High-toughness hot-mixed regenerated epoxy asphalt

Abstract

The invention relates to the technical field of road engineering materials, and discloses high-toughness hot-mixed regenerated epoxy asphalt, which is prepared by the following steps: based on an epoxy ring-opening mechanism, taking trimethyl citrate, glycidyl methacrylate and 3-(2, 3-epoxypropoxy) propyltrimethoxysilane as raw materials to prepare an alkenyl trimethyl citrate silane coupling agent; the preparation method comprises the following steps: based on an esterification reaction mechanism, preparing an alkenylated trimethyl citrate silane coupling agent with a hindered phenol group by taking an alkenylated trimethyl citrate silane coupling agent and 3, 5-di-tert-butyl-4-hydroxybenzoic acid as raw materials; and modifying the nano titanium dioxide by using the modified nano titanium dioxide, and finally carrying out hydrolysis reaction to prepare the compatibilization type organic-inorganic composite anti-aging component. The high-toughness hot-mixed regenerated epoxy asphalt is prepared by taking an old asphalt mixture, epoxy resin, a compatibilization type organic-inorganic composite anti-aging component and the like as raw materials through mixing and hot mixing treatment. The epoxy asphalt prepared by the invention has excellent properties of high toughness, reproducibility, compatibility and aging resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of road engineering materials, and particularly relates to a high-toughness hot-mixing regenerated epoxy asphalt. BACKGROUND

[0002] In recent years, with the increase of traffic volume and the improvement of vehicle load, the traditional asphalt pavement is prone to cracking, rutting and other diseases, resulting in the shortening of the service life of the pavement. Epoxy asphalt gradually becomes an important material for high-grade pavement paving due to its excellent mechanical properties and durability. Among them, the hot-mixing epoxy asphalt mixture avoids the influence of the poor performance of the mixture caused by excessive water content of the aggregate, and has the advantages of easy control, simple construction, relatively short curing time and the like.

[0003] However, the existing epoxy asphalt material has technical bottlenecks in the aspect of recycling, and it is difficult to meet the needs of environmental protection and resource conservation. At present, the researches at home and abroad mainly focus on the optimization of the formula of epoxy asphalt and the improvement of the construction process, but the research on the high toughness and hot-mixing performance of regenerated epoxy asphalt is still in the initial stage. In addition, the compatibility of epoxy resin and asphalt is poor, and the traditional hot-mixing epoxy asphalt is prone to phase separation at high temperature, resulting in the decline of the construction performance, and the asphalt pavement is subjected to the coupling action of heat, light, oxygen and other environmental factors during the service process, thereby causing the aging phenomenon of physical and chemical properties and mechanical properties, which seriously affects the service life of the pavement.

[0004] In the prior art, the recycling of epoxy asphalt is mainly realized through the following two ways: one is the physical recycling method, that is, the old asphalt mixture is crushed and mixed with new asphalt mixture, but this method cannot effectively restore the mechanical properties of epoxy asphalt; the other is the chemical recycling method, that is, by adding a recycling agent or a reactive component, the performance of the old asphalt is restored by reacting with the aging components in the old asphalt.

[0005] The high toughness of epoxy asphalt is mainly realized by adding a toughening agent to form an elastic dispersed phase in the epoxy asphalt matrix, absorbing impact energy and improving the toughness of the material.

[0006] The existing anti-aging technology of asphalt mainly adds an anti-aging agent to inhibit the free radical oxidation reaction of asphalt. The anti-aging means of asphalt material mainly includes: adding an antioxidant, microwave radiation treatment and oxidative distillation, etc., and adding an antioxidant is the most commonly used method to improve the anti-aging performance of asphalt. Studies have shown that the antioxidant can slow down the aging of polymer modified asphalt by removing free radicals, peroxides or inhibiting the absorption of ultraviolet light of asphalt, and has a significant effect on improving the anti-aging performance of modified asphalt and its mixture. SUMMARY

[0007] In order to improve the anti-aging performance of epoxy asphalt and based on the judgment principle of the compatibility between asphalt and epoxy resin, the present invention prepares a compatibilized organic-inorganic composite anti-aging component through molecular structure design. The component structure contains highly active double bonds, which can be effectively compatible with asphalt, and the active carboxyl groups contained in the structure can participate in the curing and cross-linking reaction. At the same time, the synergistic effect between the hindered phenol groups in the structure and nano-titanium dioxide is utilized to finally prepare a high-toughness hot-mix regenerated epoxy asphalt with excellent compatibility and anti-aging performance.

[0008] To achieve the above-mentioned purpose, the present invention adopts the following technical solution: a high-toughness hot-mix recycled epoxy asphalt, the raw material formula of the high-toughness hot-mix recycled epoxy asphalt is: Old asphalt mixture, 80-120 parts by weight; Bisphenol A epoxy resin, 45-70 parts by weight; Curing agent 4,4-diaminodiphenylmethane, 30-50 parts by weight; Regeneration agent maleic anhydride grafted polypropylene, 2-4 parts by weight; Toughening agent: acrylic core-shell elastomer particles, 5-15 parts by weight; Compatibilized organic-inorganic composite anti-aging component, 1-10 parts by weight.

[0009] Furthermore, the method for preparing the high-toughness hot-mix recycled epoxy asphalt comprises the following steps: Step 1: crushing the old asphalt mixture to obtain crushed old asphalt mixture; Step 2: The crushed old asphalt mixture, bisphenol A epoxy resin, curing agent 4,4-diaminodiphenylmethane, regeneration agent maleic anhydride grafted polypropylene, toughening agent acrylate core-shell elastomer particles and volume-enhancing organic-inorganic composite anti-aging components are stirred and mixed evenly, and then hot-mixed to prepare high-toughness hot-mix recycled epoxy asphalt.

[0010] Furthermore, the particle size of the crushed old asphalt mixture is 1-15 mm.

[0011] Furthermore, the preparation method of the compatibilized organic-inorganic composite anti-aging component is: Based on the epoxy-hydroxyl ring-opening mechanism, trimethyl citrate and glycidyl methacrylate were used as raw materials to prepare an olefinic trimethyl citrate functional monomer. Based on the epoxy-hydroxyl ring-opening mechanism, an alkenylated trimethyl citrate silane coupling agent was prepared using alkenylated trimethyl citrate functional monomer and 3-(2,3-epoxypropoxy)propyltrimethoxysilane as raw materials. Based on the esterification reaction mechanism, under the catalysis of a protonic acid, the hydroxyl group in the alkenyl citrate trimethyl silane coupling agent reacts with the carboxyl group in the 3,5-di-tert-butyl-4-hydroxybenzoic acid to prepare the alkenyl citrate trimethyl silane coupling agent with a hindered phenol group; The surface of the nano titanium dioxide is modified by the alkenyl citrate trimethyl silane coupling agent with a hindered phenol group, and finally a hydrolysis reaction is performed to prepare the compatibilized organic-inorganic composite anti-aging component. The compatibilized organic-inorganic composite anti-aging component is prepared by first performing a hydrolysis reaction and then performing acidification.

[0012] Further, the protonic acid is one of p-toluenesulfonic acid or triflic acid.

[0013] Further, the particle size of the nano titanium dioxide is 20-50 nm.

[0014] Further, the high-toughness hot-mix recycled epoxy asphalt can be used for pavement paving.

[0015] The present application has the following advantages: Based on the epoxy ring-opening mechanism, the alkenyl citrate trimethyl functional monomer is prepared by taking citrate trimethyl and glycidyl methacrylate as raw materials. Based on the epoxy ring-opening mechanism, the alkenyl citrate trimethyl silane coupling agent is prepared by taking the alkenyl citrate trimethyl functional monomer and 3-(2,3-epoxypropoxy) propyl trimethoxysilane as raw materials. Based on the esterification reaction mechanism, the alkenyl citrate trimethyl silane coupling agent with a hindered phenol group is prepared by taking the alkenyl citrate trimethyl silane coupling agent and 3,5-di-tert-butyl-4-hydroxybenzoic acid as raw materials. The surface of the nano titanium dioxide is modified by the alkenyl citrate trimethyl silane coupling agent with a hindered phenol group, and finally a hydrolysis reaction is performed to prepare the compatibilized organic-inorganic composite anti-aging component. The high-toughness hot-mix recycled epoxy asphalt is prepared by taking old asphalt mixture, bisphenol A type epoxy resin, curing agent, regenerant, toughening agent and compatibilized organic-inorganic composite anti-aging component as raw materials, and through mixing and hot-mixing treatment. The experimental results prove that the high-toughness hot-mix recycled epoxy asphalt prepared by the present application has excellent properties of high toughness, recyclability, compatibility and anti-aging. Specific embodiments Example one:

[0016] The compatibilized organic-inorganic composite anti-aging component is prepared, including the following steps: (1) Preparation of the alkenyl citrate trimethyl ester group functional monomer, the preparation mechanism is that: under the action of catalyst boron trifluoride ether complex, the ring opening reaction occurs between the hydroxyl group in the citrate trimethyl ester and the epoxy group in the glycidyl methacrylate, the alkenyl citrate trimethyl ester group functional monomer is prepared, and the specific experimental steps are as follows: 2.4g of citrate trimethyl ester, 0.01g of boron trifluoride ether and 50mL of N,N-dimethylformamide are added into a 250mL three-necked flask equipped with a magnetic stirrer, a dropping funnel, a reflux condenser and a thermometer, the system is stirred uniformly, the temperature is raised to 75℃, then 1.5g of glycidyl methacrylate is added, constant temperature stirring is carried out for 5h, then ammonia is used to adjust the pH value of the system to 7, the solvent is removed by rotary evaporation, filtration is carried out, the product is placed in a vacuum drying oven at 60℃ for drying for 4h, and the alkenyl citrate trimethyl ester group functional monomer is prepared; (2) Preparation of the alkenyl citrate trimethyl ester group silane coupling agent, the preparation mechanism is that: under the action of catalyst boron trifluoride ether complex, the ring opening reaction occurs between the hydroxyl group in the alkenyl citrate trimethyl ester group functional monomer and the epoxy group in the 3-(2,3-epoxypropoxy) propyl trimethoxysilane, the alkenyl citrate trimethyl ester group silane coupling agent is prepared, and the specific experimental steps are as follows: 3.8g of the alkenyl citrate trimethyl ester group functional monomer, 0.02g of boron trifluoride ether and 100mL of N,N-dimethylformamide are added into a 250mL three-necked flask, heating and stirring are carried out, when the temperature rises to 80℃, 2.4g of 3-(2,3-epoxypropoxy) propyl trimethoxysilane is added, reaction is carried out for 4h, filtration is carried out, washing is carried out, and vacuum drying is carried out at 50℃ for 5h, and the alkenyl citrate trimethyl ester group silane coupling agent is prepared; (3) Preparation of the alkenyl citrate trimethyl ester group silane coupling agent with a hindered phenol group, the preparation mechanism is that: under the action of catalyst p-toluenesulfonic acid, the esterification reaction occurs between the hydroxyl group in the alkenyl citrate trimethyl ester group silane coupling agent and the carboxyl group in the 3,5-di-tert-butyl-4-hydroxybenzoic acid, the alkenyl citrate trimethyl ester group silane coupling agent with a hindered phenol group is prepared, and the specific experimental steps are as follows: 2.5g of 3,5-di-tert-butyl-4-hydroxybenzoic acid, 6.2g of the alkenyl citrate trimethyl ester group silane coupling agent and 0.15g of catalyst p-toluenesulfonic acid are added into a 250mL three-necked flask, 150mL of solvent cyclohexane is further added, the temperature is raised to 80℃ for reaction, the reaction is stopped after 8h, the solvent is removed by distillation under reduced pressure, then the product is washed with saturated sodium carbonate solution and distilled water for three times in sequence, and the product is recrystallized in 75% ethanol solution, and the alkenyl citrate trimethyl ester group silane coupling agent with a hindered phenol group is prepared; (4) Preparation of the alkenyl citrate trimethyl ester-based organic-inorganic composite anti-aging component, the preparation mechanism is: using the alkenyl citrate trimethyl ester-based silane coupling agent with hindered phenol group to modify the surface of nano titanium dioxide, and the alkenyl citrate trimethyl ester-based organic-inorganic composite anti-aging component is prepared, and the specific experimental steps are as follows: 2.5 g of the alkenyl citrate trimethyl ester-based silane coupling agent with hindered phenol group and 100 mL of ethanol are added into a three-necked flask, stirred at room temperature for 1 h, 4 g of nano titanium dioxide (particle size of 30 nm) is added, stirred under the conditions of ultrasonic and condensation reflux at 45℃ for 5 h, filtered, washed with ethanol, and dried at 80℃ for 12 h to prepare the alkenyl citrate trimethyl ester-based organic-inorganic composite anti-aging component.

[0017] (5) Preparation of the compatibilized organic-inorganic composite anti-aging component, the preparation mechanism is: the alkenyl citrate trimethyl ester-based organic-inorganic composite anti-aging component is first subjected to hydrolysis reaction in the presence of sodium hydroxide, and then acidified by hydrochloric acid to prepare the compatibilized organic-inorganic composite anti-aging component, and the specific experimental steps are as follows: 3 g of the alkenyl citrate trimethyl ester-based organic-inorganic composite anti-aging component is added into 50 mL of acetone, after stirring and dissolving, 1% NaOH is used to adjust the pH value of the system to 10, and the system is stirred at room temperature for 6 h, the acetone is removed by reduced pressure evaporation, the product is placed in a cold water bath, and 1% HCl is used to adjust the pH value of the system to 3.5 under stirring, and the solid is precipitated, filtered, and the filter cake is vacuum dried at 60℃ for 4 h to prepare the compatibilized organic-inorganic composite anti-aging component. Example Two:

[0018] Preparation of high-toughness hot-mix recycled epoxy asphalt I, including the following steps: Step one: 100 parts by weight of old asphalt mixture is crushed to prepare crushed old asphalt mixture with a particle size of 4 mm; Step two: 100 parts by weight of the crushed old asphalt mixture, 58 parts by weight of bisphenol A type epoxy resin (model E-44), 42 parts by weight of curing agent 4,4-diaminodiphenyl methane, 3 parts by weight of regenerant maleic anhydride grafted polypropylene (model QⅡ510), 10 parts by weight of toughening agent acrylate core-shell elastomer particles (model FM-40), and 5 parts by weight of compatibilized organic-inorganic composite anti-aging component are added into a mixer, stirred and mixed, and then hot-mixed at 170℃ for 8 min to prepare high-toughness hot-mix recycled epoxy asphalt I. Example Three:

[0019] Preparation of high-toughness hot-mix recycled epoxy asphalt II, including the following steps: Step one: 100 parts by weight of old asphalt mixture is crushed to prepare crushed old asphalt mixture with a particle size of 4 mm; Step two: 100 parts by weight of the crushed old asphalt mixture, 58 parts by weight of bisphenol A type epoxy resin (trade name E-44), 42 parts by weight of curing agent 4,4-diamino diphenyl methane, 3 parts by weight of regenerant maleic anhydride grafted polypropylene (model QII 510), 10 parts by weight of toughening agent acrylate core-shell elastomer particles (model FM-40), and 1 part by weight of compatibilized organic-inorganic composite anti-aging component are added to a mixer, and after stirring and mixing, high-toughness hot-mixing regenerated epoxy asphalt II is prepared by hot mixing at 170°C for 8 min. Example four:

[0020] High-toughness hot-mixing regenerated epoxy asphalt III is prepared by the following steps: Step one: 100 parts by weight of old asphalt mixture is crushed to obtain crushed old asphalt mixture with a particle size of 4 mm; Step two: 100 parts by weight of the crushed old asphalt mixture, 58 parts by weight of bisphenol A type epoxy resin (trade name E-44), 42 parts by weight of curing agent 4,4-diamino diphenyl methane, 3 parts by weight of regenerant maleic anhydride grafted polypropylene (model QII 510), 10 parts by weight of toughening agent acrylate core-shell elastomer particles (model FM-40), and 10 parts by weight of compatibilized organic-inorganic composite anti-aging component are added to a mixer, and after stirring and mixing, high-toughness hot-mixing regenerated epoxy asphalt III is prepared by hot mixing at 170°C for 8 min. Comparative example:

[0021] High-toughness hot-mixing regenerated epoxy asphalt IV is prepared by the following steps: Step one: 100 parts by weight of old asphalt mixture is crushed to obtain crushed old asphalt mixture with a particle size of 4 mm; Step two: 100 parts by weight of the crushed old asphalt mixture, 58 parts by weight of bisphenol A type epoxy resin (trade name E-44), 42 parts by weight of curing agent 4,4-diamino diphenyl methane, 3 parts by weight of regenerant maleic anhydride grafted polypropylene (model QII 510), 10 parts by weight of toughening agent acrylate core-shell elastomer particles (model FM-40), and 10 parts by weight of compatibilized organic-inorganic composite anti-aging component are added to a mixer, and after stirring and mixing, high-toughness hot-mixing regenerated epoxy asphalt IV is prepared by hot mixing at 170°C for 8 min. Performance test:

[0022] I. Compatibility test: The compatibility test of the epoxy asphalt was carried out according to the test method of segregation in JTG E20-2011 "Test code for asphalt and asphalt mixture of highway engineering", the high-toughness hot-mix recycled epoxy asphalt samples prepared by examples two to four and the comparative example were put into test tubes, stored at a temperature of (135±5) °C for 48 h, then placed in a refrigerator to stand for 4 h in a vertical state, so that the high-toughness hot-mix recycled epoxy asphalt sample was condensed into a solid, the test tube was taken out, and samples were taken at 1 / 3 of the upper end and the lower end, the difference value of the softening point was determined, and the compatibility of the epoxy asphalt was evaluated from the segregation degree; II. The mechanical properties, high-temperature stability, low-temperature performance and water stability of the high-toughness hot-mix recycled epoxy asphalt sample were tested according to JTG E20-2011; III. According to the requirements of the petrochemical industry standard "Epoxy asphalt for roads and bridges", the tensile test of the high-toughness hot-mix recycled epoxy asphalt sample was carried out according to the provisions in GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized or thermoplastic rubber", and the test piece was a dumbbell-shaped sample; The above test results are shown in Table 1 below; Table 1 Performance test results of high-toughness hot-mix recycled epoxy asphalt

[0023] IV. Anti-aging performance test: The penetration, softening point and ductility of the high-toughness hot-mix recycled epoxy asphalt sample were tested according to the national standards GB / T 4509-2010 "Determination of penetration of asphalt", GB / T 4507-2014 "Determination of softening point of asphalt - ring and ball method", and GB / T 4508-2010 "Determination of ductility of asphalt"; 50g±0.5g of the high-toughness hot-mix recycled epoxy asphalt sample was weighed and placed in a stainless steel dish with a diameter of 140 mm at room temperature, and then the sample dish was quickly placed in the oven turntable when the oven reached the set temperature of 163°C, the rotation speed of the turntable was 5.5 r / min, and the temperature was controlled at 163°C, the timing started when the temperature recovered to 162°C, and the duration was 5 h, to obtain the heat-oxidized asphalt sample, then the penetration, softening point and ductility of the heat-oxidized asphalt sample were tested again; Turn on the light control, temperature control and air switch of the ultraviolet aging box, the power of the ultraviolet aging lamp is 300W, the main wavelength is 375nm, the rotating speed of the sample tray is 5r / min, the height of the sample is 21cm, the distance from the center is 5cm, and the temperature is set to 60℃. 50g±0.5g of the high-toughness hot-mixed recycled epoxy asphalt sample is placed on the rotating disc of the ultraviolet aging box, and the temperature is kept constant during the test. The ultraviolet aging time is 6d, and the ultraviolet aged asphalt sample is obtained. Then, the penetration, softening point and ductility of the ultraviolet aged asphalt sample are tested again. The residual penetration ratio, softening point increment and residual ductility ratio of the high-toughness hot-mixed recycled epoxy asphalt after thermal oxidation and ultraviolet aging are calculated, the residual penetration ratio PPR=P2 / P1*100%, the softening point increment SPI=SP2-SP1, and the residual ductility ratio DRR=D2 / D1*100%, wherein P is the penetration of the asphalt, 0.1mm; SP is the softening point of the asphalt, ℃; D is the ductility of the asphalt, cm; 1 is before aging, and 2 is after aging. The test results are shown in Table 2 below. Table 2 Anti-aging performance test results of high-toughness hot-mixed recycled epoxy asphalt

[0024] From the experimental data in Table 1 and Table 2, the following conclusions can be drawn: With the increase of the amount of the compatibilized organic-inorganic composite anti-aging component, the compatibility of the epoxy resin and the asphalt is obviously improved, and a uniform system is formed. The Marshall stability of the high-toughness hot-mixed recycled epoxy asphalt I prepared by the application is greater than 40kN, the dynamic stability at 70℃ is greater than 30000 times / mm, the low-temperature bending strain at-10℃ is greater than 5000με, the residual stability and the freeze-thaw splitting strength ratio are both greater than 90%, the toughness is greater than 180N*mm, the recyclability is strong, the toughness is high, and the road performance is very excellent. Under different aging conditions, with the increase of the amount of the compatibilized organic-inorganic composite anti-aging component, the residual penetration ratio and the residual ductility ratio of the high-toughness hot-mixed recycled epoxy asphalt are obviously increased, and the softening point increment is gradually reduced, which indicates that the high-toughness hot-mixed recycled epoxy asphalt I prepared by the application has good anti-aging effect.

Claims

1. A high-toughness hot-mix recycled epoxy asphalt, characterized in that: The raw material formula of high toughness hot mix recycled epoxy asphalt is: Old asphalt mixture, 80-120 parts by weight; Bisphenol A epoxy resin, 45-70 parts by weight; Curing agent 4,4-diaminodiphenylmethane, 30-50 parts by weight; Regeneration agent maleic anhydride grafted polypropylene, 2-4 parts by weight; Toughening agent: acrylic core-shell elastomer particles, 5-15 parts by weight; Compatibilized organic-inorganic composite anti-aging component, 1-10 parts by weight.

2. The high-toughness hot-mix recycled epoxy asphalt according to claim 1, characterized in that: The method for preparing the high-toughness hot-mix regenerated epoxy asphalt comprises the following steps: Step 1: crushing the old asphalt mixture to obtain crushed old asphalt mixture; Step 2: The crushed old asphalt mixture, bisphenol A epoxy resin, curing agent 4,4-diaminodiphenylmethane, regeneration agent maleic anhydride grafted polypropylene, toughening agent acrylate core-shell elastomer particles and volume-enhancing organic-inorganic composite anti-aging components are stirred and mixed evenly, and then hot-mixed to prepare high-toughness hot-mix recycled epoxy asphalt.

3. The high-toughness hot-mix recycled epoxy asphalt according to claim 2, characterized in that: The particle size of the crushed old asphalt mixture is 1-15 mm.

4. A high-toughness hot-mix recycled epoxy asphalt according to claim 1 or 2, characterized in that: The preparation method of the compatibilized organic-inorganic composite anti-aging component is as follows: Based on the epoxy-hydroxyl ring-opening mechanism, trimethyl citrate and glycidyl methacrylate were used as raw materials to prepare an olefinic trimethyl citrate functional monomer. Based on the epoxy-hydroxyl ring-opening mechanism, an alkenylated trimethyl citrate silane coupling agent was prepared using alkenylated trimethyl citrate functional monomer and 3-(2,3-epoxypropoxy)propyltrimethoxysilane as raw materials. Based on the esterification reaction mechanism, under the catalysis of protonic acid, the hydroxyl group in the alkenylated trimethyl citrate silane coupling agent reacts with the carboxyl group in 3,5-di-tert-butyl-4-hydroxybenzoic acid to prepare an alkenylated trimethyl citrate silane coupling agent with a hindered phenol group. Nano-titanium dioxide is modified by an olefinic trimethyl citrate-based silane coupling agent having a hindered phenol group to prepare an olefinic trimethyl citrate-based organic-inorganic composite anti-aging component; The alkenylated trimethyl citrate-based organic-inorganic composite anti-aging component is first subjected to a hydrolysis reaction and then acidified to prepare a compatibilized organic-inorganic composite anti-aging component.

5. The high-toughness hot-mix recycled epoxy asphalt according to claim 4, characterized in that: The protonic acid is one of p-toluenesulfonic acid and trifluoromethanesulfonic acid.

6. The high-toughness hot-mix recycled epoxy asphalt according to claim 4, characterized in that: The particle size of the nano titanium dioxide is 20-50 nm.

7. The high-toughness hot-mix recycled epoxy asphalt according to claim 1, characterized in that: The high-toughness hot-mix recycled epoxy asphalt can be used for road paving.

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