Preparation method of high-adsorption wear-resistant bamboo fiber and application of high-adsorption wear-resistant bamboo fiber in asphalt mixture

Abstract

The invention belongs to the technical field of asphalt pavement materials, and particularly relates to a preparation method of high-adsorption wear-resistant bamboo fibers and application of the high-adsorption wear-resistant bamboo fibers in an asphalt mixture. The functional silane coupling agent is adopted to modify the bamboo fibers, so that the surfaces of the bamboo fibers become rougher, the contact area of the bamboo fibers and asphalt is increased, and adsorption of more asphalt is facilitated; besides, pyrazine rings grafted on the surfaces of the bamboo fibers have a conjugation effect and can improve affinity with asphalt with the conjugation effect, and thioether, hydrophobic dimethyl butyl, hydrophobic adamantane and hydrophilic quaternary ammonium salt grafted on the surfaces of the bamboo fibers can improve the surface activity and promote the asphalt to permeate into the bamboo fibers, so that the bamboo fibers are more stable in performance. The affinity adhesion between the bamboo fibers and the asphalt is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of asphalt pavement materials, and particularly relates to a preparation method of high-adsorption wear-resistant bamboo fiber and application of the high-adsorption wear-resistant bamboo fiber in asphalt mixture. BACKGROUND

[0002] Asphalt pavement has the advantages of no joint, smooth and comfortable automobile driving, low noise, high mechanical strength, and convenient maintenance and repair, and has become the main form of domestic and foreign high-grade pavement. However, with the rapid growth of traffic volume and the increase of large vehicles, the conventional asphalt pavement prematurely appears a large number of diseases, which damages the service performance and service life. Using modified asphalt or adding additional materials is a common method to improve the performance of asphalt mixture, and the fiber stabilizer is a typical additional material, which has the characteristics of easy material acquisition, simple adding method, and good performance improvement effect, and has been widely applied in asphalt pavement construction and maintenance engineering.

[0003] The fiber can effectively improve the overall performance of the asphalt mixture, so that it can bear heavy traffic load, heavy traffic volume and harsh environmental conditions, and expand the application range of the asphalt mixture. The fiber stabilizer added in the asphalt mixture mainly includes synthetic fiber, plant fiber and mineral fiber. Among them, the bamboo fiber belongs to green, environment-friendly and renewable resources, and has the characteristics of fast production cycle and short time. However, the compatibility and interfacial bonding capacity of the bamboo fiber with asphalt and aggregate are poor, and the bamboo fiber modified asphalt pavement will be damaged after a long time of vehicle load, high temperature, ultraviolet radiation, rain and freezing, which leads to the decline of the performance of the asphalt mixture pavement and shortens the service life. SUMMARY

[0004] In view of the above problems, the application provides a preparation method of high-adsorption wear-resistant bamboo fiber and application of the high-adsorption wear-resistant bamboo fiber in asphalt mixture, which is used to solve the problem of poor aging performance of the asphalt mixture caused by the poor compatibility and interfacial bonding capacity of the bamboo fiber with asphalt and aggregate.

[0005] To achieve the above purpose, the technical scheme adopted by the application is as follows:

[0006] A preparation method of high-adsorption wear-resistant bamboo fiber, comprising the following steps: mixing and reacting bamboo fiber and a functional silane coupling agent to obtain high-adsorption wear-resistant bamboo fiber, wherein the functional silane coupling agent is prepared by quaternary ammonium salt reaction of piperazine pyrazine grafted methoxysilane and 1-(2-bromoethyl)adamantane, and the chemical structure of the piperazine pyrazine grafted methoxysilane is as follows:

[0007] .

[0008] Preferably, the method for mixing and reacting the bamboo fibers and the functional silane coupling agent is as follows: heating the bamboo fibers, the functional silane coupling agent, water and ethanol to 85-95℃, and stirring for 9-12h.

[0009] Preferably, the mass ratio of the bamboo fibers, the functional silane coupling agent, water and ethanol is 2-3:4-6:30-40:60-70.

[0010] Preferably, the average diameter of the bamboo fibers is 20-30μm, and the average length is 2-6mm.

[0011] Preferably, the molar ratio of the piperazine pyrazine grafted methoxysilane and 1-(2-bromoethyl)adamantane is 1:4.2-4.5.

[0012] Preferably, the temperature of the quaternary ammonium salt reaction is 80-90℃, and the time is 7-10h.

[0013] Preferably, the method for preparing the piperazine pyrazine grafted methoxysilane is as follows: subjecting 1,3-dimethoxy-1,3-dimethyl-1,3-divinyl disiloxane and 1-(3,3-dimethylbutyl) piperazine to a Michael addition reaction to obtain an intermediate, and then subjecting the intermediate and 2-pyrazinylethanethiol to a Michael addition reaction to obtain the piperazine pyrazine grafted methoxysilane.

[0014] Preferably, the molar ratio of the 1,3-dimethoxy-1,3-dimethyl-1,3-divinyl disiloxane, 1-(3,3-dimethylbutyl) piperazine and 2-pyrazinylethanethiol is 1:1:1.

[0015] Preferably, the temperature of the Michael addition reaction of 1,3-dimethoxy-1,3-dimethyl-1,3-divinyl disiloxane and 1-(3,3-dimethylbutyl) piperazine is 75-80℃, and the time is 5-7h; the temperature of the Michael addition reaction of the intermediate and 2-pyrazinylethanethiol is 85-90℃, and the time is 6-8h.

[0016] The high adsorption and wear-resistant bamboo fiber prepared by the above method is applied in asphalt mixture.

[0017] The high adsorption and wear-resistant bamboo fiber prepared by the above method and the application thereof in asphalt mixture have the following advantages:

[0018] (1) The functional silane coupling agent is used for modifying the bamboo fiber in the application, so that the bamboo fiber surface becomes rougher, the contact area of the bamboo fiber and asphalt is increased, more asphalt can be adsorbed, in addition, the conjugate effect of the grafted pyrazine ring on the bamboo fiber surface can improve the affinity with asphalt with conjugate effect, and the surface activity of the grafted sulfide, hydrophobic dimethyl butyl, hydrophobic adamantane and hydrophilic quaternary ammonium salt on the bamboo fiber surface can be improved, the asphalt is promoted to penetrate into the bamboo fiber, and the oil absorption rate of the bamboo fiber is improved. Moreover, the high adsorption and wear-resistant bamboo fiber prepared by the application has a small water absorption rate, and can better resist water intrusion. Finally, the asphalt has good spreading property on the surface of the high adsorption and wear-resistant bamboo fiber prepared by the application, and has a larger contact area, which indicates that the interface combination of the high adsorption and wear-resistant bamboo fiber prepared by the application and asphalt is good. This is because the functional silane coupling agent can significantly improve the compatibility of the bamboo fiber and asphalt, and improve the adhesion between the bamboo fiber and asphalt.

[0019] (2) The high adsorption and wear-resistant bamboo fiber prepared by the application can effectively improve the modulus and deformation resistance of asphalt matrix. When the temperature is higher, the grafted piperazine quaternary ammonium salt and pyrazine quaternary ammonium salt on the surface of the high adsorption and wear-resistant bamboo fiber prepared by the application can form a fiber network structure through conjugate effect, physical crosslinking and mechanical intercalation, so as to enhance the deformation resistance of asphalt.

[0020] (3) The high-adsorption wear-resistant bamboo fiber prepared by the application has a low flying loss rate, which is due to the low water absorption rate of the high-adsorption wear-resistant bamboo fiber, which can reduce the penetration of water into the asphalt mixture interface, avoid the shedding of the asphalt film, enhance the bonding force between the asphalt, the fiber and the mineral aggregate, reduce the shedding, particle dropping and flying loss rate of the asphalt mixture, and improve the safe operation level of the asphalt pavement. The high-adsorption wear-resistant bamboo fiber prepared by the application has a low construction depth reduction rate and a low deflection value reduction rate, which proves that the high-adsorption wear-resistant bamboo fiber prepared by the application can effectively improve the wear resistance of the asphalt mixture and improve the integrity of the asphalt film, which is due to the hydrophilic and hydrophobic functional groups on the surface of the high-adsorption wear-resistant bamboo fiber and the good surface activity, which can effectively improve the dispersion uniformity of the solid filler in the asphalt mixture, avoid the agglomeration of the solid filler, tightly bind the solid filler in the network dense structure formed by the physical crosslinking and mechanical embedding of the high-adsorption wear-resistant bamboo fiber and the asphalt, avoid the wear of the solid filler, and further improve the wear resistance and skid resistance of the asphalt mixture. In addition, the asphalt mixture corresponding to the high-adsorption wear-resistant bamboo fiber prepared by the application has high tensile strength and bending strain, which shows that the high-adsorption wear-resistant bamboo fiber in the mixture can form a network dense structure through physical winding and mechanical embedding, improve the load damage resistance of the mixture, and the surface of the high-adsorption wear-resistant bamboo fiber has strong surface activity, can be uniformly dispersed in the asphalt mixture, better play the role of reinforcement and bridging, and further improve the flexibility of the mixture. The asphalt mixture corresponding to the high-adsorption wear-resistant bamboo fiber prepared by the application has high dynamic stability, which is due to the fact that the high-adsorption wear-resistant bamboo fiber can effectively absorb the light components of the asphalt after being uniformly dispersed in the asphalt mixture, improve the viscosity of the mixture, make it not easy to soften at high temperature, and the high-adsorption wear-resistant bamboo fiber can form a three-dimensional network structure in the asphalt mixture, effectively limit the movement of the mineral aggregate, and improve the high-temperature deformation resistance of the mixture. Finally, the asphalt mixture corresponding to the high-adsorption wear-resistant bamboo fiber prepared by the application has better aging resistance, and after aging for a long time at high temperature, the asphalt mixture still shows good mechanical properties, low-temperature performance, high-temperature performance and water resistance, which proves that the high-adsorption wear-resistant bamboo fiber prepared by the application can effectively improve the service life of the asphalt mixture and meet the use requirements of heavy traffic pavement. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 NMR spectrum of the piperazine pyrazine grafted methoxysilane prepared in the examples. DETAILED DESCRIPTION

[0022] In order for those skilled in the art to better understand the technical solutions, the application will be described in detail below in conjunction with the examples, and the description in this part is only exemplary and explanatory, and should not have any limiting effect on the protection scope of the application.

[0023] Example 1

[0024] The preparation method of the high-adsorption wear-resistant bamboo fiber of the embodiment comprises the following steps:

[0025] (1) 1,3-dimethoxy-1,3-dimethyl-1,3-divinyl disiloxane, 1-(3,3-dimethylbutyl) piperazine, triethylamine and anhydrous toluene with a molar ratio of 1:1:0.03:6 are added into a reaction kettle, heated to 75°C, and stirred for 5h, then 2-pyrazinylethanethiol (the molar ratio of 2-pyrazinylethanethiol to 1,3-dimethoxy-1,3-dimethyl-1,3-divinyl disiloxane is 1:1) is added, heated to 90°C, and stirred for 6h, then triethylamine and toluene are removed by distillation under reduced pressure to obtain a crude product, the crude product is purified by column chromatography using a mixed solvent of petroleum ether, ethyl acetate and dichloromethane with a volume ratio of 4:5:1 to obtain piperazine pyrazine grafted methoxysilane; the proton nuclear magnetic resonance spectrum of the piperazine pyrazine grafted methoxysilane is as shown in Figure 1 , and the chemical structure is as follows:

[0026] .

[0027] (2) Piperazine pyrazine grafted methoxysilane, 1-(2-bromoethyl)adamantane and anhydrous toluene with a molar ratio of 1:4.2:9 are added into a reaction kettle, heated to 80°C, and stirred for 7h, then toluene and unreacted 1-(2-bromoethyl)adamantane are removed by distillation under reduced pressure to obtain a functional silane coupling agent; the chemical structure of the functional silane coupling agent is as follows:

[0028] .

[0029] (3) Bamboo fiber (with an average diameter of 20μm and an average length of 2mm), the functional silane coupling agent, deionized water and ethanol with a mass ratio of 2:4:30:60 are added into a stirring kettle, uniformly stirred, heated to 85°C, and stirred for reflux reaction for 9h, then filtered after cooling to room temperature, the filter cake is washed with ethanol, and dried to obtain the high-adsorption wear-resistant bamboo fiber.

[0030] Example 2

[0031] The preparation method of the high-adsorption wear-resistant bamboo fiber of the embodiment comprises the following steps:

[0032] (1) 1,3-dimethoxy-1,3-dimethyl-1,3-divinyl disiloxane, 1-(3,3-dimethylbutyl) piperazine, triethylamine and anhydrous toluene with a molar ratio of 1:1:0.04:7 were added into a reaction kettle, heated to 78°C, stirred for 6h, then 2-pyrazinylethanethiol (the molar ratio of 2-pyrazinylethanethiol and 1,3-dimethoxy-1,3-dimethyl-1,3-divinyl disiloxane was 1:1) was added, heated to 88°C, and the stirring reaction was continued for 7h. After that, triethylamine and toluene were removed by distillation under reduced pressure to obtain a crude product. The crude product was purified by column chromatography using a mixed solvent of petroleum ether, ethyl acetate and dichloromethane with a volume ratio of 4:5:1 to obtain piperazine pyrazine grafted methoxysilane. The chemical structure of the piperazine pyrazine grafted methoxysilane is as follows:

[0033] .

[0034] (2) Piperazine pyrazine grafted methoxysilane, 1-(2-bromoethyl)adamantane and anhydrous toluene with a molar ratio of 1:4.3:11 were added into a reaction kettle, heated to 85°C, stirred for 9h, and then toluene and unreacted 1-(2-bromoethyl)adamantane were removed by distillation under reduced pressure to obtain a functional silane coupling agent. The chemical structure of the functional silane coupling agent is as follows:

[0035] .

[0036] (3) Bamboo fibers (with an average diameter of 25μm and an average length of 4mm), the functional silane coupling agent, deionized water and ethanol with a mass ratio of 3:5:35:65 were added into a stirring kettle, stirred uniformly, heated to 88°C, and then stirred for 10h under reflux. After cooling to room temperature, the mixture was filtered, the filter cake was washed with ethanol, and then dried to obtain high-adsorption and wear-resistant bamboo fibers.

[0037] Example 3

[0038] The preparation method of the high-adsorption and wear-resistant bamboo fibers of the present embodiment comprises the following steps:

[0039] (1) 1,3-dimethoxy-1,3-dimethyl-1,3-divinyl disiloxane, 1-(3,3-dimethylbutyl) piperazine, triethylamine and anhydrous toluene in a molar ratio of 1:1:0.05:9 were added into a reaction kettle, heated to 80°C, stirred for 7h, then 2-pyrazinylethanethiol (the molar ratio of 2-pyrazinylethanethiol to 1,3-dimethoxy-1,3-dimethyl-1,3-divinyl disiloxane was 1:1) was added, heated to 85°C, and the stirring reaction was continued for 8h. After that, triethylamine and toluene were removed by distillation under reduced pressure to obtain a crude product. The crude product was purified by column chromatography using a mixed solvent of petroleum ether, ethyl acetate and dichloromethane in a volume ratio of 4:5:1 to obtain piperazine pyrazine grafted methoxysilane. The chemical structure of the piperazine pyrazine grafted methoxysilane is as follows:

[0040] .

[0041] (2) Piperazine pyrazine grafted methoxysilane, 1-(2-bromoethyl)adamantane and anhydrous toluene in a molar ratio of 1:4.5:12 were added into a reaction kettle, heated to 90°C, stirred for 10h, and then toluene and unreacted 1-(2-bromoethyl)adamantane were removed by distillation under reduced pressure to obtain a functional silane coupling agent. The chemical structure of the functional silane coupling agent is as follows:

[0042] .

[0043] (3) Bamboo fibers (average diameter of 30μm and average length of 6mm), the functional silane coupling agent, deionized water and ethanol in a mass ratio of 3:6:40:70 were added into a stirring kettle, stirred uniformly, heated to 95°C, and stirred for reflux reaction for 12h. After cooling to room temperature, the mixture was filtered, the filter cake was washed with ethanol, and then dried to obtain high-adsorption wear-resistant bamboo fibers.

[0044] Comparative Example 1

[0045] The difference between the preparation method of the high-adsorption wear-resistant bamboo fibers of the present comparative example and the preparation method of the high-adsorption wear-resistant bamboo fibers of Example 1 is that 1-(3,3-dimethylbutyl) piperazine in step (1) of the preparation method of the high-adsorption wear-resistant bamboo fibers of the present comparative example is replaced by 1-(2-cyclohexylethyl) piperazine.

[0046] Comparative Example 2

[0047] The difference between the preparation method of the high-adsorption wear-resistant bamboo fibers of the present comparative example and the preparation method of the high-adsorption wear-resistant bamboo fibers of Example 1 is that 1-(3,3-dimethylbutyl) piperazine in step (1) of the preparation method of the high-adsorption wear-resistant bamboo fibers of the present comparative example is replaced by N-tert-butyl piperazine.

[0048] Comparative Example 3

[0049] The preparation method of the high-adsorption wear-resistant bamboo fiber of the present comparative example is only different from the preparation method of the high-adsorption wear-resistant bamboo fiber of Example 1 in that 2-pyridine ethanethiol is used instead of 2-pyrazinyl ethanethiol in step (1) of the preparation method of the high-adsorption wear-resistant bamboo fiber of the present comparative example.

[0050] Comparative Example 4

[0051] The preparation method of the high-adsorption wear-resistant bamboo fiber of the present comparative example is only different from the preparation method of the high-adsorption wear-resistant bamboo fiber of Example 1 in that 2-pyridine ethanethiol is used instead of 2-pyrazinyl ethanethiol in step (1) of the preparation method of the high-adsorption wear-resistant bamboo fiber of the present comparative example.

[0052] Comparative Example 5

[0053] The preparation method of the high-adsorption wear-resistant bamboo fiber of the present comparative example is only different from the preparation method of the high-adsorption wear-resistant bamboo fiber of Example 1 in that 2-pyridine ethanethiol is used instead of 2-pyrazinyl ethanethiol in step (1) of the preparation method of the high-adsorption wear-resistant bamboo fiber of the present comparative example.

[0054] (1) The reaction kettle is added with vinyltrimethoxysilane, 1-(3,3-dimethylbutyl) piperazine, triethylamine and anhydrous toluene in a molar ratio of 1:1:0.03:6, heated to 75°C, stirred for 5h, and distilled under reduced pressure to remove triethylamine and toluene to obtain piperazine grafted methoxysilane.

[0055] (2) The reaction kettle is added with piperazine grafted methoxysilane, 1-(2-bromoethyl)adamantane and anhydrous toluene in a molar ratio of 1:2.2:9, heated to 80°C, stirred for 7h, and distilled under reduced pressure to remove toluene to obtain piperazine grafted methoxysilane quaternary ammonium salt.

[0056] (3) The reaction kettle is added with vinyltrimethoxysilane, 2-pyrazinyl ethanethiol, triethylamine and anhydrous toluene in a molar ratio of 1:1:0.03:6, heated to 75°C, stirred for 6h, and distilled under reduced pressure to remove triethylamine and toluene to obtain pyrazine grafted methoxysilane.

[0057] (4) The reaction kettle is added with pyrazine grafted methoxysilane, 1-(2-bromoethyl)adamantane and anhydrous toluene in a molar ratio of 1:2.2:9, heated to 80°C, stirred for 7h, and distilled under reduced pressure to remove toluene to obtain pyrazine grafted methoxysilane quaternary ammonium salt.

[0058] (5) The piperazine grafted methoxysilane quaternary ammonium salt and the pyrazine grafted methoxysilane quaternary ammonium salt are uniformly stirred in a molar ratio of 1:1 to obtain a functional silane coupling agent.

[0059] Comparative Example 6

[0060] The difference between the preparation method of the high-adsorption wear-resistant bamboo fiber of the present comparative example and the preparation method of the high-adsorption wear-resistant bamboo fiber of example 1 is that the functional silane coupling agent is replaced by methacryloxypropyl trimethoxysilane in step (3) of the preparation method of the high-adsorption wear-resistant bamboo fiber of the present comparative example.

[0061] Experimental example 1

[0062] The present experimental example is used to test the oil absorption rate, water content, and contact angle between the high-adsorption wear-resistant bamboo fiber prepared by each example and comparative example and asphalt. The oil absorption rate and water content are tested according to the provisions in standard JT / T 533-2016 “Lignin fiber for asphalt pavement”, the oil phase during testing is asphalt, and the contact angle between the high-adsorption wear-resistant bamboo fiber and asphalt is tested by the sessile drop method. The oil absorption rate, water content, and contact angle between the high-adsorption wear-resistant bamboo fiber prepared by each example and comparative example and asphalt are shown in Table 1.

[0063] Table 1 Oil absorption rate, water content, and contact angle between the high-adsorption wear-resistant bamboo fiber prepared by each example and comparative example and asphalt

[0064]

[0065]

[0066] From Table 1, it can be seen that the high-adsorption wear-resistant bamboo fiber prepared by examples 1-3 has a higher oil absorption rate. This is because the bamboo fiber is modified by the functional silane coupling agent, the micro-morphology is significantly changed, the bamboo fiber surface becomes rougher, the contact area between the bamboo fiber and asphalt is increased, which is beneficial to adsorb more asphalt. In addition, the pyrazine ring grafted on the surface of the bamboo fiber has a conjugation effect, which can improve the affinity with asphalt having a conjugation effect. Moreover, the sulfide, hydrophobic dimethyl butyl, hydrophobic adamantane, and hydrophilic quaternary ammonium salt grafted on the surface of the bamboo fiber can improve the surface activity, promote the penetration of asphalt into the bamboo fiber, and improve the oil absorption rate of the bamboo fiber. In addition, the high-adsorption wear-resistant bamboo fiber prepared by examples 1-3 has a smaller water content, which proves that the high-adsorption wear-resistant bamboo fiber prepared by the present application has a better ability to resist water intrusion. Finally, the asphalt has good spreading property on the surface of the high-adsorption wear-resistant bamboo fiber prepared by examples 1-3, and has a larger contact area, which indicates that the interface between the high-adsorption wear-resistant bamboo fiber prepared by the present application and asphalt is well combined. This is because the functional silane coupling agent can significantly improve the compatibility of the bamboo fiber and asphalt, and improve the adhesion between the bamboo fiber and asphalt.

[0067] Experimental example 2

[0068] ​The present experimental example is used to test the influence of the high-adsorption wear-resistant bamboo fibers prepared in Examples 1-3 and Comparative Examples 1-6 on the performance of fiber asphalt mortar. The fiber asphalt mortar is prepared as follows: the SBS modified asphalt is heated to 165℃, then the high-adsorption wear-resistant bamboo fibers are added, the mass of the high-adsorption wear-resistant bamboo fibers is 1.2% of the mass of the SBS modified asphalt, and the fiber asphalt mortar is obtained after uniform stirring. Then, the complex shear modulus of the fiber asphalt mortar is determined according to the standard T315-04 "Rheological Properties of Asphalt Binders Measured Using a Dynamic Shear Rheometer (DSR)", and the dynamic shear rheometer is used for testing, the experimental temperature is 50℃, 60℃ and 70℃, the scanning frequency is 10Hz, and the test results are shown in Table 2.

[0069] Table 2 Complex shear modulus of fiber asphalt mortar prepared by high-adsorption wear-resistant bamboo fibers prepared in Examples 1-3 and Comparative Examples 1-6

[0070] Table 2 Complex shear modulus of fiber asphalt mortar prepared by high-adsorption wear-resistant bamboo fibers prepared in Examples 1-3 and Comparative Examples 1-6

[0071]

[0072] As shown in Table 2, the fiber asphalt mortar prepared by the high-adsorption wear-resistant bamboo fibers prepared in the present application has a relatively high complex shear modulus at different temperatures, and the complex shear modulus decreases with the increase of temperature, but the complex shear modulus is higher than that of the high-adsorption wear-resistant bamboo fibers prepared in Comparative Example 1-6, which indicates that the high-adsorption wear-resistant bamboo fibers prepared in the present application can effectively improve the modulus and anti-deformation ability of the asphalt matrix. At a relatively high temperature, the piperazine quaternary ammonium salt and the pyrazine quaternary ammonium salt grafted on the surface of the high-adsorption wear-resistant bamboo fibers in the present application can form a fiber network structure through conjugation effect, physical crosslinking effect and mechanical intercalation effect, thereby enhancing the anti-deformation ability of the asphalt.

[0073] Application Example

[0074] In order to evaluate the practical application effect of high adsorption wear-resistant bamboo fibers prepared in Examples 1-3 and Comparative Examples 1-6 in asphalt mixture, SMA-13 mixture was taken as the test object, and the influence of high adsorption wear-resistant bamboo fibers on the performance of asphalt mixture was studied. The asphalt binder was SBS modified asphalt, the coarse aggregate was basalt stone, the fine aggregate was limestone chips, the mineral powder was fine limestone powder, the oil-stone ratio of the asphalt mixture was 5.1%, and the content of the high adsorption wear-resistant bamboo fibers was 0.5%. The dry method was used to mix the fiber asphalt mixture, first the mineral aggregate and the fiber were dry mixed with the mixer for 90s, then the asphalt was added and mixed for 90s, and finally the mineral powder was added and mixed for 90s. Then the water immersion flying test and the wheel type accelerated pavement tester were used to test the bonding force between the asphalt and the mineral aggregate in the asphalt mixture, the construction depth reduction rate and the deflection value reduction rate of the asphalt mixture, and then the uniaxial compression test, the low temperature bending test, the Marshall stability test, the water immersion Marshall test and the freeze-thaw splitting test were used to evaluate the mechanical properties, the low temperature performance, the high temperature performance and the water resistance of the asphalt mixture aged at 80℃ for 0h, 60h and 180h respectively.

[0075] In the water immersion flying test, the test was carried out according to the provisions in the standard T0733-2000 "Asphalt Mixture Flying Test"; the test methods of the construction depth reduction rate and the deflection value reduction rate were as follows: the asphalt mixture was made into anti-skid test piece plate, then the initial deflection value and the initial construction depth of the anti-skid test piece plate were measured by the pendulum method and the sand laying method, then the anti-skid test piece plate was subjected to abrasion experiment under a certain load by the wheel type accelerated pavement tester, when the abrasion times reached 20,000 times, the final deflection value and the final construction depth of the anti-skid test piece plate after the abrasion experiment were measured by the pendulum method and the sand laying method, the reduction rate of the final deflection value relative to the initial deflection value was calculated, which was the deflection value reduction rate, and the reduction rate of the final construction depth relative to the initial construction depth was calculated, which was the construction depth reduction rate; the uniaxial compression test was carried out according to the provisions in the standard T0713-2000 "Uniaxial Compression Test of Asphalt Mixture", the temperature during the test was 20℃, and the loading rate was 2mm / min; the low temperature bending test was carried out according to the provisions in the standard T0715-2000 "Bending Test of Asphalt Mixture", the temperature during the test was -10℃, and the loading rate was 50mm / min; the Marshall stability test was carried out according to the provisions in the standard T0709-2000 "Marshall Stability Test of Asphalt Mixture". The water immersion flying test (flying loss rate), the construction depth reduction rate, the deflection value reduction rate, the uniaxial compression test (compressive strength), the low temperature bending test (maximum bending tensile strain) and the Marshall stability test (dynamic stability) results of the high adsorption wear-resistant bamboo fibers prepared in Examples 1-3 and Comparative Examples 1-6 were shown in Table 3.

[0076] Table 3 Water immersion flying test, construction depth reduction rate, deflection value reduction rate, uniaxial compression test, low temperature bending test and Marshall stability test results of high adsorption wear-resistant bamboo fibers

[0077] Results of the rate of drop, uniaxial compression test, low-temperature bending test, and Marshall stability test

[0078]

[0079] As can be seen from Table 3, the high-adsorption wear-resistant bamboo fiber prepared in the application has a lower flying loss rate, which is because the high-adsorption wear-resistant bamboo fiber has a lower water absorption rate, can reduce the penetration of water into the interface of the asphalt mixture, avoid the shedding of the asphalt film, enhance the bonding force between the asphalt, the fiber and the mineral aggregate, reduce the shedding, particle loss and flying loss rate of the asphalt mixture, and improve the safe operation level of the asphalt pavement. The high-adsorption wear-resistant bamboo fiber prepared in the application has a lower construction depth reduction rate and a lower deflection value reduction rate, which proves that the high-adsorption wear-resistant bamboo fiber prepared in the application can effectively improve the wear resistance of the asphalt mixture and improve the integrity of the asphalt film, which is because the high-adsorption wear-resistant bamboo fiber has hydrophilic and hydrophobic functional groups on the surface and good surface activity, can effectively improve the dispersion uniformity of the solid filler in the asphalt mixture, avoid the agglomeration of the solid filler, make the solid filler tightly bound and fastened in the network dense structure formed by the physical crosslinking and mechanical embedding of the high-adsorption wear-resistant bamboo fiber and the asphalt, avoid the wear of the solid filler, and further improve the wear resistance and skid resistance of the asphalt mixture. In addition, the asphalt mixture corresponding to the high-adsorption wear-resistant bamboo fiber prepared in the application has a higher tensile strength and bending strain, which indicates that the high-adsorption wear-resistant bamboo fiber in the mixture can form a network dense structure through physical winding and mechanical embedding, improve the load damage resistance of the mixture, and the high-adsorption wear-resistant bamboo fiber has strong surface activity on the surface, can be uniformly dispersed in the asphalt mixture, better play the role of reinforcement and bridging, and further improve the flexibility of the mixture. The asphalt mixture corresponding to the high-adsorption wear-resistant bamboo fiber prepared in the application has a higher dynamic stability, which is because the high-adsorption wear-resistant bamboo fiber can effectively absorb the light components of the asphalt after being uniformly dispersed in the asphalt mixture, improve the viscosity of the mixture, make it not easy to soften at high temperature, and the high-adsorption wear-resistant bamboo fiber can form a three-dimensional network structure in the asphalt mixture, effectively limit the movement of the mineral aggregate, and improve the high-temperature deformation resistance of the mixture. Finally, compared with Comparative Examples 1-6, the asphalt mixture corresponding to the high-adsorption wear-resistant bamboo fiber prepared in the application has better anti-aging performance, and after aging at high temperature for a long time, the asphalt mixture still shows good mechanical properties, low-temperature performance, high-temperature performance and water resistance, which proves that the high-adsorption wear-resistant bamboo fiber prepared in the application can effectively improve the service life of the asphalt mixture and meet the use requirements of heavy traffic pavement.

[0080] From the example 1 and the comparative examples 1-2, it can be seen that when 1-(3,3-dimethylbutyl) piperazine is replaced by 1-(2-cyclohexylethyl) piperazine or N-tert-butyl piperazine, due to the large steric hindrance of cyclohexyl and tert-butyl, the cyclohexyl or tert-butyl grafted on the surface of the high-adsorption wear-resistant bamboo fiber is not conducive to penetrating into the asphalt matrix, and the combination tightness between the aggregate and the mineral powder and the high-adsorption wear-resistant bamboo fiber is reduced due to the too large steric hindrance, the binding fastness of the aggregate and the mineral powder in the asphalt mixture is reduced, and the comprehensive performance of the asphalt mixture is reduced.

[0081] From the example 1 and the comparative example 3, it can be seen that when 2-pyrazinylethanethiol is replaced by 2-pyridineethanethiol, the number of quaternary ammonium salt in the functional silane coupling agent is reduced and the parent structure of the quaternary ammonium salt is changed, which causes the surface activity and the conjugation property of the high-adsorption wear-resistant bamboo fiber to change, the affinity between the high-adsorption wear-resistant bamboo fiber and the asphalt and the aggregate and the mineral powder is reduced, and the dispersion degree of the high-adsorption wear-resistant bamboo fiber in the asphalt is weakened, thereby affecting the comprehensive performance of the asphalt mixture.

[0082] From the example 1 and the comparative example 4, it can be seen that when 1-(2-bromoethyl)adamantane is replaced by 2-bromoethylcyclohexane, although the cyclohexyl also has a certain steric hindrance, the lipophilicity is weak, and the physical cross-linking and mechanical embedding effect formed is small, which causes the affinity between the high-adsorption wear-resistant bamboo fiber and the asphalt, the combination ability of the interface to be reduced, and the binding fastness of the aggregate and the mineral powder in the asphalt mixture to be affected, thereby causing the comprehensive performance of the asphalt mixture to be reduced.

[0083] From the example 1 and the comparative example 5, it can be seen that when the piperazine grafted methoxysilane quaternary ammonium salt and the pyrazine grafted methoxysilane quaternary ammonium salt are used to modify the bamboo fiber, due to the poor uniformity of the piperazine quaternary ammonium salt and the pyrazine quaternary ammonium salt grafted on the surface of the bamboo fiber, the matching of the two quaternary ammonium salts is poor, the physical cross-linking and mechanical embedding effect of the grafted chains on the surface of the bamboo fiber is reduced, and the comprehensive performance of the asphalt mixture is reduced.

[0084] From the example 1 and the comparative example 6, it can be seen that when the conventional methacryloyloxypropyltrimethoxysilane is used to modify the bamboo fiber, the wear resistance, the mechanical property, the low-temperature performance, the high-temperature performance and the water resistance of the prepared asphalt mixture are all poor, which again proves that after the bamboo fiber is modified by the functional silane coupling agent synthesized in the application, the high-adsorption wear-resistant bamboo fiber can effectively improve the dispersion uniformity of the solid filler in the asphalt mixture, form a network dense structure through physical winding and mechanical embedding, improve the mechanical property of the mixture, and improve the flexibility of the asphalt mixture through the effects of reinforcement and bridging.

[0085] It should be noted that in this text, the terms: including, containing and any other variants are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. The principles and embodiments of the technical solutions of the present application are described by applying specific examples. The above example is only used to help understand the method of the present application and its core idea. The above is only the preferred embodiment of the present application. It should be noted that due to the limitation of language expression, there are infinite specific structures objectively. For ordinary skilled persons in the art, without departing from the principles of the present application, some improvements, refinements or changes can be made, and the above technical features can be combined in a proper way; these improvements, refinements, changes or combinations, or without improvement, the concept and technical solutions of the present application are directly applied to other occasions, which should be regarded as the protection scope of the present application.

Claims

1. A process for the preparation of high adsorptive wear resistant bamboo fiber characterized by, The method comprises the following steps: The bamboo fiber and the functional silane coupling agent are mixed and reacted to obtain high-adsorption wear-resistant bamboo fiber, wherein the functional silane coupling agent is prepared by quaternary ammonium salt reaction of piperazine pyrazine grafted methoxysilane and 1-(2-bromoethyl)adamantane, and the chemical structure of the piperazine pyrazine grafted methoxysilane is as follows: 。 2. The process for the preparation of high adsorbent wear resistant bamboo fibre as claimed in claim 1 wherein, The bamboo fiber, the functional silane coupling agent, water and ethanol are heated to 85-95 DEG C, and then stirred and reacted for 9-12 h.

3. The method for preparing highly adsorbent and wear-resistant bamboo fiber according to claim 2, characterized in that, The mass ratio of the bamboo fiber, the functional silane coupling agent, water and ethanol is 2-3:4-6:30-40:60-70.

4. The process for the preparation of high adsorbent wear resistant bamboo fiber as claimed in claim 2 wherein, The average diameter of the bamboo fiber is 20-30 mu m, and the average length is 2-6 mm.

5. The process for the preparation of high adsorbent wear resistant bamboo fiber as claimed in claim 1 wherein, The molar ratio of the piperazine pyrazine grafted methoxysilane and 1-(2-bromoethyl)adamantane is 1:4.2-4.

5.

6. The method of claim 1, wherein the high adsorptive wear resistant bamboo fiber is characterized by, The temperature of the quaternary ammonium salt reaction is 80-90 DEG C, and the time is 7-10 h.

7. The method of making high adsorbent wear resistant bamboo fiber according to any one of claims 1-6, wherein, The preparation method of the piperazine pyrazine grafted methoxysilane is as follows: 1,3-dimethoxy-1,3-dimethyl-1,3-divinyl disiloxane and 1-(3,3-dimethylbutyl) piperazine are subjected to Michael addition reaction to obtain an intermediate, and then the intermediate and 2-pyrazinyl ethanethiol are subjected to Michael addition reaction to obtain the piperazine pyrazine grafted methoxysilane.

8. The method for preparing highly adsorbent and wear-resistant bamboo fiber according to claim 7, characterized in that, The molar ratio of the 1,3-dimethoxy-1,3-dimethyl-1,3-divinyl disiloxane, 1-(3,3-dimethylbutyl) piperazine and 2-pyrazinyl ethanethiol is 1:1:

1.

9. The method for preparing highly adsorbent and wear-resistant bamboo fiber according to claim 7, characterized in that, The temperature of the Michael addition reaction of the 1,3-dimethoxy-1,3-dimethyl-1,3-divinyl disiloxane and 1-(3,3-dimethylbutyl) piperazine is 75-80 DEG C, and the time is 5-7 h; the temperature of the Michael addition reaction of the intermediate and 2-pyrazinyl ethanethiol is 85-90 DEG C, and the time is 6-8 h.

10. The application of high-adsorption wear-resistant bamboo fiber prepared by the method of any one of claims 1-9 in asphalt mixture.

Images