Metal organic framework doped waterproof master batch, cement-based waterproof material and preparation and application of cement-based waterproof material

Abstract

The invention discloses a metal organic framework doped waterproof master batch which comprises MIL-68 (Al), sodium carbonate, sodium silicate and glycine, the waterproof master batch is doped into a cement-based waterproof material, and the waterproof master batch is used for improving the crack resistance and self-repairing efficiency of a concrete structure; the MIL-68 (Al) is prepared by carrying out hydrothermal reaction on reaction raw materials aluminum chloride and terephthalic acid in a reaction solvent N, N-dimethylformamide solution at 120-150 DEG C according to a molar ratio of 1: (1-2). A cement-based waterproof material prepared from the waterproof master batch disclosed by the invention has double advantages of flexible regulation and rigidity enhancement, and has the advantages of strong crack inhibition capability, high MOFs decomposition controllability, good long-term waterproof stability, high microstructure compactness, tight combination with a concrete matrix and self-repairing; the waterproof material is suitable for concrete structure waterproof engineering of easy-to-crack base layers such as building roofs, basements and tunnels.

Description

Technical Field

[0001] This invention relates to the field of modification and optimization technology of cement-based waterproof materials, specifically to a metal-organic framework-doped waterproof masterbatch, a self-healing cement-based waterproof material with the addition of the waterproof masterbatch, and its preparation method and application. Background Technology

[0002] Concrete structures are a core structural form in modern civil engineering and one of the most widely used structural types in fields such as architecture, bridges, tunnels, and water conservancy. The waterproofing performance of concrete structures is crucial for ensuring their long service life and plays a decisive role in maintaining the stability of the building's internal environment and ensuring its normal functionality. To achieve efficient and durable waterproofing, a dual protection system of "concrete body impermeability + additional waterproofing at key locations" needs to be constructed. On the one hand, relying on the density and crack resistance of waterproof concrete, a solid self-waterproofing defense line is built for the structure; on the other hand, for high-risk leakage points such as structural foundations, construction joints, basement facades, roofs, and kitchen and bathroom spaces, targeted additional waterproofing layers are installed using matching waterproofing materials to form a comprehensive, all-encompassing waterproof barrier.

[0003] Currently, widely used cement-based waterproofing materials are mainly divided into two categories: organic and inorganic. Inorganic waterproofing materials are favored in practice because they are chemically compatible with concrete substrates (both belong to the silicate system), have strong adhesion, good durability, and do not require interface treatment agents. However, inorganic materials usually lack flexibility, while an ideal waterproofing system often requires both the durability of rigid protection and the crack resistance of flexible adaptation. Therefore, attempts have been made to achieve complementary advantages through organic-inorganic composites. However, the limited bonding strength between organic materials and cement substrates makes it difficult for the two to form a stable and efficient synergistic waterproofing system, which in turn affects the overall waterproofing effect.

[0004] While existing technologies utilize Na2CO3@SiO2 microcapsules to address issues such as decreased application effectiveness and waste caused by the reaction between highly active masterbatches and cement, thus improving the waterproofing performance of concrete, their high alkalinity and the presence of NaOH, which hinders the preservation of raw materials, limit their practical application. Therefore, addressing the inherent defects of inorganic waterproofing materials, such as high rigidity and poor deformation capacity leading to failure due to cracking of the substrate, and developing waterproofing materials that better meet application requirements remains a key technological focus. Summary of the Invention

[0005] This invention addresses the inherent defects of inorganic waterproofing materials, such as cracking and waterproofing failure due to high rigidity and poor deformation capacity, by providing a metal-organic skeleton-doped waterproofing masterbatch based on MIL-68(Al). When incorporated into cement-based waterproofing materials, it can significantly improve the mechanical and waterproofing properties of concrete structures.

[0006] To achieve the above objectives, the present invention provides a metal-organic framework-doped waterproof masterbatch, comprising MIL-68(Al), sodium carbonate, sodium silicate and glycine. The waterproof masterbatch is incorporated into cement-based waterproof materials to improve the crack resistance and self-healing performance of concrete structures. The MIL-68(Al) is prepared by hydrothermal reaction of aluminum chloride and terephthalic acid in a molar ratio of 1:1~2 in N,N-dimethylformamide solution at 120~150℃.

[0007] With the research and development of new materials technology, metal-organic frameworks (MOFs) have become breakthrough materials due to their high specific surface area, well-organized nanopores, and controllable chemical composition and structure, gradually demonstrating excellent performance in fields such as gas adsorption, catalysis, and sensors. This invention utilizes the chemical properties, size diversity, and controllability of MOFs to modify the structure of cement hydration products. Using MIL-68(Al), a specific MOF material, as the core waterproofing masterbatch for cement-based waterproofing materials, and based on the MIL-68(Al) structure, pre-loaded calcium ions into the pores, thus cleverly achieving physical isolation between the active components and the alkaline environment in the early stages of cement hydration. Under water contact, these components decompose in the cement pore solution, completing an intelligent response mechanism. This marks a crucial step towards intelligent and high-performance waterproofing materials. Specifically, MIF-68 (Al), or MOF-Al material, adsorbs added calcium ions and undergoes partial decomposition under alkaline conditions. The dissolved terephthalic acid coordinates with the calcium ions, preserving the effective calcium ion content while preventing the reaction between calcium ions and added free carbonate ions. When micro-cracks form after the concrete hardens, the chelated calcium ions are released under the action of added water. These chelated ions react with carbonate ions in the concrete and carbon dioxide in the air to form calcium carbonate, sealing the cracks. This creates a targeted repair mode of "immediate repair upon damage," overcoming the limitations of uncontrollable reactions in traditional materials and solving the inherent defects of traditional penetrating crystalline materials (i.e., inorganic materials) that are prone to cracking and waterproofing failure due to high rigidity and poor deformation capacity.

[0008] The role of MIL-68(Al) material in the waterproof masterbatch is to chelate and store added calcium ions, providing calcium ions for the later repair and self-healing of cement cracks. Sodium carbonate is used in the self-healing process to react with calcium ions to form calcium carbonate, effectively filling pores and cracks. Sodium silicate can react with calcium ions to form calcium silicate sol, filling pores and sealing cracks, while providing an alkaline environment for the reaction. The amino and carboxyl groups of glycine are used to assist in the chelation of calcium ions. The four components work together synergistically to significantly improve the intelligent waterproofing and self-healing capabilities.

[0009] As a limitation of the above technical solution, the preparation conditions of MIL-68(Al) are as follows: Aluminum chloride and terephthalic acid were dissolved in N,N-dimethylformamide solution, ultrasonically dispersed, and then transferred to a hydrothermal reactor. The mixture was reacted at 120-150°C for 12-24 h. After the reaction was completed, the mixture was cooled to room temperature and centrifuged to obtain a precipitate. The precipitate was washed and vacuum dried to obtain powdered MIL-68 (Al). Preferably, the volume ratio of N,N-dimethylformamide to water in the N,N-dimethylformamide solution was 3-5:1, and the ultrasonic dispersion time was 30-60 min.

[0010] As a limitation of the above technical solution, the precipitate is washed sequentially with N,N-dimethylformamide and methanol, and then dried under vacuum at 80~100℃ for 6~8h.

[0011] As a limitation of the above technical solution, MIL-68(Al) has a purity of ≥98%, a particle size of 100~500 nm, and a specific surface area of ​​≥1000 m². 2 / g.

[0012] As a limitation of the above technical solution, each 100 parts by weight of cement-based waterproof material includes 5 to 10 parts of MIL-68(Al), 1 to 10 parts of sodium carbonate, 1 to 5 parts of sodium silicate, and 1 to 3 parts of glycine.

[0013] Further refine the preparation conditions and limits on the purity, particle size, and specific surface area of ​​the metal-organic framework MIL-68(Al) material in the waterproof masterbatch, as well as the dosage ratio of the four components in the waterproof masterbatch, to optimize the quality and performance of the waterproof masterbatch.

[0014] Meanwhile, the present invention also provides a cement-based waterproof material, including a base material, a waterproof masterbatch as described above, and additives; preferably, the base material includes silicate cement and quartz sand; and / or, the additives include anhydrous gypsum, volcanic ash, bentonite, water-reducing agent, and hydroxypropyl methylcellulose.

[0015] In cement-based waterproofing materials, the base material is used to promote the compatibility of the waterproofing masterbatch with the concrete substrate; the anhydrous gypsum in the additives provides a calcium source for the self-healing reaction, volcanic ash helps to enhance the impermeability and crack resistance of the concrete structure, bentonite mainly plays a role in physical seepage prevention and water retention thickening, hydroxypropyl cellulose exists as a crack-resistant agent, and the water-reducing agent mainly increases the fluidity of cement and the durability of the concrete structure.

[0016] As a limitation of the above technical solution, each 100 parts by weight of cement-based waterproof material includes 20-40 parts of quartz sand, 5-10 parts of MIL-68(Al), 1-10 parts of sodium carbonate, 1-5 parts of sodium silicate, 1-3 parts of glycine, 1-10 parts of anhydrous gypsum, 1-5 parts of volcanic ash, 1-5 parts of organobentonite, 0.1-1 parts of sodium polycarboxylate superplasticizer, 0.1-1 parts of hydroxypropyl methylcellulose, and silicate cement to make up to 100 parts.

[0017] As a limitation of the above technical solutions, the silicate cement shall be selected with a strength grade of not less than 42.5; and / or, the quartz sand shall be selected with a 50-300 mesh grade; and / or, the volcanic ash shall be selected with a fineness of not less than 800 mesh; and / or, the sodium silicate, anhydrous gypsum, hydroxypropyl cellulose, and glycine shall all be selected with a fineness of not less than 40 mesh; and / or, the organic bentonite shall be selected with a fineness of not less than 400 mesh.

[0018] Further refine the proportions of each component in cement-based waterproofing materials, the strength of the silicate cement used, and the particle size of raw materials such as quartz sand, volcanic ash, sodium silicate, and anhydrous gypsum, to optimize the use and storage performance of waterproofing materials.

[0019] As described above, the preparation method of cement-based waterproof materials involves accurately measuring each component raw material and placing it into a mixer, continuously stirring and mixing it evenly, then sealing and packaging it to prevent external air and moisture from entering, thereby obtaining the cement-based waterproof material product.

[0020] As mentioned above, the application of cement-based waterproofing materials involves adding them to cement mortar or concrete to form a waterproof and self-healing concrete structure. Preferably, the amount of cement-based waterproofing material added is 1 to 5 wt%.

[0021] The preparation of the cement-based waterproof material of this invention only requires simple mixing and sealing packaging. The application is also simple and convenient, and it is suitable for waterproofing projects of various easily cracked concrete structures such as building roofs, basements, and tunnels.

[0022] In summary, the cement-based waterproofing material prepared from the metal-organic framework-doped waterproofing masterbatch of this invention has the following significant beneficial effects: (1) Precise intelligent response and targeted repair capability: Relying on the nanoporous structure and moisture-responsive characteristics of MIL-68 (Al) material, the chelated calcium ions can achieve a precise response of "no release without water and directional release upon contact with water", avoiding the defects of premature reaction of active components in traditional materials. When concrete cracks and water seeps in, the calcium ions chelated in MIL-68 (Al) and glycine are released and react with sodium silicate to form calcium silicate sol, which forms a seal inside the crack; at the same time, it also reacts with some free sodium carbonate and carbon dioxide in the air to form calcium carbonate, forming an external seal. This reaction process can accurately fill cracks, and the repair efficiency is more than 50% higher than that of traditional penetrating crystallizing materials. The self-repair rate of cracks can reach more than 85% (for cracks with a width ≤0.2mm). (2) The various components of cement-based waterproofing materials react with each other and work synergistically, resulting in good protective performance and long-term stable waterproofing performance. Load-bearing MIL-68 (Al) material has good chemical stability inside concrete. Unreacted calcium ions can remain dormant in capillaries for several years. When water seepage occurs, it can trigger a repair reaction, achieving "one-time construction, long-term protection".

[0023] (3) High density: The hydration products generated during the reaction of the loaded MIL-68 (Al) material are mostly carbonate and silicate gels. These gels have good filling properties and can fully fill the cracks, capillaries and other pore structures inside the concrete, significantly reducing the porosity of the concrete and increasing its density. The highly dense structure can effectively prevent the penetration of corrosive media such as moisture and harmful ions, fundamentally improving the waterproof performance and corrosion resistance of the concrete structure and extending its service life. Attached Figure Description

[0024] Figure 1 XRD pattern of MIL-68 (Al) used in Example 1.

[0025] Figure 2 Example 1: Cement-based waterproofing material was added to cement mortar at a dosage of 2wt% for sample crack repair experiments. (a) is an inner view of the sample crack (0.2~0.3mm); (b) is an outer view of the sample crack; (c) and (d) are magnified 1600 times for the corresponding figures (a) and (b), respectively.

[0026] Figure 3 XRD pattern of the components used to repair overflow cracks. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] Unless otherwise specified, the experimental methods described below are conventional methods; the raw materials or test materials used are typical products purchased from the market, unless otherwise specified. In the quantitative experiments of the following examples and comparative examples, three replicate experiments were conducted, and the results were averaged.

[0029] Example The following examples relate to the preparation of metal-organic framework-doped waterproof masterbatch and cement-based waterproof materials.

[0030] Example 1

[0031] The raw material composition (by weight) of 100 parts of cement-based waterproofing material is as follows: 50 parts of silicate cement, 20 parts of quartz sand, 23.5 parts of metal-organic skeleton-doped waterproofing masterbatch, 2 parts of BP-188B organic bentonite, 2 parts of volcanic ash, 0.2 parts of sodium polycarboxylate superplasticizer, 2 parts of anhydrous gypsum, and 0.3 parts of hydroxypropyl methylcellulose; The 23.5 parts of the metal-organic skeleton-doped waterproof masterbatch include 7.5 parts of MIL-68 (Al), 9 parts of sodium carbonate, 5 parts of sodium silicate, and 2 parts of glycine; the strength grade of silicate cement is ≥42.5; the quartz sand is 50~300 mesh graded sand; the fineness of volcanic ash is not less than 800 mesh; the fineness of sodium silicate, anhydrous gypsum, hydroxypropyl methylcellulose, and glycine is not less than 40 mesh; and the fineness of organic bentonite is not less than 400 mesh.

[0032] The preparation of MIL-68 (Al) is carried out as follows: 2.44 g of AlCl3·6H2O and 2.44 g of terephthalic acid were dissolved in 150 mL of N,N-dimethylformamide solution (the volume ratio of N,N-dimethylformamide DMF to water in the solution was 3:1). The solution was ultrasonically dispersed for 40 min, and then refluxed at 135 °C for 18.5 h. After the reaction, the mixture was centrifuged to obtain a white precipitate, which was washed three times with DMF and methanol respectively to remove unreacted raw materials. The precipitate was then vacuum dried at 80–100 °C for 6–8 h to obtain powdered MIL-68(Al). The purity of MIL-68(Al) was determined to be ≥98%, the particle size was 100–500 nm, and the specific surface area was ≥1000 m². 2 / g.

[0033] The preparation conditions of MIL-68 (Al) can be adjusted within a certain range. Specifically, the molar ratio of aluminum chloride to terephthalic acid can be adjusted within the range of 1:1 to 2, the volume ratio of DMF to water in the N,N-dimethylformamide solution can be adjusted within the range of 3 to 5:1, the ultrasonic dispersion time can be adjusted within the range of 30 to 60 min, the reaction temperature can be adjusted within the range of 120 to 150 ℃, and the reaction time can be adjusted within the range of 12 to 24 h.

[0034] The prepared MIL-68 (Al) powder sample was subjected to X-ray diffraction analysis. Figure 1 As can be seen from the XRD pattern, multiple sharp and high-intensity characteristic peaks appeared in the low-angle region (2θ ≈ 5~15°), which is a typical diffraction signal of MIL-68 (Al) and corresponds to the periodic arrangement of its crystal structure; and the main peak near 2θ ≈ 9° has the highest intensity, indicating that the orientation or crystallinity of this crystal plane is good. This shows that the synthesis process successfully prepared the target MOF material, and its crystal structure is complete and its purity is high.

[0035] Preparation of cement-based waterproof materials: The accurately measured raw materials are placed into a mixer and stirred continuously for 10-15 minutes. Then, they are packaged in a container with good airtightness to prevent the entry of outside air and moisture on a packaging machine to obtain cement-based waterproof material products.

[0036] Example 2

[0037] The raw material composition (by weight) of 100 parts of cement-based waterproofing material is as follows: 50 parts of silicate cement, 22 parts of quartz sand, 18 parts of metal-organic skeleton-mixed waterproofing masterbatch, 3 parts of BP-188B organic bentonite, 2 parts of volcanic ash, 0.2 parts of sodium polycarboxylate superplasticizer, 4.5 parts of anhydrous gypsum, and 0.3 parts of hydroxypropyl methylcellulose; The 18 parts of the metal-organic framework-doped waterproof masterbatch include 7 parts of MIL-68 (Al), 5 parts of sodium carbonate, 4 parts of sodium silicate, and 2 parts of glycine; the requirements for each raw material are the same as in Example 1.

[0038] The preparation of metal-organic framework doped waterproof masterbatch and cement-based waterproof material is the same as in Example 1, resulting in cement-based waterproof material products.

[0039] Example 3

[0040] The raw material composition (by weight) of 100 parts of cement-based waterproofing material is as follows: 45 parts of silicate cement, 25 parts of quartz sand, 20 parts of metal-organic skeleton-mixed waterproofing masterbatch, 2 parts of BP-188B organic bentonite, 3 parts of volcanic ash, 0.2 parts of sodium polycarboxylate superplasticizer, 4.5 parts of anhydrous gypsum, and 0.3 parts of hydroxypropyl methylcellulose; The 20 parts of the metal-organic framework-doped waterproof masterbatch include 8 parts of MIL-68 (Al), 7 parts of sodium carbonate, 4 parts of sodium silicate, and 1 part of glycine; the requirements for each raw material are the same as in Example 1.

[0041] The preparation of metal-organic framework doped waterproof masterbatch and cement-based waterproof material is the same as in Example 1, resulting in cement-based waterproof material products.

[0042] Example 4

[0043] The raw material composition (by weight) of 100 parts of cement-based waterproofing material is as follows: 40 parts of silicate cement, 25 parts of quartz sand, 25 parts of metal-organic skeleton-mixed waterproofing masterbatch, 2 parts of BP-188B organic bentonite, 3 parts of volcanic ash, 0.2 parts of sodium polycarboxylate superplasticizer, 4.5 parts of anhydrous gypsum, and 0.3 parts of hydroxypropyl methylcellulose; The 25 parts of the metal-organic framework-doped waterproof masterbatch include 10 parts of MIL-68 (Al), 10 parts of sodium carbonate, 4 parts of sodium silicate, and 1 part of glycine; the requirements for each raw material are the same as in Example 1.

[0044] The preparation of metal-organic framework doped waterproof masterbatch and cement-based waterproof material is the same as in Example 1, resulting in cement-based waterproof material products.

[0045] According to the requirements of GB / T18445—2025 "Cement-based penetrating crystalline waterproofing materials", cement-based waterproofing materials were added to cement mortar at an addition rate of 2wt%. The compressive strength, flexural strength and impermeability of each waterproofing material in Examples 1 to 4 were tested, and the results are shown in Table 1 below.

[0046] Table 1. Compressive strength, flexural strength, and impermeability of the waterproof materials in Examples 1-4

[0047] As shown in Table 1, the compressive strength ratio (28d) of Examples 1-4 is 115-130%, while the standard requirement is ≥100, exceeding the standard by 15%-30%, indicating that the metal-organic skeleton-doped waterproof masterbatch can significantly enhance the compressive strength of concrete; the shrinkage ratio (28d) is 101-105%, while the standard requirement is ≤110%, showing that all examples are far below the upper limit of the standard, indicating that the masterbatch can effectively regulate concrete shrinkage, reduce the risk of cracking, and meet and exceed the standard shrinkage control requirements; based on the principle that a higher compressive strength ratio is better, and a lower shrinkage ratio is better, Example 4 not only meets the requirements but also far exceeds the benchmark level, resulting in a significant performance improvement. The 28-day impermeability ratios of Examples 1-4 ranged from 225% to 237.5%, while the standard requirement is ≥200%, exceeding the standard by 25% to 37.5%. In particular, the impermeability of Example 4 reached 2.375 times that of the benchmark concrete (100%), demonstrating a significant waterproof barrier construction effect. The 28-day secondary impermeability pressure ratio reached 280% to 292.5%, exceeding the standard requirement (≥150%) by 130% to 142.5%, and the secondary impermeability pressure was generally higher than the primary impermeability pressure. This proves that after damage, concrete can achieve self-repair of microcracks through the synergistic effect of adsorption and hydration in the pores of the metal-organic framework, restoring and improving its impermeability. This characteristic is significantly superior to traditional cement-based waterproof materials, providing long-term waterproof protection for concrete structures.

[0048] According to the requirements of GB 18445-2025 "Cement-based penetrating crystalline waterproof materials", cement-based waterproof materials were added to cement mortar at a dosage of 2wt% to prepare cement mortar tanks. After 28 days of standard curing, the tanks were cracked to form cracks of 0.1~0.3mm. Water was continuously injected for 28 days to observe the crack repair effect.

[0049] Figure 2 The images show photographs of samples from Example 1 where the cement-based waterproofing material was added at a dosage of 2 wt% to cement mortar for crack repair experiments. (a) shows the inner side of the crack (0.2~0.3 mm) in the sample; (b) shows the outer side of the crack in the sample. Figure 2 b. As can be seen, when a certain amount of water was added to the sample, no water seeped out from the crack.

[0050] (c) and (d) are corresponding Figure 2 (a) and (b) are magnified images, i.e., microscopic images of the self-healing cracks after using the cement-based material of this invention. Figure 2 As can be seen from c, the crack is filled with white crystals. These white crystals were removed and subjected to XRD analysis, as shown... Figure 3 As shown, the spilled component is mainly CaCO3, which, as a flow component, can quickly repair concrete cracks.

[0051] Comparative Example The following comparative examples are cement-based waterproof materials prepared with different waterproof masterbatches.

[0052] Comparative Example 1 A MOF-doped waterproof masterbatch was prepared using commonly used MOF materials to prepare cement-based waterproof materials.

[0053] The raw material composition (by weight) of 100 parts of cement-based waterproofing material is as follows: 50 parts of silicate cement, 20 parts of quartz sand, 23.5 parts of MOFs-doped waterproofing masterbatch, 2 parts of BP-188B organic bentonite, 2 parts of volcanic ash, 0.2 parts of sodium polycarboxylate superplasticizer, 2 parts of anhydrous gypsum, and 0.3 parts of hydroxypropyl methylcellulose; Among them, 23.5 parts of MOFs-doped waterproof masterbatch include 7.5 parts of ZIF-8, 10 parts of sodium carbonate, 4 parts of sodium silicate, and 2 parts of glycine; the strength grade of silicate cement is ≥42.5; the quartz sand is selected from 50~300 mesh graded sand; the fineness of volcanic ash is not less than 800 mesh; the fineness of sodium silicate, anhydrous gypsum, hydroxypropyl methylcellulose, and glycine is not less than 40 mesh; and the fineness of organic bentonite is not less than 400 mesh.

[0054] ZIF-8 was prepared as follows: Solution A was prepared by mixing 1.484 g Zn(NO3)2·6H2O with 50 mL anhydrous methanol, and solution B was prepared by mixing 3.278 g 2-methylimidazole with 50 mL anhydrous methanol. Solution B was poured into solution A while stirring, and the mixture was stirred for another 60 min at room temperature. After centrifugation and washing with anhydrous methanol, the mixture was dried at 60 °C for 12 h to obtain powdered ZIF-8.

[0055] The preparation procedure for cement-based waterproofing materials is the same as in Example 1.

[0056] Comparative Example 2 Compared to Example 1, MIL-68 (Al) and sodium carbonate are not used in the cement-based waterproofing material.

[0057] The raw material composition (by weight) of the cement-based waterproofing material is as follows: 45 parts silicate cement, 35 parts quartz sand, 3 parts sodium silicate, 1.5 parts glycine, 2 parts BP-188B organic bentonite, 3 parts volcanic ash, 0.2 parts sodium polycarboxylate superplasticizer, 10 parts anhydrous gypsum, and 0.3 parts hydroxypropyl methylcellulose.

[0058] The preparation procedure for cement-based waterproofing materials is the same as in Example 1.

[0059] Comparative Example 3 Compared to Example 1, MIL-68 (A1) is not used in cement-based waterproofing materials.

[0060] The raw material composition (by weight) of the cement-based waterproofing material is as follows: 50 parts silicate cement, 23 parts quartz sand, 9 parts sodium carbonate, 3 parts sodium silicate, 1 part glycine, 3 parts BP-188B organic bentonite, 2 parts volcanic ash, 0.2 parts sodium polycarboxylate superplasticizer, 8.5 parts anhydrous gypsum, and 0.3 parts hydroxypropyl methylcellulose.

[0061] The preparation procedure for cement-based waterproofing materials is the same as in Example 1.

[0062] Comparative Example 4 Compared to Example 1, sodium silicate and glycine are not used in the cement-based waterproofing material.

[0063] The raw material composition (by weight) of the cement-based waterproofing material is as follows: 50 parts silicate cement, 23 parts quartz sand, 7.5 parts MIL-68 (Al), 9 parts sodium carbonate, 3 parts BP-188B organic bentonite, 2 parts volcanic ash, 0.2 parts sodium polycarboxylate superplasticizer, 5 parts anhydrous gypsum, and 0.3 parts hydroxypropyl methylcellulose. The preparation procedures for MIL-68 (Al) and cement-based waterproofing materials are the same as in Example 1.

[0064] Comparative Example 5 Compared to Example 1, conventional sodium citrate is used instead of MIL-68 (Al) and glycine as chelating agents in cement-based waterproofing materials.

[0065] The raw material composition (by weight) of the cement-based waterproofing material is as follows: 50 parts silicate cement, 20 parts quartz sand, 9.5 parts sodium citrate, 9 parts sodium carbonate, 5 parts sodium silicate, 2 parts BP-188B organic bentonite, 2 parts volcanic ash, 0.2 parts sodium polycarboxylate superplasticizer, 2 parts anhydrous gypsum, and 0.3 parts hydroxypropyl methylcellulose. The preparation procedure for cement-based waterproofing materials is the same as in Example 1.

[0066] According to the requirements of GB 18445-2025 "Cement-based penetrating crystalline waterproofing materials", cement-based waterproofing materials were added to concrete at an addition rate of 2wt%. The compressive strength, flexural strength and impermeability of each comparative cement-based waterproofing material were tested. The results are shown in Table 2 below.

[0067] Table 2. Compressive strength, flexural strength and impermeability of waterproof materials in Comparative Examples 1-4

[0068] A comparison of the performance data of the cement-based waterproofing materials in Tables 1 and 2 with those in the comparative examples shows that: (1) In waterproof masterbatch, if the common MOF material ZIF-8 (see Comparative Example 1) is used as raw material, ZIF-8 does not undergo hydrolysis in alkaline solution and cannot form a chelate structure with calcium ions, which leads to a decrease in the impermeability of concrete. (2) In waterproof masterbatch, if MIL-68 (Al) and sodium carbonate (see Comparative Example 2) are not used at the same time, due to the lack of chelated calcium ions, CaCO3 crystals cannot be generated or are generated in small amounts, resulting in a decrease in the impermeability of concrete and a significant reduction in compressive strength. (3) In waterproof masterbatch, if MIL-68 (Al) is not used (see Comparative Example 3), the sodium carbonate component is not protected. Sodium carbonate reacts with the matrix during concrete molding, which leads to a decrease in the impermeability of the concrete. (4) In waterproof masterbatch, if sodium silicate and glycine are not used (see Comparative Example 4), insoluble calcium silicate hydrate will not be formed, and no additional alkaline conditions will be created for the reaction, reducing the degree of decomposition of MIL-68(Al), reducing the amount of calcium ions chelated by terephthalic acid, and causing the concrete to lose its impermeability; at the same time, due to the lack of glycine to assist the chelation reaction of calcium ions, the concrete's impermeability will also decrease slightly. (5) In waterproof masterbatch, if conventional sodium citrate is used to replace MIL-68 (Al) and glycine as chelating agents, the chelating effect is not obvious and the impermeability of concrete decreases.

[0069] This demonstrates that the cement-based waterproofing material formulated with the metal-organic skeleton-doped waterproofing masterbatch of the present invention has significantly improved in terms of compressive strength, impermeability, and self-healing performance. The repair efficiency is more than 50% higher than that of traditional penetrating crystallizing materials, and the self-healing rate of cracks can reach more than 85% (for cracks with a width ≤ 0.2 mm).

[0070] In summary, the cement-based waterproofing material formulated from metal-organic framework doped waterproofing masterbatch of this invention has the dual advantages of flexible control and rigidity enhancement, and also has the advantages of strong crack inhibition ability, high controllability of MOF decomposition, good long-term waterproofing stability, high microstructure density, tight bonding with concrete matrix and self-healing.

[0071] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A metal-organic framework-doped waterproof masterbatch, characterized in that: The waterproof masterbatch, comprising MIL-68(Al), sodium carbonate, sodium silicate, and glycine, is incorporated into cement-based waterproof materials to enhance the crack resistance and self-healing performance of concrete structures. The MIL-68(Al) is prepared by hydrothermal reaction of aluminum chloride and terephthalic acid in a molar ratio of 1:1~2 in N,N-dimethylformamide solution at 120~150℃.

2. The metal-organic framework-doped waterproof masterbatch according to claim 1, characterized in that, The preparation conditions for MIL-68(Al) are as follows: Aluminum chloride and terephthalic acid were dissolved in N,N-dimethylformamide solution, ultrasonically dispersed, and then transferred to a hydrothermal reactor. The mixture was reacted at 120-150°C for 12-24 h. After the reaction was completed, the mixture was cooled to room temperature and centrifuged to obtain a precipitate. The precipitate was washed and vacuum dried to obtain powdered MIL-68 (Al). Preferably, the volume ratio of N,N-dimethylformamide to water in the N,N-dimethylformamide solution was 3-5:1, and the ultrasonic dispersion time was 30-60 min.

3. The metal-organic framework-doped waterproof masterbatch according to claim 2, characterized in that: The precipitate was washed sequentially with N,N-dimethylformamide and methanol, and then dried under vacuum at 80-100℃ for 6-8 hours.

4. The concrete metal-organic skeleton-doped waterproof masterbatch according to claim 2, characterized in that: MIL-68(Al) has a purity of ≥98%, a particle size of 100~500 nm, and a specific surface area of ​​≥1000 m². 2 / g.

5. The metal-organic framework-doped waterproof masterbatch according to claim 1, characterized in that: Each 100 parts by weight of cement-based waterproofing material includes 5-10 parts of MIL-68(Al), 1-10 parts of sodium carbonate, 1-5 parts of sodium silicate, and 1-3 parts of glycine.

6. A cement-based waterproof material, characterized in that: It includes a base material, the waterproof masterbatch as described in any one of claims 1 to 5, and additives; Preferably, the base material includes silicate cement and quartz sand; and / or, the additives include anhydrous gypsum, volcanic ash, bentonite, water-reducing agent, and hydroxypropyl methylcellulose.

7. The cement-based waterproof material according to claim 6, characterized in that: Each 100 parts by weight of cement-based waterproofing material includes 20-40 parts of quartz sand, 5-10 parts of MIL-68(Al), 1-10 parts of sodium carbonate, 1-5 parts of sodium silicate, 1-3 parts of glycine, 1-10 parts of anhydrous gypsum, 1-5 parts of volcanic ash, 1-5 parts of organobentonite, 0.1-1 part of sodium polycarboxylate superplasticizer, 0.1-1 part of hydroxypropyl methylcellulose, and silicate cement to make up to 100 parts.

8. The cement-based waterproof material according to claim 7, characterized in that: The silicate cement shall be of a strength grade of not less than 42.5; and / or, the quartz sand shall be of a 50-300 mesh grade; and / or, the volcanic ash shall be of a fineness of not less than 800 mesh; and / or, the sodium silicate, anhydrous gypsum, hydroxypropyl methylcellulose, and glycine shall all be of a fineness of not less than 40 mesh; and / or, the organobentonite shall be of a fineness of not less than 400 mesh.

9. The method for preparing the cement-based waterproof material according to any one of claims 6 to 8, characterized in that: The accurately measured raw materials are placed into a mixer, continuously stirred and mixed evenly, and then sealed and packaged to obtain a cement-based waterproof material product.

10. The application of the cement-based waterproofing material according to any one of claims 6 to 8, characterized in that: Cement-based waterproofing materials are added to cement mortar or concrete to form a waterproof and self-healing concrete structure; preferably, the amount of cement-based waterproofing material added is 1 to 5 wt%.

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