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The object of this study was the concrete structures of a chemical enterprise for the production of titanium dioxide. In this case, the ore is decomposed with sulfate acid according to the sulfate production technology. In an aggressive environment, chemical corrosion of concrete occurs, prolonged over time. Using X-ray diffraction and X-ray fluorescence analysis methods, the mineral composition of two prototypes of concrete was determined. It was found that the sample obtained from the workshop for processing ore with sulfate acid showed an increased content of sulfur oxide (SO2) on the surface, by 33%, with a reduced content of carbonates (CaCO3) on the surface, by 52.9%, at a depth of 2cm – by 53.65, compared to another (control) sample. At the same time, iron oxide (Fe2O3) was found on the surface in a sample of concrete from the ore storage room (control), the content of which decreased by 10.4% at a depth of 2cm, and by 12.4% at a depth of 4cm. The results of electron microscopy show sulfur crystals on the surface of a concrete sample. It was also found that the microstructure of concrete was changed under the influence of sulfate corrosion, depending on the intensity of the exposure to a depth of 2 to 4cm. By the method of thermoprogrammed mass spectrometry, it was established that when a sample of concrete exposed to sulfate acid is heated to a temperature of 400°C, sulfur dioxide SO2is released mainly from the surface. From the surface of the control sample, which contains a significant amount of CaCO3, which is easily destroyed by sulfate acid, there is probably a smaller amount of the product of thermal destruction of calcium carbonate carbon dioxide (CO2). The results of the experiment can be used to study the mechanism of development of sulfate corrosion of concrete prolonged over time.

New composite materials were obtained based on chitosan iodide and organic dyes – methylene blue and fuchsine in fucorcin (Castellani liquid) – by using a simple synthetic procedure. The materials were characterised by scanning electron microscopy, X-ray diffraction, temperature-programmed desorption mass spectrometry, infrared spectroscopy and visible and ultraviolet light spectroscopy. The dyes in the composites were distributed uniformly and did not form separate phases. These composites could form structured porous sponges and films and therefore be used in various fields of application. The materials displayed antibacterial activity against antibiotic resistant gram-positive and gram-negative bacteria.

The effect of microbial and chemical corrosion on concrete structures operated in the conditions of chemical enterprises has been established that makes it possible to reliably predict the timing of their decommissioning in order to prevent industrial disasters. Even though the construction complies with all building codes, concrete structures eventually undergo chemical and biological corrosion. The innovation proposed in this study implies investigating the depth and degree of damage to concrete at the microscopic level by the method of raster electron microscopy. In addition, the TPD-MS method has been suggested for determining the quantitative and qualitative state of the carbonate components of concrete and sulfur compounds. This study has found that in concrete samples from the titanium dioxide production plant, the amount of carbon dioxide release is twice less than in control samples at t=600°C while the level of sulfur dioxide, on the contrary, increases. This is due to the ability of thionic bacteria to accumulate sulfate acid that destroys the cementing component in concrete. The reported results confirm the impact of products of the activity of Acidithiobacillus thiooxidans microorganisms on corrosion processes in concrete. In addition, when using the TPD-MS method, it was established in the storage room of the finished product that heating the control sample of concrete leads to a release of the significant amount of СО2at t=580–600°C. However, the experimental samples of concrete are almost lacking carbon compounds because the acid metabolites of microfungi interfere with its formation. Microscopic and REM studies revealed the localization of Acidithiobacillus thiooxidans and Aspergillus fumigatus in concrete. This study has established patterns related to the mechanism that forms chemical compounds in concrete and the metabolism of microorganisms

The object of this study is the regularity of changes in the biogenic destructive effect of microorganisms on the concrete structural elements of livestock facilities due to the use of the original liquid phase mixture of disinfectant based on aldehyde and surfactant. Microorganisms use construction materials as a substrate for growth and nutrition; they produce citric acid, which leads to a change in the composition and morphology of hydrated cement new formations. The composition of the microflora of the pigsty has been determined, and the minimum concentration of disinfectant based on glutaraldehyde and didecyl dimethyl ammonium chloride was found. By the TPD MS method, a decrease in the intensity of carbon dioxide (CO2) release in concrete samples during the heating of the sample to 900°C was proved, compared to the control intact corrosion sample. Electron microscopy of concrete samples shows the presence of destructive changes and colonies of micromycetes. It was established that calcite was intensively released in the control sample of concrete, which retained its integrity and was not subjected to corrosion when heated to a temperature of 600°C. Electron microscopy confirms the preservation of the homogeneous structure of concrete. The use of a disinfectant based on glutaraldehyde and didecyl dimethyl ammonium chloride at a concentration of 1% destroys colonies of micromycetes, 2% – the shell of microorganisms, and 3% – biofilm. Treatment of concrete with a disinfectant at a concentration of 3% destroys microorganisms Aspergillus fumigatus and Penicillium oxalicum, inhibits the process of biological corrosion of concrete, and strengthens the structure of concrete. The results of the experiment can be applied to inhibit the corrosion of concrete and extend the life of building structures made of concrete through the use of a disinfectant based on aldehyde and didecyl dimethyl ammonium chloride at a concentration of 3%.