Preparation method and application of cement-based composite phase change grouting material

Abstract

This invention belongs to the field of grouting material technology, specifically relating to a preparation method and application of a cement-based composite phase change grouting material. The cement-based composite phase change grouting material is made from the following raw material components: silicate cement, sand and gravel aggregate, fiber reinforcement, water-reducing agent, phase change material, fly ash, and water. The preparation method includes the following steps: First, weigh each raw material component separately and prepare them; Second, add each raw material to a mixer, start stirring, and control the stirring speed at 500 r / min to 1000 r / min. After mechanically mixing evenly, discharge the material to obtain the cement-based composite phase change grouting material. This invention effectively improves the compatibility between the phase change material and the cement-based material, thereby avoiding obvious defects and weak points around the phase change material, effectively improving the thermal conductivity of the cement grouting material and enhancing its heat storage performance.

Description

Technical Field

[0001] This invention belongs to the field of grouting materials technology, specifically relating to a method for preparing and applying a cement-based composite phase change grouting material. Background Technology

[0002] In the field of civil engineering, grouting materials are widely used in foundation reinforcement, crack repair, tunnel support, and other applications. Traditional cement-based grouting materials are widely used due to their low cost and mature technology. However, with the increasing complexity of engineering environments and the upgrading of functional requirements, existing technologies face numerous technical bottlenecks. First, traditional cement-based materials are brittle and have low toughness after curing, making them prone to cracking under temperature cycles or freeze-thaw cycles, leading to the separation of the grout from the bedrock / structure interface. For example, in tunnels in cold regions or seasonally frozen soil projects, volumetric deformation caused by temperature fluctuations can significantly reduce the service life of the materials.

[0003] To address these issues, early attempts involved incorporating phase change materials (PCMs) such as paraffin wax and fatty acids into cementitious matrices. These PCMs undergo phase changes at specific temperatures, storing or releasing heat, exhibiting high heat storage density and isothermal phase change processes. However, directly combining PCMs with cementitious materials leads to problems such as low strength, volume changes, and decreased heat storage performance. Therefore, encapsulation technologies such as impregnation adsorption, shaping encapsulation, and capsule encapsulation have been employed to improve compatibility and stability. Among these methods, capsule encapsulation is relatively simpler in process and offers better encapsulation results, thus its application is more widespread. However, existing capsule encapsulation methods generally have complex preparation processes and are relatively difficult to operate, making practical application challenging. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing cement-based composite phase change grouting material, thereby improving the physical and chemical properties of cement grouting material, such as mechanical strength, crack resistance, and heat storage performance.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a cement-based composite phase change grouting material, wherein the cement-based composite phase change grouting material is prepared from raw material components comprising the following parts by weight:

[0007] 45-55 parts silicate cement, 60-75 parts sand and gravel aggregate, 4-6 parts fiber reinforcement, 1-3 parts water-reducing agent, 8-15 parts phase change material, 5-10 parts fly ash, and 40-50 parts water.

[0008] The preparation method includes the following steps:

[0009] Step 1: Weigh each raw material component separately and prepare them.

[0010] The second step is to add all the raw materials into the mixer, start the mixer, and control the mixing speed to 500r / min~1000r / min. After the mechanical mixing is uniform, the material is discharged to obtain the cement-based composite phase change grouting material.

[0011] In a preferred embodiment, the method for preparing the fiber reinforcement material includes the following steps:

[0012] Step 1: Use epoxy silane coupling agent as a surface modifier to modify the surface of glass fiber to obtain functionalized modified glass fiber.

[0013] Step 2: The functionalized modified glass fiber is ultrasonically dispersed in N,N-dimethylformamide medium to form a uniform dispersion. Then, aspartic acid is added to the dispersion, the temperature is raised to 70℃~80℃, and the mixture is stirred for 3h~6h. Then, benzidine disulfonic acid and catalyst are added to the dispersion. After the addition is complete, the temperature is further raised to 120℃~130℃, and the mixture is stirred for 12h~18h. Then, the heating is stopped, the material is cooled and discharged, and the solid material is separated and collected to obtain the fiber-reinforced material.

[0014] In a preferred example, the epoxy silane coupling agent is selected from 3-glycidyl etheroxytrimethoxysilane or 3-glycidyl etheroxytriethoxysilane.

[0015] In a preferred example, the mass ratio of the functionalized modified glass fiber, aspartic acid, and benzidine disulfonic acid is 1:1.5 to 2:1 to 1.8.

[0016] In a preferred example, the catalyst is selected from aminosulfonic acid or p-toluenesulfonic acid.

[0017] In a preferred embodiment, the water-reducing agent is selected from polycarboxylate water-reducing agents or naphthalene-based water-reducing agents.

[0018] In a preferred embodiment, the method for preparing the phase change material includes the following steps:

[0019] Step S1: After heating the solid paraffin until it is completely melted, add the liquid paraffin and stir and mix it evenly at a temperature of 50℃~55℃ to form paraffin oil. Then, impregnate the expanded vermiculite in the paraffin oil and sonicate it at an ultrasonic frequency of 80kHz~100kHz for 1h~2h. Then filter it until no more paraffin is filtered out and collect the solid material to form the precursor material.

[0020] Step S2: Disperse the precursor material in purified water, then add carboxymethyl starch and crosslinking agent to the formed dispersion, treat it in a temperature environment of 60℃~70℃ for 2h~4h, cool down and discharge the material, separate the solid material, and the phase change material can be obtained.

[0021] In a preferred example, the crosslinking agent is selected from sodium tripolyphosphate or sodium trimetaphosphate.

[0022] In a preferred embodiment, the fly ash is selected from either Grade I fly ash or Grade II fly ash.

[0023] Based on a general inventive concept, another object of the present invention is to provide the application of the cement-based composite phase change grouting material prepared by the above-described method in the field of building insulation.

[0024] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0025] (1) The present invention first modifies the surface of glass fiber by using an epoxy silane coupling agent to obtain glass fiber with epoxy groups on the surface, thus obtaining functionalized modified glass fiber. Then, aspartic acid is used to further modify it. Under the action of high temperature and catalyst, aspartic acid and benzidine disulfonic acid will polymerize in situ on the surface of glass fiber to form glass fiber with macromolecular modifier on the surface. Since the macromolecular modifier contains a large number of sulfonic acid groups, these sulfonic acid groups can interact with cement hydration products, thereby promoting the bonding between glass fiber and cement matrix, improving the bonding force between them, and thus efficiently utilizing the reinforcing effect of glass fiber to improve the mechanical strength and crack resistance of cement grouting material.

[0026] (2) In this invention, expanded vermiculite is used as a coating material to encapsulate paraffin. Under ultrasonic conditions, paraffin can break through the interlayer barrier of expanded vermiculite and enter the interlayer of vermiculite for storage. Then, carboxymethyl starch and crosslinking agent are used to crosslink and coat the surface of expanded graphite to prevent paraffin from seeping out under high pressure in the later stage of hydration. In addition, the carboxymethyl group in the structure of carboxymethyl starch will also interact with the hydration products of cement, thereby effectively improving the compatibility between phase change material and cement base material, thus avoiding obvious defects and weak points around the phase change material, effectively improving the thermal conductivity of cement grouting material and enhancing its heat storage performance. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is further described in conjunction with specific embodiments. However, this invention is not limited to these embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments. In this invention, unless otherwise specified, all parts and percentages are units of mass, and the equipment and raw materials used are commercially available or commonly used in the art. Unless otherwise specified, the methods in the following embodiments are conventional methods in the art.

[0028] The terms “comprising,” “including,” “containing,” or any other variations thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0029] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1 to 5” is disclosed, the described range should be interpreted as including the ranges “1 to 4”, “1 to 3”, “1 to 2”, “1 to 2 and 4 to 5”, “1 to 3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0030] Example 1

[0031] A cement-based composite phase change grouting material is made from raw material components comprising the following parts by weight:

[0032] 45 parts silicate cement, 60 parts sand and gravel aggregate, 4 parts fiber reinforcement, 1 part water-reducing agent, 8 parts phase change material, 5 parts Class I fly ash, and 40 parts water.

[0033] The preparation method of the cement-based composite phase change grouting material includes the following steps:

[0034] Step 1: Weigh each raw material component separately and prepare them.

[0035] The second step is to add all the raw materials into the mixer, turn on the mixer, control the mixing speed to 500 r / min, and after mechanical mixing is uniform, discharge the material to obtain cement-based composite phase change grouting material.

[0036] The method for preparing the fiber-reinforced material includes the following steps:

[0037] Step 1: 1.2g of glass fiber is ultrasonically dispersed in 70% ethanol by volume, followed by the addition of 2.5g of 3-glycidyl etheroxytriethoxysilane. After the addition is complete, the temperature is raised to 75℃ and kept at that temperature for 6 hours. Then, the material is cooled and discharged to obtain functionalized modified glass fiber.

[0038] Step 2: 1.6g of functionalized modified glass fiber was ultrasonically dispersed in N,N-dimethylformamide medium to form a uniform dispersion. Then, 3g of aspartic acid was added to the dispersion, the temperature was raised to 75℃, and the mixture was stirred for 4 hours. Then, 2.5g of benzidine disulfonic acid and 0.1g of p-toluenesulfonic acid were added to the dispersion. After the addition was complete, the temperature was further raised to 125℃, and the mixture was stirred continuously for 16 hours. Then, the heating was stopped, the material was cooled and discharged, and the solid material was separated and collected to obtain the fiber-reinforced material.

[0039] The method for preparing the phase change material includes the following steps:

[0040] Step S1: Heat 1g of solid paraffin until it is completely melted, add 0.5g of liquid paraffin, stir and mix evenly at 50°C to form paraffin oil, then impregnate 0.1g of expanded vermiculite in the paraffin oil, sonicate at 100kHz for 2 hours, filter, and collect the solid material after no more paraffin is filtered out to form the precursor material.

[0041] Step S2: Disperse 0.5g of precursor material in purified water, then add 1.8g of carboxymethyl starch and 0.2g of sodium tripolyphosphate to the resulting dispersion. After treating at 65°C for 3 hours, cool down and discharge the material to separate the solid material and obtain the phase change material.

[0042] Example 2

[0043] A cement-based composite phase change grouting material is made from raw material components comprising the following parts by weight:

[0044] 50 parts silicate cement, 65 parts sand and gravel aggregate, 5.5 parts fiber reinforcement, 2.5 parts polycarboxylate superplasticizer, 10 parts phase change material, 6 parts Class II fly ash, and 45 parts water;

[0045] The preparation method of the cement-based composite phase change grouting material includes the following steps:

[0046] Step 1: Weigh each raw material component separately and prepare them.

[0047] The second step is to add all the raw materials into the mixer, start the mixing, control the mixing speed to 800 r / min, and after mechanical mixing is uniform, discharge the material to obtain cement-based composite phase change grouting material.

[0048] The preparation method of the cement-based composite phase change grouting material includes the following steps:

[0049] Step 1: Weigh each raw material component separately and prepare them.

[0050] The second step is to add all the raw materials into the mixer, turn on the mixer, control the mixing speed to 500 r / min, and after mechanical mixing is uniform, discharge the material to obtain cement-based composite phase change grouting material.

[0051] The method for preparing the fiber-reinforced material includes the following steps:

[0052] Step 1: 1.2g of glass fiber is ultrasonically dispersed in 70% ethanol by volume, followed by the addition of 2.5g of 3-glycidyl etheroxytrimethoxysilane. After the addition is complete, the temperature is raised to 75℃ and kept at that temperature for 6 hours. Then, the material is cooled and discharged to obtain functionalized modified glass fiber.

[0053] Step 2: 1.6g of functionalized modified glass fiber was ultrasonically dispersed in N,N-dimethylformamide medium to form a uniform dispersion. Then, 3g of aspartic acid was added to the dispersion, the temperature was raised to 75℃, and the mixture was stirred for 4 hours. Then, 2.5g of benzidine disulfonic acid and 0.1g of p-toluenesulfonic acid were added to the dispersion. After the addition was complete, the temperature was further raised to 125℃, and the mixture was stirred continuously for 16 hours. Then, the heating was stopped, the material was cooled and discharged, and the solid material was separated and collected to obtain the fiber-reinforced material.

[0054] The method for preparing the phase change material includes the following steps:

[0055] Step S1: Heat 1g of solid paraffin until it is completely melted, add 0.5g of liquid paraffin, stir and mix evenly at 50°C to form paraffin oil, then impregnate 0.1g of expanded vermiculite in the paraffin oil, sonicate at 100kHz for 2 hours, filter, and collect the solid material after no more paraffin is filtered out to form the precursor material.

[0056] Step S2: Disperse 0.5g of precursor material in purified water, then add 1.8g of carboxymethyl starch and 0.2g of sodium trimetaphosphate to the resulting dispersion. After treating at 65°C for 3 hours, cool down and discharge the material to separate the solid material and obtain the phase change material.

[0057] Example 3

[0058] A cement-based composite phase change grouting material is made from raw material components comprising the following parts by weight:

[0059] 55 parts silicate cement, 75 parts sand and gravel aggregate, 6 parts fiber reinforcement, 3 parts polycarboxylate superplasticizer, 15 parts phase change material, 10 parts Class II fly ash, and 50 parts water.

[0060] The preparation method of the cement-based composite phase change grouting material includes the following steps:

[0061] Step 1: Weigh each raw material component separately and prepare them.

[0062] The second step is to add all the raw materials into the mixer, turn on the mixer, control the mixing speed to 1000 r / min, and after mechanical mixing is uniform, discharge the material to obtain cement-based composite phase change grouting material.

[0063] The preparation method of the cement-based composite phase change grouting material includes the following steps:

[0064] Step 1: Weigh each raw material component separately and prepare them.

[0065] The second step is to add all the raw materials into the mixer, turn on the mixer, control the mixing speed to 500 r / min, and after mechanical mixing is uniform, discharge the material to obtain cement-based composite phase change grouting material.

[0066] The method for preparing the fiber-reinforced material includes the following steps:

[0067] Step 1: 1.2g of glass fiber is ultrasonically dispersed in 70% ethanol by volume, followed by the addition of 2.5g of 3-glycidyl etheroxytrimethoxysilane. After the addition is complete, the temperature is raised to 75℃ and kept at that temperature for 6 hours. Then, the material is cooled and discharged to obtain functionalized modified glass fiber.

[0068] Step 2: 1.6g of functionalized modified glass fiber is ultrasonically dispersed in N,N-dimethylformamide medium to form a uniform dispersion. Then, 3g of aspartic acid is added to the dispersion, the temperature is raised to 75℃, and the mixture is stirred for 4 hours. Then, 2.5g of benzidine disulfonic acid and 0.1g of aminosulfonic acid are added to the dispersion. After the addition is complete, the temperature is further raised to 125℃, and the mixture is stirred continuously for 16 hours. Then, the heating is stopped, the material is cooled and discharged, and the solid material is separated and collected to obtain the fiber-reinforced material.

[0069] The method for preparing the phase change material includes the following steps:

[0070] Step S1: Heat 1g of solid paraffin until it is completely melted, add 0.5g of liquid paraffin, stir and mix evenly at 50°C to form paraffin oil, then impregnate 0.1g of expanded vermiculite in the paraffin oil, sonicate at 100kHz for 2 hours, filter, and collect the solid material after no more paraffin is filtered out to form the precursor material.

[0071] Step S2: Disperse 0.5g of precursor material in purified water, then add 1.8g of carboxymethyl starch and 0.2g of sodium trimetaphosphate to the resulting dispersion. After treating at 65°C for 3 hours, cool down and discharge the material to separate the solid material and obtain the phase change material.

[0072] Comparative Example 1

[0073] The "fiber reinforcement" in the raw material components is replaced with "glass fiber", and everything else is the same as in Example 2.

[0074] Comparative Example 2

[0075] The raw material components do not contain "polycarboxylate superplasticizer", and are otherwise the same as in Example 2.

[0076] Comparative Example 3

[0077] Ten parts of "solid paraffin" were added to the raw material components, and the rest was the same as in Example 2.

[0078] Test Example 1

[0079] Mechanical properties were tested in accordance with standard GB / T 17671-1999.

[0080] Crack performance was tested in accordance with standard JGJ / T 70-2009.

[0081] Temperature rise performance test: The grouting materials in Examples 1-3 and Comparative Examples 1-3 were made into 10cm×10cm×2cm test samples, placed in the same outdoor location for direct sunlight, and the temperature on the other side of the sample was tested using a handheld electronic temperature measuring device; the results are shown in Table 1 below.

[0082] Table 1 Results of each performance test

[0083]

[0084] The above embodiments are merely preferred embodiments of the present invention. Any simple modifications, alterations, and substitutions made to the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a cement-based composite phase change grouting material, characterized in that, The cement-based composite phase change grouting material is made from raw material components comprising the following parts by weight: 45-55 parts silicate cement, 60-75 parts sand and gravel aggregate, 4-6 parts fiber reinforcement, 1-3 parts water-reducing agent, 8-15 parts phase change material, 5-10 parts fly ash, and 40-50 parts water. The preparation method includes the following steps: Step 1: Weigh each raw material component separately and prepare them. The second step is to add all the raw materials into the mixer, turn on the mixer, and control the mixing speed to 500 r / min to 1000 r / min. After the mechanical mixing is uniform, the material is discharged to obtain the cement-based composite phase change grouting material. The method for preparing the fiber-reinforced material includes the following steps: Step 1: Use epoxy silane coupling agent as a surface modifier to modify the surface of glass fiber to obtain functionalized modified glass fiber. Step 2: Functionalized modified glass fiber is ultrasonically dispersed in N,N-dimethylformamide medium to form a uniform dispersion. Then, aspartic acid is added to the dispersion, the temperature is raised to 70℃~80℃, and the mixture is stirred for 3h~6h. Then, benzidine disulfonic acid and catalyst are added to the dispersion. After the addition is complete, the temperature is further raised to 120℃~130℃, and the mixture is stirred for 12h~18h. Then, the heating is stopped, the material is cooled and discharged, and the solid material is separated and collected to obtain the fiber-reinforced material. The method for preparing the phase change material includes the following steps: Step S1: After heating the solid paraffin until it is completely melted, add the liquid paraffin and stir and mix it evenly at a temperature of 50℃~55℃ to form paraffin oil. Then, impregnate the expanded vermiculite in the paraffin oil and sonicate it at an ultrasonic frequency of 80kHz~100kHz for 1h~2h. Then filter it until no more paraffin is filtered out and collect the solid material to form the precursor material. Step S2: Disperse the precursor material in purified water, then add carboxymethyl starch and crosslinking agent to the formed dispersion, treat it in a temperature environment of 60℃~70℃ for 2h~4h, cool down and discharge the material, separate the solid material, and the phase change material can be obtained.

2. The preparation method of a cement-based composite phase change grouting material according to claim 1, characterized in that, The epoxy silane coupling agent is selected from one of 3-glycidyl etheroxytrimethoxysilane or 3-glycidyl etheroxytriethoxysilane.

3. The preparation method of a cement-based composite phase change grouting material according to claim 1, characterized in that, The mass ratio of the functionalized modified glass fiber, aspartic acid, and benzidine disulfonic acid is 1:1.5 to 2:1 to 1.

8.

4. The preparation method of a cement-based composite phase change grouting material according to claim 1, characterized in that, The catalyst is selected from either aminosulfonic acid or p-toluenesulfonic acid.

5. The preparation method of a cement-based composite phase change grouting material according to claim 1, characterized in that, The water-reducing agent is selected from either polycarboxylate water-reducing agents or naphthalene-based water-reducing agents.

6. The method for preparing a cement-based composite phase change grouting material according to claim 1, characterized in that, The crosslinking agent is selected from sodium tripolyphosphate or sodium trimetaphosphate.

7. The preparation method of a cement-based composite phase change grouting material according to claim 1, characterized in that, The fly ash is selected from either Grade I fly ash or Grade II fly ash.

8. The application of a cement-based composite phase change grouting material prepared by any one of claims 1 to 7 in the field of building insulation.

Images