Modified PE fiber high-performance repair mortar and preparation method thereof
By mechanically grinding and chemically modifying the PE fibers and replacing some cement with silica fume, the problem of poor bonding performance between PE fibers and cement substrates is solved, and high-performance repair mortar is prepared, which improves compressive strength and crack resistance, and is suitable for repair in the construction field.
Patent Information
- Application Number
- CN202411420991.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-12
- Publication Date
- 2025-08-01
AI Technical Summary
The existing repair mortar has problems such as insufficient compressive strength, poor crack resistance and poor durability. The poor bonding performance and poor dispersion of PE fibers with cement substrates are limited, which limits its application in repair mortar.
By mechanically grinding the PE fibers, combined treatment of PVP aqueous solution and γ-aminopropyltriethoxysilane aqueous solution, a double-coat modification is formed to enhance the bonding performance of PE fibers and cement substrates. By introducing silicon fume to replace part of the cement, the preparation process is optimized to achieve uniform dispersion of PE fibers in the repair mortar.
The bonding and dispersion of PE fibers and cement substrates are significantly improved, and repair mortar with excellent compressive strength, crack resistance and durability is prepared, with good interface bonding and environmental protection, and is suitable for urban roads and bridge repairs.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of repair mortars, and in particular to a modified PE fiber high-performance repair mortar and a preparation method thereof. Background Art
[0002] With the rapid development of the construction industry, the performance requirements for building materials are becoming increasingly demanding. Repair mortar, an indispensable material in building maintenance and repair, has a direct impact on the building's service life and safety. Traditional repair mortars suffer from numerous limitations, such as insufficient compressive strength, poor crack resistance, and poor durability. These limitations have, to a certain extent, limited their application in the construction industry.
[0003] To improve the performance of repair mortars, many researchers have tried various methods, including adding different types of fibers to enhance the mortar's crack resistance and toughness. However, these methods often suffer from high costs, complex preparation processes, or limited enhancement effects.
[0004] Polyethylene (PE) fiber, as a lightweight, high-strength, and corrosion-resistant material, has been used in various fields. However, the application of PE fiber in repair mortars faces problems such as poor bonding performance with the cement matrix and poor dispersion, which limits the performance improvement of PE fiber in repair mortars. Summary of the Invention
[0005] The purpose of the present invention is to provide a modified PE fiber high-performance repair mortar and a preparation method thereof in order to solve the problems existing in the prior art. This method significantly improves the bonding performance of PE fibers and cement substrates through a specific surface modification technology. At the same time, through an optimized preparation process, the PE fibers are evenly dispersed in the repair mortar, thereby preparing a repair mortar with excellent compressive strength, crack resistance, and durability. The modified PE fiber high-performance repair mortar has good interfacial bonding, ductility, durability, and rapid hardening performance. At the same time, the modifier used in the modified PE fiber high-performance repair mortar provided by the present invention is non-toxic and environmentally friendly, which can reduce the impact on the environment.
[0006] The purpose of the present invention can be achieved by the following technical solutions:
[0007] A modified PE fiber high-performance repair mortar comprises the following components in parts by weight:
[0008]
[0009] The modification process of the modified PE fiber is as follows: mechanically polishing the PE fiber, treating it with a PVP aqueous solution, and treating it with a γ-aminopropyltriethoxysilane aqueous solution in sequence to obtain the modified PE fiber.
[0010] Further, the diameter of the PE fiber is 20 - 30 μm, the length is 8 - 14 mm, and its tensile strength is between 2800 - 3000 MPa after tensile testing.
[0011] Further, the specific modification process of the modified PE fiber is as follows:
[0012] S1. First, use medium - grit sandpaper to preliminarily polish the PE fiber, and then use fine - grit sandpaper to continue polishing to obtain PE fiber with uniform surface texture;
[0013] S2. Clean the polished PE fiber in step S1 with absolute ethanol and deionized water and then dry it to obtain dried PE fiber;
[0014] S3. Immerse the dried PE fiber in step S2 in an aqueous PVP solution, and at the same time perform ultrasonic treatment. After completion, perform drying treatment to obtain dried - after PE fiber;
[0015] S4. Immerse the dried - after PE fiber in step S3 in an aqueous solution of γ - aminopropyltriethoxysilane. After completion, perform drying treatment to obtain modified PE fiber.
[0016] Furthermore, in step S1, the mesh number range of the medium - grit sandpaper is 80 - 120 meshes, and the mesh number range of the fine - grit sandpaper is 180 - 240 meshes.
[0017] Furthermore, in step S3, the concentration range of the aqueous PVP solution is 2 - 5%.
[0018] Furthermore, in step S3, when the dried PE fiber is immersed in the aqueous PVP solution, the mass of the PE fiber immersed per liter of the aqueous PVP solution ranges from 10 - 20 g.
[0019] Furthermore, in step S3, the equipment used for ultrasonic treatment is an ultrasonic extractor, the ultrasonic frequency range is 20 kHz - 100 kHz, and the ultrasonic treatment time is 10 - 15 min.
[0020] Furthermore, in step S4, the concentration range of the aqueous solution of γ - aminopropyltriethoxysilane is 0.5% - 1%, and the soaking time is 10 - 15 min.
[0021] Furthermore, in step S4, when the dried - after PE fiber is immersed in the aqueous solution of γ - aminopropyltriethoxysilane, the mass of the PE fiber immersed per liter of the aqueous solution of γ - aminopropyltriethoxysilane ranges from 10 - 20 g.
[0022] Furthermore, in steps S3 and S4, the drying treatment is carried out in an oven, the temperature of the oven is 50-60 °C, and the drying duration is 3-4 h.
[0023] The modification principle of the modified PE fiber is as follows: First, use medium sandpaper with a mesh size of 80-120 to preliminarily polish the PE fiber to quickly increase its surface roughness; then use fine sandpaper with a mesh size of 180-240 to continue polishing to obtain a PE fiber with uniform surface texture; use absolute ethanol and deionized water to rinse the polished PE fiber to remove dust and stains left by the sandpaper on the surface of the PE fiber.
[0024] Furthermore, the cement is ordinary Portland cement with a grade of PO42.5;
[0025] The fly ash is Class I fly ash;
[0026] The silica fume has a specification of SF90;
[0027] The MB value of the stone powder is 1.0-1.4;
[0028] The high-range water reducer is a polycarboxylate superplasticizer.
[0029] In addition, the present invention also provides a preparation method for a modified PE fiber high-performance repair mortar, and the specific steps are as follows:
[0030] S1. Prepare modified PE fibers;
[0031] S2. Weigh cement, fly ash, silica fume, stone powder, high-range water reducer, modified PE fibers and water according to the mixing ratio;
[0032] S3. Mix the modified PE fibers with cement, fly ash, silica fume and stone powder, and dry mix them in a mixer to obtain a mixture, ensuring uniform distribution of the raw materials;
[0033] S4. Add water and high-range water reducer to the mixture obtained in step S3, and continue stirring to obtain a modified PE fiber high-performance repair mortar.
[0034] Furthermore, in steps S3 and S4, the stirring time is 2-3 minutes.
[0035] The principle of the present invention is as follows:
[0036] The present invention uses mechanical grinding, PVP aqueous solution, and γ-aminopropyltriethoxysilane aqueous solution to jointly treat and modify PE fibers, and prepares high-performance repair mortar by combining the modified PE fibers with materials such as cement, fly ash, and silica fume. Medium-fine sandpaper is used to grind the surface of the PE fibers successively to increase its surface roughness, improve the mechanical interlocking effect between the PE fibers and the cementitious materials, and increase its bonding strength; PVP molecules contain carbonyl groups and nitrogen atoms, and are attached to the surface of the PE fibers to form a PVP coating by the technical means provided by the present invention. The PVP coating forms a strong interaction with the hydroxyl groups in the cement matrix through hydrogen bonds, enhancing the interfacial bonding; γ-aminopropyltriethoxysilane forms silanols after hydrolysis, and undergoes a condensation reaction with the hydroxyl groups on the PVP coating to generate Si-O-Si and Si-O-C bonds, and a stable silane layer is formed after drying in an oven. The double coatings of γ-aminopropyltriethoxysilane and PVP are attached to the surface of the PE fibers, which not only improves the hydrophilicity of the PE fibers, but also forms a stable layer that can react with the cementitious materials, enhancing the interfacial bonding strength during the hydration reaction. At the same time, the γ-APS layer can prevent the penetration of moisture and gas, and overall improves the mechanical properties and durability of the modified PE fiber high-performance repair mortar under the synergistic effect of the two coatings; introducing silica fume to replace part of the cement in the cementitious materials significantly improves the early strength of the modified PE fiber high-performance repair mortar, and also has a good improvement on the later strength.
[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0038] (1) The present invention provides a modified PE fiber high-performance repair mortar and its preparation method. The repair mortar prepared after modification has good compressive properties, tensile properties, and high early strength. Compared with the repair mortar prepared from ordinary PE fibers, its interfacial bonding force is enhanced. After the tensile test, the surface cracks of the modified PE fiber high-performance repair mortar are narrower and more numerous, and it has better impermeability and corrosion resistance. The product provided by the present invention can be applied to the repair of urban roads and bridges, etc.
[0039] (2) The present invention provides a modified PE fiber high-performance repair mortar and its preparation method. The invention uses mechanical grinding, PVP aqueous solution, and γ-aminopropyltriethoxysilane aqueous solution to jointly treat and modify PE fibers, and introduces silica fume to replace part of the cement as a cementitious material to prepare the modified PE fiber high-performance repair mortar. The preparation process is easy to control, and the raw materials are easy to obtain, having the prospect of industrial application.
[0040] (3) The modifiers used in the present invention, namely PVP (polyvinylpyrrolidone) and γ-aminopropyltriethoxysilane, are both environmentally friendly modifiers, which can reduce environmental pollution during the preparation and production of the mortar. Detailed implementation mode
[0041] The present invention will be described in detail below in conjunction with specific embodiments. These embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation manners and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.
[0042] In the following embodiments, the sources of raw materials are as follows:
[0043] PE fibers were purchased from Wuhan, Hubei.
[0044] Absolute ethanol, PVP aqueous solution and γ-aminopropyltriethoxysilane aqueous solution were all purchased from Sinopharm.
[0045] Cement, fly ash and silica fume were purchased from Wuhan, Hubei. The cement was Huaxin PO42.5, the fly ash was grade I ash, and the silica fume was SF90.
[0046] Stone powder was purchased from Huaxin Cement Company in Macheng, Hubei, with an MB value of 1.0 - 1.4; the high-range water reducer was purchased from Huanggang, Hubei, and it was a polycarboxylate superplasticizer produced by Xijian New Materials.
[0047] For those not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. All the reagents used are conventional products that can be obtained through commercial purchase.
[0048] The following will describe in detail some embodiments of the present invention in conjunction with the attached tables. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.
[0049] In the following embodiments, a modified PE fiber high-performance repair mortar is prepared by the following steps (the raw material ratios and preparation process parameters of the embodiments and comparative examples are shown in Table 1):
[0050] 1) Use medium sandpapers with 80, 100, and 120 meshes to polish the PE fibers in sequence to quickly increase their surface roughness.
[0051] 2) Continue to polish with fine sandpapers with 180, 200, 220, and 240 meshes to obtain PE fibers with uniform surface texture.
[0052] 3) Rinse the polished PE fibers with absolute ethanol and deionized water to remove the dust and stains left by the sandpaper on the surface of the PE fibers.
[0053] 4) Place the PE fibers obtained in 3) in an oven at 60 °C for 4 h for drying.
[0054] 5) Immerse the PE fibers obtained in 4) in a PVP aqueous solution with a concentration range of 2% - 5%, and immerse 15 g of PE fibers in every 1 L of the PVP aqueous solution.
[0055] 6) Ultrasonic treatment of the PE fibers immersed in the PVP aqueous solution was performed using an ultrasonic extractor at an ultrasonic frequency of 80 kHz for 15 min. After the treatment, the PE fibers were removed and dried in an oven at 60° C. for 4 h.
[0056] 7) soaking the PE fiber obtained in 6) in a 0.5%-1% aqueous solution of γ-aminopropyltriethoxysilane, with 15 g of PE fiber soaked in 1 L of the γ-aminopropyltriethoxysilane aqueous solution for 15 minutes. After the treatment, the PE fiber was removed and dried in an oven at 60° C. for 4 hours to obtain a modified PE fiber;
[0057] 8) The modified PE fiber obtained in 7) was mixed with cement, fly ash, silica fume, and stone powder according to the components designed in the technical solution and dry stirred in a mixer for 3 minutes to ensure uniform distribution of the raw materials. Water and a high-efficiency water reducer were then added and stirred for another 3 minutes to obtain a modified PE fiber high-performance repair mortar.
[0058] Table 1 Raw material ratios (in parts by weight) in Examples 1 to 8 and Comparative Examples 1 to 7
[0059]
[0060] The modified PE fiber high-performance repair mortars obtained in Examples 1 to 8 and the PE fiber repair mortars obtained in Comparative Examples 1 to 7 were subjected to relevant performance tests, including 7d and 28d compressive strength tests, 28d tensile strength tests, contact angle tests, and crack morphology observations.
[0061] Table 2 Test results of repair mortar performance in Examples 1 to 8 and Comparative Examples 1 to 7
[0062]
[0063]
[0064] Through the analysis of Table 1 and Table 2, it can be obtained that the modified PE fiber high-performance repair mortar obtained in Examples 1-8 all adopted double-coating modification with PVP aqueous solution and γ-aminopropyltriethoxysilane aqueous solution. Compared with the PE fiber repair mortar obtained in Comparative Example 1 where the PE fiber was not modified, the compressive strength at 7 days and 28 days, the tensile strength at 28 days, and the number of cracks were all improved, and the contact angle and the average crack width after stretching were both reduced; among them, the compressive strength at 7 days and 28 days had the largest increase in Example 5, at this time the concentration of the PVP aqueous solution was 2%, and the concentration of the γ-aminopropyltriethoxysilane aqueous solution was 1%, and the increase amplitude reached 8.34%; the tensile strength at 28 days in Example 6 had the most obvious increase, at this time the concentration of the PVP aqueous solution was 3%, and the concentration of the γ-aminopropyltriethoxysilane aqueous solution was 1%, and the increase amplitude reached 36.76%; similarly, the contact angle was the smallest in Example 6, compared with Comparative Example 1, the contact angle decreased by 37.76%, indicating that the hydrophilicity of the PE fiber had a significant improvement; the number of cracks reached the maximum in Example 7, with an increase amplitude of 160%, and the average crack width reached the minimum in Example 5, with an amplitude of 36.06%. The reduction of the crack width can effectively improve the impermeability of the repair mortar, and the increase in the number of cracks indicates that the stress is more dispersed when the repair mortar bears tension, and the ductility and toughness of the material are both improved.
[0065] It can be found from the modified PE fiber high-performance repair mortar obtained according to Examples 1-8 and the modified PE fiber repair mortar prepared in Comparative Examples 2-7 that the repair mortar prepared by modifying the PE fiber with PVP solution or γ-aminopropyltriethoxysilane aqueous solution alone has a worse effect than the combined modification of the two. Its compressive strength at 7 days and 28 days and tensile strength are all smaller than the combined modification effect. On the contrary, it has a larger contact angle, fewer crack numbers and a larger average crack width, and its working performance is far inferior to the PE fiber repair mortar obtained by combined modification. Therefore, although the modified PE fiber repair mortar prepared in Comparative Examples 2-7 has a certain improvement compared with Comparative Example 1, the overall improvement amplitude is not large.
[0066] Through the analysis of the test results of Examples 1-8, the compressive strength at 7 days of the modified PE fiber high-performance repair mortar prepared by the present invention reached more than 83% of the compressive strength at 28 days. Among them, the modified PE fiber high-performance repair mortar prepared in Example 5 even reached 88%, indicating that the combined modification of the PVP solution and γ-aminopropyltriethoxysilane aqueous solution on the PE fiber improved the early rate of the hydration reaction. Therefore, the modified PE fiber high-performance repair mortar prepared by the present invention has high early strength and has a wider application scenario as a repair mortar.
[0067] From the observations of Examples 1-8 and Comparative Examples 2-7, it can be found that when the concentration of the PVP solution is 2%, the improvement of the compressive strength of the repair mortar is the most significant. When the concentration is 3%, the improvement of the tensile strength is the most significant. At the same time, when the concentration is 3%, whether it is the contact angle, the number of cracks or the average crack width, they are all optimal under the influence of the concentration of the γ-aminopropyltriethoxysilane aqueous solution. Keeping the concentration of the PVP solution unchanged, increasing the concentration of the γ-aminopropyltriethoxysilane aqueous solution from 0 to 1% also improves the performance of the repair mortar. However, too high a concentration of the γ-aminopropyltriethoxysilane aqueous solution will affect the workability of the mortar and cause inconvenience in construction. Therefore, the concentration range adopted in this application is 0.5%-1%. In addition, as a repair mortar, the concentration ratio of the PVP aqueous solution and the γ-aminopropyltriethoxysilane aqueous solution can be adjusted according to different application scenarios to achieve the purpose of modification.
[0068] Based on the research of the above examples and comparative examples, a comparative study was carried out on the influence of PE fibers on the performance of the repair mortar before and after grinding, using a PVP aqueous solution with a concentration of 3% and a γ-aminopropyltriethoxysilane aqueous solution with a concentration of 1%. An additional Comparative Example 8 was added as a performance control group for the PE fiber repair mortar prepared without directly grinding the PE fiber. Compared with Example 6, it only lacks the grinding step. The specific preparation steps are as follows:
[0069] 1) Immerse the PE fibers in a PVP aqueous solution with a concentration range of 3%. Immerse 15 g of PE fibers in every 1 L of the PVP aqueous solution.
[0070] 2) Use an ultrasonic extractor to perform ultrasonic treatment on the PE fibers immersed in the PVP aqueous solution. The ultrasonic frequency range is 80 kHz, and the ultrasonic treatment time is 15 min. After the treatment is completed, take out the PE fibers and place them in an oven at 60 °C for 4 h for drying.
[0071] 3) Immerse the PE fibers obtained in 2) in a γ-aminopropyltriethoxysilane aqueous solution with a concentration of 1%. Immerse 15 g of PE fibers in every 1 L of the γ-aminopropyltriethoxysilane aqueous solution, and the immersion time is 15 min. After the treatment is completed, take out the PE fibers and place them in an oven at 60 °C for 4 h for drying to obtain modified PE fibers.
[0072] 4) Mix the modified PE fibers obtained in 3) with cement, fly ash, silica fume, and stone powder according to the components designed in the technical solution and dry mix them in a mixer for 3 min to ensure uniform distribution of the raw materials. Then add water and a high-range water reducer and continue to stir for 3 minutes to obtain a modified PE fiber high-performance repair mortar.
[0073] The specific performance test results are shown in Table 3.
[0074] Table 3 Performance test results of Comparative Example 8
[0075]
[0076] Through the analysis of Example 6 and Comparative Example 8, it can be found that sanding the PE fibers can significantly improve the tensile strength of the repair mortar, with a 13.41% increase compared to Comparative Example 8. The influence on the compressive strength and contact angle is not obvious, but it is well reflected in the control of the crack number and average crack width. The specific surface area of the sanded PE fibers increases, enlarging the reaction area with the cementitious material. At the same time, there are grooves on the surface of the sanded PE fibers, forming a mechanical interlocking effect with the cementitious material and increasing the bonding strength.
[0077] In summary, the modified PE fiber high-performance repair mortar provided by the present invention has good compressive and tensile properties. When subjected to tensile force, it has a large number of surface cracks with narrow widths, which helps to disperse stress during the tensile process of the repair mortar material, and has good ductility and toughness. At the same time, it has good 7-day compressive strength, the raw materials for preparation are easily obtainable, and the preparation process is easy to control. It can be applied to a variety of engineering scenarios and has good application prospects.
[0078] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention should be within the protection scope of the present invention.
Claims
1. A modified PE fiber high-performance repair mortar, characterized in that, Comprising the following components in parts by weight: Among them, the modification process of the modified PE fiber is as follows: The PE fiber is successively subjected to mechanical grinding, treatment with a PVP aqueous solution, and treatment with a γ-aminopropyltriethoxysilane aqueous solution to obtain the modified PE fiber.
2. The high-performance repair mortar of a modified PE fiber according to claim 1, wherein The diameter of the PE fiber is 20 - 30 μm, the length is 8 - 14 mm, and its tensile strength is between 2800 - 3000 MPa after tensile testing.
3. The high-performance repair mortar of a modified PE fiber according to claim 1, characterized in that, The specific modification process of the modified PE fiber is as follows: S1. First, the PE fiber is preliminarily ground with medium sandpaper, and then continued to be ground with fine sandpaper to obtain a PE fiber with uniform surface texture. S2. The PE fiber ground in step S1 is cleaned with absolute ethanol and deionized water and then dried to obtain the dried PE fiber. S3. The dried PE fiber in step S2 is immersed in a PVP aqueous solution while ultrasonic treatment is carried out, and after completion, drying treatment is carried out to obtain the dried PE fiber. S4. The dried PE fiber in step S3 is soaked and treated with a γ-aminopropyltriethoxysilane aqueous solution, and after completion, drying treatment is carried out to obtain the modified PE fiber.
4. A modified PE fiber high-performance repair mortar according to claim 3, characterized in that, In step S1, the mesh number range of the medium sandpaper is 80 - 120 meshes, and the mesh number range of the fine sandpaper is 180 - 240 meshes.
5. A modified PE fiber high-performance repair mortar according to claim 3, characterized in that, In step S3, the concentration range of the PVP aqueous solution is 2 - 5%. When the dried PE fiber is immersed in the PVP aqueous solution, the mass of the PE fiber immersed in each liter of the PVP aqueous solution ranges from 10 - 20 g. The equipment used for the ultrasonic treatment is a ultrasonic extractor, the ultrasonic frequency range is 20 kHz - 100 kHz, and the ultrasonic treatment time is 10 - 15 min.
6. The high-performance repair mortar made of modified PE fiber according to claim 3, characterized in that, In step S4, the concentration range of the γ-aminopropyltriethoxysilane aqueous solution is 0.5% - 1%, and the soaking time is 10 - 15 min. When the dried PE fiber is immersed in the γ-aminopropyltriethoxysilane aqueous solution, the mass of the PE fiber immersed in each liter of the γ-aminopropyltriethoxysilane aqueous solution ranges from 10 - 20 g.
7. A modified PE fiber high-performance repair mortar according to claim 3, characterized in that, In steps S3 and S4, the drying treatment is carried out in an oven, the temperature of the oven is 50 - 60 °C, and the drying duration is 3 - 4 h.
8. A modified PE fiber high-performance repair mortar according to claim 1, characterized in that, The cement is ordinary Portland cement with a grade of PO42.
5. The fly ash is grade I fly ash. The specification of the silica fume is SF90. The MB value of the stone powder is 1.0 - 1.
4. The high-range water reducer is a polycarboxylate superplasticizer.
9. A method for preparing a modified PE fiber high-performance repair mortar as described in any one of claims 1-8, characterized in that, The specific steps are as follows: S1. Prepare the modified PE fiber. S2. Weigh cement, fly ash, silica fume, stone powder, high-range water reducer, modified PE fiber and water according to the mix ratio. S3. The modified PE fiber is mixed with cement, fly ash, silica fume, and stone powder and then dry-mixed in a mixer to obtain a mixture, ensuring uniform distribution of the raw materials. S4. Water and the high-range water reducer are added to the mixture obtained in step S3, and stirring is continued to obtain the modified PE fiber high-performance repair mortar.
10. The preparation method of a modified PE fiber high-performance repair mortar according to claim 9, characterized in that, In steps S3 and S4, the stirring time is 2 - 3 minutes.