Two heterocyclic oximes (E)-N-hydroxy-1-(pyridin-2-yl)methanimine (Hp2ylm) and (E)-N-hydroxy-1-(pyridin-3-yl)methanimine (Hp3ylm) were synthesized from pyridine-2-carbaldehyde and pyridine-3-carbaldehyde, respectively. These oximes were characterized by various spectroscopic tools like UV, IR, MASS and NMR. The inhibition capacity of these oximes against copper corrosion in 0.1 M HNO3 was determined by polarization and impedance spectroscopic studies (EIS). At all concentrations, Hp3ylm exhibited higher inhibition efficiency than Hp2ylm. Attempt was made to illustrate the mechanism of corrosion inhibition by these oximes with the help of adsorption isotherm, scanning electron microscopic (SEM) and quantum chemical studies.

In this research, an investigation was carried out through experimentation and numerical modeling to evaluate the cracking pressure induced due to corrosion of reinforcement for different cover thicknesses, grades of concrete and bar locations. The model was also used to determine the patterns of crack for a different number of bars and the effect of bar diameter on cracking pressure. The critical pressure was measured experimentally by applying hydraulic pressure through a hole in concrete cubes of 150 mm. Abaqus 6.14 was used as a modeling platform. From the experimentation and numerical modeling, it was found that with the increase of cover thickness the critical pressure was increased irrespective of bar locations. A lower cracking pressure was observed for corner bar with respect to the sidebar. On the other hand, with the increase in bar diameter, a decrease in cracking pressure was observed. The critical pressure observed was also increased with higher grades of concrete. For corner bars with cover thickness 37.5 mm, the critical pressure was found as 6-10 MPa and it increased up to 17 MPa for the cover thickness of 64 mm for different grades of concrete. On the other hand, for other bar location with the cover thickness of 37.5 mm and 64 mm, the pressure required to initiate crack was about 7.6 MPa and 14.8 MPa, respectively, for C20 grade concrete.

The article is devoted to some aspects of research of hostile environment influence on the concrete durability. The mechanism of formation of chaotically diversified difficult structure is described. Chemical interactions of cement with active components of diffusion in steam space are examined. Measures for receiving conditions under which the volume of products of reaction will be equal to the volume of the reacted alkaline components of a cement stone are offered. High-quality and quantitative changes in a pore space, which are irrespective of density and the relative molecular mass of reaction products are described. Besides, movement and distribution of gaseous products of reaction in volumes of a cement stone are simulated. Reasonable integrated dependences of influence of aggressive environment on various types of concrete surfaces are given. The methods of corrosion control offered in article allow substantially to lower or absolutely to exclude adverse effect of hostile environment on concrete and reinforced concrete structures already at a stage of selection of composition of concrete mix. In this case service life of concrete and reinforced concrete structures will increase.