CN112500012A - Rust inhibitor for improving rust resistance of steel bar in concrete or mortar and application thereof - Google Patents

Rust inhibitor for improving rust resistance of steel bar in concrete or mortar and application thereof Download PDF

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Publication number
CN112500012A
CN112500012A CN202011263816.5A CN202011263816A CN112500012A CN 112500012 A CN112500012 A CN 112500012A CN 202011263816 A CN202011263816 A CN 202011263816A CN 112500012 A CN112500012 A CN 112500012A
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China
Prior art keywords
concrete
rust
nitrite
corrosion
rust inhibitor
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Pending
Application number
CN202011263816.5A
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Chinese (zh)
Inventor
柳俊哲
巴明芳
贺智敏
王建民
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Ningbo University
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Ningbo University
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Priority to CN202011263816.5A priority Critical patent/CN112500012A/en
Publication of CN112500012A publication Critical patent/CN112500012A/en
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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
    • C04B40/0028—Aspects relating to the mixing step of the mortar preparation
    • C04B40/0039—Premixtures of ingredients
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
    • C04B28/04—Portland cements
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
    • C04B2103/60—Agents for protection against chemical, physical or biological attack
    • C04B2103/61—Corrosion inhibitors
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/20—Resistance against chemical, physical or biological attack
    • C04B2111/26—Corrosion of reinforcement resistance

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)

Abstract

The invention discloses a rust inhibitor for improving the rust resistance of a steel bar in concrete or mortar and application thereof, wherein the rust inhibitor comprises the following components in percentage by mass: 50-75% of sulfate and the balance of nitrite; the corrosion inhibitor has the advantages that sulfate is added into the original nitrite component, the sulfate can react with mineral substances in concrete, chlorine salt in the concrete is chemically solidified, the content of free chloride ions is reduced, the corrosion effect of the free chloride ions on steel bars is reduced, the critical value of the chloride ions for exciting the corrosion of the steel bars can be improved by 2-3 times through the nitrite, the combination effect of the sulfate and the nitrite can greatly prolong the excitation time of the corrosion of the steel bars, and the corrosion of the steel bars is effectively inhibited.

Description

Rust inhibitor for improving rust resistance of steel bar in concrete or mortar and application thereof
Technical Field
The invention relates to a rust inhibitor for a reinforced concrete structure, in particular to a rust inhibitor for improving the rust resistance of a reinforced steel bar in concrete or mortar and application thereof.
Background
The factors causing the corrosion of the steel reinforcement, although multifaceted, have been shown to be mainly due to chloride ions in the case of a number of structural failures of reinforced concrete. The chloride ions are mainly from deicing salt, marine environment, chloride salt admixture, sea sand and the like. In countries and regions where deicing salt and chloride salt admixtures are used in winter and where a large amount of sea sand is used, the corrosion damage of steel bars mainly based on infrastructure is particularly serious.
In recent years, a great deal of literature reports are available at home and abroad for the research on the incorporation of the rust inhibitor into concrete to protect steel bars. The use of the rust inhibitor can improve the passivation environment of the surface of the reinforcement in the concrete, so that the reinforcement is not rusted under the condition of higher chloride ion content. The reinforcing steel bar rust inhibitor can play two roles: on one hand, the initial time of rusting of the steel bar is delayed; on the other hand, the steel bar corrosion development speed is slowed down. Currently, corrosion inhibitors such as benzotriazole, amine and enamine, borate, molybdate, zinc oxide, gluconate, urotropine, resorcinol, phloroglucinol, sodium benzoate, stannous chloride, chromium salt, phosphate, fatty acid, alcohol, ester and the like which are sold in the market are used in reinforced concrete, and the nitrite corrosion inhibitor is considered to have the most obvious effect after the natural potential is measured. Nitrite is used as an antifreezing agent, an early strength agent and a rust-resisting component in concrete or mortar and is widely applied to reinforced concrete structures, the mixing amount is generally 1-3% of the mass of cement, the performance of the concrete or mortar can be influenced when the mixing amount is too large and too small, the early strength and the antifreezing and rust-resisting effects are not obvious when the mixing amount is small, and particularly when the nitrite is used as a rust-resisting agent, local corrosion can be generated when the mixing amount is insufficient, and the efficacy and the durability of the nitrite are influenced when the mixing amount is too large, so that the popularization and application of the nitrite rust-resisting agent are limited to a certain extent, and the improvement of the performance of the nitrite rust-resisting agent becomes an important direction for improving the durability of modern concrete.
Disclosure of Invention
The invention aims to provide a rust inhibitor for improving the rust resistance of a steel bar in concrete or mortar and application thereof.
The technical scheme adopted by the invention for solving the technical problems is as follows: the rust inhibitor for improving the rust resistance of the steel bar in concrete or mortar comprises the following components in parts by mass: 50-75% of sulfate and the balance of nitrite.
Further, the sulfate is barium sulfate. The rust inhibitor disclosed by the invention takes barium sulfate as a main component, can react with mineral substances in concrete, so that chloride salt in the concrete is chemically cured, and the content of free chloride ions is reduced, so that the corrosion action of the free chloride ions on steel bars is reduced, and the corrosion of the steel bars is effectively inhibited.
Further, the nitrite is calcium nitrite.
The invention also aims to provide the application of the rust inhibitor in concrete or mortar: the mixing amount of the rust inhibitor is 1-6% of the mass of cement in concrete or mortar. If the mixing amount of the rust inhibitor is too low, the rust inhibiting effect is not obvious, and the purpose of rust inhibition cannot be achieved; the efficacy and durability of the rust inhibitor are affected by too high a mixing amount of the rust inhibitor.
Compared with the prior art, the corrosion inhibitor has the advantages that sulfate is added into the original nitrite component, the sulfate can react with mineral substances in concrete, chlorine salt in the concrete is chemically cured, the content of free chloride ions is reduced, the corrosion action of the free chloride ions on reinforcing steel bars is reduced, the critical value of the chloride ions for exciting the corrosion of the reinforcing steel bars is improved by 2-3 times through the nitrite, the excitation time of the corrosion of the reinforcing steel bars can be greatly prolonged through the combined action of the sulfate and the nitrite, and the corrosion of the reinforcing steel bars is effectively inhibited.
Drawings
FIG. 1 is a diagram of the dry-wet cycle process of the steel bar corrosion test of the test pieces 1-7 according to the embodiment of the present invention;
FIG. 2 is a graph showing the natural potential change measured in a steel bar corrosion test of test pieces 1 to 7 according to an embodiment of the present invention;
FIG. 3 is a graph showing the change in penetration depth measured in the chloride ion penetration test for test pieces 1 to 7 prepared in the embodiment of the present invention;
FIG. 4 is a graph showing pore volumes of test pieces 1 to 7 obtained in accordance with the embodiment of the present invention in pore structure measurement;
FIG. 5 is a graph showing the total chloride ion content of test pieces 1 to 7 obtained in the embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the accompanying examples.
Example 1:
a rust inhibitor A for improving the rust resistance of reinforcing steel bars in concrete or mortar comprises 50% of barium sulfate and 50% of calcium nitrite.
Example 2:
a rust inhibitor B for improving the rust resistance of reinforcing steel bars in concrete or mortar comprises 60% of barium sulfate and 40% of calcium nitrite.
Example 3:
a rust inhibitor C for improving the rust resistance of reinforcing steel bars in concrete or mortar comprises 75% of barium sulfate and 25% of calcium nitrite.
The rust inhibitor A, B, C is respectively added into concrete, and the pouring of the reinforced concrete test piece is carried out, specifically:
example 4:
s1: according to the water: 300kg/m3And, portland cement: 450kg/m3And river sand: 1300kg/m3The rust inhibitor C accounting for 4% of the mass of the cement is proportioned and mixed to prepare concrete;
s2: cutting the Q235 reinforcing steel bar into short reinforcing steel bars with the length of 390mm, sealing the positions, 5mm away from the two sides of the column of the short reinforcing steel bars, of which the two sides are sealed by epoxy resin, taking the end faces as working faces, and pouring the concrete obtained in the step S1 to obtain a test piece 1.
Example 5:
s1: according to the water: 300kg/m3And, portland cement: 450kg/m3And river sand: 1300kg/m3The rust inhibitor B accounting for 5 percent of the mass of the cement is proportioned and mixed to prepare concrete;
s2: cutting the Q235 reinforcing steel bar into short reinforcing steel bars with the length of 390mm, sealing the positions, 5mm away from the two sides of the column of the short reinforcing steel bars, of which the two sides are sealed by epoxy resin, taking the end faces as working faces, and pouring the concrete obtained in the step S1 to obtain a test piece 2.
Example 6:
s1: according to the water: 300kg/m3And, portland cement: 450kg/m3And river sand: 1300kg/m3The rust inhibitor A accounting for 6 percent of the mass of the cement is proportioned and mixed to prepare concrete;
s2: cutting the Q235 reinforcing steel bar into short reinforcing steel bars with the length of 390mm, sealing the positions, 5mm away from the two sides of the column of the short reinforcing steel bars, of which the two sides are sealed by epoxy resin, taking the end faces as working faces, and pouring the concrete obtained in the step S1 to obtain a test piece 3.
Comparative example 1:
under the condition of not adding any rust inhibitor, the pouring of the reinforced concrete test piece is directly carried out, and the concrete steps are as follows:
s1: according to the water: 300kg/m3And, portland cement: 450kg/m3And river sand: 1300kg/m3Mixing the components in proportion to prepare concrete;
s2: cutting the Q235 reinforcing steel bar into short reinforcing steel bars with the length of 390mm, sealing the positions, 5mm away from the two sides of the column of the short reinforcing steel bars, of which the two sides are sealed by epoxy resin, taking the end faces as working faces, and pouring the concrete obtained in the step S1 to obtain a test piece 4.
Comparative example 2:
a rust inhibitor D for improving the rust inhibiting performance of reinforcing steel bars in concrete or mortar comprises calcium nitrite.
Respectively adding the rust inhibitor D into concrete, and pouring a reinforced concrete test piece, wherein the concrete steps are as follows:
comparative example 3:
s1: according to the water: 300kg/m3And, portland cement: 450kg/m3And river sand: 1300kg/m3The rust inhibitor D accounting for 1 percent of the mass of the cement is proportioned and mixed to prepare concrete;
s2: cutting the Q235 reinforcing steel bar into short reinforcing steel bars with the length of 390mm, sealing the positions, 5mm away from the two sides of the column of the short reinforcing steel bars, of which the two sides are sealed by epoxy resin, taking the end faces as working faces, and pouring the concrete obtained in the step S1 to obtain a test piece 5.
Comparative example 4:
s1: according to the water: 300kg/m3And, portland cement: 450kg/m3And river sand: 1300kg/m3The rust inhibitor D accounting for 2 percent of the mass of the cement is proportioned and mixed to prepare concrete;
s2: the Q235 reinforcing steel bar was cut into a short reinforcing steel bar having a length of 390mm, and 5mm positions on both sides of the column of the short reinforcing steel bar were sealed with epoxy resin, and the concrete obtained in S1 was poured using the end face as the working face to obtain a test piece 6.
Comparative example 5:
s1: according to the water: 300kg/m3And, portland cement: 450kg/m3And river sand: 1300kg/m3The rust inhibitor D accounting for 3% of the mass of the cement is proportioned and mixed to prepare concrete;
s2: the Q235 reinforcing steel bar was cut into a short reinforcing steel bar having a length of 390mm, and 5mm positions on both sides of the column of the short reinforcing steel bar were sealed with epoxy resin, and the concrete obtained in S1 was poured using the end face as the working face to obtain a test piece 7.
The results of the rust inhibition effect test on the 7 test pieces are as follows:
steel bar corrosion test
The test pieces 1-7 were demolded 1 day after molding, the surfaces were wrapped with plastic films and sealed and cured at 20 ℃ for 28 days, then the dry-wet cycle shown in fig. 1 was performed for 30 times to accelerate the corrosion of the reinforcing steel bars in the concrete, and the natural potential after the corrosion was measured after every two dry-wet cycles, and the measured natural potential was shown in fig. 2.
As can be seen from the attached figure 2, the natural potential of the test piece not doped with the calcium nitrite and the barium sulfate is obviously reduced after dry-wet circulation, even reaches about-500 mV (SCE), and the test piece is corroding at a probability of 90% according to the ASTM standard, but the natural potential of the test piece doped with the nitrite is about-360 mV after 30 dry-wet circulation, and the rust resistance effect of the mortar test piece doped with the barium sulfate in the nitrite is obviously improved.
II, chloride ion permeation test: the concrete part of the test piece 1-7 with the side epoxy resin coated with the waterproof treatment is taken and soaked in 3 percent sodium chloride solution at 20 ℃ to lead chloride ions to migrate in the concrete, and color reaction is carried out by utilizing 0.1N silver nitrate solution, the penetration depth of the chloride ions is measured, and the measured penetration depth is shown as figure 3.
As can be seen from FIG. 3, the test piece doped with calcium nitrite and barium sulfate has a significant effect of inhibiting the penetration of chloride ions, especially the test piece doped with barium sulfate can reduce the penetration depth by about 32%, compared with the reference test piece not doped with calcium nitrite and barium sulfate.
Thirdly, measuring the pore structure and the total amount of chloride ions: taking the concrete part of the molded and cured test piece 1-7, lightly knocking the concrete part into small blocks with the diameter of about 10mm and no surface abrasion by using a small iron hammer, keeping the original pore structure as much as possible, brushing powder on the surfaces of the small cement blocks by using a brush, then cleaning the small cement blocks by using absolute alcohol, and performing the pore structure measurement and the chloride ion content measurement on the test piece, wherein the measurement results are respectively shown in fig. 4 and fig. 5.
As can be seen from FIG. 4, the porosity of the test piece doped with the calcium nitrite and the barium sulfate is obviously reduced compared with the test piece doped with the nitrite alone. As can be seen from FIG. 5, the total content of the cured chloride ions in the test piece which is doped with calcium nitrite and barium sulfate is obviously increased compared with the single-doped calcium nitrite rust inhibitor, which shows that barium sulfate has obvious effect on curing chloride ions.
The scope of the present invention includes, but is not limited to, the above embodiments, and the present invention is defined by the appended claims, and any alterations, modifications, and improvements that may occur to those skilled in the art are all within the scope of the present invention.

Claims (4)

1. The rust inhibitor for improving the rust resistance of the steel bar in concrete or mortar is characterized in that: the rust inhibitor comprises the following components in percentage by mass: 50-75% of sulfate and the balance of nitrite.
2. The rust inhibitor for improving the rust inhibition performance of a steel bar in concrete or mortar as claimed in claim 1, wherein: the sulfate is barium sulfate.
3. The rust inhibitor for improving the rust inhibition performance of a steel bar in concrete or mortar as claimed in claim 1, wherein: the nitrite is calcium nitrite.
4. Use of the rust inhibitor according to any one of claims 1 to 3 in concrete or mortar, wherein the amount of said rust inhibitor is 1-6% by mass of the cement in the concrete or mortar.
CN202011263816.5A 2020-11-12 2020-11-12 Rust inhibitor for improving rust resistance of steel bar in concrete or mortar and application thereof Pending CN112500012A (en)

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Application Number Priority Date Filing Date Title
CN202011263816.5A CN112500012A (en) 2020-11-12 2020-11-12 Rust inhibitor for improving rust resistance of steel bar in concrete or mortar and application thereof

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101303967B1 (en) * 2012-12-05 2013-09-05 (주)정상 엔지니어링 Anti-saltdamage coating film composition of waterproof materials using fly ash, the coating method thereof, and the manufacturing method thereof
CN110204239A (en) * 2019-04-11 2019-09-06 武汉理工大学 A kind of lithium slag admixture and its preparation method and application
CN110255951A (en) * 2019-04-11 2019-09-20 武汉理工大学 A kind of barium base chloride ion curing agent and its preparation method and application

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101303967B1 (en) * 2012-12-05 2013-09-05 (주)정상 엔지니어링 Anti-saltdamage coating film composition of waterproof materials using fly ash, the coating method thereof, and the manufacturing method thereof
CN110204239A (en) * 2019-04-11 2019-09-06 武汉理工大学 A kind of lithium slag admixture and its preparation method and application
CN110255951A (en) * 2019-04-11 2019-09-20 武汉理工大学 A kind of barium base chloride ion curing agent and its preparation method and application

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
于玲等: "《海排灰在道路基层及底基层中的应用研究》", 31 December 2018, 合肥工业大学出版社 *
马世豪等: "钢筋阻锈剂的阻锈机理及性能评价的研究进展", 《腐蚀与防护》 *

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