阅读说明：本技术 存在于具有暴露于氯化物侵入的一个或多个表面的硬化混凝土结构中的金属增强体的腐蚀抑制 (Corrosion inhibition of metal reinforcement present in hardened concrete structures having one or more surfaces exposed to chloride intrusion ) 是由 朱塞佩·希历弗 沃尔弗拉姆·弗兰克 尼考劳斯·N·斯塔夫罗莱基斯 于 2020-04-03 设计创作，主要内容包括：本公开涉及用于存在于具有暴露于氯化物侵入的一个或多个表面的硬化混凝土结构中的金属增强体的腐蚀抑制以及任选的恢复的方法,该方法包括将碱金属硝酸盐水溶液、碱土金属硝酸盐水溶液、硝酸锌水溶液、硝酸铝水溶液、硝酸铵水溶液或其混合物施用在一个或多个所述表面上的步骤。本公开还涉及碱金属硝酸盐水溶液、碱土金属硝酸盐水溶液、硝酸锌水溶液、硝酸铝水溶液、硝酸铵水溶液或其混合物通过被施用在包括暴露于氯化物侵入的金属增强体的硬化混凝土结构的一个或多个表面上而作为腐蚀抑制剂的用途。本公开还涉及用于抑制存在于硬化混凝土结构中的金属增强体的腐蚀的腐蚀抑制性组合物,该硬化混凝土结构具有暴露于氯化物侵入的一个或多个表面。(The present disclosure relates to a method for corrosion inhibition and optionally restoration of a metal reinforcement present in a hardened concrete structure having one or more surfaces exposed to chloride intrusion, the method comprising the step of applying an aqueous alkali metal nitrate solution, an aqueous alkaline earth metal nitrate solution, an aqueous zinc nitrate solution, an aqueous aluminum nitrate solution, an aqueous ammonium nitrate solution or mixtures thereof on one or more of said surfaces. The present disclosure also relates to the use of an aqueous alkali metal nitrate solution, an aqueous alkaline earth metal nitrate solution, an aqueous zinc nitrate solution, an aqueous aluminum nitrate solution, an aqueous ammonium nitrate solution, or mixtures thereof as a corrosion inhibitor by being applied on one or more surfaces of a hardened concrete structure comprising a metal reinforcement exposed to chloride intrusion. The present disclosure also relates to corrosion inhibiting compositions for inhibiting corrosion of metal reinforcement present in hardened concrete structures having one or more surfaces exposed to chloride intrusion.)

1. A method for corrosion inhibition of a metal reinforcement present in a hardened concrete structure having one or more surfaces exposed to chloride intrusion, wherein the method comprises the step of applying an aqueous alkali metal nitrate solution, an aqueous alkaline earth metal nitrate solution, an aqueous zinc nitrate solution, an aqueous aluminum nitrate solution, an aqueous ammonium nitrate solution, or a mixture thereof, on one or more of the surfaces, wherein the aqueous nitrate solution further comprises an organic solvent selected from the group consisting of: glycol ethers, including ethylene substituted monoethyl glycol ether, ethylene substituted monomethyl glycol ether, ethylene substituted monopropyl glycol ether, and ethylene substituted monobutyl glycol ether, more particularly ethylene glycol monobutyl ether.

2. The method of claim 1, wherein an aqueous solution of calcium nitrate comprising 10 to 20 wt.%, more particularly 15 to 20 wt.%, and most particularly 15 wt.% of calcium nitrate dissolved in deionized water is applied on one or more of the surfaces.

3. The method of claim 1 or 2, wherein the aqueous solution further comprises from 0.1 to 5.0 wt.%, more particularly from 0.5 to 3.0 wt.% of a penetration enhancer selected from the group consisting of:

ethoxylated linear alcohols, more particularly ethoxylated fatty alcohols with a degree of ethoxylation of more than 10, and more particularly tridecyl alcohol ethoxylates,

ethoxylated octylphenol, ethoxylated nonylphenol and ethoxylated dodecylphenol having a degree of ethoxylation ranging from 12 to 20,

-a secondary alcohol ethoxylate,

ethoxylated mercaptans with a degree of ethoxylation in the range of from 8 to 10, in particular tert-dodecyl mercaptan,

-mono-and diglycerides,

acetylenic alcohols and acetylenic diols, and alkoxylated acetylenic alcohols and acetylenic diols,

-N- (alkoxycarbonyl) alanine, more particularly N-octylalanine, N-dodecylalanine, N-hexadecylalanine and/or N-octadecylalanine,

-N-alkylated pyrrolidones, more particularly 1- (C8-C12-alkyl) -2-pyrrolidones, more particularly 1-octyl-2-pyrrolidone, 1-dodecyl-2-pyrrolidone,

-alkyl esters of sulfosuccinic acid, more particularly C14-C18 diesters of sulfosuccinic acid,

-N-acyl sarcosinates, more particularly N-oleoyl sarcosinate, N-lauroyl sarcosinate, N-myristoyl sarcosinate and/or N-cocoyl sarcosinate, and/or their sodium salts.

4. The method according to any one of claims 1 to 3, wherein the aqueous solution comprises from 0.1 to 5.0 wt. -%, more particularly from 1.0 to 2.0 wt. -% of an organic solvent selected from the group consisting of: glycol ethers, including ethylene substituted monoethyl glycol ether, ethylene substituted monomethyl glycol ether, ethylene substituted monopropyl glycol ether, and ethylene substituted monobutyl glycol ether, more particularly ethylene glycol monobutyl ether.

5. Use of an aqueous alkali metal nitrate solution, an aqueous alkaline earth metal nitrate solution, an aqueous zinc nitrate solution, an aqueous aluminum nitrate solution, an aqueous ammonium nitrate solution or mixtures thereof as a corrosion inhibitor by applying it on one or more surfaces of a hardened concrete structure comprising a metal reinforcement exposed to chloride intrusion, wherein the aqueous nitrate solution further comprises an organic solvent selected from the group consisting of: glycol ethers, including ethylene substituted monoethyl glycol ether, ethylene substituted monomethyl glycol ether, ethylene substituted monopropyl glycol ether, and ethylene substituted monobutyl glycol ether, more particularly ethylene glycol monobutyl ether.

6. Use according to claim 5, wherein an aqueous calcium nitrate solution is applied, comprising 10 to 20 wt.%, more particularly 15 to 20 wt.%, and most particularly 15 wt.% of calcium nitrate dissolved in deionized water.

7. Use according to claim 5 or 6, wherein the aqueous solution comprises from 0.1 to 5.0 wt.%, more particularly from 0.5 to 3.0 wt.% of a penetration enhancer selected from the group consisting of:

ethoxylated linear alcohols, more particularly ethoxylated fatty alcohols with a degree of ethoxylation of more than 10, and more particularly tridecyl alcohol ethoxylates,

ethoxylated octylphenol, ethoxylated nonylphenol and ethoxylated dodecylphenol having a degree of ethoxylation ranging from 12 to 20,

-a secondary alcohol ethoxylate,

ethoxylated mercaptans with a degree of ethoxylation in the range of from 8 to 10, in particular tert-dodecyl mercaptan,

-mono-and diglycerides,

acetylenic alcohols and acetylenic diols, and alkoxylated acetylenic alcohols and acetylenic diols,

-N- (alkoxycarbonyl) alanine, more particularly N-octylalanine, N-dodecylalanine, N-hexadecylalanine and/or N-octadecylalanine,

-N-alkylated pyrrolidones, more particularly 1- (C8-C12-alkyl) -2-pyrrolidones, more particularly 1-octyl-2-pyrrolidone, 1-dodecyl-2-pyrrolidone,

-alkyl esters of sulfosuccinic acid, more particularly C14-C18 diesters of sulfosuccinic acid,

-N-acyl sarcosinates, more particularly N-oleoyl sarcosinate, N-lauroyl sarcosinate, N-myristoyl sarcosinate and/or N-cocoyl sarcosinate, and/or their sodium salts.

8. Use according to any one of claims 5 to 7, wherein the aqueous solution further comprises from 0.1 to 5.0% by weight, more particularly from 1.0 to 2.0% by weight of an organic solvent selected from the group consisting of: glycol ethers, including ethylene substituted monoethyl glycol ether, ethylene substituted monomethyl glycol ether, ethylene substituted monopropyl glycol ether, and ethylene substituted monobutyl glycol ether, more particularly ethylene glycol monobutyl ether.

9. A corrosion inhibiting composition for inhibiting corrosion of a metal reinforcement present in a hardened concrete structure having one or more surfaces exposed to chloride intrusion, comprising

10 to 20% by weight, more particularly 15 to 20% by weight, and most particularly 15% by weight of calcium nitrate dissolved in deionized water;

-0.1 to 5.0 wt.%, more particularly 0.5 to 3.0 wt.% of a penetration enhancer selected from the group consisting of:

ethoxylated linear alcohols, more particularly ethoxylated fatty alcohols with a degree of ethoxylation of more than 10, and more particularly tridecyl alcohol ethoxylates,

ethoxylated octylphenols, ethoxylated nonylphenols and ethoxylated dodecylphenols having a degree of ethoxylation in the range from 12 to 20,

a secondary alcohol ethoxylate, in particular a fatty alcohol ethoxylate,

ethoxylated mercaptans with a degree of ethoxylation in the range of from 8 to 10, in particular tert-dodecyl mercaptan,

mono-and diglycerides, in the presence of water,

acetylenic alcohols and acetylenic diols,

alkoxylated acetylenic alcohols and acetylenic diols,

n- (alkoxycarbonyl) alanine, more particularly N-octylalanine, N-dodecylalanine, N-hexadecylalanine and/or N-octadecylalanine,

n-alkylated pyrrolidones, more particularly 1- (C8-C12-alkyl) -2-pyrrolidones, more particularly 1-octyl-2-pyrrolidone, 1-dodecyl-2-pyrrolidone,

alkyl esters of sulfosuccinic acid, more particularly C14-C18 diesters of sulfosuccinic acid,

n-acyl sarcosinates, more particularly N-oleoyl sarcosinate, N-lauroyl sarcosinate, N-myristoyl sarcosinate and/or N-cocoyl sarcosinate, and/or their sodium salts, and

0.1 to 5.0 wt.%, more particularly 1.0 to 2.0 wt.% of an organic solvent selected from the group consisting of: glycol ethers, including ethylene substituted monoethyl glycol ether, ethylene substituted monomethyl glycol ether, ethylene substituted monopropyl glycol ether, and ethylene substituted monobutyl glycol ether, more particularly ethylene glycol monobutyl ether.

Technical Field

The present disclosure relates to corrosion inhibition of metal reinforcement present in hardened (also referred to as set) concrete structures such as buildings, bridges, roads, and the like (hereinafter "reinforced concrete structures") having one or more surfaces exposed to chloride intrusion, including corrosion of the metal reinforcement. A corrosion inhibitor is defined as a "substance or mixture that inhibits, prevents, or minimizes corrosion at a concentration and in an aggressive environment.

Background

Concrete structures such as buildings, bridges, roads, etc. for structural purposes are made of hardened concrete and usually have a metal reinforcement in their core to reinforce the hardened concrete and keep the set concrete under compression. Concrete is strong under compression but has a weak tensile strength. The most common forms of these metal reinforcements are steel bars (rebars), short for steel bars, and wire mesh. Other types of metal reinforcement are meshes, girders, channel beams, etc. The metal may be in the form of iron and steel. The reinforcing steel bar remarkably improves the tensile strength of the concrete structure.

Chloride attack poses a significant threat to reinforced concrete structures, especially structures in marine environments or structures that may be exposed to high concentrations of salts. The net result of chloride attack is corrosion of the metal reinforcement, which leads to cracking and spalling of the concrete structure, and in some cases catastrophic structural failure because the load bearing capacity of the concrete is compromised.

The attack mode originates from salts and other corrosive substances carried by the moisture, absorbed into the concrete by capillary action via its pores and micropores. Once absorbed, these substances act to lower the pH of the concrete, thereby eliminating its passivating oxide layer which would otherwise provide protection to the rebar. Corrosion occurs as chloride ions encounter steel and surrounding passivating material to create a chemical process that forms hydrochloric acid. Hydrochloric acid attacks the rebar.

During winter, the concrete of bridges, highways, parking lots, sidewalks, etc. is exposed to salts, such as calcium chloride and sodium chloride, which are used to counteract the undesired accumulation of snow and ice. Although these chloride salts are beneficial in deicing the concrete surface of such reinforced concrete structures, they most often cause migration of the formed chloride solution into the exposed surfaces thereof. The exposed surfaces may be horizontal as well as vertical (such as walls and posts). In addition, salt-containing seawater in contact with the reinforced concrete structure may intrude into the concrete pores.

One known method for corrosion inhibition of metal reinforcement present inside concrete structures is the application of calcium nitrite.

For example, in US 6,810,634, a method of using calcium nitrite to control corrosion in hydraulic cement containing metal masses or structures is disclosed. The method comprises introducing at least one compound capable of chelating chloride ions into fresh concrete containing a metallic element.

In US 4,605,572, a method for inhibiting corrosion of existing steel materials embedded in inorganic materials such as concrete is described. The method includes the step of applying an aqueous solution of an inorganic salt, such as calcium nitrite, to the surface of the inorganic material.

However, calcium nitrite has the disadvantage that it is toxic to the environment, as it can be washed away by rain, or invaded by water. Calcium nitrite is also toxic to the personnel handling it, thus causing health risks. A final disadvantage is that calcium nitrite is expensive to use.

The object of the present disclosure is to inhibit corrosion of concrete containing reinforcement by: one or more surfaces of the reinforced concrete structure exposed to chloride intrusion causing corrosion of the metal reinforcement are infiltrated with a liquid that is not harmful to the environment and the health of workers handling the liquid, and that is less costly to apply.

SUMMARY

According to a first aspect of the present disclosure, a method for corrosion inhibition of a metal reinforcement present in a hardened concrete structure is described, wherein the method comprises applying an aqueous alkali metal nitrate solution, an aqueous alkaline earth metal nitrate solution, an aqueous zinc nitrate solution, an aqueous ammonium nitrate solution, an aqueous aluminum nitrate solution, or a mixture thereof, on one or more surfaces of a reinforced concrete structure exposed to chloride intrusion. The aqueous solution does not contain calcium nitrite (Ca (NO)₂)₂)。

It has been surprisingly found that aqueous solutions of alkali metal nitrates or alkaline earth metal nitrates, which are less expensive and also non-toxic than the aqueous solutions of calcium nitrite used in the prior art, are corrosion-inhibiting for steel reinforcement embedded in hardened concrete structures.

It has also been found that the aqueous alkali metal nitrate solution or the aqueous alkaline earth metal nitrate solution penetrates from the surface of the hardened concrete structure to a sufficient depth of the concrete structure to reach the reinforcing steel bars and exert a corrosion inhibiting effect. In this manner, the corrosion inhibitor need only be applied to the surface area above the rebar, which requires less solution to be used than if the solution were applied to the concrete mix prior to hardening of the concrete mix.

It was also observed that this method according to the present disclosure leads to long-term results.

It is noted that an additional effect of applying a solution as described above is that there may be restoration of metallic reinforcement embedded in the hardened reinforced concrete structure that has corroded.

In one possible method according to the present disclosure, an aqueous solution of calcium nitrate comprising 10 to 20 wt.%, more particularly 15 to 20 wt.%, and most particularly about 15 wt.% of calcium nitrate dissolved in deionized water is applied to one or more surfaces.

In one optional method according to the present disclosure, the aqueous solution further comprises 0.1 to 5.0 wt.%, more particularly 0.5 to 3.0 wt.% of a penetration enhancer selected from the group consisting of:

ethoxylated linear alcohols, more particularly ethoxylated fatty alcohols with a degree of ethoxylation of more than 10, and more particularly tridecyl alcohol ethoxylates,

-ethoxylated octylphenols, nonylphenols and dodecylphenols having a degree of ethoxylation in the range from 12 to 20,

-a secondary alcohol ethoxylate,

ethoxylated mercaptans with a degree of ethoxylation in the range of from 8 to 10, in particular tert-dodecyl mercaptan,

-mono-and diglycerides,

acetylenic alcohols and acetylenic diols, and alkoxylated acetylenic alcohols and acetylenic diols,

-N- (alkoxycarbonyl) alanine, more particularly N-octylalanine, N-dodecylalanine, N-hexadecylalanine and/or N-octadecylalanine,

-N-alkylated pyrrolidones, more particularly 1- (C8-C12-alkyl) -2-pyrrolidones, more particularly 1-octyl-2-pyrrolidone, 1-dodecyl-2-pyrrolidone,

-alkyl esters of sulfosuccinic acid, more particularly C14-C18 diesters of sulfosuccinic acid,

-N-acyl sarcosinates, more particularly N-oleoyl sarcosinate, N-lauroyl sarcosinate, N-myristoyl sarcosinate and/or N-cocoyl sarcosinate, and/or their sodium salts.

Such surfactants, when applied in a continuous coating on the surface of a hardened concrete structure having metallic reinforcement that undergoes corrosion or is susceptible to corrosion, provide enhanced wetting and penetration capabilities by altering the surface tension of the composition.

In one optional method according to the present disclosure, the aqueous solution further comprises 0.1 to 5.0 wt.%, more particularly 1.0 to 2.0 wt.% of an organic solvent selected from the group consisting of: glycol ethers, including ethylene substituted monoethyl glycol ethers, monomethyl glycol ethers, monopropyl glycol ethers and monobutyl glycol ethers, more particularly ethylene glycol monobutyl ether.

The glycol ether provides good long term stability and shelf life of the aqueous solution, as contemplated herein, and improves the wetting properties of the aqueous-based solution, as contemplated herein.

According to another aspect of the present disclosure, the use of an aqueous alkali metal nitrate solution, an aqueous alkaline earth metal nitrate solution, an aqueous zinc nitrate solution, an aqueous aluminum nitrate solution, an aqueous ammonium nitrate solution, or mixtures thereof as a corrosion inhibitor by applying it on one or more surfaces of a hardened concrete structure comprising a metal reinforcement exposed to chloride intrusion is described.

In one possible use according to the present disclosure, an aqueous solution of calcium nitrate is applied to the surface of a hardened reinforced concrete structure. The aqueous calcium nitrate solution specifically comprises 10 to 20 wt.%, more specifically 15 to 20 wt.%, and most specifically about 15 wt.% calcium nitrate dissolved in deionized water.

In one particular use according to the present disclosure, the aqueous solution comprises from 0.1 to 5.0 wt.%, more particularly from 0.5 to 3.0 wt.% of a penetration enhancer selected from the group consisting of:

ethoxylated linear alcohols, more particularly ethoxylated fatty alcohols with a degree of ethoxylation of more than 10, and more particularly tridecyl alcohol ethoxylates,

-ethoxylated octylphenols, nonylphenols and dodecylphenols having a degree of ethoxylation in the range from 12 to 20,

-a secondary alcohol ethoxylate,

ethoxylated mercaptans with a degree of ethoxylation in the range of from 8 to 10, in particular tert-dodecyl mercaptan,

-mono-and diglycerides,

acetylenic alcohols and acetylenic diols, and alkoxylated acetylenic alcohols and acetylenic diols,

-N- (alkoxycarbonyl) alanine, more particularly N-octylalanine, N-dodecylalanine, N-hexadecylalanine and/or N-octadecylalanine,

-N-alkylated pyrrolidones, more particularly 1- (C8-C12-alkyl) -2-pyrrolidones, more particularly 1-octyl-2-pyrrolidone, 1-dodecyl-2-pyrrolidone,

-alkyl esters of sulfosuccinic acid, more particularly C14-C18 diesters of sulfosuccinic acid,

-N-acyl sarcosinates, more particularly N-oleoyl sarcosinate, N-lauroyl sarcosinate, N-myristoyl sarcosinate and/or N-cocoyl sarcosinate, and/or their sodium salts.

In one possible use according to the present disclosure, the aqueous solution further comprises 0.1 to 5.0 wt. -%, more particularly 1.0 to 2.0 wt. -% of an organic solvent selected from the group consisting of: glycol ethers, including ethylene substituted monoethyl glycol ether, monomethyl glycol ether, monopropyl glycol ether, and monobutyl glycol ether. More particularly, ethylene glycol monobutyl ether is used.

In accordance with another aspect of the present disclosure, a corrosion-inhibiting composition for inhibiting corrosion of a metal reinforcement present in a hardened concrete structure having one or more surfaces exposed to chloride intrusion is described, the corrosion-inhibiting composition comprising

10 to 20% by weight, more particularly 15 to 20% by weight, and most particularly 15% by weight of calcium nitrate dissolved in deionized water;

-0.1 to 5.0 wt.%, more particularly 0.5 to 3.0 wt.% of a penetration enhancer selected from the group consisting of:

ethoxylated linear alcohols, more particularly ethoxylated fatty alcohols with a degree of ethoxylation of more than 10, and more particularly tridecyl alcohol ethoxylates,

ethoxylated octylphenols, nonylphenols and dodecylphenols having a degree of ethoxylation in the range from 12 to 20,

a secondary alcohol ethoxylate, in particular a fatty alcohol ethoxylate,

ethoxylated mercaptans with a degree of ethoxylation in the range of from 8 to 10, in particular tert-dodecyl mercaptan,

mono-and diglycerides, in the presence of water,

acetylenic alcohols and acetylenic diols,

alkoxylated acetylenic alcohols and acetylenic diols,

n- (alkoxycarbonyl) alanine, more particularly N-octylalanine, N-dodecylalanine, N-hexadecylalanine and/or N-octadecylalanine,

n-alkylated pyrrolidones, more particularly 1- (C8-C12-alkyl) -2-pyrrolidones, more particularly 1-octyl-2-pyrrolidone, 1-dodecyl-2-pyrrolidone,

alkyl esters of sulfosuccinic acid, more particularly C14-C18 diesters of sulfosuccinic acid,

n-acyl sarcosinates, more particularly N-oleoyl sarcosinate, N-lauroyl sarcosinate, N-myristoyl sarcosinate and/or N-cocoyl sarcosinate, and/or their sodium salts, and

-0.1 to 5.0 wt.%, more particularly 1.0 to 2.0 wt.% of an organic solvent selected from the group consisting of: glycol ethers, including ethylene substituted monoethyl glycol ethers, monomethyl glycol ethers, monopropyl glycol ethers and monobutyl glycol ethers, more particularly ethylene glycol monobutyl ether.