A bio-oil-based warm-mixing agent, a preparation method thereof, a warm-mixing type dry-process SBS asphalt modifier and a preparation method thereof

Abstract

The application relates to the field of road engineering materials, and particularly discloses a bio-oil-based warm-mixing agent, a preparation method of the bio-oil-based warm-mixing agent, a warm-mixing dry-process SBS asphalt modifier and a preparation method of the warm-mixing dry-process SBS asphalt modifier. The warm-mixing agent is prepared through amidation reaction of raw materials including bio-oil and triethylenetetramine under the action of a catalyst, and the structural formula of the bio-oil is shown in formula (1): wherein R1, R2 and R3 are all C12-C18 saturated linear alkanes. The warm-mixing dry-process SBS asphalt modifier is prepared from the following components: butadiene-styrene-butadiene copolymer, polyolefin elastomer, bio-oil-based warm-mixing agent, SBS filling oil and sulfur stabilizer. After the warm-mixing agent is used in the asphalt modifier, the shortcomings of a traditional SBS modifier, such as high melting point, high viscosity and difficulty in quick melting and dispersion in asphalt, can be overcome, and the problem that the SBS modifier cannot be directly used as a dry-process modifier is solved.

Description

Technical Field

[0001] This application relates to the field of road engineering materials, and more specifically, it relates to a bio-oil-based warm mix agent and its preparation method, and a warm mix dry SBS asphalt modifier and its preparation method. Background Technology

[0002] With increasing demands for highway construction quality, SBS modified asphalt, due to its excellent high and low temperature performance, has become an essential building material for high-grade highway construction. Traditional wet-process modified asphalt is produced in modified asphalt plants by grinding base asphalt and SBS modifiers, and then transported to mixing plants to be mixed with aggregates. This method suffers from long production cycles, high equipment requirements, large investments, and frequent performance degradation during storage. Dry-process SBS modified asphalt, compared to the traditional wet-process, eliminates the factory processing step, significantly reducing energy consumption during production. It also avoids molecular cracking and segregation of SBS modifiers during high-temperature storage, resulting in significant low-carbon and environmentally friendly characteristics. However, traditional SBS modifiers have drawbacks such as high melting point, high viscosity, and difficulty in rapid dissolution and dispersion in asphalt, making them unsuitable for direct use as dry-process modifiers. On the other hand, in wet-process or dry-process SBS modified asphalt, the modified asphalt mixture generally requires a mixing temperature of 175-185℃ to achieve a good modification effect. This high-temperature mixing significantly increases the aging of the asphalt and leads to high energy consumption. Harmful fumes such as nitrogen oxides and sulfides, when mixed with gases like methane and hydrogen sulfide in the tunnel, pose a potential explosion risk under high temperatures or sparks. The large amount of carcinogens in asphalt fumes severely interferes with vision, causing eye discomfort, skin allergies, and respiratory problems, directly endangering the physical and mental health of construction workers. Warm-mix technology can effectively alleviate these problems.

[0003] In view of the above-mentioned problems, such as the long production cycle, high equipment requirements, and performance degradation during storage of traditional wet-process modified asphalt, and the disadvantages of traditional SBS modifiers such as high melting point, high viscosity, and difficulty in rapid dissolution and dispersion in asphalt, which prevent them from being used directly as dry-process modifiers, as well as the high production and construction temperatures and large emissions of harmful gases in traditional hot-mix asphalt mixtures, it is essential to innovatively combine dry-process SBS with warm-mix technology to provide a warm-mix dry-process SBS asphalt modifier and its preparation method. Summary of the Invention

[0004] This application provides a bio-oil-based warm mix additive and its preparation method, as well as a warm mix dry SBS asphalt modifier and its preparation method. These solutions address the problems of long production cycles, high equipment requirements, and performance degradation during storage associated with traditional wet-process modified asphalt. Furthermore, they overcome the drawbacks of traditional SBS modifiers, such as high melting point, high viscosity, and difficulty in rapid dissolution and dispersion in asphalt. This also addresses the issues of their inability to be directly used as dry-process modifiers, and the high temperatures and harmful gas emissions associated with traditional hot-mix asphalt mixtures during production and construction.

[0005] In a first aspect, this application provides a bio-oil-based warm mixing agent, which adopts the following technical solution: A bio-oil-based warm mix agent, wherein the warm mix agent is prepared by an amidation reaction of raw materials including bio-oil and triethylenetetramine under the action of a catalyst, and the structural formula of the bio-oil is shown in formula (1): (1) Among them, R1, R2 and R3 are all saturated straight-chain alkanes of C12 to C18.

[0006] By adopting the above technical solution and preparing the warm mix agent through the above reaction, the molecular chain has a lipophilic long-chain saturated hydrocarbon at one end and a hydrophilic amine group at the other end, exhibiting surface activity. It is a highly efficient asphalt warm mix agent that can reduce the temperature of asphalt mixtures during mixing, paving, and compaction by more than 30°C at a low dosage, achieving the effect of warm mixing. It also allows for the dry application of SBS modifiers, and the preparation process of SBS modifiers is very convenient. It can effectively reduce the oxidation degree of asphalt binder, reduce the probability of shortened asphalt service life due to asphalt aging, and reduce energy consumption and asphalt fume generation during the mixing process, resulting in significant low-carbon benefits and environmental protection effects. Furthermore, R1, R2, and R3 in bio-oils are C12-C18 saturated straight-chain alkanes. Saturated straight-chain alkanes with excessively high C content cannot plasticize or modify SBS in the resulting warm mix agent, thus having a limited effect on increasing the melting rate of SBS. Moreover, their high melting point and long melting time make it difficult to quickly melt and disperse in asphalt, thus failing to exert a proper warm mix effect. The warm mix agent prepared from the aforementioned bio-oils can melt and disperse more effectively.

[0007] Furthermore, the bio-oil is obtained by dehydrating and purifying waste cooking oil to a water content of less than 1%, resulting in a separated and purified bio-oil. The mass ratio of triethylenetetramine to bio-oil is 1:4-6. The amount of catalyst used is 1%-2% of the total mass of triethylenetetramine and bio-oil.

[0008] Secondly, this application provides a method for preparing a bio-oil-based warm mixing agent, which adopts the following technical solution: A method for preparing a bio-oil-based warm mixing agent includes the following steps: heating bio-oil to 40-60℃ for preheating, adding triethylenetetramine to a reaction vessel and starting stirring, then adding the preheated bio-oil and raising the temperature to 60-80℃, adding a catalyst, and maintaining the temperature for 2-4 hours to obtain the bio-oil warm mixing agent.

[0009] By adopting the above technical solutions, the preparation process of the warm mixing agent of this application is very simple and does not require high reaction conditions. It can use biological oils separated and purified from waste cooking oil, which makes use of waste, lowers costs, and is more low-carbon and environmentally friendly.

[0010] Thirdly, this application provides a warm-mix dry SBS asphalt modifier using the above-mentioned bio-oil-based warm-mix agent, employing the following technical solution: A warm-mix dry-process SBS asphalt modifier using the above-mentioned bio-oil-based warm-mix agent. The raw materials, by weight, include the following components: butadiene-styrene-butadiene copolymer: 40-60 parts; polyolefin elastomer: 20-40 parts; bio-oil-based warm-mix agent: 5-10 parts; SBS filler oil: 5-10 parts; sulfur stabilizer: 1-3 parts.

[0011] Furthermore, the butadiene-styrene-butadiene copolymer is linear SBS with a molecular weight of approximately 70,000 to 100,000. If the molecular weight of SBS is too small, it is difficult to form a network structure in asphalt, resulting in poor modification effect. If the molecular weight of SBS is too large, the melting speed is slow, the fluidity is poor, and it is difficult to achieve rapid melting and dispersion, which is not conducive to dry application.

[0012] Furthermore, the polyolefin elastomer is a POE elastomer with a melting temperature of not less than 80℃ and a melt index greater than 20g / 10min. If the melting temperature is too low, the high-temperature performance is poor, which is not conducive to improving the modification effect of the modified asphalt. If the melt index is low, the viscosity is high during use, making it difficult to disperse quickly and uniformly in the asphalt to achieve the modification effect.

[0013] Furthermore, the SBS filler oil is any one of naphthenic oil or paraffinic oil. The SBS filler oil can enter the SBS molecular chain, swell the SBS, increase the melting rate of SBS, and improve the compatibility of SBS with asphalt.

[0014] Fourthly, this application provides a method for preparing a warm-mix dry SBS asphalt modifier using the above-mentioned bio-oil-based warm-mix agent, employing the following technical solution: A method for preparing a warm-mix dry SBS asphalt modifier, characterized by comprising the following steps: (1) Linear SBS, POE elastomer, bio-oil-based warm mix agent, and SBS filler oil are mixed to obtain the first product A.

[0015] (2) The first product A prepared in step (1) is mixed with sulfur stabilizer, and after being mixed evenly, it is crushed to obtain warm-mix dry SBS asphalt modifier.

[0016] Furthermore, the mixing temperature is 70-120℃, and the mixing time is 3-5 minutes. If the mixing temperature is too low or the mixing time is too short, the mixing effect of each component is poor, and the torque of the mixer is too high, which will cause great damage to the equipment and make it difficult to stabilize production. If the mixing temperature is too high or the mixing time is too long, it will easily cause SBS molecules to age and break down, affecting the later use effect.

[0017] In summary, this application has the following beneficial effects: 1. The bio-oil-based warm mix agent prepared by this application using bio-oil purified from waste cooking oil as raw material is a low molecular weight liquid. On the one hand, at the mixing temperature of the warm mix agent and SBS filler oil, it can be mixed into the SBS molecular chain, increasing the distance between SBS molecular chains, reducing the intermolecular forces of SBS, increasing the mobility of SBS at high temperatures, and reducing the melting point and melt viscosity of SBS. This allows SBS to be rapidly melted and dispersed in asphalt within tens of seconds of mixing in the asphalt production process, achieving dry modification of asphalt. On the other hand, using waste cooking oil as raw material is a waste utilization method, resulting in lower costs and greater low-carbon environmental protection.

[0018] 2. The warm mixing agent in this application not only has readily available raw materials and lower cost, but also has a simple preparation process with low requirements, making it suitable for widespread application.

[0019] 3. The warm-mix dry-process SBS asphalt modifier of this application can be used in a dry process, modifying the asphalt during the mixing and production of asphalt mixtures. This greatly reduces energy consumption in the production process of wet-process modified asphalt, and has significant environmental protection characteristics. At the same time, it avoids the SBS molecular chain cracking and segregation that occur during the high-temperature storage of wet-process modified asphalt, which helps to improve the technical performance and durability of modified asphalt. Detailed Implementation

[0020] The present application will be further described in detail below with reference to the embodiments.

[0021] This embodiment provides a bio-oil-based warm mixing agent, which is prepared by an amidation reaction of raw materials including bio-oil and triethylenetetramine under the action of a catalyst.

[0022] The bio-oil is obtained by dehydrating and purifying waste cooking oil to a water content of less than 1%, and was purchased from Xuzhou Hengyuan Bio-oil Technology Co., Ltd. The structural formula of the bio-oil in this embodiment is shown in formula (1): (1) Among them, R1, R2 and R3 are all saturated straight-chain alkanes of C12 to C18.

[0023] The mass ratio of triethylenetetramine to bio-oil is 1:4-6. The amount of catalyst used is 1%-2% of the total mass of triethylenetetramine and bio-oil; in this example, the catalyst is specifically 4-dimethylaminopyridine (DMAP).

[0024] This embodiment also provides a method for preparing a bio-oil-based warm mixing agent, including the following steps: heating the bio-oil to 40-60℃ for preheating, adding triethylenetetramine to the reaction vessel and starting stirring, then adding the preheated bio-oil, raising the temperature to 60-80℃, adding a catalyst, and keeping the reaction at this temperature for 2-4 hours to obtain the bio-oil warm mixing agent.

[0025] The reaction pathway described above is as follows:

[0026] This embodiment provides a warm-mix dry SBS asphalt modifier using the above-mentioned bio-oil-based warm-mix agent. The raw materials include the following components by weight: butadiene-styrene-butadiene copolymer: 40-60 parts; polyolefin elastomer: 20-40 parts; bio-oil-based warm-mix agent: 5-10 parts; SBS filler oil: 5-10 parts; sulfur stabilizer: 1-3 parts.

[0027] The butadiene-styrene-butadiene copolymer is a linear SBS with a molecular weight of approximately 70,000-100,000. The polyolefin elastomer is a POE elastomer with a melting temperature of not less than 80°C and a melt index greater than 20 g / 10 min. It can be either Dow POE8401 or POE8402. Specifically, Dow POE8402 is used in the embodiments of this application.

[0028] SBS filler oil can be either naphthenic oil or paraffin oil.

[0029] Fourthly, this application provides a method for preparing a warm-mix dry SBS asphalt modifier using the above-mentioned bio-oil-based warm-mix agent, employing the following technical solution: A method for preparing a warm-mix dry-process SBS asphalt modifier includes the following steps: (1) Linear SBS, POE elastomer, bio-oil-based warm mix agent, and SBS filler oil are mixed to obtain the first product A.

[0030] (2) The first product A prepared in step (1) is mixed with sulfur stabilizer, and after being mixed evenly, it is crushed to obtain warm-mix dry SBS asphalt modifier.

[0031] The following is an illustration through specific examples.

[0032] Example 1 Example 1 provides a bio-oil-based warm mix agent, which is prepared by an amidation reaction of raw materials including bio-oil and triethylenetetramine under the action of a catalyst.

[0033] A method for preparing a bio-oil-based warm mixing agent includes the following steps: Bio-oil refined from waste cooking oil is preheated to 40°C. Triethylenetetramine is added to the reactor and stirred. Then, the preheated bio-oil is added, and the temperature is raised to 60°C. 4-Dimethylaminopyridine (DMAP) catalyst is added, and the reaction is maintained at this temperature for 3 hours to obtain a bio-oil warming agent. The mass ratio of triethylenetetramine to bio-oil is 1:4.0, and the amount of catalyst used is 1% of the total mass of triethylenetetramine and bio-oil.

[0034] This embodiment also provides a method for preparing a warm-mix dry-process SBS asphalt modifier, including the following steps: (1) Weigh 4000g of linear SBS, 200g of polyolefin elastomer (POE), 50g of bio-oil-based warm mix agent, and 50g of naphthenic oil and add them to a rotor mixer for mixing. The mixing temperature is 70℃ and the mixing time is 5min. After the mixing is completed, discharge the material and cool it to room temperature. Then add it to a pulverizer to pulverize the mixed material into 1~2cm large particles to obtain the first product A.

[0035] (2) Add the first product A prepared in step (1) and 10g of sulfur stabilizer to a low-speed mixer for mixing. After mixing evenly, it is sent to a liquid nitrogen cryogenic pulverizer for cryogenic pulverization and pulverized into 20-40 mesh powder particles to obtain warm-mix dry SBS asphalt modifier 1.

[0036] Example 2

[0037] The difference between Example 2 and Example 1 is that: A method for preparing a warm-mix dry-process SBS asphalt modifier includes the following steps: (1) First, weigh 6000g of linear SBS, 400g of polyolefin elastomer (POE), 100g of bio-oil-based warm mix agent, and 100g of naphthenic oil and add them to a rotor mixer for mixing. The mixing temperature is 120℃ and the mixing time is 5min. After the mixing is completed, discharge and cool to room temperature. Then add the mixture to a pulverizer to crush the mixed material into 1~2cm large particles to obtain the first product A.

[0038] (2) Add the first product A prepared in step (1) and 30g of sulfur stabilizer to a low-speed mixer for mixing. After mixing evenly, it is sent to a liquid nitrogen cryogenic pulverizer for cryogenic pulverization and pulverized into 20-40 mesh powder particles to obtain warm-mix dry SBS asphalt modifier 2.

[0039] Example 3

[0040] The difference between Example 3 and Example 1 is that: A method for preparing a warm-mix dry-process SBS asphalt modifier includes the following steps: (1) Weigh 5000g of linear SBS, 300g of polyolefin elastomer (POE), 80g of bio-oil-based warm mix agent, and 70g of paraffin oil respectively and add them to a rotor mixer for mixing. The mixing temperature is 100℃ and the mixing time is 4min. After the mixing is completed, discharge the material and cool it to room temperature. Then add it to a pulverizer to crush the mixed material into 1~2cm large particles to obtain the first product A.

[0041] (2) Add the first product A prepared in step (1) and 15g of sulfur stabilizer to a low-speed mixer for mixing. After mixing evenly, it is sent to a liquid nitrogen cryogenic pulverizer for cryogenic pulverization and pulverized into 20-40 mesh powder particles to obtain warm-mix dry SBS asphalt modifier 3.

[0042] Example 4

[0043] The difference between Example 4 and Example 1 is that: A method for preparing a warm-mix dry-process SBS asphalt modifier includes the following steps: (1) Weigh 4000g of linear SBS, 200g of polyolefin elastomer (POE), 75g of bio-oil-based warm mix agent, and 75g of paraffin oil respectively and add them to a rotor mixer for mixing. The mixing temperature is 120℃ and the mixing time is 3min. After the mixing is completed, discharge and cool to room temperature. Then add it to a pulverizer to crush the mixed material into 1~2cm large particles to obtain the first product A.

[0044] (2) Add the first product A prepared in step (1) and 20g of sulfur stabilizer to a low-speed mixer for mixing. After mixing evenly, it is sent to a liquid nitrogen cryogenic pulverizer for cryogenic pulverization and pulverized into 20-40 mesh powder particles to obtain warm-mix dry SBS asphalt modifier 4.

[0045] Example 5

[0046] The difference between Example 5 and Example 1 is that:

[0047] A method for preparing a bio-oil-based warm mixing agent is provided, comprising the following steps: Bio-oil refined from waste cooking oil is preheated to 50°C. Triethylenetetramine is added to the reactor and stirred. Then, the preheated bio-oil is added, and the temperature is raised to 70°C. 4-Dimethylaminopyridine (DMAP) catalyst is added, and the reaction is maintained at this temperature for 3 hours to obtain a bio-oil warming agent. The mass ratio of triethylenetetramine to bio-oil is 1:5.0, and the amount of catalyst used is 1.5% of the total mass of triethylenetetramine and bio-oil.

[0048] Example 6

[0049] The difference between Example 6 and Example 1 is that: A method for preparing a bio-oil-based warm mixing agent is provided, comprising the following steps: Bio-oil refined from waste cooking oil is preheated to 60°C. Triethylenetetramine is added to the reactor and stirring is started. Then, a certain amount of bio-oil is added, and the temperature is raised to 80°C. 4-Dimethylaminopyridine (DMAP) catalyst is added, and the reaction is kept at this temperature for 3 hours to obtain a bio-oil warming agent. The mass ratio of triethylenetetramine to bio-oil is 1:6, and the amount of catalyst used is 2% of the total mass of triethylenetetramine and bio-oil.

[0050] Comparative Example Comparative Example 1 A method for preparing a warm-mix dry-process SBS asphalt modifier includes the following steps: (1) Weigh 4000g of linear SBS, 200g of polyolefin elastomer (POE), 0g of bio-oil-based warm mix agent, and 75g of paraffin oil and add them to a rotor mixer for mixing. The mixing temperature is 120℃ and the mixing time is 3min. After the mixing is completed, discharge the material and cool it to room temperature. Then add it to a pulverizer to crush the mixed material into 1~2cm large particles to obtain the first product A.

[0051] (2) Add the first product A prepared in step (1) and 20g of sulfur stabilizer to a low-speed mixer for mixing. After mixing evenly, it is sent to a liquid nitrogen cryogenic pulverizer for cryogenic pulverization and pulverized into 20-40 mesh powder particles to obtain dry SBS asphalt modifier without warm mixing agent.

[0052] Comparative Example 2 A method for preparing a warm-mix dry-process SBS asphalt modifier includes the following steps: (1) Weigh out 4000g of linear SBS, 200g of polyolefin elastomer (POE), 75g of Defuron warm mix agent (Xi'an Bowang New Material Technology Co., Ltd.), and 75g of paraffin oil respectively, and add them to the rotor mixer in sequence. The mixture is subjected to intensive mixing at a temperature of 120℃ for 3 minutes. After intensive mixing, the mixture is discharged and cooled to room temperature. Then, it is added to a pulverizer to crush the intensively mixed material into 1-2 cm large particles to obtain the first product A.

[0053] (2) The first product A prepared in step (1) and 20g of sulfur stabilizer are added to a low-speed mixer for mixing. After mixing evenly, the mixture is sent to a liquid nitrogen cryogenic pulverizer for cryogenic pulverization and pulverized into 20-40 mesh powder particles to obtain dry SBS asphalt modifier containing commercially available warm mix agent.

[0054] Comparative Example 3 A method for preparing a warm-mix dry-process SBS asphalt modifier includes the following steps: (1) Weigh 4000g of linear SBS, 200g of polyolefin elastomer (POE), 75g of Sasobit warm mix agent (Xi'an Bowang New Material Technology Co., Ltd.), and 75g of paraffin oil respectively and add them to a rotor mixer for internal mixing. The mixing temperature is 120℃ and the mixing time is 3min. After the mixing is completed, discharge and cool to room temperature. Then add the mixture to a pulverizer to pulverize the mixed material into 1~2cm large particles to obtain the first product A.

[0055] (2) The first product A prepared in step (1) and 20g of sulfur stabilizer are added to a low-speed mixer for mixing. After mixing evenly, the mixture is sent to a liquid nitrogen cryogenic pulverizer for cryogenic pulverization and pulverized into 20-40 mesh powder particles to obtain dry SBS asphalt modifier containing commercially available warm mix agent.

[0056] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the mass ratio of triethylenetetramine to bio-oil is 1:7.

[0057] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the preparation method of a bio-oil-based warm mixing agent includes the following steps: the bio-oil refined from waste cooking oil is heated to 40°C for preheating, triethylenetetramine is added to the reaction vessel and stirring is started, then the preheated bio-oil is added, and the temperature is raised to 80°C. 4-Dimethylaminopyridine (DMAP) catalyst is added, and the reaction is kept at this temperature for 3 hours to obtain the bio-oil warm mixing agent, wherein the mass ratio of triethylenetetramine to bio-oil is 1:4, and the amount of catalyst used is 1% of the total mass of triethylenetetramine and bio-oil.

[0058] Performance testing (1) The melt index of the warm-mix dry SBS asphalt modifier prepared in the examples and comparative examples was tested using a melt index tester (test temperature: 190℃, weight of weight: 2.16kg) to evaluate the melting rate of the warm-mix dry SBS asphalt modifier.

[0059] (2) A dry mixing experiment was conducted in an indoor mixing pot (180℃, 5-10mm aggregate, mixing for 1 min) to observe the melt residue of the warm-mix dry SBS asphalt modifier and to qualitatively evaluate the melt dispersion performance of the warm-mix dry SBS asphalt modifier. The test results are shown in Table 1.

[0060] Table 1 Melt Index and Dry Dispersibility of SBS Asphalt Modifier

[0061] Table 1 shows that: pure linear SBS has a melt index of 0 g / 10 min, and after being mixed with stone in a 180℃ mixing pot for 1 min, it remains in the form of SBS modifier and is basically unmelted. Comparative Example 1, without the addition of bio-oil-based warm mix additive, has a melt index of 0.6 g / 10 min, with only partial modification and melting, leaving the majority as melted modifier. Comparative Example 3 uses Sasobit solid warm mix additive, which has no solubilizing effect on SBS and is similar to the effect of not adding warm mix additive. Comparative Example 2 uses an imported liquid warm mix additive, which has a certain compatibilizing effect on SBS, but the effect is limited, leaving a small amount of unmelted SBS particles after dry mixing. The six warm-mix dry-process SBS modifiers prepared using this application (Examples 1-6) all exhibited melt flow indices greater than 2.0 g / 10 min. Furthermore, in indoor dry-mix experiments, after 1 min of mixing, the modifier completely melted and adhered to the aggregate surface, with no unmelted modifier residue observed, meeting the technical requirements for dry-process SBS modifiers in T / CHTS 20003—2018 (Technical Guidelines for Dry-Process SBS Modified Asphalt Mixtures for Highway Pavements). This demonstrates that the warm-mix dry-process SBS asphalt modifier prepared in this application possesses excellent melting speed and dispersion performance. In terms of melt flow index, the order of melt flow indices for Examples 1-6 is: Example 2 > Example 4 > Example 3 > Example 1 ≈ Example 5 ≈ Example 6. The relatively lower melt flow indices of Examples 1, 5, and 6 are due to the lowest SBS filler oil and POE content in these three examples, which collectively affected the melting speed and dispersibility of the modifier. Furthermore, based on Comparative Examples 4 and 5, it can be seen that the parameters in the warm mix preparation process affect the performance of the final warm mix product, which in turn affects the melting rate and dispersion performance of the warm mix dry SBS asphalt modifier.

[0062] (3) The asphalt mixture road performance of the warm-mix dry SBS prepared in the examples and comparative examples was evaluated. The commonly used AC-13 asphalt mixture was used, the asphalt-aggregate ratio was 5.0%, and the dosage of warm-mix dry SBS asphalt modifier was 6% of the asphalt mass (internal admixture, the mass ratio of base asphalt to modifier was 94:6), that is, the base asphalt was 4.7% and the warm-mix dry SBS modifier was 0.3%. According to the requirements of the "Technical Specification for Construction of Highway Asphalt Pavement" (JTG F40—2004), the aggregate was first heated to 150-160℃, the No. 70 Class A road petroleum asphalt was heated to 130-140℃, and the mixing pot was heated to 160℃. The heated aggregate and warm-mix dry SBS asphalt modifier were put into the mixing pot. At the mixing temperature of 160℃, the aggregate and modifier were first dry-mixed for 30-40 seconds, then the base asphalt was added and mixed for 90 seconds, and finally the mineral powder was added and mixed for another 90 seconds. The modified asphalt mixture was then discharged and kept warm in an oven at 150℃ for 30 minutes. Finally, the specimens required for the experiment were formed at 140℃. Compared with the conventional SBS modified asphalt mixture, the forming temperature was reduced by 25℃. The test results are shown in Table 2.

[0063] The effects of conventional wet-process ID SBS modified asphalt were compared. The asphalt-aggregate ratio of the wet-process modified asphalt AC-13 was 5.0%. The aggregate heating temperature was 175-185℃, the SBS modified asphalt was heated to 155-160℃, and the mixing temperature was 175℃. The aggregate was first dry-mixed for 10 seconds, then the wet-process SBS modified asphalt was added and mixed for 90 seconds, and finally the mineral powder was added and mixed for another 90 seconds. The wet-process modified asphalt mixture was then discharged and kept in an oven at 175℃ for 30 minutes. Finally, the specimens required for the experiment were molded at 165℃. The test results are shown in Table 2.

[0064] Table 2 Performance test results of SMA-13 ​​asphalt mixture

[0065] Table 2 shows the road performance test results of AC-13 asphalt mixture. As can be seen from Table 2, the AC-13 asphalt mixtures prepared by the six warm-mix dry-process SBS asphalt modifiers prepared in Examples 1-6 of this application all meet the technical requirements after the molding temperature is reduced by 25℃. Comparing the road performance of AC-13 asphalt mixtures prepared with wet-process ID SBS modified asphalt, it can be seen that the asphalt mixtures of Examples 1-6 have slightly better performance than the wet-process ID modified asphalt mixtures. This indicates that the warm-mix dry-process SBS asphalt modifier prepared in this application has a significant warm-mix effect, and the molded asphalt mixture still has excellent road performance after the molding temperature is reduced. However, in Comparative Example 1, after the temperature is reduced (140℃), the asphalt mixture has a higher porosity, and its residual stability ratio, freeze-thaw splitting strength ratio, and low-temperature beam failure strain are poor, failing to meet the technical requirements. After the temperature was reduced (140℃), the porosity of the asphalt mixtures in Comparative Examples 2 and 3 met the requirements, indicating that the commercially available warm mix additives have a warm mix effect and can reduce the construction and molding temperature of the asphalt mixtures. However, the dynamic stability at 60℃ and the low-temperature beam failure strain at -10℃ of Comparative Examples 2 and 3 were lower than those of conventional modified asphalt. This is because the solubilization and modification effect of conventional warm mix additives on SBS is poor, and the SBS in the dry process modifier cannot be fully utilized. The performance of the asphalt mixture is lower than that of the traditional wet process ID modified asphalt mixture. Therefore, Comparative Examples 2 and 3 cannot be used as dry process SBS modifiers.

[0066] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A bio-oil-based warm mixing agent, characterized in that, The warm mixing agent is prepared by an amidation reaction of raw materials including bio-oil and triethylenetetramine under the action of a catalyst. The structural formula of the bio-oil is shown in formula (1): （1） Among them, R1, R2 and R3 are all saturated straight-chain alkanes of C12~C18; bio-oil is the bio-oil obtained by dehydrating and purifying waste cooking oil to a water content of less than 1%. The preparation method of the bio-oil-based warm mixing agent includes the following steps: heating the bio-oil to 40-60℃ for preheating, adding triethylenetetramine to the reaction vessel and starting stirring, then adding the preheated bio-oil, raising the temperature to 60-80℃, adding the catalyst, and keeping the reaction at this temperature for 2-4 hours to obtain the bio-oil warm mixing agent; the mass ratio of triethylenetetramine to bio-oil is 1:4-6.

2. The bio-oil-based warm mixing agent according to claim 1, characterized in that, The amount of catalyst used is 1%-2% of the total mass of triethylenetetramine and bio-oil.

3. A method for preparing a bio-oil-based warm mixing agent as described in any one of claims 1-2, characterized in that, Includes the following steps: The bio-oil is preheated to 40-60℃. Triethylenetetramine is added to the reaction vessel and stirred. Then the preheated bio-oil is added, and the temperature is raised to 60-80℃. A catalyst is added, and the reaction is maintained at this temperature for 2-4 hours to obtain the bio-oil temperature mixing agent.

4. A warm-mix dry-process SBS asphalt modifier using the bio-oil-based warm-mix agent as described in any one of claims 1-2, characterized in that, The raw materials include the following components by weight: butadiene-styrene-butadiene copolymer: 40-60 parts; polyolefin elastomer: 20-40 parts; bio-oil-based warm mix agent: 5-10 parts; SBS filler oil: 5-10 parts; sulfur stabilizer: 1-3 parts.

5. A warm-mix dry-process SBS asphalt modifier according to claim 4, characterized in that, The butadiene-styrene-butadiene copolymer is linear SBS with a molecular weight of 70,000-100,000.

6. A warm-mix dry-process SBS asphalt modifier according to claim 4, characterized in that, The polyolefin elastomer is a POE elastomer with a melting temperature of not less than 80°C and a melt index greater than 20 g / 10 min.

7. A method for preparing a warm-mix dry-process SBS asphalt modifier according to any one of claims 4-6, characterized in that, Includes the following steps: (1) Linear SBS, POE elastomer, bio-oil-based warm mix agent, and SBS filler oil are mixed in an intensive manner to obtain the first product A; (2) The first product A prepared in step (1) is mixed with sulfur stabilizer, and after being mixed evenly, it is crushed to obtain warm-mix dry SBS asphalt modifier.

8. The preparation method of a warm-mix dry-process SBS asphalt modifier according to claim 7, characterized in that, The mixing temperature is 70-120℃, and the mixing time is 3-5 minutes.

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