Microcapsule sustained-release material, preparation method and application thereof

Abstract

The present application relates to the field of concrete temperature control and crack prevention, and particularly relates to a microcapsule slow-release material, a preparation method and application thereof. The microcapsule slow-release material comprises a core and a coating layer. The core comprises a porous carbon material and a temperature suppression material, and the coating layer is a hot melt adhesive film. The microcapsule slow-release material can achieve three-stage slow-release of heat release, porous structure slow-release and temperature suppression material dissolution slow-release, and has a persistent and excellent temperature suppression effect. In the early stage, the temperature suppression material is not consumed, and the setting and demolding of the concrete are basically not affected. In the later stage, the temperature suppression material is continuously released, the maximum temperature of the concrete is reduced, and the risk of temperature shrinkage cracking of the concrete is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of concrete temperature control and crack prevention, and particularly relates to a microcapsule sustained-release material and a preparation method and application thereof. BACKGROUND

[0002] In the hydration process, the cementitious material releases a large amount of hydration heat, which causes the temperature of the concrete to rise. In the process of temperature reduction, the structure in a constrained state is prone to temperature shrinkage cracking. In recent years, medium-sized structures such as tunnel lining, subway pipe gallery side wall, and civil engineering basement outer wall use high-strength grade concrete. Due to the influence of factors such as large amount of cement, cement superfine, and high C3S content, the phenomenon of temperature shrinkage cracking is increasing. However, the existing materials for temperature control and crack prevention of medium-sized concrete structures have the defect of poor temperature inhibition effect, and the effect of inhibiting temperature shrinkage cracking of concrete is poor. SUMMARY

[0003] Therefore, the technical problem to be solved by the present application is to overcome the defect of poor temperature inhibition effect of the temperature control and crack prevention material in the prior art, so as to provide a microcapsule sustained-release material and a preparation method and application thereof.

[0004] To this end, the present application provides the following technical solutions:

[0005] The present application provides a microcapsule sustained-release material, which comprises a core and a coating layer; the core comprises a porous carbon material and a temperature inhibition material, and the coating layer is a hot melt adhesive film.

[0006] In an optional embodiment, the mass ratio of the temperature inhibition material, the porous carbon material, and the hot melt adhesive film is (55-80):(40-50):(3-5).

[0007] Optionally, the particle size of the microcapsule sustained-release material is 0.05-0.6mm.

[0008] Optionally, the microcapsule sustained-release material is divided into first, second, and third microcapsule sustained-release materials according to particle size; the particle size a of the first microcapsule sustained-release material is 0.05mm≤a<0.1mm; the particle size b of the second microcapsule sustained-release material is 0.1mm≤b<0.3mm; and the particle size c of the third microcapsule sustained-release material is 0.3mm≤c≤0.6mm.

[0009] Optionally, the mass ratio of the first, second, and third microcapsule sustained-release materials is (0.5-1.5):(0.5-1.5):(0.5-1.5).

[0010] The present application further strengthens the slow-release effect (small particle size is preferentially released, and large particle size is slowly released) by setting a specific particle size grading and matching microcapsule slow-release materials with different particle sizes.

[0011] The particle size of the microcapsule slow-release material in the present application can be controlled by conventional technical means in the art, which can be obtained by adjusting the granulation process during preparation or screening and combining after preparation to obtain the specific particle size grading of the microcapsule slow-release material.

[0012] In an alternative embodiment, the temperature suppression material comprises modified starch.

[0013] Optionally, the modification method of the starch in the modified starch comprises one or more of physical modification, chemical modification and enzymatic modification; the methods of physical modification, chemical modification and enzymatic modification can be used by conventional methods in the art.

[0014] Optionally, the modified starch comprises one or more of hydroxypropyl distarch phosphate, sodium octenyl succinate starch and yellow dextrin.

[0015] Optionally, the modified starch comprises hydroxypropyl distarch phosphate, sodium octenyl succinate starch and yellow dextrin.

[0016] Optionally, the mass ratio of the hydroxypropyl distarch phosphate, the sodium octenyl succinate starch and the yellow dextrin is (10-20):(15-20):(30-40).

[0017] In an alternative embodiment, the porous carbon material comprises one or more of activated carbon, carbon nanotubes, carbon aerogel and biochar.

[0018] Optionally, the biochar comprises sludge-derived carbon material.

[0019] Optionally, the preparation method of the sludge-derived carbon material comprises the following steps: sintering the sludge under a protective atmosphere to obtain the sludge-derived carbon material.

[0020] Optionally, the protective atmosphere comprises nitrogen or inert atmosphere; the inert atmosphere comprises argon or helium.

[0021] Optionally, the sintering temperature is 800-1000℃, and the time is 1-2h.

[0022] In an alternative embodiment, the melting point of the hot melt adhesive film is 50-65℃.

[0023] Optionally, the hot melt adhesive film is a TPU (thermoplastic polyurethane elastomer) hot melt adhesive film.

[0024] In another aspect, the present application provides a preparation method of the microcapsule sustained-release material, comprising the following steps:

[0025] Mixing the temperature-reducing material, the porous carbon material and water, and granulating to obtain granules;

[0026] Mixing the granules with the hot melt adhesive film in a molten state to obtain the microcapsule sustained-release material.

[0027] In an alternative embodiment, the step of mixing the temperature-reducing material, the porous carbon material and water, and granulating to obtain granules comprises:

[0028] Mixing the temperature-reducing material and water to obtain a first mixture;

[0029] After heating the first mixture to a target temperature, mixing the porous carbon material to obtain a second mixture, and then granulating to obtain granules.

[0030] Optionally, the mass solid content of the first mixture is 25-35%.

[0031] Optionally, the target temperature is 50-60℃.

[0032] In an alternative embodiment, the porous carbon material further comprises an acid washing process before use, and the purpose of the acid washing is to obtain more pores.

[0033] Optionally, the acid washing reagent comprises a sulfuric acid solution, and the concentration of the sulfuric acid solution is 0.8-1.2 mol / L.

[0034] The present application does not specially limit the amount of the acid washing reagent, as long as it can completely immerse the porous carbon material.

[0035] Optionally, the acid washing temperature is 20-30℃, and the acid washing time is 22-26h.

[0036] Optionally, the granulation method is centrifugal spray granulation.

[0037] Optionally, after granulation, cooling is performed to obtain the granules.

[0038] Optionally, the cooling method is natural cooling or air cooling, and the target temperature of the cooling is ≤30℃.

[0039] Optionally, the air cooling is performed by introducing room temperature air into the granules, and the present application does not specially limit the introduction rate of the room temperature air, as long as it can cool to the target temperature.

[0040] In an alternative embodiment, the hot melt adhesive film in a molten state is obtained by preheating the hot melt adhesive film.

[0041] Optionally, the preheating temperature is 90-110℃.

[0042] Optionally, the rotating speed of mixing the granules with the hot melt adhesive film in the molten state is 250-350 r / min; and the mixing is performed until a homogeneous mixture is formed.

[0043] Optionally, the mixing time is 5-10 min.

[0044] In an optional embodiment, the granules are mixed with the hot melt adhesive film to prepare the microcapsule sustained-release material by mechanical friction film sealing.

[0045] The application further provides an application of the microcapsule sustained-release material or the microcapsule sustained-release material prepared by the preparation method in controlling temperature shrinkage cracking of concrete.

[0046] In an optional embodiment, the concrete includes concrete for tunnel lining, concrete for side wall of subway pipe gallery, or concrete for outer wall of basement of civil construction.

[0047] The technical scheme of the application has the following advantages:

[0048] 1. The application provides a microcapsule sustained-release material, which comprises a core and a coating layer; the core comprises porous carbon material and temperature control material, and the coating layer is a hot melt adhesive film.

[0049] The microcapsule sustained-release material can realize three-stage sustained release of heat release, porous structure sustained release, and temperature control material dissolution sustained release, and has a long-lasting and excellent temperature control effect. Specifically, after the microcapsule sustained-release material is mixed into concrete, it is not directly released at this time, which does not affect the cement hydration process; as the cement hydration temperature rises, when the temperature rises to 40-50℃, the outermost hot melt adhesive film melts first, opening the surface pores of the porous carbon material, and the temperature control material (modified starch) near the surface rapidly wraps around the surface of the cement particles to form a complex, inhibiting the cement hydration, which is the first release; the cement continues to hydrate and breaks through the complex coating, at this time, the temperature control material in the interior of the porous carbon material will be released from the interior successively due to the concentration difference, continuing to inhibit the hydration, which is the second release; at the same time, the temperature control material itself has a solubility that increases with the temperature rise, forming the third release; thus, a three-stage sustained release structure is formed, and the higher the temperature, the more the release, and the more the inhibition, so that the temperature control material is not consumed at an early low temperature, basically not affecting the concrete setting and demolding, and the temperature control material is continuously released at a later high temperature stage, reducing the maximum temperature of the concrete and reducing the risk of temperature shrinkage cracking of the concrete.

[0050] 2.The temperature control material comprises modified starch, and the modified starch comprises hydroxypropyl distarch phosphate, sodium octenyl succinate starch and yellow dextrin, and the mass ratio of the hydroxypropyl distarch phosphate, the sodium octenyl succinate starch and the yellow dextrin is (10-20) :(15-20) :(30-40). The hydroxypropyl distarch phosphate is a modified starch crosslinked by phosphate, and the phosphate has a good temperature control effect on cement hydration. The hydroxypropyl distarch phosphate modified by phosphate crosslinking and hydroxypropyl etherization has a better temperature control effect than conventional modified starch. The sodium octenyl succinate starch has the characteristics of hydrophobicity, lipophilicity and solubility after heating, and can achieve slow release during hydration temperature rise. The yellow dextrin has a small amount and a fast dissolution speed compared with the other two, and the three can be combined in different mass ratios to form a slow-release combination with different dissolution rates.

[0051] 3.The porous carbon material comprises one or more of activated carbon, carbon nanotube, carbon aerogel and biochar, and the biochar comprises sludge-derived carbon material. The biochar has the advantages of wide source, renewability and environmental protection, and the sludge-derived carbon material can realize adjustable pore size during preparation, which is beneficial to the preparation of the microcapsule slow-release material.

[0052] 4.The hot melt adhesive film is a TPU hot melt adhesive film, and the TPU hot melt adhesive film has excellent mechanical properties and durability, and has the characteristics of viscosity after heating and fast drying after cooling, and is suitable for preparing the microcapsule slow-release material.

[0053] 5.The application provides a preparation method of the microcapsule slow-release material, comprising the following steps: mixing the temperature control material, the porous carbon material and water, and granulating to obtain granules; and mixing the granules with the hot melt adhesive film in a molten state to obtain the microcapsule slow-release material. The application adopts a twice encapsulation process, once encapsulation: the porous carbon material encapsulates the temperature control material by mixing and granulating; and twice encapsulation: the hot melt adhesive film is encapsulated by high-speed stirring mechanical friction.

[0054] 6.The application sets the particle size of the final microcapsule slow-release material to 0.05-0.6mm, and the microcapsule slow-release material has the best slow-release effect and temperature control effect in this particle size range. BRIEF DESCRIPTION OF DRAWINGS

[0055] In order to more clearly illustrate the specific embodiments of the application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. Obviously, the drawings described below are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0056] Figure 1is a schematic diagram of temperature rising of single cement, first mixed material and second mixed material in the present application;

[0057] Figure 2 is a schematic diagram of temperature rising of single cement, third mixed material in the present application;

[0058] Figure 3 is a schematic diagram of temperature rising of single cement, fourth mixed material in the present application;

[0059] Figure 4 is a schematic diagram of temperature rising of single cement, fifth mixed material and sixth mixed material in the present application;

[0060] Figure 5 is a temperature and stress curve of two concrete test pieces in the present application. DETAILED DESCRIPTION

[0061] The following examples are provided to better further understand the present application, and are not limited to the best mode, and do not constitute a limitation on the content and protection scope of the present application, and any person under the inspiration of the present application or the combination of the present application with other prior art features, any product same or similar to the present application, falls within the protection scope of the present application.

[0062] The specific experimental steps or conditions are not indicated in the examples, and can be operated according to the conventional experimental steps described in the literature in the art or the operation or conditions. The reagents or instruments used are not indicated by the manufacturer, and are conventional reagent products that can be obtained by market purchase.

[0063] In the examples of the present application, hydroxypropyl distarch phosphate is purchased from Hangzhou Prostar Starch Co., Ltd., and the model number is HP-CF W0390;

[0064] Sodium octenyl succinate starch is purchased from Hangzhou Ruilin Chemical Co., Ltd., and the model number is SS0S-A;

[0065] Yellow dextrin is purchased from Shandong Chengshun Chemical Technology Co., Ltd.;

[0066] The sludge is derived from Zhuhai Weili Gao Biological Technology Co., Ltd.;

[0067] TPU hot melt adhesive film is purchased from Dongguan Meidinlian New Material Co., Ltd., and the melting point is 50-65℃.

[0068] Example 1

[0069] The present embodiment provides a preparation method of a microcapsule slow-release material, comprising the following steps:

[0070] The sludge is sintered at 900 DEG C for 1.5 h under a nitrogen atmosphere to obtain a sludge-derived carbon material; the sludge-derived carbon material is immersed in a 1 mol / L sulfuric acid solution, and the temperature of the immersion is set to 25 DEG C and the time is set to 24 h to obtain an acid-washed sludge-derived carbon material;

[0071] 10 g of hydroxypropyl distarch phosphate, 20 g of sodium octenyl succinate starch, 30 g of yellow dextrin, and water are mixed to obtain a first mixed solution with a mass solid content of 30%; the first mixed solution is heated to 50 DEG C and mixed with 40 g of the acid-washed sludge-derived carbon material to obtain a second mixed solution, and then centrifugal spray granulation is performed; after the granulation is completed, the granulation is naturally cooled to 25 DEG C to obtain granules; 5 g of the TPU hot melt adhesive film preheated to 100 DEG C is added to the granules under high-speed stirring, the stirring speed is 300 r / min, and the stirring time is 10 min; and the microcapsule slow-release material is prepared by mechanical friction film sealing.

[0072] The particle size of the microcapsule slow-release material is 0.05-0.6 mm (the particle size a of the first microcapsule slow-release material is 0.05 mm≤a<0.1 mm; the particle size b of the second microcapsule slow-release material is 0.1 mm≤b<0.3 mm; the particle size c of the third microcapsule slow-release material is 0.3 mm≤c≤0.6 mm; and the mass ratio of the first microcapsule slow-release material, the second microcapsule slow-release material, and the third microcapsule slow-release material is 1:1:1).

[0073] Example 2

[0074] The present embodiment provides a preparation method of a microcapsule slow-release material, which comprises the following steps:

[0075] The acid-washed sludge-derived carbon material is prepared by the same method as in Example 1;

[0076] 20 g of hydroxypropyl distarch phosphate, 15 g of sodium octenyl succinate starch, 40 g of yellow dextrin, and water are mixed to obtain a first mixed solution with a mass solid content of 28%; the first mixed solution is heated to 55 DEG C and mixed with 45 g of the acid-washed sludge-derived carbon material to obtain a second mixed solution, and then centrifugal spray granulation is performed; after the granulation is completed, the granulation is naturally cooled to 25 DEG C to obtain granules; 4 g of the TPU hot melt adhesive film preheated to 95 DEG C is added to the granules under high-speed stirring, the stirring speed is 280 r / min, and the stirring time is 8 min; and the microcapsule slow-release material is prepared by mechanical friction film sealing.

[0077] The particle size of the microcapsule slow-release material is 0.05-0.6 mm (the particle size a of the first microcapsule slow-release material is 0.05 mm≤a<0.1 mm; the particle size b of the second microcapsule slow-release material is 0.1 mm≤b<0.3 mm; the particle size c of the third microcapsule slow-release material is 0.3 mm≤c≤0.6 mm; and the mass ratio of the first microcapsule slow-release material, the second microcapsule slow-release material and the third microcapsule slow-release material is 0.5:0.5:1).

[0078] Example 3

[0079] The present embodiment provides a preparation method of a microcapsule slow-release material, comprising the following steps:

[0080] The acid-washed sludge-derived carbon material is prepared by the same method as in Example 1.

[0081] 20 g of hydroxypropyl distarch phosphate, 20 g of octenyl succinate sodium starch, 30 g of yellow dextrin and water are mixed to obtain a first mixed solution with a mass solid content of 33%; the first mixed solution is heated to 58°C and mixed with 50 g of the acid-washed sludge-derived carbon material to obtain a second mixed solution, and then centrifugal spray granulation is performed, and after the granulation is completed, the granules are naturally cooled to 25°C; 3 g of the preheated TPU hot melt adhesive film is added to the high-speed stirred granules, the stirring speed is 350 r / min, and the stirring time is 6 min, and the microcapsule slow-release material is prepared by mechanical friction film sealing.

[0082] The particle size of the microcapsule slow-release material is 0.05-0.6 mm (the particle size a of the first microcapsule slow-release material is 0.05 mm≤a<0.1 mm; the particle size b of the second microcapsule slow-release material is 0.1 mm≤b<0.3 mm; the particle size c of the third microcapsule slow-release material is 0.3 mm≤c≤0.6 mm; and the mass ratio of the first microcapsule slow-release material, the second microcapsule slow-release material and the third microcapsule slow-release material is 0.8:1.2:1).

[0083] Comparative Example 1

[0084] The commercially available ordinary cement hydration inhibitor is purchased from Tianjin Paoming Co., Ltd., and the model is BM-Y type.

[0085] Comparative Example 2

[0086] The present comparative example provides a preparation method of a temperature suppression material, comprising the following steps:

[0087] 10 g of hydroxypropyl distarch phosphate, 20 g of octenyl succinate sodium starch and 30 g of yellow dextrin are mixed to obtain the temperature suppression material.

[0088] Test Example 1

[0089] (1) The cement is mixed with the microcapsule sustained-release material prepared in Example 1 to obtain a first mixed material (the content of the microcapsule sustained-release material in the first mixed material is 0.2 wt%). The cement used is benchmark cement (P·I 425, production batch 20230709).

[0090] The cement is mixed with the commercial ordinary cement hydration inhibitor in Comparative Example 1 to obtain a second mixed material (the content of the commercial ordinary cement hydration inhibitor in the second mixed material is 0.2 wt%).

[0091] The temperature rise of the single cement, the first mixed material and the second mixed material is tested in a foam box under a constant temperature environment of 20℃, and the temperature rise of the single cement, the first mixed material and the second mixed material is obtained, as shown in Figure 1 From Figure 1 it can be seen that, on the one hand, compared with the second mixed material, the first mixed material significantly reduces the temperature rise of cement hydration, and the first mixed material achieves a lasting temperature reduction effect, which may be due to the fact that the commercial ordinary cement hydration inhibitor in the second mixed material has a one-time temperature reduction effect, while the microcapsule sustained-release material in the first mixed material has a three-stage release, achieving a lasting and excellent temperature reduction effect; on the other hand, compared with the second mixed material, the first mixed material does not substantially affect the setting of the cement. This shows that the microcapsule sustained-release material prepared in Example 1 can significantly inhibit the temperature rise of cement hydration without substantially delaying the setting, and has a lasting and excellent temperature reduction effect.

[0092] (2) The cement is mixed with the microcapsule sustained-release material prepared in Example 2 to obtain a third mixed material (the content of the microcapsule sustained-release material in the third mixed material is 0.2 wt%), and the temperature rise of the single cement and the third mixed material is tested in a foam box under a constant temperature environment of 20℃, and the temperature rise of the single cement and the third mixed material is obtained, as shown in Figure 2 From Figure 2 it can be seen that the microcapsule sustained-release material prepared in Example 2 can significantly inhibit the temperature rise of cement hydration without substantially affecting the setting of the cement, and has a lasting and excellent temperature reduction effect.

[0093] (3) The cement is mixed with the microcapsule sustained-release material prepared in Example 3 to obtain a fourth mixed material (the content of the microcapsule sustained-release material in the fourth mixed material is 0.2 wt%), and the temperature rise of the single cement and the fourth mixed material is tested in a foam box under a constant temperature environment of 20℃, and the temperature rise of the single cement and the fourth mixed material is obtained, as shown in Figure 3 FromFigure 3 As can be seen from Example 3, the microcapsule sustained-release material can significantly inhibit the temperature rise of cement hydration without significantly affecting cement setting, and has a long-lasting and excellent temperature suppression effect.

[0094] (4) The cement used is Jidong Cement (P·O 425, production batch 20231105). The cement is mixed with the microcapsule sustained-release material prepared in Example 1 to obtain the fifth mixed material (the amount of microcapsule sustained-release material in the fifth mixed material is 0.2wt%).

[0095] The cement was mixed with the temperature-suppressing material in Comparative Example 2 to obtain the sixth mixture (the amount of slow-release material in the sixth mixture was 0.2 wt%).

[0096] Under a constant temperature of 20℃, the temperature rise of single cement, the fifth mixture, and the sixth mixture was tested in a foam box, and the resulting schematic diagrams of the temperature rise of single cement, the fifth mixture, and the sixth mixture are shown below. Figure 4 As shown. From Figure 4 As can be seen, compared to the sixth mixture, the fifth mixture further reduces the temperature rise of cement hydration and has virtually no impact on setting. This further demonstrates that the microcapsule material prepared by adding porous carbon material and hot melt adhesive film has a multi-stage slow-release effect, achieving excellent temperature suppression while essentially not affecting setting.

[0097] Experimental Example 2

[0098] According to the mix proportions in Table 1 (using Jidong Cement (P·O 425, production batch 20231105), and polycarboxylate superplasticizer with a water reduction rate of 30%), concrete specimens 1 and 2, each measuring 1500mm × 150mm × 150mm, were prepared in the laboratory. Concrete specimens 1 and 2 were then subjected to temperature and stress tests using a temperature and stress testing machine (HYTSTM-II type manufactured by Beijing Hangyuan Pingyang Technology Development Co., Ltd.). Temperature and stress curves for the two types of concrete specimens were obtained, as shown in the figure. Figure 5 As shown; Figure 5 In the graph, the red and black lines represent temperature curves; the blue and green lines represent stress curves.

[0099] Table 1 Concrete Mix Proportions

[0100]

[0101] from Figure 5As can be seen from the table, the maximum temperature of the concrete test piece 2 is reduced by ΔT1-10.8℃ compared with the concrete test piece 1, which proves that the microcapsule slow-release material has a good peak shaving effect. With the temperature reduction, at a certain moment, the tensile stress of the concrete test piece will exceed the tensile strength of the concrete, and the constrained test piece will crack. The cracking temperature represents the cracking trend of the tested concrete and is a comprehensive evaluation index of factors such as temperature history, elastic modulus, stress relaxation, tensile strength, etc. The lower the cracking temperature, the smaller the cracking risk, and the smaller the trend of early-age thermal cracks. From the table, it can be seen that the cracking temperature of the concrete test piece 2 is reduced by ΔT2 compared with the concrete test piece 1. The concrete test piece 1 cracks at 21℃, and the cracking temperature of the concrete test piece 2 after adding the microcapsule slow-release material is reduced to about 0℃, which has excellent effect of inhibiting the temperature shrinkage cracking of concrete. Figure 5 As can be seen from the table, the cracking stress of the concrete test piece 2 is reduced by ΔT2 compared with the concrete test piece 1. The cracking stress of the concrete test piece 1 is 2.5MPa, and the cracking stress of the concrete test piece 2 after adding the microcapsule slow-release material is reduced to about 2.5MPa, which has excellent effect of inhibiting the temperature shrinkage cracking of concrete. Figure 5 As can be seen from the table, the stress levels of the two are similar, both about 2.5MPa, which shows that the microcapsule slow-release material has almost no effect on the ultimate tensile strength of the concrete.

[0102] Obviously, the above examples are only examples for the purpose of clear illustration, and are not limitations on the embodiments. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description. All the embodiments do not need to be exhausted here. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A microcapsule sustained release material, characterized by, The microcapsule slow-release material comprises a core and a coating layer; the core comprises a porous carbon material and a temperature-inhibiting material, and the coating layer is a hot melt adhesive film; The mass ratio of the temperature-inhibiting material, the porous carbon material and the hot melt adhesive film is (55-80):(40-50):(3-5); The temperature-inhibiting material comprises modified starch. The modified starch comprises hydroxypropyl distarch phosphate, sodium octenyl succinate starch and yellow dextrin. The mass ratio of the hydroxypropyl distarch phosphate, the sodium octenyl succinate starch and the yellow dextrin is (10-20):(15-20):(30-40).

2. The microencapsulated slow release material of claim 1, wherein, The particle size of the microcapsule slow-release material is 0.05-0.6 mm.

3. The microencapsulated slow release material of claim 1, wherein, The porous carbon material comprises one or more of activated carbon, carbon nanotubes, carbon aerogel and biochar.

4. The microencapsulated slow release material of claim 3, wherein, The biochar comprises sludge-derived carbon material.

5. The microencapsulated slow release material of claim 4, wherein, The preparation method of the sludge-derived carbon material comprises the following steps: sintering sludge under a protective atmosphere to obtain sludge-derived carbon material.

6. The microencapsulated slow release material of claim 1, wherein, The melting point of the hot melt adhesive film is 50-65℃.

7. The microencapsulated slow release material of claim 1, wherein, The hot melt adhesive film is a TPU hot melt adhesive film.

8. Process for the preparation of microencapsulated slow release materials according to any one of claims 1 to 7, characterized in that, The method comprises the following steps: Mixing the temperature-inhibiting material, the porous carbon material and water, and granulating to obtain granules; Mixing the granules with the hot melt adhesive film in a molten state to obtain the microcapsule slow-release material.

9. The method of claim 8, wherein the microencapsulated slow release material is prepared by a process comprising: The step of mixing the temperature-inhibiting material, the porous carbon material and water, and granulating to obtain granules comprises: Mixing the temperature-inhibiting material and water to obtain a first mixture; Heating the first mixture to a target temperature, mixing with the porous carbon material to obtain a second mixture, and then granulating to obtain the granules.

10. The method of claim 9, wherein the microencapsulated slow release material is prepared by a process comprising: The mass solid content of the first mixture is 25-35%.

11. The method of claim 9 or 10, wherein the microencapsulated slow release material is prepared by a process comprising: The target temperature is 50-60℃.

12. The method of claim 8, wherein the microencapsulated sustained release material is prepared by a process comprising: The hot melt adhesive film in a molten state is obtained by preheating the hot melt adhesive film.

13. The method of claim 12, wherein the microencapsulated slow release material is prepared by a process comprising: The preheating temperature is 90-110℃.

14. The method of claim 8, wherein the microencapsulated slow release material is prepared by a process comprising: The rotation speed of the granules mixed with the hot melt adhesive film in a molten state is 250-350 r / min.

15. The microcapsule slow-release material of any one of claims 1-7 or the microcapsule slow-release material prepared by the preparation method of any one of claims 8-14 is applied to control temperature shrinkage cracking of concrete.

16. The use according to claim 15, characterized in that, The concrete comprises tunnel lining concrete, subway pipe gallery side wall concrete or civil engineering basement outer wall concrete.

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