Calculation method of chloride ion concentration in concrete under chlorine salt-corrosion effect

A technology of chloride ion concentration and calculation method, applied in the field of calculation of chloride ion concentration in concrete under the action of chloride salt-dissolution

Active Publication Date: 2020-12-04
NANJING UNIV OF SCI & TECH
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Problems solved by technology

[0004] The object of the present invention is to provide a kind of calculation method of chloride ion concentration in concrete under the action of chlorine salt-dissolution, which solves the problem of free chloride ion concentration in concrete under complex water environment And combined with the calculation of chloride ion concentration, it is of great significance to predict the corrosion damage of steel bars in concrete and evaluate the service life of concrete structures under the corrosion-chlorine salt attack water environment

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  • Calculation method of chloride ion concentration in concrete under chlorine salt-corrosion effect
  • Calculation method of chloride ion concentration in concrete under chlorine salt-corrosion effect
  • Calculation method of chloride ion concentration in concrete under chlorine salt-corrosion effect

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Embodiment 1

[0068] Quantitative calculation of chloride ion concentration in concrete under the action of corrosion-chloride salt is now carried out, and the relevant main parameters are selected as follows:

[0069] Material parameters: Concrete is composed of the following raw materials by mass: 100 parts of cement, 55 parts of water, 200 parts of sand, 257 parts of aggregate, the cement is PO52.5 ordinary Portland cement, the sand is medium sand, and the aggregate is 5~ 20mm gravel;

[0070] Component parameters: concrete slab thickness is 200mm;

[0071] Environmental parameters: the ambient temperature is 25°C, the calcium ion concentration in the ambient water is C w-Ca 0mol / m 3 , the concentration of chloride ions in ambient water C w-Cl 500mol / m 3 , ion exchange rate K v0 6×10 -7 m / s, the diffusion coefficient of chloride ion in pure water is 2.03×10 -9 m 2 / s, the diffusion coefficient of calcium ions in pure water is 7.92×10 -10 m 2 / s.

[0072] Step 1: Determine the i...

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Abstract

The invention discloses a calculation method of chloride ion concentration in concrete under chlorine salt-corrosion effect. The calaculation method can describe the diffusion behavior of calcium ionsand chloride ions in the concrete under corrosion-chlorine salt erosion water environment, and quantitatively calculate the concentrations of free chloride ions and bound chloride ions in the concrete under the corrosion-chlorine salt effect. The method comprises the following steps: firstly, establishing an expression of free and combined chloride ion concentration in concrete under the action of chlorine salt-corrosion; and then establishing a coupling transmission model of chloride ions and calcium ions in the concrete under a water saturation condition according to the Fick law, the massconservation law and a solid-liquid balance relationship of calcium in the pore solution, and carrying out numerical solution by utilizing a finite difference method to obtain concentrations of free and combined chloride ions in the concrete at different erosion times. The method solves the calculation problem of the concentration of the free chloride ions and the concentration of the bound chloride ions in the concrete in a complex water environment, and is of great significance to prediction of corrosion damage of steel bars in the concrete in a corrosion-chlorine salt erosion water environment and evaluation of the service life of a concrete structure.

Description

technical field [0001] The invention belongs to the field of durability analysis of concrete structures, and in particular relates to a method for calculating the concentration of chloride ions in concrete under the action of chlorine salt-dissolution. Background technique [0002] In water conservancy projects such as dams, ports, water delivery tanks and bridges, concrete structures have been subject to coupled erosion of chloride salts and calcium dissolution in environmental water for a long time, resulting in reduced durability of concrete structures and shortened service life. Among them, the chlorine ions in the ambient water penetrate the surface of the steel bar through the concrete protective layer and reach a certain concentration, which will cause the passivation film on the surface of the steel bar to be depassivated, and the steel bar will be corroded. Calcium dissolution will lead to the dissolution of calcium hydroxide, C-S-H gel and calcium sulfoaluminate mo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N17/00G06F30/23
CPCG01N17/00G06F30/23
Inventor 李向南左晓宝
Owner NANJING UNIV OF SCI & TECH
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