Method for measuring resistance of concrete to chloride ion permeability

A technology of chloride ion penetration and measurement method, which is applied in the field of civil engineering material performance testing, can solve problems such as prolonging the test time, affecting test results, and changing test time, achieving fast measurement speed, scientific and reliable principles, and overcoming polarization reactions Effect

Inactive Publication Date: 2019-08-02
QINGDAO TECHNOLOGICAL UNIVERSITY
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Problems solved by technology

[0006] 0.3mol / L NaOH and 3% NaCl solution, after the specimen is saturated with water in vacuum, a 60V direct current voltage is applied to both ends, Cl- will accelerate the diffusion under the action of the electric field and the concentration difference, and measure the total amount passing through the concrete specimen within 6 hours Electricity (coulomb), the total electric quantity is related to the permeability of Cl-, the greater the electric quantity passing through the specimen per unit time, the greater the permeability of the concrete; this method is easy to operate, but the extremely high DC voltage of 60V is applied. The chemical reaction will increase the temperature of the solution and affect the test results. If the test voltage is lowered, the test time will be greatly prolonged; the RCM method is a version of the German chloride ion electromigration rapid test method, and has been successively adopted by Switzerland. SLA262 / 1-2003 standard and German BAW standard draft (2004.05) adopted
After years of development, the RCM method is internationally recognized as one of the more accurate test methods for measuring the chloride ion diffusion coefficient in an unsteady state. Although it is simple, practical, and accurate, it requires that the aggregate particle size of the specimen must not More than 25mm, the packaging process is cumbersome, and the test time varies with different specimens; in addition, the test equipment used by Shi Meilun to evaluate the diffusion resistance of ions in it by AC impedance spectroscopy is expensive and the test steps are complicated.

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  • Method for measuring resistance of concrete to chloride ion permeability
  • Method for measuring resistance of concrete to chloride ion permeability
  • Method for measuring resistance of concrete to chloride ion permeability

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Embodiment 1

[0046] The concrete chloride ion permeability measurement method involved in this embodiment is realized on the concrete chloride ion permeability measurement device. The specific process includes making concrete specimens, pretreating concrete specimens, clamping concrete specimens, measuring concrete There are five steps in the resistance of the specimen and the calculation and analysis of the permeability of the concrete specimen:

[0047] (1) Making concrete specimens: when the concrete specimens are cast-in-place, pour three cylindrical concrete specimens with a diameter of 100 mm and a thickness of 50 mm. Cured in water at 20±3°C until the test age is 28 days, when the concrete specimen is drilled in the solid concrete structure, cut 50mm inward from the surface of the concrete core sample to form a concrete specimen with a diameter of 100mm, and cut 3 pieces of the same size Concrete test pieces, if there is paint on the surface of the concrete test piece, the paint sho...

Embodiment 2

[0061] The method for measuring the chloride ion permeability resistance of concrete by the concrete chloride ion permeability measuring device involved in this embodiment is called the alternating current measurement method, and the concrete specimens prepared in the laboratory are respectively used for chloride ion penetration by the alternating current measurement method and the electric flux method. For performance measurement, the concrete specimen prepared in the laboratory is made of ordinary Portland cement with P.O 52.5, river sand with a fineness modulus of 3.12, and crushed stones with a continuous gradation of 5-20mm, produced by Jiangsu Subote New Materials Co., Ltd. The polycarboxylate high-efficiency water reducer and Qingdao local tap water are used as raw materials. According to the water-cement ratio of 0.6, the cement is 300kg / m 3 , stone 1191kg / m 3 , sand 699kg / m 3 , water 160kg / m 3 , Water reducer 1.11kg / m 3 Three cylindrical specimens with a diameter o...

Embodiment 3

[0069] The method for measuring the chloride ion permeability resistance of concrete by the concrete chloride ion permeability measuring device involved in this embodiment is called the alternating current measurement method. For ion permeability measurement, the mix ratio of the concrete core specimen is: water-cement ratio 0.32, cement 470kg / m 3 , stone 1044kg / m 3 , river sand 726kg / m 3 , water 151kg / m 3 , Admixture 5.17kg / m 3 , the test age is 210 days and 212 days, the AC resistance test is carried out first, and then the electric flux method test is carried out:

[0070] When the age was 210 days, the representative value of AC resistivity was 1626.56Ω·m according to the measured value of AC resistance and the specifications of the specimen, and the evaluation result according to the evaluation standard in Table 1 was very low; the representative value of electric flux was 162C, according to the evaluation standard in Table 1. The evaluation result of the evaluation s...

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Abstract

The invention belongs to the technical field of a civil engineering material performance test method and relates to a method for measuring resistance of concrete to chloride ion permeability. The method is realized through a device for measuring resistance of concrete to chloride ion permeability, and comprises the following specific five steps: preparation of a concrete test sample, pretreatmentof the concrete test sample, clamping of the concrete test sample, measurement of resistance of the concrete test sample and calculation and analysis of permeability of the concrete test sample. A low-voltage high-frequency alternating current with voltage of 1 v and frequency of 1000 hz is adopted to measure the resistance of the concrete test sample obtained after saturated water pretreatment, and the resistance value reflects the resistance of the concrete test sample to chloride ion permeability, thereby overcoming the disadvantages of the polarization reaction easily existed in a direct current test method and interference on the resistance value caused by heat generated by the solution under long-time voltage action, and improving ASTM C1202 recommended by the American society for testing materials. The method is scientific and reliable in principle, simple in measuring process, fast in measuring speed, accurate in measuring results, and easy to be popularized and used.

Description

[0001] Technical field: [0002] The invention belongs to the technical field of performance testing methods of civil engineering materials, and relates to a method for measuring the chloride ion permeability resistance of concrete, which directly and quickly measures the chloride ion permeability resistance of concrete based on alternating current. [0003] Background technique: [0004] During the service life cycle of concrete structural components in construction engineering, under the influence of freeze-thaw, carbonation, acid-base corrosion or alkali-aggregate reaction, the use function and structural safety will be destroyed; since the 1960s , the durability of concrete has attracted more and more attention from experts and scholars, and it is one of the issues that cannot be ignored in the current civil engineering field; after years of research, it has been found that various failure mechanisms that affect the durability of concrete are related to the permeability of c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N15/08
CPCG01N15/08
Inventor 万小梅韩林赵铁军张鹏崔祎菲郭思瑶姜福香金祖权申晨范宏王鹏刚尚君侯东帅尹暖暖
Owner QINGDAO TECHNOLOGICAL UNIVERSITY
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