Loess cutting slope crack self-repairing material based on natural rubber viscosity change and preparation method of loess cutting slope crack self-repairing material

Abstract

The invention discloses a loess cutting slope crack self-repairing material based on natural rubber viscosity change and a preparation method thereof, and relates to the technical field of repairing material preparation. The self-repairing material comprises natural rubber, a non-aqueous phase dispersant, a cross-linking agent, a cross-linking auxiliary agent, water and a pH regulator, wherein the natural rubber is natural polysaccharide containing cis-ortho-hydroxyl; the cross-linking agent is a boron-containing compound. The invention aims to develop the flowing slurry based on the natural rubber, the slurry can be converted into high-viscosity and high-elasticity gel from low-viscosity fluid within preset time, loess cracks are effectively filled and blocked, the slurry can adapt to tiny deformation of strata, and the self-repairing effect is achieved. The problems that an existing crack repairing material is high in cost and poor in effect are solved.

Description

Technical Field

[0001] This invention relates to the field of repair material preparation technology, specifically to a self-repairing material for loess slope cracks based on the viscosity of natural adhesives and its preparation method. Background Technology

[0002] Loess slope cutting cracks are cracks that form on or within the slope surface due to stress changes caused by artificial slope cutting or natural factors in loess regions. Their formation is closely related to loess properties, cutting methods, hydrogeological conditions, and external forces, posing a serious threat to slope stability and requiring targeted prevention and control measures. Traditional crack repair methods, such as cement grouting, suffer from problems such as material brittleness, incompatibility with loess deformation, and susceptibility to secondary cracking. Chemical grouting materials (such as polyurethane) are expensive and may pollute the environment. Therefore, developing a material that is compatible with the mechanical properties of loess, possesses a certain degree of flexibility, is environmentally friendly and economical, and is easy to construct has significant engineering application value. Summary of the Invention

[0003] To address the aforementioned technical problems, the present invention aims to provide a self-healing material for loess slope cracks based on the natural adhesive transformation and its preparation method, thereby solving the problems of high cost and poor effectiveness of existing crack repair materials.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a self-repairing material for loess slope cracks based on natural gum viscosity is provided, comprising natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, water and pH adjuster; wherein, the natural gum is a natural polysaccharide containing cis-ortho-hydroxyl groups; and the crosslinking agent is a boron-containing compound.

[0005] The beneficial effects of this invention are as follows: This invention aims to develop a fluid slurry based on natural gum, which can transform from a low-viscosity fluid into a high-viscosity, highly elastic gel within a preset time, effectively filling and sealing loess cracks, and adapting to minor geological deformations to achieve a self-healing effect. The core of this invention lies in establishing a reversible cross-linking network through the synergistic effect of natural gum, cross-linking agent, and cross-linking aid, achieving a pH-controllable fluid-gel transition.

[0006] Natural gum forms the main network structure of the material; non-aqueous dispersant improves slurry flowability and slows down the gelation process; crosslinking agent reacts with natural gum to enhance colloid strength and regulate gelation rate; crosslinking aid improves the solubility of natural gum powder, prevents agglomeration, and also slows down the gelation reaction. The above components are added sequentially and thoroughly stirred to obtain a self-healing material for loess slope cracks based on the viscosity of natural gum. This material exhibits excellent flowability and gelation properties, and the gel maintains continuity under certain humidity changes or micro-deformation conditions, making it suitable for the construction and repair of loess slope cracks. For cracks ranging from fine to wide, fine cracks can be directly injected with the adhesive, while wide cracks are sealed with a slurry mixture of the self-healing material and loess (mass ratio of self-healing material to loess greater than 1:3).

[0007] Based on the above technical solution, the present invention can be further improved as follows: Furthermore, the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid and water is 120-130:145-155:280-320:180-220:3000-3500.

[0008] Furthermore, the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid and water is 125:150:300:200:3225.

[0009] Furthermore, the amount of pH adjuster used is to adjust the pH value of the system to 7-9.

[0010] Furthermore, the amount of pH adjuster used is to adjust the pH value of the system to 8.

[0011] Furthermore, the natural gum is at least one of carrageenan, guar gum, guar gum, locust bean gum, and sodium alginate.

[0012] Furthermore, the non-aqueous dispersant is a saturated alkane nonpolar liquid or an oxygen-containing organic liquid.

[0013] Furthermore, the saturated alkane nonpolar liquid is liquid paraffin or white oil.

[0014] Furthermore, the oxygen-containing organic liquid is dioctyl phthalate, vegetable oil, or alcohol ester.

[0015] Furthermore, the vegetable oil is either soybean oil or corn oil.

[0016] Furthermore, the alcohol ester is dioctyl adipate or methyl oleate.

[0017] Furthermore, the crosslinking agent is at least one of sodium tetraborate, boric acid, and organic borate esters.

[0018] Furthermore, the cross-linking agent is a water-soluble small molecule containing multiple hydroxyl groups.

[0019] Furthermore, the crosslinking aid is sorbitol, mannitol, glycerol, or polyethylene glycol.

[0020] Furthermore, the pH adjuster is an organic acid solution.

[0021] Furthermore, the pH adjuster is a citric acid solution.

[0022] Furthermore, the concentration of the citric acid solution is 10 wt%.

[0023] This invention also provides a method for preparing the above-mentioned self-healing material for loess slope cracks based on natural adhesive viscosity, comprising the following steps: (1) Preparation of base slurry: Add crosslinking agent and crosslinking aid to non-aqueous dispersant in sequence, stir evenly, then add natural gum under stirring conditions, continue stirring to form a uniform suspension slurry, then add water, and then stir to obtain base slurry; (2) Add a pH adjuster to the base slurry obtained in step (1) to obtain a mortar, which is a self-repairing material for loess slope cracks based on the natural adhesive.

[0024] In step (1), stir for 10 minutes.

[0025] In step (1), continue stirring for 15 minutes.

[0026] In step (1), stir for 30 minutes.

[0027] The present invention has the following beneficial effects: 1. Natural gum is a natural polysaccharide containing cis-ortho-hydroxyl groups. These cis-ortho-hydroxyl groups (see...) Figure 1 The molecular structure of alginate (where G represents β-D-mannuronic acid unit and M represents α-L-guluronic acid unit) can crosslink with borate and its derivatives or transition metal ions such as zirconium and titanium to form a three-dimensional network structure, thereby causing the slurry to change from a flowing liquid state to an elastic gel state macroscopically.

[0028] 2. The introduction of non-aqueous dispersants primarily serves a physical dispersion function. Natural polysaccharide powders readily form surface agglomerates and fish-eye-like clusters when in direct contact with water, leading to uneven swelling and decreased adhesive properties. Non-aqueous dispersants effectively slow down the contact rate between the natural polysaccharide powder and the aqueous phase by forming a hydrophobic coating layer on the surface, preventing the formation of fish-eye-like clusters. Furthermore, the appropriate introduction of non-aqueous dispersants can reduce the overall viscosity of the system, improve flowability and pumpability, making it suitable for injection casting applications.

[0029] 3. Crosslinking agents in the system mainly construct a three-dimensional network structure by forming reversible borate diester bonds (-BOC-) with adjacent hydroxyl groups (-OH) on the natural gum molecular chain. The crosslinking density determines the viscoelasticity of the system and may affect its reversibility and strain recovery ability. Borate crosslinking agents dissociate into tetrahydroxyborate ions [B(OH)4] under alkaline conditions. - [ ] can react with polyhydroxy polymers, forming a non-flowing gel within a certain time; while organoboronate crosslinking agents have a slower hydrolysis rate in aqueous solution, enabling sustained-release crosslinking, which helps to control the gelation rate and workable time. By changing the type and amount of borate crosslinking agent, a dynamic balance can be achieved between initial flow and later thickening, thus balancing workability and structural stability.

[0030] 4. Crosslinking aids, on the one hand, can form weak hydrogen-bonded complexes with natural rubber powder, temporarily inhibiting the rapid swelling of the natural rubber powder surface, preventing local agglomeration, and ensuring a uniform and controllable dissolution process; on the other hand, after subsequent heating or pH adjustment, they can participate in borate esterification reactions, acting as migratory crosslinking bridges, forming a flexible secondary crosslinking network within the system, improving the toughness and reversibility of the gel; in addition, crosslinking aids can also change the polarity and viscosity of the solvent environment to a certain extent, thereby affecting the formation constant and bond energy of borate esters. For example, polyol aids can stabilize the BO bond structure, slow down the dissociation rate of the crosslinking network during humidification, and improve the structural retention of the material during wet-dry cycles. By adjusting the type and concentration of crosslinking aids, different systems from rapid gelation to delayed gelation can be designed to meet the sealing requirements under different crack widths and seepage rates.

[0031] 5. The synergistic effect of crosslinking agents and crosslinking auxiliaries is key to achieving the controllable viscosity change of this material. The crosslinking agent provides the structural basis for reversible chemical bonds, while the crosslinking auxiliaries, by adjusting the dissolution rate and network flexibility, construct a multi-level crosslinking system that combines fluidity, stability, and responsiveness. The ratio of the two, the reaction sequence, and the pH control parameters are the core process factors determining the final performance of the material.

[0032] 6. The crosslinking reaction of borates is highly sensitive to pH. Under alkaline conditions, borates can generate tetrahydroxyborate, which coordinates with the cis-ortho-hydroxyl groups in natural gum molecules to form borate ester bonds. Under neutral conditions (pH around 7), the gelation reaction is rapid but the structure is relatively unstable; under weakly alkaline conditions (pH 8-9), the reaction rate is moderate and can be controlled by fine-tuning the pH. Under acidic conditions (pH < 7), the reaction is further slowed down. pH adjusters (such as citric acid or other organic acids) are used to precisely control the pH of the system, from strong alkalinity (pH > 10.5, promoting dissolution) to weak alkalinity / neutrality (pH 7-9, triggering crosslinking), thereby achieving controllability of the gelation time.

[0033] 7. The mechanism of natural rubber becoming sticky (see...) Figure 2 Natural gum contains a polysaccharide structure with cis-ortho-hydroxyl groups, which react with [B(OH)4] under specific pH conditions. - A cross-linking reaction occurs, transforming the system from a low-viscosity fluid into a high-viscosity gel. Under different pH conditions, different types or amounts of cross-linking auxiliaries and cross-linking agents will affect the gelation time of the system, forming a set of variable-viscosity natural rubber systems with customizable gelation times. The system of this invention is strongly alkali-promoted and weakly alkali-crosslinked. In a strongly alkaline environment with pH > 10.5, the natural rubber powder is fully hydrated without cross-linking, and the system has good fluidity; when the pH is adjusted to the range of 8-9, borate ions [B(OH)4]... - The system rapidly undergoes reversible crosslinking with polyhydroxy polymers, transforming from a low-viscosity liquid to a high-viscosity gel. When the pH further decreases to approximately 7, although the viscosity increases rapidly, the crosslinked structure remains relatively unstable due to the partial conversion of borate to H3BO3, leading to localized gelation. Benefiting from this viscosity-changing mechanism, the system can be transformed from a fluid (energy dissipation modulus G'' > storage modulus G') to an elastic gel (G' > G'') by adjusting the pH and crosslinking agent content. The gelation time can be controlled within 5 minutes to 1 hour. Therefore, this system possesses a wide range of viscoelasticity regulation capabilities, making it suitable for various grouting processes. For example, fine cracks can be directly grouted, while wider cracks can be sealed using a mixture of natural adhesive and loess.

[0034] In summary, the effects of this invention are as follows: 1. Through the pH triggering mode of "strong alkali promotes dissolution - weak alkali crosslinking", the controllable transformation from low viscosity pumpable to elastic gel is achieved. The gelation time is adjustable in the range of 5-60 minutes, which meets the requirements of grouting construction under different crack sizes and seepage conditions.

[0035] 2. The non-aqueous dispersant forms a hydrophobic coating on the powder surface, avoiding fish-eye agglomeration, significantly improving dissolution uniformity and pumpability, and providing process assurance for long-distance grouting on site.

[0036] 3. In addition to improving solubility, polyhydroxy crosslinking aids can form reversible borate ester bonds with borate ions, acting as migratory bridging chains to construct flexible secondary networks. This structure can undergo reversible dissociation and recombination under external forces, effectively dispersing stress and buffering deformation. Attached Figure Description

[0037] Figure 1 It is a cis-ortho-hydroxyl group; Figure 2 This is a schematic diagram of the crosslinking mechanism; Figure 3 Here are the pH-time-viscosity line graphs for the self-healing materials of Examples 1-3 and Comparative Example 1; Figure 4Example 2: Flowability test of self-healing materials; Figure 5 Rheological curves of the system before and after gelation.

[0038] Figure 6 Gel formation time and viscosity data under different crosslinking agent contents; Figure 7 Data on gelation time and viscosity under different crosslinking agent contents. Detailed Implementation

[0039] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer should be followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0040] Example 1: A self-healing material for loess slope cracks based on the viscosity of natural gum includes natural gum (carrageenan), a non-aqueous dispersant (liquid paraffin), a crosslinking agent (sodium tetraborate), a crosslinking aid (sorbitol), water, and a pH adjuster (citric acid solution); wherein the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, and water is 125:150:300:200:3225.

[0041] A method for preparing a self-healing material for loess slope cracks based on the viscosity transformation of natural adhesives includes the following steps: (1) Preparation of base slurry: Add crosslinking agent and crosslinking aid to non-aqueous dispersant in sequence, stir for 10 min to form a uniform pre-dispersion liquid, then add natural rubber powder under stirring conditions, continue stirring for 15 min to form a uniform suspension slurry, ensure that the natural rubber powder does not have obvious agglomeration, then slowly add water, and then stir at high speed for 30 min to obtain base slurry; (2) In the base slurry obtained in step (1), add citric acid solution (concentration of 10wt%) as pH adjuster, and at the same time use an online pH meter to monitor and adjust the pH value of the base slurry to 7 to obtain the slurry, which is a self-repairing material for loess slope cracks based on natural adhesive. In a constant temperature environment of 25°C, the slurry gelling time is 5min.

[0042] Example 2: A self-healing material for loess slope cracks based on the viscosity of natural gum includes natural gum (carrageenan), a non-aqueous dispersant (liquid paraffin), a crosslinking agent (sodium tetraborate), a crosslinking aid (sorbitol), water, and a pH adjuster (citric acid solution); wherein the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, and water is 125:150:300:200:3225.

[0043] A method for preparing a self-healing material for loess slope cracks based on the viscosity transformation of natural adhesives includes the following steps: (1) Preparation of base slurry: Add crosslinking agent and crosslinking aid to non-aqueous dispersant in sequence, stir for 10 min to form a uniform pre-dispersion liquid, then add natural rubber powder under stirring conditions, continue stirring for 15 min to form a uniform suspension slurry, ensure that the natural rubber powder does not have obvious agglomeration, then slowly add water, and then stir at high speed for 30 min to obtain base slurry; (2) In the base slurry obtained in step (1), add citric acid solution (concentration of 10wt%) as pH adjuster, and at the same time use an online pH meter to monitor and adjust the pH value of the base slurry to 9 to obtain the slurry, which is a self-repairing material for loess slope cracks based on natural adhesive. In a constant temperature environment of 25°C, the slurry gelling time is 30min.

[0044] Example 3: A self-healing material for loess slope cracks based on the viscosity of natural gum includes natural gum (carrageenan), a non-aqueous dispersant (liquid paraffin), a crosslinking agent (sodium tetraborate), a crosslinking aid (sorbitol), water, and a pH adjuster (citric acid solution); wherein the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, and water is 125:150:300:200:3225.

[0045] A method for preparing a self-healing material for loess slope cracks based on the viscosity transformation of natural adhesives includes the following steps: (1) Preparation of base slurry: Add crosslinking agent and crosslinking aid to non-aqueous dispersant in sequence, stir for 10 min to form a uniform pre-dispersion liquid, then add natural rubber powder under stirring conditions, continue stirring for 15 min to form a uniform suspension slurry, ensure that the natural rubber powder does not have obvious agglomeration, then slowly add water, and then stir at high speed for 30 min to obtain base slurry; (2) In the base slurry obtained in step (1), add citric acid solution (concentration of 10wt%) as pH adjuster, and at the same time use an online pH meter to monitor and adjust the pH value of the base slurry to 8 to obtain the slurry, which is a self-repairing material for loess slope cracks based on natural adhesive. In a constant temperature environment of 25°C, the slurry gelling time is 20min.

[0046] Comparative Example 1: A self-healing material for loess slope cracks based on the viscosity of natural gum includes natural gum (carrageenan), non-aqueous dispersant (liquid paraffin), crosslinking agent (sodium tetraborate), crosslinking aid (sorbitol), and water; wherein the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, and water is 125:150:300:200:3225.

[0047] A method for preparing a self-healing material for loess slope cracks based on the viscosity transformation of natural adhesives includes the following steps: As in step (1) of Example 1, the resulting base slurry remained fluid after standing for 24 hours and did not undergo gelation.

[0048] Comparative Example 2: A self-healing material for loess slope cracks based on the viscosity of natural gum includes natural gum (carrageenan), a non-aqueous dispersant (liquid paraffin), a crosslinking agent (sodium tetraborate), water, and a pH adjuster (citric acid solution); wherein the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, and water is 125:150:300:3225.

[0049] A method for preparing a self-healing material for loess slope cracks based on the viscosity transformation of natural adhesives includes the following steps: Similar to Example 1, the resulting base slurry contained a large number of undispersed adhesive powder agglomerates, i.e., fish eyes, which significantly affected the performance of the base slurry system.

[0050] Comparative Example 3: A self-healing material for loess slope cracks based on the viscosity of natural gum includes natural gum (carrageenan), a non-aqueous dispersant (liquid paraffin), a crosslinking agent (sodium tetraborate), a crosslinking aid (sorbitol), water, and a pH adjuster (citric acid solution); wherein the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, and water is 125:150:300:200:3225.

[0051] A method for preparing a self-healing material for loess slope cracks based on the viscosity transformation of natural adhesives includes the following steps: In step (2), the pH value of the base slurry is adjusted to 10, and the rest is the same as in Example 1.

[0052] Comparative Examples 4-6: A self-healing material for loess slope cracks based on the viscosity of natural gum includes natural gum (carrageenan), a non-aqueous dispersant (liquid paraffin), a crosslinking agent (sodium tetraborate), a crosslinking aid (sorbitol), water, and a pH adjuster (citric acid solution); wherein the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, and water is 125:150:4:200:3225, and the content of crosslinking agent is 0.1wt%.

[0053] A method for preparing a self-healing material for loess slope cracks based on the viscosity transformation of natural adhesives includes the following steps: In step (2), the pH values ​​of the base slurry are adjusted to 7, 8, and 9 respectively, and the rest is the same as in Example 1.

[0054] Comparative Examples 7-9: A self-healing material for loess slope cracks based on the viscosity of natural gum includes natural gum (carrageenan), a non-aqueous dispersant (liquid paraffin), a crosslinking agent (sodium tetraborate), a crosslinking aid (sorbitol), water, and a pH adjuster (citric acid solution); wherein the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, and water is 125:150:20:200:3225, and the crosslinking agent content is 0.5wt%.

[0055] A method for preparing a self-healing material for loess slope cracks based on the viscosity transformation of natural adhesives includes the following steps: In step (2), the pH values ​​of the base slurry are adjusted to 7, 8, and 9 respectively, and the rest is the same as in Example 1.

[0056] Comparative Examples 10-12: A self-healing material for loess slope cracks based on the viscosity of natural gum includes natural gum (carrageenan), a non-aqueous dispersant (liquid paraffin), a crosslinking agent (sodium tetraborate), a crosslinking aid (sorbitol), water, and a pH adjuster (citric acid solution); wherein the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, and water is 125:150:40:200:3225, and the crosslinking agent content is 1wt%.

[0057] A method for preparing a self-healing material for loess slope cracks based on the viscosity transformation of natural adhesives includes the following steps: In step (2), the pH values ​​of the base slurry are adjusted to 7, 8, and 9 respectively, and the rest is the same as in Example 1.

[0058] Comparative Examples 13-15: A self-healing material for loess slope cracks based on the viscosity of natural gum includes natural gum (carrageenan), a non-aqueous dispersant (liquid paraffin), a crosslinking agent (sodium tetraborate), a crosslinking aid (sorbitol), water, and a pH adjuster (citric acid solution); wherein the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, and water is 125:150:80:200:3225, and the crosslinking agent content is 2wt%.

[0059] A method for preparing a self-healing material for loess slope cracks based on the viscosity transformation of natural adhesives includes the following steps: In step (2), the pH values ​​of the base slurry are adjusted to 7, 8, and 9 respectively, and the rest is the same as in Example 1.

[0060] Comparative Examples 16-18: A self-healing material for loess slope cracks based on the viscosity of natural gum includes natural gum (carrageenan), a non-aqueous dispersant (liquid paraffin), a crosslinking agent (sodium tetraborate), a crosslinking aid (sorbitol), water, and a pH adjuster (citric acid solution); wherein the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, and water is 125:150:200:200:3225, and the crosslinking agent content is 5wt%.

[0061] A method for preparing a self-healing material for loess slope cracks based on the viscosity transformation of natural adhesives includes the following steps: In step (2), the pH values ​​of the base slurry are adjusted to 7, 8, and 9 respectively, and the rest is the same as in Example 1.

[0062] Comparative Examples 19-21: A self-healing material for loess slope cracks based on the viscosity of natural gum includes natural gum (carrageenan), a non-aqueous dispersant (liquid paraffin), a crosslinking agent (sodium tetraborate), a crosslinking aid (sorbitol), water, and a pH adjuster (citric acid solution); wherein the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, and water is 125:150:400:200:3225, and the crosslinking agent content is 10wt%.

[0063] A method for preparing a self-healing material for loess slope cracks based on the viscosity transformation of natural adhesives includes the following steps: In step (2), the pH values ​​of the base slurry are adjusted to 7, 8, and 9 respectively, and the rest is the same as in Example 1.

[0064] Comparative Examples 22-24: A self-healing material for loess slope cracks based on the viscosity improvement of natural gum includes natural gum (carrageenan), non-aqueous dispersant (liquid paraffin), crosslinking agent (sodium tetraborate), crosslinking aid (sorbitol), water, and pH adjuster (citric acid solution); wherein the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, and water is 125:150:300:40:3225, and the content of crosslinking agent is 1wt%.

[0065] A method for preparing a self-healing material for loess slope cracks based on the viscosity transformation of natural adhesives includes the following steps: In step (2), the pH values ​​of the base slurry are adjusted to 7, 8, and 9 respectively, and the rest is the same as in Example 1.

[0066] Comparative Examples 25-27: A self-healing material for loess slope cracks based on the viscosity improvement of natural gum includes natural gum (carrageenan), non-aqueous dispersant (liquid paraffin), crosslinking agent (sodium tetraborate), crosslinking aid (sorbitol), water, and pH adjuster (citric acid solution); wherein the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, and water is 125:150:300:80:3225, and the content of crosslinking agent is 2wt%.

[0067] A method for preparing a self-healing material for loess slope cracks based on the viscosity transformation of natural adhesives includes the following steps: In step (2), the pH values ​​of the base slurry are adjusted to 7, 8, and 9 respectively, and the rest is the same as in Example 1.

[0068] Comparative Examples 28-30: A self-healing material for loess slope cracks based on the viscosity improvement of natural gum includes natural gum (carrageenan), non-aqueous dispersant (liquid paraffin), crosslinking agent (sodium tetraborate), crosslinking aid (sorbitol), water, and pH adjuster (citric acid solution); wherein the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, and water is 125:150:300:300:3225, and the content of crosslinking agent is 7.5wt%.

[0069] A method for preparing a self-healing material for loess slope cracks based on the viscosity transformation of natural adhesives includes the following steps: In step (2), the pH values ​​of the base slurry are adjusted to 7, 8, and 9 respectively, and the rest is the same as in Example 1.

[0070] Comparative Examples 31-33: A self-healing material for loess slope cracks based on the viscosity improvement of natural gum includes natural gum (carrageenan), non-aqueous dispersant (liquid paraffin), crosslinking agent (sodium tetraborate), crosslinking aid (sorbitol), water, and pH adjuster (citric acid solution); wherein the mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, and water is 125:150:300:400:3225, and the content of crosslinking agent is 10wt%.

[0071] A method for preparing a self-healing material for loess slope cracks based on the viscosity transformation of natural adhesives includes the following steps: In step (2), the pH values ​​of the base slurry are adjusted to 7, 8, and 9 respectively, and the rest is the same as in Example 1.

[0072] Test case I. The self-healing materials prepared in Examples 1-3 and Comparative Example 3 were subjected to time and viscosity tests. The specific testing method was as follows: a Brookfield DV-III rotational viscometer was used, and measurements were taken at a constant temperature of 25°C. A suitable rotor and rotation speed were selected, and the time was started from the moment the sample was thoroughly mixed and the pH adjuster was added. The apparent viscosity value of the system was recorded periodically until the viscosity reached the preset time. The results are shown below. Figure 3 ( Figure 3 In the figure, the dashed line represents the reference threshold for pumpable viscosity of 10000 mPa·s.

[0073] Depend on Figure 3 It can be seen that the concentration of natural rubber is about 3.1%, and the fluidity of the system is highly correlated with pH. When the pH is 7, the gelation is rapid, and the viscosity increases sharply within 5 minutes; when the pH is between 8 and 9, the gelation rate slows down, but the viscosity continues to rise after 5 minutes.

[0074] 2. The self-healing material prepared in Example 3 was subjected to flowability testing. The specific testing method was as follows: the self-healing material was coated onto a smooth glass surface, then placed vertically to allow it to flow, and observations were made at different times. The results are shown below. Figure 4 .

[0075] Depend on Figure 4 It can be seen that the material has good flowability and spreadability in the initial stage (1 minute); as time goes on, its flowability gradually decreases, and it begins to thicken significantly and reduce flow within 5-8 minutes; by 10 minutes, the material has basically lost its flowability and adheres stably to the vertical glass surface with a fixed shape. This indicates that the material has controllable flowability and good thixotropy, providing a suitable operating window for construction.

[0076] III. The rheological properties of the self-healing material prepared in Example 1 were tested. The specific testing method was as follows: Samples from Example 1 were taken before gelation (freshly mixed) and after gelation (after standing for 30 minutes), and rheological tests were performed on a plate using a rotational rheometer at 25°C. For the sample before gelation (low strength), strain scanning was performed; for the sample after gelation (high strength), stress scanning was performed. All tests were conducted at a constant angular frequency (e.g., 10 rad / s), and the changes in storage modulus (G') and loss modulus (G'') were recorded. The results are shown below. Figure 5 .

[0077] Depend on Figure 5 It can be seen that for materials before gelation ( Figure 5 (Middle left figure) Throughout the entire test strain range, its loss modulus G'' is consistently significantly higher than its storage modulus G', with G'' values ​​around 100 Pa and G' values ​​below 20 Pa. This indicates that the material exhibits typical liquid behavior at this point, with viscosity dominating. For the gelled material ( Figure 5(See the right-middle figure), its energy storage modulus (G') increases significantly to approximately 10. 5 Pa, which is much higher than the loss modulus (G'', approximately 10). 4 The values ​​of G' and G'' are approximately equal in strength (Pa), meaning G' >> G'', with G' being nearly an order of magnitude higher than G''. This indicates that the material has formed a stable three-dimensional network structure, exhibiting typical elastic gel characteristics. In summary, the rheological test results clearly demonstrate that the material of this invention has successfully achieved an effective transformation from a low-viscosity fluid to a high-strength elastic gel.

[0078] IV. The self-healing materials prepared in Examples 1-3 and Comparative Examples 4-21 were subjected to gelation time and post-gelation viscosity tests. The results are shown in the table below. Figure 6 The self-healing materials prepared in Examples 1-3 and Comparative Examples 22-33 were subjected to gelation time and post-gelation viscosity tests. The results are shown in the table below. Figure 7 .

[0079] Depend on Figure 6-7 It can be seen that by using the formulation of the present invention, a self-healing material with suitable gelation time and viscosity after gelation can be obtained.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A self-healing material for loess slope cracks based on the viscosity improvement of natural adhesives, characterized in that, It includes natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid, water, and pH adjuster; wherein, the natural gum is a natural polysaccharide containing cis-ortho-hydroxyl groups; and the crosslinking agent is a boron-containing compound.

2. The self-healing material for loess slope cracks based on natural adhesive viscosity according to claim 1, characterized in that, The mass ratio of natural gum, non-aqueous dispersant, crosslinking agent, crosslinking aid and water is 120-130:145-155:280-320:180-220:3000-3500.

3. The self-healing material for loess slope cracks based on natural adhesive viscosity according to claim 1, characterized in that, The amount of pH adjuster used is to adjust the pH value of the system to 7-9.

4. The self-healing material for loess slope cracks based on natural adhesive viscosity according to claim 1 or 2, characterized in that, Natural gum is at least one of carrageenan, guar gum, guar gum, locust bean gum, and sodium alginate.

5. The self-healing material for loess slope cracks based on natural adhesive viscosity according to claim 1 or 2, characterized in that, The non-aqueous dispersant is a saturated alkane nonpolar liquid or an oxygen-containing organic liquid.

6. The self-healing material for loess slope cracks based on natural adhesive viscosity according to claim 1 or 2, characterized in that, The crosslinking agent is at least one of sodium tetraborate, boric acid, and organic borate ester.

7. The self-healing material for loess slope cracks based on natural adhesive viscosity according to claim 1 or 2, characterized in that, The cross-linking aid is a water-soluble small molecule containing multiple hydroxyl groups.

8. The self-healing material for loess slope cracks based on natural adhesive viscosity according to claim 1 or 3, characterized in that, The pH adjuster is an organic acid solution.

9. The preparation method of the self-healing material for loess slope cracks based on the natural adhesive viscosity according to any one of claims 1-8, characterized in that, Includes the following steps: (1) Preparation of base slurry: Add crosslinking agent and crosslinking aid to non-aqueous dispersant in sequence, stir evenly, then add natural gum under stirring conditions, continue stirring to form a uniform suspension slurry, then add water, and then stir to obtain base slurry; (2) Add a pH adjuster to the base slurry obtained in step (1) to obtain a mortar, which is a self-repairing material for loess slope cracks based on the natural adhesive.

10. The application of the self-healing material for loess slope cracks based on natural adhesive viscosity as described in any one of claims 1-8 in the self-healing of loess slope cracks.

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