorders, and muscle weakness. For adults, the potentially dangerous dose of ammonia is higher than for children. "Ammonia houses" were found among new buildings in St. Petersburg, Moscow, Nizhny Novgorod, as well as in China, Japan, Finland and other countries. The article reviews the reasons for the release of ammonia from concrete and reinforced concrete products and structures. The main sources of ammonia are various chemical additives introduced into concrete to improve the properties, which include urea and ammoniated fly ash. Although the requirements do not limit the ammonium content, using such material as an additive for cement composites causes the emission of gaseous ammonium during mixing and from the final product. In general, it takes more than 10 years to completely remove ammonia from a concrete wall containing urea-based antifreeze. Methods for determining the content of ammonia in concrete and indoor air are listed. Ammonia detection is facilitated using filter packs and fabric denuders (a gas separator). An overview of ways to accelerate and prevent the release of ammonia from concrete is given. The most common method of reducing the concentration of ammonia in the indoor air is ventilation. A high rate of air exchange leads to a decrease in the concentration of ammonia, and an increase in temperature causes an increase in the concentration of ammonia and its volatilization rate.