Research On Inorganic And Anodic Type Of Antiseptic And Corrosion-inhibiting Admixture For Concrete

Because of the special environment that costal area in, the concrete structures areeasily suffered from sulfate and chloride attack. The erosions greatly impair structuresafety and service life. This research based on the mechanism of sulfate and chloridecorrosion, developed a type of antiseptic and corrosion-inhibiting admixture forconcrete. This admixture is made of dense component, corrosion-inhibiting componentand nitrite. The appearance of the admixture is inorganic powder. It mainly containsfour parts as follwing,1) Based on the mechanism of corrosion, this research selects dense component,corrosion-inhibiting component and nitrite to mix the admixture. According to thereference and result of the task group research, the content range of every component isfixed. The research designs20mixes of a calcium nitrite series of admixture and20mixes of a sodium nitrite series of admixture.2) It is qualified by means of systematical research on specific surface area,setting time, expansion ratio, compressive strength ratio, corrosion resistancecoefficient, expansion coefficient and steel corrosion-resistance of all mixes. Throughthe experiments, the qualified formulas are determined, which satisfy the requirementsof standard JC/T1011-2006regarding “Sulfate Corrosion-Resistance admixture forconcrete” and standard JT/T537-2004regarding “Corrosion inhibitor for reinforcingsteel in concrete”.3) The research select the antiseptic and corrosion-inhibiting admixture mixedwith the content of nitrite8.5%to prepare the concrete and study the influence on theperformances of the concrete added with polycarboxylic-acid and aliphatic waterreducing agent. Compressive strength ratio, resistance of carbonate, transportcoefficient of chloridion, preservative coefficient and the performance ofCorrosion-Resistance are tested in the experiment.4) The research conduct the experiment with XRD and SEM to the concretemixed with antiseptic and corrosion-inhibiting admixture, and observe the influence onthe cement hydration to find out the reason that corrosion-resistance admixtureenstence the anti-permeability and ati-corrosion by sulphate of cement paste. The resultshows that a new kind of antiseptic and corrosion-inhibiting admixture used inconcrete is produced and can remarkably improve the property of anti-sulphate and anti-chloride. The antiseptic and corrosion-inhibiting admixture containing calciumnitriteor the sodium nitrite could omprove the compactedness and anti-permeability ofthe C50concrete mixed with different water reducing agent, and the compressivestrength ratio, resistance of carbonate, transport coefficient of chloridion, preservativecoefficient in experimental group is better than the one in baseline group. consequently,antiseptic and corrosion-inhibiting admixture could be applied withpolycarboxylic-acid or aliphatic water reducing agent.The experiments of XRD and SEM show that,1) compact component’s hydrationconsume the calcium hydroxide to form the CSH gels,2) the antiseptic andcorrosion-inhibiting admixture could reduce the AFm and interrupt the process ofchemical corrosion.