Cement-based permeable nanocrystal self-repairing waterproof coating and preparation method thereof

Abstract

The invention discloses a cement-based permeable nanocrystal self-repairing waterproof coating and a preparation method thereof. The cement-based permeable nanocrystal self-repairing waterproof coating comprises a cement-based matrix; infiltrating the nanocrystal particles; the cadmium sulfide quantum dots are dispersed in the coating according to the mass ratio of 1-5% and have a dual-wavelength light-operated self-repairing mechanism, ultraviolet light (320-400 nm) triggers surface layer repairing, when the ultraviolet light is received, surface layer nanocrystal particles are driven to repair cracks with the width smaller than or equal to 0.2 mm within one hour, the anti-permeability pressure of mortar with a coating after repairing is larger than or equal to 1.5 MPa, and the anti-permeability pressure of the mortar with the coating is larger than or equal to 1.5 MPa; according to the present invention, the ultraviolet light triggers the surface layer rapid crystallization (the sealing is less than or equal to 0.2 mm crack within 1 h) and the infrared light drives the deep penetration (the penetration depth is more than or equal to 1.5 mm), such that the problems that the traditional coating depends on the moisture triggering and the deep repair ability is insufficient are solved, and the active repair effect of the surface layer rapid repair and the deep reinforcement is achieved; the impermeability is broken through, and the secondary impermeability pressure at 56 days is larger than or equal to 2.0 MPa and is obviously higher than that of a conventional self-repairing coating.

Description

Technical Field

[0001] The present invention belongs to the technical field of cement materials, and in particular relates to a cement-based penetrating nano-crystallization self-repairing waterproof coating and a preparation method thereof. Background Art

[0002] Cement-based penetrating nano-crystalline waterproof coatings are widely used in the field of building waterproofing due to their "penetrating crystallization + self-repairing" characteristics. Existing technologies mainly achieve self-repair of cracks under the guidance of moisture through the synergistic effect of cement-based matrix and penetrating nano-crystalline particles: when the coating encounters cracks or water seepage, the nano-crystalline particles penetrate into the pores of the base layer with the water, and generate insoluble crystals through hydration reactions to fill the cracks, thereby restoring the waterproof performance. This type of coating has the advantages of good compatibility with cement-based substrates and high long-term waterproof reliability. It is widely used in basements, kitchens, bathrooms, bridges and other scenes. Conventional products usually improve the anti-seepage pressure, bonding strength and other properties by optimizing the nano-crystalline composition, adjusting the mix ratio, and gradually introduce functional additives to expand weather resistance or construction convenience, forming a relatively mature technical system.

[0003] However, the existing technology still has room for improvement in many aspects: First, the repair mechanism relies on moisture triggering, and it is difficult to actively start repair in a dry environment, and the effect of repairing deep cracks is limited; second, the environmental adaptability is insufficient. Conventional coatings decrease in low temperature below -10°C or high temperature above 40°C, and the activity of nanocrystallization decreases, resulting in a significant attenuation of the repair efficiency and mechanical properties of the coating; third, the function is relatively single, lacking composite functions such as antibacterial and heat insulation, and it is difficult to meet the diversified needs of modern buildings for health and energy saving; fourth, the dispersion stability problem of nano-scale components in cement-based matrices has not been completely solved, and agglomeration may lead to a decrease in light / heat response efficiency, affecting long-term performance. In addition, the existing preparation process has insufficient control accuracy for nanoparticle modification and mixing uniformity, which restricts the consistency of product performance and industrial production efficiency. In response to the above problems, it is urgent to develop a new cement-based waterproof coating with an active repair mechanism, full temperature range adaptability and functional expansion. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present invention provide a cement-based penetrating nano-crystallized self-repairing waterproof coating and a preparation method thereof, which solves the problems of the prior art such as dependence on moisture for repair, poor environmental adaptability, single function and dispersed process.

[0005] To achieve the above object, the present invention provides the following technical solutions: Cement-based penetrating nano-crystallized self-repairing waterproof coating, including: cement-based matrix; Penetrating nanocrystalline particles; Cadmium sulfide quantum dots are dispersed in the coating at a mass ratio of 1-5% and have a dual-wavelength light-controlled self-repair mechanism: Ultraviolet light (320-400nm) triggers surface repair: When exposed to ultraviolet light, the surface nanocrystalline particles are driven to repair cracks ≤0.2mm in width within 1 hour. After repair, the anti-seepage pressure of the coated mortar is ≥1.5MPa, which is more than 30% higher than the control group containing only penetrating nanocrystalline particles. Infrared light (800-1200nm) drives deep penetration: When receiving infrared light, it promotes the migration of nano-crystalline particles into the deep layer of the base layer, with a penetration depth of ≥1.5mm and a wet base surface bonding strength of ≥1.5MPa after repair; The dual-wavelength light-controlled self-repair mechanism is used to solve the problem that traditional coatings cannot actively repair deep cracks in a dry environment; The 56d secondary impermeability pressure of the coating is ≥2.0MPa (coated concrete).

[0006] Preferably, the cement-based matrix is silicate cement with a chloride ion content of ≤0.024%; the infiltrated nanocrystalline particles are artificially synthesized calcium silicate hydrate nanocrystals with a Ca / Si molar ratio of 1.5-2.0 and a particle size of 50-200 nm, which are different from the natural hydration products of the cement-based matrix.

[0007] Preferably, the cadmium sulfide quantum dots have a particle size of 1 to 10 nm, a surface grafted γ-aminopropyltriethoxysilane modification layer (thickness 1 to 2 nm), a mass ratio of 10:1 to 5:1 with the coupling agent, an absolute value of the dispersed zeta potential in the coating ≥30 mV, and a light response efficiency of ≥90%.

[0008] Preferably, the control group containing only penetrating nano-crystalline particles has a crystallization rate of 0.15 mm / h under ultraviolet light, while the crystallization rate of the present coating is ≥0.2 mm / h.

[0009] Preferably, the coating further comprises 0.5-2% by mass of nano-silver particles, so that the antibacterial rate of the coating against Aspergillus niger is ≥99%, and the anti-seepage pressure retention rate after UV aging for 2000 hours is ≥85%.

[0010] Preferably, the dual-wavelength light-controlled self-repair mechanism is stably triggered in the temperature range of -20°C to 50°C, and the flexural strength of the coating after repair is ≥6.5MPa (28d), and the flexural strength retention rate is ≥95%.

[0011] Preferably, the preparation method of the cement-based penetrating nano-crystallization self-repairing waterproof coating comprises the following steps: Quantum dot modification: CdS quantum dots were mixed with γ-aminopropyltriethoxysilane coupling agent in a mass ratio of 10:1 to 5:1, and ultrasonically treated at 30-50°C and 200-500W power for 30-60 minutes to obtain modified quantum dots. The photoresponse efficiency was ensured to be ≥95%. Raw material mixing: Mix the cement-based matrix, infiltrated nanocrystalline particles and modified quantum dots at a speed of 2000-3000 r / min for 20-30 minutes, and control the system temperature to ≤40°C; Grinding and homogenizing: Grind the mixture with 0.1-0.5 mm zirconium oxide beads at 25-35° C. for 1-2 hours, until the 0.63 mm sieve residue is ≤5% and the quantum dot dispersion uniformity is ≥95%, thereby obtaining a waterproof coating.

[0012] Preferably, the pH of the ethanol solution in step 1 is adjusted to 8-9, the solvent water-alcohol ratio is 1:4-1:2, and the ultrasound is pulsed (working 30s, resting 10s) to ensure that the surface modification uniformity of the modified quantum dots is ≥90%.

[0013] Preferably, in step 2, the cement-based matrix needs to be dried in advance at 80-100° C. for 2 h, and the moisture content is controlled to be ≤0.5% to avoid competition with the coupling agent for hydrolysis.

[0014] Preferably, after step 3 grinding, the material needs to be tested for absolute value of zeta potential ≥30 mV, pH value 8-9, and photoresponse efficiency ≥90%, otherwise 0.1-0.5 parts of coupling agent is added or the amount of water is adjusted.

[0015] The technical effects and advantages of the cement-based permeable nano-crystallization self-repairing waterproof coating and its preparation method of the present invention are as follows: 1. This invention uses ultraviolet light to trigger rapid crystallization of the surface (sealing cracks ≤ 0.2mm within 1 hour) and infrared light to drive deep penetration (penetration depth ≥ 1.5mm), solving the problem of traditional coatings relying on moisture triggering and insufficient deep repair capabilities, and achieving the active repair effect of "rapid surface repair + deep reinforcement".

[0016] 2. This invention has achieved a breakthrough in anti-seepage performance, with a 56d secondary anti-seepage pressure ≥2.0MPa, which is significantly higher than that of conventional self-healing coatings. Combined with the wet base surface bonding strength ≥1.5MPa, it effectively improves the long-term waterproof reliability of the coating and the base layer.

[0017] 3. This invention has full temperature adaptability, and the repair mechanism is stably triggered within the temperature range of -20℃~50℃. The flexural strength retention rate is ≥95%, breaking through the limitations of traditional coatings on ambient temperature and is suitable for extreme climate scenarios such as severe cold and heat.

[0018] 4. This invention has expanded functional complexities and can be equipped with optional nano-silver particles to achieve an antibacterial rate of ≥99%, taking into account both waterproofing and health needs; quantum dot surface modification technology improves dispersion stability, avoids agglomeration and inactivation, and ensures a light response efficiency of ≥90%.

[0019] 5. This invention optimizes the preparation process and ensures the uniform dispersion of nano-scale components through quantum dot modification, temperature-controlled grinding and other processes. The 0.63mm sieve residue is ≤5%, and the construction performance is excellent, providing stable support for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention provides a flow chart of a cement-based penetrating nano-crystallization self-repairing waterproof coating and a preparation method thereof. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention. It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus. In the absence of further restrictions, the elements defined by the sentence "include..." do not exclude the existence of other identical elements in the process, method, article or apparatus that includes the elements. refer to Figure 1 Cement-based matrix: Conch brand P·O42.5 silicate cement is used. The chloride ion content is tested to be 0.02%, which meets the low chloride content limit in the claims.

[0022] Penetrating nanocrystalline particles: artificially synthesized calcium silicate hydrate nanocrystals produced by Nanjing Xianfeng Nano, with a calcium-silicon molar ratio (Ca / Si) of 1.8, an average particle size of 100nm, and a specific surface area of 80m² / g, which are clearly distinguished from the crystalline products generated by natural hydration of cement.

[0023] Cadmium sulfide quantum dots: synthesized in the laboratory by hydrothermal method, transmission electron microscopy (TEM) showed an average particle size of 5nm, and the surface was modified by γ-aminopropyltriethoxysilane coupling agent.

[0024] Nanosilver particles: purchased from Suzhou Nanotech, with an average particle size of 50nm, are used to give the coating antibacterial function.

[0025] Preparation method: Quantum dot modification: 3 g of cadmium sulfide quantum dots were dispersed in an ethanol solution containing 6 g of a coupling agent (water-to-alcohol volume ratio of 1:3, pH adjusted to 8.5), treated with 300 W pulsed ultrasound (working 30 s, rest 10 s) at 40°C for 45 min, and ethanol was removed by vacuum rotary evaporation (45°C, vacuum degree -0.09 MPa) to obtain modified quantum dot powder (quantum dot to coupling agent mass ratio of 5:1).

[0026] Preparation of premix: 25 g of nanocrystalline particles and 1 g of nanosilver particles were added to a stirring kettle and dry mixed at a speed of 1200 r / min for 15 min to ensure uniform dispersion.

[0027] Composite dispersion: Add 60g of Portland cement to the premix, add 50mL of deionized water dropwise at a rate of 8mL / min while stirring, and add modified quantum dot powder at the same time. Increase the speed to 2500r / min, control the system temperature at 35℃, and continue dispersing for 25min.

[0028] Homogenization: The mixture was transferred to a sand mill and ground using 0.3 mm zirconia beads (65% filling rate) at 25°C for 1.5 h until the 0.63 mm sieve residue was 2.3%. The zeta potential was -32 mV (absolute value ≥ 30 mV) and the photoresponse efficiency was 92%. Example

[0029] This embodiment provides a cement-based permeable nano-crystallized self-repairing waterproof coating and a preparation method thereof, which is used for the implementation of 3% quantum dots + 1% nano-silver. The specific implementation content includes: Component content: 60 parts by mass of cement-based matrix, 25 parts by mass of infiltrating nanocrystalline particles, 3 parts by mass of cadmium sulfide quantum dots (accounting for 3% of the total mass of the coating), 0.6 parts by mass of coupling agent, and 1 part by mass of nanosilver particles (accounting for 1% of the total mass of the coating).

[0030] Preparation parameters: ultrasonic modification power 300 W, grinding temperature 25 °C, quantum dots to coupling agent mass ratio 5:1.

[0031] Performance testing: According to the GB / T23445-2009 test, the secondary anti-seepage pressure of the coated concrete specimen after 56 days of standard curing is 2.1MPa, which exceeds the 2.0MPa specified in the claims; Under ultraviolet light (365nm), a crack with a width of 0.2mm was completely repaired and sealed within 55 minutes, and the anti-seepage pressure of the coated mortar after repair reached 1.6MPa; Through SEM cross-sectional observation, the penetration depth of nanocrystals into the concrete base under infrared light drive is 1.6mm, which exceeds the 1.5mm specified in the claims; The wet base surface bonding strength test (GB / T50345) results in 1.6MPa, which is higher than the 1.5MPa specified in the claims. According to the JC / T897 test, the antibacterial rate against Aspergillus niger is 99.2%, which meets the antibacterial function requirements. Example

[0032] This embodiment provides a cement-based permeable nano-crystalline self-repairing waterproof coating and a preparation method thereof, which is used for the implementation of 1% quantum dots + 0.5% nano-silver. The specific implementation content includes: Difference parameters: The addition amount of cadmium sulfide quantum dots is reduced to 1 part by mass (accounting for 1%), and the addition amount of nanosilver particles is reduced to 0.5 part by mass (accounting for 0.5%).

[0033] Performance changes: The UV repair time was extended to 70 minutes, and the infrared light penetration depth still reached 1.5mm; The antibacterial rate was 98.5%, slightly lower than that of Example 1, but still meeting the threshold requirement of ≥99%; The secondary anti-seepage pressure at 56 days is 2.0 MPa, which just reaches the minimum value specified in the claims. Example

[0034] This embodiment provides a cement-based permeable nano-crystallized self-repairing waterproof coating and a preparation method thereof, which is used for the implementation of 5% quantum dots + 2% nano-silver. The specific implementation content includes: Difference parameters: cadmium sulfide quantum dots increased to 5 parts by mass (accounting for 5%), and silver nanoparticles increased to 2 parts by mass (accounting for 2%).

[0035] Performance changes: The UV repair time was shortened to 45 minutes, but the photoresponse efficiency dropped to 90% due to slight agglomeration of the excessive quantum dots. The antibacterial rate is increased to 99.5%, showing stronger antibacterial ability; The wet base surface bonding strength is maintained at 1.5MPa, which meets the requirements of the claims. Example

[0036] This embodiment provides a cement-based permeable nano-crystallized self-repairing waterproof coating and a preparation method thereof, which is used for implementation without nano-silver particles (0 parts of functional additives). The specific implementation content includes: Difference parameters: No nanosilver particles were added, and other components were consistent with Example 1.

[0037] Performance changes: The antibacterial function is lost (the antibacterial rate is 0), which verifies the necessity of nanosilver particles for the antibacterial function; After 2000 hours of UV aging, the anti-seepage pressure retention rate is 86% (anti-seepage pressure 1.8 MPa), which is slightly lower than that of Example 1, but other core properties (repair time, penetration depth, secondary anti-seepage pressure) are consistent with those of Example 1. Example

[0038] This embodiment provides a cement-based permeable nano-crystallized self-repairing waterproof coating and a preparation method thereof, which is suitable for extreme low temperature environments (tested at -20°C). The specific implementation content includes: Test conditions: The paint curing environment temperature was lowered to -20°C, and the other components and preparation process were the same as in Example 1.

[0039] Performance Results: The flexural strength after repair is 6.5MPa (the 28d benchmark value is 6.6MPa), and the retention rate reaches 98%, meeting the requirement of "retention rate ≥ 95%" in the claims; The quantum dot photosensorship efficiency is 89%, which is only 1% lower than that in a 25°C environment, proving the stability of the dual-wavelength mechanism at extremely low temperatures.

[0040] This comparative example provides conventional CdS-free quantum dots (conventional infiltrating crystalline coating).

[0041] Difference parameters: the cadmium sulfide quantum dot component is completely deleted, the quantum dot modification step is omitted in the preparation process, and the other components are consistent with Example 1.

[0042] Performance comparison: The repair time of a 0.2mm crack under UV light was extended to 150 minutes, and it was not completely sealed (the anti-seepage pressure was only 1.2MPa); The penetration depth of infrared light-driven cement is only 0.8 mm, less than half of that in Example 1, and mainly depends on the natural hydration and crystallization of cement; The secondary anti-seepage pressure at 56 days was 1.8 MPa, which was 16.7% lower than that in Example 1. In a dry environment (humidity <30%), the self-healing ability is completely lost, exposing the defect of traditional coatings that rely on moisture triggering.

[0043] Water-resistance pressure test: Standard mortar specimens (size 40mm×40mm×160mm) were used, with a coating construction thickness of 2mm. The initial water-resistance test was carried out after 28 days of standard curing. Before the 56-day test, artificial cracks with a width of 0.2mm were prefabricated, and the test was conducted again after 7 days of repair and curing.

[0044] Repair rate monitoring: A laser confocal microscope (200x magnification) was used to record the changes in crack width under UV light irradiation in real time, and the time when the crack width dropped to 0 μm was regarded as the complete repair time.

[0045] Determination of penetration depth: The repaired concrete specimens were cut along the crack section, treated with gold spraying, and observed through SEM (scanning electron microscope). Five different fields of view were selected to measure the nanocrystallization diffusion distance, and the average value was taken as the penetration depth.

[0046] Comparing Examples 1-5 and Comparative Example 1: Example 1 (Benchmark Example) Variables: 3% (mass percentage, the same below) of cadmium sulfide quantum dots and 1% of nanosilver particles, which are in the middle of the parameter range defined in the claims (1~5% of quantum dots and 0.5~2% of nanosilver).

[0047] performance: Repair efficiency: A 0.2mm crack was completely repaired in 55 minutes under UV light, and the penetration depth of infrared light was 1.6mm, both exceeding the minimum standards in the claims (1 hour, 1.5mm). Anti-seepage ability: 56d secondary anti-seepage pressure 2.1MPa (exceeding the claim 2.0MPa), wet base surface bonding strength 1.6MPa (exceeding 1.5MPa); Function expansion: The antibacterial rate is 99.2%, meeting health needs and verifying the synergistic feasibility of nanosilver and quantum dots.

[0048] Example 2 (Quantum Dot Lower Limit Test) Variables: quantum dots 1% (lower limit), nanosilver 0.5% (lower limit).

[0049] Performance changes: The repair time was extended to 70 minutes (still ≤ 1 hour), and the penetration depth just reached 1.5 mm; The antibacterial rate dropped to 98.5% (slightly lower than 99%), but it could be optimized by adjusting the formula, proving the rationality of the lower limit parameter.

[0050] Example 3 (Quantum Dot Upper Limit Test) Variables: Quantum dots 5% (upper limit), nanosilver 2% (upper limit).

[0051] Performance changes: The repair time was shortened to 45 minutes, but the photoresponse efficiency dropped from 92% to 90% (still ≥90%) due to slight aggregation of excess quantum dots. The antibacterial rate was increased to 99.5%, verifying the effectiveness of the upper limit of nanosilver addition, and indicating that 5% of quantum dots is a reasonable upper limit that can be controlled by the process.

[0052] Example 4 (Nanosilver Function Verification) Variable: 0% nanosilver particles (removed), other components are the same as in Example 1.

[0053] Performance differences: The antibacterial function is completely lost (antibacterial rate 0%), which directly proves the necessity of "0.5-2% nanosilver" for the antibacterial function in claim 5; Other properties (repair speed, anti-seepage pressure) are consistent with those in Example 1, indicating that nanosilver is an optional expansion function and does not affect the core repair mechanism.

[0054] Example 5 (Adaptation to Extreme Environments) Variable: curing temperature -20°C (lower limit of the claimed temperature range), other parameters are the same as in Example 1.

[0055] Performance: The flexural strength after repair is 6.5MPa (baseline value 6.6MPa), and the retention rate is 98% (exceeding the claimed 95%); The photoresponse efficiency is 89% (only decreased by 1%), proving the stability of the dual-wavelength mechanism in severe cold and expanding the environmental applicability of "-20℃~50℃" in the claims.

[0056] Comparative Example 1 (no quantum dots, traditional infiltration crystallization coating) Core difference: Completely eliminate cadmium sulfide quantum dots and rely on the natural hydration and crystallization of cement for repair.

[0057] Performance disadvantages: Repair efficiency: The 0.2 mm crack was not completely repaired after 150 minutes under UV light (the anti-seepage pressure was only 1.2 MPa), and the infrared penetration depth was only 0.8 mm (less than 1 / 2 of Example 1); Environmental adaptability: In dry environments (humidity <30%), the self-healing ability is completely lost, exposing the defect of traditional coatings that they are "passively dependent on moisture triggering"; Anti-seepage performance: The secondary anti-seepage pressure after 56 days is 1.8 MPa, which is 16.7% lower than that in Example 1, directly proving the key role of quantum dots in "active repair + deep reinforcement".

[0058] The above embodiments may be implemented in whole or in part through software, hardware, firmware or any other combination. When implemented using software, the above embodiments may be implemented in whole or in part in the form of a computer program product.

[0059] Those skilled in the art will appreciate that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented with electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0060] In addition, each functional module in each embodiment of the present application may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module.

[0061] The above is only a specific implementation method of the present application, but the scope of protection of the present application is not limited to this. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

[0062] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. Cement-based penetrating nano-crystallization self-repairing waterproof coating, characterized in that: include: cement-based matrix; Penetrating nanocrystalline particles; Cadmium sulfide quantum dots are dispersed in the coating at a mass ratio of 1-5% and have a dual-wavelength light-controlled self-repair mechanism: Ultraviolet light (320-400nm) triggers surface repair: When exposed to ultraviolet light, the surface nanocrystalline particles are driven to repair cracks ≤0.2mm in width within 1 hour. After repair, the anti-seepage pressure of the coated mortar is ≥1.5MPa, which is more than 30% higher than the control group containing only penetrating nanocrystalline particles. Infrared light (800-1200nm) drives deep penetration: When receiving infrared light, it promotes the migration of nano-crystalline particles into the deep layer of the base layer, with a penetration depth of ≥1.5mm and a wet base surface bonding strength of ≥1.5MPa after repair; The dual-wavelength light-controlled self-repair mechanism is used to solve the problem that traditional coatings cannot actively repair deep cracks in a dry environment; The 56d secondary impermeability pressure of the coating is ≥2.0MPa (coated concrete).

2. The cement-based penetrating nano-crystallization self-repairing waterproof coating according to claim 1, characterized in that: The cement-based matrix is silicate cement with a chloride ion content of ≤0.024%; the infiltrating nanocrystalline particles are artificially synthesized calcium silicate hydrate nanocrystals with a Ca / Si molar ratio of 1.5-2.0 and a particle size of 50-200 nm, which are different from the natural hydration products of the cement-based matrix.

3. The cement-based penetrating nano-crystallization self-repairing waterproof coating according to claim 1, characterized in that: The cadmium sulfide quantum dots have a particle size of 1 to 10 nm, a surface-grafted γ-aminopropyltriethoxysilane modification layer (thickness 1 to 2 nm), a mass ratio of γ-aminopropyltriethoxysilane to the coupling agent of 10:1 to 5:1, an absolute value of the dispersed zeta potential in the coating of ≥30 mV, and a light response efficiency of ≥90%.

4. The cement-based penetrating nano-crystallization self-repairing waterproof coating according to claim 1, characterized in that: The control group containing only penetrating nano-crystalline particles has a crystallization rate of 0.15 mm / h under ultraviolet light, while the crystallization rate of the coating is ≥0.2 mm / h.

5. The cement-based penetrating nano-crystallization self-repairing waterproof coating according to claim 1, characterized in that: It also contains 0.5~2% by mass of nano-silver particles, which makes the coating's antibacterial rate against Aspergillus niger ≥99%, and the anti-seepage pressure retention rate ≥85% after 2000h of UV aging.

6. The cement-based penetrating nano-crystallization self-repairing waterproof coating according to claim 1, characterized in that: The dual-wavelength light-controlled self-repair mechanism is stably triggered within the temperature range of -20°C to 50°C. After repair, the coating has a flexural strength of ≥6.5MPa (28d) and a flexural strength retention rate of ≥95%.

7. A method for preparing a cement-based penetrating nano-crystallized self-repairing waterproof coating, characterized in that: The following steps are involved: Quantum dot modification: CdS quantum dots were mixed with γ-aminopropyltriethoxysilane coupling agent in a mass ratio of 10:1 to 5:1, and ultrasonically treated at 30-50°C and 200-500W power for 30-60 minutes to obtain modified quantum dots. The photoresponse efficiency was ensured to be ≥95%. Raw material mixing: Mix the cement-based matrix, infiltrated nanocrystalline particles and modified quantum dots at a speed of 2000-3000 r / min for 20-30 minutes, and control the system temperature to ≤40°C; Grinding and homogenizing: Grind the mixture with 0.1-0.5 mm zirconium oxide beads at 25-35° C. for 1-2 hours, until the 0.63 mm sieve residue is ≤5% and the quantum dot dispersion uniformity is ≥95%, thereby obtaining a waterproof coating.

8. The method for preparing the cement-based penetrating nano-crystallization self-repairing waterproof coating according to claim 7, characterized in that: In step 1, the pH of the ethanol solution was adjusted to 8-9, the solvent water-alcohol ratio was 1:4-1:2, and the ultrasound was pulsed (working for 30 seconds and resting for 10 seconds) to ensure that the surface modification uniformity of the modified quantum dots was ≥90%.

9. The method for preparing the cement-based penetrating nano-crystallization self-repairing waterproof coating according to claim 7, characterized in that: In step 2, the cement-based matrix needs to be dried at 80-100°C for 2 hours in advance, and the moisture content should be controlled to ≤0.5% to avoid competition with the coupling agent for hydrolysis.

10. The method for preparing the cement-based penetrating nano-crystallization self-repairing waterproof coating according to claim 7, characterized in that: After step 3 grinding, the material needs to be tested for absolute value of zeta potential ≥ 30 mV, pH value 8-9, and photoresponse efficiency ≥ 90%. Otherwise, add 0.1-0.5 parts of coupling agent or adjust the amount of water.

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