CN106637232B - A kind of improved method of electrochemistry extraction Chloride Ion in Concrete - Google Patents

A kind of improved method of electrochemistry extraction Chloride Ion in Concrete Download PDF

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CN106637232B
CN106637232B CN201611126710.4A CN201611126710A CN106637232B CN 106637232 B CN106637232 B CN 106637232B CN 201611126710 A CN201611126710 A CN 201611126710A CN 106637232 B CN106637232 B CN 106637232B
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concrete
cement
carbon cloth
magnesium phosphate
test specimen
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CN106637232A (en
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李悦
林辉
赵畅
谢梦洋
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Beijing University of Technology
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
    • C23F13/02—Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
    • C23F13/06—Constructional parts, or assemblies of cathodic-protection apparatus
    • C23F13/08—Electrodes specially adapted for inhibiting corrosion by cathodic protection; Manufacture thereof; Conducting electric current thereto
    • C23F13/16—Electrodes characterised by the combination of the structure and the material
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
    • C23F13/02—Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
    • C23F13/06—Constructional parts, or assemblies of cathodic-protection apparatus
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
    • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
    • E04B1/64—Insulation or other protection; Elements or use of specified material therefor for making damp-proof; Protection against corrosion
    • E04B1/642—Protecting metallic construction elements against corrosion
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G23/00—Working measures on existing buildings
    • E04G23/02—Repairing, e.g. filling cracks; Restoring; Altering; Enlarging
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F2201/00—Type of materials to be protected by cathodic protection
    • C23F2201/02—Concrete, e.g. reinforced
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F2213/00—Aspects of inhibiting corrosion of metals by anodic or cathodic protection
    • C23F2213/20—Constructional parts or assemblies of the anodic or cathodic protection apparatus
    • C23F2213/22—Constructional parts or assemblies of the anodic or cathodic protection apparatus characterized by the ionic conductor, e.g. humectant, hydratant or backfill

Abstract

A kind of improved method of electrochemistry extraction Chloride Ion in Concrete, is related to lossless repairing and reinforcing field.The molar ratio M/P of wherein (1) MgO (M) and phosphate (P) is 4~5；(2) retarder volume is 5~10wt% of magnesia quality；(3) water-cement ratio：0.14~0.16；(4) conductive material volume is the 0.01%~0.05% of magnesia quality；(5) electrolyte quality percent concentration：10%~15%；(6) carbon cloth：Tensile strength >=2500MPa, every meter of resistance：35~40 Ω/m.The present invention improves magnesium phosphate cement electric conductivity by carbon nanotube, carbon cloth, which is bonded, with it obtains external anode material, using with the modified nanometer calcium silicates of cetyl trimethylammonium bromide as electrolyte, external direct current power supply repairs concrete inner structure while dechlorinating and reinforcing.This method makes the electrochemical dechlorination efficiency of concrete significantly improve, and effectively reduces the loss of cohesive force between steel-concrete.

Description

A kind of improved method of electrochemistry extraction Chloride Ion in Concrete
Technical field
The present invention relates to a kind of improved methods of armored concrete electrochemical dechlorination, belong to armored concrete electrochemistry neck Domain can be used for the lossless repairing and reinforcing of structural concrete.
Background technology
Armored concrete is because its good structural behaviour and durability are widely used in civil engineering, but in reinforced concrete During soil structure is on active service, steel bar corrosion is the most common destruction shape of current concrete structure caused by external environment corrodes Formula.But from the point of view of the failure mode of most of armored concrete, steel bar corrosion caused by chloride erosion is to destroy armored concrete The main arch-criminal of structure.Currently, electrochemical desalting is the major way of reinforced concrete structure dechlorination, under the action of electric field, Using reinforcement in concrete as cathode, closed circuit is formed by additional anode.Positively charged ion is to reinforcing bar in armored concrete Near zone moves, and electronegative Cl-To anode direction migration is added outside under the driving of electric field, reach dechlorination effect.
In existing dechlorination technology, common external anode material has ordinary steel silk screen, titanium net and cement based conductive layer, often The electrolyte seen has a Ca (OH), LiOH, NaOH and contains cationic corrosion inhibitor or Na2B4O7·10H2The saturation aqueous slkali of O. But there are certain drawbacks during dechlorination for above-mentioned dechlorination device：It is easy corrosion during the dechlorination of ordinary steel silk screen, dechlorinate effect It is bad；Titanium net is expensive, and large area is laid with difficult；Cement and conductive layer are suitble to big vertical plane structure, application range limited.Together When, dechlorination adversely affects armored concrete performance, and electrolyte used is poor to concrete inner structure repair efficiency.Therefore, It proposes and external anode is made with the cementing carbon cloth of magnesium phosphate cement, realize the dechlorination and reinforcing of concrete structure, select and be modified Nanometer calcium silicates is electrolyte, the new method repaired to inside concrete while dechlorination.This method can dechlorinate While realize concrete structure reinforcing, simplify the process for the post-reinforcing that first dechlorinates in conventional method, nanometer calcium silicates draws Enter the aquation for promoting unreacting particle in concrete, play the role of certain repairing, being that armored concrete is lossless repairs and add The application of solid method lays the foundation.
Invention content
The present invention solves the technical problem of：The improvement for the conventional method that dechlorinates for concrete realizes that dechlorination is reinforced Integration improves the problem that armored concrete performance loss is serious after dechlorinating.Therefore, it discloses a kind of cementing with magnesium phosphate cement Carbon cloth makees external anode, using modified Nano calcium silicates as electrolyte, extracts the new method of Chloride Ion in Concrete.
The technical characteristic of the present invention：It is modified by the magnesium phosphate cement to poorly conductive, carbon cloth is bonded with it Obtain external anode material, using modified Nano calcium silicates as electrolyte, dechlorinate reinforce while to concrete inner structure into Row repairing.The material mixture ratio and parameter are as follows：
(1) the molar ratio M/P of MgO (M) and phosphate (P)：4~5；
(2) retarder volume：It is 5~10wt% of magnesia quality；
(3) water-cement ratio：0.14~0.16；
(4) conductive material volume：It is the 0.01%~0.05% of magnesia quality；
(5) electrolyte quality percent concentration：10%~15%；
(6) carbon cloth：Tensile strength >=2500MPa, every meter of resistance：35~40 Ω/m.
The magnesium phosphate cement is 1600 DEG C of grain magnesites；The calcination temperature of dead roasting MgO at 1600 DEG C or more,
The phosphate is PHOSPHORIC ACID TECH.GRADE potassium dihydrogen；
The retarder is borax；
The conductive material is carbon nanotube；
The electrolyte is the nanometer silicic acid calcium solution being modified using cetyl trimethylammonium bromide.Concrete operations For：It is 1 by mass ratio:4 cetyl trimethylammonium bromide is uniformly mixed with nanometer calcium silicates, thin in BILON-1000Y types Born of the same parents, which are crushed in instrument, to be disperseed, and it is 22 ± 1KHz, jitter time 5min to be crushed instrument frequency, obtains the electrolysis of modified Nano calcium silicates Liquid, it is 50.32mV to measure its Zeta potential, and particle diameter distribution is in 50~100nm.
A kind of method of electrochemistry extraction Chloride Ion in Concrete, which is characterized in that the cementitious carbon fiber of modified phosphate magnesium Wei Bu makees concrete electrochemical dechlorination external anode, and concrete component chlorion is realized in modified Nano calcium silicates electrolyte Extraction, implementation steps are as follows：
1. the processing of concrete surface：It will conserve to the concrete of 28d and take out, and to its surface be polishing to smooth, general It is placed in the center of the pvc pipe bigger than its diameter；
2. prepared by modified phosphate magnesium cement：Phosphate, retarder and conductive material are uniformly mixed, water is added to stir 5min, Dead MgO is then added, stirs evenly, water-cement ratio is 0.14~0.16；
3. the preparation of external anode：The magnesium phosphate cement YanPVCGuan Bi cast mixed is entered, waits for magnesium phosphate water condensation After take out test specimen, test specimen is wrapped up with carbon cloth；In short transverse, it should ensure that carbon cloth is higher by concrete upper surface 25mm is used for the connection of electrode；The test specimen wrapped is again placed in pvc pipe, the second pouring of magnesium phosphate cement is carried out；It pours Note finishes, and takes out test specimen after the condensation of surface layer magnesium phosphate cement, conserves 28d, obtains magnesium phosphate cement and bonds carbon cloth anode Material；
4. concrete sample dechlorinates：3. the middle second pouring test specimen conserved is placed in modified Nano silicic acid calcium solution, Liquid surface height controlling does anode concordant with test specimen upper surface, with carbon cloth, and concrete core reinforcing bar is cathode, is connected with conducting wire It picks up and, external dc power supply, using intermittent energization, preceding 14d current densities control is in 2A/m2, 7d is powered off, subsequent electric current is close Degree control is in 1A/m2, current density size is calculated with specific surface area relative to reinforcing bar；Whole cycle is 28d, to mixed Solidifying soil test specimen dechlorinates.
1, Related Mechanism and parameter declaration are as follows：
(1) magnesium phosphate cement related description：Magnesium phosphate cement is with magnesia, phosphate, retarder and mineral admixture It prepares by a certain percentage, reaction essence is the exothermic reaction of acid-base neutralization, and condensation hardening is rapid.Magnesium phosphate cement each component ratio Example influences its performance very big：M/P is too low and excessively high, and phosphate and magnesia residual quantity are excessive in system, to magnesium phosphate cement Intensity effect is larger.Therefore by experimental study, when determining that M/P is 4~5, the performance of magnesium phosphate cement is best；The addition of retarder Primarily to slowing down reaction rate, retarder can form coating film on magnesium oxide particle surface, prevent the dissolution of magnesium ion, Reduce reaction rate.Most common retarder is borax, and when its volume is less than 5%, retarding effect is poor, when being more than 10%, Although Slow setting time is extended, the loss of strength of magnesium phosphate cement is larger.Therefore, by experimental study, slow setting is determined The volume of agent is 5%~10%.Influence of the water-cement ratio to magnesium phosphate cement is also larger, and water-cement ratio is too small, the stream of magnesium phosphate cement Dynamic property is poor, and water-cement ratio is excessive, and magnesium phosphate cement loss of strength is serious.Therefore, by experimental study, determine water-cement ratio be 0.14~ 0.16。
(2) conductive material：There is carbon nanotube good electric conductivity, its addition to have to the magnesium phosphate cement of poorly conductive Improve well.Meanwhile carbon nanotube has very high tensile strength, is added into magnesium phosphate cement, can make magnesium phosphate cement It bonds carbon fiber reinforced polymers and shows good intensity, elasticity, fatigue resistance and isotropism, give the performance of composite material Bring great improvement.
(3) electrolyte：Traditional electrolyte is all some aqueous slkalis, and after its extraction, microcell goes out inside steel-concrete Now softening, porous phenomenon are damaged concrete performance serious.For nanometer calcium silicates by modified, surface is positively charged, makees in electric field Enter inside concrete with lower, on the one hand, because of its nano effect, inside concrete gap can be refined, on the other hand introduced SiO3 2-It can be with the Ca (OH) in concrete2Reaction generates C-S-H gels, is repaired to concrete inner structure.
(4) selection of carbon cloth：It is titanium net anode that tradition, which is most widely used, why selects carbon cloth, first First, conductivity is 15 times or so of titanium net anode, can improve the extraction efficiency of chlorion；It secondly, can be with magnesium phosphate Cement is bound together use, and effect of extracting is reached while reinforcing to concrete structure.
2, realize that the concrete operation step of Chloride Ion in Concrete extraction is as follows：
(1) preparation of concrete sample：The match ratio of concrete sample is：PO42.5 cement 480kg/m3, fine aggregate 622kg/m3, coarse aggregate 1106kg/m3, polycarboxylate water-reducer 1.5L/m3, water 192L/m3, it is water inside to mix villaumite (NaCl) content The 4% of shale amount.By said ratio, design concrete sample size is Φ 150 × 300, bar diameter D=10mm, and reinforcing bar exists Insertion depth in concrete is 250m, the reinforcing bar for exposing concrete surface is wrapped up with epoxy resin, in standard conditions Lower maintenance 28d.
(2) processing of concrete surface：The concrete of maintenance to certain age is taken out, its surface be polishing to flat It is whole, place it in the center of the pvc pipe bigger 10mm than its diameter.
(3) prepared by modified phosphate magnesium cement：Potassium dihydrogen phosphate, borax and conductive material carbon nanotube are mixed by a certain percentage It closes uniformly, adds water to stir 5min, dead roasting magnesia is then added, stirs evenly.
(4) preparation of external anode：The magnesium phosphate cement YanPVCGuan Bi cast mixed is entered, waits for magnesium phosphate water-setting Test specimen is taken out after knot, test specimen is wrapped up with carbon cloth, in short transverse, should ensure that carbon cloth is higher by concrete upper table Face 25mm is used for the connection of electrode.Time after wrapping is again placed in pvc pipe, the secondary of magnesium phosphate cement is carried out and pours Note.It is poured, takes out test specimen after the condensation of surface layer magnesium phosphate cement, be placed under standard environment and conserve 28d, obtain magnesium phosphate water Mud bonds the anode material of carbon cloth.
(5) concrete sample dechlorinates：The second pouring test specimen conserved in (3) is placed in modified Nano silicic acid calcium solution In, liquid surface height controlling does anode concordant with test specimen, with carbon cloth, and concrete core reinforcing bar is cathode, is connected with conducting wire Get up, external dc power supply, using intermittent energization, early stage, the control of (preceding 14d) current density was in 2A/m2(relative to reinforcing bar Specific surface area), 7d is powered off, subsequent current density control is in 1A/m2, whole cycle 28d dechlorinates to concrete sample.
(6) it is to ensure that electrolyte ph is maintained at 12 or more, electrolyte is replaced every 2d.After dechlorination, to coagulation Native test specimen drilling takes powder, tests the content of chlorion in concrete sample.
(5), relevant parameter is described as follows in (6)：The extraction efficiency of chlorion declines as extraction time extends.It is early Phase, soluble chlorine ion concentration is high in concrete, is extracted using high current density, with the progress of extraction, concrete Middle free chloride ion content reduces, and extraction efficiency declines.Power-off 7d be in order to which Chloride Ion in Concrete further redistributes, It in the case that chloride ion content is relatively low, is extracted using small current density, can effectively reduce armored concrete performance Damage.Meanwhile pH value be more than 9 when can effectively prevent chlorine generation.
Specific implementation mode
Magnesium phosphate cement further to embody different conductive capabilities is bonded carbon cloth and makees external anode to concrete The effect of extracting of middle chlorion and the modified nano calcium carbonate of various concentration to the repairing effect of inside concrete after dechlorination, under Face combines concrete case, and the present invention is described in more detail.
Example 1：
A kind of improved method of electrochemistry extraction Chloride Ion in Concrete, anode material is with when concentration of electrolyte by described It is required that as follows：
(1) molar ratio of dead roasting MgO (M) and potassium dihydrogen phosphate (P)：M/P=4；
(2) borax retarder volume：It is the 5wt% of magnesia quality；
(3) water-cement ratio：W/C=0.14；
(4) carbon nanotube volume：It is the 0.01% of magnesia quality；
(5) mass percent concentration of modified Nano calcium silicates：10%；
(6) carbon cloth：Tensile strength >=2500MPa, every meter of resistance：35~40 Ω/m.
According to requiring, modified phosphate magnesium cement bonds the step of carbon cloth makees anode material extraction Chloride Ion in Concrete And extraction parameters are as follows：
1. the processing of concrete surface：It will conserve to the concrete of 28d and take out, and to its surface be polishing to smooth, general It is placed in the center of the pvc pipe bigger 10mm than its diameter.
2. prepared by modified phosphate magnesium cement：Potassium dihydrogen phosphate, borax and conductive material carbon nanotube are uniformly mixed, water is added 5min is stirred, dead roasting magnesia is then added, stirs evenly.
3. the preparation of external anode：The magnesium phosphate cement YanPVCGuan Bi cast mixed is entered, waits for magnesium phosphate water condensation After take out test specimen, test specimen is wrapped up with carbon cloth, in short transverse, should ensure that carbon cloth is higher by concrete upper surface 25mm is used for the connection of electrode.Time after wrapping is again placed in pvc pipe, the second pouring of magnesium phosphate cement is carried out. It is poured, takes out test specimen after the condensation of surface layer magnesium phosphate cement, be placed under standard environment and conserve 28d, obtain magnesium phosphate cement Bond the anode material of carbon cloth.
4. concrete sample dechlorinates：The second pouring test specimen conserved in (3) is placed in modified Nano silicic acid calcium solution, Liquid surface height controlling does anode concordant with test specimen upper surface, with carbon cloth, and concrete core reinforcing bar is cathode, is connected with conducting wire It picks up and, external dc power supply, using intermittent energization, early stage, the control of (preceding 14d) current density was in 2A/m2(relative to reinforcing bar Specific surface area), power off 7d, the control of subsequent current density is in 1A/m2, whole cycle 28d removes concrete sample Chlorine.
Example 2：
A kind of improved method of electrochemistry extraction Chloride Ion in Concrete, anode material proportioning, concentration of electrolyte is by described It is required that as follows：
(1) molar ratio of dead roasting MgO (M) and potassium dihydrogen phosphate (P)：M/P=4.5；
(2) borax retarder volume：It is the 8wt% of magnesia quality；
(3) water-cement ratio：W/C=0.15；
(4) carbon nanotube volume：It is the 0.03% of magnesia quality；
(5) modified Nano calcium silicates mass percent concentration：13%；
(6) carbon cloth：Tensile strength >=2500MPa, every meter of resistance：35~40 Ω/m.
According to requiring, modified phosphate magnesium cement bonds the step of carbon cloth makees anode material extraction Chloride Ion in Concrete And extraction parameters are as follows：
1. the processing of concrete surface：It will conserve to the concrete of 28d and take out, and to its surface be polishing to smooth, general It is placed in the center of the pvc pipe bigger 10mm than its diameter.
2. prepared by modified phosphate magnesium cement：Potassium dihydrogen phosphate, borax and conductive material carbon nanotube are uniformly mixed, water is added 5min is stirred, dead roasting magnesia is then added, stirs evenly.
3. the preparation of external anode：The magnesium phosphate cement YanPVCGuan Bi cast mixed is entered, waits for magnesium phosphate water condensation After take out test specimen, test specimen is wrapped up with carbon cloth, in short transverse, should ensure that carbon cloth is higher by concrete upper surface 25mm is used for the connection of electrode.Time after wrapping is again placed in pvc pipe, the second pouring of magnesium phosphate cement is carried out. It is poured, takes out test specimen after the condensation of surface layer magnesium phosphate cement, be placed under standard environment and conserve 28d, obtain magnesium phosphate cement Bond the anode material of carbon cloth.
4. concrete sample dechlorinates：The second pouring test specimen conserved in (3) is placed in modified Nano silicic acid calcium solution, Liquid surface height controlling does anode concordant with test specimen upper surface, with carbon cloth, and concrete core reinforcing bar is cathode, is connected with conducting wire It picks up and, external dc power supply, using intermittent energization, early stage, the control of (preceding 14d) current density was in 2A/m2(relative to reinforcing bar Specific surface area), power off 7d, the control of subsequent current density is in 1A/m2, whole cycle 28d removes concrete sample Chlorine.
Example 3：
A kind of improved method of electrochemistry extraction Chloride Ion in Concrete, anode material proportioning, concentration of electrolyte is by described It is required that as follows：
(1) molar ratio of dead roasting MgO (M) and potassium dihydrogen phosphate (P)：M/P=5；
(2) borax retarder volume：It is the 10wt% of magnesia quality；
(3) water-cement ratio：W/C=0.16；
(4) carbon nanotube volume：It is the 0.05% of magnesia quality；
(5) modified Nano calcium silicates mass percent concentration：15%；
(6) carbon cloth：Tensile strength >=2500MPa, every meter of resistance：35~40 Ω/m.
According to requiring, modified phosphate magnesium cement bonds the step of carbon cloth makees anode material extraction Chloride Ion in Concrete And extraction parameters are as follows：
1. the processing of concrete surface：It will conserve to the concrete of 28d and take out, and to its surface be polishing to smooth, general It is placed in the center of the pvc pipe bigger 10mm than its diameter.
2. prepared by modified phosphate magnesium cement：Potassium dihydrogen phosphate, borax and conductive material carbon nanotube are uniformly mixed, water is added 5min is stirred, dead roasting magnesia is then added, stirs evenly.
3. the preparation of external anode：The magnesium phosphate cement YanPVCGuan Bi cast mixed is entered, waits for magnesium phosphate water condensation After take out test specimen, test specimen is wrapped up with carbon cloth, in short transverse, should ensure that carbon cloth is higher by concrete upper surface 25mm is used for the connection of electrode.Time after wrapping is again placed in pvc pipe, the second pouring of magnesium phosphate cement is carried out. It is poured, takes out test specimen after the condensation of surface layer magnesium phosphate cement, be placed under standard environment and conserve 28d, obtain magnesium phosphate cement Bond the anode material of carbon cloth.
4. concrete sample dechlorinates：The second pouring test specimen conserved in (3) is placed in modified Nano silicic acid calcium solution, Liquid surface height controlling makees anode concordant with test specimen upper surface, with carbon cloth, and concrete core reinforcing bar is cathode, is connected with conducting wire It picks up and, external dc power supply, using intermittent energization, early stage, the control of (preceding 14d) current density was in 2A/m2(relative to reinforcing bar Specific surface area), power off 7d, the control of subsequent current density is in 1A/m2, whole cycle 28d removes concrete sample Chlorine.
Application example
After dechlorination, with reference to SL352-2006《Concrete for hydraulic structure testing regulations》Measure the Water soluble chloride ion in concrete Concentration, the dechlorination effect being calculated are as shown in table 1；According to GB/T50081-2002《Normal concrete mechanical property test side Method standard》Reinforcing bar-concrete interface adhesion strength is tested, shown in table 2.
(1) chlorine removal rate
Example 1-3, the chlorine removal rate for making external anode by modified phosphate magnesium bonding carbon cloth are as shown in table 1.
1 modified phosphate magnesium of table bonds the chlorine removal rate (wt%) that carbon cloth makees external anode
Group number Example 1 Example 2 Example 3 Control group
Chlorine removal rate (%) 71.7 75.9 78.2 66.8
(note：Control group is traditional titanium net anode material with Ca (OH)2For the chlorine removal rate of electrolyte)
(2) the loss of bond strength rate of steel-concrete
Example 1-3 bonds carbon cloth by modified phosphate magnesium and makees external anode, makees electrolyte with modified Nano calcium silicates The loss late of steel-concrete adhesion strength is as shown in table 2 after dechlorination
The loss late (%) of 2 armored concrete adhesion strength of table
Group number Example 1 Example 2 Example 3 Control group
δLoss(%) 8.1 6.2 4.7 12.5
(note：Control group is traditional titanium net anode material with Ca (OH)2Steel-concrete bonds strong after dechlorinating for electrolyte The loss late of degree)
As can be seen from Table 1 and Table 2：With the cementing carbon cloth of carbon nano-tube modification magnesium phosphate cement to concrete component Chlorine removal rate is all higher than the chlorine removal rate that traditional titanium net anode material does anode, and makees electrolyte extraction with modified Nano calcium silicates When taking Chloride Ion in Concrete, the loss of cohesive force between steel-concrete can be effectively reduced.

Claims (5)

1. a kind of improved method of electrochemistry extraction Chloride Ion in Concrete, it is characterised in that pass through the magnesium phosphate to poorly conductive Cement is modified, and bonding carbon cloth with it makees external anode material, using modified Nano calcium silicates as electrolyte, is added in dechlorination Gu while concrete inner structure is repaired；The material it is as follows with when parameter：
(1) the molar ratio M/P of dead roasting MgO (M) and phosphate (P)：4~5；
(2) retarder volume：It is 5~10wt% of magnesia quality；
(3) water-cement ratio：0.14~0.16；
(4) conductive material volume：It is the 0.01%~0.05% of magnesia quality；
(5) electrolyte quality percent concentration：10%~15%；
(6) carbon cloth：Tensile strength >=2500MPa, every meter of resistance：35~40 Ω/m.
2. a kind of improved method of electrochemistry extraction Chloride Ion in Concrete according to claim 1, which is characterized in that dead The calcination temperature of MgO is burnt at 1600 DEG C or more, and the phosphate is PHOSPHORIC ACID TECH.GRADE potassium dihydrogen.
3. a kind of improved method of electrochemistry extraction Chloride Ion in Concrete according to claim 1, which is characterized in that institute It is borax to state retarder.
4. a kind of improved method of electrochemistry extraction Chloride Ion in Concrete according to claim 1, which is characterized in that institute The conductive material stated is carbon nanotube.
5. a kind of improved method of electrochemistry extraction Chloride Ion in Concrete according to claim 1, which is characterized in that change Property magnesium phosphate cement bonding carbon cloth make concrete electrochemical dechlorination external anode, it is real in modified Nano calcium silicates electrolyte The extraction of existing concrete component chlorion, implementation steps are as follows：
1. the processing of concrete surface：The concrete of maintenance to 28d is taken out, its surface be polishing to smooth, is set In the center of the pvc pipe bigger than its diameter；
2. prepared by modified phosphate magnesium cement：Phosphate, retarder and conductive material are uniformly mixed, add water to stir 5min, then Dead MgO is added, stirs evenly, water-cement ratio is 0.14~0.16；
3. the preparation of external anode：The magnesium phosphate cement YanPVCGuan Bi cast mixed is entered, is taken after magnesium phosphate water condensation Go out test specimen, test specimen is wrapped up with carbon cloth；In short transverse, it should ensure that carbon cloth is higher by concrete upper surface 25mm is used for the connection of electrode；The test specimen wrapped is again placed in pvc pipe, the second pouring of magnesium phosphate cement is carried out；It pours Note finishes, and takes out test specimen after the condensation of surface layer magnesium phosphate cement, conserves 28d, obtains magnesium phosphate cement and bonds carbon cloth anode Material；
4. concrete sample dechlorinates：3. the middle second pouring test specimen conserved is placed in modified Nano silicic acid calcium solution, liquid level Height control does anode concordant with test specimen upper surface, with carbon cloth, and concrete core reinforcing bar is cathode, is connected with conducting wire Come, external dc power supply, using intermittent energization, preceding 14d current densities control is in 2A/m2, power off 7d, subsequent current density control System is in 1A/m2, current density size is calculated with specific surface area relative to reinforcing bar；Whole cycle is 28d, to concrete Test specimen dechlorinates.
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