Highly permeable concrete surface enhancer and method of making same
By using modified organosilicon emulsion and silicate components to form a cross-linked network structure, the reinforcing agent forms a hydrophobic layer on the concrete surface, solving the problems of insufficient permeability and durability, and improving the surface strength and impermeability of the concrete.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- WUHAN METALLURGY ARCHITECTURE RES YUAN CO LTD
- Filing Date
- 2024-08-28
- Publication Date
- 2026-06-26
AI Technical Summary
Existing concrete surface enhancers have poor penetration performance, provide little improvement in surface strength, and are insufficient in durability and impermeability.
The mixture is made of modified silicone emulsion, silicate, lithium salt, shell powder and other components to form a cross-linked network structure. The reinforcing agent forms a hydrophobic layer on the concrete surface to improve permeability and strength, and calcium gel enhances the compactness and prevents harmful substances from penetrating.
It improves the permeability, resilience, wear resistance, air tightness and carbonation resistance of concrete surfaces, reduces the penetration rate of harmful substances, and enhances the overall durability of concrete.
Smart Images
Figure BDA0005014207920000051
Abstract
Description
Technical Field
[0001] This invention belongs to the field of composite material technology, specifically relating to a high-permeability concrete surface reinforcing agent and its preparation method. Background Technology
[0002] Concrete is currently the most widely used building material in my country, so ensuring concrete quality is paramount to improving its durability. Various factors, such as uneven or discontinuous mixing during the mixing process, excessive impurities in the admixtures, excessively humid or dry cement storage environments, and unsuitable concrete mix proportions, can significantly affect concrete quality. These factors can cause the concrete surface to become dusty and sandy, resulting in lower surface strength and the appearance of microcracks. These microcracks allow harmful substances such as acids, alkalis, and salts to seep into the concrete structure, causing chemical corrosion and severely impacting the strength and durability of the concrete structure.
[0003] Concrete surface enhancer is a polymeric liquid material that is applied evenly to the concrete surface. It can quickly penetrate into the concrete and react with byproducts of cement hydration, such as calcium hydroxide, to generate a large amount of calcium carbonate. This effectively blocks the capillary micropores inside the concrete, thereby increasing the surface properties of the concrete, such as density, compressive strength, hardness, wear resistance, air tightness, impermeability, and carbonation resistance.
[0004] CN disclosed a concrete surface enhancer and its application method. The surface enhancer is prepared by mixing four components to form an organosilicon oligomer emulsion. This solves the problem that current concrete surface enhancers have low rebound values. However, the surface enhancement layer has high water absorption and poor durability, so the durability of concrete surface enhancers urgently needs further improvement.
[0005] CN202011436593.8 discloses a concrete surface enhancer and its preparation method, which consists of internal microspheres, an intermediate oil phase for coating and dispersing the internal microspheres, and an external aqueous phase for coating the intermediate oil phase. It solves the problem of poor surface strength and durability of concrete. However, the overall preparation method is relatively complex and the raw material cost is high.
[0006] CN202010513382.3 discloses a concrete surface enhancer and its preparation and application method, which uses 5% to 30% organosilicon resin, 3% to 20% talc powder, 2% to 10% sulfate, and the balance is water. It solves the problem of poor impermeability of current concrete surface enhancers, but has a low improvement in the rebound strength of concrete surface. Summary of the Invention
[0007] To address the problem that current concrete surface enhancers have poor penetration performance and provide limited improvement in surface strength, the concrete surface enhancer prepared in this invention has excellent penetration performance and sealing effect. At the same time, it can effectively improve the surface resilience of concrete, enhance the wear resistance, air tightness, impermeability and carbonation resistance of concrete.
[0008] To achieve the above objectives, the following technical solution is adopted:
[0009] The high-penetration concrete surface enhancer has the following composition by weight parts:
[0010] 30-40 parts modified silicone emulsion;
[0011] 0.5-1 part silicate;
[0012] 2-3 parts lithium salt;
[0013] 3-5 parts shell powder;
[0014] 1-2 silica sol;
[0015] 1-2 parts penetrant;
[0016] 1-2 parts film-forming aid;
[0017] 2-3 parts water-repellent agent;
[0018] 30-50 parts deionized water.
[0019] According to the above scheme, the silicate is one or any mixture of mica powder, talc powder, kaolin, and water glass.
[0020] According to the above scheme, the lithium salt is one or any mixture of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, and lithium perchlorate.
[0021] According to the above scheme, the particle size of the shell powder is between 1250 mesh and 2000 mesh.
[0022] According to the above scheme, the SiO2 content in the silica sol is 10%–20% by mass, and the particle size is 5nm–20nm. The addition of silica sol can effectively improve the weather resistance, acid resistance, and wear resistance of concrete.
[0023] According to the above scheme, the penetrant is one or more of sodium carboxymethyl cellulose or fluorocarbon surfactant.
[0024] According to the above scheme, the film-forming aid is one or a mixture of propylene glycol butyl ether and propylene glycol methyl ether acetate.
[0025] According to the above scheme, the hydrophobic agent is a mixture of allyltrimethylsilane, polypropylene glycol diglycidyl ether, and ethyl trimethylsilyl ether in a mass ratio of 3:2:5.
[0026] According to the above scheme, the preparation method of the modified organosilicon emulsion includes the following steps:
[0027] (1) Mix organosiloxane monomer, hydrophilic emulsifier, and lipophilic emulsifier and heat to 70-80℃. Stir at 600-900r / min for 3-5min. Continue to add deionized water and polyvinyl alcohol in sequence and stir to disperse evenly to obtain organosilicone pre-emulsion. The mass ratio of organosiloxane monomer, hydrophilic emulsifier, lipophilic emulsifier, deionized water, and polyvinyl alcohol is 40:(1-2):1:(30-40):(5-8).
[0028] (2) The organic amine solution, isopropoxide titanium solution and the organosilicon pre-emulsion are mixed in a reactor, heated to 40-50℃ at 10-15 MPa, and after adding the chromium-based catalyst, the mixture is mechanically stirred at 200-500 r / min for 2 h. The modified organosilicon emulsion is obtained by filtration. The amount of organic amine, isopropoxide titanium, the organosilicon pre-emulsion and chromium-based catalyst is in the mass ratio of (3-4):7:(20-25):1.
[0029] The preparation method of the above-mentioned high-permeability concrete surface enhancer includes the following steps:
[0030] The film-forming aid, penetrant, hydrophobic agent and silica sol were mixed and dispersed evenly in a portion of deionized water;
[0031] Add silicate, lithium salt and shell powder in sequence and stir until well mixed;
[0032] Finally, the modified silicone emulsion and the remaining deionized water are added and mixed evenly to obtain the high-penetration concrete surface enhancer.
[0033] This invention modifies the silicone resin emulsion, enhancing not only the permeability of the reinforcing agent but also improving its hydrophobicity through the addition of organic fluorine, thus significantly reducing the corrosion of the concrete surface by rainwater. By adding silicates and lithium salts, the reinforcing agent, after penetrating the concrete, reacts with free calcium ions within the concrete to form calcium gel. These gels enhance the density of the concrete surface, thereby increasing its surface strength. Simultaneously, the modified silicone resin and precipitated substances are thoroughly mixed to form a cross-linked network structure, which, while improving the concrete surface strength, also prevents the penetration of acidic gases and acidic soluble salts from the air.
[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0035] The concrete surface enhancer prepared in this invention exhibits excellent permeability. By modifying the organosilicon emulsion and using titanium isopropoxide solution as the titanium source, titanium is uniformly grafted onto the organosilicon chains, solving the problem of easy agglomeration of nano-titanium dioxide. Furthermore, using titanium isopropoxide as the titanium source reduces costs compared to directly using nano-titanium dioxide. Simultaneously, the Ti(OR3)3 formed in the titanium-modified organosilicon emulsion first undergoes a hydrolysis reaction with water to remove the alcohol, forming a three-dimensional cross-linked organosilicon resin. Its hydroxyl groups have a strong affinity for the concrete surface, thus firmly connecting it to the substrate. This allows the non-polar organic groups to arrange themselves outwards in an orderly manner, forming a hydrophobic layer, thereby altering the surface properties of these silicate materials, making them both water-stable and hydrophobic. Furthermore, due to the relatively small molecular weight, low surface energy, simple structure, and strong permeability of the short chains formed by titanium hydroxyl groups, they can quickly spread on the surface and penetrate the concrete surface when in contact with it. They can form a uniform, dense, and obvious three-dimensional hydrophobic network on the inner wall of the capillary pores within the base layer (7-10 mm), thus forming a permanent protective layer on the material surface and reducing the penetration rate of harmful ions.
[0036] This invention adds silicates and lithium salts, allowing the reinforcing agent to penetrate into the concrete. The silicates and lithium salts in the reinforcing agent react with free calcium ions inside the concrete to form calcium gel. These gels enhance the density of the concrete surface, thereby improving the surface strength of the concrete. At the same time, the modified organosilicon resin, mica powder, and refined shell powder are thoroughly mixed to form a cross-linked network structure. In addition, the addition of an organic water-repellent agent can effectively improve the hydrophobicity of the concrete surface. Ultimately, this reinforcing agent improves the surface strength of the concrete while preventing the penetration of acidic gases, acidic soluble salts, and other substances in the air. Detailed Implementation
[0037] The following embodiments further illustrate the technical solution of the present invention, but are not intended to limit the scope of protection of the present invention.
[0038] A specific embodiment provides a method for preparing the modified organosilicon emulsion:
[0039] Add 3g of hydrophilic emulsifier and 2g of lipophilic emulsifier to 40ml of organosiloxane monomer, then heat to 70-80℃ and stir at 600-900r / min for 3-5min; then add 100ml of deionized water and continue stirring for 5min, then gradually add 2ml of polyvinyl alcohol to obtain organosilicone pre-emulsion a; wherein the hydrophilic emulsifier is one or both of Span-85 or BASF TO-3; the lipophilic emulsifier is one or more of XP-80, AEO-5 and NP-10;
[0040] 15-18 ml of organic amine solution and 22 ml of titanium isopropoxide solution were added to a reaction vessel, followed by the addition of organosilicon pre-emulsion a. The mixture was then pressurized to 10-15 MPa under vacuum and heated to 40-50°C. 3 g of chromium-based catalyst was added, and the mixture was mechanically stirred at 200-500 r / min for 2 h. After filtration, the modified organosilicon emulsion was obtained. The organic amine solution was one or more of hexamethylenetetramine, m-ethoxyaniline, and p-butylaniline. The chromium-based catalyst was Zn / Cr2O3.
[0041] A specific embodiment also provides a conventional silicone emulsion, prepared by the following method:
[0042] Add 3g of hydrophilic emulsifier and 2g of lipophilic emulsifier to 40ml of organosiloxane monomer, then heat to 70-80℃ and stir at 600-900r / min for 3-5min.
[0043] A specific embodiment provides a water-repellent agent that is a mixture of allyltrimethylsilane, polypropylene glycol diglycidyl ether, and ethyl trimethylsilyl ether in a mass ratio of 3:2:5. The water-repellent agent exhibits excellent hydrophobic properties and, when applied to concrete surfaces, can effectively reduce the erosion of contaminants.
[0044] Specifically, the penetrant is one or more of sodium carboxymethyl cellulose and fluorocarbon surfactants. The fluorocarbon surfactant is one of hexafluoroisopropanol and propylene 3,3,3-trifluorocarbonate. The penetrant used has good stability and compatibility, which can effectively improve the penetration depth of the reinforcing agent.
[0045] Specifically, the film-forming aid is one or a mixture of propylene glycol butyl ether and propylene glycol methyl ether acetate. The film-forming aid used has good stability and compatibility, and can effectively improve the hardness and density of the reinforcing agent film, and reduce the penetration of pollutants.
[0046] The silica sol was purchased from Dongguan Huihe Yongsheng Nanotechnology Co., Ltd., specifically Huihe fast-drying silica sol. Unless otherwise specified, all raw materials used in the specific implementation methods were obtained through commercial channels.
[0047] Example 1
[0048] 0.5 parts of propylene glycol butyl ether, 1.5 parts of propylene 3,3,3-trifluorocarbonate, 2 parts of water-repellent agent, and 1.5 parts of silica sol were added to 20 parts of deionized water and dispersed at 300 rpm for 10 min. After stirring evenly, 1 part of mica powder, 0.5 parts of lithium tetrafluoroborate, and 5 parts of refined shell powder were added and dispersed at 1500 rpm for 30 min. Then, 30 parts of modified organosilicon emulsion were added to the evenly stirred mixture and dispersed at 400 rpm for 20 min. Finally, the remaining 20 parts of deionized water were added and stirred evenly to obtain the high-penetration concrete surface enhancer.
[0049] Example 2
[0050] In a beaker, 0.5 parts of propylene glycol methyl ether acetate, 2 parts of hexafluoroisopropanol, 3 parts of water-repellent agent, and 2 parts of silica sol were added to 20 parts of deionized water and dispersed at 300 rpm for 10 min. After stirring evenly, 1 part of talc, 0.5 parts of lithium hexafluorophosphate, and 4 parts of refined shell powder were added and dispersed at 1500 rpm for 30 min. Subsequently, 35 parts of modified organosilicon emulsion were added to the evenly stirred mixture and dispersed at 400 rpm for 20 min. Finally, the remaining 20 parts of deionized water were added and stirred evenly to obtain the high-penetration concrete surface enhancer.
[0051] Example 3
[0052] In a beaker, 1 part propylene glycol butyl ether, 1 part hexafluoroisopropanol, 2 parts water-repellent agent, and 1 part silica sol were added to 10 parts deionized water and dispersed at 300 rpm for 10 min. After stirring evenly, 1 part kaolin, 1 part lithium tetrafluoroborate, and 3 parts refined shell powder were added and dispersed at 1500 rpm for 30 min. Then, 30 parts of self-made modified organosilicon emulsion were added to the evenly stirred mixture and dispersed at 400 rpm for 20 min. Finally, the remaining 20 parts of deionized water were added and stirred evenly to obtain a high-penetration concrete surface enhancer.
[0053] Comparative Example 1
[0054] Repeat Example 1, except that the modified silicone emulsion is replaced with a conventional silicone emulsion, and everything else remains the same.
[0055] Comparative Example 2
[0056] Repeat Example 1, except that the addition of lithium tetrafluoroborate is omitted, and everything else remains the same.
[0057] Comparative Example 3
[0058] Repeat Example 1, but omit the addition of the penetrant, and keep everything else the same.
[0059] The test results of Examples 1-3 and Comparative Examples 1-3 are shown in Table 1.
[0060] Table 1
[0061]
[0062] As shown in Table 1 above, the surface enhancer prepared by the present invention can effectively improve the surface resilience and wear resistance of concrete and reduce chloride ion penetration. As can be seen from Example 1 and Comparative Example 1, the modified organosilicon emulsion can effectively increase the penetration depth of concrete compared with conventional organosilicon emulsion, thereby improving the surface strength of concrete. As can be seen from Comparative Example 2, although the addition of lithium salt cannot increase the penetration depth of concrete, it can effectively improve the surface strength of concrete.
[0063] The above performance characterization method refers to the standard method of "Technical Specification for Testing Compressive Strength of Concrete by Rebound Method" (JGJ / T23-2001) for testing the rebound value of 28-day concrete specimens.
[0064] Durability test: Concrete specimens were cut into pieces with a diameter of 100 mm and a height of 50 mm. The chloride ion permeability of the concrete was tested according to standard GB / T50082-2009 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete". Chloride ion permeability represents the rate at which chloride ions penetrate into the interior of concrete, and is expressed by the chloride ion diffusion coefficient.
[0065] Abrasion resistance test: Abrasion resistance means the abrasion force that a material can withstand when it is worn to a certain depth. The higher the abrasion resistance value, the better the abrasion resistance. Refer to the standard GB / T 16925-1997 "Test method for abrasion resistance of concrete and its products", the specimen size is 100mm×100mm×100mm.
[0066] Penetration depth: After the coated sample is cured, the penetration performance is tested in accordance with the national standard GB / T 18445-2001 "Cement-based penetrating crystalline waterproof coating".
Claims
1. A high-permeability concrete surface enhancer, characterized in that... The composition by weight is as follows: 30-40 parts of modified silicone emulsion; 0.5-1 part silicate; 2-3 parts lithium salt; 3-5 parts shell powder; 1-2 silica sol; 1-2 parts penetrant; 1-2 parts film-forming aid; 2-3 parts water-repellent agent; 30-50 parts deionized water; The preparation method of the modified organosilicon emulsion includes the following steps: (1) Mix organosiloxane monomer, hydrophilic emulsifier, and lipophilic emulsifier and heat to 70-80℃. Stir at 600-900r / min for 3-5min. Continue to add deionized water and polyvinyl alcohol in sequence and stir to disperse evenly to obtain organosilicone pre-emulsion. The mass ratio of organosiloxane monomer, hydrophilic emulsifier, lipophilic emulsifier, deionized water, and polyvinyl alcohol is 40:(1-2):1:(30-40):(5-8). (2) The organic amine solution, isopropoxide titanium solution and the organosilicon pre-emulsion are mixed in a reactor, heated to 40-50℃ at 10-15 MPa, and after adding the chromium-based catalyst, the mixture is mechanically stirred at 200-500 r / min for 2 h. The modified organosilicon emulsion is obtained by filtration. The amount of organic amine, isopropoxide titanium, the organosilicon pre-emulsion and chromium-based catalyst is in the mass ratio of (3-4):7:(20-25):
1.
2. The high-permeability concrete surface enhancer as described in claim 1, characterized in that... The silicate is one or any mixture of mica powder, talc powder, kaolin, and water glass.
3. The high-permeability concrete surface enhancer as described in claim 1, characterized in that... The lithium salt is one or any mixture of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, and lithium perchlorate.
4. The high-permeability concrete surface enhancer as described in claim 1, characterized in that... The particle size of the shell powder is between 1250 mesh and 2000 mesh.
5. The high-permeability concrete surface enhancer as described in claim 1, characterized in that... The silica sol contains 10% to 20% SiO2 by mass and has a particle size of 5 nm to 20 nm.
6. The high-permeability concrete surface enhancer as described in claim 1, characterized in that... The penetrant is one or more of sodium carboxymethyl cellulose or fluorocarbon surfactants.
7. The high-permeability concrete surface enhancer as described in claim 1, characterized in that... The film-forming aid is one or a mixture of propylene glycol butyl ether and propylene glycol methyl ether acetate.
8. The high-permeability concrete surface enhancer as described in claim 1, characterized in that... The hydrophobic agent is a mixture of allyltrimethylsilane, polypropylene glycol diglycidyl ether, and ethyl trimethylsilyl ether in a mass ratio of 3:2:
5.
9. The method for preparing the high-permeability concrete surface enhancer according to claim 1, characterized in that... Includes the following steps: The film-forming aid, penetrant, hydrophobic agent and silica sol were mixed and dispersed evenly in a portion of deionized water; Add silicate, lithium salt and shell powder in sequence and stir until well mixed; Finally, the modified silicone emulsion and the remaining deionized water are added and mixed evenly to obtain the high-penetration concrete surface enhancer.