Page 42 - Автореферат Греділь М.І.

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The anisotropy of corrosion resistance has been revealed for reinforcing cold-
drawn pearlite wires, which manifested in a higher polarisation resistance of their side
surface compared to the cross-section. The regularities and the mechanism of the

corrosion-mechanical fracture of the wires at the intermediate stages of the cold drawing
process have been established. Contrary to the first three stages of cold drawing, where
the crack is initiated from the side surface and gradually propagates through the wire
cross-section, at the later stages, another crack origin appears in the centre of the wire
due to residual tensile stresses, with further coalescence of two crack paths.
The factors of bond strength degradation in reinforced concrete during its long-
term operation have been elucidated and modelled by applying the external current to a
reinforced concrete specimen to speed up electrochemical processes at the rebar surface.
The method is developed for assessing bond strength in reinforced concrete under the
action of corrosive-hydrogenating environments. It is based on the determination of

bond strength parameters under the tensile testing of a cylindrical concrete specimen
reinforced with two coaxially placed rebar rods, one of which is subjected to cathodic
polarisation. It evidenced a significant impact of hydrogen evolution on adhesive
strength in reinforced concrete due to hydrogen embrittlement of steel and concrete
cover exfoliation.

Keywords: steel, corrosion, corrosive environment, hydrogen, hydrogen
charging, hydrogen embrittlement, damage, operational degradation.