Low-temperature-resistant high-modulus rubber asphalt and preparation method thereof

Abstract

The invention provides low-temperature-resistant high-modulus rubber asphalt and a preparation method thereof, and relates to the technical field of rubber asphalt, and preparation raw materials of the low-temperature-resistant high-modulus rubber asphalt comprise the following components: matrix asphalt, rubber powder, a desulfurizer, a free radical type thermal initiation crosslinking agent, a reinforcing agent, a coupling agent, a flexibilizer, a viscosity reducer and an auxiliary agent. According to the low-temperature-resistant high-modulus rubber asphalt provided by the invention, the ductility at 5 DEG C is greater than 30cm, the maximum breaking flexural-tensile strain of a mixture at-10 DEG C is greater than 4000 mu epsilon, the dynamic modulus of the mixture at 15 DEG C is greater than 15000MPa, and the high-temperature performance and modulus of high-modulus asphalt concrete are not reduced while the crack resistance of the high-modulus asphalt concrete is helped to be improved. When being applied to pavement middle layer pavement, the pavement anti-cracking agent can improve the anti-cracking performance of the whole pavement structure, reduce the pavement maintenance cost and improve the driving safety.

Description

Technical Field

[0001] This invention relates to the field of rubber asphalt technology, and in particular to a low-temperature resistant, high-modulus rubber asphalt and its preparation method. Background Technology

[0002] High-modulus asphalt concrete is a high-performance asphalt mixture designed with special materials or processes. Its core characteristic is high modulus (dynamic modulus at 15℃ ≥ 14,000 MPa), which can significantly improve the pavement's resistance to rutting, fatigue, and durability, making it particularly suitable for heavy-duty traffic pavements and high-temperature environments in summer. High-modulus asphalt is the key to the strength formation and performance guarantee of high-modulus asphalt concrete.

[0003] Currently, there are three main methods for preparing high-modulus asphalt: 1. Modification of low-grade hard asphalt; 2. Modification of natural asphalt; 3. Modification by admixture of high-modulus agents. Among these three methods, hard asphalt is often prepared using oxidation or solvent removal processes, resulting in high hardness, but often exhibiting poor low-temperature crack resistance and significantly insufficient fatigue resistance. Modified natural asphalt is often formulated using lake asphalt, rock asphalt, etc., which possess high resistance to deformation and aging. However, natural asphalt has high viscosity, making processing difficult, and requires large admixture amounts, leading to high costs. While high-modulus agents themselves have high modulus, their compatibility with the base asphalt is poor. Directly adding high modulus agents to asphalt can easily lead to storage segregation problems. Currently, they are mostly added directly to the mixture. However, the mixing time of the mixture is relatively short, and high modulus agents do not have the ability to dissolve and disperse rapidly at the mixing temperature of the mixture, which often results in unstable performance of the mixture. At the same time, simply adding high modulus agents to the mixture only increases the modulus of asphalt concrete, but does not improve the low-temperature crack resistance of concrete. Therefore, asphalt pavements with external high modulus agents have the potential for low-temperature cracking.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] One of the objectives of this invention is to provide a low-temperature resistant, high-modulus rubber asphalt, so as to at least solve one of the technical problems existing in the prior art.

[0006] The second objective of this invention is to provide a method for preparing low-temperature resistant, high-modulus rubber asphalt.

[0007] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: In a first aspect, the present invention provides a low-temperature resistant, high-modulus rubber asphalt, the raw materials for which are prepared include the following components: base asphalt, rubber powder, desulfurizer, free radical thermally initiated crosslinking agent, reinforcing agent, coupling agent, toughening agent, viscosity reducer and additives.

[0008] Furthermore, the rubber powder includes one or more of the following: waste tire rubber powder, waste rubber shoe rubber powder, industrial vulcanized rubber scraps powder, and waste conveyor belt rubber powder; Preferably, the particle size of the waste tire rubber powder includes at least one of 40 mesh, 60 mesh, and 80 mesh; Preferably, the desulfurizing agent comprises dibenzoylamino diphenyl disulfide; Preferably, the free radical thermally initiated crosslinking agent comprises triallyl isocyanurate; Preferably, the reinforcing agent comprises silica; Preferably, the coupling agent comprises a silane coupling agent; Preferably, the toughening agent comprises solution-polymerized styrene-butadiene rubber; Preferably, the viscosity reducer comprises at least one of vinyl bis-stearamide, ethylene bis-oleamide, and ethylene bis-lauramide.

[0009] Furthermore, the additives include: compatibilizers, softening desulfurization regenerators, crosslinking promoters, and thickening agents.

[0010] Furthermore, the compatibilizer includes aromatic oils; Preferably, the softening desulfurization regenerator comprises naphthenic oil; Preferably, the crosslinking agent comprises nano-zinc oxide; Preferably, the thickening agent comprises petroleum resin; Preferably, the petroleum resin includes at least one of C9 petroleum resin, coumarone resin, and terpene resin.

[0011] Furthermore, the raw materials for preparing the low-temperature resistant high-modulus rubber asphalt include, by weight, 50-65 parts of base asphalt, 10-30 parts of rubber powder, 0.5-4 parts of desulfurizer, 0.5-3 parts of free radical thermally initiated crosslinking agent, 1-3 parts of reinforcing agent, 0.1-2 parts of coupling agent, 1-5 parts of viscosity reducer, 3-12 parts of toughening agent, 1-10 parts of compatibilizer, 1-5 parts of softening desulfurization regenerator, 0.5-2 parts of crosslinking promoter and 1-8 parts of viscosity enhancer.

[0012] Secondly, the present invention provides a method for preparing low-temperature resistant high-modulus rubber asphalt, comprising the following steps: (a) Rubber powder is added to the base asphalt in a fluid state to form rubber asphalt; (b) Add a desulfurizing agent to the rubber asphalt to perform desulfurization and decrosslinking; (c) Add a free radical-type thermally initiated crosslinking agent to perform crosslinking; (d) Add reinforcing agents and coupling agents to perform chemical coupling; (e) Add viscosity reducer and toughening agent to obtain the low-temperature resistant high-modulus rubber asphalt.

[0013] Furthermore, in step (a), the base asphalt is heated and melted to a fluid state at a temperature of 160-180°C, and then rubber powder and compatibilizer are added and the temperature is raised to 170-190°C. Preferably, in step (b), the desulfurizing agent and the softening desulfurization regenerator are added at a temperature of 180-190°C and stirred for 30-60 minutes.

[0014] Furthermore, in step (c), a free radical thermal initiator and a crosslinking promoter are added at a temperature of 180-190°C.

[0015] Furthermore, in step (d), the reinforcing agent and coupling agent are added at a temperature of 180-190℃ and stirred for 40-60 minutes.

[0016] Furthermore, in step (e), a viscosity reducer, a toughening agent, and a viscosity-enhancing agent are added at a temperature of 170-180°C; Preferably, in step (e), a viscosity reducer and a viscosity-enhancing agent are added, followed by a toughening agent.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The low-temperature resistant, high-modulus rubber asphalt provided by this invention introduces a desulfurizing agent to de-crosslink the rubber powder, allowing it to fully swell and uniformly disperse in the asphalt system, significantly improving compatibility and stability. Subsequently, a free-radical thermally initiated crosslinking agent is used to trigger secondary chemical crosslinking under heating conditions, constructing a high-strength three-dimensional network structure, effectively improving the material modulus and high-temperature performance. Simultaneously, the synergistic effect of reinforcing agents and coupling agents further enhances the system's anti-aging ability and thermal storage stability. Furthermore, the addition of toughening agents significantly improves the low-temperature ductility and crack resistance of the rubber asphalt, effectively addressing the problem of brittleness in high-modulus asphalt. Viscosity reducers lower the system's 135℃ Brinell viscosity, improving workability and component dispersion uniformity, helping to reduce low-temperature shrinkage stress concentration, and indirectly improving low-temperature performance stability. Tackifying agents increase the asphalt's 60℃ dynamic viscosity, significantly improving the asphalt's adhesion to aggregates. The synergistic effect of these three factors significantly improves the low-temperature ductility and crack resistance of rubberized asphalt, while also enhancing high-temperature fluidity, component dispersion uniformity, and high-temperature viscosity. This effectively solves the technical problems of low-temperature brittleness and insufficient aggregate adhesion caused by the increased rigidity of high-modulus asphalt. The overall formulation of this invention, through a multi-stage chemical modification mechanism, achieves high modulus while maintaining excellent low-temperature crack resistance, thus solving the technical problems of poor low-temperature crack resistance and easy segregation in traditional high-modulus asphalt.

[0018] The method for preparing low-temperature resistant, high-modulus rubber asphalt provided by this invention achieves multi-level synergistic modification of rubber asphalt through sequential steps of desulfurization and decrosslinking, chemical crosslinking, chemical coupling interface enhancement, and performance regulation. First, the rubber powder in the base asphalt is desulfurized by an agent to break the original crosslinking network, significantly improving dispersibility and compatibility. Then, a high-strength three-dimensional chemical crosslinking structure is reconstructed using a free-radical thermally initiated crosslinking agent, effectively improving the material's modulus and thermal stability. Next, the synergistic effect of reinforcing agents and coupling agents achieves interfacial chemical bonding and secondary reinforcement, further enhancing anti-aging properties. Finally, viscosity reducers and toughening agents are introduced to lower the application viscosity while improving low-temperature crack resistance. In the overall process, each step works synergistically, resulting in rubber asphalt with excellent comprehensive properties including high modulus and low-temperature resistance. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 The present invention provides a process flow for preparing low-temperature resistant, high-modulus rubber asphalt. Detailed Implementation

[0021] Unless otherwise defined herein, the scientific and technical terms used in conjunction with this invention shall have the meanings commonly understood by one of ordinary skill in the art. The meaning and scope of terms shall be clear; however, in any case of potential ambiguity, the definitions provided herein shall prevail over any dictionary or foreign definitions. In this application, unless otherwise stated, the use of "or" means "and / or". Furthermore, the use of the term "comprising" and other forms is non-limiting.

[0022] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The first aspect of the present invention provides a low-temperature resistant, high-modulus rubber asphalt, the raw materials for which are prepared include the following components: base asphalt, rubber powder, desulfurizer, free radical thermally initiated crosslinking agent, reinforcing agent, coupling agent, toughening agent, viscosity reducer and additives.

[0024] This invention addresses the problems of high-modulus asphalt currently on the market by proposing a low-temperature resistant high-modulus rubber asphalt. It solves the problem of poor low-temperature performance of traditional high-modulus asphalt, which makes the mixture prone to cracking at low temperatures. At the same time, it uses special additives and modifiers, as well as a multi-stage synergistic modification method to help improve the poor aging resistance and poor thermal storage stability of traditional rubber asphalt, thereby ensuring the excellent comprehensive performance of high-modulus rubber asphalt.

[0025] High-modulus asphalt is key to the strength formation and performance assurance of high-modulus asphalt concrete. It is an important material for solving rutting, shoving, and shoving problems on heavy-load roads, as well as for durable asphalt pavements. Traditional high-modulus asphalt, while solving rutting problems, cannot simultaneously address low-temperature performance, leading to road surface cracking in winter and low-temperature environments. The low-temperature resistant high-modulus rubber asphalt provided by this invention has a ductility >30cm at 5℃, a maximum breaking flexural strain >4000με in the mixture at -10℃, and a dynamic modulus >15000MPa in the mixture at 15℃. This helps improve the crack resistance of high-modulus asphalt concrete without compromising its high-temperature performance and modulus. When used in the middle and surface layers of road paving, it can improve the overall crack resistance of the pavement structure, reduce road maintenance costs, and improve driving safety. In addition, compared with traditional high-modulus asphalt modification technologies, this invention also solves the shortcomings of segregation of thermal storage modifiers and poor aging resistance, greatly increasing the performance stability of the material and thus improving pavement durability.

[0026] This invention involves adding a desulfurizing agent to rubber asphalt. Through a desulfurization and de-crosslinking reaction, the CS and SS bonds of the rubber powder break, separating the crosslinking effect between carbon black and rubber powder. This allows the rubber powder to fully swell and stably disperse in the matrix asphalt. Simultaneously, a free radical-type thermally initiated crosslinking agent, triallyl isocyanurate, is added for secondary crosslinking, ensuring system stability and improving modulus. A reinforcing agent, silica, is added, and a silane coupling agent undergoes secondary reinforcement through chemical coupling, further improving the modulus. Finally, a viscosity reducer and a toughening agent are added to reduce viscosity and improve low-temperature performance, respectively. The final product exhibits excellent low-temperature resistance (flexible without cracking at -20℃, ductility ≥30cm at 5℃), excellent complex shear modulus (complex shear modulus ≥100,000 Pa at 60℃), and stability without segregation after thermal storage (softening point ≤1℃ after 48h thermal storage segregation). Furthermore, the chemical coupling effect between the reinforcing agent silica and the rubber powder prevents chain breakage during thermal storage aging of the rubber asphalt, significantly improving its aging resistance.

[0027] It should be noted that, in this invention, primary crosslinking refers to the three-dimensional network structure formed by vulcanization during the original manufacturing process of rubber powder, i.e., the rubber powder itself is already crosslinked vulcanized rubber. In this invention, primary crosslinking is first disrupted, and then a more stable secondary crosslinking is constructed. In this invention, primary reinforcement refers to the reinforcing effect of the carbon black filling system contained in the rubber powder during the original production process on the rubber matrix, i.e., it is completed before the rubber powder is used as a raw material. This invention not only utilizes the primary reinforcement effect brought by the original carbon black in the rubber powder, but also constructs a secondary reinforcement network based on chemical coupling in the active system after desulfurization and decrosslinking by introducing silica and silane coupling agent, realizing the reconstruction of the reinforcement structure and performance upgrade, and significantly improving the modulus, thermal stability and anti-aging ability of rubber asphalt.

[0028] In this invention, the base asphalt, as the main base material in the formulation, is selected from either Sinopec Zhenhai Refining & Chemical 70# road petroleum asphalt or Shandong Jingbo Petrochemical 70# road petroleum asphalt.

[0029] In some preferred embodiments, the rubber powder includes one or more of waste tire rubber powder, waste rubber shoe rubber powder, industrial vulcanized rubber scraps powder, and waste conveyor belt rubber powder, which are used to improve the high and low temperature performance, elastic recovery, modulus and other physical properties of the base asphalt.

[0030] Preferably, the desulfurizing agent comprises dibenzoylamino diphenyl disulfide. The desulfurizing agent, also known as a desulfurizing and decrosslinking agent, is used to break the CS and SS crosslinking chemical bonds in rubber powder, thereby ensuring the desulfurized rubber powder is fully compatible with asphalt.

[0031] Preferably, the free radical thermally initiated crosslinking agent includes triallyl isocyanurate, which enables secondary crosslinking of rubber asphalt through a chemical reaction, thereby enhancing the modulus, strength, and other properties of the asphalt.

[0032] In this invention, triallyl isocyanurate is added to rubber asphalt, causing secondary crosslinking and thus increasing the modulus. This secondary crosslinking is a chemical crosslinking process, characterized by rapid reaction, resistance to secondary bond breakage, and no decrease in modulus with increasing reaction time. Triallyl isocyanurate is a crosslinking agent that decomposes under heating, producing isocyanate ions and free radicals. The isocyanate ions react with the double bonds in the rubber powder, while the free radicals participate in subsequent crosslinking reactions. This continuous reaction ultimately forms a crosslinked structure. After desulfurization and decomposition of crosslinking bonds in the rubber asphalt, the addition of triallyl isocyanurate induces secondary crosslinking, significantly increasing the modulus of the rubber asphalt. Furthermore, the new crosslinked structure is resistant to secondary bond breakage under heat, and the modulus does not decrease with increasing heating time.

[0033] Preferably, the reinforcing agent includes silica; the reinforcing agent is also called a reinforcing and anti-aging additive, which improves the resistance of rubber asphalt to thermo-oxidative aging, thermal storage stability and modulus.

[0034] Preferably, the coupling agent includes a silane coupling agent, which plays a coupling role, helps to make the silica and rubber asphalt more stable and compatible, and improves the modulus of asphalt through chemical cross-linking reaction.

[0035] In this invention, a silane coupling agent and silica are added. The coupling agent enables the silica to chemically couple with the rubber powder, enhancing the aging resistance and thermal stability of rubber asphalt. Silica is a nanoscale inorganic material with high specific surface area and strong surface activity, mainly composed of SiO2. Its reinforcing effect is significant; adding it to asphalt can replace carbon black for reinforcement and resistance to thermo-oxidative aging. Because its specific surface area is larger than carbon black but its density is lower, it disperses more stably in asphalt and is less prone to segregation. Simultaneously, silica possesses highly reactive silanol groups. Adding a silane coupling agent allows for the formation of strong Si-O-Si covalent bonds. Furthermore, the organic functional groups at the other end of the coupling agent can cross-link with the rubber molecular chains in the rubber powder, increasing the molecular weight of the system, making its chemical properties more stable, and the new molecular structure less susceptible to degradation by thermo-oxidative forces, thus greatly enhancing its aging resistance.

[0036] The toughening agent includes solution-polymerized styrene-butadiene rubber, which is used to improve the low-temperature performance and elastic recovery of asphalt.

[0037] The viscosity reducer includes at least one of vinyl bis-stearamide, ethylene bis-oleamide, and ethylene bis-lauramide, which reduces the viscosity of rubber asphalt at 180°C.

[0038] In some preferred embodiments, the additives include: compatibilizers, softening desulfurization regenerators, crosslinking promoters, and thickening agents.

[0039] In some preferred embodiments, the compatibilizer includes aromatic oils, which are used to improve the compatibility of the various phases of the system and its thermal storage stability.

[0040] Preferably, the softening desulfurization regenerator includes naphthenic oil, which is used to soften the rubber powder and accelerate the desulfurization and bond breaking speed of the rubber powder.

[0041] Preferably, the crosslinking agent includes nano zinc oxide, which is used to accelerate and promote the secondary crosslinking reaction of rubber powder, helping to rapidly increase the modulus of asphalt.

[0042] Preferably, the thickening agent includes petroleum resin, which is used to improve the high-temperature performance of asphalt, the compatibility of each component, and increase the dynamic viscosity of asphalt at 60°C.

[0043] Preferably, the petroleum resin includes at least one of C9 petroleum resin, coumarone resin, and terpene resin.

[0044] In some preferred embodiments, the raw materials for preparing the low-temperature resistant high-modulus rubber asphalt, based on a total of 100 parts, include, by weight: 10-30 parts rubber powder, 0.5-4 parts desulfurizer (preferably dibenzoylamino diphenyl disulfide), 0.5-3 parts free radical thermal initiating crosslinking agent (preferably triallyl isocyanurate), 1-3 parts reinforcing agent (preferably silica), 0.1-2 parts coupling agent, 1-5 parts viscosity reducer (vinyl bis-stearamide EBS), 3-12 parts toughening agent (solution-polymerized styrene-butadiene rubber SSBR), 1-10 parts compatibilizer (aromatic oil TC-24), 1-5 parts softening desulfurization regenerator (naphthenic oil KN-4006), 0.5-2 parts crosslinking promoter (nano zinc oxide), 1-8 parts tackifier (petroleum resin), and the balance being the base asphalt.

[0045] Of which, taking the total number of parts of low-temperature resistant high-modulus rubber asphalt as 100 parts, the amount of base asphalt added is preferably 50-65 parts, for example, 50 parts, 55 parts, 60 parts, 65 parts, etc.; more preferably 51-65 parts. In this case, with a total of 100 parts of low-temperature resistant high-modulus rubber asphalt, the amount of rubber powder added is 10-30 parts, for example, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, etc.; more preferably 14-23 parts. In this case, based on a total of 100 parts of low-temperature resistant high-modulus rubber asphalt, the amount of desulfurizer added is 0.5-4 parts, for example, 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, etc.; more preferably 1-2 parts. In this embodiment, based on a total of 100 parts of low-temperature resistant high-modulus rubber asphalt, the amount of free radical thermally initiated crosslinking agent added is 0.5-3 parts, for example, 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, etc.; more preferably 1-2 parts. In this case, based on a total of 100 parts of low-temperature resistant high-modulus rubber asphalt, the amount of reinforcing agent added is 1-3 parts, for example, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, etc.; more preferably 2-3 parts. In this embodiment, based on a total of 100 parts of low-temperature resistant high-modulus rubber asphalt, the amount of coupling agent added is 0.1-2 parts, for example, it can be 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2 parts, etc.; more preferably, it is 0.3-1.3 parts. In this case, based on a total of 100 parts of low-temperature resistant high-modulus rubber asphalt, the amount of viscosity reducer added is 1-5 parts, for example, it can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, etc.; more preferably 2-3 parts. In this case, with a total of 100 parts of low-temperature resistant high-modulus rubber asphalt, the amount of toughening agent added is 3-12 parts, for example, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, etc.; more preferably 4-8 parts. In this case, based on a total of 100 parts of low-temperature resistant high-modulus rubber asphalt, the amount of compatibilizer added is 1-10 parts, for example, it can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.; more preferably 3-6 parts. In this case, with a total of 100 parts of low-temperature resistant high-modulus rubber asphalt, the amount of softening desulfurization regenerator added is 1-5 parts, for example, it can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, etc.; more preferably 2-3 parts. In this case, taking the total number of parts of low-temperature resistant high-modulus rubber asphalt as 100 parts, the amount of crosslinking agent added is 0.5-2 parts, for example, it can be 0.5 parts, 1 part, 1.5 parts, 2 parts, etc. In this case, based on a total of 100 parts of low-temperature resistant high-modulus rubber asphalt, the amount of tackifier added is 1-8 parts, for example, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, etc.; more preferably 2-6 parts.

[0046] A second aspect of this invention provides a method for preparing low-temperature resistant, high-modulus rubber asphalt, comprising the following steps: (a) Rubber powder is added to the base asphalt in a fluid state to form rubber asphalt; (b) Add a desulfurizing agent to the rubber asphalt to perform desulfurization and decrosslinking; (c) Add a free radical-type thermally initiated crosslinking agent to perform crosslinking; (d) Add reinforcing agents and coupling agents to perform chemical coupling; (e) Add viscosity reducer and toughening agent to obtain the low-temperature resistant high-modulus rubber asphalt.

[0047] like Figure 1As shown, this invention replaces the original physical blending modification process (mixing-swelling) of high-modulus asphalt and rubber asphalt with a novel high-modulus rubber asphalt production process of desulfurization degradation-secondary crosslinking-secondary reinforcement-viscosity reduction and toughening to produce low-temperature resistant high-modulus rubber asphalt. Traditional high-modulus asphalt and rubber asphalt are modified by physical blending of modifiers with asphalt. Through the slow swelling and dispersion of the modifier in the asphalt, the modifier becomes compatible with the asphalt. However, this modification scheme does not allow the modifier to fully integrate with the asphalt, nor does it produce any chemical changes. Therefore, the modifier is prone to precipitation, and the low-temperature crack resistance of the asphalt is also poor. This invention employs a novel chemical modification process (desulfurization degradation—secondary crosslinking—secondary reinforcement—viscosity reduction and toughening) in four steps to prepare a new type of high-modulus rubber asphalt. A desulfurizing agent breaks the crosslinking bonds in the rubber powder, which then swells and fully dissolves in the asphalt. A crosslinking agent is then added for secondary crosslinking to increase the asphalt modulus. Reinforcing agents and coupling agents are added for secondary reinforcement to improve anti-aging properties. Finally, viscosity-reducing and toughening agents are added to produce a low-temperature resistant, high-modulus rubber asphalt, thus solving the problem of poor low-temperature crack resistance in high-modulus rubber asphalt.

[0048] In some preferred embodiments, in step (a), the base asphalt is heated and melted to a fluid state at a temperature of 160-180°C (e.g., 160°C, 165°C, 170°C, 175°C, 180°C, etc.), and then rubber powder and compatibilizer are added and the temperature is raised to 170-190°C (e.g., 170°C, 175°C, 180°C, 185°C, 190°C, etc.). Preferably, in step (b), the desulfurizing agent and the softening desulfurization regenerator are added at a temperature of 180-190℃ (e.g., 180℃, 185℃, 190℃, etc.), and stirred for 30-60 minutes, for example, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, etc.

[0049] In some preferred embodiments, in step (c), a free radical thermal initiator and a crosslinking promoter are added at a temperature of 180-190°C (e.g., 180°C, 185°C, 190°C, etc.).

[0050] In some preferred embodiments, in step (d), the reinforcing agent and coupling agent are added at a temperature of 180-190°C (e.g., 180°C, 185°C, 190°C, etc.) and stirred for 40-60 minutes.

[0051] In some preferred embodiments, in step (e), a viscosity reducer, a toughening agent, and a viscosity-enhancing agent are added at a temperature of 170-180°C (e.g., 170°C, 175°C, 180°C, etc.). Preferably, in step (e), a viscosity reducer and a viscosity-enhancing agent are added, followed by a toughening agent.

[0052] In this invention, during the later stages of preparation, a viscosity reducer, vinyl bis-stearamide, and a thickening agent, petroleum resin, are added to adjust the rheological properties of the system: the former reduces the application viscosity at 180°C, improving processing fluidity; the latter increases the dynamic viscosity and cohesive strength at 60°C, enhancing high-temperature stability. Subsequently, solution-polymerized styrene-butadiene rubber (SSBR) is added as a toughening agent, achieving uniform dispersion and full swelling within a suitable viscosity window, thus balancing the low-temperature crack resistance and overall structural stability of the asphalt. This step-by-step control strategy effectively coordinates multiple performance requirements, including processability, high modulus, and low-temperature resistance.

[0053] In a preferred embodiment of the present invention, the method for preparing the low-temperature resistant high-modulus rubber asphalt includes the following steps: Step 1: Prepare rubber asphalt: Heat 70# road petroleum asphalt to 160-180℃ until it is in a fluid state, add waste tire rubber powder and aromatic oil, heat to 170-190℃ and stir for 1 hour.

[0054] Step 2: Desulfurization and targeted decrosslinking: When the temperature of the rubber asphalt is maintained at 180-190℃, add naphthenic oil and dibenzoylamino diphenyl disulfide, stir for 30-60 minutes, and the desulfurization process is completed.

[0055] Step 3, Secondary cross-linking: When the temperature of the desulfurized rubber asphalt is maintained at 180-190℃, add triallyl isocyanurate and nano zinc oxide, stir for 60 minutes, and complete the secondary crosslinking.

[0056] Step 4: Chemical coupling, secondary reinforcement: After secondary crosslinking, the asphalt temperature is maintained at 180-190℃. Silica and silane coupling agent are added and stirred for 40-60 minutes.

[0057] Step 5: Reduce viscosity and toughen, completing the preparation: After secondary reinforcement, the temperature is reduced by 170-180℃, and the viscosity reducer vinyl bis-stearamide, petroleum resin, and SSBR are added. The mixture is stirred for 100-150 minutes to complete the preparation.

[0058] The present invention will be further illustrated by the following examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0059] The raw materials used in the following examples are: Base asphalt - selected from either Sinopec Zhenhai Refining & Chemical 70# road petroleum asphalt or Shandong Jingbo Petrochemical 70# road petroleum asphalt; 2,2'-Dibenzoylaminodiphenyldisulfide - Wuhan Kemike Biomedical Technology Co., Ltd. 2,2'-Dibenzoylaminodiphenyldisulfide 80 mesh; Waste tire rubber powder - 60 mesh waste car tire rubber powder; Triallyl isocyanurate - Shandong Shouhua Chemical Co., Ltd. Triallyl isocyanurate; Silica - Hubei Huifu Nanomaterials Co., Ltd. Fumed silica HL-380; Silane coupling agent - Maclean silane coupling agent KH550; Vinyl bis-stearamide - Donghao Chemical Co., Ltd. Vinyl bis-stearamide EBS; Solution-polymerized styrene-butadiene rubber (SSBR) - PetroChina Dushanzi Petrochemical; Aromatic oil - Shandong Taichang Petrochemical Technology Co., Ltd. rubber plasticizer TC-24 (product name); Naphthenic oil - Jinan Yuanyang Chemical Co., Ltd. Industrial naphthenic oil KN-4006; Nano Zinc Oxide - Fengyang Huijing Nano New Materials Technology Co., Ltd. 30nm Nano Zinc Oxide; Petroleum resin - C9 petroleum resin or coumarone resin or terpene resin.

[0060] Example 1 This embodiment provides a low-temperature resistant, high-modulus rubber asphalt, the raw materials for which include the following components: The composition of the following materials is as follows: 55 parts of Zhenhai Refining & Chemical 70# road petroleum asphalt, 2 parts of 2,2'-dibenzoylaminodiphenyl disulfide (80 mesh), 14 parts of waste tire rubber powder (60 mesh), 1 part of triallyl isocyanurate, 2 parts of fumed silica HL-380, 0.3 parts of KH550, 3 parts of EBS, 8 parts of SSBR, 5 parts of TC-24, 3 parts of KN-4006, 0.7 parts of nano zinc oxide, and 6 parts of C9 petroleum resin.

[0061] The preparation process of the low-temperature resistant high-modulus rubber asphalt is as follows: Step 1: Prepare rubber asphalt: 70# road petroleum asphalt was heated to 170℃ and melted to a fluid state. Waste tire rubber powder and aromatic oil TC-24 were added, and the temperature was raised to 190℃ and stirred for 1 hour at a stirring rate of 1200 r / min.

[0062] Step 2, Desulfurization and decrosslinking: While maintaining the stirring speed and keeping the asphalt temperature at 190℃, add naphthenic oil KN-4006 and dibenzoylamino diphenyl disulfide, stir for 60 minutes to complete the desulfurization process.

[0063] Step 3, Secondary cross-linking: While maintaining the stirring speed and the asphalt temperature at 190℃, add triallyl isocyanurate and nano zinc oxide, and stir for 60 minutes to complete the secondary crosslinking.

[0064] Step 4: Chemical coupling, secondary reinforcement: While maintaining the stirring speed and the asphalt temperature at 190℃, add HL-380 and KH550 fumed silica and stir for 40 minutes to complete the secondary reinforcement.

[0065] Step 5: Reduce viscosity and toughen, completing the preparation: Reduce the stirring speed to 800 r / min and the asphalt temperature to 180℃. Add the viscosity reducer vinyl bis-stearamide and C9 petroleum resin, stir for 30 min, add SSBR at 180℃, and stir for 2 h to complete the preparation.

[0066] Example 2 This embodiment provides a low-temperature resistant, high-modulus rubber asphalt, which differs from Embodiment 1 in that: The raw materials for preparing low-temperature resistant, high-modulus rubber asphalt include the following components: The composition of the following materials is as follows: 62 parts of Zhenhai Refining & Chemical 70# road petroleum asphalt, 2 parts of 2,2'-dibenzoylaminodiphenyl disulfide (80 mesh), 19 parts of waste tire rubber powder (60 mesh), 1 part of triallyl isocyanurate, 2 parts of fumed silica HL-380, 0.3 parts of KH550, 2 parts of EBS, 4 parts of SSBR, 3 parts of TC-24, 2 parts of KN-4006, 0.7 parts of nano zinc oxide, and 2 parts of coumarone resin.

[0067] Example 3 This embodiment provides a low-temperature resistant, high-modulus rubber asphalt, which differs from Embodiment 1 in that: The raw materials for preparing low-temperature resistant, high-modulus rubber asphalt include the following components: The following components were selected: 51 parts of Jingbo Petrochemical 70# road petroleum asphalt, 1 part of 2,2'-dibenzoylaminodiphenyl disulfide (80 mesh), 23 parts of waste tire rubber powder (60 mesh), 1 part of triallyl isocyanurate, 3 parts of fumed silica HL-380, 1.3 parts of KH550, 2 parts of EBS, 6 parts of SSBR, 5 parts of TC-24, 2 parts of KN-4006, 0.7 parts of nano zinc oxide, and 4 parts of coumarone resin.

[0068] Example 4 This embodiment provides a low-temperature resistant, high-modulus rubber asphalt, which differs from Embodiment 1 in that: The raw materials for preparing low-temperature resistant, high-modulus rubber asphalt include the following components: The composition of the following materials is as follows: 57 parts of Zhenhai Refining & Chemical 70# road petroleum asphalt, 1 part of 2,2'-dibenzoylaminodiphenyl disulfide (80 mesh), 16 parts of waste tire rubber powder (60 mesh), 2 parts of triallyl isocyanurate, 2 parts of fumed silica HL-380, 1.3 parts of KH550, 2 parts of EBS, 5 parts of SSBR, 6 parts of TC-24, 2 parts of KN-4006, 0.7 parts of nano zinc oxide, and 5 parts of coumarone resin.

[0069] Example 5 This embodiment provides a low-temperature resistant, high-modulus rubber asphalt, which differs from Embodiment 1 in that: The raw materials for preparing low-temperature resistant, high-modulus rubber asphalt include the following components: The composition includes: 65 parts of Zhenhai Refining & Chemical 70# road petroleum asphalt, 0.5 parts of 2,2'-dibenzoylaminodiphenyl disulfide (80 mesh), 10 parts of waste tire rubber powder (60 mesh), 3 parts of triallyl isocyanurate, 1 part of fumed silica HL-380, 0.1 part of KH550, 5 parts of EBS, 12 parts of SSBR, 1 part of TC-24, 1 part of KN-4006, 0.5 parts of nano zinc oxide, and 1 part of C9 petroleum resin.

[0070] Example 6 This embodiment provides a low-temperature resistant, high-modulus rubber asphalt, which differs from Embodiment 1 in that: The raw materials for preparing low-temperature resistant, high-modulus rubber asphalt include the following components: The composition of the following materials is as follows: 32.8 parts of Zhenhai Refining & Chemical 70# road petroleum asphalt, 4 parts of 2,2'-dibenzoylaminodiphenyl disulfide (80 mesh), 30 parts of waste tire rubber powder (60 mesh), 0.5 parts of triallyl isocyanurate, 3 parts of fumed silica HL-380, 2 parts of KH550, 1 part of EBS, 3 parts of SSBR, 10 parts of TC-24, 5 parts of KN-4006, 0.7 parts of nano zinc oxide, and 8 parts of C9 petroleum resin.

[0071] Comparative Example 1 This comparative example provides a high-modulus asphalt, the raw materials for which are prepared include the following components: 56 parts of Sinopec Jinshan Petrochemical 50# Grade A petroleum asphalt, 10 parts of Jianlong National Standard 10# solid asphalt, 20 parts of Sinopec Jinshan Petrochemical 70# Grade A petroleum asphalt, 6 parts of thermoplastic elastomer SBS Dushanzi Petrochemical 6302H, 5 parts of Mingzhi Industrial Aromatic Oil MZ-4, 2.97 parts of C9 petroleum resin, and 0.03 parts of sulfur.

[0072] The preparation process of high modulus asphalt is as follows: Heat 70# road petroleum asphalt and 50# asphalt to 170℃ until they reach a fluid state. After mixing, maintain the temperature and stir for 30 minutes. Add 10# solid asphalt and stir for 30 minutes. Add MZ-4 and petroleum resin and stir for 1 hour. Add SBS, raise the temperature to 180℃, and stir for 8 hours. Finally, maintain the temperature and add sulfur and stir for 30 minutes.

[0073] Comparative Example 2 This comparative example provides a rubber asphalt, which differs from Example 1 in that the raw materials for preparing the rubber asphalt do not contain silane coupling agents and silica, and the remainder is made up with base asphalt. Its preparation process does not include step 4.

[0074] Test case Test methods: The high-modulus asphalt of Examples 1-6 and Comparative Examples 1-2, and their prepared mixtures, were tested according to the methods in "JTG3410-2025 Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering". The test results are shown in Table 1.

[0075] Table 1

[0076] As shown in Table 1, the asphalt complex shear modulus, low-temperature flexibility, and dynamic viscosity at 60℃ of Examples 1-4 are superior to those of the comparative examples, indicating a significant improvement in high-temperature stability and low-temperature crack resistance. In terms of mixture application, key indicators such as dynamic modulus, maximum low-temperature flexural strain, and dynamic stability all meet the requirements for high-modulus asphalt concrete, demonstrating excellent overall road performance. In contrast, while Examples 5-6 still outperform the comparative examples overall, their performance is inferior to Examples 1-4, reflecting the need for optimal synergistic matching of formulation components within a reasonable range. Comparative Example 1, a traditional high-modulus asphalt formulation, exhibits poor low-temperature crack resistance and is prone to low-temperature cracking. Comparative Example 2, a rubberized asphalt formulation without secondary reinforcement using silica and silane coupling agents, has a significantly lower modulus than the example formulations, and its dynamic modulus does not meet the requirements for high-modulus asphalt concrete. This verifies the crucial role of the "chemical coupling + secondary reinforcement" structure in improving the modulus and durability of asphalt and asphalt mixtures. In summary, this invention effectively achieves synergistic optimization of high modulus and low-temperature resistance through a multi-level synergistic modification mechanism.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-temperature resistant, high-modulus rubber asphalt, characterized in that, The raw materials for its preparation include the following components: base asphalt, rubber powder, desulfurizer, free radical thermal initiation crosslinking agent, reinforcing agent, coupling agent, toughening agent, viscosity reducer and additives.

2. The low-temperature resistant, high-modulus rubber asphalt according to claim 1, characterized in that, The base asphalt is 70# road petroleum asphalt; Preferably, the rubber powder includes one or more of the following: waste tire rubber powder, waste rubber shoe rubber powder, industrial vulcanized rubber scraps powder, and waste conveyor belt rubber powder; Preferably, the particle size of the waste tire rubber powder includes at least one of 40 mesh, 60 mesh, and 80 mesh; Preferably, the desulfurizing agent comprises dibenzoylamino diphenyl disulfide; Preferably, the free radical thermally initiated crosslinking agent comprises triallyl isocyanurate; Preferably, the reinforcing agent comprises silica; Preferably, the coupling agent comprises a silane coupling agent; Preferably, the toughening agent comprises solution-polymerized styrene-butadiene rubber; Preferably, the viscosity reducer comprises at least one of vinyl bis-stearamide, ethylene bis-oleamide, and ethylene bis-lauramide.

3. The low-temperature resistant high-modulus rubber asphalt according to claim 1, characterized in that, The additives include one or more of the following: compatibilizers, softening desulfurization regenerators, crosslinking promoters, and thickening agents.

4. The low-temperature resistant high-modulus rubber asphalt according to claim 3, characterized in that, The compatibilizer includes aromatic oil; Preferably, the softening desulfurization regenerator comprises naphthenic oil; Preferably, the crosslinking agent comprises nano-zinc oxide; Preferably, the thickening agent comprises petroleum resin; Preferably, the petroleum resin includes at least one of C9 petroleum resin, coumarone resin, and terpene resin.

5. The low-temperature resistant high-modulus rubber asphalt according to claim 3, characterized in that, The raw materials for preparing the low-temperature resistant high-modulus rubber asphalt include, by weight, 50-65 parts base asphalt, 10-30 parts rubber powder, 0.5-4 parts desulfurizer, 0.5-3 parts free radical thermally initiated crosslinking agent, 1-3 parts reinforcing agent, 0.1-2 parts coupling agent, 1-5 parts viscosity reducer, 3-12 parts toughening agent, 1-10 parts compatibilizer, 1-5 parts softening desulfurization regenerator, 0.5-2 parts crosslinking promoter, and 1-8 parts viscosity enhancer.

6. The method for preparing low-temperature resistant high-modulus rubber asphalt according to any one of claims 1-5, characterized in that, Includes the following steps: (a) Rubber powder is added to the base asphalt in a fluid state to form rubber asphalt; (b) Add a desulfurizing agent to the rubber asphalt to perform desulfurization and decrosslinking; (c) Add a free radical-type thermally initiated crosslinking agent to perform crosslinking; (d) Add reinforcing agents and coupling agents to perform chemical coupling; (e) Add viscosity reducer, toughening agent and viscosity enhancer to obtain the low temperature resistant high modulus rubber asphalt.

7. The preparation method according to claim 6, characterized in that, In step (a), the base asphalt is heated and melted to a fluid state at a temperature of 160-180℃, and then rubber powder and compatibilizer are added and the temperature is raised to 170-190℃. Preferably, in step (b), the desulfurizing agent and the softening desulfurization regenerator are added at a temperature of 180-190°C and stirred for 30-60 minutes.

8. The preparation method according to claim 6, characterized in that, In step (c), a free radical thermal initiator and a crosslinking promoter are added at a temperature of 180-190°C.

9. The preparation method according to claim 6, characterized in that, In step (d), the reinforcing agent and coupling agent are added at a temperature of 180-190℃ and stirred for 40-60 minutes.

10. The preparation method according to claim 6, characterized in that, In step (e), a viscosity reducer, a toughening agent, and a viscosity-enhancing agent are added at a temperature of 170-180°C. Preferably, in step (e), the viscosity reducer and viscosity modifier are added first, followed by the toughening agent.

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