A concrete zero-interval polyurethane curing protection reinforcement material and preparation method thereof

Abstract

The present invention relates to a concrete zero-interval polyurethane curing and protective reinforcement material and a preparation method thereof. The reinforcement material sequentially comprises: an adhesive layer with controllable strength attenuation, a curing and protective layer, and a concrete bonding layer; the reinforcement material forms an integral body with a concrete forming steel formwork through the adhesive layer, and the joints between the adhesive layer, the curing and protective layer, and the concrete layer are mutually fused into a non-layered integral body; wherein the curing and protective layer comprises the following components by weight: 80-100 parts of a polyurethane light-curing resin, 0.2-0.8 parts of a photoinitiator, 20-25 parts of a diluent, and 3-5 parts of surface-modified nano-silicon dioxide; the concrete bonding layer comprises ultrafine magnesium oxychloride cement; the adhesive has an initial bonding strength of 1.2 MPa, capable of bonding the curing and protective layer and the concrete forming steel formwork; and over time, its bonding strength decreases to 0.05 MPa, enabling separation from the concrete forming steel formwork.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete curing, and in particular to a concrete zero-interval polyurethane curing protection reinforcement material and a preparation method thereof. Background Art

[0002] Cement concrete is the world's most widely used composite material, widely used in various projects. Proper early curing, ensuring sufficient moisture for hydration, is a key control step in ensuring the quality of concrete projects. It can significantly improve concrete's durability, strength, wear resistance, and volume stability.

[0003] During concrete construction, the concrete must first be cured in formwork. After a period of curing, the formwork must be removed. Even after formwork removal, the concrete still needs to be damp-cured. The traditional method for curing concrete after formwork removal is to quickly cover the concrete surface with plastic film or a composite film containing a water-absorbing resin while it is still damp, or to spray the concrete surface with water.

[0004] However, all of the above methods will cause the concrete to be exposed to the atmospheric environment for a certain period of time after demolding, which can easily cause cracking; the method of sprinkling water or wrapping it with a curing film is labor-intensive and increases the burden on construction workers; in addition, the wrapped curing film can easily be blown away by strong winds and lose its curing effect, and it is easy to cause environmental pollution when removing the curing film. Moreover, the construction efficiency is low and risks are prone to occur when removing the curing film on the concrete surface of high piers. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a concrete zero-interval polyurethane curing and protection reinforcement material and a preparation method thereof.

[0006] In order to solve the above problems, the technical solution adopted by the present invention is:

[0007] A concrete zero-interval polyurethane curing and protective reinforcement material, which can be a concrete zero-interval polyurethane curing and protective reinforcement prefabricated component, sequentially comprises: an adhesive layer with controllable strength attenuation, a curing and protective layer, and a concrete bonding layer; the adhesive layer forms a whole with a steel formwork for concrete forming through the adhesive layer; the joints between the adhesive layer, the curing and protective layer, and the concrete layer are fused together to form a non-layered whole;

[0008] The curing and protective layer comprises the following components by weight: 80-100 parts of polyurethane light-curing resin, 0.2-0.8 parts of photoinitiator, 20-25 parts of diluent, and 3-5 parts of surface-modified nano-silicon dioxide;

[0009] The concrete bonding layer is composed of ultrafine magnesium oxychloride cement;

[0010] The adhesive has an initial bond strength of 1.2 MPa, sufficient to bond the protective layer to the concrete steel formwork. Over time, the bond strength decreases to 0.05 MPa, allowing separation from the concrete steel formwork. Preferably, the bond strength is 0.05 MPa 6 hours after concrete pouring.

[0011] As an embodiment of the invention, the thickness of the adhesive layer is 20-50 microns, and the thickness of the maintenance and protection layer is 50-80 microns.

[0012] As an embodiment of the invention, the spreading amount of the ultrafine magnesium oxychloride cement is 100-300g / m 2 .

[0013] As an embodiment of the invention, the polyurethane light-curing resin is a mixture of difunctional polyurethane acrylate and hexafunctional polyurethane acrylate in a ratio of 10-25:2-3.

[0014] As an embodiment of the invention, the photoinitiator is a mixture of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl benzophenone, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide in a ratio of 10-20:30-50:1-3.

[0015] As an embodiment of the invention, the diluent is a pentaerythritol derivative, and the molecular structure is: .

[0016] As an embodiment of the invention, the surface-modified nano-silica is modified nano-silica containing double bonds on its surface.

[0017] As an embodiment of the invention, the particle size of the ultrafine magnesium oxychloride cement is 30-800 microns.

[0018] In a second aspect, a method for preparing the concrete zero-interval polyurethane curing and protective reinforcement material according to the first aspect is provided, the method comprising:

[0019] By weight, 80-100 parts of polyurethane light-curing resin, 0.2-0.8 parts of photoinitiator, 20-25 parts of diluent, and 3-5 parts of surface-modified nano-silica are mixed at room temperature to obtain a mixture A;

[0020] A 20-50 micron thick adhesive with controllable attenuation of bonding strength is sprayed on the inner surface of each concrete forming steel formwork. Then, a 50-80 micron thick mixture A is applied to the surface of the adhesive. Then, ultrafine magnesium oxychloride cement is applied to the surface of the mixture A to obtain mixture B.

[0021] Irradiate mixture B with 300-350 nm UV light for 30-60 s;

[0022] After assembling the steel formwork, watering the mixture B on each of the concrete forming steel formworks to cause a chemical reaction between the particles in the mixture A to form a curing and protective layer;

[0023] A humidity sensor with wireless transmission function is embedded 2-3 cm away from the formwork, and then concrete is poured. After the concrete is cured for 7 days, the formwork is removed, the adhesive is separated from the steel formwork used for concrete molding, and the polyurethane curing and protection reinforcement material is obtained on the concrete surface.

[0024] The initial bonding strength of the adhesive is 1.2 MPa, which can bond the protective layer and the steel formwork for concrete molding. As time goes by and the formwork is removed after 7 days of curing, its bonding strength is 0.05 MPa, which can separate it from the steel formwork for concrete molding.

[0025] In a third aspect, a method is provided for applying the concrete zero-interval polyurethane curing protection reinforcement material as described in the first aspect in concrete curing.

[0026] The beneficial effects of adopting the above technical solution are:

[0027] The concrete zero-interval polyurethane curing and protection reinforcement material and the preparation method thereof provided by the present invention are provided with three layers of reinforcement material: an adhesive layer, a curing and protection layer and a concrete bonding layer.

[0028] By setting up an adhesive with controllable strength attenuation, its strong initial bonding strength can ensure that the concrete can be bonded to the concrete forming formwork during the pouring and curing process, and the bonding strength can be automatically reduced when the curing time is reached, which facilitates the demolding of the formwork; in addition, after demolding, the reinforcing material always covers the surface of the concrete, and the concrete will not be exposed to the atmospheric environment, truly achieving zero intermittency.

[0029] By setting ultrafine magnesium oxychloride cement as the concrete bonding layer, it can form high strength with the poured concrete, and the strength after bonding is high, and it will not fall off or delaminate.

[0030] In addition, by setting the formula components: 80-100 parts of polyurethane photocurable resin, 0.2-0.8 parts of photoinitiator, 20-25 parts of diluent, and 3-5 parts of surface-modified nano-silica, under the synergistic effect of the four, a dense curing and protective layer can be formed by short-term irradiation of ultraviolet light. The preparation method is simple, the curing speed is fast, the performance is stable, the strength after molding is high, it does not fall off, does not delaminate, and is highly practical.

[0031] In addition, the reinforcing material provided by the present invention covers the surface of the concrete, and has high strength after bonding with the poured concrete, will not fall off or delaminate, and will not be blown away even in a windy and dry environment. It can effectively avoid cement cracking caused by rapid evaporation of water, improve maintenance efficiency, and do not require construction workers to perform subsequent maintenance operations, thereby reducing the burden on construction workers. Moreover, the reinforcing material can protect the concrete surface from direct sunlight and wind and sand erosion, thereby playing a protective role. Moreover, the concrete surface rebound strength obtained after 14 days can be as high as 34.2 MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a production process roadmap for a zero-interval polyurethane curing and protective reinforcement material for concrete provided by the present invention.

[0033] Figure 2 It is a structural schematic diagram of concrete provided by the present invention, the surface of which is provided with the polyurethane curing and protection reinforcement material.

[0034] Figure 3 Schematic diagram of the cumulative pore volume of concrete obtained in Example 2 and Comparative Example 5.

[0035] Figure 4 Schematic diagram of the differential pore volume of the concrete obtained in Example 2 and Comparative Example 5.

[0036] Among them, 1- steel formwork for concrete forming, 2- adhesive layer, 3- curing and protective layer, 4- concrete bonding layer. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present invention more clear, the invention is clearly and completely described below in conjunction with specific embodiments.

[0038] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0039] An adhesive with controllable attenuation of bonding strength is prepared with reference to the invention patent publication number CN 111286295 A;

[0040] Difunctional polyurethane acrylate, DIC Synthetic Resin (Zhongshan) Co., Ltd.

[0041] Hexafunctional polyurethane acrylate, DIC Synthetic Resins (Zhongshan) Co., Ltd.

[0042] 2-Hydroxy-2-methyl-1-phenylpropanone, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0043] 1-Hydroxycyclohexylbenzophenone, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0044] 2,4,6-Trimethylbenzoyldiphenylphosphine oxide, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0045] Pentaerythritol derivatives, Chifeng Ruiyang Chemical Co., Ltd.;

[0046] Modified nano-silica with double bonds on the surface, Nanjing Hitech Nanomaterials Co., Ltd.;

[0047] Ultrafine magnesium oxychloride cement, Dongguan Deepsea Energy Saving Building Materials Technology Co., Ltd.

[0048] Example 1

[0049] (1) Preparation of mixture A1

[0050] The polyurethane light-curing resin is obtained by mixing difunctional polyurethane acrylate and hexafunctional polyurethane acrylate in a ratio of 10:3 by weight;

[0051] 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl benzophenone, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide are mixed in a ratio of 10:30:1 to obtain a photoinitiator;

[0052] Weigh 80 parts of polyurethane light-curable resin, 0.2 parts of photoinitiator, 20 parts of pentaerythritol derivative, and 3 parts of modified nano-silica with double bonds on the surface, and mix them uniformly at room temperature to obtain a mixture A;

[0053] (2) Spray a 20 μm thick adhesive with controlled attenuation of bonding strength (the initial bonding strength of the adhesive is 1.2 MPa) on the inner surface of each concrete forming steel formwork; then, apply a 50 μm thick mixture A1 on the adhesive surface, and then apply a 100 g / m2 thick mixture A1 on the surface of the mixture A. 2 Apply ultrafine magnesium oxychloride cement to obtain mixture B1;

[0054] (3) Irradiate mixture B1 with 350nm ultraviolet light for 30s, so that a chemical reaction occurs between the particles in mixture A to form a curing protective layer;

[0055] (4) After assembling the steel formwork, water the mixture B on each of the concrete forming steel formworks to moisten the surface of the magnesium oxychloride cement;

[0056] (5) A humidity sensor with wireless transmission function was embedded 1 cm away from the formwork, and then concrete was poured. After the concrete was cured for 7 days, the formwork was removed. The bonding strength of the adhesive had decreased to about 0.05 MPa and it would separate from the curing protective layer, resulting in concrete C1 with polyurethane curing protective reinforcement material on the surface.

[0057] The preparation principle is as follows Figure 1 As shown, the obtained concrete C1 structure is as follows Figure 2 shown.

[0058] Example 2

[0059] (1) Preparation of mixture A2

[0060] The polyurethane light-curing resin is obtained by mixing difunctional polyurethane acrylate and hexafunctional polyurethane acrylate in a ratio of 17:3 by weight;

[0061] 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl benzophenone, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide are mixed in a ratio of 16:45:2 to obtain a photoinitiator;

[0062] Weigh 86 parts of polyurethane light-curable resin, 0.6 parts of photoinitiator, 23 parts of pentaerythritol derivative, and 4 parts of modified nano-silica with double bonds on the surface, and mix them uniformly at room temperature to obtain mixture A2;

[0063] (2) Spray a 40 μm thick adhesive with controlled attenuation of bonding strength (the initial bonding strength of the adhesive is 1.2 MPa) on the inner surface of each concrete forming steel formwork. Then, apply a 70 μm thick mixture A2 on the surface of the adhesive. Then, apply a 220 g / m thick mixture A2 on the surface of the mixture A. 2 Applying ultrafine magnesium oxychloride cement yields mixture B2;

[0064] (3) Irradiate mixture B2 with 320 nm ultraviolet light for 45 s, causing a chemical reaction between the particles in mixture A to form a protective layer;

[0065] (4) After assembling the steel formwork, water the mixture B on each of the concrete forming steel formworks to moisten the surface of the magnesium oxychloride cement;

[0066] (5) A humidity sensor with wireless transmission function was embedded at a distance of 0.5 cm from the formwork, and then concrete was poured. After the concrete was cured for 7 days, the formwork was removed. The bonding strength of the adhesive had decreased to about 0.05 MPa and it would separate from the curing protective layer, resulting in concrete C2 with polyurethane curing protective reinforcement material on the surface.

[0067] The preparation principle is as follows Figure 1 As shown, the obtained concrete C1 structure is as follows Figure 2 shown.

[0068] Example 3

[0069] (1) Preparation of mixture A3

[0070] The polyurethane light-curing resin is obtained by mixing difunctional polyurethane acrylate and hexafunctional polyurethane acrylate in a ratio of 25:3 by weight;

[0071] 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl benzophenone, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide are mixed in a ratio of 20:50:3 to obtain a photoinitiator;

[0072] Weigh 100 parts of polyurethane light-curable resin, 0.8 parts of photoinitiator, 25 parts of pentaerythritol derivative, and 5 parts of modified nano-silica with double bonds on the surface, and mix them uniformly at room temperature to obtain a mixture A3;

[0073] (2) Spray 50 microns of adhesive with controlled attenuation of bonding strength (the initial bonding strength of the adhesive is 1.2 MPa) on the inner surface of each concrete forming steel formwork. Then, apply 80 microns of mixture A3 on the surface of the adhesive. Then, apply 300 g / m2 of mixture A3 on the surface of mixture A. 2 Applying ultrafine magnesium oxychloride cement yields mixture B3;

[0074] (3) Irradiate mixture B3 with 300 nm ultraviolet light for 60 s, causing a chemical reaction between the particles in mixture A to form a protective layer;

[0075] (4) After assembling the steel formwork, water the mixture B on each of the concrete forming steel formworks to moisten the surface of the magnesium oxychloride cement;

[0076] (5) A humidity sensor with wireless transmission function was embedded 1.5 cm away from the formwork, and then concrete was poured. After the concrete was cured for 7 days, the formwork was removed. The bonding strength of the adhesive had decreased to about 0.05 MPa and it would separate from the curing protective layer, resulting in concrete C3 with polyurethane curing protective reinforcement material on the surface.

[0077] The preparation principle is as follows Figure 1 As shown, the obtained concrete C1 structure is as follows Figure 2 shown.

[0078] Comparative Example 1

[0079] (1) Preparation of mixture A4

[0080] The polyurethane light-curing resin is obtained by mixing difunctional polyurethane acrylate and hexafunctional polyurethane acrylate in a ratio of 17:3 by weight;

[0081] 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl benzophenone, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide are mixed in a ratio of 16:45:2 to obtain a photoinitiator;

[0082] Weigh 86 parts of polyurethane light-curable resin, 0.6 parts of photoinitiator, 23 parts of pentaerythritol derivative, and 4 parts of modified nano-silica with double bonds on the surface, and mix them uniformly at room temperature to obtain a mixture A;

[0083] (2) Apply 70 microns of mixture A4 to the inner surface of each concrete forming steel formwork, and then apply 220g / m 2 Apply ultrafine magnesium oxychloride cement to obtain mixture B4;

[0084] (3) Irradiate mixture B4 with 320 nm ultraviolet light for 45 s, causing a chemical reaction between the particles in mixture A4 to form a curing protective layer;

[0085] (4) After assembling the steel formwork, water the mixture B on each of the concrete forming steel formworks to moisten the surface of the magnesium oxychloride cement;

[0086] (5) A humidity sensor with wireless transmission function was embedded 0.5 cm away from the formwork, and then concrete was poured. After the concrete was cured for 7 days, the formwork was removed to obtain concrete C4.

[0087] Comparative Example 2

[0088] (1) Preparation of mixture A5

[0089] The polyurethane light-curing resin is obtained by mixing difunctional polyurethane acrylate and hexafunctional polyurethane acrylate in a ratio of 17:3 by weight;

[0090] 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl benzophenone, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide are mixed in a ratio of 16:45:2 to obtain a photoinitiator;

[0091] Weigh 86 parts of polyurethane light-curable resin, 0.6 parts of photoinitiator, 23 parts of pentaerythritol derivative, and 4 parts of modified nano-silica with double bonds on the surface, and mix them uniformly at room temperature to obtain mixture A5;

[0092] (2) Spray a 40 μm thick adhesive with controlled attenuation of bonding strength (the initial bonding strength of the adhesive is 1.2 MPa) on the inner surface of each concrete forming steel formwork; then, apply a 70 μm thick mixture A5 on the surface of the adhesive, and then apply a 220 g / m 2 Apply ultrafine Portland cement to obtain mixture B5;

[0093] (3) Irradiate mixture B5 with 320 nm ultraviolet light for 45 s, causing a chemical reaction between the particles in mixture A to form a protective layer;

[0094] (4) After assembling the steel formwork, watering the mixture B on each of the concrete forming steel formworks;

[0095] (5) A humidity sensor with wireless transmission function was embedded 0.5 cm away from the formwork, and then concrete was poured. After the concrete was cured for 7 days, the formwork was removed. The bonding strength of the adhesive had decreased to about 0.05 MPa and it would separate from the curing protective layer, resulting in concrete C5.

[0096] Comparative Example 3

[0097] (1) Preparation of mixture A6

[0098] A photoinitiator is prepared by mixing 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl benzophenone, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide in a ratio of 16:45:2 by weight;

[0099] Weigh 86 parts of difunctional polyurethane acrylate, 0.6 parts of photoinitiator, 23 parts of pentaerythritol derivative, and 4 parts of modified nano-silica containing double bonds on the surface, and mix them uniformly at room temperature to obtain mixture A6;

[0100] (2) Spray a 40 μm thick adhesive with controlled attenuation of bonding strength (the initial bonding strength of the adhesive is 1.2 MPa) on the inner surface of each concrete forming steel formwork. Then, apply a 70 μm thick mixture A6 on the surface of the adhesive. Then, apply a 220 g / m2 adhesive on the surface of the mixture A6. 2 Applying ultrafine magnesium oxychloride cement yields mixture B6;

[0101] (3) Irradiate the mixture B6 with 320 nm UV light for 45 s;

[0102] (4) After assembling the steel formwork, water the mixture B on each of the concrete forming steel formworks to moisten the surface of the magnesium oxychloride cement;

[0103] (5) A humidity sensor with wireless transmission function was embedded 0.5 cm away from the formwork, and then concrete was poured. After the concrete was cured for 7 days, the formwork was removed. The bonding strength of the adhesive had decreased to about 0.05 MPa and separated from the curing protective layer, resulting in concrete C6.

[0104] Comparative Example 4

[0105] (1) Preparation of mixture A7

[0106] The polyurethane light-curing resin is obtained by mixing difunctional polyurethane acrylate and hexafunctional polyurethane acrylate in a ratio of 17:3 by weight;

[0107] Weigh 86 parts of polyurethane light-curing resin, 0.6 parts of 2-hydroxy-2-methyl-1-phenylacetone, 23 parts of a pentaerythritol derivative, and 4 parts of modified nano-silica having double bonds on its surface, and mix them uniformly at room temperature to obtain a mixture A7;

[0108] (2) Spray a 40 μm thick adhesive with controlled attenuation of bonding strength (the initial bonding strength of the adhesive is 1.2 MPa) on the inner surface of each concrete forming steel formwork. Then, apply a 70 μm thick mixture A7 on the surface of the adhesive. Then, apply a 220 g / m2 adhesive on the surface of the mixture A7. 2 Applying ultrafine magnesium oxychloride cement yields mixture B7;

[0109] (3) Irradiate the mixture B7 with 320 nm UV light for 45 s;

[0110] (4) After assembling the steel formwork, water the mixture B7 on each of the concrete forming steel formworks to moisten the surface of the magnesium oxychloride cement;

[0111] (5) A humidity sensor with wireless transmission function was embedded 0.5 cm away from the formwork, and then concrete was poured. After the concrete was cured for 7 days, the formwork was removed. The bonding strength of the adhesive had decreased to about 0.05 MPa and it would separate from the curing protective layer, resulting in concrete C7.

[0112] Comparative Example 5

[0113] After assembling the steel formwork, concrete was poured into the concrete forming steel formwork. After curing for 7 days, the formwork was removed to obtain concrete C8.

[0114] Effect example:

[0115] (1) Surface rebound strength test

[0116] Concretes C1-C7 obtained in Examples 1-3 and Comparative Examples 1-4 were directly placed in a high-wind, dry environment (wind force 7 or higher, humidity below 20%). Concrete C8 obtained in Comparative Example 5 had a portion of its surface covered with plastic film and then placed in a high-wind, dry environment (C81), while a portion was directly placed in a high-wind, dry environment (C82). After 7 days (i.e., 14 days of curing), the surface rebound strength of each of Concrete C1-C8 was measured at 30 locations using a concrete test hammer. The results are shown in Table 1.

[0117] Table 1 Comparison of rebound strength after 14 days

[0118]

[0119] As can be seen from Table 1, regardless of whether traditional curing or the zero-interval curing of the present invention is adopted, the average value of the concrete surface rebound strength obtained is higher than the surface rebound strength value of the concrete without curing (23.7 MPa), indicating that both have obvious curing effects.

[0120] In addition, the average surface rebound strength of the concrete obtained by adopting the solution of the embodiment of the present invention is above 33.5 MPa, which is significantly higher than the average surface rebound strength of the concrete subjected to traditional curing (29.2 MPa), indicating that the zero-interval curing of the present invention can further improve material properties.

[0121] In addition, the average surface rebound strength dropped to 25.7 MPa after the adhesive layer was missing. The reason is that after removing the adhesive bonding, the curing and protective layer may not completely fall off from the steel formwork during demolding, thus losing the curing and protective effect; after the ultrafine magnesium oxychloride cement was changed to silicate cement, the bonding strength between it and the concrete was reduced and it could not be firmly bonded to the concrete. In a windy and dry environment, it is easy for part of the concrete to be exposed for curing due to peeling, falling, etc., thus affecting the average surface rebound strength; after changing the formula of the curing and protective layer, the average concrete surface rebound strength decreased, indicating that the curing and protection effect has deteriorated.

[0122] (2) Humidity test

[0123] The humidity at 0.5 cm from the concrete surface was tested by a humidity sensor embedded in the concrete C2 obtained in Example 2 for 1 to 14 days of curing. The results showed that the humidity value was greater than 95% within 14 days of curing; and no cracks were observed on the concrete surface.

[0124] (3) Gas permeability coefficient and surface resistance test

[0125] After the concrete C2 obtained in Example 2 and the concrete C8 obtained in Comparative Example 5 were cured for 14 days, the gas permeability coefficient and surface resistance of the concrete were tested using a concrete gas permeability tester and a concrete surface resistivity tester, respectively.

[0126] The surface gas permeability coefficient of concrete C2 obtained in Example 2 was measured to be 0.08×10 -16 m 2 , the surface resistance is 48.7MΩ; the surface gas permeability coefficient of conventionally cured concrete (C81) is 0.29×10 -16 m 2 , the surface resistance is 32MΩ.

[0127] (4) Pore volume test

[0128] After the concrete C2 obtained in Example 2 and the concrete C8 obtained in Comparative Example 5 were cured for 14 days, the cumulative pore volume and differential pore volume of the surface concrete of the two were tested using a mercury intrusion porosimeter. The results are as follows: Figure 3 and Figure 4 shown.

[0129] Depend on Figure 3 and Figure 4 It can be seen that the pore size of the conventionally cured surface concrete C81 is about 100 nm, while the pore size of the surface concrete C2 obtained in Example 2 is reduced to about 20 nm.

[0130] Therefore, compared with traditional curing, the concrete surface gas permeability coefficient obtained in Example 2 is low, the surface resistance is large, and the surface concrete density is higher; and its pore size is only about 20 cm, so the surface performance is better.

Claims

1. A concrete zero-interval polyurethane curing and protection reinforcement material, characterized in that: The invention comprises, in sequence: an adhesive layer with controllable strength attenuation, a curing and protective layer, and a concrete bonding layer; the adhesive layer forms a whole with the steel formwork for concrete forming through the adhesive layer, and the joints between the adhesive layer, the curing and protective layer, and the concrete bonding layer are fused into a non-layered whole; The curing and protective layer comprises the following components by weight: 80-100 parts of a polyurethane light-curing resin, 0.2-0.8 parts of a photoinitiator, 20-25 parts of a diluent, and 3-5 parts of surface-modified nano-silica; the polyurethane light-curing resin is a mixture of a difunctional polyurethane acrylate and a hexafunctional polyurethane acrylate in a ratio of 10-25:2-3; the photoinitiator is a mixture of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl benzophenone, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide in a ratio of 10-20:30-50:1-3; the diluent is a pentaerythritol derivative, and the molecular structure is: ; The surface-modified nano-silica is modified nano-silica containing double bonds on the surface; The concrete bonding layer is composed of ultrafine magnesium oxychloride cement; The adhesive layer has an initial bonding strength of 1.2 MPa, capable of bonding the protective layer and the concrete forming steel formwork; as time goes by, its bonding strength decreases to 0.05 MPa, capable of separating from the concrete forming steel formwork; The preparation method of the concrete zero-interval polyurethane curing protection reinforcement material comprises: Spray adhesive on the inner surface of each concrete forming steel formwork, then apply a curing and protective layer component on the adhesive surface, and then apply ultrafine magnesium oxychloride cement on it; Irradiating with ultraviolet light causes a chemical reaction between the components of the curing and protective layer to form the curing and protective layer; The steel formwork is sprinkled with water after assembly.

2. The concrete zero-interval polyurethane curing and protection reinforcement material according to claim 1, characterized in that: The thickness of the adhesive layer is 20-50 microns, and the thickness of the maintenance and protection layer is 50-80 microns.

3. The concrete zero-interval polyurethane curing and protection reinforcement material according to claim 1, characterized in that: The spreading amount of the ultrafine magnesium oxychloride cement is 100-300g / m 2 .

4. The concrete zero-interval polyurethane curing and protection reinforcement material according to claim 1, characterized in that: The particle size of the ultrafine magnesium oxychloride cement is 30-800 microns.

5. A method for preparing the concrete zero-interval polyurethane curing and protection reinforcement material according to any one of items 1 to 4, characterized in that: The method comprises: By weight, 80-100 parts of polyurethane light-curing resin, 0.2-0.8 parts of photoinitiator, 20-25 parts of diluent, and 3-5 parts of surface-modified nano-silica are mixed at room temperature to obtain a mixture A; Spraying a 20-50 micron thick adhesive with controllable attenuation of bonding strength on the inner surface of each concrete forming steel formwork, then brushing a 50-80 micron thick mixture A on the adhesive surface, and then applying ultrafine magnesium oxychloride cement on the surface of mixture A to obtain mixture B; Irradiate mixture B with 300-350 nm UV light for 30-60 s; After assembling the steel formwork, watering the mixture B on each of the concrete forming steel formworks to cause a chemical reaction between the particles in the mixture A to form a curing and protective layer; A humidity sensor with wireless transmission function is embedded 0.5-1.5 cm away from the template, and then concrete is poured. After the concrete is cured for 7 days, the template is removed, the adhesive is separated from the steel template used for concrete molding, and the polyurethane curing protection reinforcement material is obtained on the concrete surface.

6. Use of the concrete zero-interval polyurethane curing protection reinforcement material according to any one of claims 1 to 4 in concrete curing.

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