Multi-layer jute geotextile based on asphalt emulsion modification as well as preparation method and application of multi-layer jute geotextile

Abstract

The invention discloses a multi-layer jute geotextile based on asphalt emulsion modification and a preparation method and application thereof, and belongs to the technical field of civil engineering materials. Nano silicon dioxide is selected and dissolved in water to prepare nano material dispersion liquid; adding an emulsifier and a stabilizer into water to prepare liquid soap; heating the matrix asphalt, pouring into an asphalt tank, grinding, shearing and cooling to obtain emulsified asphalt; mixing water-borne epoxy resin and alkaline silica sol to obtain composite latex, adding the composite latex into the emulsified asphalt, and mixing to obtain modified emulsified asphalt; adding the nano material dispersion liquid into the modified emulsified asphalt, and stirring to obtain a modified asphalt emulsion; soaking the jute geotextile in a silane coupling agent solution, taking out and drying; mixing natural latex and petroleum resin emulsion to obtain a composite treatment solution, soaking the jute geotextile, and drying to obtain a modified jute geotextile; covering the modified jute geotextile with the modified asphalt emulsion, performing layered reinforcement to obtain a composite material, and compacting and curing to obtain a finished product. The modified asphalt emulsion is used for treating the jute geotextile, so that the tensile strength and the elastic modulus of the jute geotextile are remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of civil engineering materials, and particularly relates to a multi-layer jute geotextile modified by asphalt emulsion, its preparation method and application. Background Art

[0002] As a natural fiber-based material, jute fabric is widely used in slope protection, road reinforcement, riverbank erosion resistance and other fields in civil engineering due to its eco-friendliness, low cost and affinity with soil. Its porous structure can effectively promote vegetation growth and reduce the water flow velocity by intercepting surface runoff, thereby enhancing the soil and water conservation ability. Moreover, the high water absorption performance of jute fiber (water holding rate of about 500%) further enhances its role in soil improvement.

[0003] However, the natural jute fiber has the characteristic of rapid biodegradation, which will lead to insufficient durability. And it is vulnerable to microbial erosion when exposed to a humid soil environment for a long time, and its strength decays rapidly, seriously restricting its application in projects that need to serve for a long time.

[0004] At present, the durability of jute fabric is mainly improved through two ways: (1) Asphalt coating treatment. Although traditional asphalt can form a physical barrier to delay degradation, its construction requires high-temperature heating, with complex operation and high energy consumption. At the same time, local failure may occur due to uneven coating. (2) Chemical modification treatment: For example, impregnation with antibacterial agents (such as benzothiazole compounds) or composite resins can effectively inhibit biodegradation, but the chemical reagents have the problems of high cost and poor environmental compatibility; in addition, chemical treatment may also reduce the flexibility of jute fiber and affect its synergistic effect with soil. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a multi-layer jute geotextile modified by asphalt emulsion, its preparation method and application to solve the above problems.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] The present invention provides a preparation method of a multi-layer jute geotextile modified by asphalt emulsion, and the method includes the following steps.

[0008] S1. Disperse nano-silica in water to form a nano-material dispersion liquid.

[0009] S2. Add an emulsifier and a stabilizer to water, heat and stir, and then adjust the pH value of the solution to acidic with hydrochloric acid to obtain a soap solution.

[0010] S3. Heat the base asphalt and pour it into the asphalt tank. Turn on the internal circulation system of the asphalt tank to disperse the molten asphalt into a homogeneous mass. Then pour the soap solution into the colloid mill, use the colloid mill for high-speed shearing, and then quickly cool it to room temperature to obtain emulsified asphalt.

[0011] S4. Mix the waterborne epoxy resin and alkaline silica sol evenly to obtain a composite latex.

[0012] S5. Add the composite latex to the emulsified asphalt, and use a high-speed shearing machine to shear and stir to fully mix the composite latex and the emulsified asphalt to obtain modified emulsified asphalt.

[0013] S6. Slowly add the nano-material dispersion liquid to the modified emulsified asphalt, and stir evenly to obtain a modified asphalt emulsion.

[0014] S7. Immerse the jute geotextile in the silane coupling agent solution to make the silane coupling agent evenly adhere to the surface of the jute fiber, and then take out the jute geotextile and dry it.

[0015] S8. Mix the natural rubber latex and petroleum resin emulsion in proportion to make a composite treatment solution. Immerse the dried jute geotextile in the composite treatment solution, take it out, dry it at room temperature and then continue to dry it to obtain a modified jute geotextile.

[0016] S9. Use a high-pressure airless spraying device to evenly cover the surface of the modified jute geotextile with the modified asphalt emulsion, and then reinforce it layer by layer to obtain a composite material.

[0017] S10. Compact the composite material with a dry density of 97% and a moisture content of 10.4%, and place the specimen in a constant temperature and humidity environment for 7 days to promote the cement hydration reaction to obtain the finished product.

[0018] Further, in the step S1, the nano-silica can be replaced by nano-zinc oxide; in the step S2, the emulsifier can be selected as lecithin, and the stabilizer can be selected as carboxymethyl cellulose and sewage calcium chloride; in the step S3, the base asphalt is RS-1 type asphalt emulsion.

[0019] Further, in the step S2, the stirring conditions after adding the emulsifier and the stabilizer to water are: stirring at 300 r / min for 20 - 30 min at 6 - 70 °C, and adjusting the pH value of the solution to 2 - 3 with hydrochloric acid;

[0020] In the step S3, the heating temperature of the base asphalt is 13 - 140 °C, and the rotation speed of the colloid mill is 9000 - 10000 r / min;

[0021] In the step S5, after mixing the composite latex and the emulsified asphalt, the shearing speed is 2000 - 3000 r / min, and the shearing time is 10 - 20 min;

[0022] In step S6, after the nano-material dispersion liquid is mixed with the modified emulsified asphalt, it is stirred at a rotation speed of 1000 - 2000 r / min for 10 - 15 min.

[0023] Furthermore, in step S7, the concentration of the silane coupling agent is 1 - 3%, and the soaking time is 10 - 20 min; the drying temperature of the jute geotextile is 80 - 100 °C;

[0024] In step S8, the mass ratio of the natural rubber latex to the petroleum resin emulsion is 1:1, the soaking time of the jute geotextile in the composite treatment liquid is 5 - 10 min, and the temperature for continued drying after air drying is 60 - 80 °C;

[0025] In step S10, the constant temperature and humidity environment is 24 °C, and the humidity ≥ 90%.

[0026] Furthermore, the spraying gradient of the modified asphalt emulsion on the modified jute geotextile is 0.6 kg / m 2 .

[0027] Furthermore, the multi-layer jute geotextile is applied to soil reinforcement and engineering protection in earthquake areas.

[0028] The beneficial effects of the present invention are as follows:

[0029] 1. In the present invention, adding nano-materials can improve the strength and stability of asphalt. The waterborne epoxy resin reacts with the emulsified asphalt to form a three-dimensional cross-linked network. The addition of silica sol further refines the particles of the emulsified asphalt, enhances the interaction between the particles, consolidates the strength of the asphalt matrix. The modified asphalt emulsion has remarkable adhesion and stability, shows higher compressive strength and shear strength after curing. At the same time, the microscopic porosity is optimized, reducing the water permeability, enhancing the waterproof performance, and improving the high-temperature and low-temperature resistance.

[0030] 2. In the present invention, the treatment with silane coupling agent can improve the chemical properties of the surface of jute fibers, enhance their compatibility and adhesion performance with the asphalt emulsion. The composite treatment of natural rubber latex and petroleum resin emulsion can form an elastic and tough film on the surface of the jute geotextile, enabling the jute geotextile to better disperse stress when subjected to external forces, improving the tensile strength and anti-deformation ability of the fabric. At the same time, it also helps to improve the adhesion strength between the jute geotextile and the modified asphalt emulsion, enabling the two to work better together and enhancing the soil reinforcement effect.

[0031] 3. Treatment with the modified asphalt emulsion of the present invention increases the tensile strength of jute geotextiles from 440 N (untreated) to 535 N, increases the elastic modulus by about 22%, and the double-layer embedding reduces the brittleness index (IB) by 11.36% (70 kPa confining pressure) to 15% (140 kPa confining pressure), avoiding sudden failure. Moreover, through multi-level stress transfer, the double-layer embedding structure controls the IB value within 0.34 - 0.39 (140 kPa confining pressure), breaking through the traditional single-layer brittleness bottleneck.

[0032] 4. Compared with traditional chemical treatment, the construction energy consumption of the modified asphalt emulsion of the present invention is reduced by 40% (no high-temperature equipment required); the composite material ratio reduces the cement dosage by 30%, and the comprehensive cost is reduced by 15% - 20%.

[0033] Other advantages, objectives, and features of the present invention will be described in the subsequent specification, and to some extent, they are obvious to those skilled in the art, or those skilled in the art can obtain teachings from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following specification. Brief Description of the Drawings

[0034] To make the objectives, technical solutions, and beneficial effects of the invention clearer, the present invention provides the following drawings for description:

[0035] Figure 1 A close-up view of untreated jute geotextiles;

[0036] Figure 2 For a jute geotextile treated at an application rate of 0.5 kg / m 2 A close-up view;

[0037] Figure 3 For a jute geotextile treated at an application rate of 0.6 kg / m 2 A close-up view;

[0038] Figure 4 A partial exposure SEM image of jute geotextiles;

[0039] Figure 5 A completely covered SEM image of jute geotextiles. Detailed Description of the Preferred Embodiments

[0040] As Figures 1-5 shown, the present invention provides a preparation method for a multi-layer jute geotextile based on asphalt emulsion modification.

[0041] S1. Add 5 parts of nano-silica to 50 parts of water, and through ultrasonic dispersion, uniformly disperse the nano-silica in the water to form a nano-material dispersion liquid;

[0042] S2. Add 6 parts of lecithin and 6 parts of carboxymethyl cellulose to 65 parts of water, heat to 35°C, stir at a speed of 300 r / min for 25 min, and at the same time adjust the pH value of the solution to 2.5 with industrial hydrochloric acid to obtain a soap solution;

[0043] S3. Heat 100 parts of RS-1 type asphalt emulsion to 135°C and transfer it to an asphalt tank. Set the rotation speed of the colloid mill to 9500 r / min, turn on the internal circulation system of the asphalt tank to disperse the molten asphalt into a homogeneous mass for 30 min. Then slowly add the soap solution to the colloid mill, start the colloid mill and shear at 9500 r / min for 3 min, and then quickly cool to room temperature to obtain emulsified asphalt;

[0044] S4. Mix 20 parts of waterborne epoxy resin and 12 parts of alkaline silica sol evenly to obtain a composite latex;

[0045] S5. Add the composite latex to the emulsified asphalt and use a high-speed shearer to shear at a speed of 2500 r / min for 15 min to fully mix the composite latex and the emulsified asphalt, ensuring that the modifier is evenly dispersed in the asphalt system to obtain modified emulsified asphalt;

[0046] S6. Slowly add the nano-material dispersion liquid to the modified emulsified asphalt, and continue to stir at a speed of 1500 r / min for 12.5 min to make the nano-materials evenly distributed in the modified emulsified asphalt to obtain a modified asphalt emulsion;

[0047] S7. Immerse the jute geotextile in a 2% silane coupling agent solution for 15 min to make the silane coupling agent evenly adhere to the surface of the jute fiber. Then take out the jute geotextile and dry it at 90°C to make the silane coupling agent react chemically with the jute fiber to improve the compatibility between the jute fiber and the asphalt emulsion;

[0048] S8. Mix 20 parts of natural latex and 20 parts of petroleum resin emulsion to make a composite treatment liquid. Immerse the dried jute geotextile in the composite treatment liquid for 8 min to make the composite treatment liquid fully penetrate into the fibers of the jute geotextile. Take it out and dry it at room temperature, and then dry it at 70°C to form a uniform film on the surface of the jute geotextile with the natural latex and the petroleum resin emulsion, further improving the strength and toughness of the jute geotextile and its bonding performance with the modified asphalt emulsion;

[0049] S9. Use a high-pressure airless spraying equipment to evenly cover the surface of the modified jute geotextile with the modified asphalt emulsion, and then reinforce it in layers. Place the treated fabric at 1 / 3 height of the specimen (the specimen is composed of soil, fly ash, and cement with a mass ratio of 71.2%:17.8%:10%), and utilize its high tensile strength to disperse the upper load. Set a double-layer fabric at 1 / 2 height, and reduce the risk of brittle fracture through multi-stage stress transfer to obtain a composite material;

[0050] S10. Compact the composite material at 97% of the maximum dry density and 10.4% of the optimum moisture content, and place the specimen in a constant temperature and humidity environment (24°C, humidity ≥ 90%) for 7 days to promote the cement hydration reaction to obtain the finished product.

[0051] The multi-layer jute geotextile is applied to soil reinforcement and engineering protection in seismic areas.

[0052] Examples 1 - 4

[0053] Treat the modified jute geotextile with different dosages of the modified asphalt emulsion.

[0054] The spraying gradients of Examples 1 - 4 are respectively: 0.4 kg / m 2 、0.5 kg / m 2 、0.6 kg / m 2 、0.7 kg / m 2 , and the remaining preparation steps are the same.

[0055] Bury the modified jute geotextile in compost (fertile soil:cow dung:sand = 2:1:1) for 21 days, and then conduct tests on the tensile strength retention rate, air permeability, and SEM analysis after degradation. The results show that the strength of the natural jute geotextile only loses 14.49%, far lower than the 83.81% strength loss of the untreated fabric, meeting the BIS standard (≤ 20%). Thus, it is determined that the precise application amount of 0.6 kg / m 2 is the optimal spraying amount, taking into account both anti-degradability and air permeability. The test results are shown in Table 1 below:

[0056] Table 1

[0057]

[0058] It can be seen from Table 1 that when the application amount is 0.6 kg / m 2 the effect is the best, taking into account both anti-degradability (retention rate ≥ 85.51%) and air permeability (≥ 12.8 L / m 2 / s); when the application amount ≥ 0.7 kg / m 2 , the air permeability decreases significantly, affecting the vegetation growth compatibility.

[0059] Examples 5 - 7

[0060] Comparative tests were conducted with different types of asphalt emulsions.

[0061] In Examples 5 - 7, RS1 type cationic asphalt emulsion and RS2 type anionic asphalt emulsion (from the same brand) were respectively selected; conventional hot melt asphalt (penetration 60), and the remaining preparation steps were the same. Comparative tests were carried out with a unified application rate of 0.6 kg / m 2 , and the spraying process and drying conditions were consistent.

[0062] The experimental results are shown in Table 2:

[0063] Table 2

[0064]

[0065] It can be seen from Table 2 that when the RS1 cationic emulsion of the present invention is selected, the best covering effect and degradation resistance are achieved under normal temperature construction, and the comprehensive performance is superior to that of the anionic emulsion; although the traditional hot melt asphalt has slightly better degradation resistance, it requires high-temperature construction, high energy consumption and is easy to damage jute fibers, so it is not suitable for ecological projects.

[0066] Examples 8 - 10

[0067] Comparative tests were carried out between the jute geotextiles treated with RS-1 type asphalt emulsion and traditional modification methods.

[0068] In Examples 8 - 10, the jute geotextiles treated with the modified asphalt emulsion of the present invention, traditional asphalt hot coating treatment, and benzothiazole chemical treatment (concentration 5%) were respectively used for comparative tests, and the test results are shown in Table 3:

[0069]

[0070] It can be seen from Table 3 that the jute geotextiles treated with the modified asphalt emulsion of the present invention are significantly superior to the traditional methods in terms of environmental compatibility (earthworm survival rate 98%) and flexibility (>5000 cycles); although the chemical treatment has a low cost, it has high ecological toxicity, which limits its application in sustainable engineering.

[0071] In summary, the following conclusions can be briefly drawn:

[0072] 1. For the jute geotextiles treated with 0.6 kg / m 2 modified asphalt emulsion, the strength loss after 21-day biodegradation is only 14.49%, far lower than 83.81% of the untreated fabric, meeting the BIS standard (≤20%), and significantly extending the service life.

[0073] 2. Double-layer embedded structure (1 / 3 - 1 / 2 height), the brittleness index (IB) decreases from 0.44 of the single layer (70 kPa confining pressure) to 0.39, and further decreases to 0.34 under 140 kPa confining pressure, effectively avoiding sudden brittle fracture, especially suitable for engineering in seismic areas.

[0074] 3. Using modified asphalt emulsion, no high-temperature heating is required, the energy consumption is reduced by 40%, and the pollution risk of chemical antibacterial agents is avoided, which conforms to the concept of green construction.

[0075] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A preparation method of a multi-layer jute geotextile modified by asphalt emulsion, characterized in that: The method includes the following steps: S1. Disperse nano-silica in water to form a nano-material dispersion liquid. S2. Add an emulsifier and a stabilizer to water, heat and stir while raising the temperature, and then adjust the pH value of the solution to acidic with hydrochloric acid to obtain a soap solution. S3. Heat the matrix asphalt and pour it into an asphalt tank. Turn on the internal circulation system of the asphalt tank to disperse the hot-melt asphalt into a homogeneous mass. Then pour the soap solution into a colloid mill, use the colloid mill for high-speed shearing, and then quickly cool it to room temperature to obtain emulsified asphalt. S4. Mix waterborne epoxy resin and alkaline silica sol evenly to obtain a composite latex. S5. Add the composite latex to the emulsified asphalt, and use a high-speed shearer to shear and stir to fully mix the composite latex and the emulsified asphalt to obtain modified emulsified asphalt. S6. Slowly add the nano-material dispersion liquid to the modified emulsified asphalt, and stir evenly to obtain a modified asphalt emulsion. S7. Immerse the jute geotextile in a silane coupling agent solution to make the silane coupling agent evenly adhere to the surface of the jute fiber, and then take out the jute geotextile and dry it. S8. Mix natural latex and petroleum resin emulsion in proportion to make a composite treatment liquid. Immerse the dried jute geotextile in the composite treatment liquid, take it out, air-dry it at room temperature and then continue to dry it to obtain a modified jute geotextile. S9. Use a high-pressure airless spraying device to evenly cover the surface of the modified jute geotextile with the modified asphalt emulsion, and then reinforce it in layers to obtain a composite material. S10. Compact the composite material with a dry density of 97% and a water content of 10.4%, and place the specimen in a constant temperature and humidity environment for 7 days to promote the cement hydration reaction to obtain a finished product.

2. The preparation method of a multi-layer jute geotextile modified based on asphalt emulsion according to claim 1, characterized in that: In the step S1, the nano-silica can be replaced by nano-zinc oxide; in the step S2, the emulsifier can be selected as lecithin, and the stabilizer can be selected as carboxymethyl cellulose and sewage calcium chloride; in the step S3, the matrix asphalt is RS-1 type asphalt emulsion.

3. A preparation method of a multi-layer jute geotextile modified based on asphalt emulsion according to claim 1, characterized in that: In the step S2, the stirring conditions after adding the emulsifier and the stabilizer to water are: stir at 300 r / min for 20 - 30 min at 6 - 70 °C, and adjust the pH value of the solution to 2 - 3 with hydrochloric acid. In the step S3, the heating temperature of the matrix asphalt is 130 - 140 °C, and the rotation speed of the colloid mill is 9000 - 10000 r / min. In the step S5, after mixing the composite latex and the emulsified asphalt, the shear speed is 2000 - 3000 r / min, and the shear time is 10 - 20 min. In the step S6, after mixing the nano-material dispersion liquid and the modified emulsified asphalt, stir at a rotation speed of 1000 - 2000 r / min for 10 - 15 min.

4. The preparation method of a multi-layer jute geotextile modified based on asphalt emulsion according to claim 1, characterized in that: In the step S7, the concentration of the silane coupling agent is 1 - 3%, and the soaking time is 10 - 20 min. The drying temperature of the jute geotextile is 80 - 100 °C. In the step S8, the mass ratio of the natural latex and the petroleum resin emulsion is 1:1, the soaking time of the jute geotextile in the composite treatment liquid is 5 - 10 min, and the drying temperature after air-drying and then continuing to dry is 60 - 80 °C. In the step S10, the constant temperature and humidity environment is 24 °C, and the humidity ≥ 90%.

5. The preparation method of a multi-layer jute geotextile modified based on asphalt emulsion according to claim 1, characterized in that: The spraying gradient of the modified asphalt emulsion on the modified jute geotextile is 0.6 kg / m 2 .

6. The multi-layer jute geotextile according to any one of claims 1-5 is applied to soil reinforcement and engineering protection in seismic areas.

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