CN101226167B - Method for rapidly measuring reinforcing steel tarnishing criticality chlorine ion concentration - Google Patents

Method for rapidly measuring reinforcing steel tarnishing criticality chlorine ion concentration Download PDF

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CN101226167B
CN101226167B CN2008100578444A CN200810057844A CN101226167B CN 101226167 B CN101226167 B CN 101226167B CN 2008100578444 A CN2008100578444 A CN 2008100578444A CN 200810057844 A CN200810057844 A CN 200810057844A CN 101226167 B CN101226167 B CN 101226167B
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concrete
electric osmose
electrode
test
sample
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CN101226167A (en
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徐永模
耿春雷
翁端
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Tsinghua University
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Abstract

The invention discloses a method for quickly measuring steel bar corrosion critical chloride ion density, belonging to steel corrosion detection technique. The method comprises arranging prepared a concrete sample with a non-immersion reference electrode and an immersion working electrode into an electro-osmosis tank, adding 3-20V direct-current voltages at two sides of the concrete sample, detecting the current of the macro battery composed of the immersion working electrode and the non-immersion reference electrode, if the macro battery current reaches the value of corrosion germination, stopping the electro-osmosis test, or else, continuing and repeating the processes as adding voltage, stopping powering and macro battery current detection until the macro battery current reaches the value of corrosion germination, stopping the electro-osmosis test. And after the electro-osmosis test, the invention uses potential titration to test chloride ion density in concrete. The inventive method can significantly reduce critical chloride ion density test time and realize automatic test control via detecting macro battery current.

Description

A kind of method of fast measuring reinforcing steel tarnishing criticality chlorine ion concentration
Technical field
The invention belongs to steel corrosion degree detecting method field, more particularly, the invention relates to a kind of method of fast measuring reinforcing steel tarnishing criticality chlorine ion concentration.
Background technology
Reinforced concrete is as structural timber, is widely used in the construction work such as highway, bridge, harbour in the chlorine salt corrosion environment.The destroying concrete structure that the reinforcement corrosion that chlorion causes extensively causes, the security that has a strong impact on even jeopardize buildingss such as building construction, bridge.Adopt various high performance concretes, the structure that improve protection level to reinforcing bar in the concrete, corrosion is taken place is keeped in repair repairing have been become when last urgent work.At present, the generaI investigation to the concrete-bridge potential safety hazard is in full swing the progressively foundation of the standard criterion of employing durability index Design of Concrete Structures in China.The reinforcement corrosion criticality chlorine ion concentration be in the decision concrete corrosiveness of the environment size and select concrete material and structure important parameter.
Usually adopt the drying and watering cycle method to measure reinforcing steel tarnishing criticality chlorine ion concentration at present; The shortcoming of the method is that the test duration is long; Though and in the ASTM G109-92 standard macro cell electric current is detected; But can not monitor in real time corrosion cell, can not implement continuous monitoring to corrosion cell simultaneously.The electric osmose test method has been widely used in the coefficient of diffusion of test chlorion in concrete; The general electric osmose voltage that adopts is the 30-60 volt; Its shortcoming is added overtension, in experimentation, can influence test findings at the certain heat of inner generation of concrete time.
Summary of the invention
The objective of the invention is to overcome the shortcoming of prior art, a kind of method of fast measuring reinforcing steel tarnishing criticality chlorine ion concentration is provided.Utilize this method can make the rebar surface chlorine ion concentration reach critical value fast, shorten the criticality chlorine ion concentration minute greatly.
The present invention is achieved through following technical scheme: the concrete sample that comprises non-steeped contrast electrode and immersion working electrode that will prepare; Place the electric osmose pond; The DC voltage that applies lower voltage 3-20 volt on the concrete sample both sides is after a period of time; Stop to power up a period of time, then the macro cell electric current that soaks working electrode and non-steeped contrast electrode formation is detected, (generally adopt 1 μ A/cm if the macro cell electric current reaches the current value of corrosion sprouting 2) time stop electric osmose test, otherwise continue repetition " apply voltage-stop to power up-the macro cell current detecting " process, reach the current value that corrosion is sprouted up to the macro cell electric current, stop the electric osmose test.After the electric osmose off-test, concrete sample is split out from the electric osmose groove, in the drill hole sampling of concrete immersion part, in addition, also the concrete that soaks working electrode surface is taken a sample, adopt the method for potentiometric titration to measure chlorine ion concentration in the concrete.
The present invention has following beneficial effect compared with prior art:
1. to a great extent, reduced chlorion critical concentration minute;
2. can not produce a large amount of heat at inside concrete, can be not influential to experimental result;
3. the criterion that takes place as critical corrosion with the macro cell current value is implemented monitoring to the macro cell electric current, can realize the automatic stepless control of testing.
Description of drawings
Fig. 1 is the concrete sample structural representation
Fig. 2 is an electric osmose pool device synoptic diagram
Fig. 3 is concrete sample sampling synoptic diagram
Fig. 4 is the potentiometric titrimeter synoptic diagram
Embodiment
Below in conjunction with accompanying drawing and embodiment the present invention is described in detail.
1. concrete sample preparation: make concrete sample 1 shown in Figure 1.Chloride solution will be immersed in the lower part of concrete sample 1, and top will be exposed in the air.Non-steeped contrast electrode 2 is connected with copper conductor 4 with immersion working electrode 3, and non-steeped contrast electrode 2 adopts epoxy resin 5 to seal with the side that immersion working electrode 3 is connected with copper conductor 4 and is coated with, and opposite side is exposed in the chloride solution.Concrete sample is after 1 moulding a period of time, and maintenance is carried out in form removal then.
2. installation concrete sample: concrete sample is installed in the electric osmose pond 8 shown in Figure 2, and electric osmose pond 8 is divided into left and right sides two parts, and concrete sample 1 is installed front surface should be clean, no greasy dirt, sand-lime and water.Electric osmose pond 8 left-hand components are used for holding left electric osmose liquid 10, and its composition is 0.2mol/LNaOH; Electric osmose pond 8 right-hand components are used for holding right electric osmose liquid 9, and its composition is 0.2mol/LNaOH+5wt%NaCl, and right electric osmose liquid 9 provides the chlorion of test usefulness; Electric osmose pond lid 7 is used to reduce the evaporation of electric osmose liquid; DC power supply 11 can apply the DC voltage of 3-20 volt through connected positive plate 12 and 13 pairs of concrete samples 1 of negative plate; Chlorion under effect of electric field to soaking working electrode 3 surface seepages; Soak working electrode 3 and constitute macro cell with non-steeped working electrode 2, thermometer 5 is used for measuring the temperature variation of electric osmose pond 8 right-of-center in political views's electric osmose liquid 9.
3. electric osmose test: DC power supply 11 applies the DC voltage of 3-20 volt through connected positive plate 12 and 13 pairs of concrete samples 1 of negative plate; In the electric osmose process of the test; The temperature variation of right electric osmose liquid 9 can be controlled in 20 ± 0.2 ℃ the scope; Stop then powering up, measure in the concrete sample 1 the macro cell current value between two electrodes with the zero resistance amp gauge.If the electric current of being surveyed also surpasses the current value that corrosion is sprouted, then system continues repetition " apply voltage-stop to power up-the macro cell current detecting " process, reaches the current value that corrosion is sprouted up to the macro cell electric current, stops the electric osmose test.
4. chlorine ion concentration is measured: concrete sample 1 is split out from electric osmose pond 8; After the concrete surface drying, near boring 14 (as shown in Figure 3) the immersion working electrode 3 of the immersion of concrete sample 1 part, with the powder of holing as sampling; The drilling depth of each sampling is 10mm ± 1mm; In addition, also the concrete on electrode 3 surfaces is taken a sample, powdered sample separates preservation.Powdered sample is taken by weighing the weight quality to the constant weight and is M through drying, to be measured.Device shown in Figure 4 is adopted in potentiometric titration; In titration cell 17, dripping phenolphthalein indicator 3-5 drips; Dropwise add salpeter solution then, use magnetic stirring apparatus 19 to cooperate magnetic stirring bars 16 constantly to stir simultaneously and heat, when solution becomes redness never again; Stop to add salpeter solution, this moment the chlorion in the concrete powder is dissolved into to generate in the solution and waits to drip solution 15.Drip with concentration C in titration cell 17 by titration apparatus 22 then AgNO3Liquor argenti nitratis ophthalmicus, and make contrast electrode 21 with saturated calomel electrode, make indicator electrode 18 with silver electrode, the potential difference (PD) that adopts pot 20 to measure between indicator electrodes 18 and the contrast electrode 21, and the volume V of the record potential difference (PD) and the liquor argenti nitratis ophthalmicus that consumes AgNO3, the V of correspondence when serving as zero with the secondary difference quotient AgNO3Value, both be add the volume of silver nitrate when breasting the tape.The content of cement is C% in the concrete, then the chlorine ion concentration D in the concrete Cl-(by mass of cement percentage composition) is:
D Cl - = V AgN O 3 × C AgNO 3 × 35.5 1000 × M × C % × 100 % - - - ( 1 )
Chloride ion content is as causing the Rust of Rebar in Concrete criticality chlorine ion concentration in the concrete on employing electrode 3 surfaces.Better the present invention is explained through embodiment below.
Embodiment 1
In certain test, be 6.9g in the concrete of the electrode surface concrete powder quality that obtains of taking a sample, employed silver nitrate concentration C AgNO3=0.01mol/l, the cement content C%=17.58% in the concrete, and the volume relationship of the liquor argenti nitratis ophthalmicus of current potential of measuring during titration and consumption and one-level thereof, secondary difference quotient are as shown in the table:
V AgNO3 Potential difference (PD) E/mV ΔE/ΔV(mV/ml) ΔE 2/ΔV 2(mV/ml 2)
0.0 211.0 ? ?
2.0 221.0 5 ?
4.0 248.4 13.7 4.35
5.5 281.8 22.3 5.73
6.0 289.3 15.0 -14.6
8.0 312.5 11.6 -1.7
10.0 321.6 4.5 -14.2
Calculate corresponding to secondary difference quotient Δ E with interpolation method 2/ Δ V 2V when being zero AgNO3Value
V AgNO 3 = 5.5 mL + 0.5 mL × ( 5.73 mV / ml 2 5.73 mV / ml 2 + 14.6 mV / ml 2 ) = 5.64 mL
According to formula (1), can calculate D again Cl-Be 0.165%, the critical concentration that promptly causes corrosion in the concrete is 0.165%).

Claims (2)

1. the method for a fast measuring reinforcing steel tarnishing criticality chlorine ion concentration; It is characterized in that; Will be on the top of concrete sample fixing non-steeped contrast electrode, the fixing working electrode that soaks in the bottom of concrete sample, two electrodes are connected with copper conductor and are placed in the electric osmose pond; Chloride solution will be immersed in the lower part of its concrete sample; Top will be exposed in the air, and non-steeped contrast electrode adopts epoxy resin to seal with the side that the immersion working electrode is connected with copper conductor and is coated with, and opposite side is exposed to and constitutes macro cell in the chloride solution; Concrete sample is divided into left and right sides two parts with the electric osmose pond, and the left side, electric osmose pond holds the NaOH electric osmose liquid that composition is 0.2mol/L; The right holds the NaOH+5wt%NaCl electric osmose liquid that composition is 0.2mol/L; Apply DC voltage 10-60 minute of lower voltage 3-20 volt on the concrete sample both sides after; Stop to power up; After 10-60 minute, the macro cell electric current that soaks working electrode and non-steeped contrast electrode formation is detected, if the macro cell electric current reaches the current value 1 μ A/cm that corrosion is sprouted 2The time stop electric osmose test, otherwise continue repetition " apply voltage-stop to power up-the macro cell current detecting " process, reach the current value 1 μ A/cm that corrosion is sprouted up to the macro cell electric current 2, stop the electric osmose test; After the electric osmose off-test, concrete sample is split out from the electric osmose groove, in the drill hole sampling of concrete immersion part, in addition, also the concrete that soaks working electrode surface is taken a sample, adopt the method for potentiometric titration to measure chlorine ion concentration in the concrete.
2. according to the method for the said fast measuring reinforcing steel tarnishing criticality chlorine ion concentration of claim 1, it is characterized in that concrete steps are following;
1) concrete sample is installed: concrete sample (1) is installed in the electric osmose pond (8), and electric osmose pond (8) are divided into left and right sides two parts, and concrete sample (1) is installed front surface should be clean, no greasy dirt, sand-lime and water; Electric osmose pond (8) left-hand component is used for holding left electric osmose liquid (10), and electric osmose pond (8) right-hand component is used for holding right electric osmose liquid (9), and right electric osmose liquid (9) provides the chlorion of test usefulness; Electric osmose Chi Gai (7) is used to reduce the evaporation of electric osmose liquid; DC power supply (11) can apply DC voltage to concrete sample (1) through connected positive plate (12) and negative plate (13); Chlorion under effect of electric field to soaking working electrode (3) surface seepage; Soak working electrode (3) and non-steeped working electrode (2) and constitute macro cell, thermometer (5) is used for measuring the temperature variation of electric osmose pond (8) right-of-center in political views's electric osmose liquid (9);
2) electric osmose test: DC power supply (11) applies the DC voltage of 3-20 volt to concrete sample (1) through positive plate (12) and negative plate (13); In the electric osmose process of the test; The temperature variation of right electric osmose liquid (9) can be controlled in 20 ± 0.2 ℃ the scope, stops then powering up, with the macro cell current value between two electrodes in the zero resistance amp gauge measurement concrete sample (1); If the electric current of being surveyed does not also surpass the current value that corrosion is sprouted; Then system continues repetition " apply voltage-stop to power up-the macro cell current detecting " process, reaches the current value that corrosion is sprouted up to the macro cell electric current, stops the electric osmose test;
3) chlorine ion concentration is measured: concrete sample (1) is split out from electric osmose pond (8); After the concrete surface drying, near boring (14) the immersion working electrode (3) of the immersion of concrete sample (1) part, with the powder of holing as sampling; The drilling depth of each sampling is 10mm ± 1mm; In addition, also the concrete on electrode (3) surface is taken a sample, powdered sample separates preservation; Powdered sample is taken by weighing weight to the constant weight and is M through drying, to be measured; In titration cell (17), dripping phenolphthalein indicator 3-5 through titration apparatus (22) drips; Dropwise add salpeter solution then; Use magnetic stirring apparatus (19) to cooperate magnetic stirring bar (16) constantly to stir simultaneously and heat, when solution becomes redness never again, stop to add salpeter solution; This moment the chlorion in the concrete powder is dissolved into to generate in the solution and waits to drip solution (15), drip with concentration C in titration cell (17) by titration apparatus (22) then AgNO3Liquor argenti nitratis ophthalmicus; And make contrast electrode (21) with saturated calomel electrode; Make indicator electrode (18) with silver electrode, adopt pot (20) to measure the potential difference (PD) between indicator electrode (18) and the contrast electrode (21), and the volume V of the record potential difference (PD) and the liquor argenti nitratis ophthalmicus that consumes AgNO3, the V of correspondence when serving as zero with the secondary difference quotient AgNO3Value, both be add the volume of silver nitrate when breasting the tape, the content of cement is C% in the concrete, then the chlorine ion concentration D in the concrete C1-(by mass of cement percentage composition) is:
D Cl - = V AgN O 3 × C AgNO 3 × 35.5 1000 × M × C % × 100 %
Adopt chloride ion content conduct causing Rust of Rebar in Concrete criticality chlorine ion concentration in the surperficial concrete of electrode (3).
CN2008100578444A 2008-02-19 2008-02-19 Method for rapidly measuring reinforcing steel tarnishing criticality chlorine ion concentration Expired - Fee Related CN101226167B (en)

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CN101666721B (en) * 2009-09-28 2011-11-16 浙江大学宁波理工学院 Method for rapidly measuring deactivation removal chloridion threshold of reinforcing steel bar in concrete
CN102253101B (en) * 2011-05-06 2013-03-27 山东鸿瑞石油化工有限公司 Method for detecting chloride ions in polyisobutylene
CN102854163B (en) * 2011-06-28 2015-06-03 鞍钢股份有限公司 Method for measuring content of chloride ions on surface of cold-rolled steel plate or steel strip
CN102359931A (en) * 2011-09-19 2012-02-22 东南大学 Concrete fatigue load and environmental coupling experiment apparatus
CN103376277A (en) * 2012-04-23 2013-10-30 中冶建筑研究总院有限公司 Method for evaluating corrosion situations of steel reinforcement
CN103424434B (en) * 2013-08-21 2015-08-26 国家电网公司 Soft clay consolidation by electroosmosis experimental technique under anode follow-up effect
CN104374813B (en) * 2014-10-31 2017-02-08 南京钢铁股份有限公司 Method for determining concentration of critical chloride ion in concrete reinforcing bars
CN105301176A (en) * 2015-11-03 2016-02-03 衢州巨化锦纶有限责任公司 Analysis method of industrial chlorosulfonic acid
CN106680180B (en) * 2017-01-16 2023-05-23 华南理工大学 Device, method and application for monitoring migration quantity of chloride ions across concrete
CN107192640B (en) * 2017-07-12 2023-10-03 广西路桥工程集团有限公司 Concrete soaking test device
CN109358098B (en) * 2018-12-25 2021-02-26 垒知控股集团股份有限公司 Method for testing concentration of chloride ions on surface of cement-based material

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CN1438478A (en) * 2003-03-20 2003-08-27 上海交通大学 Method for detecting corrosion of concrete bar in reinforced concrete
JP2005274498A (en) * 2004-03-26 2005-10-06 Sumitomo Osaka Cement Co Ltd Method for measuring amount of chlorine ions
CN101071132A (en) * 2006-05-11 2007-11-14 上海市建筑科学研究院有限公司 Concrete chloride ion permeation property quick rust testing method

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1438478A (en) * 2003-03-20 2003-08-27 上海交通大学 Method for detecting corrosion of concrete bar in reinforced concrete
JP2005274498A (en) * 2004-03-26 2005-10-06 Sumitomo Osaka Cement Co Ltd Method for measuring amount of chlorine ions
CN101071132A (en) * 2006-05-11 2007-11-14 上海市建筑科学研究院有限公司 Concrete chloride ion permeation property quick rust testing method

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