Method for preparing self-repairing cement-based materials with hydroxide as core microcapsules

Abstract

The present application relates to a kind of cement-based self-repairing technology, and self-repairing microcapsule is prepared by encapsulating hydroxide particles, and the prepared microcapsule is added to mortar to prepare self-repairing mortar capable of realizing crack self-healing, which significantly improves the durability and service life of cement-based materials.The method for packaging hydroxide and preparing self-repairing mortar are proposed.The microcapsule can release the core material by stress cracking and soaking in pore solution, and the core material hydroxide reacts to fill the crack, restoring the performance of mortar.

Description

Technical Field

[0001] This invention relates to a cement-based self-healing technology, which prepares self-healing microcapsules by encapsulating hydroxide particles, and adds the prepared microcapsules to mortar to prepare a self-healing mortar that can achieve self-healing of cracks, significantly improving the durability and service life of cement-based materials. Background Technology

[0002] During long-term service, cement-based materials develop microcracks due to factors such as load, shrinkage, and temperature changes. These microcracks provide channels for harmful ions to invade, accelerating material deterioration and seriously threatening structural durability and service life. To proactively address this issue, self-healing technology has emerged, among which microcapsule-based repair systems have attracted much attention due to their intelligent characteristics of "crack triggering and targeted release." Self-healing microcapsules are mainly divided into organic and inorganic repair systems based on the type of encapsulating repair agent. Organic healing systems often use liquid organic substances such as epoxy resin and isocyanate as repair agents, offering advantages such as rapid repair reaction and high bonding strength. However, these organic core materials have poor compatibility with the cement matrix, insufficient long-term stability, and are prone to aging; furthermore, high dosages can damage the mechanical properties of the matrix. Inorganic repair systems mainly include two categories: microbial-induced mineralization and mineral admixtures. Microbial remediation technology is limited by the survival rate of microorganisms in the highly alkaline environment of cement, nutrient supply, and a slow repair rate. While mineral-based remediation agents such as sodium silicate and magnesium oxide have good compatibility with the matrix, their release timing and reaction process are difficult to control precisely, resulting in unstable repair efficiency. Hydroxides, with their stable chemical properties, can exist stably in the pore solutions of cement-based materials for extended periods. Furthermore, they can effectively fill cracks through chemical reactions such as carbonation, making them an ideal inorganic remediation agent. Compared to traditional remediation agents, hydroxide remediation agents offer long-term storage stability. However, directly incorporating hydroxides into cement-based materials can affect the hydration of cement clinker. Encapsulating hydroxides to form novel microcapsules that combine good intrinsic properties with highly efficient self-repairing capabilities is of significant value in promoting the application of self-healing technology.

[0003] Chinese patent CN202210460927.8 describes a method for preparing expandable self-healing microcapsules. The method uses an inorganic composite powder as the core material (bentonite repair agent + clay curing agent + MgO expander), and ethyl cellulose or polyvinyl alcohol as the wall material. Chloride ion triggering agents (such as cuprous chloride) are incorporated into the capsule wall to create self-healing microcapsules. This allows the microcapsules to be stress-triggered and chemically triggered, resulting in repair products that are homogeneous in composition and structure with the cement matrix (forming ettringite, etc.), exhibiting good compatibility. MgO reacts with water to generate Mg(OH)2, providing expansion pressure and enhancing the filling effect. However, ethyl cellulose and polyvinyl alcohol dissolve rapidly in water, causing premature release of magnesium oxide, which leads to poor stability of the cement matrix.

[0004] Chinese patent CN202210368184.1 proposes a method to encapsulate ordinary cement particles using paraffin wax as the main wall material and isocyanate through interfacial polymerization, solving the problems of poor compatibility of liquid repair agents and difficulty in encapsulating solid repair agents. While this method achieves the repair of cement cracks with cement, the encapsulated cement particles have low activity, and the capsule walls may be porous, resulting in unsatisfactory crack repair efficiency and self-healing effect.

[0005] Chinese patent CN202410391235.1 uses activated granular cement as its core and leverages an expansive agent (bentonite / UEA) to improve the self-healing of cracks in ordinary cement-based materials. The retarder slows down premature hydration and consumption of cement, exhibiting good homogeneity and compatibility; however, the long-term storage stability of the activated cement particles (prevention of prehydration) remains a challenge.

[0006] To address this, we propose using microencapsulation technology to encapsulate hydroxides, then mixing the microcapsules into cementitious substrates. When microcracks occur, the hydroxides react to generate carbonate / gel layer precipitates, which fill the microcracks and restore the impermeability and compressive strength of the cementitious substrates. Summary of the Invention

[0007] Addressing the current limitations of microcapsule technology, this invention proposes a method for encapsulating hydroxides and preparing self-healing mortar. The microcapsules can release the core material through stress fracture and immersion in a pore solution. The hydroxide in the core material then undergoes a chemical reaction to fill the cracks, restoring the various properties of the mortar.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is summarized as follows:

[0009] This invention first proposes a method for encapsulating hydroxide microcapsules. This method mainly includes two core steps:

[0010] 1) Granulation and pretreatment of core material: One or more hydroxide powders are mixed with a binder polyvinylpyrrolidone (PVP) ethanol solution at a ratio of 10:1, wherein the concentration of the PVP ethanol solution is 10 wt%~50 wt%. After being pressed into shape by a 100.0 kN press, it is dried at 30℃~60.0℃ for 24 h. The bulk material can be dried in a vacuum oven at 65~70℃ to adsorb organic additives, which facilitates granulation. After drying at room temperature, it is crushed and screened to obtain core material particles with a particle size range of 50~1000 μm. In order to encapsulate the core material particles, the particle surface is pretreated (the particles are moistened by adding m-phenylenediamine ethanol solution and dried at room temperature, and sprayed at a core material particle:solution = 1:1).

[0011] 2) Microcapsule encapsulation: Using a process combining interfacial polymerization and melt condensation, the pretreated particles are wetted with an oil phase and reacted in an aqueous phase at 65~75 ℃ in a water bath at a speed of 400~800 r / min for 5~15 minutes. Then, ice water is added for cooling and solidification. After washing with anhydrous ethanol 3~4 times and drying in air for 24 hours, hydroxide core material microcapsules with a core-shell structure are formed.

[0012] Wherein, the hydroxide mentioned in 1) may be at least one of calcium hydroxide, magnesium hydroxide, aluminum hydroxide, zinc hydroxide, barium hydroxide, strontium hydroxide, and copper hydroxide, preferably calcium hydroxide.

[0013] The organic additives adsorbed by the core material block are one of polyethylene glycol, glyceryl tristearate, and sliced ​​paraffin. These powders are heated to 70-80 °C and melted into a liquid, then adsorbed in a vacuum oven for 30-60 minutes. The broken hydroxide particles are between 50.0 and 1000.0 μm. An auxiliary expanding agent can also be used instead of the core material hydroxide; this expanding agent is one of sodium polyacrylate / sodium sulfonate superabsorbent resin (SAP), calcium-based bentonite, or kaolin. The mass ratio of core material hydroxide to expanding agent is 9:1 to 5:5.

[0014] Step 2), the wall material includes, but is not limited to, one or more of isocyanates, tristearate, chipped paraffin, microcrystalline wax, polyethylene wax, beeswax, etc. 2) The oil phase is prepared from isophorone diisocyanate, glycerides or waxes, surfactant Span 85, and solvent toluene; wherein, based on the total mass of the oil phase, it contains 1-3 parts isocyanate, 4 parts glycerides or waxes, Span 85 is 1.0-4.5 wt% of the oil phase mass, toluene is 1.0 wt%-4.5 wt% of the oil phase mass, and the emulsification temperature is 55-75 ℃; in the aqueous phase, the surfactant SDBS is 0.5 wt%-2.25 wt% of the aqueous phase mass, and gum arabic powder is 0.25 wt%-0.50 wt% of the aqueous phase mass.

[0015] 3) Preparation of self-healing cement-based materials

[0016] The microcapsule dosage is 0.0 wt% to 15.0 wt% of the cement mass. The water to cementitious material mass ratio is 0.27 to 0.5, and the cementitious material to ISO standard sand mass ratio is 1:3. The cementitious material is silicate cement, or silicate cement mixed with steel slag (main component is dicalcium silicate), Class F fly ash (main component is silicon dioxide / aluminum), and granulated blast furnace slag (main component is silicate mineral) in a mass ratio of 6:2:1:1.

[0017] 4) Self-healing performance and effect test: Microcapsules achieve self-healing in cement-based materials. Hydroxides released from microcapsules generate carbonate precipitates or composite gel layers through chemical reactions such as carbonation, which fill the microcracks in cement-based materials and achieve self-healing of the impermeability and compressive strength of cement-based materials. Attached Figure Description

[0018] Figure 1 It is a calcium hydroxide microcapsule, in which Figure 1 a. Microscopic morphology of dispersed microcapsules; Figure 1 b. Morphology of individual microcapsules; Figure 1 Cross-sectional structure of c microcapsules; Figure 1 Magnified view of the capsule wall structure of d microcapsules;

[0019] Figure 2 The image shows calcium hydroxide microcapsules, where a is the infrared spectrum of the calcium hydroxide microcapsules and b is the TG curve of the calcium hydroxide microcapsules.

[0020] Figure 3 Examples 1-6 illustrate the effect of different calcium hydroxide microcapsules on the recovery of compressive strength in self-healing mortar;

[0021] Figure 4 The images show a comparison of crack repair effects, where a1a2 are comparison images of mortar without microcapsules for crack repair; b1b2 are comparison images of mortar with 10.0 wt% microcapsules for crack repair in Example 4.

[0022] Figure 5 The images show the repair effects of mortar cracks, where a is a comparison image of mortar crack repair without microcapsules; b is the repair effect image of mortar crack repair with 15.0wt% microcapsules in Example 5.

[0023] Figure 6 Comparison images of mortar crack repair; where a is a comparison image of mortar crack repair without microcapsules; b is a comparison image of mortar crack repair effect with 10.0wt% microcapsules in Example 8;

[0024] Figure 7 To demonstrate the self-healing effect and impermeability restoration of Examples 2, 3, and 4, a 10 g water flux test process is shown. Detailed Implementation

[0025] To further illustrate the technical means and experimental effects adopted by the present invention to achieve the intended purpose, the present invention will be further described in detail below with reference to embodiments and results, but the present invention is not limited thereto.

[0026] Example 1

[0027] A method for preparing calcium hydroxide microcapsules and self-healing mortar, the specific experimental steps of which are as follows:

[0028] 1) Granulation of calcium hydroxide microparticles

[0029] Weigh 100.0 g of calcium hydroxide powder and mix it evenly with 10.0 g of PVP ethanol solution (mass fraction 20.0 wt%). Apply 100.0 kN pressure using a press to form a round cake, and dry it at 60 ℃. Immerse the core material block in molten PEG at 65.0 ℃ for 30 minutes to fully adsorb, facilitating subsequent grinding and granulation. After removal, dry at room temperature (all room temperature mentioned throughout the text refers to ambient temperature, not temperature control), crush using a crusher, and sieve out 10.0 g of particles ranging from 100 to 300 μm. Add 10.0 g of 25.0 wt% m-phenylenediamine ethanol solution dropwise to the particle surface to wet it, and dry at room temperature for 24 hours for later use.

[0030] 2) Encapsulation of calcium hydroxide microcapsules

[0031] Weigh 12.0 g of glyceryl tristearate, 0.75 g of Span 85, 4.1 g of isoflurane diisocyanate (IPDI), 1.0 g of 2644, and 0.75 g of toluene, and mix them to form the oil phase. Heat the mixture in a water bath at 65.0 °C until melted. Add 10.0 g of the particles prepared in step 1) to the oil phase to impregnate it. Separately, take 400.0 mL of deionized water, add 9.0 g of SDBS, 3.0 g of gum arabic powder, and 3.0 g of TEPA to form an aqueous phase. Heat the aqueous phase in a water bath to 65.0 °C and stir at 600 r / min to form a continuous phase. Pour the impregnated particles and the oil phase into the aqueous phase and disperse for 15 min. Then add cold water to rapidly cool the system and solidify the capsule walls. After filtration, washing, and drying, calcium hydroxide microcapsules are obtained.

[0032] 3) Preparation of self-healing mortar

[0033] With a water-cement ratio of 0.5 and a mortar-cement ratio of 1:3, 450.0 g of silicate cement (P·I 42.5), 225.0 g of tap water, 1350.0 g of standard sand, and 22.5 g of microcapsules (10.0 wt% of cement mass) were weighed and mixed evenly using a mortar mixer. The mixture was poured into molds, cured for 24 hours, demolded, and then cured in a water tank for 28 days. To study the crack healing effect, PVA short fibers (0.5 wt% of cement mass, 6 mm in length and 20 μm in diameter, manufactured by Anhui Wanwei Group Co., Ltd.) were added to the mortar matrix to control crack size. After 28 days of curing, pre-cast cracks were placed in a curing chamber for 7 days of repair and curing, and the crack closure was observed under a microscope. The water flux test was used to assess the impermeability of the self-healing mortar cracks. The mortar was subjected to pre-compression failure to test its strength and recovery performance.

[0034] The results showed that the obtained microcapsule structure was stable. Compared with the control group, the mortar containing 5.0 wt% microcapsules had a 28-day compressive strength that was about 9.5% higher than that of the control group. After pre-compression damage, the test blocks, after curing for 7 days, showed a compressive strength recovery rate of over 100.9%. For 100 μm cracks, calcium carbonate filling the cracks resulted in near-closure after 7 days of repair, with a water permeability recovery rate of 60% (i.e., a 60% reduction in water permeability).

[0035] Example 2

[0036] A method for preparing calcium hydroxide microcapsules and self-healing mortar, the specific experimental steps of which are as follows:

[0037] 1) Granulation of calcium hydroxide microparticles

[0038] Weigh 100.0 g of calcium hydroxide powder and mix it evenly with 10.0 g of PVP ethanol solution (mass fraction 20.0 wt%). Apply 100.0 kN of pressure slowly using a press to form round cakes, which are then dried at 60 ℃. Immerse the cakes in molten PEG at 65.0 ℃ for full adsorption, facilitating subsequent granulation. After removal, dry at room temperature, crush using a crusher, and sieve to obtain particles of 300–600 μm. Add 10.0 g of 25.0 wt% m-phenylenediamine ethanol solution dropwise to the particle surface to wet it, and dry at room temperature for 24 hours for later use.

[0039] 2) Encapsulation of calcium hydroxide microcapsules

[0040] As in Example 1.

[0041] 3) Preparation of self-healing mortar

[0042] Set the water-cement ratio to 0.5 and the mortar-cement ratio to 1:3, and weigh out 5.0 wt% of cement microcapsules, as in Example 1.

[0043] The results showed that the obtained microcapsule structure was stable. The mortar containing 5.0 wt% microcapsules exhibited a 28-day compressive strength approximately 19.4% higher than the control group. After pre-compression damage, the test blocks, after 7 days of curing, showed a compressive strength recovery rate of over 95.1%. For 100 μm cracks, calcium carbonate filling the crack site resulted in near-closure after 7 days, with a 50% recovery rate of water permeability (i.e., a 50% reduction in water permeability).

[0044] Example 3

[0045] A method for preparing calcium hydroxide microcapsules and self-healing mortar, the specific experimental steps of which are as follows:

[0046] 1) Granulation of calcium hydroxide microparticles

[0047] Weigh 100.0 g of calcium hydroxide powder and mix it evenly with 10.0 g of PVP ethanol solution (mass fraction 20.0 wt%). Apply 100.0 kN of pressure slowly using a press to form round cakes, and dry them at 60 ℃. Immerse the cakes in molten PEG at 65.0 ℃ for full adsorption, facilitating subsequent granulation. After removal, dry at room temperature, crush using a crusher, and sieve to obtain particles of 600–900 μm. Add 10.0 g of 25.0 wt% m-phenylenediamine ethanol solution dropwise to the particle surface to wet it, and dry at room temperature for 24 hours for later use.

[0048] 2) Encapsulation of calcium hydroxide microcapsules; 3) Preparation of self-healing mortar. A water-cement ratio of 0.5 and a mortar-cement ratio of 1:3 were set. 5.0 wt% of cement was weighed into microcapsules, as in Example 1.

[0049] The results showed that the microcapsules had good stability, and the compressive strength of the self-healing mortar was about 7.3% higher than that of the control group. After pre-compression failure, it could achieve a compressive strength recovery rate of more than 99.5%. After 7 days of healing repair, it could complete the filling and closure of 100 μm level cracks, with calcium carbonate filling the cracks and water impermeability recovery reaching more than 40.0%.

[0050] Example 4

[0051] A method for preparing calcium hydroxide microcapsules and self-healing mortar, the specific experimental steps of which are as follows:

[0052] 1) Granulation of calcium hydroxide microparticles, sieved to obtain particles of 600~900 μm; 2) Encapsulation of calcium hydroxide microcapsules; 3) Preparation of self-healing mortar. A water-cement ratio of 0.5 and a mortar-cement ratio of 1:3 were set. 10.0 wt% of calcium hydroxide microcapsules (based on the cement mass) were weighed, as in Example 1.

[0053] The results showed that the microcapsules had good stability, and the compressive strength of the self-healing mortar was increased by about 8.9% compared with the control group, but it could still achieve efficient crack repair. After pre-compression failure, it could achieve a compressive strength recovery rate of more than 95.8%. After 7 days of healing repair, it could complete the filling and closure of 100 μm level cracks, with calcium carbonate filling the crack and the impermeability recovery reaching more than 80.0%.

[0054] Example 5

[0055] A method for preparing calcium hydroxide microcapsules and self-healing mortar, the specific experimental steps of which are as follows:

[0056] 1) Granulation of calcium hydroxide microparticles, 2) Encapsulation of calcium hydroxide microcapsules, 3) Preparation of self-healing mortar. A water-cement ratio of 0.5 and a mortar-cement ratio of 1:3 were set. Microcapsules weighing 15.0 wt% of cement were prepared, as in Example 1.

[0057] The results showed that the microcapsules had good stability. The compressive strength of the self-healing mortar decreased by about 16.8% compared with the control group, but it could still achieve efficient crack repair. After pre-compression failure, it could achieve a compressive strength recovery rate of more than 98.3%. After 7 days of healing repair, it could complete the filling and closure of 100 μm level cracks. The crack was filled with calcium carbonate, and the impermeability was restored to more than 80.0%.

[0058] Example 6

[0059] A method for preparing calcium hydroxide microcapsules and self-healing mortar, the specific experimental steps of which are as follows:

[0060] 1) Granulation of calcium hydroxide microparticles, sieved to obtain particles of 600~900 μm; 2) Encapsulation of calcium hydroxide microcapsules; 3) Preparation of self-healing mortar. A water-cement ratio of 0.5 and a mortar-cement ratio of 1:3 were set, and 5.0 wt% of cement was weighed into microcapsules. After curing the prepared self-healing mortar for 90 days, pre-cracks were created and placed in a humid indoor environment. Tap water was added periodically, and the crack closure was observed under a microscope. (See Example 1.)

[0061] The results showed that the microcapsules had good stability and could still exert a self-repair effect after long-term maintenance. The microcapsules could complete the filling and closure of 100 μm level cracks within 7 days. The cracks were filled with calcium carbonate, and the impermeability was restored by more than 30.0%.

[0062] Example 7

[0063] A method for preparing magnesium hydroxide microcapsules and self-healing mortar, the specific experimental steps of which are as follows:

[0064] 1) Granulation of magnesium hydroxide microparticles; 2) Encapsulation of magnesium hydroxide microcapsules; 3) Preparation of self-healing mortar. A water-cement ratio of 0.5 and a mortar-cement ratio of 1:3 were set. Microcapsules weighing 5.0 wt% of cement were prepared, as in Example 1.

[0065] The results showed that the microcapsules had good stability, the self-healing mortar had higher compressive strength than the control group, and the compressive strength could be restored after pre-compression failure. The mortar could complete the filling and closure of 100 μm cracks after 7 days of healing and repair. The crack was filled with magnesium silicate / silicate gel, and the water impermeability was restored to 50.0%.

[0066] Example 8

[0067] A method for preparing calcium hydroxide microcapsules and self-healing mortar, the specific experimental steps of which are as follows:

[0068] 1) Granulation of calcium hydroxide microparticles; 2) Encapsulation of calcium hydroxide microcapsules. Example 1.

[0069] 3) Preparation of self-healing mortar using multi-solid waste cementitious materials. The water-cement ratio was set at 0.27, and the cementitious material was prepared by mixing cement, steel slag, fly ash, and slag in a ratio of 6:2:1:1, with a mortar-cement ratio of 1:3. Specifically, the following steps were taken: 270.0g of silicate cement (P·I42.5), 90.0g of steel slag, 45.0g of fly ash, 45.0g of blast furnace slag, 225.0g of tap water, 1350.0g of standard sand, and 45.0g of microcapsules (10.0 wt% of cement mass) were weighed out and mixed evenly using a mortar mixer. The mixture was then poured into a mold, cured for 24 hours, demolded, and cured in a water tank for 28 days. For the study of self-healing cracks, 0.5 wt% of PVA fiber was added to the cement to control the width of the precast cracks. After 28 days, cracks were created using a press, and tap water was dripped onto the surface of the cement block exposed to an indoor environment. The closure of the crack surface was observed using a microscope and an optical camera.

[0070] The results showed that the microcapsules had good stability, and after pre-compression, they could achieve a compressive strength recovery rate of over 90.0%. After 7 days of healing and repair, they could complete the filling and closure of 300μm-level cracks, and the water impermeability recovery reached over 40.0%.

[0071] Example 9

[0072] The preparation of a self-healing ultra-high performance concrete (UHPC) involves the following experimental steps:

[0073] 1) Granulation of calcium hydroxide microparticles

[0074] Weigh out 70.0g of calcium hydroxide powder, 30.0g of SAP and 10.0g of PVP solution and mix them as in Example 1.

[0075] 2) Encapsulation of calcium hydroxide microcapsules

[0076] As in Example 1.

[0077] 3) Preparation of self-healing mortar

[0078] The water-cement ratio was set to 0.27, and the mortar-cement ratio to be 1:3. Calcium hydroxide SAP microcapsules (10.0 wt% of cement mass) were added, as in Example 1.

[0079] The results showed that the microcapsules had good stability, and the compressive strength of the self-healing mortar was 2.6% higher than that of the control group. After pre-compression, it could achieve a 90% recovery rate of compressive strength. It could complete the filling and closure of 100 μm level cracks in 7 days of healing and repair. The cracks were filled with calcium carbonate and SAP gel, and the impermeability was completely restored.

Claims

1. A method for preparing hydroxide core microcapsules, characterized in that, The core process includes two steps: core material granulation and pretreatment, and microcapsule encapsulation. The specific steps are as follows: 1) Granulation and pretreatment of core material: Hydroxide powder or hydroxide composite is mixed with polyvinylpyrrolidone (PVP) solution at a mass ratio of 10:1, pressed into shape by a press, dried at 30℃~60℃, then crushed and screened to obtain particles with a particle size of 50.0~1000.0μm, and m-phenylenediamine ethanol solution is added to the surface of the particles and dried. 2) Microcapsule encapsulation: The dried particles are added to the oil phase for wetting. The wetted particles and oil phase are then poured into the aqueous phase, dispersed in the aqueous phase, and reacted in a water bath at 55~75℃ for 5-10 minutes. The mixture is then cooled and solidified with ice water. After washing with anhydrous ethanol 3-4 times and drying, core-shell structured hydroxide core material microcapsules are obtained.

2. The preparation method according to claim 1, characterized in that: The hydroxide is at least one of calcium hydroxide, magnesium hydroxide, aluminum hydroxide, zinc hydroxide, barium hydroxide, strontium hydroxide, and copper hydroxide.

3. The preparation method according to claim 1, characterized in that: Add 1 to 5 parts of auxiliary expansion material to the core material. The auxiliary expansion material is one of the following: water-absorbing resin SAP, bentonite, and kaolin.

4. The preparation method according to claim 1, characterized in that: The microcapsule particles obtained by screening have particle sizes of 100~300μm, 300~600μm, or 600~900μm.

5. The preparation method according to claim 1, characterized in that: The oil phase includes isophorone diisocyanate, glycerides, or waxes; it also includes surfactant Span 85 and solvent toluene; the oil phase mass ratio of isocyanate to glycerides or waxes is between 2:8 and 4:6; the amount of surfactant Span 85 added is 1.0 to 4.5 wt% of the total oil phase mass, the amount of solvent toluene is 1.0 wt% to 4.5 wt% of the oil phase mass, and the emulsification temperature is 55 to 75 °C; the aqueous phase contains surfactant SDBS at 0.5 wt% to 2.25 wt% of the aqueous phase mass and gum arabic powder at 0.25 wt% to 0.50 wt% of the aqueous phase mass.

6. Microcapsules obtained by the preparation method according to claim 1.

7. The application of the microcapsules according to claim 5, characterized in that: The microcapsule dosage is 5.0wt%~15.0wt% of the cement mass, the water-cement ratio is 0.27~0.5, and the mortar-cement ratio is 1:3; the cementing material is silicate cement, or a multi-solid waste composite cementing material composed of silicate cement, steel slag, fly ash, and blast furnace slag in a mass ratio of 6:2:1:1.

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