EXPERIMENTAL METHOD OF AMIDE NITROGEN CONCENTRATION DETERMINING IN CONSTRUCTION MATERIALS

The article actualizes the environmental problem of ammonia emission in industrial and residential buildings into the indoor air environment. In the process of studies it has been established that the main sources of ammonia emission into the indoor air are concrete structures (concrete walls, ceilings, columns, etc.) and finishing materials. In concrete, ammonia is formed as a result of hydrolysis of urea (NH2)2CO contained in concrete, and urea (urea) and other similar substances are used as hardening gas pedals and anti-freeze additives, including ammonized fly ash. It is possible to prevent ammonia emission into the indoor air not only by checking construction materials for cases of exceeding the maximum permissible concentration of urea in them, but also by experimental determination of amide nitrogen concentration in concrete mixtures at the stage of their delivery to construction sites. The aim of the article is to present an experimental technique to determine amide nitrogen concentration in construction materials developed to control amide nitrogen concentration at the stage of concrete mixture delivery to construction sites to exclude ammonia formation after putting construction sites of different functional purposes into operation. Experimental method for determining the concentration of amide nitrogen in building materials is the result of solving the following research tasks: – examination of building materials by methods of physical and chemical analysis for the quantitative determination of amide nitrogen; – comparison of the obtained results with the data of research laboratories with the conclusions about the quality of performed analyses. Approbation of the proposed experimental method for determining the concentration of amide nitrogen in building materials was carried out in the laboratory of the test center «OOO«Settle City» in Kudrovo.