Chlorine ion curing agent for reinforced concrete and preparation method and applications thereof

Abstract

The invention belongs to the technical field of chlorine ion curing agents, and especially relates to a chlorine ion curing agent for reinforced concrete and a preparation method and applications thereof. The curing agent is metal dihydroxide with a layered structure, has a micro-nano level granular shape, and is prepared by compounding 50 to 80 parts by weight of CaFe-NO3LDHs and 20 to 50 parts by weight of CaFeAl-NO3LDHs. The prepared chlorine ion curing agent does not damage a cement based material, and can stably and efficiently adsorb chlorine ions in a simulated concrete hole solution. In a cement paste sample, which has been soaked in a sodium chloride solution (3.5%), the corrosive performance of chlorine ions is obviously reduced, the effect is excellent, and the provided chlorineion curing agent is efficient and stable.

Description

technical field [0001] The invention belongs to the technical field of chloride ion curing agents, in particular to a chloride ion curing agent for reinforced concrete and its preparation method and application. Background technique [0002] The information disclosed in the Background of the Invention is only intended to increase the understanding of the general background of the invention, and is not necessarily to be taken as an acknowledgment or any form of suggestion that the information constitutes the prior art that is already known to those skilled in the art. [0003] Free chloride ions (Cl - ) is easy to cause deterioration of reinforced concrete structure and performance, endangering the safety, reliability and service life of the project. This is mainly manifested as: when chloride ions enter the concrete, it will promote the electrochemical corrosion of steel bars (anode: Fe→Fe 2+ +2e - ; Cathode: O 2 +2H 2 O+4e - →4OH - ). When the corrosion of steel bar...

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Problems solved by technology

Also, since C 3 A high early hydration heat release, leading to internal heating of the concrete, which is especially unfavorable in marine concrete structures

[0005] (2) Sacrificial anode cathodic protection method: the cost of replacing steel bars required by cathodic protection method in this method is relatively high

[0006] (3) Epoxy-coated steel bars: Although the organic coating has good water resistance and toughness, its anti-aging and anti-wear capabilities are poor, resulting in a low service life

In addition, the adhesion and toughness of the inorganic coating to the steel bar are poor, which makes the coating on the surface of the steel bar easy to fall off, thereby causing corrosion of the steel bar.

[0007] (4) Apply concrete rust inhibitors; although inorganic rust inhibitors can form a consistent oxide film on the surface of steel bars, when the concentration of the rust inhibitor is lower than the concentration required for its own film formation, it will accelerate the corrosion of steel bars by chloride ions

[0008] In addition, the patent document CN200810030796.X discloses an admixture for improving the performance of cement-based materials in solidifying free chloride ions and its use method. The admixture has a good effect in curing chloride ions. The mass ratio of mineral and nitrite is 8-9:1. Mixing and mixing into cement materials can significantly improve the chloride ion curing ability of cement-based materials, but the dosage is as high as 25-35% of cement-based materials, and the cost is high. Nitrite has a certain degree of toxicity, and large doses are harmful to the human body

[0009] Patent document CN201410465488.5X discloses a chloride ion curing agent and its use method. The admixture also has good chloride ion curing properties and is an intercalation product of Ca-Al-LDH and water reducer (Ca-Al-SP -LDH) composite, its dosage is 2 to 5% of the mass of the cementitious material, through ion exchange to achieve the curing of chloride ions, which can improve the chloride ion penetration resistance of reinforced concrete to grades I to II, but in simulated concrete The desorption rate of Ca-Al-LDH obtained in the pore solution is high, and it is very easy to react with sulfate in the solution to form a large number of ettringite crystals, which reduces its curing effect and volume stability

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