Micro-encapsulated phase change composite base polymer concrete, and preparation method and application thereof

Abstract

This invention discloses a microencapsulated phase change composite polymer concrete, its preparation method, and its application. The raw materials include the following parts by weight: 160-165 parts slag, 240-260 parts fly ash, 160-165 parts alkali activator, 56-65 parts water, 160-165 parts dry sand, 860-865 parts coarse aggregate, and 0.1-20 parts microencapsulated phase change material. The microencapsulated phase change composite polymer concrete prepared in this application not only reduces the environmental impact of cement production but also maximizes the heat storage characteristics of the microencapsulated phase change material and improves its compressive strength. It overcomes the technical bottleneck of low mechanical properties in microencapsulated phase change cement-based concrete. Its preparation process is simple and easy to operate, has good application prospects, and can be applied to building materials.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and more specifically, to a microencapsulated phase change composite polymer concrete, its preparation method, and its application. Background Technology

[0002] Microencapsulated phase change materials absorb excess heat during the day by melting, and release this heat and solidify at night when temperatures drop. They possess a high latent heat capacity, allowing them to store significant amounts of heat energy during the phase change process, attracting attention in the construction industry due to their excellent heat storage capabilities. However, the addition of microencapsulated phase change materials increases the interfacial gap between them and the concrete matrix, leading to a substantial decrease in the compressive strength of cement-based concrete, greatly limiting the development and application of microencapsulated phase change materials. Furthermore, cement production generates large amounts of CO2 greenhouse gases, causing severe environmental pollution.

[0003] Existing technologies utilize industrial wastes such as fly ash and slag, combined with alkali activators to prepare geopolymers, which can serve as a substitute for ordinary silicate cement, reducing environmental pollution during cement production and representing a novel green inorganic cementitious material. During hydration, geopolymers form high-strength C / NASH gels, possessing excellent mechanical strength and improving interfacial bond strength between concrete matrices, making them a high-performance building material. However, while composite geopolymers exhibit excellent strength, their synergistic effect with microencapsulated phase change materials (PCMs) remains unclear, and substantial research data and theoretical support are scarce. In particular, research on the impact of PCM substitution rates on the mechanical properties of composite geopolymer concrete is limited, significantly hindering its widespread adoption and application. Therefore, perfectly combining the advantages of microencapsulated PCMs with geopolymer concrete is crucial for promoting this new building material. Moreover, how to effectively utilize and dispose of large amounts of construction waste is an increasingly important issue. With the rapid development of the construction industry, the amount of concrete used is gradually increasing. Processing waste concrete into recycled aggregates after crushing and grading can reduce environmental pollution caused by construction waste and also meet some of the construction industry's demand for sand and gravel. However, there are also problems such as rough material surface, high porosity, and susceptibility to cracking due to external forces. Therefore, improving the mechanical properties of coarse aggregates is also an urgent problem to be solved. Summary of the Invention

[0004] Based on this, in order to address the insufficient research on the impact of microencapsulated phase change material substitution rate on the mechanical properties of composite matrix polymers in existing technologies, as well as the problems of material surface roughness, high porosity, and susceptibility to cracking under external forces, this invention provides a microencapsulated phase change composite matrix polymer concrete, its preparation method, and its application. The specific technical solution is as follows:

[0005] A microencapsulated phase change composite polymer concrete, comprising the following raw materials by weight: 160-165 parts slag, 240-260 parts fly ash, 160-165 parts alkali activator, 56-65 parts water, 160-165 parts dry sand, 860-865 parts coarse aggregate, and 0.1-20 parts microencapsulated phase change material;

[0006] The alkaline activator is obtained by mixing sodium hydroxide and sodium silicate in a volume ratio of (0.4-0.6):1;

[0007] The structure of the microencapsulated phase change material includes a shell and a core material, wherein the shell encapsulates the core material, the shell is a copolymer of low-density polyethylene and vinyl acetate, and the core material is paraffin wax.

[0008] Furthermore, the melting point of the microencapsulated phase change material is 28.4±0.9℃.

[0009] Furthermore, the preparation method of the micro-encapsulated phase change material includes the following steps:

[0010] Low-density polyethylene and vinyl acetate are added to a reaction vessel, heated to 100℃~200℃, and treated at 100℃~200℃ for 1h~5h. Then paraffin is added and spray-dried to obtain microencapsulated phase change material.

[0011] Furthermore, the mass ratio of the low-density polyethylene to the vinyl acetate is (1-5):(1-3).

[0012] Furthermore, the amount of paraffin added accounts for 35% to 75% of the mass of the microencapsulated phase change material.

[0013] Furthermore, the spray drying temperature is 120℃~180℃.

[0014] Furthermore, the coarse aggregate is construction waste, obtained through crushing, grading, and modification.

[0015] Further, the modification treatment is as follows: the graded coarse aggregate is soaked in methyl methacrylate and heated to 40℃~45℃, then aluminum acetylacetonate is added and soaked for 12h~15h to obtain soaked coarse aggregate; the soaked coarse aggregate is placed in water at a temperature of 50℃~80℃ for 5h~8h and then dried.

[0016] In addition, this application also provides a method for preparing microencapsulated phase change composite polymer concrete, the preparation method comprising the following steps:

[0017] Fly ash, slag, alkali activator and water are mixed to obtain a composite matrix polymer slurry;

[0018] The composite base polymer slurry is added to dry sand and stirred thoroughly for 30s to 60s to obtain composite base polymer mortar.

[0019] Add coarse aggregate to the composite polymer mortar and stir thoroughly for 2 to 5 minutes to obtain composite polymer concrete.

[0020] The microencapsulated phase change composite matrix polymer concrete is stirred thoroughly for 2 to 5 minutes to obtain the microencapsulated phase change composite matrix polymer concrete.

[0021] This application also provides an application of microencapsulated phase change composite matrix polymer concrete, wherein the microencapsulated phase change composite matrix polymer concrete is used as a building material, and the building material is used as a semi-finished material and / or a finished material.

[0022] Compared with existing technologies, its beneficial effects include: the raw material for the coarse aggregate in this application is waste building materials, which not only realizes waste reuse, but also, after modification, yields reusable coarse aggregate that is less prone to cracking, less brittle, and has significantly improved mechanical properties. When applied to the micro-encapsulated phase change composite polymer concrete of this application, it significantly improves the mechanical properties of the micro-encapsulated phase change composite polymer concrete. Furthermore, the micro-encapsulated phase change composite polymer concrete prepared in this application not only reduces the environmental impact of cement production but also maximizes the heat storage characteristics of the micro-encapsulated phase change material and improves the compressive strength of the micro-encapsulated phase change composite polymer concrete. It overcomes the technical bottleneck of low mechanical properties in micro-encapsulated phase change cement-based concrete. Its preparation process is simple and easy to operate, has good application prospects, and can be applied to building materials. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to its embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of protection of the invention.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] In one embodiment of this application, a microencapsulated phase change composite polymer concrete comprises, by weight, the following raw materials: 160-165 parts slag, 240-260 parts fly ash, 160-165 parts alkali activator, 56-65 parts water, 160-165 parts dry sand, 860-865 parts coarse aggregate, and 0.1-20 parts microencapsulated phase change material.

[0026] The alkaline activator is obtained by mixing sodium hydroxide and sodium silicate in a volume ratio of (0.4-0.6):1;

[0027] The structure of the microencapsulated phase change material includes a shell and a core material, wherein the shell encapsulates the core material, the shell is a copolymer of low-density polyethylene and vinyl acetate, and the core material is paraffin wax.

[0028] In one embodiment, the fly ash is grade F low-calcium fly ash, and the slag has a CaO content of 43.97%.

[0029] In one embodiment, the molar concentration of the sodium hydroxide is 14 mol / L.

[0030] In one embodiment, the melting point of the microencapsulated phase change material is 28.4 ± 0.9 °C.

[0031] In one embodiment, the method for preparing the microencapsulated phase change material includes the following steps:

[0032] Low-density polyethylene and vinyl acetate are added to a reaction vessel, heated to 100℃~200℃, and treated at 100℃~200℃ for 1h~5h. Then paraffin is added and spray-dried to obtain microencapsulated phase change material.

[0033] In one embodiment, the mass ratio of the low-density polyethylene to the vinyl acetate is (1-5):(1-3).

[0034] In one embodiment, the total mass of the low-density polyethylene and the vinyl acetate accounts for 25% to 65% of the mass of the microencapsulated phase change material.

[0035] In one embodiment, the amount of paraffin added is 35% to 75% of the mass of the microencapsulated phase change material.

[0036] In one embodiment, the spray drying temperature is 120°C to 180°C.

[0037] In one embodiment, the coarse aggregate is construction waste, obtained through crushing, grading, and modification.

[0038] In one embodiment, the modification process is as follows: the graded coarse aggregate is soaked in methyl methacrylate and heated to 40°C to 45°C, then aluminum acetylacetonate is added and soaked for 12 to 15 hours to obtain soaked coarse aggregate; the soaked coarse aggregate is placed in water at a temperature of 50°C to 80°C for 5 to 8 hours and then dried.

[0039] In one embodiment, the amount of aluminum acetylacetonate added is 0.1% to 3% of the mass of methyl methacrylate.

[0040] In addition, this application also provides a method for preparing microencapsulated phase change composite polymer concrete, the preparation method comprising the following steps:

[0041] Fly ash, slag, alkali activator and water are mixed to obtain a composite matrix polymer slurry;

[0042] The composite base polymer slurry is added to dry sand and stirred thoroughly for 30s to 60s to obtain composite base polymer mortar.

[0043] Add coarse aggregate to the composite polymer mortar and stir thoroughly for 2 to 5 minutes to obtain composite polymer concrete.

[0044] The microencapsulated phase change composite matrix polymer concrete is stirred thoroughly for 2 to 5 minutes to obtain the microencapsulated phase change composite matrix polymer concrete.

[0045] This application also provides an application of microencapsulated phase change composite matrix polymer concrete, wherein the microencapsulated phase change composite matrix polymer concrete is used as a building material, and the building material is used as a semi-finished material and / or a finished material.

[0046] The implementation schemes of the present invention will now be described in detail with reference to specific embodiments.

[0047] Example 1:

[0048] A method for preparing microencapsulated phase change composite polymer concrete, the method comprising the following steps:

[0049] Low-density polyethylene and vinyl acetate in a mass ratio of 3:1 were added to a reaction vessel, heated to 150°C, and treated at 150°C for 5 hours. Then, paraffin wax was added, and the mixture was spray-dried at 180°C. The total mass of the low-density polyethylene and vinyl acetate accounted for 25% of the mass of the microencapsulated phase change material, and the amount of paraffin wax added accounted for 75% of the mass of the microencapsulated phase change material, thus obtaining the microencapsulated phase change material.

[0050] Construction waste is crushed and graded. The graded coarse aggregate is then soaked in methyl methacrylate and heated to 45°C. Then, 3% aluminum acetylacetonate (based on the mass of methyl methacrylate) is added and the mixture is soaked for 15 hours to obtain soaked coarse aggregate. The soaked coarse aggregate is then placed in water at 50°C for 5 hours and dried to obtain coarse aggregate.

[0051] 243 parts fly ash, 162 parts slag, 162 parts alkali activator (the alkali activator is obtained by mixing sodium hydroxide and sodium silicate in a volume ratio of 0.5:1) and 57 parts water to obtain a composite macropolymer slurry;

[0052] The composite base polymer slurry was added to 162 parts of dry sand and stirred thoroughly for 30 seconds to obtain the composite base polymer mortar.

[0053] Add 863 parts of coarse aggregate to the composite geopolymer mortar and stir thoroughly for 2 minutes to obtain composite geopolymer concrete.

[0054] Twelve portions of the microencapsulated phase change material were added to the composite matrix polymer concrete and stirred thoroughly for 2 minutes to obtain the microencapsulated phase change composite matrix polymer concrete.

[0055] Example 2:

[0056] A method for preparing microencapsulated phase change composite polymer concrete, the method comprising the following steps:

[0057] Low-density polyethylene and vinyl acetate in a mass ratio of 3:3 were added to a reaction vessel, heated to 150°C, and treated at 150°C for 5 hours. Then, paraffin wax was added, and the mixture was spray-dried at 180°C. The total mass of the low-density polyethylene and vinyl acetate accounted for 25% of the mass of the microencapsulated phase change material, and the amount of paraffin wax added accounted for 75% of the mass of the microencapsulated phase change material, thus obtaining the microencapsulated phase change material.

[0058] Construction waste is crushed and graded. The graded coarse aggregate is then soaked in methyl methacrylate and heated to 45°C. Then, 3% aluminum acetylacetonate (based on the mass of methyl methacrylate) is added and the mixture is soaked for 15 hours to obtain soaked coarse aggregate. The soaked coarse aggregate is then placed in water at 50°C for 5 hours and dried to obtain coarse aggregate.

[0059] 243.2 parts of fly ash, 163.1 parts of slag, 162.3 parts of alkali activator (the alkali activator is obtained by mixing sodium hydroxide and sodium silicate in a volume ratio of 0.4:1) and 57.5 parts of water to obtain a composite macropolymer slurry;

[0060] The composite base polymer slurry was added to 163.4 parts of dry sand and stirred thoroughly for 30 seconds to obtain composite base polymer mortar.

[0061] Add 868.9 parts of coarse aggregate to the composite geopolymer mortar and stir thoroughly for 2 minutes to obtain composite geopolymer concrete;

[0062] Twelve portions of the microencapsulated phase change material were added to the composite matrix polymer concrete and stirred thoroughly for 2 minutes to obtain the microencapsulated phase change composite matrix polymer concrete.

[0063] Example 3:

[0064] A method for preparing microencapsulated phase change composite polymer concrete, the method comprising the following steps:

[0065] Low-density polyethylene and vinyl acetate in a mass ratio of 5:3 were added to a reaction vessel, heated to 150°C, and treated at 150°C for 5 hours. Then, paraffin wax was added, and the mixture was spray-dried at 180°C. The total mass of the low-density polyethylene and vinyl acetate accounted for 25% of the mass of the microencapsulated phase change material, and the amount of paraffin wax added accounted for 75% of the mass of the microencapsulated phase change material, thus obtaining the microencapsulated phase change material.

[0066] Construction waste is crushed and graded. The graded coarse aggregate is then soaked in methyl methacrylate and heated to 45°C. Then, 3% aluminum acetylacetonate (based on the mass of methyl methacrylate) is added and the mixture is soaked for 15 hours to obtain soaked coarse aggregate. The soaked coarse aggregate is then placed in water at 50°C for 5 hours and dried to obtain coarse aggregate.

[0067] 242.6 parts of fly ash, 161.4 parts of slag, 161.6 parts of alkali activator (the alkali activator is obtained by mixing sodium hydroxide and sodium silicate in a volume ratio of 0.4:1) and 56.4 parts of water to obtain a composite macropolymer slurry;

[0068] The composite base polymer slurry was added to 161.4 parts of dry sand and stirred thoroughly for 30 seconds to obtain composite base polymer mortar.

[0069] Add 868.6 parts of coarse aggregate to the composite geopolymer mortar and stir thoroughly for 2 minutes to obtain composite geopolymer concrete;

[0070] Twelve portions of the microencapsulated phase change material were added to the composite matrix polymer concrete and stirred thoroughly for 2 minutes to obtain the microencapsulated phase change composite matrix polymer concrete.

[0071] Comparative Example 1:

[0072] The difference between Comparative Example 1 and Example 3 is that no micro-encapsulated phase change material was added in Comparative Example 1, while the rest is the same as in Example 3.

[0073] Comparative Example 2:

[0074] The difference between Comparative Example 2 and Example 3 is that the outer shell material of the micro-encapsulated phase change material added in Comparative Example 2 is high-density polyethylene, and the core material is paraffin wax. Everything else is the same as in Example 3.

[0075] Comparative Example 3:

[0076] The difference between Comparative Example 3 and Example 3 is that 60 parts of microencapsulated phase change material were added to Comparative Example 3, while the rest were the same as in Example 3.

[0077] Comparative Example 4:

[0078] The difference between Comparative Example 4 and Example 3 is that the alkaline activator in Comparative Example 4 is sodium lactate alone, while the rest is the same as in Example 3.

[0079] Comparative Example 5:

[0080] The difference between Comparative Example 5 and Example 3 is that the coarse aggregate in Comparative Example 5 was not modified, while the rest was the same as in Example 3.

[0081] Comparative Example 6:

[0082] The difference between Comparative Example 6 and Example 3 is that aluminum acetylacetonate was not added during the coarse aggregate modification process in Comparative Example 6, while the rest was the same as in Example 3.

[0083] The samples from Examples 1-3 and Comparative Examples 1-6 were subjected to performance tests. The Abram cone was used as the mold according to the British Standard BSEN 12350-2-2009, Standard for Testing Fresh Concrete. The cone was 300 mm high, with a top diameter of 100 mm and a bottom diameter of 200 mm. The workability of the products prepared in Examples 1 and Comparative Examples 1-3 was tested according to the British Standard BSEN 12390-3-2017, Standard for Testing Hardened Concrete, using a pressure of 0.8 kN / s. The test results are shown in Table 1 below.

[0084] Table 1: Performance Test Results

[0085]

[0086] Analysis of the data in Table 1 shows that the amount of micro-encapsulated phase change material added has a significant impact on the slump and compressive strength of the prepared micro-encapsulated phase change composite polymer concrete. This application controls the amount of micro-encapsulated phase change material added to ensure that the slump and compressive strength are within a suitable range for use, resulting in micro-encapsulated phase change composite polymer concrete with good workability and mechanical properties. It leverages both the heat storage performance of the micro-encapsulated phase change material and the high strength of the composite polymer concrete, making it a novel green building material. Furthermore, the modification treatment of coarse aggregate in this application helps improve the micro-cracks and porosity of the coarse aggregate, increasing its density and also contributing to the improvement of the mechanical properties of the micro-encapsulated phase change composite polymer concrete.

[0087] The above embodiments should be understood as illustrative only and not as limiting the scope of protection of the present invention. After reading the description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent changes and modifications also fall within the scope defined by the claims of the present invention.

Claims

1. A microencapsulated phase change composite polymer concrete, characterized in that, By weight, the following raw materials are included: 160-165 parts slag, 240-260 parts fly ash, 160-165 parts alkali activator, 56-65 parts water, 160-165 parts dry sand, 860-865 parts coarse aggregate, and 0.1-20 parts micro-encapsulated phase change material. The alkaline activator is obtained by mixing sodium hydroxide and sodium silicate in a volume ratio of (0.4~0.6):1; The structure of the microencapsulated phase change material includes an outer shell and a core material, wherein the outer shell encapsulates the core material. The outer shell is a copolymer of low-density polyethylene and vinyl acetate, and the core material is paraffin wax. The melting point of the microencapsulated phase change material is 28.4 ± 0.9℃. The coarse aggregate is construction waste, which is obtained through crushing, grading and modification. The modification process is as follows: the graded coarse aggregate is soaked in methyl methacrylate and heated to 40℃~45℃, then aluminum acetylacetonate is added and soaked for 12h~15h to obtain soaked coarse aggregate; the soaked coarse aggregate is placed in water at 50℃~80℃ for 5h~8h and then dried.

2. The microencapsulated phase change composite polymer concrete according to claim 1, characterized in that, The preparation method of the micro-encapsulated phase change material includes the following steps: Low-density polyethylene and vinyl acetate are added to a reaction vessel, heated to 100℃~200℃, and treated at 100℃~200℃ for 1h~5h. Then paraffin is added and spray-dried to obtain microencapsulated phase change material.

3. The microencapsulated phase change composite polymer concrete according to claim 1, characterized in that, The mass ratio of the low-density polyethylene to the vinyl acetate is (1~5):(1~3).

4. The microencapsulated phase change composite polymer concrete according to claim 3, characterized in that, The amount of paraffin added accounts for 35% to 75% of the mass of the microencapsulated phase change material.

5. The microencapsulated phase change composite polymer concrete according to claim 2, characterized in that, The spray drying temperature is 120℃~180℃.

6. A method for preparing microencapsulated phase change composite polymer concrete, characterized in that, The preparation method is used to prepare the microencapsulated phase change composite macropolymer concrete as described in any one of claims 1 to 5, and the preparation method includes the following steps: Fly ash, slag, alkali activator and water are mixed to obtain a composite matrix polymer slurry; The composite base polymer slurry is added to dry sand and stirred thoroughly for 30 to 60 seconds to obtain composite base polymer mortar. Add coarse aggregate to the composite macropolymer mortar and stir thoroughly for 2 to 5 minutes to obtain composite macropolymer concrete. The microencapsulated phase change composite matrix polymer concrete is stirred thoroughly for 2 to 5 minutes to obtain the microencapsulated phase change composite matrix polymer concrete.

7. An application of a microencapsulated phase change composite polymer concrete, characterized in that, The application is the use of the microencapsulated phase change composite polymer concrete as described in claim 1 as a building material, wherein the building material is used as a semi-finished material and / or a finished material.

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