CN105738273A - Test method and test device for simulating natural inhomogeneous rusting of reinforcing steel bar in concrete - Google Patents
Test method and test device for simulating natural inhomogeneous rusting of reinforcing steel bar in concrete Download PDFInfo
- Publication number
- CN105738273A CN105738273A CN201610129924.0A CN201610129924A CN105738273A CN 105738273 A CN105738273 A CN 105738273A CN 201610129924 A CN201610129924 A CN 201610129924A CN 105738273 A CN105738273 A CN 105738273A
- Authority
- CN
- China
- Prior art keywords
- reinforcing bar
- stainless steel
- corrosion
- steel silk
- concrete
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N17/00—Investigating resistance of materials to the weather, to corrosion, or to light
- G01N17/006—Investigating resistance of materials to the weather, to corrosion, or to light of metals
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N17/00—Investigating resistance of materials to the weather, to corrosion, or to light
- G01N17/02—Electrochemical measuring systems for weathering, corrosion or corrosion-protection measurement
Abstract
The invention discloses a test method and a test device for simulating natural inhomogeneous rusting of a reinforcing steel bar in concrete. The method comprises the following steps: pre-burying stainless steel wires in concrete, and supplying constant-current power for electrolytic reaction to a concrete test piece. The test device comprises a mold unit, a stressing unit, a test piece to be tested and a power supply unit, wherein the mold unit comprises a mold for casting the test piece to be tested, a through hole bolt and a fastening bolt; the stressing unit comprises a bracket, a lower fulcrum, an upper fulcrum, a loading screw rod and a popping bolt; the test piece to be tested comprises a concrete base body, a reinforcing steel bar and a stainless steel wire electrode; the power supply unit adopts a voltage-stabilizing current-stabilizing direct-current power supply. The test method and the test device have the benefits that the test period is short, natural inhomogeneous rusting of the reinforcing steel bar can be effectively simulated, the position, the rusting range and the rusting degree of inhomogeneous rusting in the circumference direction, and inhomogeneous rusting in the length direction of the reinforcing steel bar can be effectively controlled, energy loss caused by concrete resistance can be reduced, and the prediction result precision is high.
Description
Technical field
The present invention relates to the test method of reinforcing bar nature non-uniform corrosion in a kind of simulation concrete and assay device.
Background technology
Due to xoncrete structure drawing materials, cost, advantage in maintenance, in civil engineering, occupy leading position always, have 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).Being in the xoncrete structure under marine environment and deicer salts environmental condition, reinforcement corrosion is the principal element affecting concrete structure durability.The economic loss brought by concrete structure durability, no matter to developed country or developing country, all brings huge economic loss, has caused extensive concern both domestic and external.Cause the concrete cover rust research split of distending for steel bar corrosion, emerge substantial amounts of achievement.Experimental study is the supplementary means that theoretical research is deep, and experimental technique determines the accuracy of experimental study.
Concrete can be produced splitting stresses by steel bar corrosion, thus causes concrete cracking thus reducing the military service performance of xoncrete structure.The impact that concrete rust distending is split by the different reinforcing bar of research, concrete and corrosion degree is significant.Becoming rusty for xoncrete structure the research of swollen dehiscence process, currently used test method mainly has: natural rust method, artificial environment accelerating corrosion method and based on electrochemical energising accelerating corrosion method.
Natural rust method typically requires sets up natural erosion exposure station in marine environment, reinforced concrete member or reduced scale structural model are placed in natural erosion environment, at different time, Rust of Rebar in Concrete situation is detected or detects, thus gathering the proficiency data of steel bar corrosion under natural conditions.But, the projected life of reinforced concrete structure is even go up a century decades under normal circumstances, will study the steel bar corrosion problem of the whole life cycle of xoncrete structure, it is necessary to the joint efforts of several generations, it is clear that can not meet the demand improving method for designing.Therefore, employing strength grade is relatively low concrete material or reduction thickness of concrete cover widely adopt with the method accelerating steel bar corrosion speed.Natural rust method is adopted to there is a lot of difficulty, it is difficult to obtain systematic research achievement in a short time.
Environmental condition is to affect the key factor of etching medium transmission and steel bar corrosion speed in concrete.In order to improve the deficiency of natural rust method, increase the feasibility of test, by the transmission of accelerated erosion medium in test chamber of artificial climate Environmental Law, to reach to shorten the purpose of steel bar corrosion time, and then set up the relation of artificial acceleration corrosion and natural rust.The method still is based on the mechanism of natural rust, and the accelerated erosion method adopted mainly has: improve the concentration of etching medium, ambient temperature and the saturation etc. by salt mist environment or drying and watering cycle improvement of environment inside concrete.By the acquired data of artificial climate Environmental Law to setting up the method for the prediction of xoncrete structure service life or model has good reference value, test period is generally the time of some months to several years, test period is still longer, and manual simulation environmental test chamber cost is higher, still extensively the carrying out of limit assay research.
Visible, according to steel bar corrosion development the natural law, the test method based on natural rust can only accelerate steel bar corrosion speed within the specific limits, shortens research cycle.Electrochemical electrolysis principle is applied to acceleration Rust of Rebar in Concrete test, sets up based on electrochemical energising accelerating corrosion method, be greatly shortened the effective way of test period beyond doubt.Energising accelerating corrosion method is will to treat in concrete that Corrosion Reinforcement is as anode, negative electrode is made with rustless steel or copper sheet, porosity features in conjunction with concrete material, with the hole solution in concrete for medium, by controlling current intensity and conduction time, according to Faraday's law, the target corrosion amount of manual control reinforcing bar.Due to current flow method, to have Speed of steel Corrosion fast, it is easy to the advantage controlling extent of steel corrosion, is therefore widely used in steel bar corrosion is tested.But; according to electrochemical principle; reinforced concrete member is placed in saline solution and carries out energising accelerating corrosion; reinforcing bar can be made to produce uniform corrosion, this with natural conditions under first semi-moon shaped corrosion occur towards concrete cover and cause not being inconsistent by the fact that protective layer one side concrete cracking.Obviously, reinforced concrete structure durability prediction can not be effectively used for based on the achievement in research of this test method.
So-called non-uniform corrosion, is primarily present two kinds of situations: armored concrete, in order to study the swollen dehiscence process of concrete rust, is generally cut into slices, studied as plane strain problems by (1).When natural rust, etching medium arrival rebar surface causes removing blunt of reinforcing steel bar, steel bar corrosion speed to be then by oxygen transmission control.When concrete rust distending splits, the reinforcing bar towards protective layer only has a small amount of corrosion.That is, under natural conditions, reinforcing bar non-uniform corrosion is to there is non-uniform corrosion along reinforcing bar circumferencial direction；(2) concrete is a kind of porous heterogeneous material.Therefore, on reinforcing bar length direction, the corrosion ratio in each corrosion cross section is stochastic variable, and corrosion degree size depends on concrete porosity size.Non-uniform corrosion is there is along reinforcing bar length direction.Study the non-uniform corrosion along reinforcing bar length direction, contribute to the data of the statistics random corrosion of reinforcing bar, for structural bearing capacity forecast analysis.
Chinese patent application publication No. CN101762453A, Shen Qing Publication day are on June 30th, 2010, name is called " in built-in electrode simulation concrete the accelerated test method of reinforcing bar non-uniform corrosion ", Chinese patent Authorization Notice No. CN101782500B, authorized announcement date is on November 2nd, 2011, name is called " in external electrode simulation concrete the accelerated test method of reinforcing bar non-uniform corrosion ", all utilizes electric osmosis principle to make reinforcing bar accelerate to produce non-uniform corrosion in two pieces patent application.Although the method can realize the non-uniform corrosion of reinforcing bar to a certain extent; but reinforcing bar can not be made to produce the non-uniform corrosion along reinforcing bar circumferencial direction and the non-uniform corrosion along reinforcing bar length; and rust can not be made to result from towards concrete cover side, it is impossible to true reflection natural rust transmits, due to chloride ion, oxygen and moisture, the corrosion form caused to rebar surface.And according to electrochemical theory, the distance between electrode and reinforcing bar is more remote, and concrete resistance is more big, thus producing bigger heat effect, cause that predicting the outcome of commonly used Faraday's law prediction steel bar corrosion amount is inaccurate.
Visible, find that a kind of test period is short, cost is low, can the effective accelerating corrosion method of reinforced concrete non-uniform corrosion set up and test device accordingly under simulating natural environment, improve the accuracy adopting Faraday's law prediction corrosion amount, steel bar corrosion causes deepening continuously of xoncrete structure degeneration research most important.
Summary of the invention
It is an object of the invention to overcome the shortcoming of prior art, it is provided that a kind of cycle is short, cost is low, can quickly produce reinforcing bar non-uniform corrosion, can the effectively test method of reinforcing bar nature non-uniform corrosion and assay device in simulation concrete.
The test method of reinforcing bar nature non-uniform corrosion in simulation concrete of the present invention, comprises the following steps:
1) preparation of mould: stainless steel silk is run through mould side and locks, and make the two ends of stainless steel silk drop on outside mould, after adjusting rate of tension and the length of stainless steel silk, the reinforcing bar treating corrosion is mounted in mould；According to test objective, described stainless steel silk determines whether its surface arranges insulating barrier；
2) preparing concrete sample: casting concrete in a mold, form removal after 1 day age, then by concrete sample maintenance to plan age；Wherein first loosen stainless steel silk before form removal；
3) constant current energising corrosion: according to expection corrosion ratio or rusty scale thickness distribution, set electrical current and calculate conduction time；Stainless steel silk one end is connected with constant voltage dc source negative pole, to treat that Corrosion Reinforcement is connected with voltage stabilization and current stabilization DC power anode, open the energising of voltage stabilization and current stabilization DC source, set electrical current size, record electrical current and carry out energising corrosion conduction time, reach to estimate after conduction time, close power supply；
4) reinforcing bar rusty scale thickness is calculated according to formula (1): the relational expression between rusty scale thickness and electric current density, conduction time and angle:
In formula, TrFor rusty scale spreading depth (mm)；I is corrosion electric current density (A/mm2)；R is reinforcing bar radius (mm)；T is conduction time (s)；θ is angle；When reinforcing bar radius is determined, if effectively control corrosion rate electric current density i and conduction time t, reinforcing bar just can be made to reach expection corrosion ratio, and the rusty scale rusty scale thickness T at angle, θ place of non-uniform Distribution can be predictedr。
The assay device that in simulation concrete as described in the present invention, the test method of reinforcing bar nature non-uniform corrosion builds, it is characterized in that: include die unit, forcing unit, test specimen to be measured and energising unit, described test specimen to be measured is contained in the mould of described die unit, the internal embedded reinforcement of described test specimen to be measured and stainless steel silk, described forcing unit is stuck on the stainless steel silk of test specimen to be measured；The described positive pole of energising unit is electrically connected with the reinforcing bar of test specimen to be measured, and the described negative pole of energising unit is electrically connected with the stainless steel silk of test specimen to be measured；
Described die unit includes the mould for building test specimen to be measured and through hole bolt, and two sides of mould symmetry remain for running through the first hole of reinforcing bar and for running through the second hole of stainless steel silk in advance；Described through hole bolt and the second described hole are spirally connected, described through hole bolt be axially arranged with the through hole run through for stainless steel silk, it is achieved the connection of exocoel in mould；Described through hole bolt head is provided with the first puller bolt preventing stainless steel silk from bouncing back；
Described forcing unit includes support and loads screw rod, and described support includes first connecting rod, second connecting rod, and the front end of described first connecting rod is provided with the upper fulcrum for being stuck on stainless steel silk, and the end of described first connecting rod is hinged with described second connecting rod；The front end of described second connecting rod is provided with the lower fulcrum for being stuck on stainless steel silk, the end of described second connecting rod and described first connecting rod are spirally connected with loading screw rod respectively and form triangle geometry, adjust corner dimension between first connecting rod and second connecting rod by described loading screw rod；
Described test specimen to be measured includes concrete substrate, reinforcing bar and stainless steel silk, and described reinforcing bar is parallel with stainless steel silk to be embedded in inside concrete substrate；
Described energising unit adopts voltage stabilization and current stabilization DC source, and the reinforcing bar of the positive pole of DC source and test specimen to be measured is electrically connected, and the stainless steel silk of the negative pole of DC source and test specimen to be measured is electrically connected.
Described mould includes bed die and rectangle side form, and described side form is surrounded by two panels L-type steel plate, and two panels L-type steel plate head and the tail are affixed by fixing bolt；And the L-type steel plate of described side form is bolted on bed die by fastening.
Being respectively provided with on described upper fulcrum and described lower fulcrum for the preformed hole through stainless steel silk, the preformed hole place wherein going up fulcrum is furnished with the second puller bolt for fixing stainless steel silk.
Described test block to be measured is honeycombed cement sill, treat that reinforcing bar and the stainless steel silk of corrosion have different-diameter and sectional area ratio, determine whether stainless steel silk surface arranges insulating barrier according to test objective, to realize along reinforcing bar length or along the non-uniform corrosion of reinforcing bar length and circumferencial direction, and it is determined by the clear distance of reinforcing bar and stainless steel silk to realize the corrosion area size of reinforcing bar circumferencial direction.
Indoor 220V alternating current is converted to voltage stabilization and current stabilization DC source by described energising unit, controls DC voltage 0～30V.
The accelerated test method of reinforcing bar nature non-uniform corrosion in simulation concrete of the present invention, the Forecasting Methodology of its operation principle and non-uniform corrosion rusty scale thickness distribution is as follows:
A electrochemical principle
In electrolyzer, anode betatopic generation oxidation reaction, negative electrode obtains electronics generation reduction reaction.Owing to the movement velocity of electronics is more than the response speed of electrode, negative electrode produces electron rich phenomenon.When annode area is far longer than cathode area, if negative electrode is less from anode distance, due to coulomb active force, from negative electrode more close to anode part, electronics is preferentially lost along wire by repulsion effect, and metal ion is preferentially entered hole solution by graviational interaction, and the form of expression is that anode produces uneven corrosion.
In the present invention, treating that Corrosion Reinforcement is as anode, stainless steel silk is as negative electrode.
B constant current principle
Adopt traditional energising corrosion test method; the whole surface area that target corrosion region is reinforcing bar of energising corrosion, and under field conditions (factors), before crack; first reinforcing bar there is semi-moon shaped corrosion on one side towards protective layer, protective layer not corrosion substantially dorsad.According to natural rust form, it is maximum corrosion regional extent that this method thinks that reinforcing bar, in stainless steel silk with its tangential extent, corrosion, tangent line angle first occurs.According to Faraday law, the mass loss Δ w that steel bar corrosion causessIt is represented by:
In formula, MFeFor the atomic weight of ferrum, take 56g/mol；T is conduction time (s)；ZFeFor the quantivalence of ferrum, take 2；F is Faraday constant (C/mol)；I is added size of current (A).
Assuming to happens is that uniform corrosion in reinforcing bar maximum corrosion regional extent, corrosion ratio is ρ, then the mass loss Δ w that steel bar corrosion causessCan be expressed as again:
Vws=A0ρLγs
In formula, A0For the long-pending (mm of reinforcing bar original section2)；ρ is average corrosion rate；L is steel bar corrosion segment length (mm)；γsFor reinforcing bar density, take 7.85 × 10-3g/mm3。
The relation of conduction time and corrosion ratio can be set up:
But testing according to the present invention, rusty scale is skewness in maximum corrosion regional extent.Setting up polar coordinate system, it is assumed that rusty scale thickness maximum central angle is 0, angle is with clockwise for just, it is believed that during concrete cracking, rusty scale is distributed as:
In formula, TrFor rusty scale spreading depth (mm)；a1Nonuniformity coefficient for rusty scale；a2For the rusty scale spreading coefficient along reinforcing bar girth, θ is angle.
By rusty scale distribution formula it can be seen that rusty scale area AsFor:
Wherein, α is the angle of tangent line and stainless steel silk reinforcing bar circle center line connecting.
Before concrete cracking, the outer reinforcing bar not corrosion of angle [-α, α] scope, rusty scale thickness TrIt is 0.Therefore
And As=n ρ A0, n is the rust coefficient of expansion, generally takes 2.26～3.00.
NamelyBy changing unit, final a1=n ρ A0。
According to a2Implication, it is known that a2Relevant to stainless steel silk and the diameter of reinforcing bar ratio, two variablees of distance.
Relation between electrical current and electric 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, during concrete cover incipient crack, rusty scale central angle can reach 120 degree, now has a2=0.444.
Therefore, it can the relational expression being reduced between rusty scale thickness and electric current density, conduction time and angle:
When reinforcing bar radius is determined, if effectively control corrosion rate electric current density i and conduction time t, reinforcing bar just can be made to reach expection corrosion ratio, and the rusty scale rusty scale thickness T at angle, θ place of non-uniform Distribution can be predictedr。
By built-in stainless steel silk electrode, and the diameter controlling stainless steel silk can realize annode area much larger than cathode area, and controls the two poles of the earth distance, it is possible to the reinforcing bar nature non-uniform corrosion in simulating reinforced concrete effectively.By changing the diameter ratio of stainless steel silk and the distance of reinforcing bar, the quantity of stainless steel silk electrode, stainless steel silk and reinforcing bar, it is possible to effectively control the reinforcing bar along the circumferential direction position of uneven corrosion, corrosion scope and corrosion degree.By stainless steel silk being carried out along its length minor insulation process, it is possible to effectively control the uneven corrosion along reinforcing bar length direction；Stainless steel silk is near with the distance treating rust reinforcing bar, the little energy that concrete resistance consumes, it is possible to be greatly improved the degree of accuracy utilizing Faraday law to calculate steel bar corrosion loss quality；Through hole bolt is arranged at die unit two ends, and is provided with puller bolt on through hole bolt, it is possible to fixes effectively, easily and loosens stainless steel silk.Loading unit adopts simple triangle geometry relation, increases the length on Article 3 limit by changing the angle between two limits, thus realizing stainless steel silk stretch-draw, simple in construction.
Concrete, the using method of the assay device of reinforcing bar nature non-uniform corrosion in described simulation concrete, comprise the following steps:
1) preparation of mould: assembly jig, through hole bolt is screwed in the second hole of mould, stainless steel silk passes the axially extending bore of through hole bolt and then runs through mould, utilize the fixing stainless steel silk of the first puller bolt of through hole bolt head, stainless steel silk one end sequentially passes through the upper lower fulcrum preformed hole of forcing unit after passing through hole bolt, and by the fixing locking of second puller bolt at upper fulcrum place, make mould, stainless steel silk and forcing unit one self-balancing system of composition, the rotation of rotation urging unit loads screw stretching stainless steel silk, after stainless steel silk tensioning, the puller bolt on the through hole bolt of mould forcing unit side is tightened, retraction is prevented with fixing stainless steel silk；Remove forcing unit after cutting off unnecessary stainless steel silk, finally penetrate and treat Corrosion Reinforcement；
2) preparation of concrete sample: casting concrete in a mold, form removal after 1 day age；The puller bolt on mould two side through hole bolt is first loosened, thus loosening stainless steel silk, by concrete sample form removal maintenance to plan age before form removal；
3) constant current energising corrosion: according to expection corrosion ratio or rusty scale thickness distribution, set electrical current and calculate conduction time；Stainless steel silk is connected with constant voltage dc source negative pole, will treat that Corrosion Reinforcement is connected with voltage stabilization and current stabilization DC power anode, open the energising of voltage stabilization and current stabilization DC source, set electrical current size, record electrical current and carry out energising corrosion conduction time, reaches to estimate after conduction time, closes power supply.
The present invention can control the reinforcing bar position along the uneven corrosion of circumferential direction by the relative position of change steel wire with reinforcing bar, it is also possible to carries out Axinlly nonuniform corrosion by steel wire carries out the parcel of minor insulation adhesive tape.
Beneficial effects of the present invention is mainly manifested in:
1. by built-in stainless steel silk electrode, and the diameter controlling stainless steel silk can realize annode area much larger than cathode area, and control the two poles of the earth distance, it is possible to the reinforcing bar nature non-uniform corrosion in simulating reinforced concrete effectively, and experimentation cost is low, simple to operate, the test period is short.
2. by changing the diameter ratio of stainless steel silk and the distance of reinforcing bar, the quantity of stainless steel silk electrode, stainless steel silk and reinforcing bar, it is possible to effectively control the reinforcing bar along the circumferential direction position of uneven corrosion, corrosion scope and corrosion degree.
3. by stainless steel silk being carried out along its length minor insulation process, it is possible to effectively control the uneven corrosion along reinforcing bar length direction.
4. stainless steel silk is near with the distance treating rust reinforcing bar, the little energy that concrete resistance consumes, it is possible to be greatly improved the degree of accuracy utilizing Faraday law to calculate steel bar corrosion loss quality.
5. through hole bolt is arranged at die unit two ends, and is provided with puller bolt on through hole bolt, it is possible to fixes effectively, easily and loosens stainless steel silk.
6. loading unit adopts simple triangle geometry relation, increases the length on Article 3 limit by changing the angle between two limits, thus realizing stainless steel silk stretch-draw, simple in construction.
Accompanying drawing explanation
Fig. 1 be the present invention concrete in cell reaction principle schematic (wherein, I represents electric current, and V represents voltage)；
Fig. 2 is that (21 represent corrosion region for the reinforcing bar circumferencial direction uneven corrosion footpath schematic diagram of the present invention；211 represent rusty scale border；212 represent reinforcing bar contour line before corrosion；213 represent corrosion after reinforcing bar contour line wherein, r represents reinforcing bar original radius, and d represents the clear distance between stainless steel silk and reinforcing bar, and α represents the maximum angle of corrosion layer and reinforcing bar center of circle stainless steel silk line)；
Fig. 3 is the mode host visual pattern of the present invention；
Fig. 4 is the mould top view of the present invention；
Fig. 5 is the mould 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 that the rust distribution along the circumferential direction of non-uniform corrosion reinforcing bar is accelerated in energising.
Detailed description of the invention
The present invention is further illustrated below in conjunction with accompanying drawing
With reference to accompanying drawing:
The test method of reinforcing bar nature non-uniform corrosion in embodiment 1 simulation concrete of the present invention, comprises the following steps:
1) preparation of mould: stainless steel silk is run through mould side and locks, and make the two ends of stainless steel silk drop on outside mould, after adjusting rate of tension and the length of stainless steel silk, the reinforcing bar treating corrosion is mounted in mould；According to test objective, described stainless steel silk determines whether its surface arranges insulating barrier；
2) preparing concrete sample: casting concrete in a mold, form removal after 1 day age, then by concrete sample maintenance to plan age；Wherein first loosen stainless steel silk before form removal；
3) constant current energising corrosion: according to expection corrosion ratio or rusty scale thickness distribution, set electrical current and calculate conduction time；Stainless steel silk one end is connected with constant voltage dc source negative pole, to treat that Corrosion Reinforcement is connected with voltage stabilization and current stabilization DC power anode, open the energising of voltage stabilization and current stabilization DC source, set electrical current size, record electrical current and carry out energising corrosion conduction time, reach to estimate after conduction time, close power supply；
4) reinforcing bar rusty scale thickness is calculated according to formula (1): the relational expression between rusty scale thickness and electric current density, conduction time and angle:
In formula, TrFor rusty scale spreading depth (mm)；I is corrosion electric current density (A/mm2)；R is reinforcing bar radius (mm)；T is conduction time (s)；θ is angle；When reinforcing bar radius is determined, if effectively control corrosion rate electric current density i and conduction time t, reinforcing bar just can be made to reach expection corrosion ratio, and the rusty scale rusty scale thickness T at angle, θ place of non-uniform Distribution can be predictedr。
The conduction time of step 3 calculates according to formula (2):
In formula, t is conduction time (s)；ZFeFor the quantivalence of ferrum, take 2；F is Faraday constant (C/mol)；MFeFor the atomic weight of ferrum, take 56g/mol；I is added size of current (A)；A0For the long-pending (mm of reinforcing bar original section2)；L is steel bar corrosion segment length (mm)；γsFor reinforcing bar density, take 7.85 × 10-3g/mm3；ρ is average corrosion rate.
The assay device that in embodiment 2 simulation concrete as described in Example 1, the test method of reinforcing bar nature non-uniform corrosion builds, including die unit, forcing unit, test specimen to be measured and energising unit, described test specimen to be measured is contained in the mould of described die unit, the internal embedded reinforcement 2 of described test specimen to be measured and stainless steel silk 3, described forcing unit is stuck on the stainless steel silk of test specimen to be measured；The described positive pole of energising unit is electrically connected with the reinforcing bar of test specimen to be measured, and the described negative pole of energising unit is electrically connected with the negative electrode of test specimen to be measured；
Described die unit includes the mould for building test specimen to be measured and through hole bolt 7, and two sides of mould symmetry remain for running through the first hole 9 of reinforcing bar 2 and for running through the second hole 10 of stainless steel silk 3 in advance；Described through hole bolt 7 and the second described hole 10 are spirally connected, described through hole bolt 7 be axially arranged with the through hole run through for stainless steel silk 3, it is achieved the connection of exocoel in mould；Described through hole bolt 7 head is provided with the first puller bolt 11 preventing stainless steel silk 3 from bouncing back；
Described forcing unit includes support 13 and loads screw rod 16, described support 13 includes first connecting rod, second connecting rod, the front end of described first connecting rod is provided with the upper fulcrum 15 for being stuck on stainless steel silk, and the end of described first connecting rod is hinged with described second connecting rod；The front end of described second connecting rod is provided with the lower fulcrum 14 for being stuck on stainless steel silk, the end of described second connecting rod and described first connecting rod are spirally connected with loading screw rod 16 respectively, adjust corner dimension between first connecting rod and second connecting rod by described loading screw rod 16；
Described test specimen to be measured includes concrete substrate 1, reinforcing bar 2 and stainless steel silk 3, and described reinforcing bar 2 is parallel with stainless steel silk 3 is embedded in concrete substrate 1 inside；
Described energising unit adopts voltage stabilization and current stabilization DC source 4, and the reinforcing bar 2 of the positive pole of DC source 4 and test specimen to be measured is electrically connected, and the stainless steel silk 3 of the negative pole of DC source 4 and test specimen to be measured is electrically connected.
Described mould includes bed die 6 and rectangle side form, and described side form is surrounded by two panels L-type steel plate 5, and two panels L-type steel plate 5 head and the tail are affixed by fixing bolt；And the L-type steel plate 5 of described side form is fixed on bed die 6 by fastening bolt 8.
Being respectively provided with on described upper fulcrum 15 and described lower fulcrum 14 for the preformed hole through stainless steel silk 3, the preformed hole place wherein going up fulcrum 15 is furnished with the second puller bolt 17 for fixing stainless steel silk.
Described test block to be measured is honeycombed cement sill, treat that reinforcing bar and the stainless steel silk of corrosion have different-diameter and sectional area ratio, determine whether stainless steel silk surface arranges insulating barrier according to test objective, to realize along reinforcing bar length or along the non-uniform corrosion of reinforcing bar length and circumferencial direction, and it is determined by the clear distance of reinforcing bar and stainless steel silk to realize the corrosion area size of reinforcing bar circumferencial direction.
Indoor 220V alternating current is converted to voltage stabilization and current stabilization DC source by described energising unit, controls DC voltage 0～30V.
Embodiment 3 is below to measure the ratio of mud 0.53, match ratio for cement: water: sand: the concrete of coarse aggregate=1:0.53:2.0:3.0 is energized corrosion after built-in stainless steel silk, and the work of the present invention is illustrated.
This concrete raw material of embodiment mixing is: cement is P.I52.5 class a portland cement, and sand adopts the fluvial sand of modulus of fineness 2.5～2.6, and coarse aggregate adopts the rubble (maximum particle diameter 20mm) of continuous grading, hydromining tap water.Sample dimensions is 100 × 100 × 400, pre-buried in test specimen treats Corrosion Reinforcement and stainless steel silk.Reinforcing bar model adopts HPB300, and protective layer thickness is 20mm.Reinforcing bar and stainless steel silk diameter respectively 12mm and 1mm, both clear distances are 6mm.Now, rusty scale central angle is 120 °.
Before cast concrete, by Fig. 3～Fig. 5 assembly jig.Stainless steel silk 3 is run through mould through through hole bolt 7, the puller bolt 11 on through hole bolt 7 is utilized to fix one end of stainless steel silk 3, other end steel wire sequentially passes through the upper lower fulcrum preformed hole of forcing unit, in employing, the other end of stainless steel silk 3 fixed by second puller bolt 17 at fulcrum 15 place, make mould, stainless steel silk and forcing unit one self-balancing system of composition, the rotation of rotation urging unit loads screw rod 16 stretch-draw stainless steel silk 3, after stainless steel silk 3 tensioning, the first puller bolt 11 on the through hole bolt 7 of mould forcing unit side is tightened, retraction is prevented with fixing stainless steel silk 3.Remove forcing unit after cutting off unnecessary stainless steel silk, finally penetrate reinforcing bar 2.
Casting concrete in a mold, form removal after 1 day age.First loosen the first puller bolt 11 on mould two side through hole bolt 7 before form removal, thus loosening stainless steel silk 3, the concrete sample after form removal being invaded bubble in the saline that concentration is 3.5%, in fog room after maintenance 28d, taking out test block, drying its surface moisture content.
Towards protective layer side, pasting length along test block length direction is the foil gauge of 50mm, totally 8.Foil gauge is connected with deformeter, and deformeter data acquiring frequency is 2 times/min, and in order to detect in energising tarnishing processes, whether concrete cover ftractures.Set the target corrosion ratio of reinforcing bar as 1%.
Stainless steel silk 3 is connected with constant voltage dc source 4 negative pole, will treat that Corrosion Reinforcement 2 is connected with voltage stabilization and current stabilization DC source 4 positive pole, open the energising of voltage stabilization and current stabilization DC source, set electrical current I and be sized to 0.03A.According to formula calculating it is conduction time:
Reach to estimate after conduction time, close power supply.
Along being perpendicular to reinforcing bar length direction cutting of steel reinforced concrete test specimen, it is cut into the lamellar test specimen of thickness 10mm.Adopt the backscattering technique of environmental scanning electron microscope, measure the rusty scale thickness distribution along reinforcing bar circumferencial direction.Position 0 degree with the angle in the steel area center of circle and protective layer minimum thickness direction, then rusty scale thickness along angular distribution result of the test as shown in figure 11.It is found that reinforcing bar is just maximum to stainless steel silk (i.e. the simulation minimum place of cover to reinforcement) rusty scale thickness from figure.Increasing with angle, rusty scale thickness is gradually reduced, dorsad protective layer side, and reinforcing bar is corrosion hardly, meets with natural rust situation.
When implementing, concrete device model is not limited by the present invention, and concrete sample size, reinforcing bar and stainless steel silk diameter and both clear distances are not limited, as long as charger and the concrete sample of above-mentioned functions can be completed.
Content described in this specification embodiment is only enumerating of the way of realization to inventive concept; protection scope of the present invention is not construed as being only limitted to the concrete form that embodiment is stated, protection scope of the present invention also include those skilled in the art according to present inventive concept it is conceivable that equivalent technologies means.
Claims (7)
1. the test method of reinforcing bar nature non-uniform corrosion in simulation concrete, comprises the following steps:
1) preparation of mould: stainless steel silk is run through mould side and locks, and make the two ends of stainless steel silk drop on outside mould, after adjusting rate of tension and the length of stainless steel silk, the reinforcing bar treating corrosion is mounted in mould；According to test objective, described stainless steel silk determines whether its surface arranges insulating barrier；
2) preparing concrete sample: casting concrete in a mold, form removal after 1 day age, then by concrete sample maintenance to plan age；Wherein first loosen stainless steel silk before form removal；
3) constant current energising corrosion: according to expection corrosion ratio or rusty scale thickness distribution, set electrical current and calculate conduction time；Stainless steel silk one end is connected with constant voltage dc source negative pole, to treat that Corrosion Reinforcement is connected with voltage stabilization and current stabilization DC power anode, open the energising of voltage stabilization and current stabilization DC source, set electrical current size, record electrical current and carry out energising corrosion conduction time, reach to estimate after conduction time, close power supply；
4) reinforcing bar rusty scale thickness is calculated according to formula (1): the relational expression between rusty scale thickness and electric current density, conduction time and angle:
In formula, TrFor rusty scale spreading depth (mm)；I is corrosion electric current density (A/mm2)；R is reinforcing bar radius (mm)；T is conduction time (s)；θ is angle；When reinforcing bar radius r determines, if effectively control corrosion rate electric current density i and conduction time t, reinforcing bar just can be made to reach expection corrosion ratio, and the rusty scale rusty scale thickness T at angle, θ place of non-uniform Distribution can be predictedr。
2. the test method of reinforcing bar nature non-uniform corrosion in simulation concrete as claimed in claim 1, it is characterised in that: the conduction time of step 3 calculates according to formula (2):
In formula, t is conduction time (s)；ZFeFor the quantivalence of ferrum, take 2；F is Faraday constant (C/mol)；MFeFor the atomic weight of ferrum, take 56g/mol；I is added size of current (A)；A0For the long-pending (mm of reinforcing bar original section2)；L is steel bar corrosion segment length (mm)；γsFor reinforcing bar density, take 7.85 × 10-3g/mm3；ρ is average corrosion rate.
3. the assay device that in simulation concrete as claimed in claim 2, the test method of reinforcing bar nature non-uniform corrosion builds, it is characterized in that: include die unit, forcing unit, test specimen to be measured and energising unit, described test specimen to be measured is contained in the mould of described die unit, the internal embedded reinforcement of described test specimen to be measured and stainless steel silk, described forcing unit is stuck on the stainless steel silk of test specimen to be measured；The described positive pole of energising unit is electrically connected with the reinforcing bar of test specimen to be measured, and the described negative pole of energising unit is electrically connected with the stainless steel silk of test specimen to be measured；
Described die unit includes the mould for building test specimen to be measured and through hole bolt, and two sides of mould symmetry remain for running through the first hole of reinforcing bar and for running through the second hole of stainless steel silk in advance；Described through hole bolt and the second described hole are spirally connected, described through hole bolt be axially arranged with the through hole run through for stainless steel silk, it is achieved the connection of exocoel in mould；Described through hole bolt head is provided with the first puller bolt preventing stainless steel silk from bouncing back；
Described forcing unit includes support and loads screw rod, and described support includes first connecting rod, second connecting rod, and the front end of described first connecting rod is provided with the upper fulcrum for being stuck on stainless steel silk, and the end of described first connecting rod is hinged with described second connecting rod；The front end of described second connecting rod is provided with the lower fulcrum for being stuck on stainless steel silk, the end of described second connecting rod and described first connecting rod are spirally connected with loading screw rod respectively and form triangle geometry, adjust corner dimension between first connecting rod and second connecting rod by described loading screw rod；
Described test specimen to be measured includes concrete substrate, reinforcing bar and stainless steel silk, and described reinforcing bar is parallel with stainless steel silk to be embedded in inside concrete substrate；
Described energising unit adopts voltage stabilization and current stabilization DC source, and the reinforcing bar of the positive pole of DC source and test specimen to be measured is electrically connected, and the stainless steel silk of the negative pole of DC source and test specimen to be measured is electrically connected.
4. the assay device of reinforcing bar nature non-uniform corrosion in simulation concrete as claimed in claim 3, it is characterised in that: described mould includes bed die and rectangle side form, and described side form is surrounded by two panels L-type steel plate, and two panels L-type steel plate head and the tail are affixed by fixing bolt；And the L-type steel plate of described side form is bolted on bed die by fastening.
5. the assay device of reinforcing bar nature non-uniform corrosion in simulation concrete as claimed in claim 3, it is characterized in that: being respectively provided with on described upper fulcrum and described lower fulcrum for the preformed hole through stainless steel silk, the preformed hole place wherein going up fulcrum is furnished with the second puller bolt for fixing stainless steel silk.
6. the assay device of reinforcing bar nature non-uniform corrosion in simulation concrete as claimed in claim 3, it is characterized in that: described test block to be measured is honeycombed cement sill, treat that reinforcing bar and the stainless steel silk of corrosion have different-diameter and sectional area ratio, determine whether stainless steel silk surface arranges insulating barrier according to test objective, to realize along reinforcing bar length or along the non-uniform corrosion of reinforcing bar length and circumferencial direction, and it is determined by the clear distance of reinforcing bar and stainless steel silk to realize the corrosion area size of reinforcing bar circumferencial direction.
7. the assay device of reinforcing bar nature non-uniform corrosion in simulation concrete as claimed in claim 3, it is characterised in that: indoor 220V alternating current is converted to voltage stabilization and current stabilization DC source by described energising unit, controls DC voltage 0～30V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610129924.0A CN105738273B (en) | 2016-03-08 | 2016-03-08 | The test method and experimental rig of reinforcing bar nature non-uniform corrosion in simulation concrete |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610129924.0A CN105738273B (en) | 2016-03-08 | 2016-03-08 | The test method and experimental rig of reinforcing bar nature non-uniform corrosion in simulation concrete |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105738273A true CN105738273A (en) | 2016-07-06 |
| CN105738273B CN105738273B (en) | 2018-08-21 |
Family
ID=56249231
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610129924.0A Active CN105738273B (en) | 2016-03-08 | 2016-03-08 | The test method and experimental rig of reinforcing bar nature non-uniform corrosion in simulation concrete |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105738273B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106053327A (en) * | 2016-07-27 | 2016-10-26 | 湖北省交通运输厅黄黄高速公路管理处 | Electrochemical monitoring method of rebar corrosion degree in reinforced concrete |
| CN106932338A (en) * | 2017-04-11 | 2017-07-07 | 青岛理工大学 | Extravasation electricity accelerates steel bar corrosion test device and building method |
| CN108562534A (en) * | 2017-12-29 | 2018-09-21 | 浙江大学 | A kind of reinforcing bar non-uniform corrosion auxiliary electrode positioning device |
| CN108645780A (en) * | 2018-05-15 | 2018-10-12 | 江苏建筑职业技术学院 | The test method of reinforcing bar accelerating corrosion in a kind of reinforced concrete foundation |
| CN109655398A (en) * | 2019-02-27 | 2019-04-19 | 长安大学 | A kind of device and measurement method for the corrosion of testing conductive concrete steel bridge panel |
| CN110823983A (en) * | 2019-10-08 | 2020-02-21 | 九州职业技术学院 | Real-time monitoring device and detection method for reinforced bar galvanic couples in concrete |
| CN113008976A (en) * | 2021-03-30 | 2021-06-22 | 浙江工业大学 | Steel bar corrosion device suitable for three magnetic sensors and calibration method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20070027167A (en) * | 2005-09-06 | 2007-03-09 | 민선영 | Structure and Method of Inspection for Corrosion Testing of Reinforced Concrete Structures in Bridges and Buildings |
| JP2011033596A (en) * | 2009-08-06 | 2011-02-17 | Sumitomo Electric Ind Ltd | Corrosion testing method |
| CN102095677A (en) * | 2010-12-01 | 2011-06-15 | 浙江大学 | Method for monitoring corrosion cracks of reinforced concrete and sensor |
| CN102721642A (en) * | 2012-07-13 | 2012-10-10 | 中南大学 | Sensor device for long-term monitoring of reinforcement corrosion conditions and applied inside concrete |
| CN202533356U (en) * | 2012-04-28 | 2012-11-14 | 中交四航工程研究院有限公司 | Concrete structure durability real-time monitoring sensor |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN205719896U (en) * | 2016-03-08 | 2016-11-23 | 浙江工业大学 | The assay device of reinforcing bar nature non-uniform corrosion in simulation concrete |
-
2016
- 2016-03-08 CN CN201610129924.0A patent/CN105738273B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20070027167A (en) * | 2005-09-06 | 2007-03-09 | 민선영 | Structure and Method of Inspection for Corrosion Testing of Reinforced Concrete Structures in Bridges and Buildings |
| JP2011033596A (en) * | 2009-08-06 | 2011-02-17 | Sumitomo Electric Ind Ltd | Corrosion testing method |
| CN102095677A (en) * | 2010-12-01 | 2011-06-15 | 浙江大学 | Method for monitoring corrosion cracks of reinforced concrete and sensor |
| CN202533356U (en) * | 2012-04-28 | 2012-11-14 | 中交四航工程研究院有限公司 | Concrete structure durability real-time monitoring sensor |
| CN102721642A (en) * | 2012-07-13 | 2012-10-10 | 中南大学 | Sensor device for long-term monitoring of reinforcement corrosion conditions and applied inside concrete |
Non-Patent Citations (2)
| Title |
|---|
| MASARU YOKOTA等: "Environmental Influence on the Corrosion Rate of Steel Bars Embedded in Concrete", 《ISIJ INTERNATIONAL》 * |
| 艾志勇等: "低合金耐蚀钢筋锈蚀研究现状及存在的问题分析", 《腐蚀科学与防护技术》 * |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106053327A (en) * | 2016-07-27 | 2016-10-26 | 湖北省交通运输厅黄黄高速公路管理处 | Electrochemical monitoring method of rebar corrosion degree in reinforced concrete |
| CN106932338A (en) * | 2017-04-11 | 2017-07-07 | 青岛理工大学 | Extravasation electricity accelerates steel bar corrosion test device and building method |
| CN106932338B (en) * | 2017-04-11 | 2023-12-29 | 青岛理工大学 | Extravasation electric acceleration steel bar corrosion testing device and construction method |
| CN108562534A (en) * | 2017-12-29 | 2018-09-21 | 浙江大学 | A kind of reinforcing bar non-uniform corrosion auxiliary electrode positioning device |
| CN108562534B (en) * | 2017-12-29 | 2023-09-05 | 浙江大学 | Reinforcing bar non-uniform corrosion auxiliary electrode positioner |
| CN108645780A (en) * | 2018-05-15 | 2018-10-12 | 江苏建筑职业技术学院 | The test method of reinforcing bar accelerating corrosion in a kind of reinforced concrete foundation |
| CN108645780B (en) * | 2018-05-15 | 2020-11-03 | 江苏建筑职业技术学院 | Test method for accelerated corrosion of steel bar in reinforced concrete foundation |
| CN109655398A (en) * | 2019-02-27 | 2019-04-19 | 长安大学 | A kind of device and measurement method for the corrosion of testing conductive concrete steel bridge panel |
| CN109655398B (en) * | 2019-02-27 | 2023-11-10 | 长安大学 | Device for testing corrosion of conductive concrete steel bridge deck and measuring method |
| CN110823983A (en) * | 2019-10-08 | 2020-02-21 | 九州职业技术学院 | Real-time monitoring device and detection method for reinforced bar galvanic couples in concrete |
| CN113008976A (en) * | 2021-03-30 | 2021-06-22 | 浙江工业大学 | Steel bar corrosion device suitable for three magnetic sensors and calibration method |
| CN113008976B (en) * | 2021-03-30 | 2024-04-16 | 浙江工业大学 | Reinforcing steel bar corrosion calibration device and method suitable for three magnetic sensors |
Also Published As
| Publication number | Publication date |
|---|---|
| CN105738273B (en) | 2018-08-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105738273A (en) | Test method and test device for simulating natural inhomogeneous rusting of reinforcing steel bar in concrete | |
| Sassani et al. | Carbon fiber-based electrically conductive concrete for salt-free deicing of pavements | |
| CN101620062B (en) | Method for testing control of accelerating corrosion of steel reinforcement in chlorine salt corrosion concrete | |
| Castellote et al. | Accelerated simultaneous determination of the chloride depassivation threshold and of the non-stationary diffusion coefficient values | |
| CN102621049B (en) | Concrete chloride ion migration coefficient load testing device under bending stress, and testing method thereof | |
| CN104964920B (en) | A kind of device and method of simulating reinforced concrete natural rust | |
| Nygaard et al. | A method for measuring the chloride threshold level required to initiate reinforcement corrosion in concrete | |
| Wang et al. | Semi-empirical prediction model of chloride-induced corrosion rate in uncracked reinforced concrete exposed to a marine environment | |
| Jäggi et al. | Macrocell corrosion of steel in concrete–experiments and numerical modelling | |
| CN205719896U (en) | The assay device of reinforcing bar nature non-uniform corrosion in simulation concrete | |
| Fang et al. | Investigation of electrochemical chloride removal from concrete using direct and pulse current | |
| Wang et al. | Effect of colloid solution concentration of epoxy resin on properties of rust-cracked reinforced concrete repaired by electrophoretic deposition | |
| Yin et al. | Corrosion characteristics of anchor cables in electrolytic corrosion test and the applicability of the test method in study of anchor cable corrosion | |
| CN108169114B (en) | Self-locking tensioning device for reinforcing steel bar non-uniform corrosion auxiliary electrode limiter | |
| CN204718941U (en) | A kind of device of simulating reinforced concrete natural rust | |
| Sadrinejad et al. | Influence of hybrid fibers on serviceability of RC beams under loading and steel corrosion | |
| Radhi et al. | Relationship between steel mass loss and accelerated corrosion regimes in reinforced concrete columns | |
| CN207937326U (en) | Reinforcing bar non-uniform corrosion auxiliary electrode limiter self-locking tensioning apparatus | |
| Jang et al. | Rebar corrosion under simulated concrete conditions using galvanic current measurements | |
| En-Hou et al. | Chemical and electrochemical conditions within corrosion fatigue cracks | |
| CN103376281B (en) | Device and method for determining solidified soil chloride ion diffusion coefficient | |
| CN108562534B (en) | Reinforcing bar non-uniform corrosion auxiliary electrode positioner | |
| Torres-Acosta | Accelerated vs. natural corrosion experimental results for remaining life stage forecasting | |
| CN207751849U (en) | A kind of reinforcing bar non-uniform corrosion auxiliary electrode positioning device | |
| Zhou et al. | AE Monitoring Corrosion-induced Deterioration of Reinforced Concrete Piles in The Simulated Marine Environment |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |