The thesis is devoted to the solution of actual problem of maintenance of durability of concrete in the conditions of sulphate corrosion taking into account temperature of environment. Features of penetration of aggressive substances are considered by introduction of effective coefficient of diffusion in a solid body which reflects influence of parameters of structure of concrete, and also temperature on advance of diffusion ions. Based on Arrhenius' law, the dependence of the diffusion coefficient of ions in liquid solution on temperature and the dependence of the diffusion coefficient of sulfates in concrete on the ambient temperature are obtained. It is established that the diffusion coefficient of ions strongly depends on temperature. At temperatures close to zero, diffusion is practically absent. In the temperature range from 1 to 15 ºC the diffusion coefficient increases intensively. At values of 20-30 ºC, the effect of temperature on the diffusion process becomes less significant. To predict the change in the strength of concrete during sulfate corrosion taking into account the temperature of the environment, an algorithm for predicting the change in the strength of concrete during sulfate corrosion taking into account the temperature of the environment was developed. A mathematical model for predicting the destruction of the protective layer of concrete by reinforcement corrosion products is proposed. The dependences were obtained between the geometric parameters of the structure, the mechanical properties of concrete and the degree of corrosion of the reinforcement, which causes the destruction of the protective layer. The prescription of a rational value of the protective layer of concrete, measures to ensure the design value of the protective layer in the manufacture of reinforced concrete and increase the tensile strength of concrete in the protective layer, along with concrete density, are crucial to increase the durability of reinforced concrete structures. Estimation of the optimal size of the protective layer, made on the basis of the conditions of its destruction of the accumulated corrosion products of reinforcement, coincides with the normalized thicknesses of the protective layers, which are installed on the basis of long-term operation of reinforced concrete structures. The main factors of soil temperature regime formation, which include the processes of heat supply, transfer, accumulation and heat transfer, are analyzed and systematized. The equation of soil heat balance is formulated. Based on the known data on the total thermal balance of the soil surface, an analytical calculation model of soil temperature distribution over depth is proposed. The model considers long-wave radiation, short-wave radiation (solar radiation absorbed by the surface), soil thermal conductivity (soil heat dissipation), convective heat transfer and evaporation effect. To predict the durability of concrete with sulfate corrosion in soils, a calculated model of soil temperature distribution by depth is proposed. Taking into account the temperature distribution along the depth of the soil on the example of Dnipro, isofields of damage to the protective layer of concrete after 10, 50 and 100 years of operation in conditions of sulfate corrosion at a concentration of 15, 30 and 50 g/l were obtained. The assessment of the load-bearing capacity of pile in the conditions of sulfate corrosion was conducted. Theoretical bearing capacity after 100 years of operation decreases by 29 – 33,3 % at a concentration =15–50 g/l, respectively. The results of long-term experimental studies of corrosion resistance of concrete on carbonate aggregates are presented. The content of carbonate sand and dust particles varied in concrete mixtures. A series of samples for comparative analysis, which were kept in water, was prepared separately. A visual inspection and compression test of the samples after 30 years of exposure to a sulfate solution of Na2SO4 with a concentration of 5 % and water. It was found that after 30 years of testing the compressive strength of samples on carbonate sand is 1,7–3,4 times higher than samples on quartz sand. As a result of the numerical experiment, data on the durability of concrete on carbonate aggregates were obtained considering the environment temperature. It was found that the use of carbonate sand as an aggregate leads to a decrease in the predicted depth of damage to 2,3–2,7 cm at a temperature of 25 ºC and a concentration =30 g/l and 3,0–3,5 cm at a concentration =50 g/l; respectively, at a temperature of 15 ºC to 2,1–2,4 cm and 2,7–3,1 cm. Numerical experiment was performed to assess the durability of concrete on carbonate aggregates based on the environment temperature and showed that the use of carbonate sand as an aggregate leads to a decrease in the predicted depth of damage by 22 – 23 %. Keywords: durability, concrete, sulphate corrosion, temperature.
