CA2300614A1 - Process for reducing and preventing corrosion and corrosion progress on reinforcing steels of reinforced concrete structures - Google Patents
Process for reducing and preventing corrosion and corrosion progress on reinforcing steels of reinforced concrete structures Download PDFInfo
- Publication number
- CA2300614A1 CA2300614A1 CA 2300614 CA2300614A CA2300614A1 CA 2300614 A1 CA2300614 A1 CA 2300614A1 CA 2300614 CA2300614 CA 2300614 CA 2300614 A CA2300614 A CA 2300614A CA 2300614 A1 CA2300614 A1 CA 2300614A1
- Authority
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- Canada
- Prior art keywords
- corrosion
- gel
- reinforced concrete
- emulsion
- waterproofing
- 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.)
- Abandoned
Links
- 238000005260 corrosion Methods 0.000 title claims abstract description 40
- 230000007797 corrosion Effects 0.000 title claims abstract description 40
- 239000011150 reinforced concrete Substances 0.000 title claims abstract description 21
- 238000000034 method Methods 0.000 title claims abstract description 16
- 230000008569 process Effects 0.000 title claims abstract description 14
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 13
- 239000010959 steel Substances 0.000 title claims abstract description 13
- 230000003014 reinforcing effect Effects 0.000 title claims abstract description 10
- 239000003112 inhibitor Substances 0.000 claims abstract description 21
- 238000004078 waterproofing Methods 0.000 claims abstract description 18
- 150000004756 silanes Chemical class 0.000 claims abstract description 8
- -1 siloxanes Chemical class 0.000 claims abstract description 5
- 230000002401 inhibitory effect Effects 0.000 claims abstract description 4
- 239000000126 substance Substances 0.000 claims description 8
- 239000007864 aqueous solution Substances 0.000 claims description 3
- 238000000576 coating method Methods 0.000 claims description 3
- 239000002562 thickening agent Substances 0.000 claims description 3
- 239000003085 diluting agent Substances 0.000 claims description 2
- 239000002904 solvent Substances 0.000 claims description 2
- 239000000839 emulsion Substances 0.000 claims 8
- 150000001414 amino alcohols Chemical class 0.000 claims 1
- 239000011248 coating agent Substances 0.000 claims 1
- 239000000203 mixture Substances 0.000 abstract description 7
- 230000002209 hydrophobic effect Effects 0.000 abstract description 3
- 235000011837 pasties Nutrition 0.000 abstract description 2
- 239000004567 concrete Substances 0.000 description 14
- 239000000243 solution Substances 0.000 description 13
- 239000003223 protective agent Substances 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 239000004566 building material Substances 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 6
- 230000035515 penetration Effects 0.000 description 4
- 230000008439 repair process Effects 0.000 description 4
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 3
- 239000000654 additive Substances 0.000 description 3
- 239000012752 auxiliary agent Substances 0.000 description 3
- 239000004568 cement Substances 0.000 description 3
- 239000006071 cream Substances 0.000 description 3
- 239000004570 mortar (masonry) Substances 0.000 description 3
- 239000003973 paint Substances 0.000 description 3
- 229910000077 silane Inorganic materials 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- UEEJHVSXFDXPFK-UHFFFAOYSA-N N-dimethylaminoethanol Chemical compound CN(C)CCO UEEJHVSXFDXPFK-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000003763 carbonization Methods 0.000 description 2
- 229960002887 deanol Drugs 0.000 description 2
- 239000012972 dimethylethanolamine Substances 0.000 description 2
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical compound [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- XGRSAFKZAGGXJV-UHFFFAOYSA-N 3-azaniumyl-3-cyclohexylpropanoate Chemical compound OC(=O)CC(N)C1CCCCC1 XGRSAFKZAGGXJV-UHFFFAOYSA-N 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 1
- 239000001744 Sodium fumarate Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 230000006399 behavior Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000012084 conversion product Substances 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000005191 phase separation Methods 0.000 description 1
- RAFRTSDUWORDLA-UHFFFAOYSA-N phenyl 3-chloropropanoate Chemical compound ClCCC(=O)OC1=CC=CC=C1 RAFRTSDUWORDLA-UHFFFAOYSA-N 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000009993 protective function Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 238000005488 sandblasting Methods 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 229960004711 sodium monofluorophosphate Drugs 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
Classifications
-
- 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
- C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
-
- 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
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/009—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone characterised by the material treated
-
- 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
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
- C04B41/46—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with organic materials
- C04B41/49—Compounds having one or more carbon-to-metal or carbon-to-silicon linkages ; Organo-clay compounds; Organo-silicates, i.e. ortho- or polysilicic acid esters ; Organo-phosphorus compounds; Organo-inorganic complexes
- C04B41/4905—Compounds having one or more carbon-to-metal or carbon-to-silicon linkages ; Organo-clay compounds; Organo-silicates, i.e. ortho- or polysilicic acid esters ; Organo-phosphorus compounds; Organo-inorganic complexes containing silicon
-
- 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
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/60—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only artificial stone
- C04B41/61—Coating or impregnation
- C04B41/62—Coating or impregnation with organic materials
- C04B41/64—Compounds having one or more carbon-to-metal of carbon-to-silicon linkages
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
- E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
- E04C5/015—Anti-corrosion coatings or treating compositions, e.g. containing waterglass or based on another metal
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Aftertreatments Of Artificial And Natural Stones (AREA)
Abstract
A process for reducing and preventing corrosion and corrosion progress on reinforcing steels of reinforced concrete structures, wherein the surface of the reinforced concrete structure is coated with a waterproofing and inhibiting gel which is prepared from waterproofing or hydrophobic silanes or siloxanes and migratable corrosion inhibitors so as to form a gel-like, pasty mixture.
Description
PROCESS FOR REDUCING AND PREVENTING CORROSION AND
CORROSION PROGRESS ON REINFORCING STEELS OF REINFORCED
CONCRETE STRUCTURES
1. Field of the Invention The present invention relates to a process for reducing and preventing corrosion and corrosion progress on reinforcing steels of reinforced concrete structures.
CORROSION PROGRESS ON REINFORCING STEELS OF REINFORCED
CONCRETE STRUCTURES
1. Field of the Invention The present invention relates to a process for reducing and preventing corrosion and corrosion progress on reinforcing steels of reinforced concrete structures.
2. Deacri~tion of the Related Art It has been known for many years that, next to the concentration of corrosion stimulators and the pH-value, the moisture content within a reinforced concrete structure decisively influences corrosion and the corrosion process of reinforcing steels in reinforced concrete. Also known for some time has been the effect of corrosion inhibitors on steel; these corrosion inhibitors are used as concrete admixtures and they are used in the form of a low viscosity solution for treating the surfaces of reinforced concrete.
For example, U.S. Patent No. 4,092,109 describes the use of calcium nitrite as a corrosion inhibitor in reinforced concrete.
Thus far, no process has become known which could be easily manipulated for protecting reinforced concrete surfaces in a practical and pexzcianent manner against the penetration of water and simultaneously for introducing migratable corrosion inhibitors into the existing concrete structure.
Concrete structures which contain corroded reinforcing steels are up to now repaired by mechanically removing the concrete Which is endangered by carbonization or corrosion or has been damaged by chloride; the rust is removed from the reinforcing steels by means of sand blasting methods and the steels are protected by a coat of corrosion protection paint. The subsequent reconstruction of the open concrete structure usually takes place by means of suitable concrete replacement materials (mortars) on the basis of mineral and organic binding agents. The state of the art in this connection can be found in the applicable Standards ZTV-SiB-PCC/SPCC and Rilli-DASTB.
The procedure described above of removing the damaged concrete substance and the subsequent reconstruction by means of corrosion protection paint, adhesive bridge, repair mortar and possibly surface protection paints is cumbersome and expensive.
Added to the significant costs of the repair of damaged reinforced steel structures as described above must be the fact that frequently the desired optical appearance of the original concrete facade is significantly altered by the repaired areas.
All of these aspects have in the past always led to the demand for a repair measure which makes it possible to repair concrete facades without the disadvantages described above.
At this point it must be mentioned that it is known in the art to prevent the penetration of water into the reinforced concrete structure by suitable coatings on the basis of silanes/siloxanes, polymer dispersions and solutions as well as reaction resin coatings, wherein the impregnation with silanes is of particular importance specifically for waterproofing the surfaces of exposed concrete facades.
Suitable compositions of such waterproofing or hydrophobic agents can be found in various patent publications. For example, EP 0 273 867, EP 0 518 324, EP 0 049 365, EP 0 101 816, EP 0 304 497 arid BP 0 385 108 discuss silicon-organic compositions which are used as waterproofing and impregnating solutions of building materials. 8P 0 177 824 already describes a resin-like organopolysiloxane impregnation for the surfaces of structural components, wherein additionally lamellar lattice silicates are added for improving the suitability for use, and wherein the formula contains solvents. PCT/SE95/00287 also discloses the composition of a paste-like hydrophobing or waterproofing agent which is provided with the desired processing consistency by means of a stratified silicate thickener. DE 196 28 035 A for the first time describes an aqueous cream of organosilicon components for waterproofing building materials which are absorbed by the building material without residue.
Corrosion inhibitors are used today especially in the market of the United States of America, but also in some European countries, as an admixture to fresh concrete. For example, EP 0 635 463 describes the use of an admixture for preventing the corrosion in building materials, and CH 686 386 describes the use of corrosion inhibiting amine components as a conversion product with acids for the same use. Moreover, U.S. Patent No. 5,750,053, EP 787 .697, U.S. Patent 5,597,514 , U.S. Patent 5,326,529 and CA
125 843 describe the use of migratable corrosion inhibitors in reinforced concrete and reinforced cements.
Also well known in the art is the use of low viscosity aqueous solutions of corrosion inhibitors for treating reinforced concrete surfaces. They are used especially in the market of the United States of America as well as in some European countries in the form of solutions of water-dilutable corrosion inhibitors and water as the diluting agent.
As is essentially the case in the use of waterproofing silanes, it is necessary for a successful protection of the reinforced concrete structure that a minimum quantity of inhibitors can penetrate into the surface of the structure;
because of their tendency to evaporate, particularly under summer-like conditions, this is hardly possible by using the above-mentioned low viscosity solutions. These difficulties occur especially when the solutions are used on essentially vertical surfaces and at the bottom side of a structure because the solution diluted with water is not spontaneously absorbed in the required quantity and several work steps are required for being able to work as much as possible without losses and in an economical manner.
Since a waterproofed surface is no longer capable of absorbing an aqueous inhibitor solution and, thus, an application in several work steps can also not be carried out, it would be conceivable, starting from the waterproofing cream according to the above-mentioned DE 196 28 035 A, to produce a combined waterproofing cream by working migratable corrosion inhibitors into a prepared gel-like protective substance. However, it has been found that the stable gel phase collapses because of the admixture of the corrosion inhibitor and that a phase separation of low viscosity liquids is the result.
SDENARY OF TAE INVENTION
Therefore, starting from the prior art discussed above, it is the primary object of the present invention to provide a process for producing a gel for the reduction and prevention of corrosion and corrosion progress on reinforcing steels in reinforced concrete structures which can be applied in a simple manner on a reinforced concrete structure.
In accordance with the present invention, the surface of the reinforced concrete structure is coated with a waterproofing and inhibiting gel which is prepared from waterproofing silanes or siloxanes and migratable corrosion inhibitors so as to form a gel-like, pasty mixture.
The preparation of a gel-like substance according to the present invention in which waterproofing silanes and siloxanes together with aqueous solutions of corrosion inhibitors result in a stable gel with the required properties makes it surprisingly possible to combine the high content of migratable inhibitors required for meeting the protective function and waterproofing silanes in a gel-like protective agent which remains stable and storable.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be had to the descriptive matter in which there are described preferred embodiments of the invention.
DESCRIPTION OF TH$ PREFERRED EMBODIMENTS
The protective agent according to the present invention can be applied in the form of a gel on the reinforced concrete structure which has been damaged by carbonization and corrosion.
Since it contains the following effective substances which are migratable into the building material, 1. waterproofing agent, 2. corrosion inhibitor 3. carrier substances, such as thickening agents 4. auxiliary substances, such as emulators, surface-active agents, pigments, the significant advantage of this gel-like protective agent is the fact that a single application of the protective agent on the damaged structure not only results in a sufficient waterproofing of the building stone matrix but also in a sufficient charging of the internal concrete structure with migratable corrosion inhibitors in order to protect the reinforcing steel against corrosion or to prevent a further corrosion progress.
Further details of the invention result from the following examples which have shown that gel-like protective agents having the compositions according to these examples on mortar disks or plates in accordance with TP OS, Section 5.5, have excellent penetration behaviors and the building material surface has significant hydrophobic properties.
Example 1 60% silane impregnating agent 30% 50% solution composed of dimethyl ethanolamine 10% additives/auxiliary agents Example 2 60% silane/siloxane impregnating agent 30% 50% solution composed of dimethyl ethanolamine and a-methyl aminobenzoate 10% additives/auxiliary agents This is evidenced by the following table:
Sample Initial Weight after Weight after Penetration No. weight [g] 2 days water 28 days water depth [mm]
storage storage A 356 358 362 5.4 B 362 364 368 8.5 C 367 370 373 9.6 D 369 371 375 6.4 E 365 367 371 6.1 It has also been found that the afore-mentioned mixtures according to examples 1 and 2 applied on concrete B II with a minimum cement content of 300 kg/m' CEM I 32.5 R and a water/cement value of 0.6 resulted in a surprising extension of the protection of reinforcing steels mounted in concrete. Even solutions containing significant amounts of chloride resulted in extensions of the lives of the steels by a factor of 5 - 8 if the test is carried out in accordance with Standard ASTM G 109 in a 30% sodium chloride solution. It has further been found that the rates of corrosion of repaired reinforced concrete surfaces over a test period of 3.5 years are significantly lower than in test areas which have been manufactured without the protective agents according to examples 1 and 2.
A gel-like protective agent in accordance with the following example can also be used with the same success Example 3 60% silane/siloxane impregnating agent 30% 50% solution composed of sodium monofluorophosphate 10% additives/auxiliary agents The invention is not limited by the embodiments described above which are presented as examples only but can be modified in various ways within the scope of protection defined by the appended patent claims.
For example, U.S. Patent No. 4,092,109 describes the use of calcium nitrite as a corrosion inhibitor in reinforced concrete.
Thus far, no process has become known which could be easily manipulated for protecting reinforced concrete surfaces in a practical and pexzcianent manner against the penetration of water and simultaneously for introducing migratable corrosion inhibitors into the existing concrete structure.
Concrete structures which contain corroded reinforcing steels are up to now repaired by mechanically removing the concrete Which is endangered by carbonization or corrosion or has been damaged by chloride; the rust is removed from the reinforcing steels by means of sand blasting methods and the steels are protected by a coat of corrosion protection paint. The subsequent reconstruction of the open concrete structure usually takes place by means of suitable concrete replacement materials (mortars) on the basis of mineral and organic binding agents. The state of the art in this connection can be found in the applicable Standards ZTV-SiB-PCC/SPCC and Rilli-DASTB.
The procedure described above of removing the damaged concrete substance and the subsequent reconstruction by means of corrosion protection paint, adhesive bridge, repair mortar and possibly surface protection paints is cumbersome and expensive.
Added to the significant costs of the repair of damaged reinforced steel structures as described above must be the fact that frequently the desired optical appearance of the original concrete facade is significantly altered by the repaired areas.
All of these aspects have in the past always led to the demand for a repair measure which makes it possible to repair concrete facades without the disadvantages described above.
At this point it must be mentioned that it is known in the art to prevent the penetration of water into the reinforced concrete structure by suitable coatings on the basis of silanes/siloxanes, polymer dispersions and solutions as well as reaction resin coatings, wherein the impregnation with silanes is of particular importance specifically for waterproofing the surfaces of exposed concrete facades.
Suitable compositions of such waterproofing or hydrophobic agents can be found in various patent publications. For example, EP 0 273 867, EP 0 518 324, EP 0 049 365, EP 0 101 816, EP 0 304 497 arid BP 0 385 108 discuss silicon-organic compositions which are used as waterproofing and impregnating solutions of building materials. 8P 0 177 824 already describes a resin-like organopolysiloxane impregnation for the surfaces of structural components, wherein additionally lamellar lattice silicates are added for improving the suitability for use, and wherein the formula contains solvents. PCT/SE95/00287 also discloses the composition of a paste-like hydrophobing or waterproofing agent which is provided with the desired processing consistency by means of a stratified silicate thickener. DE 196 28 035 A for the first time describes an aqueous cream of organosilicon components for waterproofing building materials which are absorbed by the building material without residue.
Corrosion inhibitors are used today especially in the market of the United States of America, but also in some European countries, as an admixture to fresh concrete. For example, EP 0 635 463 describes the use of an admixture for preventing the corrosion in building materials, and CH 686 386 describes the use of corrosion inhibiting amine components as a conversion product with acids for the same use. Moreover, U.S. Patent No. 5,750,053, EP 787 .697, U.S. Patent 5,597,514 , U.S. Patent 5,326,529 and CA
125 843 describe the use of migratable corrosion inhibitors in reinforced concrete and reinforced cements.
Also well known in the art is the use of low viscosity aqueous solutions of corrosion inhibitors for treating reinforced concrete surfaces. They are used especially in the market of the United States of America as well as in some European countries in the form of solutions of water-dilutable corrosion inhibitors and water as the diluting agent.
As is essentially the case in the use of waterproofing silanes, it is necessary for a successful protection of the reinforced concrete structure that a minimum quantity of inhibitors can penetrate into the surface of the structure;
because of their tendency to evaporate, particularly under summer-like conditions, this is hardly possible by using the above-mentioned low viscosity solutions. These difficulties occur especially when the solutions are used on essentially vertical surfaces and at the bottom side of a structure because the solution diluted with water is not spontaneously absorbed in the required quantity and several work steps are required for being able to work as much as possible without losses and in an economical manner.
Since a waterproofed surface is no longer capable of absorbing an aqueous inhibitor solution and, thus, an application in several work steps can also not be carried out, it would be conceivable, starting from the waterproofing cream according to the above-mentioned DE 196 28 035 A, to produce a combined waterproofing cream by working migratable corrosion inhibitors into a prepared gel-like protective substance. However, it has been found that the stable gel phase collapses because of the admixture of the corrosion inhibitor and that a phase separation of low viscosity liquids is the result.
SDENARY OF TAE INVENTION
Therefore, starting from the prior art discussed above, it is the primary object of the present invention to provide a process for producing a gel for the reduction and prevention of corrosion and corrosion progress on reinforcing steels in reinforced concrete structures which can be applied in a simple manner on a reinforced concrete structure.
In accordance with the present invention, the surface of the reinforced concrete structure is coated with a waterproofing and inhibiting gel which is prepared from waterproofing silanes or siloxanes and migratable corrosion inhibitors so as to form a gel-like, pasty mixture.
The preparation of a gel-like substance according to the present invention in which waterproofing silanes and siloxanes together with aqueous solutions of corrosion inhibitors result in a stable gel with the required properties makes it surprisingly possible to combine the high content of migratable inhibitors required for meeting the protective function and waterproofing silanes in a gel-like protective agent which remains stable and storable.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be had to the descriptive matter in which there are described preferred embodiments of the invention.
DESCRIPTION OF TH$ PREFERRED EMBODIMENTS
The protective agent according to the present invention can be applied in the form of a gel on the reinforced concrete structure which has been damaged by carbonization and corrosion.
Since it contains the following effective substances which are migratable into the building material, 1. waterproofing agent, 2. corrosion inhibitor 3. carrier substances, such as thickening agents 4. auxiliary substances, such as emulators, surface-active agents, pigments, the significant advantage of this gel-like protective agent is the fact that a single application of the protective agent on the damaged structure not only results in a sufficient waterproofing of the building stone matrix but also in a sufficient charging of the internal concrete structure with migratable corrosion inhibitors in order to protect the reinforcing steel against corrosion or to prevent a further corrosion progress.
Further details of the invention result from the following examples which have shown that gel-like protective agents having the compositions according to these examples on mortar disks or plates in accordance with TP OS, Section 5.5, have excellent penetration behaviors and the building material surface has significant hydrophobic properties.
Example 1 60% silane impregnating agent 30% 50% solution composed of dimethyl ethanolamine 10% additives/auxiliary agents Example 2 60% silane/siloxane impregnating agent 30% 50% solution composed of dimethyl ethanolamine and a-methyl aminobenzoate 10% additives/auxiliary agents This is evidenced by the following table:
Sample Initial Weight after Weight after Penetration No. weight [g] 2 days water 28 days water depth [mm]
storage storage A 356 358 362 5.4 B 362 364 368 8.5 C 367 370 373 9.6 D 369 371 375 6.4 E 365 367 371 6.1 It has also been found that the afore-mentioned mixtures according to examples 1 and 2 applied on concrete B II with a minimum cement content of 300 kg/m' CEM I 32.5 R and a water/cement value of 0.6 resulted in a surprising extension of the protection of reinforcing steels mounted in concrete. Even solutions containing significant amounts of chloride resulted in extensions of the lives of the steels by a factor of 5 - 8 if the test is carried out in accordance with Standard ASTM G 109 in a 30% sodium chloride solution. It has further been found that the rates of corrosion of repaired reinforced concrete surfaces over a test period of 3.5 years are significantly lower than in test areas which have been manufactured without the protective agents according to examples 1 and 2.
A gel-like protective agent in accordance with the following example can also be used with the same success Example 3 60% silane/siloxane impregnating agent 30% 50% solution composed of sodium monofluorophosphate 10% additives/auxiliary agents The invention is not limited by the embodiments described above which are presented as examples only but can be modified in various ways within the scope of protection defined by the appended patent claims.
Claims (6)
1. A process for reducing and preventing corrosion and corrosion progress of reinforcing steels in reinforced concrete structures, the process comprising coating a reinforced concrete structure surface with a waterproofing and inhibiting gel prepared from an aqueous solution of corrosion inhibitors and waterproofing silanes or siloxanes in the form of a stable gel-like emulsion.
2. The process according to claim 1, comprising adding thickening agents to the emulsion.
3. The process according to claim 1, comprising preparing the gel-like emulsion with the use of amino alcohols as migratable inhibitors forming an initial substance of the gel-like emulsion.
4. The process according to claim 1, comprising preparing the gel-like emulsion with the use of fluorophosphates as migratable inhibitors forming an initial substance of the gel-like emulsion.
5. The process according to claim 1, comprising adding a solvent as a diluting agent to the gel-like emulsion.
6. The process according to claim 1, further comprising using the emulsion as a foundation for additional layers.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE1999111135 DE19911135A1 (en) | 1999-03-12 | 1999-03-12 | Concrete reinforcing steel is protected against corrosion by coating the concrete with a gel mixture of corrosion inhibitor and water-proofing silane and/or siloxane |
| DE19911135.9 | 1999-03-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2300614A1 true CA2300614A1 (en) | 2000-09-12 |
Family
ID=7900794
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2300614 Abandoned CA2300614A1 (en) | 1999-03-12 | 2000-03-10 | Process for reducing and preventing corrosion and corrosion progress on reinforcing steels of reinforced concrete structures |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2300614A1 (en) |
| DE (1) | DE19911135A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6685766B2 (en) | 2001-11-05 | 2004-02-03 | Degussa Ag | Corrosion inhibitor for steel-reinforced concrete |
| WO2014032167A1 (en) * | 2012-08-29 | 2014-03-06 | Protocol Environmental Solutions, Inc. | Gypsum remover |
| WO2022000305A1 (en) * | 2020-06-29 | 2022-01-06 | 江苏苏博特新材料股份有限公司 | Organic silicon nanoprecursor medium transmission inhibitor, preparation method therefor and use thereof |
| WO2024013263A1 (en) * | 2022-07-12 | 2024-01-18 | Holcim Technology Ltd | Method of reduction corrosion of reinforced carbonated construction elements |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001090022A1 (en) * | 2000-05-24 | 2001-11-29 | Martin Baeuml | Cement-bound active substance |
-
1999
- 1999-03-12 DE DE1999111135 patent/DE19911135A1/en not_active Withdrawn
-
2000
- 2000-03-10 CA CA 2300614 patent/CA2300614A1/en not_active Abandoned
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6685766B2 (en) | 2001-11-05 | 2004-02-03 | Degussa Ag | Corrosion inhibitor for steel-reinforced concrete |
| WO2014032167A1 (en) * | 2012-08-29 | 2014-03-06 | Protocol Environmental Solutions, Inc. | Gypsum remover |
| US10584073B2 (en) | 2012-08-29 | 2020-03-10 | Protocol Environmental Solutions Inc. | Gypsum remover |
| WO2022000305A1 (en) * | 2020-06-29 | 2022-01-06 | 江苏苏博特新材料股份有限公司 | Organic silicon nanoprecursor medium transmission inhibitor, preparation method therefor and use thereof |
| WO2024013263A1 (en) * | 2022-07-12 | 2024-01-18 | Holcim Technology Ltd | Method of reduction corrosion of reinforced carbonated construction elements |
Also Published As
| Publication number | Publication date |
|---|---|
| DE19911135A1 (en) | 2000-09-14 |
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