A stone cultural relic fissure grouting method based on high-pH-resistant microbial mineralization process

Abstract

The application provides a stone cultural relic crack grouting method based on a high-pH-resistant microbial mineralization process. The method comprises small-scale crack and large-scale crack grouting repair; the small-scale crack is treated by grouting with a microbial slurry, and the microbial slurry is prepared from urea, a high-pH-resistant microbial liquid and hydraulic lime; the large-scale crack is sealed and protected by hot melt adhesive and paper adhesive tape before grouting, grouted by microbial mortar prepared from stone powder, hydraulic lime, urea and the high-pH-resistant microbial liquid, and subjected to surface shaping treatment after the grouting and curing are completed; and the high-pH-resistant microbial liquid is obtained by domesticating non-toxic and harmless microorganisms. The application provides a technology and method suitable for cracks of stone cultural relics of multiple scales, can improve the early strength of the hydraulic lime, has the advantages of good salt resistance, green environmental protection, simple operation, low cost, wide application range and the like.

Description

Technical Field

[0001] This invention relates to the field of cultural relic restoration technology, and in particular to a method for grouting cracks in stone cultural relics based on a high-pH-resistant microbial mineralization process. Background Technology

[0002] The main cause of cracks in stone artifacts is weathering, and the erosion of soluble salts is one of the main causes of weathering in stone artifacts. Under the influence of water environments such as capillary water and groundwater, the phase transformation of soluble salts will lead to volume changes, thereby causing damage to stone artifacts. Over time, under the action of external forces, cracks will appear on the surface of stone artifacts.

[0003] Current methods for repairing cracks in stone artifacts typically employ silicate cement, organic polymer materials, or hydraulic lime. However, silicate cement contains a large amount of silicate, which can cause "protective damage" to stone artifacts; organic polymer materials are toxic and increasingly unsuitable for current green and environmentally friendly requirements, and their long-term durability remains questionable; hydraulic lime, as an inorganic material, is widely used, but its low initial strength still needs further improvement.

[0004] Therefore, developing a grouting method for cracks in stone cultural relics is of great significance. Summary of the Invention

[0005] The purpose of this invention is to provide a method for grouting cracks in stone cultural relics based on a high-pH-resistant microbial mineralization process, in order to solve the problems existing in the prior art.

[0006] The technical solution adopted to achieve the purpose of this invention is as follows: a method for grouting fissures in stone cultural relics based on a high-pH-resistant microbial mineralization process, comprising the following steps:

[0007] 1) Crack Identification and Classification. The stone artifacts to be restored are examined to identify and classify cracks into small-scale and large-scale cracks. Small-scale cracks are caused by minute stress concentrations within the material, and their width is less than 5 mm. Large-scale cracks are caused by external factors or material structure problems, and their width is between 5 mm and 10 mm.

[0008] 2) Clean the surface of the stone artifacts to ensure that the cracks are clean and dust-free.

[0009] 3) Screen and acclimate high-pH tolerant microorganisms, and prepare microbial slurry and microbial mortar.

[0010] 4) Repair the cracks. Repair methods include any one or more of the following conditions.

[0011] 4A) Grouting treatment of small-scale cracks is performed using microbial slurry. The microbial slurry comprises the following components: urea, microbial inoculum, and hydraulic lime. The microbial inoculum is selected from those resistant to high pH.

[0012] 4B) Grouting treatment of large-scale cracks is performed using microbial mortar. The microbial mortar comprises the following components: stone powder, hydraulic lime, urea, and microbial inoculum. The microbial inoculum is selected from those resistant to high pH levels.

[0013] 5) After the repair is completed, the repaired part is surface treated to make it flat and consistent with the surrounding stone surface.

[0014] 6) Protect the repaired area. Apply waterproof coating or sunscreen to enhance the weather resistance and anti-aging ability of the repaired area.

[0015] Furthermore, the high-pH-tolerant microorganisms in the microbial solution are obtained by high-pH domestication of non-toxic and harmless strains or extracted from alkaline environments.

[0016] Furthermore, the high-pH-tolerant microorganism is *Pasteurella multocida*. The high-pH acclimation process includes the following steps:

[0017] a) Bacillus pasteurellus with good urease activity was cultured and retained as the mother culture. The pH of the primary culture medium was 9.2-9.3.

[0018] b) Increase the pH of the culture medium to 10.2–10.3, inoculate at a rate of 1%, and culture in a constant temperature shaking incubator for multiple expansion cultures.

[0019] c) After acclimatization and stabilization, continue culturing in a medium with a pH of 11.2–11.3, recording enzyme activity and OD every two hours. 600 .

[0020] d) Repeat steps b) to c) until a microbial culture that maintains good urease activity in an environment with a pH greater than 12 is obtained.

[0021] Furthermore, the alkaline environment is saline-alkali land.

[0022] Furthermore, the stone powder is taken from rock formations similar to the stone artifact to be restored. The rock formations are ground and sieved to obtain stone powder particles of different sizes for later use.

[0023] Furthermore, the formula for the microbial slurry is as follows (by mass-volume ratio): microbial inoculum: urea: hydraulic lime = 50 mL: 3.5 g: 100 g. First, add urea to the inoculum. Once the urea is fully dissolved, add the hydraulic lime and stir until homogeneous to obtain the microbial slurry.

[0024] Furthermore, in step 4A), a syringe is used to inject microbial slurry into the crack, and the crack is repaired by multiple cycles of grouting.

[0025] Furthermore, step 4A) specifically includes the following sub-steps:

[0026] 4A1) Prepare a microbial culture that is resistant to high pH environments. The microbial urease activity is 10±2 U / mL.

[0027] 4A2) Prepare the microbial slurry. First, add urea to the bacterial solution. After the urea is fully dissolved, add hydraulic lime and stir evenly to obtain the microbial slurry.

[0028] 4A3) Microbial slurry is injected into the cracks using a syringe. Multiple cyclic grouting is employed for crack repair.

[0029] Furthermore, the formula for the microbial mortar, by mass-volume ratio, is: stone powder: hydraulic lime: bacterial solution: urea = 100g: 20g: 50mL: 18g. Hydraulic lime is added to the stone powder and thoroughly stirred to obtain mixed aggregates. Simultaneously, urea is fully dissolved in the bacterial solution to obtain a mixed solution. This mixed solution is then added to the mixed aggregates and thoroughly stirred to obtain the microbial repair mortar.

[0030] Furthermore, step 4B) specifically includes the following sub-steps:

[0031] 4B1) Preparation of microbial mortar.

[0032] 4B2) For vertical cracks, use hot melt adhesive or paper tape to seal the cracks and leave a slurry outlet at the bottom of the crack.

[0033] 4B3) Large-scale cracks are grouted using microbial mortar. For transverse cracks, grout is injected sequentially from bottom to top using a syringe to ensure good crack repair results. For vertical cracks, grout is injected from top to bottom using a syringe. When the microbial mortar flows out of the pre-reserved grout outlet at the bottom, the pre-reserved hole is sealed until the microbial mortar no longer penetrates further into the interior.

[0034] 4B4) Seal the grouting port with paper tape, and remove the hot melt adhesive and paper tape after curing for 3 days.

[0035] 4B5) After grouting and curing, surface shaping treatment of the cracks shall be carried out.

[0036] The technical effects of this invention are beyond doubt:

[0037] A. Compared with existing stone cultural relic restoration materials, it has the advantages of being simple to operate, non-toxic and harmless, and environmentally friendly.

[0038] B. It can improve the early strength of hydraulic lime, thereby expanding the application range of hydraulic lime in grouting cracks in stone cultural relics.

[0039] C. Applicable to cracks of different sizes, it employs different construction techniques to treat cracks in stone cultural relics of different sizes, with a wide range of applications and simple operation.

[0040] D. It can maintain good urease activity in high pH environments, which can slow down the damage of soluble salts to repair materials. Attached Figure Description

[0041] Figure 1 Flowchart for the domestication of high pH-tolerant microorganisms;

[0042] Figure 2 This is a schematic diagram of the grouting repair process for small-scale cracks.

[0043] Figure 3 This is a schematic diagram of the grouting repair process for large-scale cracks.

[0044] In the figure: 1. Small-scale crack; 2. Large-scale crack; 3. Microbial slurry; 4. Urea; 5. Microbial inoculum; 6. Hydraulic lime; 7. Hot melt adhesive; 8. Paper tape; 9. Stone powder; 10. Microbial mortar. Detailed Implementation

[0045] The present invention will be further described below with reference to embodiments, but it should not be construed that the scope of the present invention is limited to the following embodiments. Various substitutions and modifications made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention should be included within the scope of protection of the present invention.

[0046] Example 1:

[0047] This embodiment provides a method for grouting fissures in stone cultural relics based on a high-pH-resistant microbial mineralization process, including the following steps:

[0048] 1) Crack Identification and Classification. The stone artifacts to be restored are examined to identify and classify cracks into small-scale cracks (1) and large-scale cracks (2). Small-scale cracks (1) are caused by minute stress concentrations within the material, and their width is less than 5 mm. Large-scale cracks (2) are caused by external factors or material structure problems, and their width is between 5 mm and 10 mm.

[0049] 2) Clean the surface of the stone artifacts to ensure that the cracks are clean and dust-free.

[0050] 3) Screen and acclimate high pH-tolerant microorganisms, and prepare microbial slurry 3 and microbial mortar 4.

[0051] 4) Repair the cracks. Repair methods include any one or more of the following conditions.

[0052] 4A) Small-scale cracks 1 are grouted using microbial slurry 3. The microbial slurry 3 comprises the following components: urea 4, microbial inoculum 5, and hydraulic lime 6. The microbial inoculum 5 is selected from high-pH-tolerant microbial inoculum. The high-pH-tolerant microorganisms in the microbial inoculum 5 are obtained through high-pH acclimation of non-toxic and harmless strains or extracted from an alkaline environment. The formula of the microbial slurry 3, by mass-volume ratio, is: microbial inoculum : urea : hydraulic lime = 50 mL : 3.5 g : 100 g. Urea is first added to the inoculum, and after the urea is fully dissolved, hydraulic lime is added and stirred evenly to obtain microbial slurry 3.

[0053] 4B) Large-scale cracks 2 are grouted using microbial mortar 10. The microbial mortar 10 comprises the following components: stone powder 9, hydraulic lime 6, urea 4, and microbial inoculum 5. The microbial inoculum 5 is a high-pH resistant microbial inoculum. The high-pH resistant microorganisms in the microbial inoculum 5 are obtained through high-pH acclimation of non-toxic and harmless bacteria or extracted from an alkaline environment. The stone powder is taken from a rock mass similar to the stone artifact to be restored. The rock mass is ground and sieved to obtain stone powder particles of different sizes for later use. The formula of microbial mortar 10 is as follows (by mass / volume ratio): stone powder: hydraulic lime: inoculum: urea = 100g: 20g: 50mL: 18g. Hydraulic lime is added to the stone powder and thoroughly stirred to obtain a mixed aggregate. Simultaneously, urea is fully dissolved in the inoculum to obtain a mixed solution. The mixed solution is added to the mixed aggregate and thoroughly stirred to obtain the microbial restoration mortar.

[0054] 5) After the repair is completed, the repaired part is surface treated to make it flat and consistent with the surrounding stone surface.

[0055] 6) Protect the repaired area. Apply waterproof coating and / or sunscreen to enhance the weather resistance and anti-aging ability of the repaired area.

[0056] This embodiment addresses the shortcomings of hydraulic lime in repairing cracks in stone artifacts, namely its low initial strength. It expands the application range of inorganic repair materials, overcoming the limitations of hydraulic lime in effectively repairing large-scale cracks. It also allows for surface shaping of the repaired cracks and offers advantages such as good salt resistance, environmental friendliness, ease of operation, low cost, and wide applicability. While primarily applicable to crack repair in stone artifacts, this embodiment is not limited to stone but can also be used for crack repair in rock formations and brick / stone artifacts.

[0057] Example 2:

[0058] The main content of this embodiment is the same as that of Embodiment 1, wherein, see [link / reference]. Figure 1 The high-pH tolerant microorganism is *Pasteurella multocida*. The high-pH acclimation process includes the following steps:

[0059] a) Bacillus pasteurellus with good urease activity was cultured and retained as the mother culture. The pH of the primary culture medium was 9.2-9.3.

[0060] b) Increase the pH of the culture medium to 10.2–10.3, inoculate at a rate of 1%, and culture in a constant temperature shaking incubator for multiple expansion cultures.

[0061] c) After acclimatization and stabilization, continue culturing in a medium with a pH of 11.2–11.3, recording enzyme activity and OD every two hours. 600 .

[0062] d) Repeat steps b) to c) until a microbial culture that maintains good urease activity in an environment with a pH greater than 12 is obtained, i.e., the urease activity reaches 10±2U / mL.

[0063] Example 3:

[0064] The main content of this embodiment is the same as that of embodiment 1, except that the alkaline environment is saline-alkali land.

[0065] Example 4:

[0066] The main content of this embodiment is the same as any one of embodiments 1 to 3. In step 4A), the microbial slurry 3 is injected into the crack using a syringe, and the crack is repaired by multiple cyclic grouting.

[0067] Example 5:

[0068] The main content of this embodiment is the same as any one of embodiments 1 to 4, wherein, see [link to embodiment 1]. Figure 2 Step 4A) specifically includes the following sub-steps:

[0069] 4A1) Prepare a microbial culture that is resistant to high pH environments. The microbial urease activity is 10±2 U / mL.

[0070] 4A2) Prepare microbial slurry. First, add urea to the bacterial solution. After the urea is fully dissolved, add hydraulic lime and stir evenly to obtain microbial slurry 3.

[0071] 4A3) Microbial slurry is injected into the cracks using a syringe. Multiple cyclic grouting is employed for crack repair.

[0072] Example 6:

[0073] The main content of this embodiment is the same as any one of embodiments 1 to 5, wherein, see [link / reference]. Figure 3Step 4B) specifically includes the following sub-steps:

[0074] 4B1) Prepare microbial mortar 10.

[0075] 4B2) For vertical cracks, use hot melt adhesive 7 or paper tape 8 to seal the cracks, and leave a slurry outlet at the bottom of the crack.

[0076] 4B3) Large-scale cracks 2 were grouted using microbial mortar 10. For transverse cracks, grout was injected sequentially from bottom to top using a syringe to ensure good crack repair results. For vertical cracks, grout was injected from top to bottom using a syringe. When the microbial mortar flowed out of the pre-reserved grout outlet at the bottom, the pre-reserved hole was sealed until the microbial mortar no longer penetrated into the interior.

[0077] 4B4) Seal the grouting port with paper tape 8, and remove the hot melt adhesive and paper tape after curing for 3 days.

[0078] 4B5) After grouting and curing, surface shaping treatment of the cracks shall be carried out.

[0079] Example 7:

[0080] The microbial slurry 3 or microbial mortar 10 described in Examples 1-6 were compared with commercially available silicate cement, organic polymer materials, and hydraulic lime. The test procedure is as follows:

[0081] Step 1: Prepare four different crack grouting repair solutions: Microbial grout 3 has the following ratio: microbial inoculum: urea: hydraulic lime = 50mL: 3.5g: 100g; Microbial mortar 10 has the following ratio: stone powder: hydraulic lime: inoculum: urea = 100g: 20g: 50mL: 18g; Silicate cement has the following ratio: silicate cement: water = 100g: 50ml; Organic polymer material has the following ratio: organic polymer material: water = 100g: 50ml; Hydraulic lime has the following ratio: hydraulic lime: water = 100g: 50ml.

[0082] Step 2: Cure each of the four repair solutions for 24 hours.

[0083] Step 3: Conduct weather resistance and strength tests on the four repair solutions.

[0084] As can be seen, compared with other repair materials on the market, the microbial slurry 3 or microbial mortar 10 described in the embodiments of the present invention have good salt resistance and strength under comprehensive conditions.

Claims

1. A method for crack grouting of stone cultural relics based on high-pH-resistant microbial mineralization process, characterized in that, Includes the following steps: 1) Crack identification and classification: The stone artifacts to be restored are examined, and cracks are identified and classified into small-scale cracks (1) and large-scale cracks (2). 2) Clean the surface of the stone artifacts, ensuring that the cracks are clean and dust-free; 3) Screening and acclimatizing high-pH tolerant microorganisms, and preparing microbial slurry (3) and microbial mortar (10); wherein, the microbial slurry (3) includes the following components: urea (4), microbial inoculum (5) and hydraulic lime (6); the microbial mortar (10) includes the following components: stone powder (9), hydraulic lime (6), urea (4) and microbial inoculum (5); the microbial inoculum (5) in both the microbial slurry (3) and the microbial mortar (10) is selected from high-pH tolerant microbial inoculum; the high-pH tolerant microorganism is Bacillus pasteurellii; the high-pH acclimatization process includes the following steps: a) Bacillus pasteurellii with good urease activity was cultured and retained as the mother culture. The pH of the primary culture medium was 9.2–9.

3. b) Increase the pH of the culture medium to 10.2–10.3, inoculate at a rate of 1%, and culture in a constant temperature shaking incubator for multiple scale-up cultures; c) After acclimatization, the enzyme activity and OD were recorded every two hours after inoculation into the medium with pH 11.2-11.3 600 ; d) Repeat steps b) to c) until a microbial culture that maintains good urease activity in an environment with a pH greater than 12 is obtained; 4) Repair the cracks; the repair methods include any one or more of the following conditions; 4A) Grouting treatment of small-scale cracks (1) is carried out using microbial slurry (3); the crack width of the small-scale cracks (1) is less than 5 mm; 4B) The large-scale cracks (2) are grouted with microbial mortar (10); the crack width of the large-scale cracks (2) is between 5 mm and 10 mm. 5) After the repair is completed, the repaired part is surface treated to make it flat and consistent with the surrounding stone surface; 6) Protect the repaired area.

2. The method for stone heritage crack grouting based on high-pH resistant microbial mineralization process according to claim 1, characterized in that: The microbial culture (5) contains high-pH resistant microorganisms obtained by high-pH domestication of non-toxic and harmless strains or by extraction from an alkaline environment.

3. The method according to claim 2, characterized in that: The alkaline environment is saline-alkali land.

4. The method according to claim 3, characterized in that: The stone powder is taken from a rock mass similar to the stone artifact to be restored; the rock mass is ground and sieved to obtain stone powder particles of different sizes for later use.

5. The method for stone heritage crack grouting based on high-pH resistant microbial mineralization process according to claim 1, characterized in that: The formula of the microbial slurry (3) by mass-volume ratio is: microbial slurry: Urea: hydraulic lime = 50mL: 3.5g: 100g; First, add urea to the bacterial solution. After the urea is fully dissolved, add hydraulic lime and stir evenly to obtain microbial slurry (3).

6. The method for stone heritage crack grouting based on high-pH resistant microbial mineralization process according to claim 1, characterized in that: In step 4A), the microbial slurry (3) is injected into the crack using a syringe, and the crack is repaired by multiple cyclic grouting.

7. The method for stone heritage crack grouting based on high-pH resistant microbial mineralization process according to claim 1, characterized in that, Step 4A) specifically includes the following sub-steps: 4A1) Prepare a microbial culture that is resistant to high pH environment; wherein the microbial urease activity is 10±2U / mL; 4A2) Prepare microbial slurry; first add urea to the bacterial solution, and after the urea is fully dissolved, add hydraulic lime and stir evenly to obtain microbial slurry (3). 4A3) injecting the microbial slurry into the fissure by using a syringe; wherein, the fissure is repaired by using multiple cycles of slurry injection.

8. The method for stone heritage crack grouting based on high-pH resistant microbial mineralization process according to claim 1, characterized in that, The microbial mortar (10) is prepared by mixing 100g of stone powder, 20g of hydraulic lime, 50mL of bacterial solution and 18g of urea, wherein the urea is dissolved in the bacterial solution, and the mixture is added to the stone powder and the hydraulic lime to form the microbial mortar.

9. The method for stone heritage crack grouting based on high-pH resistant microbial mineralization process according to claim 1, characterized in that, Step 4B) specifically comprises the following sub-steps: 4B1) preparing the microbial mortar (10); 4B2) for vertical fissures, the fissure is closed by using hot-melt glue (7) or paper adhesive tape (8), and a slurry outlet is reserved at the bottom of the fissure; 4B3) the microbial mortar (10) is used to grout the large-scale fissure (2); wherein, for horizontal fissures, the microbial mortar is injected from bottom to top by using a syringe; for vertical fissures, the microbial mortar is injected from top to bottom by using a syringe, and when the microbial mortar flows out from the slurry outlet reserved at the bottom, the reserved hole is closed until the microbial mortar no longer penetrates into the interior; 4B4) the slurry outlet is closed by using paper adhesive tape (8), and after 3 days of curing, the hot-melt glue and the paper adhesive tape are removed; 4B5) after the grouting and curing are completed, the surface of the fissure is shaped.

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