Warm mixing regenerant and preparation method thereof

Abstract

The invention relates to the technical field of road engineering materials, in particular to a warm mixing regenerant and a preparation method thereof.The warm mixing regenerant is prepared from, by mass, 70-85% of functional active components and 15-30% of solid carriers, and the functional active components are adsorbed to the solid carriers; the functional active components comprise the following components in percentage by mass: 60-80 wt% of a compound waste engine oil regenerant and 20-40 wt% of octadecanamide; the compound waste engine oil regenerant comprises the following components in parts by mass: 100 parts of waste engine oil, 30-50 parts of aromatic makeup oil, 2-5 parts of an antioxidant and 5-10 parts of a toughening agent, the solid carrier is modified diatomite with amino functional groups in gradient distribution on the surface and in pores; the diatomite carrier is modified through amino gradient, so that slow and continuous release in the later stage is realized, and a long-acting warm-mixing viscosity reduction effect is provided.

Description

Technical Field

[0001] This invention relates to the field of road engineering materials technology, and in particular to a warm-mix regenerator and its preparation method. Background Technology

[0002] With the arrival of the peak maintenance season for high-grade highways, the recycling of large quantities of reclaimed asphalt pavement (RAP) has become crucial for the industry's sustainable development. Hot recycling technology is the primary means of restoring the pavement performance of RAP. This process typically requires the addition of recycling agents to replenish the lightweight components lost by aging asphalt, restoring its colloidal structure and physical properties. Simultaneously, warm mix technology has been widely adopted to reduce mixing and compaction temperatures, thereby decreasing energy consumption and harmful gas emissions. Therefore, in the high-volume hot recycling process of RAP, it is often necessary to use both recycling agents and warm mix agents simultaneously.

[0003] Currently, recycling agents and warm mix additives are added separately, resulting in complex processes and high costs. To address this issue, existing technologies have proposed a functional compounding approach: one is a liquid compound product, which integrates functions but suffers from drawbacks such as inconvenient storage and transportation, difficulty in metering, and difficulty in mixing with cold RAP materials; the other is a solid product formed by adsorbing liquid components onto a porous carrier, which improves workability, but the active components in this product are mostly weakly adsorbed onto the carrier, leading to rapid release during mixing, making it difficult to achieve controllable effects, and contributing little to improving the long-term performance of asphalt.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the general background of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] This invention provides a warm-mix regenerator and its preparation method, which can effectively solve the problems in the background art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A warm-mix regenerator, by mass percentage, comprises 70-85 wt% of a functional active component and 15-30 wt% of a solid carrier, wherein the functional active component is adsorbed onto the solid carrier; By mass percentage, the functional active ingredients include: 60-80 wt% of compounded waste engine oil regenerator and 20-40 wt% of stearamide; By weight, the compound waste engine oil regeneration agent includes 100 parts waste engine oil, 30-50 parts aromatic supplement oil, 2-5 parts antioxidant and 5-10 parts toughening agent; The solid carrier is modified diatomaceous earth with a gradient distribution of amino functional groups on its surface and within its pores.

[0007] The warm-mix regenerator of the present invention modifies the surface of diatomaceous earth with an aminosilane coupling agent, thereby covalently bonding basic amino functional groups to its surface. When the basic amino functional groups are combined with functional active components, they can form secondary chemical forces such as hydrogen bonds with the amide groups of stearamide molecules. Based on this effect, the adsorption state of stearamide on the surface of the solid carrier changes from simple physical filling to a gradient distribution structure with partial chemical anchoring. This results in different functional active components having different release rates when heated, solving the problem of excessively rapid and uncontrollable release of active components in solid products in the prior art. When solid recycling agents and recycled asphalt pavement materials are dry-mixed and heated in a mixing pot, the release behavior of functional active components exhibits a temporal sequence due to differences in adsorption strength: the oil in the compounded waste engine oil recycling agent is preferentially released mainly through physical adsorption, quickly replenishing the light components and providing initial lubrication to the aged asphalt; subsequently, the amino-anchored stearamide is slowly desorbed and released under higher thermodynamic drive, thereby continuously providing warm-mix viscosity reduction function during the mixing and compaction stages of the mixture. This temporal release characteristic enables the recycled mixture to maintain a more stable working viscosity throughout the entire construction process; After the active components are released, some of the amino groups grafted onto the surface of the solid carrier can still be exposed in the asphalt mastic. The amino groups can interact with the acidic oxygen-containing groups generated by oxidation in the aged asphalt, which helps to improve the interfacial adhesion between recycled asphalt and aggregates and enhance the water damage resistance of recycled asphalt mixtures.

[0008] Furthermore, the aromatic supplement oil is G23 aromatic oil.

[0009] G23 aromatic oil has a high aromatic content and a suitable distillation range, which can directly replenish the aromatics lost by aged asphalt, effectively dissolve and disperse asphaltene agglomerates formed by oxidation, thereby restoring the stability of the asphalt colloidal structure. At the same time, its moderate viscosity can adjust the overall viscosity of the regenerator oil phase based on waste engine oil, so that the final functional active components maintain good wettability to the pores of the solid carrier, and also have suitable fluidity to facilitate diffusion during mixing. In addition, G23 aromatic oil has good compatibility with waste engine oil and stearamide, ensuring the homogeneity and storage stability of the functional active components in subsequent processes.

[0010] Furthermore, the antioxidant is 2,6-di-tert-butyl-p-cresol (BHT).

[0011] The hindered phenolic functional groups in BHT can specifically inhibit the oxidative aging chain reaction of recycled asphalt during service, and slow down its hardening and embrittlement trend caused by secondary aging.

[0012] Furthermore, the toughening agent is diisooctyl phthalate (DOP).

[0013] DOP enables recycled asphalt to maintain better flexibility and deformation capacity at low temperatures, thus directly addressing the problems of increased brittleness and decreased crack resistance that may occur in recycled asphalt due to aging.

[0014] Furthermore, the method for preparing the solid support includes: S1 involves crushing, sieving, and drying the diatomaceous earth raw material to obtain surface-activated diatomaceous earth. In this step, the particle size of the diatomaceous earth raw material is reduced by mechanical crushing, and the particle size distribution is controlled by sieving. Subsequently, the physically adsorbed water is removed by drying. During the drying process, the silanol groups on the surface of the diatomaceous earth are exposed and activated, providing reaction sites for subsequent chemical bonding with silane coupling agents.

[0015] In step S2, an aminosilane coupling agent is added to an alcohol solvent. Under ice-water bath cooling and inert gas protection, a catalytic amount of water is added, and the mixture is stirred and hydrolyzed at 0-10°C for 10-30 minutes to obtain a hydrolysate mainly composed of oligomeric siloxanes. The low temperature and inert protection in this step inhibit the self-condensation side reaction of silane molecules, allowing them to undergo controlled hydrolysis to form reactive silanol groups and partially condensed oligomeric siloxanes. The hydrolysate is mainly composed of linear or cyclic oligomers, rather than highly cross-linked polymers, which is beneficial for the subsequent formation of a uniform and highly grafted modified layer on the diatomaceous earth surface.

[0016] S3 involves mixing surface-activated diatomaceous earth with a hydrolysate in batches and conducting a multi-step reaction at different temperatures. This step achieves gradient grafting of silanes onto the diatomaceous earth surface through batch addition and multi-step reactions at different temperatures. The first batch of diatomaceous earth reacts with the hydrolysate at a lower temperature, preferentially anchoring oligomeric siloxanes to the outer surface and large pore entrances of the diatomaceous earth. Subsequently, the remaining diatomaceous earth is added and the temperature is increased, promoting further condensation and diffusion of the remaining oligomers into the deeper pores of the diatomaceous earth, thereby forming chemically bonded (Si-O-Si) ammonia on the surface and within the pores. The functionalized layer exhibits a gradient decrease in amino grafting density from high to low, extending from the outer surface of diatomaceous earth and macropore inlets to deep pores. A strong chemical reaction zone is formed on the diatomaceous earth surface and at the pore inlets, while a weak physical reaction zone is formed on the inner wall of the pores. The compounded waste oil regenerator in the weak physical reaction zone can be rapidly desorbed under relatively low heat, achieving early replenishment of light oils and rapid lubrication of aged asphalt. Stearamide in the strong reaction zone requires higher heat energy to desorb, thus achieving slow and continuous release in the later stages, providing a long-lasting warm-mix viscosity reduction effect.

[0017] After the S4 reaction, the solid product is separated, washed, and dried to obtain the solid support. This step obtains modified diatomaceous earth through solid-liquid separation, then washes to remove physically adsorbed unreacted silanes and byproducts, and finally dries to remove residual solvent and water. The resulting product is a diatomaceous earth support with amino functional groups covalently grafted onto its surface. Its surface chemical properties change from inert to basic and reactive, while maintaining a porous structure, making it suitable for loading subsequent functional active components.

[0018] Further, the specific method of S3 is as follows: the surface-activated diatomaceous earth is divided into two parts, one part is reacted with the hydrolysate at 50~65℃ for 30~60min; then the other part of diatomaceous earth is added, and the temperature is raised to 75~85℃ for 60~120min.

[0019] At 50-65℃, the first batch of added diatomaceous earth reacts with the hydrolysate. The relatively low reaction temperature and sufficient reaction time promote the orderly and dense grafting of oligomeric siloxanes on its outer surface and at the entrance of large pores, forming a firmly bonded aminated surface layer. In the second stage, a second batch of diatomaceous earth is added and the temperature is raised to 75-85℃. The higher temperature accelerates the diffusion and grafting of the remaining oligomers into the deep pores of the first batch of diatomaceous earth, and also allows it to react rapidly with the fresh surface of the second batch of diatomaceous earth. At the same time, it promotes the cross-linking between the grafted segments, thus forming a gradient structure with gradually changing grafting density and bonding strength from the outside to the inside at different spatial scales of the diatomaceous earth. The above gradient structure enables the subsequently loaded functional active components to form a distribution state with different adsorption intensities on the solid carrier, providing a structural basis for realizing their time-sequential release and long-term effect when heated during construction.

[0020] Furthermore, the particle size of the diatomaceous earth after sieving is 75~300μm.

[0021] The above-mentioned particle size range gives diatomaceous earth a sufficient specific surface area to load functional active components, while its moderate particle size prevents uneven dispersion or sedimentation and segregation among aggregates caused by excessively large particle size.

[0022] This invention also provides a method for preparing a warm-stirring regenerator, comprising: A1 mixes pretreated waste engine oil with aromatic supplement oil to form a regenerator oil phase; antioxidants and toughening agents are added to the regenerator oil phase and stirred evenly to obtain a compound waste engine oil regenerator; through this step, the functional components are fully dispersed and compatible in the oil phase, and after cooling, a compound waste engine oil regenerator with uniform properties is obtained, providing a stable foundation for the subsequent integration of warm mixing function.

[0023] A2 heats the compound waste oil regenerator to 115~125℃, then adds stearamide, keeps warm and stirs evenly to obtain a warm-mix regenerator semi-finished product; in this step, stearamide is added to the molten compound waste oil regenerator so that the stearamide can be mixed evenly.

[0024] A3 involves controlling the temperature of the warm-mix regenerator semi-finished product to 110-120℃, then adding a solid carrier, maintaining the temperature and stirring for 40-60 minutes, and cooling to room temperature to obtain the final product. Alternatively, the paste-like semi-finished product can be heated to 110-120℃, a temperature slightly higher than the melting point of stearamide, which is beneficial for its molecular movement. Adding the solid carrier under these conditions and continuously stirring for 40-60 minutes not only allows the functional active components to physically impregnate and fill the pores of the solid carrier, but also provides sufficient thermodynamic conditions and reaction time for hydrogen bonding between the amide groups of stearamide and the amino groups on the surface of the solid carrier. This allows the functional active components to form a chemically anchored gradient adsorption structure on the solid carrier.

[0025] Further, the pretreatment method in step A1 is as follows: filter the waste engine oil and heat it at 140~150℃ to dehydrate it, and then cool it down to 55~65℃.

[0026] Heating to 140~150℃ for dehydration, which is significantly higher than the boiling point of water, can effectively remove free water and emulsified water entrained in waste engine oil. At the same time, this temperature has not yet reached the typical flash point of light base oil components in waste engine oil. After dehydration, the temperature is reduced to 55~65℃, within which the viscosity of waste engine oil is suitable for efficient mechanical stirring.

[0027] Furthermore, the method for adding antioxidants and toughening agents is as follows: Heat the oil phase of the regenerator to 95~105℃, keep it warm, add the antioxidant, stir evenly, then add the toughening agent and stir evenly.

[0028] Adding the antioxidant first and stirring thoroughly allows it to distribute evenly in the relatively pure oil phase, pre-establishing an antioxidant protection network. Then, a toughening agent is added to this homogeneous system to avoid the steric hindrance that the toughening agent might cause due to the diffusion of antioxidant molecules.

[0029] The technical solution of this invention can achieve the following technical effects: This step involves adding diatomaceous earth in batches and carrying out a multi-step reaction at different temperatures to achieve gradient grafting of silanes on the surface of diatomaceous earth. A strong chemical reaction zone is formed on the surface of diatomaceous earth and at the pore inlet, while a weak physical reaction zone is formed on the inner wall of the pores. The compounded waste oil regenerator in the weak physical reaction zone can be quickly desorbed under low heat drive, achieving the replenishment of light oils and rapid lubrication of aged asphalt in the early stage. The stearamide in the strong chemical reaction zone requires higher heat energy to desorb, thereby achieving slow and continuous release in the later stage and providing a long-lasting warm-mix viscosity reduction effect. After the functional active components are released, the solid carrier still retains some unused amino groups. These amino groups can act as polar reaction sites in the asphalt mastic, continuously interacting with the acidic oxidation products in the aged asphalt, thereby improving the adhesion of the asphalt aggregate interface at the microscopic level and providing a basis for improving the long-term water damage resistance of the mixture. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic flowchart of the warm-stirring regenerator preparation method of the present invention. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application.

[0035] Example 1: This embodiment provides a method for preparing a warm-stirring regenerator, wherein the raw materials include: Functional active ingredients: The total mass is 77g, which consists of the following two components: Compound waste oil regeneration agent: 53.9g, which is composed of the following components by weight: 100 parts of pretreated waste oil, 40 parts of G23 aromatic oil, 3 parts of antioxidant BHT, and 8 parts of toughening agent DOP; stearamide: 23.1g. The solid carrier weighs 23g and is prepared by the following method: S1 processes diatomaceous earth raw materials by crushing, screening and drying to obtain surface-activated diatomaceous earth; Specifically, industrial diatomaceous earth raw materials are weighed, mechanically crushed and sieved, and particles with a diameter of about 180μm are taken and placed in an oven to dry at 105℃ for 2 hours to obtain surface-activated diatomaceous earth. S2 adds an aminosilane coupling agent to an alcohol solvent, and under ice-water bath cooling and inert gas protection, adds a catalytic amount of water, and stirs and hydrolyzes at 0~10℃ for 10~30 min to obtain a hydrolysate mainly composed of oligomeric siloxanes. Specifically, in a reaction flask equipped with a stirrer, thermometer, and nitrogen delivery tube, 100 mL of anhydrous ethanol was added. Under the protection of an ice-water bath and continuous nitrogen flow, 5.0 g of KH-550 was added, followed by the slow addition of 5 mL of an ethanol solution containing 0.5 g of deionized water. The system temperature was maintained at 5 ± 2 °C, and the reaction was stirred at a rate of 500 r / min for 20 min to obtain a clear and transparent oligomeric siloxane hydrolysate.

[0036] S3 mixes surface-activated diatomaceous earth with hydrolysate in batches and carries out a multi-step reaction under different temperature conditions; Specifically, 25g of the first portion of diatomaceous earth was added to the above hydrolysate, the system was gradually heated to 55°C, and stirred at 400r / min for 45min at this temperature. While stirring, add a second portion of 25g of diatomaceous earth to the reaction system, raise the system temperature to 80℃, and continue the reaction at this temperature for 90min.

[0037] After the S4 reaction is completed, the solid product is separated, washed and dried to obtain the solid support. Specifically, after the reaction was completed, the mixture was filtered under reduced pressure, the resulting solid was washed three times with anhydrous ethanol, and then the solid product was dried in a vacuum drying oven at 80°C to constant weight. After grinding, a solid support was obtained.

[0038] The preparation methods of warm-stir regenerator include: A1 mixes pretreated waste engine oil with aromatic supplement oil to form a regenerator oil phase; antioxidants and toughening agents are added to the regenerator oil phase and stirred evenly to obtain a compound waste engine oil regenerator; Specifically, take 100g of waste engine oil, filter it through a 0.075mm sieve, and place it in a heated stirrer; raise the oil temperature to 145℃ and maintain it for 30 minutes to dehydrate it, then stop heating and allow the oil temperature to drop naturally to 60℃; add 40g of G23 aromatic oil to the cooled waste engine oil, and stir at 500r / min for 10 minutes at room temperature to form a uniform regenerator oil phase; heat the above oil phase to 100℃, add 3.0g of antioxidant BHT under the heat preservation condition, and stir at 500r / min for 20 minutes until completely dissolved; maintain the temperature at 100℃, add 8.0g of toughening agent DOP to the system, and stir at 300r / min for 5 minutes to mix it evenly.

[0039] A2 heats the compounded waste engine oil regenerator to 115~125℃, then adds stearamide, keeps warm and stirs evenly to obtain a warm-mix regenerator semi-finished product; Specifically, weigh 53.9g of the compound waste oil regenerator prepared above, heat it to 120℃, and slowly add 23.1g of stearamide powder at a stirring rate of 500r / min. After all the stearamide has been added, continue to keep it warm and stir at 120℃ for 30min until a homogeneous and stable liquid mixture is formed.

[0040] A3 involves controlling the temperature of the warm-mix regenerator semi-finished product to 110~120℃, then adding a solid carrier, keeping it warm and stirring for 40~60 minutes, and cooling it to room temperature to obtain the final product. Specifically, the semi-finished warm-mix regenerator is cooled to 115°C, and 23.0g of solid carrier is slowly added while stirring at 400r / min. The mixture is then kept at 115°C and stirred for another 50 minutes, followed by natural cooling to room temperature. After cooling, the mixture solidifies into easily breakable blocky solids, which is the finished solid warm-mix regenerator. This finished product can be further pulverized into free-flowing powder for use.

[0041] Example 2: This embodiment provides a method for preparing a warm-stirring regenerator, wherein the raw materials include: Functional active ingredients: The total mass is 80g, which consists of the following two components: Compound waste oil regeneration agent: 56g, which is composed of the following by weight: 100 parts of pretreated waste oil, 35 parts of G23 aromatic oil, 4 parts of antioxidant BHT, 6 parts of toughening agent DOP; Stearamide: 24g. The solid carrier is 20g, and its preparation method is as follows: S1 processes diatomaceous earth raw materials by crushing, screening and drying to obtain surface-activated diatomaceous earth; Specifically, industrial diatomaceous earth raw materials are weighed, mechanically crushed and sieved, and particles with a diameter of about 100μm are taken and placed in an oven to dry at 105℃ for 2 hours to obtain surface-activated diatomaceous earth. S2 adds an aminosilane coupling agent to an alcohol solvent, and under ice-water bath cooling and inert gas protection, adds a catalytic amount of water, and stirs and hydrolyzes at 0~10℃ for 10~30 min to obtain a hydrolysate mainly composed of oligomeric siloxanes. Specifically, in a reaction flask equipped with a stirrer, thermometer, and nitrogen delivery tube, 120 mL of anhydrous ethanol was added. Under the protection of an ice-water bath and continuous nitrogen flow, 6 g of KH-550 was added, followed by the slow addition of 5 mL of ethanol solution containing 0.5 g of deionized water. The system temperature was maintained at 2 ± 2 °C, and the reaction was stirred at a rate of 500 r / min for 25 min to obtain a clear and transparent oligomeric siloxane hydrolysate.

[0042] S3 mixes surface-activated diatomaceous earth with hydrolysate in batches and carries out a multi-step reaction under different temperature conditions; Specifically, 30g of the first portion of diatomaceous earth was added to the above hydrolysate, the system was gradually heated to 60°C, and stirred at 400r / min for 45min at this temperature. While stirring, add a second portion of 30g of diatomaceous earth to the reaction system, raise the system temperature to 78℃, and continue the reaction at this temperature for 90min.

[0043] After the S4 reaction is completed, the solid product is separated, washed and dried to obtain the solid support. Specifically, after the reaction was completed, the mixture was filtered under reduced pressure, the resulting solid was washed three times with anhydrous ethanol, and then the solid product was dried in a vacuum drying oven at 80°C to constant weight. After grinding, a solid support was obtained.

[0044] The preparation methods of warm-stir regenerator include: A1 mixes pretreated waste engine oil with aromatic supplement oil to form a regenerator oil phase; antioxidants and toughening agents are added to the regenerator oil phase and stirred evenly to obtain a compound waste engine oil regenerator; Specifically, 100g of waste engine oil is filtered through a 0.075mm sieve and placed in a heated stirrer. The oil temperature is raised to 148℃ and maintained for 30 minutes for dehydration. Then, heating is stopped, and the oil temperature is allowed to drop naturally to 58℃. 35g of G23 aromatic oil is added to the cooled waste engine oil, and the mixture is stirred at 500r / min for 12 minutes at room temperature to form a uniform regenerator oil phase. The oil phase is heated to 98℃, and 4.0g of antioxidant BHT is added under heat preservation conditions. The mixture is stirred at 500r / min for 20 minutes until completely dissolved. The temperature is maintained at 100℃, and 6.0g of toughening agent DOP is added to the system. The mixture is stirred at 300r / min for 5 minutes to ensure uniform mixing.

[0045] A2 heats the compounded waste engine oil regenerator to 115~125℃, then adds stearamide, keeps warm and stirs evenly to obtain a warm-mix regenerator semi-finished product; Specifically, weigh 56g of the compound waste oil regenerator prepared above, heat it to 118℃, and slowly add 24g of stearamide powder at a stirring rate of 500r / min. After all the stearamide has been added, continue to heat and stir at 118℃ for 30min until a homogeneous and stable liquid mixture is formed.

[0046] A3 involves controlling the temperature of the warm-mix regenerator semi-finished product to 110~120℃, then adding a solid carrier, keeping it warm and stirring for 40~60 minutes, and cooling it to room temperature to obtain the final product. Specifically, the semi-finished warm-mix regenerator is cooled to 112°C, and 20g of solid carrier is slowly added while stirring at 450r / min. The mixture is then kept at 112°C and stirred for another 55min, followed by natural cooling to room temperature. After cooling, the mixture solidifies into easily breakable blocky solids, which is the finished solid warm-mix regenerator. This finished product can be further pulverized into free-flowing powder for use.

[0047] Example 3: Unlike Example 1, the solid support was prepared using the following method: S1 Weigh industrial diatomaceous earth raw material, crush it mechanically and sieve it to obtain particles with a particle size of about 250μm. Place them in an oven and dry them at 115℃ for 2 hours to obtain surface-activated diatomaceous earth. In reaction flask equipped with a stirrer, thermometer and nitrogen delivery tube, 120 mL of anhydrous ethanol was added. Under the protection of nitrogen gas and cooling in an ice-water bath, 6 g of KH-550 was added. Then, 5 mL of ethanol solution containing 0.6 g of deionized water was slowly added dropwise. The system temperature was maintained at 6±2℃ and the reaction was stirred at 500 r / min for 25 min to obtain a clear and transparent oligomeric siloxane hydrolysate.

[0048] S3 added the first 30g of diatomaceous earth to the above hydrolysate, gradually heated the system to 60℃, and stirred the reaction at 350r / min for 45min at this temperature; While stirring, add a second portion of 30g of diatomaceous earth to the reaction system, raise the system temperature to 82℃, and continue the reaction at this temperature for 80min.

[0049] After the S4 reaction was completed, the mixture was filtered under reduced pressure. The resulting solid was washed three times with anhydrous ethanol. The solid product was then dried in a vacuum drying oven at 80°C until constant weight. After grinding, a solid support was obtained.

[0050] Comparative Example 1: Compared with Example 1, the difference of Comparative Example 1 is that its solid carrier is ordinary diatomaceous earth that has not been modified with aminosilane, and it is subjected to crushing, screening and drying treatment under the same conditions.

[0051] Comparative Example 2: Compared with Example 1, the difference of Comparative Example 2 is that in the preparation method of its solid carrier, step S3 is modified to: all 50g of surface-activated diatomaceous earth is added to the hydrolysate at one time, and the mixture is stirred and reacted at a single temperature of 75°C for 135min.

[0052] Comparative Example 3: Compared with Example 1, the difference in Comparative Example 3 is that the stearamide and other components in its functional active components are replaced by polyolefin wax-based warm mix agent.

[0053] The solid warm-mix recycling agents prepared in the examples and comparative examples were used to prepare AC-20 recycled asphalt mixtures containing 40% recycled asphalt pavement material at a dosage of 0.45%, and their key construction and road performance were tested. The performance test results are summarized in the table below: As shown in the table above, the high-temperature dynamic stability of the examples at lower compaction temperatures is significantly higher than that of Comparative Example 1, which requires compaction at higher temperatures. This indicates that Comparative Example 1, due to the lack of slow release, had its active components largely consumed or ineffective in the early stages of high-temperature mixing, resulting in insufficient lubrication in the later compaction stage, necessitating an increase in temperature. In contrast, the gradient structure of the examples ensures the continuous effect of stearamide, allowing the mixture to maintain good compactibility at lower temperatures and avoiding secondary aging and performance loss of asphalt caused by high temperatures.

[0054] The polyolefin wax-based warm mix additive used in Comparative Example 3 lacks specific interaction between its molecular structure and the amino groups on the surface of the solid carrier, resulting in its rapid and one-time release upon heating, relying entirely on physical adsorption. While this release method produces a strong instantaneous viscosity-reducing effect in the initial stage of mixing, leading to a lower compaction temperature reading, it also causes excessive softening of the asphalt mastic at high temperatures and a sharp drop in cohesion, directly weakening the stability of the mixture skeleton and resulting in a decrease in high-temperature dynamic stability. Furthermore, the non-polar wax component cannot participate in interfacial interactions through polar amide groups like stearamide, and its coating on the aggregate surface may weaken the adhesion between asphalt and aggregate. In addition, the carrier amino groups are physically coated by the wax film, making it difficult for them to be effectively exposed and interact with the acidic components of aged asphalt, all of which contribute to its worst water damage resistance among all groups.

[0055] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of the application as defined herein, and are to be considered as covering any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.

Claims

1. A warm-mix regenerator, characterized in that, The product comprises, by mass percentage, 70-85 wt% of functional active component and 15-30 wt% of solid support, wherein the functional active component is adsorbed onto the solid support; By weight percentage, the functional active components include: 60-80 wt% of compounded waste oil regenerator and 20-40 wt% of stearamide; By weight, the compounded waste engine oil regenerator comprises 100 parts waste engine oil, 30-50 parts aromatic supplement oil, 2-5 parts antioxidant, and 5-10 parts toughening agent; The solid carrier is modified diatomaceous earth with a gradient distribution of amino functional groups on its surface and within its pores.

2. The warm-stir regenerator according to claim 1, characterized in that, The aromatic supplement oil is G23 aromatic oil.

3. The warm-stir regenerator according to claim 1, characterized in that, The antioxidant is 2,6-di-tert-butyl-p-cresol.

4. The warm-stir regenerator according to claim 1, characterized in that, The toughening agent is diisooctyl phthalate.

5. The warm-stir regenerator according to claim 1, characterized in that, The method for preparing the solid support includes: S1 processes diatomaceous earth raw materials by crushing, screening and drying to obtain surface-activated diatomaceous earth; S2 adds an aminosilane coupling agent to an alcohol solvent, and under ice-water bath cooling and inert gas protection, adds a catalytic amount of water, and stirs and hydrolyzes at 0~10℃ for 10~30 min to obtain a hydrolysate mainly composed of oligomeric siloxanes. S3 The surface-activated diatomaceous earth is mixed with the hydrolysate in batches and subjected to a multi-step reaction under different temperature conditions; After the S4 reaction is completed, the solid product is separated, washed and dried to obtain the solid support.

6. The warm-stir regenerator according to claim 5, characterized in that, The specific method of S3 is as follows: the surface-activated diatomaceous earth is divided into two parts, one part is reacted with the hydrolysate at 50~65℃ for 30~60min; then the other part of diatomaceous earth is added, and the temperature is raised to 75~85℃ for 60~120min.

7. The warm-stir regenerator according to claim 5, characterized in that, The particle size of the diatomaceous earth after sieving is 75~300μm.

8. The method for preparing the warm-stir regenerator according to any one of claims 1 to 7, characterized in that, include: A1 mixes the pretreated waste engine oil with aromatic replenishment oil to form a regenerator oil phase; Antioxidant and toughening agent are added to the oil phase of the regenerator and stirred evenly to obtain the compound waste engine oil regenerator; A2 heats the compounded waste engine oil regenerator to 115~125℃, then adds stearamide, keeps warm and stirs evenly to obtain a warm-mix regenerator semi-finished product; A3. The semi-finished warm-mix regenerator is heated to 110~120℃, then the solid carrier is added, and the mixture is kept warm and stirred for 40~60 minutes. After cooling to room temperature, the product is obtained.

9. The method for preparing the warm-stirring regenerator according to claim 8, characterized in that, The pretreatment method in step A1 is as follows: filter the waste engine oil and heat it at 140~150℃ to remove water, and then cool it down to 55~65℃.

10. The method for preparing the warm-stirring regenerator according to claim 8, characterized in that, The method for adding the antioxidant and toughening agent is as follows: The regenerator oil phase is heated to 95~105℃, the antioxidant is added while maintaining the temperature, and the toughening agent is added after stirring evenly.

Images