Medium transmission inhibitor for concrete, its manufacturing method and application

Abstract

This application discloses organosilicon nanoprecursor medium transmission inhibitors, their preparation methods and applications. [Solution] The organosilicon nano-precursor media transmission inhibitor consists of an organosilicon compound and its derivative, a catalyst, a dispersant, a stabilizer, a surfactant, and water. During the hydration process, the organosilicon nano-precursor media transmission inhibitor generates nanoparticles in situ that have water-repellent properties and can effectively fill the pores in concrete, thereby effectively solving the problem of hydrophobic materials being unable to reduce the diffusion of aggressive media when saturated with water. The in-situ generation of nanoparticles effectively solves problems such as uneven dispersion and stability deterioration that exist with added nanomaterials, and effectively improves the concrete's resistance to ion erosion.

Description

[Technical Field]

[0001] This application claims priority from a Chinese patent application entitled "Organosilicon nano-precursor medium transmission inhibitor, its manufacturing method and application," filed with the China Patent Office on June 29, 2020, the entire contents of which are incorporated herein by reference. The present application relates to functional materials, which are particularly suitable for inhibiting the transmission of corrosive media in concrete, and belong to the field of building materials. [Background technology]

[0002] Corrosion and destruction of reinforced concrete is becoming more and more common, and in serious cases can cause serious accidents. Engineers and technicians around the world are constantly interested in improving the corrosion resistance of reinforced concrete, especially with the rapid development of the economy and society, the continuous expansion of engineering application fields, and the increasing prevalence of severe corrosive environments. Practical measures to provide long-lasting corrosion resistance are effective means to reduce corrosion failure and extend the life of structures.

[0003] The key to improving the durability of concrete is to reduce the transmission of corrosive media through the concrete, and common technical means include reducing the water-binder ratio and using mineral admixtures. Reducing the water-binder ratio or reducing the amount of water used has a significant effect on the workability of ready-mix concrete. The use of mineral admixtures such as fly ash, mineral powder, and silica fume may result in low early strength of concrete, a large carbonation depth, and increased cracking due to shrinkage. As a general technical measure as described above, mainly by reducing the number of vacancies and optimizing the vacancy structure, the number of paths through which corrosive ions can be transmitted is reduced. Previous studies have shown that the most severe areas of corrosion in reinforced concrete are the alternating wet-dry zone and the splash zone. This is because in these regions there is a capillary phenomenon, similar to the "Edgewick effect," which promotes rapid transport and concentration of corrosive ions. Therefore, reducing capillary action is key in suppressing media transmission in areas where corrosion is most severe.

[0004] Generally, the technical means for reducing capillary action are divided into overcoating and doping with a medium transmission resistance suppressing material. Known coating techniques include penetration-type organic silane coating and film-forming-type coating (EP Patent Nos. 0538555 and 0340816). Silicone emulsions can be applied to the surface of concrete, forming a hydrophobic layer on the surface of the concrete, which prevents the transmission of corrosive media into the concrete. However, the uniformity of the surface application and the deterioration of performance after long-term use both reduce the resistance to media transmission.

[0005] Other preservatives for overcoating, including acrylates and epoxy resins, can completely isolate corrosive media, but the biggest challenges with these preservatives when used with concrete are poor adhesion, rapid aging, and lack of breathability. Therefore, the durability of the concrete surface to which the external protective material is actually applied is insufficient, and it is difficult to remove from the surface of the structure after it has expired.

[0006] Doping concrete with hydrophobic materials can inhibit the transmission of aggressive media, and in recent years this has been studied and has attracted the attention of scholars, engineers, and technicians. However, conventional hydrophobic doping materials themselves have a significant adverse effect on the strength development of concrete. For example, stearic acid emulsions generally reduce the strength of concrete by 15-30% (Construction and building materials 227(2019)11678), which may result in failure to ensure the mechanical performance of the construction structure.

[0007] Chinese Patent No. 1106363 describes a method for preparing a sufficiently homogeneously hydrophobic concrete by adding a hydrolyzable water emulsion containing an organosilicon compound to fresh concrete prepared from water, inorganic components and optional organic components before hardening, which can inhibit the transmission of corrosive media to a certain extent. However, when the concrete is fully saturated with water, such materials have little effect on improving the diffusion of aggressive media, and may even increase the diffusion of aggressive ions in the concrete when saturated with water, thereby failing to achieve the effect of suppressing the transmission of media.

[0008] Chinese Patent No. 1233774 and Chinese Patent Application Publication No. 102424542 disclose nano-silicon water repellents composed of components such as sodium methyl silicate or sodium silanolate, sodium methyl silanolate or high-boiling sodium silanolate, nano-scale silicon dioxide, acrylic silicone emulsion or styrene acrylate elmation or pure acrylic elmation, monoethanolamine, diethanolamine or triethanolamine, and deionized water. However, waterproofing materials such as sodium methyl silicate have a serious effect on the setting time of concrete, which limits their practical use in applications, and at the same time, they are difficult to achieve an efficient hydrophobic effect in a saturated state. Although adding nanomaterials to concrete can reduce the medium diffusion in concrete under saturated conditions to a certain extent, the nanomaterials themselves have low stability and are difficult to disperse effectively and uniformly when mixed into concrete, so their actual application effect is still not ideal. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention improves the resistance of concrete to ionic attack to overcome the shortcomings of the prior art. Transmission retardant for concreteto provide. Concrete medium transmission inhibitor generate nanoparticles in situ during the hydration process, which have water-repellent properties and can effectively fill the pores of concrete, effectively solving the problem that hydrophobic materials cannot reduce the diffusion of aggressive media in saturated water conditions.

[0010] Furthermore, by generating nanoparticles in situ in the pores of concrete, problems such as uneven dispersion and deterioration of stability that exist in additionally added nanomaterials can be effectively solved. [Means for solving the problem]

[0011] The present application Transmission retardant for concrete The composition is composed of 2 to 70 parts by weight of an organosilicon compound or its derivative, 0.01 to 10 parts by weight of a catalyst, 0.01 to 10 parts by weight of a dispersant, 0.01 to 5 parts by weight of a stabilizer, a surfactant, and 30 to 95 parts by weight of water.

[0012] The organosilicon compounds and derivatives thereof are polymers having a linear or branched structure and containing 1 to 1,000 silicon atoms, a molecular weight of 100 to 100,000, and selected from the group consisting of silicate esters, alkyl silicates, alkyl siloxanes, alkenyl siloxanes, and alkyl siloxanes or polysiloxanes containing functional heteroatoms.

[0013] The catalyst is selected from phenol and its derivatives, benzoquinone and its derivatives, , Gu The alcohol amine is one of amines, derivatives thereof, and low molecular weight alcohol amines having a molecular weight of 50 to 1000.

[0014] The dispersant is a polymer dispersant made of one or two of acrylic acid and its derivatives, maleic acid and its derivatives, and fumaric acid and its derivatives.

[0015] The stabilizer is a polysaccharide, chitosan, a cellulose ether, a polyamide, and / or a polypyrrolidone.

[0016] Some organosilicon compounds and their derivatives have low solubility in water, so it is necessary to add a surfactant to emulsify or microemulsify the compounds to improve their multiphase dispersion. The surfactant is a cationic surfactant, an anionic surfactant, or a nonionic surfactant having an HLB value of 5 to 14, Sorbitan fatty acid ester ( Span ) , Polyoxyethylene sorbitan fatty acid ester ( Tween ) , polyoxyethylene isoalcohol ether, alkyl carboxylate, alkyl sulfonate, alkyl quaternary ammonium salt, etc. Preferred surfactants are Sorbitan fatty acid ester ( Span ) , alkyl carboxylates, and alkyl quaternary ammonium salts.

[0017] Preferably, the organosilicon compounds and derivatives thereof are γ-aminopropyl having a group Siloxane, silane oligomer, and / or allyltriethoxysilane.

[0018] Preferably, the catalyst is guanidine phosphate and / or p-benzoquinone.

[0019] Preferably, the dispersant has a molecular weight of 1,000 to 40,000.

[0020] The organosilicon compound has its own performance property of low interfacial tension, which can effectively inhibit the penetration of moisture and aggressive media, thereby providing hydrophobicity and media transmission resistance. At the same time, the organosilicon functional group has a chemical composition similar to that of inorganic materials, particularly concrete materials, and can form a strong chemical bond at the interface of inorganic cementitious materials. Thus, an organic / inorganic hybrid system is formed, improving the physical and chemical performance of the inorganic material surface.

[0021] The catalyst acts on silicate hydrates, etc., produced by the hydration of organosilicon compounds and their derivatives with cement, in response to the strong alkaline environment of concrete, to produce organic / inorganic hybrid nanomaterials in situ within the pores of the concrete, consisting of elements such as oxygen, silicon, and carbon.

[0022] A distinctive feature of the present application is that the manufactured Transmission retardant for concrete The pH value of the product system is close to neutral, and the catalyst does not cause a reaction of organosilicon compounds and their derivatives in the product system, which is close to neutral. When mixed into concrete, the reaction occurs due to the strong alkalinity caused by cement hydration in the concrete environment, resulting in hydrophobicity. of The nanoparticles are generated in situ.

[0023] In this application, dispersion Agent By adding ingredients, nano particle precursor Organosilicon compounds and their derivatives as While it is possible to uniformly disperse the Agent Depending on the ingredients, during the hydration process Organosilicon and its derivatives: Transmission retardants for concrete This can promote more uniform dispersion of the nanoparticles produced by the reaction of the hydroxybenzoate with the cement hydration products.

[0024] The greatest feature of this application is that it does not simply improve the performance of concrete by using organosilicon compounds, but by combining them with different catalysts, dispersants, stabilizers, surfactants, etc., it is possible to uniformly distribute organosilicon compounds and their derivatives throughout the concrete, and as cement hydration progresses within the concrete, they participate in the hydration reaction, generating hydrophobic nanoparticles in situ, while simultaneously improving the compaction of the concrete.

[0025] At the same time, Transmission retardant for concretefurther contains a stabilizer component to improve the stability of the organosilicon compound and its derivatives in an aqueous system, while improving the stability of the nanoparticles after the action of the organosilicon compound and its derivatives with the hydration product.

[0026] The medium transmission inhibitor for concrete according to the present invention The manufacturing method includes the steps of adding an organosilicon compound and its derivative and a dispersant to a reaction vessel and raising the temperature to 10 to 200°C, adding a surfactant and stirring for 1 to 24 hours, and adding a catalyst, a stabilizer and water and continuing to stir for 1 to 24 hours.

[0027] The present application Transmission retardant for concrete In the application method of Transmission retardant for concrete In the mixing process of the cementitious material, the amount of cement used in the cementitious material is 3L / m 3 ~50L / m 3 to form a dense medium transmission resistance material after the cementitious material hardens. DETAILED DESCRIPTION OF THE INVENTION

[0028] To better illustrate the beneficial effects of the present application, the application will be considered using examples. Six example samples were prepared and compared with a good commercial product, DOW SHP 60, in concrete performance and media transmission resistance tests.

[0029] Table 1 shows the compounding ratios of specific Examples S1 to S6.

[0030] Table 1. Sample composition JPEG0007766306000001.jpg102168Table 1 Sample composition (continued) JPEG0007766306000002.jpg97169

[0031] Table 1 shows the compounding ratios of the prepared samples. Stable performance due to different composition and ratio combinations Transmission retardant for concrete is produced and incorporated into concrete. Table 2 shows the concrete mix ratio.

[0032] Table 2 Concrete mix ratio kg / m 3 JPEG0007766306000003.jpg102169

[0033] The effects of different samples on performance such as concrete workability, mechanical properties, hydrophobicity and resistance to chloride ion diffusion were compared. The water absorption rate was measured in accordance with BS 1882, and the chloride ion diffusion coefficient was measured in accordance with the electromigration chloride ion diffusion coefficient RCM method in GB 50082 "Test methods for medium- to long-term durability of ordinary concrete." The test results are shown in Table 3.

[0034] Table 3. Effect of different samples on concrete performance JPEG0007766306000004.jpg78169

[0035] From the test results, Transmission retardant for concrete It was found that the addition of this agent has little effect on the workability and mechanical properties of concrete, while at the same time effectively reducing the water absorption rate of concrete, is more hydrophobic than similar organosilicon water repellents, significantly reduces the diffusion coefficient of chloride ions even in a saturated state, and improves the resistance of concrete to ion erosion.

Claims

1. A medium transmission inhibitor for concrete, It consists of 2 to 70 parts by weight of an organosilicon compound and its derivative, 0.01 to 10 parts by weight of a catalyst, 0.01 to 10 parts by weight of a dispersant, 0.01 to 5 parts by weight of a stabilizer, a surfactant, and 30 to 95 parts by weight of water, The organosilicon compound and derivatives thereof have a number of silicon atoms of 1 to 1,000 and a molecular weight of 100 to 100,000, and are at least one selected from the group consisting of alkenylsiloxanes, siloxanes having a γ-aminopropyl group, and silane oligomers; The catalyst does not undergo a reaction in a neutral environment, but when the medium transmission inhibitor for concrete is mixed into concrete, it undergoes a reaction to produce hydrophobic nanoparticles in situ from the organosilicon compound and its derivatives; the hydrophobic nanoparticles are organic / inorganic hybrid nanomaterials consisting of oxygen, silicon, and carbon; the catalyst is one of benzoquinone and guanidine; the dispersant is a polymer dispersant consisting of one or two of acrylic acid and its derivatives, maleic acid and its derivatives, and fumaric acid and its derivatives; The medium transmission inhibitor for concrete, wherein the stabilizer is at least one selected from the group consisting of polysaccharides, chitosan, cellulose ethers, polyamides, and polypyrrolidones.

2. The surfactant has an HLB value of 5 to 14 and is at least one selected from the group consisting of cationic surfactants, anionic surfactants, and nonionic surfactants.

3. The medium transmission inhibitor for concrete according to claim 2, characterized in that the surfactant is one or a combination of several of sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene isoalcohol ether, alkyl carboxylate, alkyl sulfonate, and alkyl quaternary ammonium salt in any proportion.

4. The medium transmission inhibitor for concrete according to claim 3, characterized in that the surfactant is a mixture of one or two of sorbitan fatty acid ester, alkyl carboxylate, and alkyl quaternary ammonium salt.

5. The organosilicon compound and its derivatives are at least one selected from the group consisting of siloxanes having a γ-aminopropyl group, silane oligomers, and allyltriethoxysilanes.

6. The medium transmission inhibitor for concrete according to claim 1, wherein the dispersant has a molecular weight of 1,000 to 40,000.

7. A method for producing a medium transmission inhibitor for concrete according to any one of claims 1 to 6, adding the organosilicon compound and its derivative and the dispersant to a reaction vessel and heating the vessel to a temperature of 10°C to 200°C; adding the surfactant and stirring for 1 hour to 24 hours; A manufacturing method comprising the steps of adding the catalyst, the stabilizer and the water and continuing to stir for 1 to 24 hours to obtain the medium transmission inhibitor for concrete.

8. 7. Application of the medium transmission inhibitor for concrete according to any one of claims 1 to 6, characterized in that it is used as a concrete protection material.

9. The medium transmission inhibitor for concrete is added to the cementitious material in the mixing process of the cementitious material in an amount of 3 L / m based on the total volume of the concrete material. ３ Up to 50 L / m ３ 9. The application of claim 8, characterized in that the cementitious material is added in a mixed amount of 0.1 to 1.0 times the amount of the cementitious material, and forms a dense medium transmission resistance material after the cementitious material hardens.

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