Studies Of Nano-modification On Enhancing The Chloride Resistance Of Concrete Inorganic Coatings

Coating is one of the important means to improve the resistance of concrete engineering to chloride salt corrosion.However,there are various problems in traditional organic film-forming coatings and inorganic coatings.In order to improve the resistance of traditional concrete inorganic coatings to chloride salts,this paper uses nano-SiO₂ and nano-TiO₂ to modify water glass coatings and cement-based infiltration crystalline coatings,and then prepare nano-modified inorganic coating concrete test pieces.Then,a long-term immersion experiment of Cl^-electric flux and salt solution was carried out on the coated concrete.In addition,microscopic experiments such as scanning electron microscopy?SEM?and mercury intrusion?MIP?were performed on some of the coated samples.The main research results and conclusions are as follows:?1?The type of inorganic coating varies greatly in the degree of improvement in the resistance of concrete to chloride salts.Cement-based coatings significantly improve the resistance of concrete to Cl^-permeation due to its high density,the increase is about 64%⁷4%;while water glass coatings have limited improvement in concrete's resistance to Cl^-permeability due to their poor water resistance and limited water blocking range,the increase is about 0.?2?The resistance of the same nanomaterial to the chloride salts of different inorganic coatings is also significantly different.Nano-modification has little effect on the resistance to Cl^-permeability of water glass coated concrete,but has significant effect on the improvement of cement-based coated concrete,among them,the chloride penetration resistance of 0.5%nano-SiO₂ modified cement-based coating concrete is about 79%higher than that of unmodified cement-based coating concrete.?3?The mechanism of Cl^-permeability resistance of nano-modified cement-based coating concrete is as follows:Firstly,nano-modified cement-based coating forms a dense protective layer on the concrete surface;Secondly,the addition of nanomaterials significantly increased the number of spicules or tendrils on the surface of coated concrete and optimized its surface pore structure.?4?There is a good linear relationship between Cl^-diffusion coefficient y and Cl^-electric flux x of coated concrete:y=0.0072x+3.3446,regression variance R²=0.941;When the content of nano-TiO₂ and nano-SiO₂ is 0.67%and 0.47%respectively,the Cl^-diffusion coefficient of cement-based coated concrete is the smallest;Establishment of life prediction model for Cl^-corrosion resistance of nano modified inorganic coating concrete,and from the results of life prediction,cement-based coatings can significantly prolong the service life of concrete against Cl^-erosion,an increase of26.33 years,and further improve the service life of coated concrete through nano-modification,the largest increase can be 56.73 years.The paper has 36 figures,20 tables,121 references.