Stone soaking pool crack repairing process

Abstract

The invention relates to the field of stone repairing, and particularly discloses a stone soaking pool crack repairing process. A stone soaking pool crack repairing technology comprises the following steps that S1, a to-be-repaired crack of a soaking pool is deeply cleaned, and it is ensured that the to-be-repaired crack is dry and clean; s2, a U-shaped or V-shaped groove is formed in the crack trend, and repairing glue is injected into the groove; s3, after the repairing adhesive is cured, grinding and polishing are conducted, a nanometer protective agent is sprayed to the surface of the repairing adhesive which is ground to be flat, and natural drying is conducted; the repairing adhesive comprises the following raw materials in parts by weight: a nano lithium silicate hybrid polymer, Portland cement, sodium silicate, porous carbon nanofibers, stone powder, glutinous rice glue, silica fume, a defoaming agent and water. According to the repairing adhesive disclosed by the invention, the bonding strength of stone cracks is greatly improved, so that a repaired stone bubble pool has relatively good anti-seepage capability and cold and hot cycle stress cracking resistance.

Description

Technical Field

[0001] This application relates to the field of stone repair technology, and more specifically, it relates to a process for repairing cracks in stone pools. Background Technology

[0002] Natural stone, with its unique texture, elegant feel, and excellent durability, is widely used in the construction of bathing pools and hot spring pools in high-end resort hotels and hot spring baths. Among them, bathing pools carved from a single large piece of stone are highly favored for their natural artistic effect and integrity. However, such large stone bathing pools face two major challenges in actual use and maintenance: (1) During the natural formation process, natural stone may have natural micro-cracks or stratifications inside. In outdoor or semi-outdoor environments, it is subject to long-term diurnal temperature differences, seasonal freeze-thaw cycles, and water penetration and erosion. These inherent defects are very likely to develop into visible macro-cracks; (2) During the carving process, the stone will be subjected to mechanical stress, which may lead to local edge chipping, hidden internal damage, or cracking of the eye texture. In addition, impacts from hard objects during use may also cause damage. These cracks and damages not only seriously affect the aesthetics of the bathing pool, but also lead to leakage, loss of water storage function, and may even cause structural safety hazards due to crack expansion.

[0003] Currently, the main repair techniques for stone include physical filling, surface treatment, and chemical bonding. However, these methods all have significant limitations when applied to the repair of large, pressurized, and water-immersed stone pools. Physical filling involves mixing stone powder, stone chips, and adhesives to create a paste-like putty, which is then used to fill in the damaged areas. It is simple to operate and has a low cost. However, the bonding strength between the filling material and the stone substrate is limited, and it is very easy to fall off under long-term immersion in water and erosion. Moreover, the strength, density, and corrosion resistance of the filler are usually lower than those of the original stone, forming a performance disadvantage.

[0004] Surface treatment methods typically involve grinding, polishing, or applying a coating to the stone surface to cover minor scratches or color differences. While these methods can improve shallow surface damage to some extent, they only address surface issues and are completely ineffective against cracks that affect structural integrity. Furthermore, the coating may peel off, failing to prevent the continued development of internal cracks.

[0005] Chemical bonding typically involves injecting polymer adhesives such as epoxy resin and unsaturated polyester resin into cracks for bonding. For closed cracks, it can provide high bonding strength. However, its coefficient of thermal expansion is different from that of stone. In alternating hot and cold environments, stress is easily generated at the joint, which may lead to secondary cracking or debonding. Moreover, organic adhesives are prone to yellowing and aging under ultraviolet light, water temperature changes, and water immersion, resulting in performance degradation.

[0006] Regarding the aforementioned technologies, existing stone repair techniques generally suffer from insufficient repair strength and durability. Summary of the Invention

[0007] In order to improve the repair strength and durability of stone foam tanks after repair, this application provides a stone foam tank crack repair process.

[0008] Firstly, this application provides a process for repairing cracks in stone foam tanks, employing the following technical solution: A process for repairing cracks in stone bathtubs includes the following steps: S1. Thoroughly clean the cracks in the soaking tub to be repaired, ensuring that the cracks are dry and clean. S2. Cut a U-shaped or V-shaped groove along the crack direction and inject repair adhesive into the groove; S3. After the repair adhesive has cured, grind and polish it, and spray a nano-protective agent onto the smooth repair adhesive surface, then let it dry naturally. The repair adhesive comprises the following raw materials in parts by weight: 100 parts of nano-lithium silicate hybrid polymer, 50-100 parts of silicate cement, 30-50 parts of sodium silicate, 5-10 parts of porous carbon nanofibers, 20-40 parts of stone powder, 5-10 parts of glutinous rice glue, 10-15 parts of silica fume, 0.1-0.5 parts of defoamer, and 150-200 parts of water.

[0009] By adopting the above technical solution, sodium silicate, a water-based penetrating crystallizing material, can penetrate into the cracks of stone in the repair adhesive, reacting chemically with calcium ions in the stone to form hydrated calcium silicate (CSH crystals). It can also react with calcium ions in calcium hydroxide produced during the hydration of silicate cement to form CSH crystals, thus forming a tight bond between the stone and the repair adhesive, sealing the stone cracks, increasing their density, improving impermeability and strength, preventing the formation and spread of cracks, and effectively preventing the penetration of water and corrosive gases. Sodium silicate penetrates into the stone cracks, and in water... Under environmental conditions, the crystals formed by the reaction with calcium ions fill and permeate the cracks. Over the next few weeks, these crystals slowly form a structure that seals the cracks, creating a rigid waterproof layer that can continue to grow. When cracks reappear in the stone, the gel that initially filled the crack slowly solidifies on top, and the gel dehydrates and dries inside. When it comes into contact with moisture again, calcium ions from the silicate cement around the crack dissolve and enter the crack, reacting to form a gel at the crack. This gel then slowly forms a new solidified body that seals the crack, achieving a continuous effect.

[0010] Nano-lithium silicate, hybridized with organic polymers, serves as the core adhesive and functional component of the repair adhesive. It can deeply penetrate stone cracks, forming a lithium silicate-organic polymer network that is both strong and resilient, providing key bonding strength, hydrophobicity, and weather resistance. Silicate cement acts as the structural framework, providing early strength, a highly alkaline environment, and key volume stability. Carbon nanofibers effectively inhibit the initiation and propagation of microcracks, reduce drying shrinkage, and improve flexural strength and impact resistance. Glutinous rice glue, as an organic toughening agent, uses its branched starch molecules to form a flexible organic network that interweaves with the inorganic network, effectively improving the material's toughness and crack resistance while reducing brittleness. Stone powder and silica fume, as performance enhancers, fill micropores. Silica fume reacts with calcium hydroxide produced during cement hydration to generate more gel, increasing density, strength, and impermeability. Stone powder reduces shrinkage, and its color closely matches the stone to be repaired, improving aesthetics. Therefore, the nano-scale lithium silicate in the prepared repair adhesive has strong penetrating power, allowing it to penetrate into the capillary pores of micro-cracks in the stone. It reacts with uncured calcium hydroxide in the stone to generate calcium silicate, filling the pores and forming a sealed and strong adhesive effect. The active silica in the silica fume reacts with the calcium hydroxide produced by cement hydration to generate additional CSH gel, greatly improving the density and later strength. As the glutinous rice glue evaporates and the cement hydration proceeds, its molecular chains intertwine and form a flexible organic film between the inorganic particles. The polymer in the nano-lithium silicate hybrid polymer can form an organic continuous phase film, thus interpenetrating with the inorganic CSH gel produced by silicate cement hydration to form an organic-inorganic interpenetrating network. This significantly improves the density of the repair adhesive after curing and effectively prevents water penetration and erosion. During the curing process of silicate cement, the nano-lithium silicate further reacts with the unreacted free calcium ions that generate calcium silicate hydrate, increasing the crosslinking density of the repair adhesive, thereby resulting in high repair strength, good durability, and strong impermeability.

[0011] Preferably, the mass ratio of the nano-lithium silicate hybrid polymer, silicate cement, and sodium silicate is 100:100:50.

[0012] By adopting the above technical solution, silicate cement serves as the basic framework. Its hydration produces a large amount of calcium hydroxide, which acts as the foundation for the strength of the repair adhesive. This provides a continuous and stable highly alkaline environment for the entire system, thereby activating sodium silicate and nano-lithium silicate to undergo a deep reaction. Sodium silicate, as a powerful activator, reacts rapidly with the calcium hydroxide produced by cement hydration in the highly alkaline environment provided by silicate cement to generate additional CSH gel. The reaction is very fast and can significantly improve early strength. Moreover, the silicate ions it provides can quickly form a gel structure with other cations in the system, such as aluminum ions, rapidly establishing a strength framework. The nano-sized ions in the lithium silicate hybrid polymer, carried by water, can penetrate into the micropores and cracks that silicate cement and sodium silicate cannot reach. In the highly alkaline environment provided by silicate cement, they can react with calcium hydroxide in a volcanic ash reaction to generate more nanoscale CSH gel, greatly filling the micro-cracks, making the repair adhesive more dense, and making the crack and repair adhesive more tightly connected.

[0013] Therefore, a specific ratio of nano-lithium silicate hybrid polymer, silicate cement, and sodium silicate can form an organic-inorganic hybrid network, possessing both the durability of inorganic materials and the flexibility of organic materials. The organic polymer chains can run through the inorganic network, providing micro-toughness and resisting shrinkage and micro-crack formation. Moreover, the lithium silicate reaction products themselves have good hydrophobicity, which can significantly reduce the water absorption rate of the material, providing excellent anti-seepage effect, achieving extreme density, ultra-high early and late strength, excellent durability and anti-aging properties, stable structure, and low shrinkage.

[0014] Preferably, the porous carbon nanofibers undergo the following pretreatment: A suspension was prepared by mixing alkalophilic Bacillus and calcium lactate and dissolving them in deionized water. Porous carbon nanofibers are immersed in a suspending agent, vacuumed and maintained for 15-30 minutes, then depressurized, filtered, and dried. A gelatin solution containing genipin is sprayed onto the surface of the porous carbon nanofibers, kept at 40-45℃ for 2-4 hours, washed, and then freeze-dried.

[0015] By employing the above technical solution, alkalophilic Bacillus and calcium lactate are mixed and stored in porous carbon nanofibers. Vacuuming is used to adsorb microorganisms and calcium lactate, and then gelatin is used to form a brittle protective layer. This protective layer is stable in a dry state, but when cracks form and come into contact with moisture, it quickly dissolves and releases the internal repair agent. When the crack reopens, it tears apart the brittle gelatin layer, directly exposing the microbial spores adsorbed on the surface of the porous carbon nanofibers. Moisture and oxygen from the environment, as well as water seeping from the pool, penetrate along the crack. Simultaneously, the crack also comes into contact with the calcium lactate pre-mixed in the fiber matrix, thus awakening it from its dormant state and causing it to multiply. This leads to the in-situ deposition of calcium carbonate at the crack, thereby filling and bridging the crack and achieving self-repair.

[0016] Preferably, the concentration of Bacillus alkalophilus in the suspension is (3.6-4)×10⁻⁶. 9 pcs / ml; The amount of calcium lactate used is 1.8-2% of the mass of the porous carbon nanofibers; The concentration of the gelatin solution is 3-5%, and the amount of genipin used is 0.5-1% of the gelatin mass.

[0017] By adopting the above technical solution, the above-mentioned amount of bacteria can come into contact with water and newly diffused nutrients and be activated when the crack cracks again after repair. It will begin to metabolize, decompose calcium lactate or other carbon and nitrogen sources, induce calcium carbonate deposition at the crack, and achieve self-healing of the crack.

[0018] Preferably, the porous carbon nanofibers are 30-50 μm in length and are acidified before being impregnated with the suspending agent.

[0019] By adopting the above technical solution, carbon nanofibers, after acid treatment, have carboxyl and hydroxyl functional groups introduced onto their surface. These functional groups can form strong chemical bonds or hydrogen bonds with the CSH gel, a hydration product of silicate cement, as well as the molecular chains of nano-lithium silicate and glutinous rice glue, greatly improving the interfacial bonding force and enhancing its bridging and crack-prevention effect. The length of the carbon nanofibers determines their bridging ability in the repair adhesive. During microcrack propagation, they cross both sides of the crack, preventing further crack expansion through their extremely high tensile strength and interfacial bonding force with the matrix, thus achieving a toughening and strengthening effect. Moreover, carbon nanofibers of this length are easier to disperse when mixed with other raw materials in the repair adhesive, preventing agglomeration and avoiding excessively long fibers that could block the crack entrance during repair, thus preventing the repair adhesive from flowing in.

[0020] Preferably, the concentration of the glutinous rice glue is 2.5-3%, and it is prepared by gelatinizing water-milled glutinous rice flour with a branched starch content of more than 95% at 80-90℃ for 40-60 minutes.

[0021] By adopting the above technical solution, amylopectin is a highly branched polymer. After amylopectin is heated and gelatinized, the chains in the molecules open up like tree branches, resulting in high viscosity, which increases the bonding strength of the repair adhesive. Moreover, the hydroxyl groups at the ends of amylopectin electrostatically attract calcium ions, thereby forming calcium carbonate, which improves the density of the repair adhesive.

[0022] Optionally, the repair adhesive is prepared using the following method: Silicate cement, stone powder and silica fume are mixed evenly to obtain dry material; The nano-lithium silicate hybrid polymer, glutinous rice glue, water and defoamer are mixed evenly to prepare a liquid. The dry and liquid materials are mixed, porous carbon nanofibers are added, and the mixture is stirred evenly to obtain the repair adhesive.

[0023] Preferably, the raw materials of the nano-protective agent include lithium silicate, sodium silicate and nano titanium dioxide in a mass ratio of 7-7.5:2-2.5:0.5-1, and the spraying method of the nano-protective agent is as follows: after mixing lithium silicate and sodium silicate, spray it onto the surface of the repair adhesive after polishing, cure it to form a coating, and then spray nano titanium dioxide onto the coating using a spray gun.

[0024] By adopting the above technical solution, lithium silicate can react with the substrate to generate an inorganic glass protective layer mainly composed of calcium silicate and silica gel. The uniformly dispersed, hard nano-titanium dioxide particles in the inorganic protective layer can act like pinning. When thermal stress causes microcracks to be about to propagate, these nano-titanium dioxide particles force the cracks to change their path and deflect, thereby inhibiting crack initiation and propagation. In addition, after the high hardness and stiffness of titanium dioxide are firmly bonded to lithium silicate gel, it can also significantly improve the overall stiffness and strength of the protective layer, increase wear resistance and impermeability. Furthermore, it can adjust the overall thermal expansion coefficient of the protective layer to a certain extent, making it closer to the stone substrate. During hot and cold cycles, the interfacial stress is reduced, reducing the risk of delamination and cracking.

[0025] Nano-titanium dioxide is applied to the coating by spraying, resulting in a complete and continuous coating surface without cracking or peeling. Water droplets on the coating surface are spherical and slide off more easily, giving the coating better hydrophobicity.

[0026] Preferably, the nano-titanium dioxide comprises nano-titanium dioxide with a particle size of 20 nm and a particle size of 200 nm in a mass ratio of 7:3, and the nano-titanium dioxide is pretreated with 1H,1H,2H,2H0 perfluorodecyltriethoxysilane.

[0027] By adopting the above technical solution, using titanium dioxide particles of different sizes, a coral cluster-like micro-nano structure was constructed on the surface of the protective layer, which improved the surface roughness of the protective layer and made it superhydrophobic. Moreover, the high bonding strength between lithium silicate and stone, and the dense silicate network formed after hydrolysis, improved the durability of the coating to a certain extent, such as mechanical stability, chemical stability and UV aging resistance.

[0028] Preferably, the spraying amount of the nano-protective agent is 100-150 g / m². 2 .

[0029] In summary, this application has the following beneficial effects: 1. This application uses nano-lithium silicate hybrid polymer, sodium silicate, silicate cement, etc. to prepare repair adhesive for repairing stone cracks. Among them, silicate cement can provide a basic skeleton, while sodium silicate provides excellent early strength and stabilizes later strength. The organic hybrid phase of nano-lithium silicate is compounded with glutinous rice glue to give the inorganic rigid skeleton toughness, significantly improving impact resistance and crack resistance. At the same time, its nano-penetration anchoring effect and chemical reaction have excellent bonding strength to stone cracks, thus forming a dense structure with hydrophobicity and long service life. This makes the repaired pool have good impermeability and is not prone to secondary cracks.

[0030] 2. In this application, porous carbon nanofibers are preferably used to load alkalophilic Bacillus and calcium lactate, and then encapsulated with gelatin to form porous carbon nanofibers with self-healing properties. When microcracks occur in the repair adhesive matrix, the microcracks penetrate the porous carbon nanofibers, and water penetrates along the cracks and contacts the gelatin coating layer, thereby exposing substances such as calcium lactate inside, inducing calcium carbonate deposition at the cracks, and completing the self-healing of the repair adhesive.

[0031] 3. This application preferably uses lithium silicate, sodium silicate and nano titanium dioxide as raw materials for nano-protective agents. Lithium silicate and sodium silicate are sprayed first, followed by nano titanium dioxide. This can form a protective layer with high modulus on the repair adhesive and stone surface, which can resist the development of cracks caused by surface micro-defects under stress. This barrier reduces the penetration of moisture and water vapor, prevents moisture from entering the repair adhesive during hot and cold cycles, and effectively prevents scratches and wear, maintaining the flatness and beauty of the repaired surface. Detailed Implementation

[0032] The present application will be further described in detail below with reference to the embodiments.

[0033] Preparation example of nano-lithium silicate hybrid polymer Preparation Example 1: 190g styrene, 140g methyl methacrylate, 140g butyl acrylate, 10g acrylamide, 12g acrylic acid, 20g glycidyl methacrylate, and 35g butyl methacrylate were mixed and stirred evenly to obtain the reactive monomer for later use; 2.5g ammonium persulfate and 40g deionized water were mixed and stirred evenly to obtain the initiator for later use. Mix 485g of deionized water and 10g of lithium silicate, heat in a water bath to 80℃, and add the reactant and initiator dropwise while stirring at 100rpm for 180min. After the addition is complete, keep warm for 60min. After the warming is complete, add 0.5g of ammonium persulfate and 5g of deionized water, and continue to keep warm for 60min to allow the monomer to react fully and reduce the content of residual monomer. Cool down to 45℃, add N,N-dimethylethanolamine to adjust the pH to 9, stir evenly, filter and discharge. Take 820g of the filtered material and mix it evenly with 40g of dipropylene glycol butanol, 135g of deionized water and 2g of wetting agent BYK-346 to obtain nano-lithium silicate hybrid polymer.

[0034] Example of preparation of porous carbon fiber Preparation Example 2: 3g PAN was added to 60mL DMF solution, along with 3g alkali lignin and 6g sodium chloride. The mixture was stirred at 100℃ for 1h to obtain a precursor solution. Electrospinning was performed at room temperature with 30% humidity, a spinning speed of 0.5mL / h, and a voltage of 20kV. The fibers were then cut to obtain porous carbon nanofibers of the required length. The alkali lignin was selected from Hubei GREAT Biomedical, model number GREAT0101. Example

[0035] Example 1: A process for repairing cracks in stone soaking tanks, comprising the following steps: S1. Deeply clean the cracks in the foam tank to be repaired, ensuring that the cracks are dry and clean. The deep cleaning method is as follows: use a polishing machine to grind off the surface protective layer, then use sandpaper to polish it, and then wipe the cracks to remove residue.

[0036] S2. A V-shaped groove is cut along the crack direction. After cleaning, repair adhesive is injected into the groove, with the adhesive filling 5mm above the surrounding surface of the crack. After injection, good ventilation is maintained around the groove to facilitate rapid drying. The raw material quantities for the repair adhesive are shown in Table 1. The nano-lithium silicate hybrid polymer was prepared in Preparation Example 1, the silicate cement was Conch brand P·C42.5, the sodium silicate was selected from Shandong Xinmaoyuan (item number 66), the porous carbon nanofibers were prepared in Preparation Example 2 with a length of 50μm, the stone powder had a particle size of 1250 mesh, the silica fume had an average particle size of 180nm, and a specific surface area of ​​13000m². 2 / kg, the concentration of glutinous rice glue is 3%, which is made by gelatinizing water-milled glutinous rice flour with a branched starch content of more than 95% at 90℃ for 40 minutes. The defoamer is BYK-024. The preparation method of the repair adhesive is as follows: Silicate cement, stone powder and silica fume are mixed evenly to obtain dry material; nano lithium silicate hybrid polymer, glutinous rice glue, water and defoamer are mixed evenly to obtain liquid material; dry material and liquid material are mixed, porous carbon nanofibers are added, and mixed evenly to obtain repair adhesive.

[0037] S3. After the repair adhesive has fully cured, use a polishing machine to grind the repair adhesive that protrudes above the perimeter of the crack, making it flush with the stone surface to form a level surface. Then, spray a nano-protective agent onto the repair adhesive surface at a distance of 25cm above the adhesive, at a rate of 150g / m². 2 The nano-protective agent is selected from Shanghai Silicon-based Industry, model number GS-661.

[0038] Table 1 Example 2: A process for repairing cracks in stone soaking tubs, comprising the following steps: S1. Deeply clean the cracks in the foam tank to be repaired, ensuring that the cracks are dry and clean. The deep cleaning method is as follows: use a polishing machine to grind off the surface protective layer, then use sandpaper to polish it, and then wipe the cracks to remove residue.

[0039] S2. A V-shaped groove is cut along the crack direction. After cleaning, repair adhesive is injected into the groove, extending 3mm above the crack's perimeter. After injection, ensure good ventilation around the groove for rapid drying. The raw material quantities for the repair adhesive are shown in Table 1. The nano-lithium silicate hybrid polymer was prepared in Preparation Example 1. The silicate cement is Conch brand P·C42.5. The sodium silicate is selected from Shandong Xinmaoyuan (item number 66). The porous carbon nanofibers are prepared in Preparation Example 2 and have a length of 30μm. The stone powder has a particle size of 1250 mesh, and the silica fume has an average particle size of 180nm and a specific surface area of ​​13000m². 2 / kg, the concentration of glutinous rice glue is 2.5%, which is made by gelatinizing water-milled glutinous rice flour with a branched starch content of more than 95% at 80℃ for 30 minutes. The defoamer is BYK-024. The preparation method of the repair adhesive is as follows: Silicate cement, stone powder and silica fume are mixed evenly to obtain dry material; nano lithium silicate hybrid polymer, glutinous rice glue, water and defoamer are mixed evenly to obtain liquid material; dry material and liquid material are mixed, porous carbon nanofibers are added, and mixed evenly to obtain repair adhesive.

[0040] S3. After the repair adhesive has fully cured, use a polishing machine to grind the repair adhesive that protrudes above the perimeter of the crack, making it flush with the stone surface to form a level surface. Then, spray a nano-protective agent onto the repair adhesive surface at a rate of 100g / m².2 The nano-protective agent is selected from Shanghai Silicon-based Industry, model number GS-661.

[0041] Examples 3-6: A stone foam pool crack repair process, the difference from Example 1 is that the raw material dosage of the repair adhesive is shown in Table 1.

[0042] Example 7: A stone foam crack repair process, differing from Example 1 in that the porous carbon nanofibers in the repair adhesive undergo the following pretreatment: Alkalophilic Bacillus and calcium lactate were mixed and dissolved in 100g of deionized water to prepare a suspension. The concentration of Alkalophilic Bacillus in the suspension was 3.6 × 10⁻⁶. 9 The concentration of bacteria was 1 / ml, the amount of calcium lactate added was 2% of the mass of porous carbon nanofibers, and the alkalophilic Bacillus was selected from Shanghai Fusheng Industrial Co., Ltd., with the product number FS-J5204. Its activation method was as follows: large-scale culture was carried out in liquid culture medium (1L ultrapure water, 5g peptone, 3g beef extract, 0.42g sodium bicarbonate, 0.53g sodium carbonate, pH 9.7). The bacteria were inoculated into a 150ml Erlenmeyer flask and cultured on a shaker at 30℃ with a shaking frequency of 120r / min for 2h. Porous carbon nanofibers were impregnated in a suspending agent, vacuumed to a negative pressure of 0.06 MPa, held for 30 min, then depressurized, filtered, and dried at 40°C to constant weight. Then, a 5% gelatin solution was sprayed onto the surface, kept at 45°C for 2 h, washed with deionized water, and freeze-dried. The gelatin solution contained genipin, and the amount of genipin was 1% of the mass of the gelatin.

[0043] Example 8: A stone foam pit crack repair process, the difference from Example 1 is that the porous carbon nanofibers in the repair adhesive undergo the following pretreatment: Alkalophilic Bacillus and calcium lactate were mixed and dissolved in 100g of deionized water to prepare a suspension. The concentration of Alkalophilic Bacillus in the suspension was 4×10⁻⁶. 9 The concentration of bacteria was 1.8% of the porous carbon nanofiber mass, and the alkaliphilic Bacillus was selected from Shanghai Fusheng Industrial Co., Ltd., catalog number FS-J5204. Its activation method was as follows: large-scale culture was carried out in liquid culture medium (1L ultrapure water, 5g peptone, 3g beef extract, 0.42g sodium bicarbonate, 0.53g sodium carbonate, pH 9.7). The bacteria were inoculated into a 150ml Erlenmeyer flask and cultured on a shaker at 30℃ with a shaking frequency of 120r / min for 2h. Porous carbon nanofibers were impregnated in a suspending agent, evacuated to a negative pressure of 0.06 MPa, held for 15 minutes, then depressurized, filtered, and dried at 40°C to constant weight. Then, a 3% gelatin solution was sprayed onto the surface, kept at 40°C for 4 hours, washed with deionized water, and freeze-dried. The gelatin solution contained genipin, and the amount of genipin was 0.5% of the gelatin mass.

[0044] Example 9: A stone foam tank crack repair process, the difference from Example 1 is that the porous carbon nanofibers in the repair adhesive undergo the following pretreatment: Alkalophilic Bacillus and calcium lactate were mixed and dissolved in 100g of deionized water to prepare a suspension. The concentration of Alkalophilic Bacillus in the suspension was 3.6 × 10⁻⁶. 9 The concentration of bacteria was 1 / ml, the amount of calcium lactate added was 2% of the mass of porous carbon nanofibers, and the alkalophilic Bacillus was selected from Shanghai Fusheng Industrial Co., Ltd., with the product number FS-J5204. Its activation method was as follows: large-scale culture was carried out in liquid culture medium (1L ultrapure water, 5g peptone, 3g beef extract, 0.42g sodium bicarbonate, 0.53g sodium carbonate, pH 9.7). The bacteria were inoculated into a 150ml Erlenmeyer flask and cultured on a shaker at 30℃ with a shaking frequency of 120r / min for 2h. Porous carbon nanofibers were immersed in concentrated nitric acid for 2 hours, filtered, and repeatedly washed with deionized water until neutral, then vacuum dried. The acid-treated porous carbon nanofibers were then immersed in a suspending agent, vacuumed to a negative pressure of 0.06 MPa, held for 30 minutes, and then depressurized, filtered, and dried at 40°C to constant weight. A 5% gelatin solution was then sprayed onto the surface, kept at 45°C for 2 hours, washed with deionized water, and freeze-dried. The gelatin solution contained genipin, and the amount of genipin was 1% of the gelatin mass.

[0045] Example 10: A stone foam pool crack repair process, which differs from Example 9 in that the raw materials of the nano protective agent include lithium silicate, sodium silicate and nano titanium dioxide in a mass ratio of 7.5:2.5:0.5. The spraying method of the nano protective agent is to mix lithium silicate, sodium silicate and nano titanium dioxide evenly and spray them at a distance of 25cm from the repair adhesive.

[0046] Example 11: A stone foam pool crack repair process, which differs from Example 9 in that the raw materials of the nano-protective agent include lithium silicate, sodium silicate and nano titanium dioxide in a mass ratio of 7.5:2.5:0.5, the nano titanium dioxide has a particle size of 20nm, and the spraying method of the nano-protective agent is as follows: mix lithium silicate and sodium silicate evenly, spray from a distance of 25cm from the repair adhesive, cure for 15min to form a coating, and then spray nano titanium dioxide onto the coating with a spray gun, repeating the spraying 3 times.

[0047] Example 12: A stone foam pool crack repair process, which differs from Example 9 in that the raw materials of the nano-protective agent include lithium silicate, sodium silicate and nano titanium dioxide in a mass ratio of 7:2:1, the particle size of the nano titanium dioxide is 200nm, and the spraying method of the nano-protective agent is as follows: the lithium silicate and sodium silicate are mixed evenly and sprayed at a distance of 25cm from the repair adhesive. After curing for 15 minutes, a coating is formed. The nano titanium dioxide is then sprayed onto the coating with a spray gun and the spraying is repeated 3 times.

[0048] Example 13: A stone soaking pool crack repair process, which differs from Example 9 in that the raw materials of the nano-adsorbent include lithium silicate, sodium silicate and nano titanium dioxide in a mass ratio of 7.5:2.5:0.5. The nano titanium dioxide includes nano titanium dioxide with a particle size of 20nm and a particle size of 200nm in a mass ratio of 7:3. The nano titanium dioxide is modified and pretreated with 1H,1H,2H,2H0 perfluorodecyltriethoxysilane. The specific method is as follows: 600μL of 1H,1H,2H,2H0 perfluorodecyltriethoxysilane is added to 80mL of anhydrous ethanol and stirred for 1h. Then, 2g of nano titanium dioxide particles are added and stirred for 1h. The nano protective agent is sprayed by mixing lithium silicate and sodium silicate evenly and spraying it from a distance of 25cm from the repair adhesive. After curing for 15min to form a coating, the nano titanium dioxide is sprayed onto the coating with a spray gun. The spraying is repeated 3 times.

[0049] Comparative Example Comparative Example 1: A stone foam crack repair process, which differs from Example 1 in that glutinous rice glue is not added to the repair adhesive.

[0050] Comparative Example 2: A stone foam pool crack repair process, which differs from Example 1 in that porous carbon nanofibers are not added to the repair adhesive.

[0051] Comparative Example 3: A stone foam crack repair process, which differs from Example 1 in that an equal amount of lithium silicate is used in the repair adhesive instead of nano-lithium silicate hybrid polymer.

[0052] Comparative Example 4: A stone foam pool crack repair process, which differs from Example 1 in that no nano-protective agent is sprayed.

[0053] Performance testing The following methods were used to test the various properties of the repair adhesives in the embodiments and comparative examples of this application, and the test results are recorded in Table 2.

[0054] 1. Bonding strength: Two standard stone materials (granite, 50mm×50mm×20mm) are bonded together with repair adhesive, with a joint thickness of 3mm, forming a sandwich-type specimen. The specimen is subjected to a pull-out test using a tensile testing machine until failure, and the bonding strength is recorded.

[0055] 2. Resistance to alternating hot and cold cycles: Two standard stone materials (granite, 50mm×50mm×20mm) are bonded together with repair adhesive, with a joint thickness of 3mm. A nano-protective agent is sprayed on to form a sandwich-type specimen. The specimen is placed in an oven at 40℃ for 8 hours, then removed and placed in an environment at 10℃ for 8 hours. This constitutes one cycle. After 50 cycles, the bonding strength is tested. The strength retention rate is calculated as the ratio of the bonding strength after the cycle to the bonding strength before the cycle × 100%. This demonstrates the degree of attenuation after alternating hot and cold cycles. The higher the retention rate, the better the durability.

[0056] 3. Water absorption rate: A straight U-shaped groove is made on the surface of a standard stone (granite, 50mm×50mm×20mm). The length of the U-shaped groove is the same as the length of the stone, and the groove depth is 3mm. Then, the repair adhesive is filled in, and a nano protective agent is sprayed on. It is dried to constant weight and weighed (MO). The side with the U-shaped groove is placed face down, and the repair area is immersed in water to a depth of about 5mm. After 24 hours, it is taken out, the surface moisture is wiped off, and it is weighed (M1). The water absorption rate per unit area is calculated as: W=(M1-M0) / MO×100%.

[0057] 4. Impact toughness and flexural modulus: The performance of the repair adhesive was tested in accordance with JC / T989-2006 "Stone Adhesives for Non-Structural Load-Bearing".

[0058] 5. Crack Repair Width: A straight U-shaped groove is cut into the surface of a standard stone (granite, 50mm×50mm×20mm). The length of the U-shaped groove is the same as the length of the stone, and the groove depth is 3mm. Then, repair adhesive is filled in, and a nano protective agent is sprayed. The repair adhesive area is cut with a water jet, and the width of the cut crack d0 is measured. The initial crack width is designed to be 0.2mm. The width of the cut crack dt is measured at 28 days. The crack repair rate is calculated according to (d0-dt) / d0×100%.

[0059] Table 2 As can be seen from the data in Table 2, the repair adhesives in Examples 1-6 have a high bonding strength to the stone, a high bonding strength retention rate during hot and cold cycles, good durability, low water absorption, strong impermeability, high impact toughness and flexural modulus, and good repair effect.

[0060] Compared with Example 1, Examples 7 and 8 loaded alkalophilic Bacillus and calcium lactate onto porous carbon nanofibers. As shown in Table 2, after the repair adhesive bonded the stone cracks, when cracks appeared at the repair adhesive site, the repair adhesive could complete self-repair, extending the action time of the repair adhesive.

[0061] Compared with Example 1, when loading alkalophilic Bacillus and calcium lactate, the porous carbon nanofibers were first acid-treated. As can be seen from the data in Table 2, the bonding strength of the repair adhesive prepared in Example 9 was increased, the impact toughness and flexural modulus were slightly increased, and the other properties did not change much. This indicates that acid treatment can improve the interfacial bonding force between porous carbon nanofibers and other raw materials and enhance the bridging ability.

[0062] Compared with Example 9, Example 10 uses a nano-protective agent prepared by mixing lithium silicate, sodium silicate and nano titanium dioxide. As shown in Table 2, the water absorption rate of the repaired stone in Example 10 is reduced, and the bonding strength changes little after alternating hot and cold cycles. This indicates that the nano-protective agent prepared by lithium silicate, sodium silicate and nano titanium dioxide can further improve the water-proofing effect of the stone surface.

[0063] Compared with Example 9, Examples 11 and 12 involve spraying lithium silicate and sodium silicate first, followed by spraying nano-titanium dioxide, which further enhances the hydrophobicity of the stone surface.

[0064] Compared with Example 9, in Example 13, not only were lithium silicate and sodium silicate sprayed first, followed by nano titanium dioxide, but the nano silica was also hydrophobically treated. The data in Table 2 show that the water absorption rate of the stone after spraying in Example 13 was further reduced and its impermeability was improved.

[0065] In Comparative Example 1, no glutinous rice glue was added. Compared with Example 1, the repair glue not only had a lower bonding strength, but also a lower bonding strength retention rate, a lower resistance to thermal cycling, and a lower impact toughness and flexural modulus.

[0066] Compared with Example 1, Comparative Example 2 did not add porous carbon nanofibers. The data in Table 2 show that the impact toughness and flexural modulus of the repair adhesive prepared in Comparative Example 2 decreased, and the bonding strength decreased. This indicates that the addition of porous carbon nanofibers can improve the toughness of the repair adhesive and improve the repair effect.

[0067] In Comparative Example 3, lithium silicate was used instead of lithium silicate hybrid polymer. As can be seen, the resulting repair adhesive had reduced impact toughness and flexural modulus, as well as weakened bond strength compared to Example 1.

[0068] Compared with Example 1, Comparative Example 4 did not apply the nano-protective agent, that is, only the repair adhesive was used to fill the cracks in the stone. It can be seen that the water absorption rate of the stone increased and the anti-seepage effect decreased.

[0069] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A process for repairing cracks in stone bathtubs, characterized in that, Includes the following steps: S1. Thoroughly clean the cracks in the soaking tub to be repaired, ensuring that the cracks are dry and clean. S2. Cut a U-shaped or V-shaped groove along the crack direction and inject repair adhesive into the groove; S3. After the repair adhesive has cured, grind and polish it, and spray a nano-protective agent onto the smooth repair adhesive surface, then let it dry naturally. The repair adhesive comprises the following raw materials in parts by weight: 100 parts of nano-lithium silicate hybrid polymer, 50-100 parts of silicate cement, 30-50 parts of sodium silicate, 5-10 parts of porous carbon nanofibers, 20-40 parts of stone powder, 5-10 parts of glutinous rice glue, 10-15 parts of silica fume, 0.1-0.5 parts of defoamer, and 150-200 parts of water.

2. The stone soaking tank crack repair process according to claim 1, characterized in that: The mass ratio of the nano-lithium silicate hybrid polymer, silicate cement, and sodium silicate is 100:100:

50.

3. The stone soaking pool crack repair process according to claim 1, characterized in that: The porous carbon nanofibers undergo the following pretreatment: A suspension was prepared by mixing alkalophilic Bacillus and calcium lactate and dissolving them in deionized water. Porous carbon nanofibers are immersed in a suspending agent, vacuumed and maintained for 15-30 minutes, then depressurized, filtered, and dried. A gelatin solution containing genipin is sprayed onto the surface of the porous carbon nanofibers, kept at 40-45℃ for 2-4 hours, washed, and then freeze-dried.

4. The stone soaking pool crack repair process according to claim 3, characterized in that: The concentration of Bacillus alkalophilus in the suspension is (3.6-4)×10⁻⁶. 9 pcs / ml; The amount of calcium lactate used is 1.8-2% of the mass of the porous carbon nanofibers; The concentration of the gelatin solution is 3-5%, and the amount of genipin used is 0.5-1% of the gelatin mass.

5. The stone soaking pool crack repair process according to claim 3, characterized in that: The porous carbon nanofibers are 30-50 μm in length and are acidified before being impregnated with the suspending agent.

6. The stone soaking pool crack repair process according to claim 1, characterized in that: The concentration of the glutinous rice glue is 2.5-3%, and it is prepared by gelatinizing water-milled glutinous rice flour with a branched starch content of more than 95% at 80-90℃ for 40-60 minutes.

7. The stone soaking pool crack repair process according to claim 1, characterized in that: The repair adhesive is prepared using the following method: Silicate cement, stone powder and silica fume are mixed evenly to obtain dry material; The nano-lithium silicate hybrid polymer, glutinous rice glue, water and defoamer are mixed evenly to prepare a liquid. The dry and liquid materials are mixed, porous carbon nanofibers are added, and the mixture is stirred evenly to obtain the repair adhesive.

8. The stone soaking pool crack repair process according to claim 1, characterized in that: The raw materials of the nano-protective agent include lithium silicate, sodium silicate and nano titanium dioxide in a mass ratio of 7-7.5:2-2.5:0.5-1. The spraying method of the nano-protective agent is as follows: after mixing lithium silicate and sodium silicate, the mixture is sprayed onto the surface of the repair adhesive after polishing, cured to form a coating, and then nano titanium dioxide is sprayed onto the coating using a spray gun.

9. The stone soaking pool crack repair process according to claim 8, characterized in that: The nano-titanium dioxide comprises nano-titanium dioxide with a particle size of 20 nm and a particle size of 200 nm in a mass ratio of 7:3, and the nano-titanium dioxide is pretreated with 1H,1H,2H,2H0 perfluorodecyltriethoxysilane.

10. The stone soaking pool crack repair process according to claim 1, characterized in that: The spraying amount of the nano-protective agent is 100-150 g / m². 2 .

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