A preparation process for E-Alg-PHEMA and a grouting material for high-toughness, high-flowability semi-flexible pavement.

Abstract

This invention relates to the field of cement-based building materials technology, specifically disclosing a preparation process of E-Alg-PHEMA and a grouting material for high-toughness, high-flowability semi-flexible pavements. The process includes: (1) adding 1,2-epoxyhexane to an alkaline alginate solution and heating and stirring to react. After completion, the pH of the system is adjusted to neutral or acidic, and then alcohol precipitation is performed. The precipitate is separated, washed, dried, and ground to obtain modified sodium alginate powder. (2) The modified sodium alginate powder is dispersed in water to form a suspension, and then an initiator is added to react to obtain a pre-reaction system. (3) The pre-reaction system is heated in a protective atmosphere and HEMA monomer and crosslinking agent are added dropwise to react. The solid product is separated, washed, and freeze-dried to obtain E-Alg-PHEMA. This invention enables the grouting material to have both high flowability and high strength and toughness, effectively improving the mechanical properties of semi-flexible pavements.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cement-based building materials, and particularly relates to a preparation process of E-Alg-PHEMA and a grouting material for high-toughness high-flow semi-flexible pavement. BACKGROUND

[0002] The information disclosed in this BACKGROUND section is only for the purpose of increasing the understanding of the general background of the present application and should not be taken as an acknowledgement or any form of suggestion that this information forms prior art with respect to any country.

[0003] Roads are the most important part of modern transportation, and the selection of pavement materials greatly affects the service life and driving experience of roads. The commonly used pavement materials at present include asphalt concrete and cement concrete. However, the asphalt concrete has weak resistance to deformation and rutting after being subjected to multiple compactions or heavy compactions. The cement concrete has a long curing time during construction and is prone to cracking and sedimentation during use, which greatly reduces the actual service life compared with the designed service life.

[0004] Semi-flexible pavement is a new type of pavement structure with rigidity and flexibility, which is composed of a large-pore asphalt mixture matrix and a cement-based grouting material with high fluidity. This pavement structure combines the flexibility of asphalt pavement and the rigidity of cement concrete, retaining the advantages of asphalt pavement such as comfort and no joints, and having the characteristics of cement concrete such as high bearing capacity and good rutting resistance. However, the commercial semi-flexible pavement grouting material still has problems such as low flowability that cannot be filled into the pores or high fluidity that cannot be mixed with reinforcing fibers, which affects the bending and flexural resistance of the formed semi-flexible pavement. SUMMARY

[0005] In view of the above problems, the present application provides a preparation process of E-Alg-PHEMA and a grouting material for high-toughness high-flow semi-flexible pavement. The E-Alg-PHEMA makes the grouting material have high fluidity and high toughness, effectively improving the mechanical properties of the semi-flexible pavement. Specifically, the present application discloses the technical scheme as shown below.

[0006] Firstly, the present application provides a preparation process of E-Alg-PHEMA, which comprises the following steps:

[0007] (1) 1,2-epoxyhexane is added to an alkaline alginate solution for modification treatment, and the system is stirred under heating conditions. After completion, the pH of the system is adjusted to neutral or acidic, and the obtained reaction liquid is cooled to room temperature and subjected to alcohol precipitation treatment. The precipitate is separated, washed, dried, and pulverized to obtain modified sodium alginate powder (E-Alg).

[0008] (2) The modified sodium alginate powder is dispersed into water to form a suspension, and after deoxidation treatment, an initiator is added in a protective atmosphere for stirring reaction to obtain a pre-reaction system.

[0009] (3) The pre-reaction system is heated in a protective atmosphere, and then methyl methacrylate-2-hydroxyethyl ester (HEMA) monomer and a crosslinking agent are added dropwise for reaction. After completion, the solid product is separated, washed, and then freeze-dried to obtain the E-Alg-PHEMA.

[0010] Further, in step (1), the pH of the sodium alginate solution is 10-12. Optionally, the pH of the sodium alginate solution is adjusted to the set range by using a lye and an acid. The lye includes at least one of a NaOH solution, a Na2CO3 solution, etc., and the acid includes at least one of dilute hydrochloric acid, dilute nitric acid, etc.

[0011] Further, in step (1), the mass ratio of 1,2-epoxyhexane to sodium alginate is 0.1-0.5:1.

[0012] Further, in step (1), the heating temperature is 40-70°C, and the stirring reaction time is 3-6 hours. Optionally, the stirring rate is 300-600 rpm.

[0013] Further, in step (1), the pH of the system is adjusted to 6.5-7.0.

[0014] Further, in step (1), the reaction liquid is added to anhydrous ethanol for alcohol precipitation. Optionally, the volume ratio of the reaction liquid to anhydrous ethanol is 1:3-5.

[0015] Further, in step (1), the drying method includes drying at 40-50°C to a constant weight, etc. Optionally, the fineness of the modified sodium alginate powder is 100-200 mesh.

[0016] Further, in step (2), the mass ratio of the modified sodium alginate powder to water is 1-5:100.

[0017] Further, in step (2), the addition amount of the initiator is 0.5-2% of the mass of the modified sodium alginate powder. Optionally, the initiator includes at least one of ammonium persulfate (APS), azobisisobutyronitrile (AIBN), etc.

[0018] Further, in step (2), the stirring reaction time is 5-10 min, and the stirring rate is 300-600 rpm. Optionally, the protective atmosphere includes at least one of nitrogen, argon, etc.

[0019] Furthermore, in step (3), the heating temperature is 50~70℃.

[0020] Further, the mass ratio of the 2-hydroxyethyl methacrylate (HEMA) monomer, crosslinking agent and modified sodium alginate powder in step (3) is 2~3:0.3~0.8:1.

[0021] Further, in step (3), the crosslinking agent includes at least one of ethylene glycol dimethacrylate (EGDMA), polyethylene glycol dimethacrylate (PEGDMA), and polyethylene glycol diacrylate (PEGDA).

[0022] Furthermore, in step (3), the reaction time is 2 to 4 hours.

[0023] Furthermore, in step (3), the fineness of the E-Alg-PHEMA is 100~200 mesh.

[0024] Secondly, this invention discloses a high-toughness, high-flow semi-flexible pavement grout, the raw material composition of which includes the following components: 75-90 parts by weight of sulfoaluminate cement, 10-15 parts by weight of silicate cement, 1-3 parts by weight of mineral powder, 1-1.5 parts by weight of gypsum, 0.75-1 parts by weight of water-reducing agent, 0.1-0.3 parts by weight of defoamer, 0.05-0.1 parts by weight of stabilizer, 0.1-0.5 parts by weight of early strength agent, 0.5-1.5 parts by weight of E-Alg-PHEMA, and 40-50 parts by weight of mixing water.

[0025] Furthermore, the gypsum includes at least one of anhydrite, fluorogypsum, phosphogypsum, etc.

[0026] Furthermore, the water-reducing agent includes at least one of the following: polycarboxylate water-reducing agent, naphthalene-based water-reducing agent, lignin sulfonate water-reducing agent, etc.

[0027] Furthermore, the defoamer includes at least one of the following: silicone defoamer, ether defoamer, polyether defoamer, etc.

[0028] Further, the stabilizer includes at least one of cellulose ether, bentonite, amylase, etc. Optionally, the cellulose ether includes at least one of hydroxymethyl cellulose, carboxymethyl cellulose, etc.

[0029] Furthermore, the early strength agent includes at least one of calcium chloride, calcium sulfate, lithium sulfate, triethanolamine, etc.

[0030] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0031] As a pavement material, semi-flexible pavement grouting requires shortened construction time, but current grouting materials suffer from the inability to simultaneously achieve both workability and early strength. Furthermore, because semi-flexible pavement grouting materials require high fluidity to ensure sufficient filling of the matrix pores, fibers incorporated into the grout tend to settle at the bottom, making uniform dispersion difficult and significantly limiting the effectiveness of using fibers to toughen and modify the grouting material. Therefore, this invention uses a prepared E-Alg-PHEMA to improve the performance of semi-flexible pavement grouting materials. This allows it to maintain good fluidity and early strength while effectively preventing fiber settling, improving the grouting material's toughness, and thus providing better crack resistance and flexural strength during service, extending the pavement's service life. This is because: firstly, after incorporating the E-Alg-PHEMA into the grouting material, it first undergoes micro-water absorption, causing the outer layer to swell and partially dissolve, forming a viscoelastic softened swollen layer, while the core retains a relatively dense granular morphology, presenting a core-shell structure of "particle-hydrogel shell." As cement hydration proceeds, a large amount of Ca... 2+ After the polyvalent cations are released into the porous solution, they undergo ionic cross-linking with the carboxyl groups on the E-Alg-PHEMA macromolecular chain, causing the originally dispersed E-Alg segments to gradually cross-link into a three-dimensional hydrogel network on the particle surface and in the pores of the slurry. During this process, Na... + by Ca 2+ Plasma exchange transforms E-Alg from a readily soluble state into a sparingly soluble cross-linked calcium alginate hydrogel. The outer layer of the particles gradually evolves from a softened, swollen layer into a hydrogel shell with a certain strength and elasticity. Under the combined action of stirring shear force and cement paste flow shaping, the hydrogel shells between some swollen particles are stretched, pulled, and overlapped to form numerous slender gel strips and filamentous structures. These structures, under continuous Ca2+ exchange, transform from a readily soluble state into a spalled, elastic, and fibrous structure. 2+ Further solidification under the filling of crosslinking and hydration products ultimately constructs a Ca-Alg network gel structure composed of "calcium alginate fibers + gel film" within the slurry, realizing the in-situ transformation of sodium alginate from discrete particles to a continuous fiber network. This network gel structure can effectively improve interfacial bonding, absorb crack energy, and homogenize the stress field, thereby improving the flexural strength and overall toughness of the grout of this invention. On the other hand, the sodium alginate in the E-Alg-PHEMA is also modified with 1,2-epoxyhexane, which can reduce the number of hydroxyl groups on sodium alginate without affecting the carboxyl groups, maintaining the calcium content of sodium alginate. 2+The responsiveness of the grout is improved, and the hydrophobicity of sodium alginate is enhanced, thereby appropriately reducing the water absorption capacity of the Ca-Alg network gel structure. This ensures good flowability of the grout while also helping to avoid microcracks caused by excessive water release from the Ca-Alg network gel structure, which leads to volume shrinkage and decreased mechanical properties. Furthermore, the PHEMA outer shell of the E-Alg-PHEMA in this invention can achieve a "roller effect," increasing the flowability of the grout. Simultaneously, the PHEMA outer shell expands after slowly absorbing water in the grout, forming a semi-permeable membrane effect, which... 2+ Ions undergo localized cross-linking with E-Alg through the shell layer, forming a gel layer along the permeable channels on the outer shell before advancing inward, ultimately forming heterogeneously cross-linked chain-like and bundle-like gel fibers. This reaction-transformed fiber replaces traditional fibers, avoiding the contradiction of reducing the moisture content of the grout to address fiber settling, which would otherwise degrade the grout's flowability. Furthermore, the surface hydroxyl groups of the PHEMA outer shell layer can react with Ca... 2+ The ions exhibit slight complexation and are adsorbed and linked to CSH gel, Ca(OH)2, etc. by van der Waals forces, forming a certain interfacial bonding layer on the surface of the PHEMA outer shell, which promotes interfacial anchoring with the cement phase, thereby improving the mechanical properties of the grouting volume of the present invention. Attached Figure Description

[0032] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0033] Figure 1 The image shows an E-Alg-PHEMA sample prepared in Example 1 below.

[0034] Figure 2 The following is a diagram showing the flexural strength test results for Example 1.

[0035] Figure 3 The following is a diagram showing the compressive strength test results for Example 1.

[0036] Figure 4 The image shows an E-Alg-PHEMA sample prepared in Example 2 below.

[0037] Figure 5 The following is a diagram showing the flexural strength test results for Example 2.

[0038] Figure 6 The following is a diagram showing the compressive strength test results for Example 2.

[0039] Figure 7 The image shows an E-Alg-PHEMA sample prepared in Example 3 below.

[0040] Figure 8 The following is a diagram showing the flexural strength test results for Example 3.

[0041] Figure 9 The following is a diagram showing the compressive strength test results for Example 3.

[0042] Figure 10 The image shows an E-Alg-PHEMA sample prepared in Example 4 below.

[0043] Figure 11 The following is a diagram showing the flexural strength test results for Example 4.

[0044] Figure 12 The following is a diagram showing the compressive strength test results for Example 4.

[0045] Figure 13 The image shows a sample of the powder product prepared in Example 5 below.

[0046] Figure 14 The following is a diagram showing the flexural strength test results for Example 5.

[0047] Figure 15 The following is a diagram showing the compressive strength test results for Example 5.

[0048] Figure 16 The following is a diagram showing the flexural strength test results for Example 6.

[0049] Figure 17 The following is a diagram showing the compressive strength test results for Example 6.

[0050] Figure 18 The image shows the E-Alg sample prepared in Example 7 below.

[0051] Figure 19 The following is a diagram showing the flexural strength test results for Example 7.

[0052] Figure 20 The following is a diagram showing the compressive strength test results for Example 7. Detailed Implementation

[0053] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer.

[0054] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as those skilled in the art. All reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they shall be used in accordance with conventional methods in the art or as per the product instructions.

[0055] Furthermore, any methods and materials similar to or equivalent to those described herein can be applied to the method of this invention. The technical solution of this invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0056] Example 1: A preparation process for a high-toughness, high-flowability semi-flexible pavement grout, comprising the following steps:

[0057] (1) The pH of a 2 wt.% sodium alginate solution was adjusted to 12 using a combination of dilute hydrochloric acid and NaOH solution. Then, 1,2-epoxyhexane was added to the sodium alginate solution at a mass ratio of 0.35:1, and the mixture was heated to 60°C and stirred continuously at 500 rpm for 4.5 hours. After the reaction was completed, the system was adjusted to neutral, and the resulting reaction solution was cooled to room temperature and mixed with anhydrous ethanol at a volume ratio of 1:5. After standing for 30 minutes, the precipitate was separated by filtration, washed twice with anhydrous ethanol, and dried under vacuum at 40°C to constant weight. The precipitate was then ground through a 200-mesh sieve to obtain modified sodium alginate powder (E-Alg).

[0058] (2) The modified sodium alginate powder and deionized water were mixed at a mass ratio of 3:100 and ultrasonically treated for 15 min to obtain a suspension. Then, nitrogen gas was introduced for protection and deoxygenation treatment. After completion, ammonium persulfate (1.5% of the mass of the modified sodium alginate powder) was added in a nitrogen protective atmosphere and stirred continuously at a rate of 500 rpm for 10 min to obtain a pre-reaction system.

[0059] (3) Continue heating the pre-reaction system to 70°C under a nitrogen protective atmosphere. Then, add the components according to a mass ratio of 2-hydroxyethyl methacrylate (HEMA) monomer, the modified sodium alginate powder, and the crosslinking agent (ethylene glycol dimethacrylate) of 2:1:0.3. Stir until homogeneous and react for 2.5 hours. After completion, cool to room temperature, centrifuge to separate the solid product, wash with deionized water and anhydrous ethanol alternately (three times in total), then freeze-dry, and pass through a 200-mesh sieve to obtain E-Alg-PHEMA (e.g., ...). Figure 1 (As shown).

[0060] (4) Take the following proportions of raw materials: 80 parts by weight of 42.5 sulfoaluminate cement, 13 parts by weight of 42.5 ordinary silicate cement, 2 parts by weight of mineral powder, 1.2 parts by weight of fluorogypsum, 0.9 parts by weight of polycarboxylate superplasticizer, 0.15 parts by weight of organosilicon defoamer, 0.07 parts by weight of stabilizer (hydroxymethyl cellulose), 0.35 parts by weight of early strength agent (triethanolamine), 1.0 parts by weight of E-Alg-PHEMA prepared in this embodiment, and 46 parts by weight of mixing water.

[0061] (5) First, mix the E-Alg-PHEMA, water-reducing agent and mixing water and stir for 3 minutes. Then add the sulfoaluminate cement, ordinary silicate cement, mineral powder, gypsum, defoamer, stabilizer and early strength agent and stir for 2 minutes to obtain the grouting material.

[0062] Performance Testing: 1. The flow time of the grout prepared in this embodiment was tested according to DB37 / T 4681—2023 "Technical Specification for Application of Injectable Semi-Flexible Composite Pavement" to measure its workability / flowability. 2. The 3-day flexural and compressive strengths of the grout prepared in this embodiment were tested according to JCT 3420-2020 "Test Procedures for Cement and Cement Concrete in Highway Engineering" (as shown in Figures 1-2). Figure 2 , 3 (As shown), the results are shown in the table below:

[0063]

[0064] Example 2: A preparation process for a high-toughness, high-flowability semi-flexible pavement grout, comprising the following steps:

[0065] (1) The pH of a 2 wt.% sodium alginate solution was adjusted to 10 using a combination of dilute hydrochloric acid and Na2CO3 solution. Then, 1,2-epoxyhexane was added to the sodium alginate solution at a mass ratio of 0.5:1, and the mixture was heated to 40°C and stirred continuously at 300 rpm for 6 hours. After the reaction was completed, the pH of the system was adjusted to 6.5. The resulting reaction solution was cooled to room temperature and mixed with anhydrous ethanol at a volume ratio of 1:4. After standing for 30 min, the precipitate was separated by filtration, washed twice with anhydrous ethanol, and dried under vacuum at 50°C to constant weight. The precipitate was then ground through a 200-mesh sieve to obtain modified sodium alginate powder (E-Alg).

[0066] (2) The modified sodium alginate powder and deionized water were mixed at a mass ratio of 1:100 and ultrasonically treated for 15 min to obtain a suspension. Then, nitrogen gas was introduced for protection and deoxygenation treatment. After completion, ammonium persulfate (0.5% of the mass of the modified sodium alginate powder) was added in a nitrogen protective atmosphere and the mixture was stirred continuously at a rate of 300 rpm for 8 min to obtain a pre-reaction system.

[0067] (3) Continue heating the pre-reaction system to 60°C under a nitrogen protective atmosphere. Then, add the components according to a mass ratio of 3:1:0.8 for 2-hydroxyethyl methacrylate (HEMA) monomer, the modified sodium alginate powder, and the crosslinking agent (polyethylene glycol dimethacrylate). Stir until homogeneous and react for 4 hours. After completion, cool to room temperature, centrifuge to separate the solid product, wash with deionized water and anhydrous ethanol alternately (three times in total), then freeze-dry, and pass through a 200-mesh sieve to obtain E-Alg-PHEMA (e.g., ...). Figure 4 (As shown).

[0068] (4) Take the following proportions of raw materials: 75 parts by weight of 42.5 sulfoaluminate cement, 10 parts by weight of 42.5 ordinary silicate cement, 1 part by weight of mineral powder, 1 part by weight of phosphogypsum, 0.75 parts by weight of polycarboxylate superplasticizer, 0.1 parts by weight of polyether defoamer, 0.05 parts by weight of stabilizer (carboxymethyl cellulose), 0.1 parts by weight of early strength agent (calcium chloride), 0.5 parts by weight of E-Alg-PHEMA prepared in this embodiment, and 40 parts by weight of mixing water.

[0069] (5) First, mix the E-Alg-PHEMA, water-reducing agent and mixing water and stir for 3 minutes. Then add the sulfoaluminate cement, ordinary silicate cement, mineral powder, gypsum, defoamer, stabilizer and early strength agent and stir for 2 minutes to obtain the grouting material.

[0070] Performance testing: The outflow time and 3-day flexural and compressive strength of the grout prepared in this embodiment were tested using the same method as in Example 1 above (as shown in Figure 1). Figure 5 , 6 (As shown), the results are shown in the table below:

[0071]

[0072] Example 3: A preparation process for a high-toughness, high-flowability semi-flexible pavement grout, comprising the following steps:

[0073] (1) The pH of a 2 wt.% sodium alginate solution was adjusted to 11 using a combination of dilute nitric acid and Na2CO3 solution. Then, 1,2-epoxyhexane was added to the sodium alginate solution at a mass ratio of 0.1:1, and the mixture was heated to 70°C and stirred continuously at 600 rpm for 3 hours. After the reaction was completed, the system was adjusted to neutral, and the resulting reaction solution was cooled to room temperature and mixed with anhydrous ethanol at a volume ratio of 1:3. After standing for 30 min, the precipitate was separated by filtration, washed twice with anhydrous ethanol, and then vacuum dried (at 45°C) to constant weight. The precipitate was then ground through a 100-mesh sieve to obtain modified sodium alginate powder (E-Alg).

[0074] (2) The modified sodium alginate powder and deionized water were mixed at a mass ratio of 5:100 and ultrasonically treated for 15 min to obtain a suspension. Then, nitrogen gas was introduced for protection and deoxygenation treatment. After completion, azobisisobutyronitrile (2% of the mass of the modified sodium alginate powder) was added in a nitrogen protective atmosphere, and the mixture was stirred continuously at a rate of 800 rpm for 5 min to obtain a pre-reaction system.

[0075] (3) Continue heating the pre-reaction system to 50°C under a nitrogen protective atmosphere. Then, add the components according to a mass ratio of 2.5:1:0.7 for 2-hydroxyethyl methacrylate (HEMA) monomer, the modified sodium alginate powder, and the crosslinking agent (polyethylene glycol diacrylate). Stir well and react for 2 hours. After completion, cool to room temperature, centrifuge to separate the solid product, wash it alternately with deionized water and anhydrous ethanol (three times in total), then freeze-dry, and pass through a 100-mesh sieve to obtain E-Alg-PHEMA (e.g., ...). Figure 7 (As shown).

[0076] (4) Take the following proportions of raw materials: 90 parts by weight of 42.5 sulfoaluminate cement, 15 parts by weight of 42.5 ordinary silicate cement, 3 parts by weight of mineral powder, 1.5 parts by weight of anhydrite, 1 part by weight of sodium lignosulfonate water-reducing agent, 0.3 parts by weight of polyether defoamer, 0.1 parts by weight of stabilizer (bentonite), 0.5 parts by weight of early strength agent (lithium sulfate), 1.5 parts by weight of E-Alg-PHEMA prepared in this embodiment, and 50 parts by weight of mixing water.

[0077] (5) First, mix the E-Alg-PHEMA, water-reducing agent and mixing water and stir for 3 minutes. Then add the sulfoaluminate cement, ordinary silicate cement, mineral powder, gypsum, defoamer, stabilizer and early strength agent and stir for 2 minutes to obtain the grouting material.

[0078] Performance testing: The outflow time and 3-day flexural and compressive strength of the grout prepared in this embodiment were tested using the same method as in Example 1 above (as shown in Figure 1). Figure 8 , 9 (As shown), the results are shown in the table below:

[0079]

[0080] Example 4: A preparation process for a semi-flexible pavement grout, the same as in Example 1 above, except that the E-Alg-PHEMA in this example is prepared using the following method:

[0081] (1) Sodium alginate powder and deionized water were mixed at a mass ratio of 3:100 and ultrasonically treated for 15 min to obtain a suspension. Then nitrogen gas was introduced for protection and deoxygenation treatment. After completion, ammonium persulfate (1.5% of the mass of the modified sodium alginate powder) was added in a nitrogen protective atmosphere and stirred continuously at a rate of 500 rpm for 10 min to obtain a pre-reaction system.

[0082] (2) Continue heating the pre-reaction system to 70°C under a nitrogen protective atmosphere. Then, add the components according to a mass ratio of 2-hydroxyethyl methacrylate (HEMA) monomer, the modified sodium alginate powder, and the crosslinking agent (ethylene glycol dimethacrylate) of 2:1:0.3. Stir until homogeneous and react for 2.5 hours. After completion, cool to room temperature, centrifuge to separate the solid product, wash with deionized water and anhydrous ethanol alternately (three times in total), then freeze-dry, and pass through a 200-mesh sieve to obtain E-Alg-PHEMA (e.g., ...). Figure 10 (As shown).

[0083] Performance testing: The outflow time and 3-day flexural and compressive strength of the grout prepared in this embodiment were tested using the same method as in Example 1 above (as shown in Figure 1). Figure 11 , 12 (As shown), the results are shown in the table below:

[0084]

[0085] Example 5: A preparation process for a semi-flexible pavement grout, comprising the following steps:

[0086] (1) The pH of a 2 wt.% sodium alginate solution was adjusted to 12 using a combination of dilute hydrochloric acid and NaOH solution. Then, 1,2-epoxyhexane was added to the sodium alginate solution at a mass ratio of 0.35:1, and the mixture was heated to 60°C and stirred continuously at 500 rpm for 4.5 hours. After the reaction was completed, the system was adjusted to neutral, and the resulting reaction solution was cooled to room temperature and mixed with anhydrous ethanol at a volume ratio of 1:5. After standing for 30 minutes, the precipitate was separated by filtration, washed twice with anhydrous ethanol, and dried under vacuum at 40°C to constant weight. The precipitate was then ground through a 200-mesh sieve to obtain modified sodium alginate powder (E-Alg).

[0087] (2) The modified sodium alginate powder and deionized water were mixed at a mass ratio of 3:100 and ultrasonically treated for 15 min to obtain a suspension. Then, nitrogen gas was introduced for protection and deoxygenation. After completion, ammonium persulfate (1.5% of the mass of the modified sodium alginate powder) was added under a nitrogen protective atmosphere, and the mixture was continuously stirred at 500 rpm for 10 min. After completion, the mixture was cooled to room temperature, the solid product was separated, freeze-dried, and passed through a 200-mesh sieve to obtain a powder product (e.g., ...). Figure 13 (As shown).

[0088] (3) Take the following proportions of raw materials: 80 parts by weight of 42.5 sulfoaluminate cement, 13 parts by weight of 42.5 ordinary silicate cement, 2 parts by weight of mineral powder, 1.2 parts by weight of fluorogypsum, 0.9 parts by weight of polycarboxylate superplasticizer, 0.15 parts by weight of organosilicon defoamer, 0.07 parts by weight of stabilizer (hydroxymethyl cellulose), 0.35 parts by weight of early strength agent (triethanolamine), 1.0 part by weight of the powder product prepared in this embodiment, and 46 parts by weight of mixing water.

[0089] (4) First, mix the E-Alg-PHEMA, water-reducing agent and mixing water and stir for 3 minutes. Then add the sulfoaluminate cement, ordinary silicate cement, mineral powder, gypsum, defoamer, stabilizer and early strength agent and stir for 2 minutes to obtain the grouting material.

[0090] Performance testing: The outflow time and 3-day flexural and compressive strength of the grout prepared in this embodiment were tested using the same method as in Example 1 above (as shown in Figure 1). Figure 14 , 15 (As shown), the results are shown in the table below:

[0091]

[0092] Example 6: A preparation process for a semi-flexible pavement grout, comprising the following steps:

[0093] (1) Take the following proportions of raw materials: 75 parts by weight of 42.5 sulfoaluminate cement, 10 parts by weight of 42.5 ordinary silicate cement, 1 part by weight of mineral powder, 1 part by weight of phosphogypsum, 0.75 parts by weight of polycarboxylate superplasticizer, 0.1 parts by weight of polyether defoamer, 0.05 parts by weight of stabilizer (carboxymethyl cellulose), 0.1 parts by weight of early strength agent (calcium chloride), 0.5 parts by weight of glass fiber, and 40 parts by weight of mixing water.

[0094] (2) First, mix the glass fiber, water-reducing agent and mixing water and stir for 3 minutes. Then add the sulfoaluminate cement, ordinary silicate cement, mineral powder, gypsum, defoamer, stabilizer and early strength agent and stir for 2 minutes to obtain the grouting material.

[0095] Performance testing: The outflow time and 3-day flexural and compressive strength of the grout prepared in this embodiment were tested using the same method as in Example 1 above (as shown in Figure 1). Figure 16 , 17 (As shown), the results are shown in the table below:

[0096]

[0097] Example 7: A preparation process for a semi-flexible pavement grout, comprising the following steps:

[0098] (1) The pH of a 2 wt.% sodium alginate solution was adjusted to 11 using a combination of dilute nitric acid and Na2CO3 solution. Then, 1,2-epoxyhexane was added to the sodium alginate solution at a mass ratio of 0.1:1, and the mixture was heated to 70°C and continuously stirred at 600 rpm for 3 hours. After the reaction was completed, the system was adjusted to neutral, and the resulting reaction solution was cooled to room temperature and mixed with anhydrous ethanol at a volume ratio of 1:3. The mixture was then allowed to stand for 30 minutes for alcohol precipitation. After precipitation, the precipitate was separated by filtration, washed twice with anhydrous ethanol, and then vacuum dried (at 45°C) to constant weight. Finally, the precipitate was ground through a 100-mesh sieve to obtain the product shown below. Figure 18 The modified sodium alginate powder shown is E-Alg.

[0099] (2) Take the following proportions of raw materials: 90 parts by weight of 42.5 sulfoaluminate cement, 15 parts by weight of 42.5 ordinary silicate cement, 3 parts by weight of mineral powder, 1.5 parts by weight of anhydrite, 1 part by weight of sodium lignosulfonate water-reducing agent, 0.3 parts by weight of polyether defoamer, 0.1 parts by weight of stabilizer (bentonite), 0.5 parts by weight of early strength agent (lithium sulfate), 1.5 parts by weight of E-Alg prepared in this embodiment, and 50 parts by weight of mixing water.

[0100] (3) First, mix the E-Alg-PHEMA, water-reducing agent and mixing water and stir for 3 minutes. Then add the sulfoaluminate cement, ordinary silicate cement, mineral powder, gypsum, defoamer, stabilizer and early strength agent and stir for 2 minutes to obtain the grouting material.

[0101] Performance testing: The outflow time and 3-day flexural and compressive strength of the grout prepared in this embodiment were tested using the same method as in Example 1 above (as shown in Figure 1). Figure 19 , 20 (As shown), the results are shown in the table below:

[0102]

[0103] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. 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 process for the preparation of E-Alg-PHEMA, characterized in that, The method comprises the following steps: (1) adding 1,2-epoxyhexane into an alkaline alginate solution for modification treatment, and stirring under heating condition; after completion, adjusting the pH of the system to neutral or acidic, cooling the obtained reaction liquid to room temperature, and then performing alcohol precipitation treatment, washing and drying the obtained precipitate, and grinding to obtain modified sodium alginate powder; (2) dispersing the modified sodium alginate powder into water to form a suspension, adding an initiator after deoxidation treatment and stirring in a protective atmosphere to obtain a pre-reaction system; (3) adding 2-hydroxyethyl methacrylate monomer and a crosslinking agent into the pre-reaction system after heating in a protective atmosphere, and then performing reaction; after completion, washing the obtained solid product, and then freeze-drying to obtain the E-Alg-PHEMA.

2. The process for the preparation of E-Alg-PHEMA as claimed in claim 1, wherein, In step (1), the pH of the alginate solution is 10-12.

3. The process for the preparation of E-Alg-PHEMA as claimed in claim 1, wherein, In step (1), the mass ratio of 1,2-epoxyhexane to sodium alginate is 0.1-0.5:

1. Alternatively, in step (1), the heating temperature is 40-70°C, and the stirring reaction time is 3-6 hours. Alternatively, in step (1), the stirring rate is 300-600 rpm.

4. The process for the preparation of E-Alg-PHEMA as claimed in claim 1, wherein, In step (1), the pH of the system is adjusted to 6.5-7.

0. Alternatively, in step (1), the reaction liquid is added into anhydrous ethanol for alcohol precipitation; the volume ratio of the reaction liquid to anhydrous ethanol is 1:3-5. Alternatively, in step (1), the drying method comprises drying at 40-50°C until the weight is constant. Alternatively, in step (1), the fineness of the modified sodium alginate powder is 100-200 mesh.

5. The process for the preparation of E-Alg-PHEMA as claimed in claim 1, wherein, In step (2), the mass ratio of the modified sodium alginate powder to water is 1-5:

100.

6. The process for the preparation of E-Alg-PHEMA as claimed in claim 1, wherein, In step (2), the addition amount of the initiator is 0.5-2% of the mass of the modified sodium alginate powder. Alternatively, in step (3), the mass ratio of the 2-hydroxyethyl methacrylate monomer, the crosslinking agent and the modified sodium alginate powder in step (2) is 2-3:0.3-0.8:

1.

7. The process for the preparation of E-Alg-PHEMA according to any one of claims 1-6, characterized in that, In step (2), the initiator comprises at least one of ammonium persulfate and azobisisobutyronitrile. Alternatively, in step (2), the stirring reaction time is 5-10 min, and the stirring rate is 300-600 rpm. Alternatively, in step (3), the heating temperature is 50-70°C. Alternatively, in step (3), the crosslinking agent comprises at least one of ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate and polyethylene glycol diacrylate. Alternatively, in step (3), the reaction time is 2-4 hours. Alternatively, in step (3), the fineness of the E-Alg-PHEMA is 100-200 mesh.

8. A high-ductility high-flow semi-flexible pavement grout, characterized by, The raw material composition comprises the following components: 75-90 parts by weight of sulphoaluminate cement, 10-15 parts by weight of Portland cement, 1-3 parts by weight of mineral powder, 1-1.5 parts by weight of gypsum, 0.75-1 parts by weight of water reducing agent, 0.1-0.3 parts by weight of defoaming agent, 0.05-0.1 parts by weight of stabilizing agent, 0.1-0.5 parts by weight of early strength agent, 0.5-1.5 parts by weight of E-Alg-PHEMA obtained by the preparation process of any one of claims 1-7, and 40-50 parts by weight of mixing water.

9. The high-ductility high-flowing-state semi-flexible pavement grout according to claim 8, characterized by, The gypsum comprises at least one of anhydrite, fluorogypsum, and phosphogypsum; Alternatively, the water reducing agent comprises at least one of polycarboxylic acid water reducing agent, naphthalene water reducing agent, and lignin sulfonate water reducing agent. Alternatively, the defoaming agent comprises at least one of silicone defoaming agent, ether defoaming agent, and polyether defoaming agent.

10. The high-ductility high-flowing-state semi-flexible pavement grout according to claim 8 or 9, characterized by, The stabilizing agent comprises at least one of cellulose ether, bentonite, and amylase. Alternatively, the cellulose ether comprises at least one of methylol cellulose and carboxymethyl cellulose. Alternatively, the early strength agent comprises at least one of calcium chloride, calcium sulfate, lithium sulfate, and triethanolamine.

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