Bio-oil-based composite regenerant for regenerated asphalt and preparation method of bio-oil-based composite regenerant

Abstract

The invention discloses a bio-oil-based composite regenerant for regenerated asphalt and a preparation method of the bio-oil-based composite regenerant, and relates to the technical field of road engineering. The preparation method comprises the following steps: step 1, reacting acrylic acid with epoxidized soybean oil to obtain acrylic acid grafted epoxidized soybean oil; (2) modifying silicon dioxide by adopting an amino silane coupling agent to obtain modified silicon dioxide; (3) activating lignin, and then modifying the lignin by using an unsaturated silane coupling agent to obtain modified lignin; (4) sequentially reacting acrylic acid grafted epoxidized soybean oil with the modified silicon dioxide and the modified lignin to obtain modified epoxidized soybean oil; step 2, (1) reacting maleic anhydride with castor oil to obtain maleic anhydride grafted castor oil; (2) reacting maleic anhydride grafted castor oil with the modified lignin to obtain modified castor oil; and step 3, uniformly mixing the biological asphalt, the modified epoxidized soybean oil, the modified castor oil and the like to obtain the biological oil-based composite regenerant.

Description

Technical Field

[0001] The present invention relates to the technical field of road engineering, and particularly to a bio-oil-based composite rejuvenator for recycled asphalt and a preparation method thereof. Background Art

[0002] During the long-term service process of asphalt pavement, under the action of ultraviolet rays, oxygen and loads, its light components gradually oxidize and are lost, resulting in the destruction of the asphalt colloid structure, manifested as hardening, embrittlement and decline in anti-fatigue performance, and then causing diseases such as cracking and rutting. To restore the flexibility and rheological properties of aged asphalt, the rejuvenator technology has become the core means for asphalt pavement repair. Traditional rejuvenators mostly rely on petroleum-based light oils to restore performance by supplementing the missing light components. However, such rejuvenators have obvious limitations: firstly, petroleum-based raw materials are non-renewable, and high carbon emissions are accompanied during the production process, which is contrary to the concept of green and sustainable development; secondly, the compatibility between the rejuvenator and aged asphalt is insufficient, and it is difficult to effectively penetrate into the deep layer of aged asphalt, resulting in a short-term repair effect; thirdly, most rejuvenators only focus on the restoration of flexibility, lack anti-aging functions, cannot delay the rate of secondary aging of asphalt, and have limited improvement in the adhesion to aggregates.

[0003] In recent years, bio-based rejuvenators have received attention due to advantages such as renewable raw materials and environmental friendliness. Vegetable oils such as epoxidized soybean oil and castor oil have been tried for the development of rejuvenators because of their molecular structures similar to asphalt. However, unmodified bio-oils have problems such as low viscosity, poor thermal stability, and insufficient polarity matching with asphalt, and direct use is likely to lead to deterioration of the high-temperature performance of recycled asphalt. In the prior art, although there are individual studies on grafting modification of epoxidized soybean oil with acrylic acid to introduce active groups, the functional group types of the modified products are single, the hydrogen bond interaction with asphalt is limited, and inorganic / organic reinforcing phases (such as silica, lignin) are not synergistically used, making it difficult to achieve a double improvement in antioxidant properties and structural repair. In addition, the modification of castor oil in traditional processes is mostly limited to transesterification reactions, and the characteristics of its high hydroxyl content cannot be effectively utilized, resulting in an insignificant enhancement effect on adhesion.

[0004] To address the above problems, there is an urgent need to develop a bio-based composite rejuvenator with high-efficiency regeneration, anti-aging and optimized construction performance. By molecular design, compounding bio-oil with functionalized nanomaterials and biomass-derived components to construct a multi-scale synergistic action system is expected to break through the performance bottleneck of existing rejuvenators and provide a new solution for the green maintenance of asphalt pavement. Summary of the Invention

[0005] The purpose of the present invention is to provide a bio-oil-based composite rejuvenator for recycled asphalt and a preparation method thereof to solve the problems raised in the prior art.

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

[0007] A preparation method of a bio - oil - based composite regenerant for recycled asphalt, comprising the following steps:

[0008] Step 1: Prepare modified epoxy soybean oil:

[0009] (1) React acrylic acid with epoxy soybean oil to obtain acrylic - acid - grafted epoxy soybean oil;

[0010] (2) Modify silica with an amino - silane coupling agent to obtain modified silica;

[0011] (3) Activate lignin, and then modify it with an unsaturated silane coupling agent to obtain modified lignin;

[0012] (4) React acrylic - acid - grafted epoxy soybean oil with modified silica and modified lignin in sequence to obtain modified epoxy soybean oil;

[0013] Step 2: Prepare modified castor oil:

[0014] (1) React maleic anhydride with castor oil to obtain maleic - anhydride - grafted castor oil;

[0015] (2) React maleic - anhydride - grafted castor oil with modified lignin to obtain modified castor oil;

[0016] Step 3: Mix bio - asphalt, modified epoxy soybean oil, modified castor oil, and surfactant evenly according to a proportional relationship to obtain a bio - oil - based composite regenerant.

[0017] Further, the preparation method of the modified epoxy soybean oil is as follows: (1) Add epoxy soybean oil and acrylic acid into a reaction vessel, stir and mix evenly, then add a catalyst and an inhibitor into the reaction vessel, and stir - react at 90 - 120 °C for 3 - 9 h, end the reaction, and obtain acrylic - acid - grafted epoxy soybean oil; (2) Add silica and an amino - silane coupling agent into an ethanol aqueous solution with a concentration of 60 - 80 wt%, stir - react at 40 - 70 °C for 1 - 6 h, discharge and dry to obtain modified silica; (3) Add lignin into a sodium hydroxide aqueous solution with a concentration of 0.8 - 1 mol / L, stir - react at 150 - 160 °C for 20 - 60 min, discharge and cool, wash and dry to obtain activated lignin; then add the activated lignin and an unsaturated silane coupling agent into an ethanol aqueous solution with a concentration of 60 - 80 wt%, stir - react at 40 - 70 °C for 1 - 6 h, discharge and dry to obtain modified lignin; (4) Add acrylic - acid - grafted epoxy soybean oil and modified silica into a blender, stir - mix at 80 - 120 °C for 1 - 3 h, then add the modified lignin into the blender, and continue to keep warm and stir - mix for 1 - 3 h to obtain modified epoxy soybean oil.

[0018] Further, the mass ratio of the epoxy soybean oil to acrylic acid is 4:(1 to 1.5).

[0019] Further, the addition amount of the catalyst is 1 to 2% of the total mass of the reactants.

[0020] Further, the addition amount of the inhibitor is 0.05 to 0.1% of the addition amount of acrylic acid.

[0021] Further, the proportional relationship among the silica, amino silane coupling agent, and aqueous ethanol solution is 1 g:(0.05 to 0.1) mL:10 mL; wherein, the amino silane coupling agent includes, but is not limited to, one or a combination of more than one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, and γ-aminopropylmethyldiethoxysilane.

[0022] Further, the proportional relationship between the lignin and the aqueous sodium hydroxide solution is (1 to 3) g:5 mL.

[0023] Further, the proportional relationship among the activated lignin, unsaturated silane coupling agent, and aqueous ethanol solution is 1 g:(0.05 to 0.1) mL:10 mL; wherein, the unsaturated silane coupling agent includes, but is not limited to, one or a combination of more than one of vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris(2-methoxyethoxy)silane, and γ-methacryloxypropyltrimethoxysilane.

[0024] Further, the mass ratio of the acrylic acid-grafted epoxy soybean oil, modified silica, and modified lignin is 1:(0.01 to 0.03):(0.1 to 0.3).

[0025] The light components of asphalt will gradually decrease due to long-term oxidation, which will cause the asphalt to gradually become hard and brittle, resulting in the easy damage of asphalt pavement. Therefore, in order to restore the flexibility of asphalt, a light oil compatible with asphalt needs to be added to penetrate into the oxidized and aged asphalt, thereby repairing and improving the aged asphalt. Based on this, in the present invention, the carboxyl group of acrylic acid first reacts with the epoxy group on epoxy soybean oil. By controlling the amount of polyacrylic acid, acrylic acid-modified epoxy soybean oil with double bonds, hydroxyl groups and residual epoxy groups can be prepared. Then, an amino silane coupling agent and an unsaturated silane coupling agent are used to modify silica and lignin respectively, so that amino groups are grafted onto silica and double bonds are grafted onto lignin. The amino groups on the modified silica can react with the residual epoxy groups on the acrylic acid-modified epoxy soybean oil, and the double bonds on the modified lignin can bond with the double bonds on the acrylic acid-modified epoxy soybean oil, and finally modified epoxy soybean oil is prepared. The modified epoxy soybean oil contains rich double bond structures, benzene rings and other structures, which are similar to the asphalt structure, so the two have good compatibility. At the same time, the modified epoxy soybean oil is also grafted with silica and lignin. On the one hand, both of them can endow asphalt with certain antioxidant properties, thereby delaying the aging rate of subsequent asphalt. On the other hand, both of them contain rich hydroxyl groups, which can form hydrogen bonds with polar groups in the aged asphalt, play a role in repairing the colloidal structure broken by oxidation, and enhance the connection between the modified epoxy soybean oil and asphalt. That is, the modified epoxy soybean oil has excellent compatibility with the aged asphalt, can actively repair the aged asphalt, restore the flexibility of the aged asphalt to a certain extent, and can endow the aged asphalt with excellent antioxidant properties.

[0026] Further, the preparation method of the modified castor oil is as follows: (1) Add castor oil and maleic anhydride into a reaction vessel, stir and react at 75-85°C for 3-9 hours, and end the reaction to obtain maleic anhydride-grafted castor oil; (2) Add the maleic anhydride-grafted castor oil and the modified lignin into a blender, stir and mix at 80-120°C for 1-3 hours to obtain the modified castor oil.

[0027] Further, the mass ratio of the castor oil to the maleic anhydride is 10:(0.8-1).

[0028] Further, the mass ratio of the maleic anhydride-grafted castor oil to the modified lignin is 1:(0.1-0.3).

[0029] Considering that the viscosity of epoxidized soybean oil is not good, in order to better improve the workability of asphalt during construction and the adhesion with mineral materials in the follow-up, in the present invention, castor oil with better viscosity is further modified. After modification with maleic anhydride, it undergoes double bond bonding with modified lignin to prepare modified castor oil. The modified castor oil has good compatibility with both modified epoxidized soybean oil and asphalt, and can greatly synergistically repair and improve aged asphalt with modified epoxidized soybean oil.

[0030] Further, the bio-oil-based composite rejuvenator for recycled asphalt comprises the following components: by mass, 50 parts of bio-asphalt, 30 - 40 parts of modified epoxidized soybean oil, 10 - 20 parts of modified castor oil, and 2 - 5 parts of surfactant.

[0031] Further, the surfactant is a non-ionic surfactant.

[0032] Further, the incorporation amount of the bio-oil-based composite rejuvenator is 2 - 8% of the mass of the aged asphalt.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] 1. The present invention prepares modified epoxidized soybean oil, which realizes the double improvement of antioxidant property and structure repair by synergistically combining inorganic / organic reinforcing phases; the modified epoxidized soybean oil has excellent compatibility with aged asphalt, and can greatly restore the flexibility of aged asphalt; in addition, it can endow aged asphalt with certain antioxidant properties and delay its subsequent aging rate;

[0035] 2. The present invention prepares modified castor oil, which also has excellent compatibility with aged asphalt, and plays a role in synergistically restoring the flexibility of aged asphalt with modified epoxidized soybean oil;

[0036] 3. Modified castor oil has better viscosity compared with modified epoxidized soybean oil. By appropriately adjusting its addition amount, a rejuvenator with more excellent performance can be obtained, that is, it can improve the workability of aged asphalt during construction and enhance the adhesion with mineral materials in the follow-up.

[0037] In summary, the present invention finally prepares a bio-based oil composite rejuvenator that can improve the flexibility of aged asphalt, restore its rheological properties, make it have excellent workability during construction, and at the same time endow it with certain anti-aging properties and enhance adhesion. Specific Embodiments

[0038] Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] It should be noted that the following parts are by weight, and there are no special restrictions on the purchasing manufacturers of the raw materials involved in the present invention. Exemplarily, they include:

[0040] Acrylic acid with a purity of 99% was purchased from Hunan Maigao New Materials Technology Co., Ltd.;

[0041] Epoxidized soybean oil with a purity of 99%, product number: 8013-07-8, castor oil with a purity of 99%, product number: 8001-79-4, lignin with a purity of 99%, product number: 9005-53-2, silica with a purity of 99% and a particle size of 10 - 30 nm, γ-aminopropyltrimethoxysilane with a purity of 99%, vinyltriethoxysilane with a purity of 99%, maleic anhydride with a purity of 99%, and lauryl alcohol polyoxyethylene ether with a purity of 99% were all purchased from Hubei Yongkuo Technology Co., Ltd.;

[0042] Bio-asphalt was purchased from Beijing Jiage Weiye Building Technology Co., Ltd.;

[0043] The said parts are 10 g per part.

[0044] Example 1: A preparation method of a bio-oil-based composite regenerant for recycled asphalt:

[0045] Step 1: Prepare modified epoxidized soybean oil:

[0046] (1) Add 40 parts of epoxidized soybean oil and 13 parts of acrylic acid into a reaction vessel, stir and mix evenly, then add 0.8 part of potassium carbonate and 0.01 part of hydroquinone into the reaction vessel, and stir and react at 110°C for 6 h. After the reaction ends, acrylic acid-grafted epoxidized soybean oil is obtained; (2) Add 1.5 parts of silica and 1.2 mL of γ-aminopropyltrimethoxysilane into 150 mL of 70 wt% ethanol aqueous solution, stir and react at 50°C for 3 h, discharge and dry to obtain modified silica; (3) Add 10 parts of lignin into 0.9 mol / L sodium hydroxide aqueous solution, stir and react at 155°C for 40 min, discharge and cool, wash and dry to obtain activated lignin; then add 10 parts of activated lignin and 8 mL of vinyltriethoxysilane into 1 L of 70 wt% ethanol aqueous solution, stir and react at 50°C for 3 h, discharge and dry to obtain modified lignin; (4) Add 40 parts of acrylic acid-grafted epoxidized soybean oil and 0.8 part of modified silica into a blender, stir and mix at 100°C for 2 h, then add 8 parts of modified lignin into the blender, and continue to stir and mix at the same temperature for 2 h to obtain modified epoxidized soybean oil;

[0047] Step 2: Prepare modified castor oil: (1) Add 20 parts of castor oil and 1.8 parts of maleic anhydride into a reaction vessel, stir and react at 80 °C for 6 h, end the reaction, and obtain maleic anhydride grafted castor oil; (2) Add 20 parts of maleic anhydride grafted castor oil and 4 parts of modified lignin into a blender, stir and mix at 100 °C for 2 h to obtain modified castor oil;

[0048] Step 3: Mix 50 parts of bio-asphalt, 35 parts of modified epoxy soybean oil, 15 parts of modified castor oil, and 4 parts of lauryl alcohol polyoxyethylene ether evenly to obtain a bio-oil-based composite regenerant.

[0049] Example 2: A preparation method of a bio-oil-based composite regenerant for recycled asphalt:

[0050] Step 1: Prepare modified epoxy soybean oil:

[0051] (1) Add 40 parts of epoxy soybean oil and 10 parts of acrylic acid into a reaction vessel, stir and mix evenly, then add 0.5 part of potassium carbonate and 0.005 part of hydroquinone into the reaction vessel, stir and react at 90 °C for 3 h, end the reaction, and obtain acrylic acid grafted epoxy soybean oil; (2) Add 1.5 parts of silicon dioxide and 0.75 mL of γ-aminopropyltrimethoxysilane into 150 mL of 70 wt% ethanol aqueous solution, stir and react at 40 °C for 1 h, discharge and dry to obtain modified silicon dioxide; (3) Add 10 parts of lignin into 0.8 mol / L sodium hydroxide aqueous solution, stir and react at 150 °C for 20 min, discharge and cool, wash and dry to obtain activated lignin; then add 10 parts of activated lignin and 5 mL of vinyltriethoxysilane into 1 L of 70 wt% ethanol aqueous solution, stir and react at 40 °C for 1 h, discharge and dry to obtain modified lignin; (4) Add 40 parts of acrylic acid grafted epoxy soybean oil and 0.4 part of modified silicon dioxide into a blender, stir and mix at 80 °C for 1 h, then add 4 parts of modified lignin into the blender, and continue to stir and mix at the same temperature for 1 h to obtain modified epoxy soybean oil;

[0052] Step 2: Prepare modified castor oil: (1) Add 20 parts of castor oil and 1.6 parts of maleic anhydride into a reaction vessel, stir and react at 75 °C for 3 h, end the reaction, and obtain maleic anhydride grafted castor oil; (2) Add 20 parts of maleic anhydride grafted castor oil and 2 parts of modified lignin into a blender, stir and mix at 80 °C for 1 h to obtain modified castor oil;

[0053] Step 3: Mix 50 parts of bio-asphalt, 35 parts of modified epoxy soybean oil, 15 parts of modified castor oil, and 4 parts of lauryl alcohol polyoxyethylene ether evenly to obtain a bio-oil-based composite regenerant.

[0054] Example 3: A preparation method of a bio - oil - based composite rejuvenator for recycled asphalt:

[0055] Step 1: Prepare modified epoxy soybean oil:

[0056] (1) Add 40 parts of epoxy soybean oil and 15 parts of acrylic acid into a reaction vessel, stir and mix evenly, then add 1.1 parts of potassium carbonate and 0.015 parts of hydroquinone into the reaction vessel, stir and react at 120 °C for 6 h, end the reaction, and obtain acrylic acid - grafted epoxy soybean oil; (2) Add 1.5 parts of silica and 1.5 mL of γ - aminopropyltrimethoxysilane into 150 mL of 70 wt% ethanol aqueous solution, stir and react at 70 °C for 6 h, discharge and dry to obtain modified silica; (3) Add 10 parts of lignin into 1 mol / L sodium hydroxide aqueous solution, stir and react at 160 °C for 60 min, discharge and cool, wash and dry to obtain activated lignin; then add 10 parts of activated lignin and 10 mL of vinyltriethoxysilane into 1 L of 70 wt% ethanol aqueous solution, stir and react at 70 °C for 6 h, discharge and dry to obtain modified lignin; (4) Add 40 parts of acrylic acid - grafted epoxy soybean oil and 1.2 parts of modified silica into a blender, stir and mix at 120 °C for 3 h, then add 12 parts of modified lignin into the blender, continue to keep warm and stir and mix for 3 h to obtain modified epoxy soybean oil;

[0057] Step 2: Prepare modified castor oil: (1) Add 20 parts of castor oil and 2 parts of maleic anhydride into a reaction vessel, stir and react at 85 °C for 9 h, end the reaction, and obtain maleic anhydride - grafted castor oil; (2) Add 20 parts of maleic anhydride - grafted castor oil and 6 parts of modified lignin into a blender, stir and mix at 120 °C for 3 h to obtain modified castor oil;

[0058] Step 3: Mix 50 parts of bio - asphalt, 35 parts of modified epoxy soybean oil, 15 parts of modified castor oil, and 4 parts of lauryl alcohol polyoxyethylene ether evenly to obtain a bio - oil - based composite rejuvenator.

[0059] The following is based on Example 1, and Comparative Examples 1 - 4 are set as follows:

[0060] Comparative Example 1: Comparative Example 1 is based on Example 1 and is adjusted as follows: Do not introduce castor oil, and keep other processes unchanged. The specific details are as follows:

[0061] A preparation method of a bio - oil - based composite rejuvenator for recycled asphalt:

[0062] Step 1: Prepare modified epoxy soybean oil:

[0063] (1) Add 40 parts of epoxidized soybean oil and 13 parts of acrylic acid into a reaction vessel, stir and mix evenly. Then add 0.8 part of potassium carbonate and 0.01 part of hydroquinone into the reaction vessel, and stir and react at 110 °C for 6 h. End the reaction to obtain acrylic acid grafted epoxidized soybean oil; (2) Add 1.5 parts of silica and 1.2 mL of γ-aminopropyltrimethoxysilane into 150 mL of 70 wt% ethanol aqueous solution, stir and react at 50 °C for 3 h, discharge and dry to obtain modified silica; (3) Add 10 parts of lignin into 0.9 mol / L sodium hydroxide aqueous solution, stir and react at 155 °C for 40 min, discharge and cool, wash and dry to obtain activated lignin; Then add 10 parts of activated lignin and 8 mL of vinyltriethoxysilane into 1 L of 70 wt% ethanol aqueous solution, stir and react at 50 °C for 3 h, discharge and dry to obtain modified lignin; (4) Add 40 parts of acrylic acid grafted epoxidized soybean oil and 0.8 part of modified silica into a blender, stir and mix at 100 °C for 2 h, then add 8 parts of modified lignin into the blender, continue to keep warm and stir and mix for 2 h to obtain modified epoxidized soybean oil;

[0064] Step 2: Mix 50 parts of bio-asphalt, 35 parts of modified epoxidized soybean oil and 4 parts of lauryl alcohol polyoxyethylene ether evenly to obtain a bio-oil-based composite regenerant.

[0065] Comparative Example 2: Comparative Example 2 is based on Example 1, with the following adjustments: no silica is introduced, and other processes remain unchanged, specifically as follows:

[0066] A preparation method of a bio-oil-based composite regenerant for recycled asphalt:

[0067] Step 1: Prepare modified epoxidized soybean oil:

[0068] (1) Add 40 parts of epoxidized soybean oil and 13 parts of acrylic acid into a reaction vessel, stir and mix evenly. Then add 0.8 part of potassium carbonate and 0.01 part of hydroquinone into the reaction vessel, and stir and react at 110 °C for 6 h. End the reaction to obtain acrylic acid grafted epoxidized soybean oil; (2) Add 10 parts of lignin into 0.9 mol / L sodium hydroxide aqueous solution, stir and react at 155 °C for 40 min, discharge and cool, wash and dry to obtain activated lignin; Then add 10 parts of activated lignin and 8 mL of vinyltriethoxysilane into 1 L of 70 wt% ethanol aqueous solution, stir and react at 50 °C for 3 h, discharge and dry to obtain modified lignin; (3) Add 40 parts of acrylic acid grafted epoxidized soybean oil and 8 parts of modified lignin into a blender, stir and mix at 100 °C for 2 h to obtain modified epoxidized soybean oil;

[0069] Step 2: Preparation of modified castor oil: (1) Add 20 parts of castor oil and 1.8 parts of maleic anhydride into a reaction vessel, stir and react at 80 °C for 6 h, end the reaction, and obtain maleic anhydride grafted castor oil; (2) Add 20 parts of maleic anhydride grafted castor oil and 4 parts of modified lignin into a blender, stir and mix at 100 °C for 2 h to obtain modified castor oil;

[0070] Step 3: Mix 50 parts of bio-asphalt, 35 parts of modified epoxy soybean oil, 15 parts of modified castor oil, and 4 parts of lauryl alcohol polyoxyethylene ether evenly to obtain a bio-oil-based composite regenerant.

[0071] Comparative Example 3: Comparative Example 3 is based on Example 1, with the following adjustments: lignin is not introduced, and other processes remain unchanged, specifically as follows:

[0072] A preparation method of a bio-oil-based composite regenerant for recycled asphalt:

[0073] Step 1: Preparation of modified epoxy soybean oil:

[0074] (1) Add 40 parts of epoxy soybean oil and 13 parts of acrylic acid into a reaction vessel, stir and mix evenly, then add 0.8 part of potassium carbonate and 0.01 part of hydroquinone into the reaction vessel, stir and react at 110 °C for 6 h, end the reaction, and obtain acrylic acid grafted epoxy soybean oil; (2) Add 1.5 parts of silica and 1.2 mL of γ-aminopropyltrimethoxysilane into 150 mL of 70 wt% ethanol aqueous solution, stir and react at 50 °C for 3 h, discharge and dry to obtain modified silica; (3) Add 40 parts of acrylic acid grafted epoxy soybean oil and 0.8 part of modified silica into a blender, stir and mix at 100 °C for 2 h to obtain modified epoxy soybean oil;

[0075] Step 2: Preparation of modified castor oil: (1) Add 20 parts of castor oil and 1.8 parts of maleic anhydride into a reaction vessel, stir and react at 80 °C for 6 h, end the reaction, and obtain modified castor oil;

[0076] Step 3: Mix 50 parts of bio-asphalt, 35 parts of modified epoxy soybean oil, 15 parts of modified castor oil, and 4 parts of lauryl alcohol polyoxyethylene ether evenly to obtain a bio-oil-based composite regenerant.

[0077] Comparative Example 4: Comparative Example 4 is based on Example 1, with the following adjustments: epoxy soybean oil and castor oil are not modified, and other processes remain unchanged, specifically as follows:

[0078] A preparation method of a bio-oil-based composite regenerant for recycled asphalt:

[0079] Step 1: Mix 50 parts of bio-asphalt, 35 parts of epoxidized soybean oil, 15 parts of castor oil, and 4 parts of lauryl alcohol polyoxyethylene ether evenly to obtain a bio-oil-based composite regenerant.

[0080] Performance test: The following is to conduct relevant performance tests on the bio-oil-based composite regenerants prepared in Examples 1-3 and Comparative Examples 1-4 according to the technical standards of JTGF41-2008;

[0081] The specific test results are shown in Table 1 below:

[0082] Table 1

[0083]

[0084] Result analysis: It can be seen from the data in Table 1 above that the bio-oil-based composite regenerant prepared in the examples of the present invention meets the technical specification standards specified in JTGF41-2008.

[0085] Further, the prepared bio-oil-based composite regenerant is incorporated into the aged asphalt, and the incorporation amount is 5% of the mass of the aged asphalt. After stirring and mixing at 130 °C for 30 min, the regenerated asphalt is obtained; then, another part of the regenerated asphalt is placed in an air environment at 160 °C and baked for 48 h to obtain the aged regenerated asphalt; the performances of the regenerated asphalt and the aged regenerated asphalt are tested respectively, and the specific results are shown in Table 2 below:

[0086] Table 2

[0087]

[0088]

[0089] Result analysis: It can be seen from the data in Table 2 above that for the aged asphalt improved by the bio-oil-based composite regenerant prepared by the present invention, its penetration, softening point, and ductility have been significantly improved compared with the aged asphalt, indicating that through the modification treatment of epoxidized soybean oil and castor oil, the two work together synergistically to promote the repair of aged asphalt and improve its flexibility; in addition, the regenerated asphalt treated with the bio-oil-based composite regenerant prepared by the present invention still has good performance after being baked at 160 °C for 48 h, indicating that the bio-oil-based composite regenerant prepared by the present invention has the effect of improving the anti-aging performance of aged asphalt.

[0090] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A bio-oil-based composite regenerant for recycled asphalt, characterized in that: It comprises the following components: by mass parts, 50 parts of bio-asphalt, 30 - 40 parts of modified epoxy soybean oil, 10 - 20 parts of modified castor oil, and 2 - 5 parts of surfactant.

2. The preparation method of a bio-oil-based composite regenerant for recycled asphalt according to claim 1, characterized in that: It comprises the following steps: Step 1: Prepare modified epoxy soybean oil: (1) React acrylic acid with epoxy soybean oil to obtain acrylic acid-grafted epoxy soybean oil; (2) Modify silica with an amino-silane coupling agent to obtain modified silica; (3) Activate lignin, and then modify it with an unsaturated silane coupling agent to obtain modified lignin; (4) React acrylic acid-grafted epoxy soybean oil with modified silica and modified lignin in sequence to obtain modified epoxy soybean oil; Step 2: Prepare modified castor oil: (1) React maleic anhydride with castor oil to obtain maleic anhydride-grafted castor oil; (2) React maleic anhydride-grafted castor oil with modified lignin to obtain modified castor oil; Step 3: Mix bio-asphalt, modified epoxy soybean oil, modified castor oil, and surfactant evenly to obtain a bio-oil-based composite regenerant.

3. The preparation method of a bio-oil-based composite regenerant for recycled asphalt according to claim 2, wherein: The preparation method of the modified epoxy soybean oil is as follows: (1) Add epoxy soybean oil and acrylic acid into a reaction vessel, stir and mix evenly, then add a catalyst and an inhibitor into the reaction vessel, and stir and react at 90 - 120 °C for 3 - 9 h, end the reaction, and obtain acrylic acid-grafted epoxy soybean oil; (2) Add silica and an amino-silane coupling agent into an ethanol aqueous solution with a concentration of 60 - 80 wt%, stir and react at 40 - 70 °C for 1 - 6 h, discharge and dry to obtain modified silica; (3) Add lignin into a sodium hydroxide aqueous solution with a concentration of 0.8 - 1 mol / L, stir and react at 150 - 160 °C for 20 - 60 min, discharge and cool, wash and dry to obtain activated lignin; then add the activated lignin and an unsaturated silane coupling agent into an ethanol aqueous solution with a concentration of 60 - 80 wt%, stir and react at 40 - 70 °C for 1 - 6 h, discharge and dry to obtain modified lignin; (4) Add acrylic acid-grafted epoxy soybean oil and modified silica into a blender, stir and mix at 80 - 120 °C for 1 - 3 h, then add the modified lignin into the blender, and continue to keep warm and stir and mix for 1 - 3 h to obtain modified epoxy soybean oil.

4. The preparation method of a bio-oil-based composite regenerant for recycled asphalt according to claim 3, characterized in that: The mass ratio of the epoxy soybean oil to acrylic acid is 4:(1 - 1.5); the addition amount of the catalyst is 1 - 2% of the total mass of the reactants; the addition amount of the inhibitor is 0.05 - 0.1% of the addition amount of acrylic acid; the proportional relationship among the silica, amino-silane coupling agent, and ethanol aqueous solution is 1 g:(0.05 - 0.1) mL:10 mL; the proportional relationship between the lignin and sodium hydroxide aqueous solution is (1 - 3) g:5 mL; the proportional relationship among the activated lignin, unsaturated silane coupling agent, and ethanol aqueous solution is 1 g:(0.05 - 0.1) mL:10 mL; the mass ratio of the acrylic acid-grafted epoxy soybean oil, modified silica, and modified lignin is 1:(0.01 - 0.03):(0.1 - 0.3).

5. The preparation method of a bio-oil-based composite regenerant for recycled asphalt according to claim 4, characterized in that: The amino silane coupling agent includes one or a combination of more than one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, and γ-aminopropylmethyldiethoxysilane; the unsaturated silane coupling agent includes one or a combination of more than one of vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris(2-methoxyethoxy)silane, and γ-methacryloxypropyltrimethoxysilane.

6. The preparation method of a bio-oil-based composite regenerant for recycled asphalt according to claim 2, characterized in that: The preparation method of the modified castor oil is as follows: (1) Add castor oil and maleic anhydride into a reaction vessel, stir and react at 75-85 °C for 3-9 h, end the reaction, and obtain maleic anhydride-grafted castor oil; (2) Add maleic anhydride-grafted castor oil and modified lignin into a blender, stir and mix at 80-120 °C for 1-3 h to obtain modified castor oil.

7. The preparation method of a bio-oil-based composite regenerant for recycled asphalt according to claim 6, characterized in that: The mass ratio of the castor oil to the maleic anhydride is 10:(0.8-1); the mass ratio of the maleic anhydride-grafted castor oil to the modified lignin is 1:(0.1-0.3).

8. The preparation method of a bio-oil-based composite regenerant for recycled asphalt according to claim 2, characterized in that: The surfactant is a non-ionic surfactant.

9. The preparation method of a bio-oil-based composite regenerant for recycled asphalt according to claim 2, characterized in that: The incorporation amount of the bio-oil-based composite regenerant is 2-8% of the mass of the aged asphalt.

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