Concrete steam-cured steel bar rust inhibitor and preparation method thereof

Abstract

The present invention discloses a concrete steam-cured steel bar rust inhibitor and a preparation method thereof, belonging to the technical field of building material rust prevention. The rust inhibitor uses azide and alkynol as raw materials to generate an intermediate product, which is then separated by vacuum negative pressure with a siloxane compound under the action of a catalyst to generate the corresponding concrete steam-cured steel bar rust inhibitor. The concrete steam-cured steel bar rust inhibitor prepared by the present invention introduces a five-membered ring and heteroatoms N and O into the benzene ring structure. The molecule contains π bonds and empty orbitals that can coordinate and bond with metal atoms. It can be used in steam-cured concrete structures. On the one hand, the steam-cured steel bar rust inhibitor can be rapidly adsorbed on the steel bar surface without dissipating at high temperatures, inhibiting steel bar corrosion and having excellent rust inhibition performance. On the other hand, the steam-cured steel bar rust inhibitor of the present invention combines with the hydration products in the concrete to have a good hydrophobic effect.

Description

Technical Field

[0001] The invention belongs to the technical field of rust prevention of building materials, and particularly relates to a concrete steam-cured steel bar rust inhibitor and a preparation method thereof. Background Art

[0002] Steel bar corrosion is one of the main threats to the durability of concrete structures, especially in harsh environmental conditions (such as marine environment, saline-alkali land, high temperature and high humidity areas, etc.), the corrosion rate of steel bars will be significantly accelerated, resulting in a decrease in the bearing capacity and safety of concrete structures. Therefore, the development of efficient and environmentally friendly steel bar corrosion prevention materials is of great significance for extending the service life of concrete structures and ensuring project safety. The mechanism of steel bar corrosion mainly involves the electrochemical corrosion process. In the strong alkaline environment of concrete, a dense passivation film will form on the surface of the steel bar, which plays a protective role. However, when harmful media (such as CO2, Cl - When the steel bar is intruded by the iron (such as iron, etc.), the passive film will be destroyed, and the steel bar will be activated, thus electrochemical corrosion will occur. During the corrosion process, the iron atoms in the anode area lose electrons and become Fe 2+ The cathode accepts electrons and generates hydroxide ions, while the oxygen and water in the cathode accept electrons and generate hydroxide ions. This process repeats over and over again, causing the steel bars to corrode gradually, which in turn affects the overall performance of the concrete structure.

[0003] In order to effectively protect steel bars from corrosion, a variety of measures need to be taken, including improving the density of concrete and using rust inhibitors. Among them, rust inhibitors, as chemical substances that act directly on the surface of steel bars, can significantly delay or prevent the corrosion process of steel bars. High-temperature steam curing technology is a method of accelerating the hardening and strength development of concrete by increasing the curing temperature. This technology can significantly shorten the curing cycle of concrete and improve production efficiency. However, under high-temperature steam curing, not only will the internal gas of the concrete expand and the free water evaporate and escape, but the high temperature will also cause the commonly used rust inhibitors to dissipate, making the steel bars more susceptible to corrosion and oxidation in the environment, resulting in insufficient rust inhibition performance and shortening the service life of the concrete. For this reason, a high-temperature steam-cured steel bar rust inhibitor is needed to overcome this problem. CN107572858B discloses a reinforced concrete rust inhibitor and its preparation method. The invention discloses a rust inhibitor prepared from 30-60 parts of a modified oyster mushroom extract, 1-4 parts of calcium gluconate, 2-10 parts of sodium dodecylbenzene sulfonate, and 30-67 parts of water. The N, S, and other heteroatoms contained in the modified oyster mushroom extract can effectively bind to Fe, resulting in a stable structure and forming a dense passivation layer. Calcium gluconate can form a complex with Fe, eliminating localized corrosion caused by uneven thickness of the passivation layer and creating a synergistic effect with the modified oyster mushroom extract to improve the rust inhibition effect. Sodium dodecylbenzene sulfonate adsorbs sulfonic acid groups on Fe, distributing the alkyl groups externally and creating a hydrophobic function, thus preventing water from participating in the corrosion reaction of the steel bars. However, the modified oyster mushroom extraction process is complex, and the product is a mixture. Its rust inhibition performance is unstable, with varying degrees of effectiveness, and it easily dissipates under high-temperature steam curing. CN 101358014A is a patent application filed by Evonik Degussa GmbH of Germany: a mixture containing an organosilicon compound and its application. The patent discloses that the mixture can significantly improve the corrosion resistance of building stones, building components or buildings and corresponding steel bars or metal bars after treatment, and the substrate using the mixture has good hydrophobicity. However, the ability to inhibit steel bar corrosion is limited, and accelerated corrosion can occur under steam curing conditions. The preparation process is also complex. Summary of the Invention

[0004] Technical problem to be solved: In order to solve the problem that existing rust inhibitors have poor rust inhibition effect and are easily dissipated under high-temperature steam-curing conditions, the present invention provides a concrete steam-cured steel bar rust inhibitor and a preparation method thereof. The rust inhibitor does not dissipate at high temperatures, can be quickly adsorbed on the surface of steel bars, inhibiting steel bar corrosion, and can also react with hydration products in concrete, having the ability to inhibit water absorption.

[0005] Technical solution: A concrete steam-cured steel bar rust inhibitor, comprising at least one of components (I), (II), and (III). The structural formulas of components (I), (II), and (III) are as follows:

[0006] ,

[0007] ,

[0008] ,

[0009] wherein s is an integer of 1 to 30; t is an integer of 1 to 15; R1 is H or an amino group; R2 and R3 are alkyl groups with 1 to 6 carbon atoms; and R4 is H or an alkyl group with 1 to 10 carbon atoms.

[0010] Preferably, the amount of the rust inhibitor added to the concrete is 0.1% to 10% of the mass of the cementitious material used in the concrete.

[0011] The preparation method of the above-mentioned concrete steam-cured steel bar rust inhibitor comprises the following steps:

[0012] Step 1. Under nitrogen atmosphere, an organic solvent, catalyst A, and azide and alkynol are sequentially added to a reactor in a molar ratio of 1:(1.0-1.2). The reaction is stirred at a temperature of 40-70°C for 6-48 hours. After the reaction is completed, extraction is performed three times. The organic phases are combined and dried, filtered, and the organic solvent is removed by rotary evaporation to obtain an intermediate product.

[0013] Step 2. Place the intermediate product into a reactor, add the siloxane compound and catalyst B, stir and react for 5 to 48 hours in a nitrogen environment, at a temperature of 100 to 200° C. and under vacuum negative pressure, and divide the solution once every 2 hours. After the reaction is completed, the concrete steam-cured steel bar rust inhibitor is obtained.

[0014] Preferably, in step 1, the organic solvent is dimethyl sulfoxide or dimethylformamide.

[0015] Preferably, in step 1, the catalyst A is CuI, and its dosage is 1% to 2% of the mass of the azide.

[0016] Preferably, in step 1, the structure of the azide is as follows:

[0017] , wherein R1 is H or amino.

[0018] Preferably, in step 1, the structure of the alkynol is as follows:

[0019] , where m is an integer from 1 to 15.

[0020] Preferably, in step 1, the structure of the intermediate product is as follows:

[0021] , wherein R1 is H or amino; t is an integer from 1 to 15.

[0022] Preferably, in step 2, the structure of the siloxane compound is as follows:

[0023] , wherein s is an integer of 1 to 30; R1 is H or amino; R2 and R3 are alkyl groups with 1 to 6 carbon atoms; and R5 is an alkyl group with 1 to 6 carbon atoms.

[0024] Preferably, in step 2, the molar ratio of the intermediate product to the siloxane compound is 1:1, 2:1 or 3:1, corresponding to the generation of components (I), (II) and (III), respectively.

[0025] Preferably, in step 2, catalyst B is lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium ethoxide or sodium methoxide, and the molar ratio of catalyst B to siloxane compound is (0.01-0.1):1.

[0026] Preferably, in step 2, the vacuum negative pressure is -0.05~-0.1MPa.

[0027] Beneficial effects: The steam-cured steel bar rust inhibitor of the present invention introduces a five-membered ring and heteroatoms N and O into the benzene ring structure. The molecule contains π bonds and empty orbitals that can coordinate and bond with metal atoms. It has strong adsorption properties and is adsorbed on the metal surface to form a dense protective film, effectively preventing the intrusion of corrosive media such as chloride ions and oxygen, thereby delaying or preventing the occurrence of steel bar corrosion, and has a good rust-inhibiting effect.

[0028] The concrete steam-cured steel bar rust inhibitor of the present invention can maintain its chemical stability and physical properties during the high-temperature steam-curing process, does not decompose or volatilize, ensures the rust-proof effect, and has good long-term effectiveness.

[0029] The steam-cured steel bar rust inhibitor of the present invention is easy to construct, has good fluidity and operability, is easy to disperse evenly during the concrete mixing process, and does not affect other properties of the concrete. DETAILED DESCRIPTION

[0030] The present invention will be further described below with reference to specific embodiments.

[0031] Example 1

[0032] (1) 500 g of dimethylformamide (DMF), 120 g of azidobenzene, and 2.0 g of CuI were added to the reactor and stirred uniformly. Then, 61.6 g of propargyl alcohol was added, and the temperature was raised to 50 ° C under a nitrogen environment and stirred for 24 hours. After the reaction, the obtained mixture was extracted three times with CH2Cl2, and the organic phases were combined and dried with anhydrous Na2SO4. Then, the solvent was removed by filtration and rotary evaporation to obtain the intermediate product.

[0033] (2) 1 mol of the intermediate product obtained in step (1) is placed in a reactor, and 1 mol of a siloxane compound is added, wherein R1 is amino-NH2, R2 is methyl, R3 is ethyl, and R5 is butyl. 0.01 mol of lithium hydroxide is added, and the mixture is stirred and reacted for 5 h under a nitrogen environment. The reaction temperature is 100°C, the vacuum negative pressure is -0.05 MPa, and the solution is divided once every 2 h. After the reaction is completed, a concrete steam-cured steel bar rust inhibitor with the structural formula (I) can be obtained. This concrete steam-cured steel bar rust inhibitor is recorded as I.

[0034] (3) 2 mol of the intermediate product obtained in step (1) is placed in a reactor, and 1 mol of a siloxane compound is added, wherein R1 is H, R2 is hexyl, R3 is ethyl, and R5 is butyl. 0.1 mol of sodium hydroxide is added, and the reaction is stirred for 10 h under a nitrogen environment. The reaction temperature is 150°C, the vacuum negative pressure is -0.07 MPa, and the solution is divided once every 2 h. After the reaction is completed, a concrete steam-cured steel bar rust inhibitor with the structural formula (II) can be obtained. This concrete steam-cured steel bar rust inhibitor is recorded as II.

[0035] (4) 3 mol of the intermediate product obtained in step (1) is placed in a reactor, and 1 mol of a siloxane compound is added, wherein R1 is H, R2 is methyl, R3 is ethyl, and R5 is propyl. 0.1 mol of sodium ethoxide is added, and the mixture is stirred and reacted for 48 h under a nitrogen environment. The reaction temperature is 200 ° C. and the vacuum negative pressure is -0.1 MPa. The solution is divided once every 2 h. After the reaction is completed, a concrete steam-cured steel bar rust inhibitor with the structural formula (III) can be obtained. This concrete steam-cured steel bar rust inhibitor is recorded as III.

[0036] The prepared rust inhibitors I, II, and III were evenly mixed in a mass ratio of 1:1:1, and this was used as a rust inhibitor for steam-cured steel bars in concrete, and was recorded as M1.

[0037] Example 2

[0038] (1) 500 g of dimethyl sulfoxide (DMSO), 120 g of phenylazide, and 2.4 g of CuI were added to the reactor and stirred uniformly. Then, 65 g of propargyl alcohol was added. The temperature was raised to 70 ° C under a nitrogen atmosphere and stirred for 12 hours. After the reaction was completed, the obtained mixture was extracted three times with CH2Cl2, and the organic phases were combined and dried with anhydrous Na2SO4. Then, the solvent was removed by filtration and rotary evaporation to obtain the intermediate product.

[0039] (2) 1 mol of the intermediate product obtained in step (1) is placed in a reactor, and 1 mol of a siloxane compound is added, wherein R1 is H, R2 is ethyl, R3 is ethyl, and R5 is hexyl, and 0.01 mol of sodium methoxide is added. The mixture is stirred and reacted for 24 hours under a nitrogen environment. The reaction temperature is 150°C and the vacuum negative pressure is -0.1 MPa. The solution is divided once every 2 hours. After the reaction is completed, a concrete steam-cured steel bar rust inhibitor with the structural formula (I) is obtained, which is used as a concrete steam-cured steel bar rust inhibitor and is recorded as M2.

[0040] Example 3

[0041] (1) 500 g DMSO, 120 g phenylazide, and 2.4 g CuI were added to the reactor respectively and stirred evenly. Then, 67 g propargyl alcohol was added, and the temperature was raised to 70 ° C under a nitrogen environment and stirred for 12 hours. After the reaction was completed, the obtained mixture was extracted three times with CH2Cl2, and the organic phases were combined and dried with anhydrous Na2SO4, then filtered and rotary evaporated to remove the solvent to obtain the intermediate product;

[0042] (2) 2 mol of the intermediate product obtained in step (1) is placed in a reactor, and 1 mol of a siloxane compound is added, wherein R1 is amino-NH2, R2 is butyl, R3 is butyl, and R5 is butyl. 0.05 mol of lithium hydroxide is added, and the reaction is stirred for 48 hours under a nitrogen environment. The reaction temperature is 120°C, the vacuum negative pressure is -0.1 MPa, and the solution is divided once every 2 hours. After the reaction is completed, a concrete steam-cured steel bar rust inhibitor with structural formula (II) can be obtained. This is used as a concrete steam-cured steel bar rust inhibitor and is recorded as M3.

[0043] Example 4

[0044] (1) 400 g of DMF, 161 g of 4-propylbenzeneazide, and 2.5 g of CuI were added to the reactor and stirred uniformly. Then, 140 g of 7-octyn-1-ol was added. The temperature was raised to 65 ° C under a nitrogen environment and stirred for 24 hours. After the reaction was completed, the obtained mixture was extracted three times with CH2Cl2, and the organic phases were combined and dried with anhydrous Na2SO4. Then, the solvent was removed by filtration and rotary evaporation to obtain the intermediate product.

[0045] (2) 3 mol of the intermediate product obtained in step (1) is placed in a reactor, and 1 mol of a siloxane compound is added, wherein R1 is amino-NH2, R2 is ethyl, R3 is ethyl, and R5 is ethyl, and 0.1 mol of sodium methoxide is added. The mixture is stirred and reacted for 36 hours under a nitrogen environment. The reaction temperature is 180°C and the vacuum negative pressure is -0.1 MPa. The solution is divided once every 2 hours. After the reaction is completed, a concrete steam-cured steel bar rust inhibitor with structural formula (III) is obtained, which is used as a concrete steam-cured steel bar rust inhibitor and is recorded as M4.

[0046] Example 5

[0047] 300 g of DMF, 161 g of 4-propylbenzeneazide, and 2 g of CuI were added to the reactor respectively and stirred evenly. Then, 140 g of 7-octyn-1-ol was added, and the temperature was raised to 55 ° C. under a nitrogen environment and stirred for 36 hours. After the reaction, the obtained mixture was extracted three times with CH2Cl2, and the organic phases were combined and dried over anhydrous Na2SO4, then filtered and rotary evaporated to remove the solvent to obtain an intermediate product;

[0048] (2) 1 mol of the intermediate product obtained in step (1) is placed in a reactor, and 1 mol of a siloxane compound is added, wherein R1 is H, R2 is methyl, R3 is methyl, and R5 is methyl, and 0.01 mol of sodium ethoxide is added. The reaction is stirred for 24 hours under a nitrogen environment. The reaction temperature is 180°C and the vacuum negative pressure is -0.05 MPa. The solution is divided once every 2 hours. After the reaction is completed, a concrete steam-cured steel bar rust inhibitor with the structural formula (I) can be obtained. This concrete steam-cured steel bar rust inhibitor is recorded as I.

[0049] (3) 2 mol of the intermediate product obtained in step (1) is placed in a reactor, and 1 mol of a siloxane compound is added, wherein R1 is amino-NH2, R2 is propyl, R3 is ethyl, and R5 is butyl. 0.1 mol of potassium hydroxide is added, and the reaction is stirred for 20 h under a nitrogen environment. The reaction temperature is 160°C, the vacuum negative pressure is -0.1 MPa, and the solution is divided once every 2 h. After the reaction is completed, a concrete steam-cured steel bar rust inhibitor with the structural formula (II) can be obtained. This concrete steam-cured steel bar rust inhibitor is recorded as II.

[0050] The prepared rust inhibitors I and II were mixed evenly in a mass ratio of 1:1, and this was used as a rust inhibitor for steam-cured steel bars in concrete, and was recorded as M5.

[0051] Example 6

[0052] (1) 400 g DMSO, 161 g 4-propylbenzeneazide, and 2.5 g CuI were added to the reactor respectively and stirred evenly. Then, 112 g 6-heptynol was added. The temperature was raised to 65 ° C under a nitrogen environment and stirred for 24 hours. After the reaction was completed, the obtained mixture was extracted three times with CH2Cl2, and the organic phases were combined and dried with anhydrous Na2SO4. Then, the solvent was removed by filtration and rotary evaporation to obtain the intermediate product.

[0053] (2) 1 mol of the intermediate product obtained in step (1) is placed in a reactor, and 1 mol of a siloxane compound is added, wherein R1 is H, R2 is methyl, R3 is ethyl, and R5 is propyl. 0.05 mol of sodium ethoxide is added, and the reaction is stirred for 30 hours under a nitrogen environment. The reaction temperature is 150°C, the vacuum negative pressure is -0.05 MPa, and the solution is divided once every 2 hours. After the reaction is completed, a concrete steam-cured steel bar rust inhibitor with the structural formula (I) can be obtained. This concrete steam-cured steel bar rust inhibitor is recorded as I.

[0054] (3) 3 mol of the intermediate product obtained in step (1) is placed in a reactor, and 1 mol of a siloxane compound is added, wherein R1 is amino-NH2, R2 is methyl, R3 is ethyl, and R5 is propyl. 0.1 mol of lithium hydroxide is added, and the reaction is stirred for 24 hours under a nitrogen environment. The reaction temperature is 130°C, the vacuum negative pressure is -0.1 MPa, and the solution is divided once every 2 hours. After the reaction is completed, a concrete steam-cured steel bar rust inhibitor with the structural formula (III) can be obtained. This concrete steam-cured steel bar rust inhibitor is recorded as III.

[0055] The prepared rust inhibitor I and III were evenly mixed at a mass ratio of 2:1, and this was used as a rust inhibitor for steam-cured steel bars in concrete, and was recorded as M6.

[0056] Example 7

[0057] (1) 500 g DMSO, 161 g 4-propylbenzeneazide, and 3 g CuI were added to the reactor respectively and stirred evenly. Then, 182 g dodecyl-11-yn-1-ol was added. The temperature was raised to 70 ° C under a nitrogen environment and stirred for 48 hours. After the reaction was completed, the obtained mixture was extracted three times with CH2Cl2, and the organic phases were combined and dried with anhydrous Na2SO4. Then, the solvent was removed by filtration and rotary evaporation to obtain the intermediate product.

[0058] (2) 2 mol of the intermediate product obtained in step (1) is placed in a reactor, and 1 mol of a siloxane compound is added, wherein R1 is amino-NH2, R2 is methyl, R3 is ethyl, and R5 is butyl. 0.1 mol of sodium methoxide is added, and the reaction is stirred for 48 hours under a nitrogen environment. The reaction temperature is 190°C, the vacuum negative pressure is -0.05 MPa, and the solution is divided once every 2 hours. After the reaction is completed, a concrete steam-cured steel bar rust inhibitor with the structural formula (II) can be obtained. This concrete steam-cured steel bar rust inhibitor is recorded as II.

[0059] (3) 3 mol of the intermediate product obtained in step (1) is placed in a reactor, and 1 mol of a siloxane compound is added, wherein R1 is H, R2 is methyl, R3 is ethyl, and R5 is propyl. 0.1 mol of lithium hydroxide is added, and the mixture is stirred and reacted for 36 hours under a nitrogen environment. The reaction temperature is 200°C, the vacuum negative pressure is -0.1 MPa, and the solution is divided once every 2 hours. After the reaction is completed, a concrete steam-cured steel bar rust inhibitor with the structural formula (III) is obtained, and this concrete steam-cured steel bar rust inhibitor is recorded as III.

[0060] The prepared rust inhibitor I and III were evenly mixed at a mass ratio of 1:2, and this was used as a rust inhibitor for steam-cured steel bars in concrete, and was recorded as M7.

[0061] Example 8

[0062] (1) 500 g DMSO, 161 g 4-propylbenzeneazide, and 3 g CuI were added to the reactor respectively and stirred evenly. Then, 112 g 6-heptynol was added. The temperature was raised to 55 ° C under a nitrogen environment and stirred for 24 hours. After the reaction was completed, the obtained mixture was extracted three times with CH2Cl2, and the organic phases were combined and dried with anhydrous Na2SO4. Then, the solvent was removed by filtration and rotary evaporation to obtain the intermediate product.

[0063] (2) 1 mol of the intermediate product obtained in step (1) is placed in a reactor, and 1 mol of a siloxane compound is added, wherein R1 is H, R2 is hexyl, R3 is hexyl, and R5 is hexyl, and 0.01 mol of sodium hydroxide is added. The mixture is stirred and reacted for 24 hours under a nitrogen environment. The reaction temperature is 160°C, the vacuum negative pressure is -0.1 MPa, and the solution is divided once every 2 hours. After the reaction is completed, a concrete steam-cured steel bar rust inhibitor with the structural formula (I) is obtained, which is used as a concrete steam-cured steel bar rust inhibitor and is recorded as M8.

[0064] Comparative Example 1

[0065] The commercially available amine rust inhibitor N,N-dimethylethanolamine was used as a comparative example and recorded as R1.

[0066] Comparative Example 2

[0067] Commercially available dodecyltriethoxysilane was used as a comparative example and recorded as R2.

[0068] Performance Testing

[0069] 1. Mass loss rate

[0070] The mass loss rate of the steam-cured steel bar rust inhibitor in the above embodiment was evaluated with reference to GB / T 50082 "Standard for Test Methods for Long-term Performance and Durability of Ordinary Concrete". The concrete had a W / C ratio of 0.35, the cement was Conch PO.42.5 Portland cement, the sand was river sand, the gravel was basalt, the particle size range was 5-15 mm and 10-25 mm, the sand ratio was 40%, and the benchmark was that no steam-cured steel bar rust inhibitor was added to the concrete. The steam-cured steel bar rust inhibitor for M1-M6 was 6% of the mass fraction of the cementitious material. After curing for 1 day, the test blocks were baked in an oven at 60°C for 1 day, 3 days, and 7 days. The experimental results are shown in Table 1.

[0071] Table 1 Mass loss rate of each embodiment and comparative example

[0072]

[0073] As can be seen from Table 1, the concrete steam-cured steel bar rust inhibitors M1-M8 of the present invention have low dissipation at 60°C and also have a very significant inhibitory effect on water loss. However, the mass loss rate of comparative example R1 is higher than that of the blank, indicating that in addition to water loss, the substance itself also evaporates from the interior of the concrete. The mass loss rate of comparative example R2 is relatively smaller than that of R1, but still far less than that of the concrete steam-cured steel bar rust inhibitor of the present invention.

[0074] 2. Rust resistance

[0075] The steam-cured steel bar rust inhibitor prepared by the above method was tested for steel bar corrosion area percentage ratio in a saltwater dry-wet cycle environment according to JT / T537-2018 "Reinforced Concrete Rust Inhibitors." The steel bar specimens used were reinforced with a base solution of 3g Ca(OH)2, 17.5g NaCl, and 479.5g water. The inhibitor solution was prepared by adding 6% by mass of the steam-cured steel bar rust inhibitor to the base solution. The test was conducted at a temperature of 20°C and a humidity of 77%. The steel bar corrosion area percentage ratio was calculated according to JT / T537-2018. A as well as R ,in, R The percentage ratio of the rust area of the test piece with steam-cured steel bar rust inhibitor and the reference test piece after 50 dry-wet cycles, and the rust inhibition efficiency IE =1- R The experimental calculation results are shown in Table 2.

[0076] Table 2 Rust inhibition performance of various embodiments and comparative examples

[0077]

[0078] As can be seen from Table 2, the concrete steam-cured steel bar rust inhibitors M1 to M8 of the present invention have very significant rust inhibition effects, with rust inhibition efficiencies exceeding 90%. Furthermore, it can be seen that N,N-dimethylethanolamine alone also has some rust inhibition effect, but the rust inhibition effect is inferior compared to the examples of the present invention. Furthermore, the rust inhibition effect of comparative example R2 is also inferior.

[0079] 3. Concrete hydrophobicity

[0080] The hydrophobic performance of the steam-cured steel bar rust inhibitor in the above embodiment was evaluated with reference to GB / T 50082 "Standard for Test Methods for Long-term Performance and Durability of Ordinary Concrete". The concrete contained a W / C ratio of 0.35, the cement was Conch PO.42.5 Portland cement, the sand was river sand, the gravel was basalt, the particle size range was 5-15 mm and 10-25 mm, the sand ratio was 40%, the benchmark was that no steam-cured steel bar rust inhibitor was added, and the steam-cured steel bar rust inhibitor for M1-M6 was 6% of the mass fraction of the cementitious material. The test concrete was cured to a standard temperature for 4 days, then baked in an oven at 110°C for 3 days, and finally removed and immersed in an aqueous solution for 30 minutes. The water absorption rate was the mass of the test block after immersion minus the mass of the test block before immersion divided by the mass of the test block before immersion. The experimental results are shown in Table 3.

[0081] Table 3 Concrete water absorption

[0082]

[0083] As shown in Table 3, after the steam-cured steel bar rust inhibitors M1-M8 of the present invention were incorporated into concrete, the water absorption rate after 30 minutes was significantly lower than that of the baseline group and also lower than that of the control group. This indicates that the addition of the steam-cured steel bar rust inhibitors of the present invention to concrete inhibits water absorption and reduces water absorption. Furthermore, Table 3 also reveals that the water absorption rate of the concrete in Comparative Example R1 is higher than that of the blank, indicating that it lacks hydrophobic properties. However, the water absorption rate of Comparative Example R2 is lower, indicating that dodecyltriethoxysilane has hydrophobic properties, but is less hydrophobic than the steam-cured steel bar rust inhibitors of the present invention.

[0084] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A concrete steam-cured steel bar rust inhibitor, characterized in that: It includes at least one of components (I), (II), and (III), and the structural formulas of components (I), (II), and (III) are as follows: ， ， ， wherein s is an integer of 1 to 30; t is an integer of 1 to 15; R1 is H or an amino group; R2 and R3 are alkyl groups with 1 to 6 carbon atoms; and R4 is H or an alkyl group with 1 to 10 carbon atoms.

2. A concrete steam-cured steel bar rust inhibitor according to claim 1, characterized in that: The amount of the rust inhibitor added to the concrete is 0.1% to 10% of the mass of the cementitious material used in the concrete.

3. The preparation method of the concrete steam-cured steel bar rust inhibitor according to claim 1, characterized in that: The steps are as follows: Step 1. Under nitrogen atmosphere, an organic solvent, catalyst A, and azide and alkynol are sequentially added to a reactor in a molar ratio of 1:(1.0-1.2). The reaction is stirred at a temperature of 40-70°C for 6-48 hours. After the reaction is completed, extraction is performed three times. The organic phases are combined and dried, filtered, and the organic solvent is removed by rotary evaporation to obtain an intermediate product. Step 2. Place the intermediate product into a reactor, add the siloxane compound and catalyst B, stir and react for 5 to 48 hours in a nitrogen environment, at a temperature of 100 to 200° C. and under vacuum negative pressure, and divide the solution once every 2 hours. After the reaction is completed, the concrete steam-cured steel bar rust inhibitor is obtained.

4. The preparation method of the concrete steam-cured steel bar rust inhibitor according to claim 3, characterized in that: In the step 1, the organic solvent is dimethyl sulfoxide or dimethylformamide; the catalyst A is CuI, and its dosage is 1% to 2% of the mass of the azide.

5. The preparation method of the concrete steam-cured steel bar rust inhibitor according to claim 3, characterized in that: In step 1, the structure of the azide is as follows: , wherein R1 is H or amino.

6. The preparation method of the concrete steam-cured steel bar rust inhibitor according to claim 3, characterized in that: In the step 1, the structure of the alkynol is as follows: , where m is an integer from 1 to 15.

7. The preparation method of the concrete steam-cured steel bar rust inhibitor according to claim 3, characterized in that: In the step 1, the structure of the intermediate product is as follows: , wherein R1 is H or amino; t is an integer from 1 to 15.

8. The method for preparing the concrete steam-cured steel bar rust inhibitor according to claim 3, characterized in that: In step 2, the structure of the siloxane compound is as follows: , wherein s is an integer of 1 to 30; R1 is H or amino; R2 and R3 are alkyl groups with 1 to 6 carbon atoms; and R5 is an alkyl group with 1 to 6 carbon atoms.

9. The method for preparing the concrete steam-cured steel bar rust inhibitor according to claim 3, characterized in that: In step 2, the molar ratio of the intermediate product to the siloxane compound is 1:1, 2:1 or 3:1, corresponding to the generation of components (I), (II) and (III), respectively.

10. The method for preparing the concrete steam-cured steel bar rust inhibitor according to claim 3, characterized in that: In step 2, catalyst B is lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium ethoxide or sodium methoxide, and the molar ratio of catalyst B to siloxane compound is (0.01-0.1):1; the vacuum negative pressure is -0.05-0.1 MPa.

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