Method for measuring chloride ion permeability resistance of concrete

Abstract

The invention discloses a method for measuring chloride ion permeability resistance of concrete. The method comprises the following steps: firstly, soaking a test piece in a standard curing water tankfor 4 days, then putting the test piece into a rubber barrel, injecting about 300mL of a KOH solution with the concentration of 0.2mol / L into the rubber barrel so as to immerse an anode plate and thesurface of the test piece in the solution, injecting a KOH solution having the concentration of 0.2mol / L and containing NaCl with the concentration of 5%, into a test tank until the liquid level is flush with that of the KOH solution in the rubber barrel, turning on power, recording time, immediately and simultaneously measuring the parallel voltage, the serial current, and the initial temperature of an electrolyte (accurate to 0.2 DEG C), taking out the test piece after power off, splitting the test piece into two halves, titrating the diffusion depth of chloride ions by utilizing silver nitrate with the concentration of 0.1mol / L, and finally calculating a chloride ion diffusion coefficient of the concrete according to a formula. With the method, the actual transfer process of the chloride ions can be reflected, measurement can also be carried out in a constant-temperature environment and is not affected by the conductivity of the concrete, and the problem that a detection result byan electric flux method is inaccurate and unreliable is solved.

Description

technical field [0001] The invention relates to the technical field of concrete, in particular to a method for measuring the chloride ion permeability resistance of concrete. Background technique [0002] my country has a vast sea area, and large-scale infrastructure construction is mostly concentrated in coastal areas. Due to the severe chloride ion corrosion of coastal buildings, the corrosion of steel bars is very serious, which is one of the main reasons for durability failure. In recent years, the industry has made a lot of progress in the research on the mechanism of chloride ion erosion damage, model prediction, test detection, preventive repair, etc. The chloride ion permeability test method is used as the detection and evaluation method and objective basis for the main indicator of durability, so it is particularly important to determine an objective, accurate and practical test method. The chloride ion permeability resistance of concrete is one of the important i...

AI Technical Summary

Problems solved by technology

[0003] The existing chloride ion permeability test methods generally use the electric flux method, although the electric flux method is simple and fast, but there are many defects

First of all, the accuracy of the test results is poor, especially for concrete with poor resistance to chloride diffusion. Due to the high voltage applied, the temperature of the solution and the specimen will both rise, and the concrete will be deteriorated, resulting in distortion of the test results.

Secondly, the resistivity of concrete is not only related to the pore structure, but also related to the ionic strength in the pore solution, and the ionic strength has nothing to do with the pore structure; therefore, the test reflects the result of the movement of the overall ions, not just the movement of chloride ions, which ultimately leads to the detection of The results are not accurate and reliable, so we propose a method for measuring the chloride ion permeability of concrete

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