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CN105738273B - The test method and experimental rig of reinforcing bar nature non-uniform corrosion in simulation concrete - Google Patents

The test method and experimental rig of reinforcing bar nature non-uniform corrosion in simulation concrete Download PDF

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CN105738273B
CN105738273B CN201610129924.0A CN201610129924A CN105738273B CN 105738273 B CN105738273 B CN 105738273B CN 201610129924 A CN201610129924 A CN 201610129924A CN 105738273 B CN105738273 B CN 105738273B
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reinforcing bar
corrosion
stainless steel
steel wire
concrete
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CN105738273A (en
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付传清
梁坚凝
金贤玉
裴华富
金南国
刘佳敏
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Zhejiang University of Technology ZJUT
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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Abstract

The accelerated test method and device of reinforcing bar nature non-uniform corrosion in simulation concrete, the method is included in pre-buried stainless steel wire in concrete, and carries out constant current energization to concrete test block, carries out cell reaction;The device includes die unit, forcing unit, test block to be measured and energization unit.The die unit includes the mold for pouring test specimen to be measured, through-hole bolt and fastening bolt;The forcing unit includes holder, lower fulcrum, upper fulcrum, load screw rod and puller bolt;The test block to be measured includes concrete substrate, reinforcing bar and stainless steel wire electrode;The energization unit uses voltage stabilization and current stabilization DC power supply.The beneficial effects of the invention are as follows:Test period is short, can effectively simulate reinforcing bar nature non-uniform corrosion;And it can effectively control the reinforcing bar along the circumferential direction position of uneven corrosion, corrosion range and corrosion degree, and the uneven corrosion along reinforcing bar length direction;Reduce the energy loss generated due to concrete resistance, prediction result accuracy is high.

Description

The test method and experimental rig of reinforcing bar nature non-uniform corrosion in simulation concrete
Technical field
The present invention relates to the test methods and experimental rig of reinforcing bar nature non-uniform corrosion in a kind of simulation concrete.
Background technology
Due to advantage of the concrete structure in terms of materials, cost, maintenance, occupy predominantly in civil engineering always Position, has a very wide range of applications in great civil engineering (large-scale construction engineering, science of bridge building, water conservancy project and harbor work's engineering). Concrete structure under marine environment and deicer salts environmental condition, reinforcement corrosion are to influence the master of concrete structure durability Want factor.No matter the economic loss caused by concrete structure durability is brought to developed country or developing country Huge economic loss, has caused extensive concern both domestic and external.Concrete cover rust distending is caused to split for steel bar corrosion Research, emerged a large amount of achievement.Experimental study is the deep supplementary means of theoretical research, and experimental technique determines The accuracy of experimental study.
Steel bar corrosion can generate splitting stresses to concrete, thus lead to concrete cracking to reduce the clothes of concrete structure Use as a servant performance.The influence that different reinforcing bars, concrete and corrosion degree split concrete rust distending is studied to be of great significance.For mixed Xtah Crude Clay structure becomes rusty the research of swollen dehiscence process, and currently used test method mainly has:Natural rust method, artificial environment accelerate Bubble method and energization accelerating corrosion method based on electrochemistry.
Natural rust method usually requires to establish natural erosion exposure station in marine environment, by reinforced concrete member or contracting Ruler structural model is placed in natural erosion environment, and Rust of Rebar in Concrete situation is detected or is detected in different time, from And acquire the proficiency data of steel bar corrosion under natural conditions.However, the projected life of reinforced concrete structure is under normal conditions Decades even upper a century, will study the steel bars corrosion problem of concrete structure whole life cycle, need that several generations' is common Effort, it is clear that cannot meet the needs of improving design method.Therefore, mixed using the lower concrete material of strength grade or reduction Solidifying protective soil layer thickness is widely used in the method for accelerating steel bar corrosion rate.There is many difficult, hardly possible using natural rust method To obtain systematic research achievement in a short time.
Environmental condition is to influence an important factor for etching medium transmission is with steel bar corrosion rate in concrete.In order to improve certainly The deficiency of right bubble method, increases the feasibility of experiment, passes through the biography of artificial climate Environmental Law accelerated erosion medium in laboratory It is defeated, to achieve the purpose that shorten the steel bar corrosion time, and then establish the relationship of artificial acceleration corrosion and natural rust.This method is still So mechanism based on natural rust, used accelerated erosion method mainly have:Concentration, the environment temperature of etching medium are improved, And the saturation degree etc. by salt mist environment or drying and watering cycle enhancement of environment inside concrete.It is obtained by artificial climate Environmental Law The data taken have good reference value to the method or model of establishing for the prediction of concrete structure service life, when experiment Between be usually some months to several years time, the test period is still longer, and manual simulation's environmental test chamber cost is higher, still The extensive development of limit assay research.
As it can be seen that according to the natural law that steel bar corrosion develops, the test method based on natural rust can only be in a certain range Interior acceleration steel bar corrosion rate shortens research cycle.Electrochemical electrolysis principle is applied to and accelerates Rust of Rebar in Concrete examination It tests, establishes the energization accelerating corrosion method based on electrochemistry, undoubtedly greatly shorten the effective way of test period.It is powered and accelerates rust Etching method is will to wait for that Corrosion Reinforcement as anode, makees cathode, in conjunction with the more of concrete material with stainless steel or copper sheet in concrete Permeability feature, using the hole solution in concrete as medium, by controlling current strength and conduction time, according to Faraday's law, The target corrosion amount of artificial control reinforcing bar.Since current flow method has Speed of steel Corrosion fast, easily controllable extent of steel corrosion Advantage, therefore be widely used in steel bar corrosion experiment.However, according to electrochemical principle, by armored concrete structure Part, which is placed in saline solution, carries out energization accelerating corrosion, and reinforcing bar can be made to generate uniform corrosion, this under natural conditions towards mixed The fact that solidifying protective soil layer is concreteed cracking on one side occur semi-moon shaped corrosion first and lead to protective layer while is not inconsistent.Obviously, Achievement in research based on this test method cannot be effectively used for reinforced concrete structure durability prediction.
So-called non-uniform corrosion is primarily present two kinds of situations:(1) for the swollen dehiscence process of the rust for studying concrete, usually Armored concrete is sliced, is studied as plane strain problems.Etching medium reaches rebar surface under the conditions of natural rust Causing removing blunt of reinforcing steel bar, steel bar corrosion rate is controlled by oxygen transmission.When concrete rust distending is split, towards protective layer one side Reinforcing bar only has a small amount of corrosion.Also that is, reinforcing bar non-uniform corrosion is that there are non-homogeneous rust along reinforcing bar circumferencial direction under natural conditions Erosion;(2) concrete is a kind of porous heterogeneous material.Therefore, on along reinforcing bar length direction, the corrosion in each corrosion section Rate is stochastic variable, and corrosion degree size depends on the porosity size of concrete.Along reinforcing bar length direction, there are non-homogeneous Corrosion.Research contributes to the data for counting the random corrosion of reinforcing bar, is held for structure along the non-uniform corrosion of reinforcing bar length direction Carry power forecast analysis.
Chinese patent application publication No. CN101762453A, data of publication of application are on June 30th, 2010, entitled " built-in The accelerated test method of reinforcing bar non-uniform corrosion in electrode simulation concrete ", Chinese patent Authorization Notice No. CN101782500B, " the accelerated test of reinforcing bar non-uniform corrosion in external electrode simulation concrete that authorized announcement date is on November 2nd, 2011, entitled Method " makes reinforcing bar accelerate to generate non-uniform corrosion in two pieces patent application using electric osmosis principle.Although the method is in certain journey The non-uniform corrosion of reinforcing bar can be realized on degree, but reinforcing bar cannot be made to generate along the non-uniform corrosion of reinforcing bar circumferencial direction and along reinforcing bar The non-uniform corrosion of length, and iron rust cannot be made to result from towards concrete cover side, it cannot really reflect natural rust Corrosion form caused by being transmitted to rebar surface due to chlorion, oxygen and moisture.And according to electrochemical theory, electrode and steel The distance between muscle is remoter, and the resistance of concrete is bigger, to generate larger fuel factor, causes generally to use Faraday's law Predict that the prediction result of steel bar corrosion amount is inaccurate.
As it can be seen that find a kind of test period it is short, it is at low cost, can reinforced concrete be non-effectively under simulating natural environment The accelerating corrosion method of uniform corrosion simultaneously establishes corresponding test device, improves using the accurate of Faraday's law prediction corrosion amount Property, cause deepening continuously for concrete structure degeneration research most important steel bar corrosion.
Invention content
The purpose of the present invention is overcoming the prior art, provide a kind of period it is short, it is at low cost, can quickly generate steel Muscle non-uniform corrosion, can effectively in simulation concrete reinforcing bar nature non-uniform corrosion test method and experimental rig.
The test method of reinforcing bar nature non-uniform corrosion, includes the following steps in simulation concrete of the present invention:
1) preparation of mold:Stainless steel wire through mold side and is locked, and the both ends of stainless steel wire are fallen in mould Except tool, after the rate of tension and length of adjusting stainless steel wire, it will wait for that the reinforcing bar of corrosion is mounted in mold;Described is stainless Steel wire determines whether its surface is arranged insulating layer according to test objective;
2) concrete sample is prepared:Casting concrete in a mold, form removal after 1 day age, then supports concrete sample Protect plan age;Wherein first loosen stainless steel wire before form removal;
3) constant current energization corrosion:According to expected corrosion ratio or rusty scale thickness distribution, sets electrical current and calculate energization Time;Stainless steel wire one end is connect with constant voltage dc source cathode, will wait for Corrosion Reinforcement and voltage stabilization and current stabilization DC power anode Connection opens voltage stabilization and current stabilization DC power supply and is powered, sets electrical current size, records electrical current and conduction time is powered Corrosion after reaching estimated conduction time, closes power supply;
4) reinforcing bar rusty scale thickness is calculated according to formula (1):Between rusty scale thickness and current density, conduction time and angle Relational expression:
In formula, TrFor rusty scale spreading depth (mm);I is corrosion electric current density (A/mm2);R is reinforcing bar radius (mm);T is logical Electric time (s);θ is angle;When the determination of reinforcing bar radius, as long as effectively control corrosion rate current density i and conduction time t, can make Reinforcing bar reaches expected corrosion ratio, and can predict rusty scale thickness T of the rusty scale of non-uniform Distribution at angle, θr
The experimental rig of the test method structure of reinforcing bar nature non-uniform corrosion in simulation concrete as described in the present invention, It is characterized in that:Including die unit, forcing unit, test specimen to be measured and energization unit, the test specimen to be measured is mounted in described In the mold of die unit, embedded reinforcement and stainless steel wire, the forcing unit are stuck in be measured inside the test specimen to be measured On the stainless steel wire of test specimen;The anode of the energization unit and the reinforcing bar of test specimen to be measured are electrically connected, and the energization unit is born Pole and the stainless steel wire of test specimen to be measured are electrically connected;
The die unit includes the mold and through-hole bolt for pouring test specimen to be measured, and symmetrical two sides of mold are pre- Remain for through the first hole of reinforcing bar and for the second hole through stainless steel wire;The through-hole bolt and described the Two holes are spirally connected, and the company of exocoel in mold is realized in being axially arranged with for the perforative through-hole of stainless steel wire for the through-hole bolt It is logical;The through-hole bolt head is equipped with the first puller bolt for preventing stainless steel wire from bouncing back;
The forcing unit includes holder and load screw rod, and the holder includes first connecting rod, second connecting rod, described The front end of first connecting rod is equipped with the upper fulcrum for being stuck on stainless steel wire, the end of the first connecting rod and described second Connecting rod is hinged;The front end of the second connecting rod is equipped with the lower fulcrum for being stuck on stainless steel wire, the second connecting rod End and the first connecting rod are spirally connected to form triangle geometry with load screw rod respectively, pass through the load screw rod tune Corner dimension between whole first connecting rod and second connecting rod;
The test specimen to be measured includes concrete substrate, reinforcing bar and stainless steel wire, and the reinforcing bar is parallel with stainless steel wire to be buried It is placed in inside concrete substrate;
The energization unit uses voltage stabilization and current stabilization DC power supply, and the reinforcing bar electricity of the anode of DC power supply and test specimen to be measured Even, the cathode of DC power supply and the stainless steel wire of test specimen to be measured are electrically connected.
The mold includes bed die and rectangle side form, and the side form is surrounded by two panels L-type steel plate, and two panels L-type steel plate is first Tail is affixed by fixing bolt;And the L-type steel plate of the side form is fixed on by fastening bolt on bed die.
It is respectively provided with for the preformed hole across stainless steel wire on the upper fulcrum and the lower fulcrum, wherein upper fulcrum Preformed hole at the second puller bolt for being useful for fixed stainless steel wire.
The test block to be measured is honeycombed cement sill, waits for that the reinforcing bar of corrosion and stainless steel wire have different-diameter and section Product ratio, determines whether stainless steel wire surface is arranged insulating layer according to test objective, to realize along reinforcing bar length or along reinforcing bar length With the non-uniform corrosion of circumferencial direction, and by determining the clear distance of reinforcing bar and stainless steel wire to realize the corrosion of reinforcing bar circumferencial direction Area size.
Indoor 220V alternating currents are converted to voltage stabilization and current stabilization DC power supply by the energization unit, and control DC voltage 0~ 30V。
The accelerated test method of reinforcing bar nature non-uniform corrosion in simulation concrete of the present invention, operation principle and The prediction technique of non-uniform corrosion rusty scale thickness distribution is as follows:
A electrochemical principles
In electrolytic cell, oxidation reaction occurs for anode betatopic, and cathode obtains electronics and reduction reaction occurs.Due to the fortune of electronics Dynamic speed is more than the reaction speed of electrode, and cathode generates electron rich phenomenon.When annode area is far longer than cathode area, if cloudy Pole is smaller with a distance from anode, and due to coulomb active force, the anode part closer from cathode, electronics is acted on preferential along conducting wire by repulsion It loses, metal ion is preferentially entered hole solution by graviational interaction, and the form of expression is that anode generates uneven corrosion.
In the present invention, Corrosion Reinforcement is waited for as anode, and stainless steel wire is as cathode.
B constant current principles
Using traditional energization corrosion test method, the target corrosion region of energization corrosion is the whole table area of reinforcing bar, And under field conditions (factors), before crack, there is semi-moon shaped corrosion first on one side towards protective layer in reinforcing bar, backwards Protective layer not corrosion substantially on one side.According to natural rust form, this method think reinforcing bar stainless steel wire and its tangential extent Corrosion inside first occurs, tangent line angle is maximum corrosion regional extent.According to Faraday laws, quality is damaged caused by steel bar corrosion Lose Δ wsIt is represented by:
In formula, MFeFor the atomic weight of iron, 56g/mol is taken;T is conduction time (s);ZFeFor the chemical valence of iron, 2 are taken;F is Faraday constant (C/mol);I is added size of current (A).
Assuming that happens is that uniform corrosion, corrosion ratio ρ, then caused by steel bar corrosion in reinforcing bar maximum corrosion regional extent Mass loss Δ wsIt can be expressed as again:
Vws=A0ρLγs
In formula, A0(mm is accumulated for reinforcing bar original section2);ρ is average corrosion rate;L is steel bar corrosion segment length (mm);γsFor Reinforcing bar density, takes 7.85 × 10-3g/mm3
The relationship of conduction time and corrosion ratio can be established:
But it is tested according to the present invention, rusty scale is unevenly distributed in maximum corrosion regional extent.Establish polar coordinate system, it is assumed that Rusty scale thickness maximum central angle is 0, and angle is to be just clockwise, it is believed that rusty scale is distributed as when concrete cracking:
In formula, TrFor rusty scale spreading depth (mm);a1For the nonuniformity coefficient of rusty scale;a2It is rusty scale along the expansion of reinforcing bar perimeter Coefficient is opened up, θ is angle.
By rusty scale distribution formula it is found that rusty scale area AsFor:
Wherein, α is the angle of tangent line and stainless steel wire-reinforcing bar circle center line connecting.
Before concrete cracking, the outer reinforcing bar not corrosion of angle [- α, α] range, rusty scale thickness TrIt is 0.Therefore
And As=n ρ A0, n is the iron rust coefficient of expansion, generally takes 2.26~3.00.
I.e.It is final to obtain a by changing member1=n ρ A0
According to a2Meaning, it is known that a2It is related with two diameter of reinforcing bar ratio, distance variables to stainless steel wire.
Relationship between electrical current and current density is:
I=α r2Li
To sum up obtain the predictor formula of rusty scale thickness distribution:
The statistical result of the naturally uneven corrosion of reinforcing bar, when concrete cover is just split, rusty scale central angle can reach 120 Degree, there is a at this time2=0.444.
Therefore, the relational expression that can be reduced between rusty scale thickness and current density, conduction time and angle:
When the determination of reinforcing bar radius, as long as effectively control corrosion rate current density i and conduction time t, can make reinforcing bar reach pre- Phase corrosion ratio, and can predict rusty scale thickness T of the rusty scale of non-uniform Distribution at angle, θr
By built-in stainless steel wire electrode, and the diameter for controlling stainless steel wire may be implemented annode area and be much larger than cathode Area, and control the two poles of the earth distance, reinforcing bar nature non-uniform corrosion that can effectively in simulating reinforced concrete.Pass through change Stainless steel wire can effectively control steel at a distance from reinforcing bar, the diameter ratio of the quantity of stainless steel wire electrode, stainless steel wire and reinforcing bar The muscle along the circumferential direction position of uneven corrosion, corrosion range and corrosion degree.By being carried out along its length to stainless steel wire Minor insulation processing, can effectively control the uneven corrosion along reinforcing bar length direction;Stainless steel wire is at a distance from reinforcing bar to be become rusty Closely, the little energy of concrete resistance consumption, can greatly improve and calculate the essence that steel bar corrosion loses quality using Faraday laws Exactness;Through-hole bolt is arranged at die unit both ends, and is provided with puller bolt on through-hole bolt, can effectively, easily be fixed With loosen stainless steel wire.Loading unit uses simple triangle geometry relationship, is increased by the angle changed between two sides The length on Article 3 side, it is simple in structure to realize stainless steel wire tensioning.
Specifically, in the simulation concrete experimental rig of reinforcing bar nature non-uniform corrosion application method, including Following steps:
1) preparation of mold:Through-hole bolt is screwed into the second hole of mold by assembly mold, and stainless steel wire passes through through-hole The axially extending bore of bolt runs through mold in turn, and the first puller bolt of through-hole bolt head is utilized to fix stainless steel wire, stainless steel Silk one end sequentially passes through the upper lower fulcrum preformed hole of forcing unit after being pierced by through-hole bolt, and is held out against by second at upper fulcrum Bolt fixes locking, and mold, stainless steel wire and forcing unit is made to form a self-balancing system, and the rotation of rotation urging unit adds Screw stretching stainless steel wire is carried, twists the puller bolt on the through-hole bolt of mold forcing unit side after stainless steel wire tensioning Tightly, it prevents from bouncing back to fix stainless steel wire;Forcing unit is removed after cutting extra stainless steel wire, finally penetrates and waits for corrosion steel Muscle;
2) preparation of concrete sample:Casting concrete in a mold, form removal after 1 day age;First loosen mold before form removal Puller bolt on two side through hole bolts, to loosen stainless steel wire, by concrete sample form removal maintenance to plan age;
3) constant current energization corrosion:According to expected corrosion ratio or rusty scale thickness distribution, sets electrical current and calculate energization Time;Stainless steel wire is connect with constant voltage dc source cathode, will wait for that Corrosion Reinforcement is connect with voltage stabilization and current stabilization DC power anode, It opens voltage stabilization and current stabilization DC power supply to be powered, sets electrical current size, record electrical current and conduction time carries out energization corrosion, After reaching estimated conduction time, power supply is closed.
The present invention can control reinforcing bar along the uneven corrosion of circumferential direction by changing the relative position of steel wire and reinforcing bar Position, can also pass through to steel wire carry out minor insulation adhesive tape package carry out Axinlly nonuniform corrosion.
Beneficial effects of the present invention are mainly manifested in:
1. by built-in stainless steel wire electrode, and annode area may be implemented much larger than the moon in the diameter for controlling stainless steel wire Pole-face accumulates, and controls the two poles of the earth distance, reinforcing bar nature non-uniform corrosion that can effectively in simulating reinforced concrete, and tests It is at low cost, easy to operate, the test period is short.
2. by change stainless steel wire at a distance from reinforcing bar, the quantity of stainless steel wire electrode, stainless steel wire and reinforcing bar it is straight Diameter ratio can effectively control the reinforcing bar along the circumferential direction position of uneven corrosion, corrosion range and corrosion degree.
3. by carrying out minor insulation processing along its length to stainless steel wire, can effectively control along reinforcing bar length direction Uneven corrosion.
4. stainless steel wire is close at a distance from reinforcing bar to be become rusty, the little energy of concrete resistance consumption can greatly improve utilization Faraday laws calculate the accuracy of steel bar corrosion loss quality.
It, can effectively, easily 5. through-hole bolt is arranged at die unit both ends, and is provided with puller bolt on through-hole bolt Fix and loosen stainless steel wire.
6. loading unit uses simple triangle geometry relationship, Article 3 is increased by the angle changed between two sides The length on side, it is simple in structure to realize stainless steel wire tensioning.
Description of the drawings
Fig. 1 is cell reaction principle schematic in the concrete of the present invention (wherein, I indicates that electric current, V indicate voltage);
Fig. 2 is that (21 represent corrosion region to the uneven corrosion diameter schematic diagram of reinforcing bar circumferencial direction of the invention;211 represent rust Layer boundary;212 represent reinforcing bar contour line before corrosion;213 represent corrosion after reinforcing bar contour line wherein, r indicate reinforcing bar original radius, D indicates that the clear distance between stainless steel wire and reinforcing bar, α indicate the maximum angle of corrosion layer and the reinforcing bar center of circle-stainless steel wire line);
Fig. 3 is the mode host visual pattern of the present invention;
Fig. 4 is the mold vertical view of the present invention;
Fig. 5 is the mold right view of the present invention;
Fig. 6 is the forcing unit structure chart of the present invention;
Fig. 7 is the upper fulcrum enlarged drawing of the forcing unit of the present invention;
Fig. 8 is the lower fulcrum enlarged drawing of the forcing unit of the present invention;
Fig. 9 is the concrete sample schematic diagram of the present invention;
Figure 10 is the concrete sample side view of the present invention;
Figure 11 is to be powered to accelerating the iron rust distribution in the circumferential direction of non-uniform corrosion reinforcing bar.
Specific implementation mode
It further illustrates the present invention below in conjunction with the accompanying drawings
With reference to attached drawing:
The test method of reinforcing bar nature non-uniform corrosion in 1 simulation concrete of the present invention of embodiment, including it is following Step:
1) preparation of mold:Stainless steel wire through mold side and is locked, and the both ends of stainless steel wire are fallen in mould Except tool, after the rate of tension and length of adjusting stainless steel wire, it will wait for that the reinforcing bar of corrosion is mounted in mold;Described is stainless Steel wire determines whether its surface is arranged insulating layer according to test objective;
2) concrete sample is prepared:Casting concrete in a mold, form removal after 1 day age, then supports concrete sample Protect plan age;Wherein first loosen stainless steel wire before form removal;
3) constant current energization corrosion:According to expected corrosion ratio or rusty scale thickness distribution, sets electrical current and calculate energization Time;Stainless steel wire one end is connect with constant voltage dc source cathode, will wait for Corrosion Reinforcement and voltage stabilization and current stabilization DC power anode Connection opens voltage stabilization and current stabilization DC power supply and is powered, sets electrical current size, records electrical current and conduction time is powered Corrosion after reaching estimated conduction time, closes power supply;
4) reinforcing bar rusty scale thickness is calculated according to formula (1):Between rusty scale thickness and current density, conduction time and angle Relational expression:
In formula, TrFor rusty scale spreading depth (mm);I is corrosion electric current density (A/mm2);R is reinforcing bar radius (mm);T is logical Electric time (s);θ is angle;When the determination of reinforcing bar radius, as long as effectively control corrosion rate current density i and conduction time t, can make Reinforcing bar reaches expected corrosion ratio, and can predict rusty scale thickness T of the rusty scale of non-uniform Distribution at angle, θr
The conduction time of step 3 calculates according to formula (2):
In formula, t is conduction time (s);ZFeFor the chemical valence of iron, 2 are taken;F is Faraday constant (C/mol);MFeFor iron Atomic weight takes 56g/mol;I is added size of current (A);A0(mm is accumulated for reinforcing bar original section2);L is steel bar corrosion segment length (mm);γsFor reinforcing bar density, 7.85 × 10 are taken-3g/mm3;ρ is average corrosion rate.
The test method structure of reinforcing bar nature non-uniform corrosion in 2 simulation concrete as described in Example 1 of embodiment Experimental rig, including die unit, forcing unit, test specimen to be measured and energization unit, the test specimen to be measured are mounted in the mould In the mold for having unit, embedded reinforcement 2 and stainless steel wire 3, the forcing unit are stuck in be measured inside the test specimen to be measured On the stainless steel wire of test specimen;The anode of the energization unit and the reinforcing bar of test specimen to be measured are electrically connected, and the energization unit is born Pole and the cathode of test specimen to be measured are electrically connected;
The die unit includes the mold and through-hole bolt 7 for pouring test specimen to be measured, symmetrical two sides of mold It is pre- to remain for through the first hole 9 of reinforcing bar 2 and for the second hole 10 through stainless steel wire 3;The through-hole bolt 7 with Second hole 10 is spirally connected, and mould is realized in being axially arranged with for 3 perforative through-hole of stainless steel wire for the through-hole bolt 7 The connection of exocoel in tool;7 head of through-hole bolt is equipped with the first puller bolt 11 for preventing stainless steel wire 3 from bouncing back;
The forcing unit includes holder 13 and load screw rod 16, and the holder 13 includes first connecting rod, second connecting rod, The front end of the first connecting rod is equipped with the upper fulcrum 15 for being stuck on stainless steel wire, the end of the first connecting rod and institute The second connecting rod stated is hinged;The front end of the second connecting rod is equipped with the lower fulcrum 14 for being stuck on stainless steel wire, described The end of second connecting rod and the first connecting rod are spirally connected with load screw rod 16 respectively, are adjusted by the load screw rod 16 Corner dimension between first connecting rod and second connecting rod;
The test specimen to be measured includes concrete substrate 1, reinforcing bar 2 and stainless steel wire 3, and the reinforcing bar 2 and stainless steel wire 3 are flat Row is embedded in inside concrete substrate 1;
The energization unit uses voltage stabilization and current stabilization DC power supply 4, and the reinforcing bar of the anode and test specimen to be measured of DC power supply 4 2 are electrically connected, and the cathode of DC power supply 4 and the stainless steel wire 3 of test specimen to be measured are electrically connected.
The mold includes bed die 6 and rectangle side form, and the side form is surrounded by two panels L-type steel plate 5, two panels L-type steel plate 5 Head and the tail are affixed by fixing bolt;And the L-type steel plate 5 of the side form is fixed on by fastening bolt 8 on bed die 6.
It is respectively provided with for the preformed hole across stainless steel wire 3 on the upper fulcrum 15 and the lower fulcrum 14, wherein With the second puller bolt 17 for being useful for fixed stainless steel wire at the preformed hole of upper fulcrum 15.
The test block to be measured is honeycombed cement sill, waits for that the reinforcing bar of corrosion and stainless steel wire have different-diameter and section Product ratio, determines whether stainless steel wire surface is arranged insulating layer according to test objective, to realize along reinforcing bar length or along reinforcing bar length With the non-uniform corrosion of circumferencial direction, and by determining the clear distance of reinforcing bar and stainless steel wire to realize the corrosion of reinforcing bar circumferencial direction Area size.
Indoor 220V alternating currents are converted to voltage stabilization and current stabilization DC power supply by the energization unit, and control DC voltage 0~ 30V。
Embodiment 3 is below to measure the ratio of mud 0.53, match ratio as cement:Water:Sand:Coarse aggregate=1:0.53:2.0: 3.0 concrete for energization corrosion, illustrates the work of the present invention after built-in stainless steel wire.
The raw material of the embodiment mixing concrete are:Cement is 52.5 class a portland cement of P.I, and sand uses fineness mould The river sand of number 2.5~2.6, coarse aggregate use the rubble (maximum particle diameter 20mm) of continuous grading, water to use tap water.Sample dimensions It is 100 × 100 × 400, it is pre-buried in test specimen to wait for Corrosion Reinforcement and stainless steel wire.Reinforcing bar model uses HPB300, protects thickness Degree is 20mm.Reinforcing bar and stainless steel wire diameter are respectively 12mm and 1mm, and the two clear distance is 6mm.At this point, rusty scale central angle is 120°。
Before pouring into a mould concrete, by Fig. 3~Fig. 5 assembly molds.Through-hole bolt 7 is passed through to run through mold, profit stainless steel wire 3 One end of stainless steel wire 3 is fixed with the puller bolt 11 on through-hole bolt 7, other end steel wire sequentially passes through the upper and lower of forcing unit Fulcrum preformed hole is fixed the other end of stainless steel wire 3 using the second puller bolt 17 at upper fulcrum 15, makes mold, stainless steel Silk and forcing unit form a self-balancing system, and the rotation of rotation urging unit loads 16 tensioning stainless steel wire 3 of screw rod, stainless Steel wire 3 tightens the first puller bolt 11 on the through-hole bolt 7 of mold forcing unit side after being tensioned, to fix stainless steel wire 3 prevent from bouncing back.Forcing unit is removed after cutting extra stainless steel wire, finally penetrates reinforcing bar 2.
Casting concrete in a mold, form removal after 1 day age.First loosen on two side through hole bolt 7 of mold before form removal Concrete sample after form removal is invaded bubble in a concentration of 3.5% brine by one puller bolt 11 to loosen stainless steel wire 3, After conserving 28d in fog room, test block is taken out, its surface moisture content is dried.
Towards protective layer side, the foil gauge that length is 50mm is pasted along test block length direction, totally 8.Foil gauge with Deformeter is connected, and deformeter data acquiring frequency is 2 times/min, and to detect in energization tarnishing processes, concrete cover is No cracking.The target corrosion ratio of reinforcing bar is set as 1%.
Stainless steel wire 3 is connect with 4 cathode of constant voltage dc source, will wait for Corrosion Reinforcement 2 with voltage stabilization and current stabilization DC power supply 4 just Pole connects, and opens voltage stabilization and current stabilization DC power supply and is powered, sets electrical current I sizes as 0.03A.Conduction time is calculated according to formula For:
After reaching estimated conduction time, power supply is closed.
Armored concrete test specimen is cut along perpendicular to reinforcing bar length direction, is cut into the sheet test specimen of thickness 10mm.Using The backscattering technique of environmental scanning electron microscope measures the rusty scale thickness distribution along reinforcing bar circumferencial direction.Justified with steel area The heart and the angle in protective layer minimum thickness direction position 0 degree, then rusty scale thickness is as shown in figure 11 along the test result of angular distribution. From in figure it can be found that reinforcing bar (simulate cover to reinforcement minimum at) rusty scale thickness at face stainless steel wire is maximum.With angle Degree increases, and rusty scale thickness is gradually reduced, and backwards to protective layer side, reinforcing bar hardly corrosion meets with natural rust situation.
When specific implementation, the present invention is not limited specific device model, to concrete sample size, reinforcing bar and stainless Steel wire diameter and the two clear distance are not limited, as long as the loading device and concrete sample of above-mentioned function can be completed.
Content described in this specification embodiment is only enumerating to the way of realization of inventive concept, protection of the invention Range is not construed as being only limitted to the concrete form that embodiment is stated, protection scope of the present invention also includes art technology Personnel according to present inventive concept it is conceivable that equivalent technologies mean.

Claims (7)

1. the test method of reinforcing bar nature non-uniform corrosion, includes the following steps in simulation concrete:
1) preparation of mold:By stainless steel wire through mold side and locking, and make the both ends of stainless steel wire fall mold it Outside, after the rate of tension and length of adjusting stainless steel wire, it will wait for the reinforcing bar of corrosion in mold;The stainless steel wire root Determine whether its surface is arranged insulating layer according to test objective;
2) concrete sample is prepared:Casting concrete in a mold, form removal after 1 day age, then arrives concrete sample maintenance Plan age;Wherein first loosen stainless steel wire before form removal;
3) constant current energization corrosion:According to expected corrosion ratio or rusty scale thickness distribution, sets electrical current and calculate conduction time; Stainless steel wire one end is connect with voltage stabilization and current stabilization DC power cathode, will wait for that Corrosion Reinforcement connects with voltage stabilization and current stabilization DC power anode It connects, opens voltage stabilization and current stabilization DC power supply and be powered, set electrical current size, record electrical current and conduction time carries out energization rust Erosion after reaching estimated conduction time, closes power supply;
4) reinforcing bar rusty scale thickness is calculated according to formula (1):Relationship between rusty scale thickness and current density, conduction time and angle Formula:
In formula, TrFor rusty scale spreading depth, unit mm;I is corrosion electric current density, unit A/mm2;R is reinforcing bar radius, single Position is mm;T is conduction time, unit s;θ is angle;When reinforcing bar radius r determinations, as long as effectively control corrosion rate current density i With conduction time t, reinforcing bar can be made to reach expected corrosion ratio, and can predict rust of the rusty scale of non-uniform Distribution at angle, θ Layer thickness Tr
2. the test method of reinforcing bar nature non-uniform corrosion in simulation concrete as described in claim 1, it is characterised in that:Step Rapid 3 conduction time calculates according to formula (2):
In formula, t is conduction time, unit s;ZFeFor the chemical valence of iron, 2 are taken;F is Faraday constant, unit C/mol;MFe For the atomic weight of iron, 56g/mol is taken;I is added size of current, unit A;A0It is accumulated for reinforcing bar original section, unit mm2;L For steel bar corrosion segment length, unit mm;γsFor reinforcing bar density, 7.85 × 10 are taken-3g/mm3;ρ is average corrosion rate.
3. the experiment dress of the test method structure of reinforcing bar nature non-uniform corrosion in simulation concrete as claimed in claim 2 It sets, it is characterised in that:Including die unit, forcing unit, test specimen to be measured and energization unit, the test specimen to be measured is mounted in described Die unit mold in, embedded reinforcement and stainless steel wire inside the test specimen to be measured, the forcing unit, which is stuck in, to be waited for On the stainless steel wire of test block;The reinforcing bar of the anode and test specimen to be measured of the energization unit is electrically connected, the energization unit The stainless steel wire of cathode and test specimen to be measured is electrically connected;
The die unit includes the mold and through-hole bolt for pouring test specimen to be measured, and symmetrical two sides of mold are continued to employ in advance In through reinforcing bar the first hole and for the second hole through stainless steel wire;The through-hole bolt and second hole Hole is spirally connected, and the connection of exocoel in mold is realized in being axially arranged with for the perforative through-hole of stainless steel wire for the through-hole bolt;Institute The through-hole bolt head stated is equipped with the first puller bolt for preventing stainless steel wire from bouncing back;
The forcing unit includes holder and load screw rod, and the holder includes first connecting rod, second connecting rod, and described first The front end of connecting rod is equipped with the upper fulcrum for being stuck on stainless steel wire, the end of the first connecting rod and the second connecting rod It is hinged;The front end of the second connecting rod is equipped with the lower fulcrum for being stuck on stainless steel wire, the end of the second connecting rod And the first connecting rod is spirally connected to form triangle geometry with load screw rod respectively, passes through the described load screw rod adjustment the Corner dimension between one connecting rod and second connecting rod;
The test specimen to be measured includes concrete substrate, reinforcing bar and stainless steel wire, and the reinforcing bar is parallel with stainless steel wire to be embedded in Inside concrete substrate;
The energization unit uses voltage stabilization and current stabilization DC power supply, and the reinforcing bar of the anode and test specimen to be measured of DC power supply is electrically connected, The cathode of DC power supply and the stainless steel wire of test specimen to be measured are electrically connected.
4. the experimental rig of reinforcing bar nature non-uniform corrosion in simulation concrete as claimed in claim 3, it is characterised in that:Institute It includes bed die and rectangle side form to state mold, and the side form is surrounded by two panels L-type steel plate, and two panels L-type steel plate head and the tail pass through fixation Bolt is affixed;And the L-type steel plate of the side form is fixed on by fastening bolt on bed die.
5. the experimental rig of reinforcing bar nature non-uniform corrosion in simulation concrete as claimed in claim 3, it is characterised in that:Institute It is respectively provided with for the preformed hole across stainless steel wire on the upper fulcrum and the lower fulcrum stated, wherein at the preformed hole of upper fulcrum With the second puller bolt for being useful for fixed stainless steel wire.
6. the experimental rig of reinforcing bar nature non-uniform corrosion in simulation concrete as claimed in claim 3, it is characterised in that:Institute It is honeycombed cement sill to state test specimen to be measured, waits for that the reinforcing bar of corrosion and stainless steel wire have different-diameter and sectional area ratio, according to Test objective determines whether stainless steel wire surface is arranged insulating layer, to realize along reinforcing bar length or along reinforcing bar length and circumferencial direction Non-uniform corrosion, and by determining the clear distance of reinforcing bar and stainless steel wire to realize the corrosion area size of reinforcing bar circumferencial direction.
7. the experimental rig of reinforcing bar nature non-uniform corrosion in simulation concrete as claimed in claim 3, it is characterised in that:Institute It states energization unit and indoor 220V alternating currents is converted into voltage stabilization and current stabilization DC power supply, 0~30V of control DC voltage.
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