Research On The Mechanism Of Corrosion Inhibitor Admixture In Reinforced Concrete In Salt Lake Area

This thesis focused on the problem of insufficient durability of reinforced concrete in the salt lake area of Inner Mongolia.Firstly,the mix proportion of sulfate corrosion resistance admixture and corrosion inhibitor obtained in the previous study of the research group was optimized,and then the optimized admixture and corrosion inhibitor were compounded in different proportions to obtain the corrosion inhibitor admixture,which was then mixed into C30.Besides,3.5%Na₂SO₄+6.5%Na Cl solution was selected as the erosion solution to investigate the influence of the corrosion inhibitor admixture on the corrosion resistance and salt freezing resistance of concrete.The mechanism of corrosion inhibitor admixture was analyzed.This is of great significance for taking effective measures to improve the durability of reinforced concrete in the future.The main research works were as follows:（1）Through the mix proportion optimization test of admixture and corrosion inhibitor,the results showed that the super absorbent resin could promote the hydration of cement,it could improve the properties of mortar and cement paste after incorporating an appropriate amount of super absorbent resin.Based on the theory of electrochemical corrosion,using the electrostatic effect of organic corrosion inhibitor and the ion inhibition mechanism of inorganic corrosion inhibitor,it could be concluded that the synergistic effect of organic corrosion inhibitor and inorganic corrosion inhibitor could effectively improve the electrochemical performance of carbon steel sheet and reduce the corrosion rate of carbon steel sheet.（2）According to the corrosion resistance of corrosion inhibitor admixture to concrete and the salt freezing resistance of reinforced concrete,the results showed that the corrosion inhibitor admixture could improve the hydration degree of cement,promote the hydration products combined with Cl^-to form Friedel salt to seal up some pores in the concrete,which could also effectively improve the corrosion resistance of concrete and the salt freezing resistance of reinforced concrete;at the same time,the established concrete mass loss model,relative dynamic elastic modulus damage model and cumulative damage model could better predict the changes of these three properties of concrete after salt freezing.（3）Through the test of Cl^-concentration in concrete,the results indicated that the corrosion inhibitor admixture could effectively reduce the free Cl^-concentration in concrete.Under the action of dry-wet cycles less than 90 times and freeze-thaw cycles,the distribution of Cl^-concentration in concrete conformed to Fick’s second law.After 120 times of dry-wet cycles,the distribution of Cl^-concentration in concrete conformed to the Cl^-transmission model proposed by Balestra.（4）Based on the bubble spacing meter and nuclear magnetic resonance micro performance test,the results illustrated that the corrosion inhibitor admixture could change the internal pore structure of concrete and effectively reduce the content of harmful pores and multi-harmful pores in concrete.When the content of admixture and corrosion inhibitor in corrosion inhibitor admixture was appropriate,and the compactness of concrete could be significantly improved.（5）The results of SEM scanning electron microscope test and EDS spectrum analysis showed that the corrosion inhibitor admixture could promote the hydration of cement,generate a large number of hydration products to refine the internal pore structure of concrete and improve the compactness of concrete.At the same time,the corrosion inhibitor admixture could form a passive film on the surface of steel bars to effectively protect the steel bars from Cl^-erosion and reduce the corrosion rate of steel bars.