Method for testing diffusion coefficient of chloride ions in concrete through bending load function

Abstract

The invention provides a method for testing a diffusion coefficient of chloride ions through a bending load function. The method comprises the steps of firstly testing the bending strength of a set ofconcrete testing members, mounting the testing members after vacuum saturation in a loading device, performing uniform loading on the testing member through controlling the change of a spring lengthin the loading device by a press, then mounting a diffusion pool of a stable state electromigration experiment device on a loaded concrete testing member, after checking the sealing between a diffusion pool and the testing member and confirming good sealing, adding pre-prepared solution, and finally connecting with a stable DC power supply and testing the content of the chloride ion. When the measured accumulated concentration of the chloride ions and the diffusion time are in a linear relation, the diffusion coefficient of the top chloride ions in the concrete is calculated. The method realizes synchronous testing for a chloride ion transmission process through the bending load function. The concentration change and diffusion rate of the chloride ions can be timely detected. Furthermore the diffusion coefficient of the chloride ion can be quickly calculated. The voltage can be autonomously adjusted according to the characteristic of the concrete.

Description

technical field [0001] The invention belongs to the technical field of structural concrete durability, and in particular relates to a method for testing the diffusion coefficient of chloride ions in concrete under the action of bending load. Background technique [0002] The corrosion of steel bars induced by chloride ions is one of the main factors for the failure of structural concrete. Therefore, domestic and foreign researches on the transmission process of chloride ions in concrete, the damage evolution law of reinforced concrete under chloride-salt environment, life prediction and the method of reducing the permeability of chloride ions Protective measures, etc. These research contents all involve the test method of its concentration evolution law and transmission coefficient during the transmission process. [0003] In the past few decades, many test methods for measuring the chloride ion diffusion coefficient of concrete under no load have been proposed at home and a...

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Problems solved by technology

In the national standard, the ASTMC1202 electric flux method can only qualitatively evaluate the permeability of concrete. The RCM method can still be used for low-volume mineral-mixed concrete, but when a large amount of mineral admixture is mixed in cement or concrete, the silver nitrate titration method It is impossible to distinguish and analyze the penetration depth of chloride ions, coupled with the randomness of concrete pore distribution, the penetration depth of chloride ions cannot be tested, so the RCM non-steady-state diffusion coefficient method is not suitable for the modern concrete test method currently widely used; steady-state Electromigration test is currently widely used in the world, but the applied voltage is also up to 60V. For low-strength grade concrete, the volatilized concentration of the solution is often changed due to the excessively high applied voltage, so the application range is limited.

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