CN116081976A - High-performance concrete anti-corrosion reinforcing agent, preparation method and application - Google Patents

Abstract

The invention discloses a high-performance concrete anti-corrosion reinforcing agent, a preparation method and application thereof, and belongs to the field of concrete additives. The high-performance concrete anti-corrosion reinforcing agent consists of a modified nano material with a filling effect, alkanolamine and a hydroxyl compound; the modified nano material is a nano material with the surface treated by an organic modifier; the organic modifier is organic siloxane or organic carboxylic acid or a combination of the two. The organic siloxane is connected with the nano material through silanol bonds, and the organic carboxylic acid is physically adsorbed on the surface of the nano material. The modification nano material and the alcohol amine hydration regulation material are combined to optimize and promote the microstructure of the concrete, so that the pore compactness of the concrete can be effectively optimized and improved, the corrosion resistance, the freezing resistance and the carbonization resistance of the concrete are realized, and the durability of the concrete is realized.

Description

High-performance concrete anti-corrosion reinforcing agent, preparation method and application

Technical Field

The invention belongs to the field of concrete additives, and particularly relates to a high-performance concrete anti-corrosion reinforcing agent, a preparation method and application thereof.

Background

Reinforced concrete is widely used in infrastructure construction, but the long service life and high durability of the concrete are still a difficult problem which cannot be overcome, and the reinforced concrete is particularly more remarkable in the problems of poor sulfate corrosion resistance, poor freezing resistance, serious carbonization, shrinkage cracking and the like of the concrete in a severe service environment, so that immeasurable losses are brought to national economy and people's life and property safety. The improvement of the corrosion resistance of the concrete becomes an effective way for guaranteeing the service safety and the service life of important foundation engineering.

For sulfate corrosion of concrete, the improvement of the compactness of the concrete is considered to be more studied at present, and the main technical means comprise the reduction of the water-cement ratio and the use of mineral admixtures; reducing the water-cement ratio and the water consumption greatly influences the workability of the fresh concrete; the use of mineral admixtures such as fly ash, mineral powder and silica fume can cause lower early strength of concrete, exacerbate carbonization depth and increase risk of shrinkage cracking; the conventional technical means mainly reduces the number of pores and optimizes the pore structure to reduce the transmissible path of aggressive ions. However, in the practical environment, sulfate corrosion damage is continuously eroded from the surface of the concrete to the interior of the concrete, and the process of higher corrosion rate is self-cracking, pulverization and cementing property loss of a concrete cementing material system caused by sulfate crystallization damage. The simple improvement of the compactness of the concrete has a certain limitation in improving the sulfate and corrosion resistance of the concrete, and unless the water-cement ratio of the concrete is reduced to the maximum extent, the performance of the concrete reaches the performance level of the ultra-high-performance concrete, the sulfate and corrosion resistance of the concrete can be obviously improved, otherwise, the effect of improving and improving the corrosion resistance of the concrete is relatively weak for the concrete with middle and low strength in general by using the conventional compacting technology means. In recent years, with the continuous deep research, novel nano materials are continuously developed, and some nano suspensions are already applied to engineering practice, for example, patent CN105330194B reports that the nano suspensions can be used as early-stage compactness, strength improvement and corrosion resistance inhibition materials of concrete, but the nano materials have influence on the later-stage strength of the concrete, and the long-term corrosion resistance of the concrete is yet to be verified. Although there is also a patent report (CN 105601162 a) that some novel nano materials and hydrophobic organosilane and other combined materials can optimize and enhance the erosion resistance of concrete, the combined materials have poor dispersibility and excessively affect early performance, so that the long-term erosion resistance of the combined materials to concrete in practical application is still not significant enough, the improvement of the erosion resistance of concrete is mostly the hydrophobic organosilane itself enhances the medium permeation resistance of the concrete itself, but the long-term erosion resistance of the organosiloxane itself also needs time inspection.

In addition, the combination of components such as water reduction, compaction, crack resistance and rust resistance of the steel bars of some concrete is also a main direction of the development of the anti-corrosion reinforced products of the concrete. As reported in patent CN101475334a, a composite concrete preservative is composed of a combination of water-reducing and reinforcing components, a cathode-type steel bar rust-resisting component, air-entraining components, a compacting component and the like, wherein the components of water-reducing, reinforcing, compacting and the like are all common raw materials, and the main functions can be realized through concrete proportioning regulation and application of mineral admixture and the like. Patents US6340438, US5527388, US 006174461B 1, US 006342101B 1, CN 201210099558.0 report mixtures of inorganic salts and low molecular weight (alcohol) amines as concrete additives for corrosion inhibition of steel reinforcement in reinforced concrete structural systems, but the influence of such substances on the properties of the concrete itself, in particular on the corrosion resistance of the concrete, is less mentioned. On the basis of researching simple alcohol amine type reinforced bar corrosion inhibition materials (cement concrete composites,2004,26,199-207), nmaiCK provides a multifunctional reinforced concrete corrosion inhibitor, wherein lauroyl sarcosinic acid organic acid is used for structural modification to prepare an anti-corrosion concrete additive with the functions of resisting sulfate corrosion of concrete and inhibiting reinforced bar corrosion, the specific action mechanism is still not clear, and the main anti-corrosion effect is presumed to be that hydrophobic substances are generated by the reaction of lauroyl sarcosine and calcium ions in the concrete to inhibit the corrosion of the concrete. However, lauroyl sarcosinic acid substances have strong surface activity in practical application, and under the condition of achieving an anti-corrosion effect, the mixing amount is generally higher, so that more bubbles are easily introduced into a concrete system, the compactness of the concrete is poor, and the long-term corrosion resistance of the concrete is at risk of deterioration.

Disclosure of Invention

The reinforced concrete has the common problems of poor sulfate corrosion resistance, poor freezing resistance and serious carbonization for the concrete in a severe service environment, and the durability of the concrete is more difficult to ensure in the environment; improving the compactness of the concrete and adding an anti-erosion inhibitor into the concrete are effective methods for improving and improving the durability of the concrete, but the effect of improving and improving the corrosion resistance of the concrete by the conventional compacting technology is relatively weak, and the durability of the anti-erosion inhibitor to the concrete in the prior art cannot be ensured. Aiming at the problems, the invention provides the high-performance concrete anti-corrosion reinforcing agent, and the combination of the modified nano material and the alcohol amine hydration regulation material can optimize and promote the microstructure of the concrete, effectively optimize and improve the pore compactness of the concrete, realize the corrosion resistance, the freezing resistance and the carbonization resistance of the concrete and achieve the durability of the concrete.

The high-performance concrete anti-corrosion reinforcing agent consists of a modified nano material with a filling effect, alkanolamine and a hydroxyl compound, wherein the components comprise the following components in percentage by mass:

modified nanomaterial: 4 to 50 percent of

Alkyl alcohol amine: 2 to 20 percent

Polyhydroxy compound: 0.01 to 5 percent

Water: allowance of

The sum of the mass percentages of the components is 100 percent.

Further preferably, the mass percentage of the modified nano material is 4% -8%, the mass percentage of the alkanolamine is 6% -12%, and the mass percentage of the polyhydroxy compound is 0.1% -3%. Preferably, the composition and the proportion of each material are comprehensively considered in consideration of the utilization rate of the modified material, the application cost and the like, and are optimized according to the compact filling performance and the modification effect.

The modified nano material is a nano material with the surface treated by an organic modifier; the organic modifier is organic siloxane or organic carboxylic acid or a combination of the two. The organic siloxane is connected with the nano material through silanol bonds, and the organic carboxylic acid is physically adsorbed on the surface of the nano material.

The mass ratio of the organic modifier to the nano material is 1:1-300.

The nanometer material is one or a combination of more of nanometer silicon dioxide, nanometer aluminum oxide and nanometer copper oxide, and the grain diameter range of the nanometer material is 5-1000nm.

The organic carboxylic acid is fatty acid or aromatic carboxylic acid with 1-20 carbon atoms;

the organic siloxane is methoxy or ethoxy siloxane with 1-20 carbon atoms.

The modification of the organic carboxylic acid to the surface of the nano material is mainly changed in a physical adsorption mode, and the organic siloxane can react with hydroxyl groups on the surface of the nano material through silanol bonds to generate firm chemical bonds, so that the effects of physical adsorption and chemical bonding are achieved. Physical adsorption and chemical bonding can better regulate and control the active release time of the nano material, and the physical property of the surface of the nano material is changed after the nano material is modified by organic acid or siloxane, so that certain hydrophobicity is generated on the surface; meanwhile, the organic acid or siloxane is covered, and a monolayer-like protective film is formed on the surface of the nano material, so that the activity of the nano material is inhibited to a certain extent, and the effects of compacting the pores of the nano material at the later stage and improving the long-term corrosion resistance of the concrete are truly exerted.

The coverage and compactness of the surface adsorption layer can be improved through the regulation and control of the molecular structure of the organic carboxylic acid or the organic siloxane, so that the expected modification effect is achieved, different nano materials with improved hydrophobic performance can be realized through the regulation of the chain length of the alkyl or aryl molecules, and the difference of the effects of improving the hydrophobic performance can cause the microstructure and the corrosion resistance of hydration products to change, so that the targeted corrosion resistance requirement can be realized.

Further, the organosiloxane is methoxy or ethoxy siloxane with 4-12 carbon atoms, and the structure adsorption arrangement sequence and the density can be adjusted through the regulation of the chain length of molecules, so that the regulation of the release rate of the nano particles is realized.

The alkyl alcohol amine is one or more of ethanolamine, diethanolamine, triethanolamine, dimethylethanolamine, N-methylethanolamine, N-methyldiethanolamine, ethylene glycol monoisopropanolamine, triisopropanolamine and N, N, N, N-tetrahydroxyethyl ethylenediamine.

The alkyl alcohol ammonia compound can regulate and control the hydration performance of cement, and is combined with the nano material, so that the filling and compacting effectiveness of the nano material in the process of compacting the concrete pores can be better realized. The alkanolamine compound and the nano modified material act together to realize the further regulation and improvement of the later hydration process of cement.

The polyhydroxy compound is one or a combination of more of cellulose ether, polyvinyl alcohol, cyclodextrin, chitosan, xanthan gum and varen gum. The molecular weight of the cellulose ether is 10 ten thousand to 1000 ten thousand. The molecular weight of the polyvinyl alcohol is 5 ten thousand to 1000 ten thousand. The cyclodextrin is alpha, beta or gamma cyclodextrin. The chitosan has a molecular weight of 10-1000 ten thousand. The xanthan gum or the valency gum is a common biological gum in the market.

The invention also provides a preparation method of the high-performance concrete anti-corrosion reinforcing agent, which comprises the following steps:

(1) Acidizing the nano material, adding an organic modifier, atomizing and mixing at 60-300 ℃, and uniformly mixing the nano material and the organic modifier to obtain the modified nano material;

(2) Adding water, alkanolamine and polyhydroxy compound into a reaction kettle, uniformly mixing, adding the modified nanomaterial in the step (1), controlling the pH value in the solution to be 5-9, and obtaining the high-performance concrete anti-corrosion reinforcing agent after the system is stable.

The acid which is acidized in the step (1) is one of hydrochloric acid, nitric acid and phosphoric acid.

The application of the high-performance anti-corrosion reinforcing agent is different from that of a general preservative, and the high-performance anti-corrosion reinforcing agent is a nano material water dispersion system, wherein the nano material water dispersion system is convenient to apply, dust pollution is avoided in the production and application processes, and meanwhile, the water dispersion system improves the dispersibility of the nano material in advance, so that the high-performance anti-corrosion reinforcing agent is beneficial to being applied to a concrete system. The hydroxyl compound is mainly used for improving the stability of the nano modified material in an aqueous dispersion system, and most of the selected hydroxyl compounds are polyhydroxy compounds with larger molecular weight, have certain thickening property and water locking property, can lock the dispersion of the nano material in water, and reduce the problem of uneven dispersion of aggregation, agglomeration, gel, layering and the like caused by the collision of the nano material.

The high-performance anti-corrosion reinforcing agent has the following advantages:

1. the high-performance concrete anti-corrosion reinforcing agent adopts the nano material as the main anti-corrosion reinforcing material, has a dense filling effect, can effectively optimize and improve the pore compactness of concrete, and effectively solves the problems that the dispersibility of the common nano material in the concrete is poor, only early hydration is promoted only by being used as a seed crystal, and the long-term durability of the concrete is not remarkably improved by modifying the surface of the organic carboxylic acid and the organic siloxane.

2. The physical adsorption and chemical bonding modification of the surface of the nano material can better regulate and control the activity release time of the nano material, wherein the physical adsorption of organic carboxylic acid generally has relatively short time when the surface of the nano material is exposed and the hydration product is in the state, and the time when the surface of the nano material is exposed and the surface of the nano material is subjected to new reaction after chemical bonding is longer, so that the combination of the short-term performance and the long-term performance of the nano material is realized, and the effective improvement and improvement of the corrosion resistance of the concrete in the whole life cycle are achieved.

3. The overall corrosion resistance of the concrete can be improved finally through the selection and combination of different alkyl or aryl chain lengths of the organic carboxylic acid or the organic siloxane.

4. The alkanolamine compound and the nano modified material act together to realize further regulation and improvement of the cement post hydration process, further improve the effectiveness of the nano material in the process of compacting concrete pores and realize filling and compaction.

5. The preparation process is simple and convenient to implement, and the prepared product has the characteristics of environment friendliness, high efficiency and the like, and is very suitable for corrosion protection of reinforced concrete structures in environments eroded by various complex harmful ions such as saline-alkali soil, ocean and the like.

Detailed Description

The invention is described in detail below by way of examples which are illustrative only and are not meant to limit the scope of applicability of the invention, as the skilled artisan will be able to modify the reagents, catalysts and reaction process conditions within the scope of the invention in light of the disclosure herein. All equivalent changes or modifications made in accordance with the spirit of the present invention should be construed to be included in the scope of the present invention.

Example 1

The modified nano silicon dioxide is prepared by acidizing 5g of 10nm silicon dioxide in a hydrochloric acid system with the particle size of 0.01mol/L, adding 1g of dodecyl triethoxy silane and 1g of acetic acid after the acidizing, and carrying out atomization mixing treatment at the temperature of 120 ℃.

85g of water, 10g N-methyl diethanolamine and 0.2g of cellulose ether (with the molecular weight of 200 ten thousand) are added into a reaction kettle, after uniform stirring, modified nano silicon dioxide is added into the aqueous solution, the pH value in the solution is controlled to be 5-9, rapid stirring is carried out, after the nano silicon dioxide is added, stirring is continued until the system is stable, and the prepared high-performance concrete anti-corrosion reinforcing agent is obtained.

Example 2

Acidizing 30g of silicon dioxide with the particle size of 50nm in a hydrochloric acid system with the particle size of 0.01mol/L, adding 6g of lauric acid after the acidizing, and carrying out atomization mixing treatment at the temperature of 200 ℃ to obtain the lauric acid modified nano silicon dioxide.

Adding 80 water, 5g of ethanolamine and 0.5g of Vanilla gum (with the molecular weight of 1000 ten thousand) into a reaction kettle, uniformly stirring, adding modified nano silicon dioxide into the aqueous solution, controlling the pH in the solution to be 5-9, rapidly stirring, and continuing stirring until the system is stable after the nano silicon dioxide is added, thereby obtaining the prepared high-performance concrete anti-corrosion reinforcing agent.

Example 3

Acidizing aluminum oxide with the particle size of 20g and 30nm in a nitric acid system with the particle size of 0.01mol/L, adding 0.5g of n-butyl trimethoxy silane and 2g of octanoic acid after the acidizing, and carrying out atomization mixing treatment at the temperature of 80 ℃ to obtain the modified nano silicon dioxide.

Adding 80 water, 25g of triethanolamine and 0.6g of cellulose ether (with the molecular weight of 200 ten thousand) into a reaction kettle, uniformly stirring, adding modified nano silicon dioxide into the aqueous solution, controlling the pH in the solution to be 5-9, rapidly stirring, and continuing stirring until the system is stable after the nano silicon dioxide is added, thereby obtaining the prepared high-performance concrete anti-corrosion reinforcing agent.

Example 4

Acidizing 40g of aluminum oxide with the particle size of 100nm in a hydrochloric acid system with the particle size of 0.01mol/L, adding 5g of sunflower acid after the acidizing, and carrying out atomization mixing treatment at the temperature of 180 ℃ to obtain the modified nano silicon dioxide.

50g of water, 15g of N, N-tetrahydroxyethyl ethylenediamine and 0.05g of xanthan gum (molecular weight of 500 ten thousand) are added into a reaction kettle, after uniform stirring, modified nano silicon dioxide is added into the aqueous solution, the pH in the solution is controlled to be 5-9, rapid stirring is carried out, and after the nano silicon dioxide is added, stirring is continued until the system is stable, thus obtaining the prepared high-performance concrete anti-corrosion reinforcing agent.

Example 5

50g of copper oxide with the particle size of 500nm is acidified in a hydrochloric acid system with the particle size of 0.01mol/L, 3g of octanoic acid is added after the acidification treatment, and atomization mixing treatment is carried out at the temperature of 100 ℃ to obtain the modified nano silicon dioxide.

Adding 40g of water, 20g of triisopropanolamine and 0.05g of cyclodextrin (with the molecular weight of 500 ten thousand) into a reaction kettle, uniformly stirring, adding modified nano silicon dioxide into the aqueous solution, controlling the pH in the solution to be 5-9, rapidly stirring, and continuing stirring until the system is stable after the nano silicon dioxide is added, thereby obtaining the prepared high-performance concrete anti-corrosion reinforcing agent.

Example 6

Acidizing 30g of copper oxide with the particle size of 10nm in a nitric acid system with the particle size of 0.01mol/L, adding 0.5g of oleic acid after the acidizing, and carrying out atomization mixing treatment at the temperature of 240 ℃ to obtain the modified nano silicon dioxide.

Adding 70g of water, 10g of dimethylethanolamine and 0.02g of chitosan (molecular weight of 1000 ten thousand) into a reaction kettle, uniformly stirring, adding modified nano silicon dioxide into the aqueous solution, controlling the pH in the solution to be 5-9, rapidly stirring, and continuing stirring until the system is stable after the nano silicon dioxide is added, thereby obtaining the prepared high-performance concrete anti-corrosion reinforcing agent.

Example 7

Acidizing 20g of nano silicon dioxide with the particle size of 800nm in a hydrochloric acid system with the particle size of 0.01mol/L, adding 0.6g of hexadecyl triethoxy siloxane after the acidizing, carrying out atomization mixing treatment at the temperature of 280 ℃, and carrying out surface modification treatment to obtain the modified nano silicon dioxide.

Adding 70g of water, 10g of dimethylethanolamine and 0.05g of chitosan (molecular weight of 1000 ten thousand) into a reaction kettle, uniformly stirring, adding modified nano silicon dioxide into the aqueous solution, controlling the pH in the solution to be 5-9, rapidly stirring, and continuing stirring until the system is stable after the nano silicon dioxide is added, thereby obtaining the prepared high-performance concrete anti-corrosion reinforcing agent.

Comparative example 1

This comparative example was set based on example 1, and differs from example 1 in that the nanomaterial was not subjected to modification treatment.

Silica with a particle size of 5g 10nm was acidified in a 0.01mol/L hydrochloric acid system.

85g of water, 10g N-methyl diethanolamine and 0.2g of cellulose ether (with the molecular weight of 200 ten thousand) are added into a reaction kettle, after uniform stirring, the acidized nano-silica is added into the aqueous solution, the pH value in the solution is controlled to be 5-9, rapid stirring is carried out, after the nano-silica is added, stirring is continued until the system is stable, and the prepared high-performance concrete anti-corrosion reinforcing agent is obtained.

Application examples

Concrete durability tests are carried out on the samples of the examples and the comparative examples by referring to GB/T50082 Standard of test method for the long-term performance and durability of ordinary concrete, and the influence of different samples on the sulfate corrosion resistance, carbonization resistance, freeze thawing resistance and other properties of the concrete are mainly examined, wherein the W/C=0.40 of the concrete, the cement is ordinary Portland cement (conch P.O.42.5), the sand is river sand, the stone is basalt, the grain size range is 5-15mm and 10-25mm, and the sand rate is 0.39; the mixing amount of the concrete anti-corrosion reinforcing agent is 10% of that of the cementing material, water is equally buckled in the application process, the reference group is the concrete without the high-performance concrete anti-corrosion reinforcing agent, and the experimental results are shown in the following table.

TABLE 1 influence of different comparisons and examples on the mechanical and corrosion resistance properties of concrete

The results in the table show that the high-performance concrete corrosion-resistant reinforcing agent disclosed by the invention can obviously improve the sulfate corrosion resistance of concrete, reduce the carbonization depth of concrete, strengthen the freeze-thawing cycle times of concrete, effectively improve the durability of a concrete structure, strengthen the corrosion resistance of the concrete and prolong the service life of the structure.

Claims (8)

1. The high-performance concrete anti-corrosion reinforcing agent is characterized by comprising the following components in percentage by mass:

modified nanomaterial: 4 to 50 percent,

alkyl alcohol amine: 2% -20%,

polyhydroxy compound: 0.01% -5%,

water: the balance of the total number of the components,

the sum of the mass percentages of the components is 100 percent;

the modified nano material is a nano material with the surface treated by an organic modifier; the organic modifier is organic siloxane or organic carboxylic acid or a combination of the two; the organic carboxylic acid is fatty acid or aromatic carboxylic acid with 1-20 carbon atoms; the organic siloxane is methoxy or ethoxy siloxane with 1-20 carbon atoms; the nano material is one or a combination of more of nano silicon dioxide, nano aluminum oxide and nano copper oxide;

the polyhydroxy compound is one or a combination of more of cellulose ether, polyvinyl alcohol, cyclodextrin, chitosan, xanthan gum and varen gum.

2. The high-performance concrete corrosion-resistant reinforcing agent according to claim 1, wherein the modified nano material is 4-8% by mass, the alkyl alcohol amine is 6-12% by mass, and the polyhydroxy compound is 0.1-3% by mass.

3. The high performance concrete corrosion protection enhancer of claim 1, wherein the mass ratio of the organic modifier to the nanomaterial is 1:1-300.

4. The high performance concrete corrosion protection enhancer of claim 1, wherein the nanomaterial size ranges from 5 to 1000nm.

5. The high performance concrete corrosion inhibitor according to claim 1, wherein the organosiloxane is a methoxy or ethoxy siloxane having 4 to 12 carbon atoms.

6. The high performance concrete corrosion inhibitor of claim 1, wherein the alkanolamine is one or a combination of several of ethanolamine, diethanolamine, triethanolamine, dimethylethanolamine, N-methylethanolamine, N-methyldiethanolamine, ethylene glycol monoisopropanolamine, triisopropanolamine, N-tetrahydroxyethyl ethylenediamine.

7. The high performance concrete corrosion protection enhancer of claim 1, wherein the cellulose ether has a molecular weight of 10 to 1000 tens of thousands; the molecular weight of the polyvinyl alcohol is 5 ten thousand to 1000 ten thousand; the cyclodextrin is alpha, beta or gamma cyclodextrin; the chitosan is chitosan with the molecular weight of 10 ten thousand to 1000 ten thousand.

8. The method for preparing the high-performance concrete anti-corrosion reinforcing agent according to any one of claims 1 to 7, which is characterized by comprising the following steps:

(1) Acidizing the nano material, adding an organic modifier, atomizing and mixing at 60-300 ℃, and uniformly mixing the nano material and the organic modifier to obtain the modified nano material;

(2) Adding water, alkanolamine and polyhydroxy compound into a reaction kettle, uniformly mixing, adding the modified nanomaterial in the step (1), controlling the pH value in the solution to be 5-9, and obtaining the high-performance concrete anti-corrosion reinforcing agent after the system is stable.