Study Of Corrosion And Protection Of Marine Reinforced Concrete Construction

Reinforced concrete in marine engineering environment is impacted by the sea salt and humid environmental, and easily caused to corrosion. Carbonation reduces the pH value of concrete, and destructed the alkaline environment. Aggressive chloride ions competitive adsorbs active sites of steel surface, makes the surface of the passive film damaged, causes corrosion of reinforcement, which reduces the durability of building structures. Exploring the law of the corrosion behavior of reinforced concrete, in order to develop effective protective measures as the field of reinforced concrete has became hot spots.Firstly this paper examined the effect of chloride ion content and the value of pH on the corrosion behavior of carbon steel in simulated solution of concrete pore. It draws conclusions that:With the increasing of chloride ion content or decreasing of the pH value, corrosion of carbon steel tend to increase; when the value of pH is12.5, carbon steel has no significant evidence of corrosion, impedance decreased with increasing concentration of sodium chloride equilibrium potential gradually shifted negatively, the current density increased; when the pH value is11, as sodium chloride concentration greater than or equal to0.5%, carbon steel has pitting corrosion, gradual negative shift with increasing concentration of sodium chloride, the equilibrium potential, current density increased; what’s more, with the lower pH value, the equilibrium potential of carbon steel decreased, the current density increased; when the pH value is8, carbon steel is caused to general corrosion, and the current density are higher. When the pH value is9.5, there are obvious signs of pitting on the carbon steel, current density are higher; when the pH is11and12.5, carbon steel has no significant evidence of corrosion.Secondly, this paper examines the protective properties of octyl triethoxysilane on concrete surface. By the water absorption test, the freeze-thaw cycle test, the contact angle of observation and electrochemical test methods, it draws conclusions that:octyl triethoxysilane molecules adsorb on the surface of wall in concrete pore by dehydration condensation to form a silicone resin layer containing hydrophobic (-C8H17). After treatment by octyl triethoxysilane, the concrete surface has significant hydrophobic effects, which inhibit water and aggressive chloride ion penetration, and have greater resistance to freeze-thaw cycle destruction.Finally, this article also discusses effect to the corrosion behavior of carbon steel in simulated solution of concrete pore by adding the inhibitor Urotropine. It draws conclusions that:when the sodium chloride concentration is2%and3.5%, it has good inhibition effect in amount of0.2%-0.4%and0.05%-0.4%respectively.The passive current of Q235carbon steel decreases,Ep is higher,and corrosion is inhibited.