Modified high modulus agent for asphalt and preparation method thereof

Abstract

The invention discloses a modified high-modulus agent for asphalt and a preparation method of the modified high-modulus agent, and relates to the technical field of high-modulus agents. The invention relates to a modified high modulus agent for asphalt, which is prepared from the following components in parts by mass: 20-45 parts of petroleum resin, 5-20 parts of elastomer, 10-40 parts of modified rubber powder, 5-30 parts of inorganic rigid filler, 1-10 parts of nano inorganic enhancer, 5-25 parts of plasticizer, 1-10 parts of compatilizer, 0.5-1 part of anti-aging agent and 1-4 parts of gamma-glycidoxypropyltrimethoxysilane. Through the synergistic effect of silane coupling modification and the directional anchoring agent, the inert surface of the rubber powder is converted into an interface with reaction activity, the rubber powder, the resin, the elastomer and the inorganic filler can form a more stable multi-point bonding structure, and the interface stability of the whole system presents a remarkable enhancement trend.

Description

Technical Field

[0001] This invention relates to the field of high modulus agent technology, specifically to a modified high modulus agent for asphalt and its preparation method. Background Technology

[0002] In the field of road engineering, the performance of asphalt materials directly determines the load-bearing capacity, durability, and service life of the pavement. With the increase in traffic volume, the rise in heavy-duty vehicles, and the frequent occurrence of extreme weather, traditional asphalt pavements are prone to rutting, cracking, aging, and other defects, necessitating modification technologies to improve their overall performance. High-modulus agents, as key materials for asphalt modification, must simultaneously achieve multiple functions such as modulus enhancement, reinforcement, and anti-aging. Modified rubber powder, due to its wide availability and excellent elasticity, has become one of the core components of high-modulus agents.

[0003] However, the application of modified rubber powder in existing technologies faces significant bottlenecks: on the one hand, waste tire rubber powder has a strong surface inertness and poor interfacial compatibility with matrices such as asphalt and resin, easily leading to uneven dispersion and agglomeration. This results in stress concentration within the modified system, hindering the full utilization of the rubber powder's elasticity-enhancing effect and limiting the modulus improvement. On the other hand, rubber powder is susceptible to aging and degradation due to factors such as oxygen and ultraviolet radiation during long-term use, leading to elastic failure and interfacial peeling, which in turn exacerbates pavement damage. Traditional anti-aging agents are mostly free additives, making it difficult to target the rubber powder surface, resulting in low anti-aging efficiency and an inability to simultaneously address interfacial bonding issues.

[0004] Furthermore, the interfacial reinforcement and modulus-enhancing functions of existing high-modulus agents are often disconnected. The interfacial bonding between inorganic fillers and the organic matrix is ​​insufficient, and modulus enhancement relies heavily on the physical stacking of rigid fillers, which can easily lead to increased material brittleness and decreased crack resistance. Therefore, developing high-modulus agents that integrate "targeted" anti-aging modification of rubber, interfacial reinforcement, and modulus enhancement has become an urgent industry need. How to use precise modification technology to directionally anchor anti-aging components to the surface of rubber powder while simultaneously constructing a stable interfacial bonding system, thereby improving asphalt modulus while ensuring the long-term stability and toughness of the material, is a pressing technical challenge in the field of asphalt modification. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by providing a modified high-modulus agent for asphalt and its preparation method. This invention uses modified rubber powder as its core, integrating the functions of "targeted" anti-aging, strong interfacial bonding, and efficient modulus enhancement. The components are synergistically adapted, resulting in a modified high-modulus agent for asphalt that can significantly improve the modulus, durability, and crack resistance of asphalt.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a modified high modulus agent for asphalt, characterized in that it is made from the following components in parts by weight: 20-45 parts petroleum resin, 5-20 parts elastomer, 10-40 parts modified rubber powder, 5-30 parts inorganic rigid filler, 1-10 parts nano-inorganic reinforcing agent, 5-25 parts plasticizer, 1-10 parts compatibilizer, 0.5-1 part anti-aging agent, and 1-4 parts γ-glycidyl etheroxypropyltrimethoxysilane.

[0007] Furthermore, the method for preparing the modified rubber powder is as follows:

[0008] S1. After cleaning and drying the 20-80 mesh waste tire rubber powder, it is then dried with hot air at 50-90℃ for 0.5-2 hours to reduce the moisture content to below 0.5wt%, thus obtaining pretreated rubber powder.

[0009] S2. Prepare KH550 hydrolysate by mass ratio of KH550:water:ethanol = (1-5):(5-20):(10-40), adjust pH to 4.0-6.0, and stir hydrolyze at 25-50℃ for 0.5-2h to obtain silane hydrolysate;

[0010] S3. The pretreated rubber powder is added to the silane hydrolysate, and the solid content of the rubber powder is controlled to be 10-30 wt%. The mixture is mechanically stirred at 40-80℃ for 0.5-3 h to form a silane coupling layer on the surface of the rubber powder. Then it is filtered and dried at 60-110℃ for 1-4 h to obtain KH550 modified rubber powder.

[0011] S4. Mix the KH550 modified rubber powder with the directional anchoring agent at a mass ratio of 100:(1-8), and mix in a high shear mixer at 80-130℃ for 0.5-2h to allow the directional anchoring agent to be oriented and loaded onto the surface and near-surface of the rubber powder. After cooling, sieve to obtain the finished modified rubber powder.

[0012] Furthermore, in step S3, the ethanol to water mass ratio in the KH550 hydrolysate is (1.0-3.0):1, and before adding the rubber powder to the KH550 hydrolysate, the hydrolysate is pre-hydrolyzed and aged for 10-30 minutes.

[0013] Furthermore, the modified rubber powder is mechanically ground at a low temperature of 30-80℃ to control the particle size range of the finished product to 30-80 mesh.

[0014] Furthermore, the directional anchoring agent is S-(4-(ethylene oxide-2-ylmethoxy)butyl)3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl thioester.

[0015] Furthermore, the molecular structure of the directional anchoring agent is as follows: .

[0016] Furthermore, the petroleum resin is an aromatic C9 petroleum resin with a softening point of 110-140℃.

[0017] Furthermore, the elastomer is a mixture of styrene-butadiene-styrene block copolymer and styrene-butadiene rubber, with a mass ratio of 1:0.75-1.25.

[0018] Furthermore, the inorganic rigid filler is limestone powder and / or basalt powder;

[0019] Furthermore, the amount of inorganic rigid filler added should meet the following requirement: inorganic rigid filler / (petroleum resin + elastomer + modified rubber powder) = 0.15-0.60.

[0020] Furthermore, the nano-inorganic reinforcing agent is nano-silica and / or nano-alumina.

[0021] Furthermore, the plasticizer is one or more of dioctyl terephthalate, dioctyl adipate, and tributyl citrate.

[0022] Furthermore, the compatibilizer is maleic anhydride-grafted polyolefin.

[0023] Furthermore, the anti-aging agent is a compound of hindered phenolic antioxidant and hindered amine light stabilizer, with a mass ratio of 2-5:1.

[0024] The hindered phenolic antioxidant is one of antioxidant 1010 or antioxidant 1076;

[0025] The hindered amine light stabilizer is light stabilizer UV-292 or light stabilizer XH-622LD.

[0026] Furthermore, the aforementioned modified high-modulus agent for asphalt can be used as a non-metallic additive material, a new type of wall material, and a lightweight building material.

[0027] A method for preparing a high-modulus modifier for asphalt includes the following steps:

[0028] A1. Add the petroleum resin and plasticizer to a high-shear melting vessel equipped with a stirring and heating device, heat to 140-180℃, and keep at the temperature for 20-60 minutes with stirring at 300-800r / min to obtain the resin matrix molten phase;

[0029] A2. Add the elastomer and modified rubber powder to the molten phase of the resin matrix, control the system temperature at 170-200℃, stir at 800-2000 r / min, and shear for 30-90 min to obtain an elastic resin system.

[0030] A3. After the inorganic rigid filler, nano-inorganic reinforcing agent and γ-glycidyl etheroxypropyltrimethoxysilane are premixed evenly, they are added to the elastic resin system, and then the compatibilizer is added. The mixture is dispersed at 160-190℃ at a shear rate of 1000-3000 r / min for 20-60 min to obtain the elastic network resin system.

[0031] A4. Reduce the temperature of the elastic network resin system to 140-160℃, add the anti-aging agent, stir at 300-600r / min for 10-30min, then cool to room temperature using a cooling granulation device, and pelletize or granulate to obtain the modified high modulus agent for asphalt.

[0032] Furthermore, A1 and A2 are performed under a nitrogen atmosphere.

[0033] An application of a high modulus modifier for asphalt in the modification of road asphalt, wherein the high modulus modifier accounts for 3-6 wt% of the mass of the base asphalt as the addition amount.

[0034] This invention constructs a multi-scale composite system with modified rubber powder as the core, resin-elastomer as the matrix, and inorganic / nanofillers as the reinforcing skeleton. The components form a triple coupling mechanism of chemical bonding, physical interlocking, and interfacial synergy, thus systematically solving the technical problems of poor interfacial bonding, easy aging, uneven dispersion of rubber powder, and high brittleness of traditional high-modulus agents. Among these, the directional anchoring agent and modified rubber powder play a decisive role in interfacial regulation and anti-aging.

[0035] After surface modification of rubber powder using KH550, a directional anchoring agent is further introduced. This agent contains a hindered phenolic antioxidant structure and an anchoring structure that can directionally bind to active groups on the rubber surface, allowing the anti-aging unit to be precisely loaded onto the surface and near-surface region of the rubber powder. This "point-to-point" anchoring method significantly improves the utilization efficiency of the anti-aging agent, making it less prone to migration or dissipation under high-temperature shear and long-term service conditions, fundamentally inhibiting the thermo-oxidative degradation and chain segment breakage of the rubber powder. Simultaneously, the flexible segments of the directional anchoring agent can form good interfacial entanglement with the resin matrix and elastomer, strengthening the microscopic interfacial compatibility between the rubber powder and the organic phase. This results in a refined, stable, and uniform dispersion of the rubber powder in the matrix, effectively avoiding stress concentration and significantly improving the modulus and toughness of the modified system. Under the action of the silane coupling layer, the surface of the modified rubber powder changes from inert to reactive, not only enhancing its compatibility with petroleum resins and elastomers but also providing "multi-point anchoring" for the filler network structure, making the rubber powder the central supporting unit of the entire composite system. The directional anchoring agent introduced into the rubber powder further enhances the chemical bonding ability of the interface, enabling the rubber powder to efficiently transfer loads when bearing stress, thus providing a mechanism for the high modulus enhancement of this invention.

[0036] Based on this, petroleum resin and elastomer together constitute a continuous phase matrix. The resin provides a high-modulus basic framework, while the elastomer enhances the system's toughness, enabling the high-modulus agent in asphalt to improve overall structural stiffness without inducing brittleness. Inorganic rigid fillers and nano-inorganic reinforcing agents form a dense inorganic-organic network structure under the interfacial regulation of γ-glycidyl etheroxypropyltrimethoxysilane. Their microscale rigid filling and nanoscale reinforcing effects jointly construct a multi-scale load-bearing skeleton, significantly improving the system's resistance to deformation and high-temperature modulus. Plasticizers, through their internal reactive groups, chemically or through secondary bonding with the resin-rubber composite system, improve the system's fluidity and processing compatibility, and enhance flexibility and interfacial integration after curing. Compatibilizers further improve the compatibility between the organic phase and the rubber powder and inorganic phases, making the interfacial transition of the entire system smoother and more stable. Anti-aging agents, through synergy with directional anchoring agents, enable the entire system to form a two-level anti-aging mechanism of "overall and local," significantly improving the long-term service stability of the material.

[0037] In summary, this invention, with the synergistic interface between the directional anchoring agent and modified rubber powder as its core, along with a multi-scale synergistic network structure constructed from resin, elastomer, nano and micro fillers, compatibilizer, and plasticizer, significantly improves the dispersion stability, interfacial bonding strength, high modulus enhancement effect, and anti-aging performance of the high modulus agent in asphalt. This comprehensively solves the technical problems of insufficient modulus enhancement, interfacial weakening, and poor durability of existing high modulus agents.

[0038] Compared with the prior art, the beneficial effects of the present invention are:

[0039] 1. This invention transforms rubber powder from an inert surface into a reactive interface through the synergistic effect of silane coupling modification and directional anchoring agents. This interface can form a more stable multi-point bonding structure with resin, elastomer and inorganic filler, and the overall system interface stability shows a significant enhancement trend.

[0040] 2. This invention constructs a multi-level reinforcing network composed of a continuous resin-elastomer phase, modified rubber powder, and multi-scale inorganic fillers, which enables the material to maintain good flexibility and crack resistance while improving overall stiffness and load-bearing capacity, showing a trend of simultaneous development of modulus improvement and toughness improvement.

[0041] 3. Relying on the "fixed-point" anti-aging effect achieved by the directional anchoring agent on the surface of rubber powder, the anti-aging components are not easy to migrate or fail, which can effectively inhibit the thermo-oxidative degradation of rubber powder and interface, significantly improve the stability of the material under high temperature, heavy load and long-term service conditions, and show a significant trend of aging resistance strengthening. Attached Figure Description

[0042] Figure 1This is the infrared spectrum of the modified rubber powder described in this invention. Detailed Implementation

[0043] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely 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.

[0044] Preparation Example 1

[0045] Preparation of directional anchoring agent:

[0046] In a dry three-necked flask, under a continuous nitrogen flow, add 1.20 g of 4-mercapto-1-butanol and 1.23 g of triethylamine, followed by 15 mL of anhydrous dichloromethane, and stir to dissolve. Place the flask in an ice-water bath to cool to 0 °C. Dissolve 3.00 g of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl chloride in 15 mL of anhydrous dichloromethane, transfer to a constant-pressure dropping funnel, and slowly add the acyl chloride solution dropwise into the flask, controlling the dropping rate to keep the system temperature below 5 °C. Complete the addition within 25 min. After the addition is complete, maintain 0 °C and continue stirring for 30 min, then allow to naturally rise to room temperature and stir for 2 hours. After the reaction was completed, 20 mL of water was added to the reaction solution to quench the reaction. The mixture was then transferred to a separatory funnel, washed once with 20 mL of water, once with 20 mL of dilute hydrochloric acid (1 M), once with 20 mL of saturated sodium bicarbonate solution, and once with 20 mL of saturated saline solution to separate the organic phase. Anhydrous sodium sulfate was added and the mixture was dried for 30 minutes. The desiccant was removed by filtration, and the filtrate was evaporated under reduced pressure to obtain 2.80 g of S-(4-hydroxybutyl)3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanethioester.

[0047] In a dry three-necked flask, under a continuous nitrogen stream, 2.80 g of S-(4-hydroxybutyl)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propane thioester, 0.15 g of tetrabutylammonium bromide, and 12 mL of epichlorohydrin were added. The mixture was stirred at room temperature until the solid was completely dissolved. While stirring, 0.80 g of NaOH powder was added to the flask in four portions (10 minutes apart) to prevent localized overheating. The oil bath temperature was set at 50°C, and the temperature was not to exceed 60°C. The reaction was carried out for 4 hours. After the reaction was complete, the mixture was cooled to room temperature, and 30 mL of dichloromethane was added to dilute the reaction solution. The mixture was poured into a separatory funnel and gently washed with 30 mL of water. The organic phase was then washed once more with 30 mL of saturated brine. The organic phase was separated, dried over anhydrous sodium sulfate for 30 minutes, filtered, and the filtrate was subjected to rotary evaporation under reduced pressure (water bath temperature 65°C) to obtain the crude product. The crude product was purified by silica gel column chromatography. Using a mixed solution of petroleum ether and ethyl acetate as the eluent, impurities were washed with a solution of petroleum ether:ethyl acetate = 10:1, and the main product was collected with a solution of petroleum ether:ethyl acetate = 6:1. The product was then evaporated to dryness to give 2.02 g of S-(4-(ethylene oxide-2-ylmethoxy)butyl)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanethioester.

[0048] The mass spectrum of S-(4-(ethylene oxide-2-ylmethoxy)butyl)3-(3,5-di-tert-butyl-4-hydroxyphenyl)propane thioester is 423 [M+H]. + .

[0049] Preparation Example 2

[0050] Preparation of modified rubber powder:

[0051] S1. Take 50g of waste tire rubber powder with a particle size of 40 mesh, place it in 500ml of deionized water and stir and wash it thoroughly for 10min. After filtration, pre-dry it in a 60℃ hot air circulating oven for 30min. Then spread the rubber powder on a stainless steel tray and continue to dry it in hot air at 80℃ for 60min until the moisture content of the rubber powder is reduced to below 0.5wt%, and obtain pretreated rubber powder for later use.

[0052] S2. In a 250 mL three-necked flask equipped with a mechanical stirrer, add 36 g of deionized water and 72 g of anhydrous ethanol, controlling the mass ratio of ethanol to water to be 2:1. Stir at room temperature for 5 min to mix evenly. Then add 9 g of γ-aminopropyltriethoxysilane (KH550), continue stirring for 10 min, adjust the pH of the system to 4.5 with glacial acetic acid, stir at 40 °C for pre-hydrolysis and aging for 20 min, and continue hydrolysis for 40 min to obtain a clear and transparent KH550 hydrolysate.

[0053] In this step, the mass ratio of KH550:water:ethanol is 3:12:24, which meets the requirement of KH550:water:ethanol = (1-5):(5-20):(10-40), and the total mass of the system is 117g.

[0054] S3. In a 500mL reactor equipped with a mechanical stirrer and a constant-temperature water bath, add 117g of the KH550 hydrolysate obtained in S2. Add 50g of the pretreated rubber powder obtained in S1 slowly in batches to the hydrolysate under stirring conditions, controlling the addition time to 10min to avoid local agglomeration. Adjust the stirring speed to 400r / min and mechanically stir at 60℃ for 90min to form a uniform coupling layer of KH550 on the surface of the rubber powder. The solid content of the rubber powder in the system is approximately 30wt%. After stirring, separate the mixed slurry by vacuum filtration. The filter cake was rapidly washed twice with a 50wt% ethanol aqueous solution to remove unreacted small molecule impurities. The filter cake was then transferred to a stainless steel tray and dried in a 90℃ hot air circulating oven for 120 min to reduce the residual moisture content to below 0.5wt%, yielding crude KH550 modified rubber powder. Subsequently, the dried KH550 modified rubber powder was fed into a mechanical mill with a cooling jacket and finely ground at a low temperature below 40℃. The powder was then classified through a 40-mesh sieve, and the product with a particle size of approximately 40 mesh was collected to obtain KH550 modified rubber powder with uniform particle size.

[0055] S4. Take 50g of KH550 modified rubber powder obtained in step (3) and add it to an internally heated stainless steel mixing vessel equipped with a high-shear stirring head. Under nitrogen protection, heat the mixture to 100℃ and pre-stir at 500r / min for 5min. Then add 2.5g of the directional anchoring agent S-(4-(ethylene oxide-2-ylmethoxy)butyl)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propane thioester obtained in Preparation Example 1, so that the mass ratio of the directional anchoring agent to the KH550 modified rubber powder is 100:5. Adjust the stirring speed to 1200r / min and mix at 100℃ under high shear for 60min to directionally load the directional anchoring agent onto the surface and near-surface area of ​​the rubber powder.

[0056] The infrared spectrum of the modified rubber powder is as follows: Figure 1 As shown, in the infrared spectrum of the modified rubber powder of the present invention, at approximately 3400 cm⁻¹... -1 A relatively wide absorption band appears at 2920 cm⁻¹, corresponding to the stretching vibrations of the phenolic hydroxyl group in the anchoring agent and the -NH / -OH groups in KH550; -1 and 2850cm -1 A strong absorption peak appears at approximately 1730-1700 cm⁻¹, which is due to the -CH₂- / -CH₃ stretching vibration of the rubber backbone and tert-butyl groups; -1The presence of a distinct carbonyl absorption peak within the range indicates the presence of a thioester / ester group structure in the system; 1600-1500 cm⁻¹ -1 In this region, C=C skeletal vibrations of the aromatic ring and -NH bending vibrations can be observed; 1100-1000 cm⁻¹ -1 The region exhibits a strong and broad absorption band, corresponding to the stretching vibrations of Si-O-Si, Si-OC, and polyether chain COC; at 970 and 910 cm⁻¹... -1 There is out-of-plane bending absorption of the butadiene CH structure in the vicinity, at 800-600 cm⁻¹. -1 The region exhibits characteristic absorptions such as Si-C, CS, and outward bending of aromatic rings. These characteristic peaks collectively indicate that KH550 has been successfully grafted onto the surface of waste tire rubber powder, and that the directional anchoring agent containing hindered phenol / thioester structures has been effectively loaded.

[0057] Comparative Preparation Example 1

[0058] The modified rubber powder was prepared by referring to the preparation method of Preparation Example 2, except that the amount of KH550 was replaced with 18g (i.e., the mass ratio of KH550:water:ethanol was 6:12:24), and the rest remained the same as in Preparation Example 2.

[0059] Comparative Preparation Example 2

[0060] The modified rubber powder was prepared by referring to the preparation method of Preparation Example 2, except that KH550 was replaced with KH560, and the rest remained the same as in Preparation Example 2.

[0061] Comparative preparation example 3

[0062] The modified rubber powder was prepared by referring to the preparation method of Preparation Example 2, except that the directional anchoring agent was replaced with Comparative Compound 1, and the rest remained the same as in Preparation Example 2.

[0063] Comparative compound 1: .

[0064] Comparative preparation example 4

[0065] The modified rubber powder was prepared by referring to the preparation method of Preparation Example 2, except that the directional anchoring agent was replaced with antioxidant 1010, and the rest remained the same as in Preparation Example 2.

[0066] Comparative preparation example 5

[0067] The modified rubber powder was prepared according to the preparation method of Preparation Example 2, except that the directional anchoring agent was not added, and the rest remained the same as in Preparation Example 2.

[0068] Example 1

[0069] Preparation of a high-modulus modifier for asphalt:

[0070] 1. Raw material weight formula:

[0071] Petroleum resin: Aromatic C9 petroleum resin (softening point 125℃): 35 parts;

[0072] Elastomer (styrene-butadiene-styrene block copolymer: styrene-butadiene rubber = 1:1 by mass): 12 parts;

[0073] Modified rubber powder (prepared in Preparation Example 2): 30 parts;

[0074] Inorganic rigid filler (limestone powder): 15 parts;

[0075] Nano-inorganic reinforcing agent (nano-silica, particle size 15nm): 5 parts;

[0076] Plasticizer (dioctyl adipate): 15 parts;

[0077] Compatibilizer (maleic anhydride grafted polyolefin, MAH content 1.0wt%): 5 parts;

[0078] Anti-aging agent (antioxidant 1010: light stabilizer UV-292 = 3:1 mass ratio): 0.8 parts;

[0079] γ-glycidyl etheroxypropyltrimethoxysilane: 2 parts.

[0080] 2. Preparation method:

[0081] A1. Add aromatic C9 petroleum resin and plasticizer into a melting kettle equipped with a high shear device, turn on nitrogen protection, heat the system to 160℃, control the stirring speed to 600r / min, and melt at a constant temperature for 40min to form a uniform resin matrix molten phase.

[0082] A2. In the resin matrix molten phase obtained in A1, add elastomer and modified rubber powder, heat to 185℃, adjust the shear rate to 1500 r / min, and shear and disperse under this condition for 60 min to obtain a uniform elastic resin system.

[0083] A3. Limestone powder, nano-silica and γ-glycidyl etheroxypropyltrimethoxysilane were added to a premix container in sequence and premixed at 1500 r / min for 10 min. Then the premixed system was added to the elastic resin system obtained in step A2. The system temperature was controlled at 175℃. Then 5 parts of compatibilizer were added, the shear speed was increased to 2000 r / min, and the system was continuously dispersed for 40 min to obtain the elastic network resin system.

[0084] A4. Reduce the temperature of the elastic network resin system to 150°C, add the anti-aging agent, stir at 400 r / min for 20 min to make it uniformly dispersed, then quickly cool the system to room temperature through a cooling granulation device, and cut it into uniform particles with a particle size of 2-3 mm by a pelletizing mechanism to obtain a modified high modulus agent for asphalt of the present invention.

[0085] Example 2

[0086] The preparation of a modified high modulus agent for asphalt is carried out by referring to the preparation method of Example 1, except that the mass fraction of inorganic rigid filler is replaced with 11.55 parts (i.e., inorganic rigid filler / (petroleum resin + elastomer + modified rubber powder) = 0.15), and the rest is the same as in Example 1.

[0087] Example 3

[0088] The preparation of a modified high modulus agent for asphalt is carried out by referring to the preparation method of Example 1, except that the mass fraction of inorganic rigid filler is replaced with 30.8 parts (i.e., inorganic rigid filler / (petroleum resin + elastomer + modified rubber powder) = 0.40), and the rest is the same as in Example 1.

[0089] Example 4

[0090] The preparation of a high modulus modifier for asphalt is carried out by referring to the preparation method of Example 1, except that the elastomer component is replaced with 5.33 parts of styrene-butadiene-styrene block copolymer and 6.67 parts of styrene-butadiene rubber, while the rest remains the same as in Example 1.

[0091] Comparative Examples 1-5

[0092] The preparation of a modified high modulus agent for asphalt is carried out by referring to the preparation method of Example 1, except that the modified rubber powder is replaced in turn with the modified rubber powder prepared in Comparative Preparation Examples 1-5, and the rest is the same as in Example 1.

[0093] Comparative Example 6

[0094] The preparation of a modified high modulus agent for asphalt is carried out by referring to the preparation method of Example 1, except that the mass fraction of inorganic rigid filler is replaced with 10.01 parts, that is, inorganic rigid filler / (petroleum resin + elastomer + modified rubber powder) = 0.13, and the rest is the same as in Example 1.

[0095] Comparative Example 7

[0096] The preparation of a modified high modulus agent for asphalt is carried out by referring to the preparation method of Example 1, except that the mass fraction of inorganic rigid filler is replaced with 50.05 parts, that is, inorganic rigid filler / (petroleum resin + elastomer + modified rubber powder) = 0.65, and the rest is the same as in Example 1.

[0097] Performance testing:

[0098] Modified asphalt was prepared by adding a high-modulus modifier at a dosage of 5 wt% of the base asphalt. The base asphalt used was 70# road petroleum asphalt (compliant with JTGF40-2004 standard). The base asphalt was heated to 170℃ to melt, and the metered high-modulus modifier was added. The mixture was then dispersed under high-speed shear at 180℃ and 1500 r / min for 40 min, followed by curing in a 160℃ oven for 60 min to obtain a homogeneous and stable modified asphalt sample.

[0099] Asphalt mixtures were prepared using the modified asphalt samples described above.

[0100] Aggregates and gradation: Basalt coarse aggregate, limestone fine aggregate and mineral powder are selected. The gradation type is AC-13C dense gradation asphalt mixture (or AC-20, etc., depending on the actual experimental conditions). The gradation curve meets the requirements of the "Technical Specification for Construction of Highway Asphalt Pavement" (JTGF40-2004).

[0101] Optimal oil-stone ratio: determined according to the Marshall experimental design method, the optimal oil-stone ratio in this embodiment and the comparative embodiment is uniformly controlled at 4.8%.

[0102] Specimen molding and testing: Tests were conducted according to the relevant test methods in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2011).

[0103] Dynamic modulus: Following method T0738, a cylindrical specimen with a diameter of 100 mm × 150 mm was formed using a rotary compactor, and the dynamic modulus was tested at a temperature of 15℃ and a loading frequency of 10 Hz.

[0104] High-temperature performance (dynamic stability): According to method T0719, 300mm×300mm×50mm rutting plate specimens were formed by wheel rolling and rutting test was carried out at 60℃ and 0.7MPa wheel pressure to determine dynamic stability (cycles / mm).

[0105] Low-temperature performance (beam bending): The rutted plate was cut into small beam specimens of 250mm×30mm×35mm according to method T0715, and a low-temperature bending test was carried out at -10℃ to determine the failure strain (με).

[0106] High-temperature performance retention rate: After the molded rutting plate specimens are placed in an 80℃ ventilated oven for 3600h of heat aging, they are taken out and cooled to room temperature. The rutting test is then repeated to determine the dynamic stability, and the ratio of the dynamic stability after aging to the dynamic stability before aging (retention rate) is calculated.

[0107] Table 1 Dynamic modulus at 15℃, 10Hz, MPa High-temperature performance dynamic stability per cycle / mm Low-temperature performance small beam bending failure strain με High-temperature performance retention rate % Example 1 17250 14800 3850 96.5 Example 2 15400 12500 4150 95.8 Example 3 18600 16200 3350 96.2 Example 4 17100 14500 3900 96.0 Comparative Example 1 14800 10200 3250 88.5 Comparative Example 2 14200 9600 3050 86.4 Comparative Example 3 15300 13800 3650 75.5 Comparative Example 4 15100 14100 3600 70.2 Comparative Example 5 14100 9800 3050 58.5 Comparative Example 6 10500 5800 4800 93.6 Comparative Example 7 20800 18500 1950 94.5

[0108] Example 1 uses rubber powder that has been surface-modified with KH550 and further loaded with a directional anchoring agent. In the petroleum resin-elastomer continuous phase, it forms a dense rigid-flexible synergistic framework with limestone micropowder and nano-SiO2 through silane bridging bonds and reactive groups such as epoxy / hydroxyl groups on the directional anchoring agent. Therefore, the dynamic modulus can reach 17250 MPa at 15℃ and 10Hz, and the dynamic stability in a rutting test at 60℃ is 14800 cycles / mm. Simultaneously, because the elastomer and rubber phase still occupy a certain volume fraction, the low-temperature strain remains around 3850 με without excessive embrittlement. When the proportion of inorganic rigid filler is reduced to 0.15... In Example 2, the contact and bridging between rigid particles weaken, and the number of skeleton "beams and columns" decreases. Macroscopically, this results in a decrease in modulus and dynamic stability to 15400 MPa and 12500 cycles / mm, respectively. However, the proportion of flexible phase increases, and stress is more easily diffused and dissipated in the rubber / elastomer phase, thus increasing the low-temperature failure strain to the highest level of 4150 με in the table. Conversely, in Example 3, the filler ratio is increased to 0.40, and a more continuous mineral powder-resin-rubber three-phase network is formed between rigid particles through silane and directional anchoring agents. Under load, the stress is concentrated on the rigid skeleton, thus further improving the dynamic modulus and dynamic stability. The modulus increased to 18600 MPa and 16200 cycles / mm, but the stress concentration near the interface intensified and the flexible phase was "compressed," resulting in a decrease in low-temperature strain to 3350 με, exhibiting a typical stiffening effect of "high modulus-high rutting resistance but slightly reduced crack resistance." In Example 4, the SBS / SBR ratio was adjusted while keeping the filler ratio unchanged, resulting in a slightly higher proportion of linear SBR and more complete movement of the soft segment chain. While maintaining the modulus of 17100 MPa and rutting performance of 14500 cycles / mm, the low-temperature strain was slightly increased from 3850 με in Example 1 to 3900 με, indicating that the low-temperature strain was slightly increased from 3850 με in Example 1 to 3900 με by optimizing the elastomer microstructure. The structure can improve low-temperature toughness without sacrificing high-temperature skeleton stiffness. Although Comparative Examples 1 and 2 also used silane-modified rubber powder, the excessive amount of KH550 or the replacement with KH560 led to abnormal hydrolysis and condensation behavior, uneven distribution of inorganic and organic phases on the surface of the rubber powder, and reduced interfacial chemical bonding and stress transfer efficiency. As a result, the modulus and dynamic stability were only 14800 / 10200 and 14200 / 9600, respectively, and the low-temperature strain was slightly lower (3250 and 3050 με). At the same time, since the directional anchoring antioxidant system still partially existed, the high-temperature performance retention rate after aging could still be maintained at about 88.5% and 86%, respectively.4%; In Comparative Examples 3 and 4, the directional anchoring agent was replaced with Comparative Compound 1 or Free Antioxidant 1010. Initially, the three-phase geometry of the resin-filler-rubber remained relatively intact, so the modulus and dynamic stability were not significantly worse than in Examples 1-2 (approximately 15300 / 13800 and 15100 / 14100). However, the antioxidant component was not anchored at the rubber-inorganic interface and preferentially migrated or was consumed from the interface under thermo-oxygen conditions. Oxidative hardening and microcrack propagation occurred on the rubber surface. After interfacial peeling, the skeletal load-bearing channels were destroyed, resulting in a sharp drop in the high-temperature retention rate of dynamic stability to 75.5%. The 70.2% figure fully demonstrates the importance of "antioxidant directional anchoring at the interface" for long-term high-temperature stability. In Comparative Example 5, when the directional anchoring agent was completely removed, the rubber powder relied solely on physical interlocking and a small amount of chemical bonding brought about by KH550 modification. The interfacial bonding strength and anti-aging protection were the weakest, as evidenced by a significant decrease in initial modulus and rutting performance (14100MPa, 9800 cycles / mm). Furthermore, only 58.5% of the rutting performance was retained after aging, and the low-temperature strain was only 3050με. This indicates that the weak interfacial layer and oxidative embrittlement severely damaged the rubber powder, both in the short and long term. The continuous skeleton was used in Comparative Examples 6 and 7, while maintaining the directional anchoring agent system, with the proportion of inorganic rigid filler reduced to 0.13 and increased to 0.65 respectively. The former showed insufficient "bridging" between skeleton particles and incomplete development of the rigid load-bearing network, resulting in the lowest dynamic modulus and dynamic stability at 10500 MPa and 5800 cycles / mm, respectively. However, the high proportion of the flexible phase allowed for low-temperature strain up to 4800 με without cracking. The latter formed an excessively dense rigid particle skeleton, with the load almost entirely transferred along the rigid phase, resulting in a significant increase in initial modulus and rutting performance to 20800 MPa. Despite a strain of 18,500 cycles / mm, the flexible buffer phase was severely compressed, and the interface constraint was too strong, leading to rapid brittle failure at -10℃, with the low-temperature strain dropping to 1950 με. However, due to the presence of a directional anchoring antioxidant structure at the interface, the high-temperature performance retention rate after aging could still be maintained at around 94.5%. In summary, all the data in Table 1 clearly demonstrate, from a microscopic perspective, the mechanism by which a multi-scale high-modulus network is synergistically constructed through "directional anchoring interface + suitable rigid filler skeleton density + elastomer microstructure adjustment," achieving an adjustable balance between high-temperature rutting resistance, low-temperature crack resistance, and long-term durability.

[0109] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A modified high modulus agent for bitumen, characterized by, The composition is prepared from the following components by mass fraction: petroleum resin 20-45 parts, elastomer 5-20 parts, modified rubber powder 10-40 parts, inorganic rigid filler 5-30 parts, nano inorganic reinforcing agent 1-10 parts, plasticizer 5-25 parts, compatibilizer 1-10 parts, anti-aging agent 0.5-1 part, gamma-glycidyl ether oxypropyl trimethoxysilane 1-4 parts; The preparation method of the modified rubber powder is: S1. After washing and drying 20-80 mesh waste tire rubber powder, hot air drying at 50-90℃ for 0.5-2h, the water content is reduced to below 0.5wt%, and the pretreated rubber powder is obtained; S2. Prepare KH550 hydrolysate according to the mass ratio of KH550: water: ethanol = (1-5): (5-20): (10-40), adjust the pH to 4.0-6.0, and hydrolyze at 25-50℃ for 0.5-2h with stirring to obtain silane hydrolysate; S3. Add the pretreated rubber powder to the silane hydrolysate, control the solid content of the rubber powder to be 10-30wt%, mechanically stir at 40-80℃ for 0.5-3h, and form a silane coupling layer on the surface of the rubber powder; then filter and dry at 60-110℃ for 1-4h to obtain KH550 modified rubber powder; S4. Mix the KH550 modified rubber powder with the directional anchoring agent according to the mass ratio of 100:(1-8), mix in a high shear mixer at 80-130℃ for 0.5-2h, so that the directional anchoring agent is directionally loaded on the surface and near-surface layer of the rubber powder, and sieve after cooling to obtain the finished modified rubber powder; The directional anchoring agent is S-(4-(oxirane-2-ylmethoxy)butyl) 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanethioate.

2. The modified high modulus agent for bitumen as claimed in claim 1, wherein, The petroleum resin is aromatic C9 petroleum resin, and the softening point is 110-140℃.

3. The modified high modulus agent for bitumen as claimed in claim 1, wherein the high modulus agent is a mixture of the components (a) and (b). The elastomer is a mixture of styrene-butadiene-styrene block copolymer and styrene-butadiene rubber, and the mass fraction ratio of the two is 1:0.75-1.

25.

4. The modified high modulus agent for bitumen as claimed in claim 1, wherein the high modulus agent is a mixture of the components (a) and (b). The inorganic rigid filler is limestone powder and / or basalt powder; And the addition amount of inorganic rigid filler should meet: inorganic rigid filler / (petroleum resin+elastomer+modified rubber powder)=0.15-0.

60.

5. The modified high modulus agent for bitumen as claimed in claim 1, wherein the high modulus agent is a mixture of 1,3-phenylenediamine and 1,4-phenylenediamine. The nano inorganic reinforcing agent is nano silicon dioxide and / or nano aluminum oxide.

6. The modified high modulus agent for bitumen as claimed in claim 1, wherein the high modulus agent is a mixture of the components (a) and (b). The plasticizer is one or more of dioctyl terephthalate, dioctyl adipate, and tributyl citrate.

7. The modifier for high modulus of asphalt as set forth in claim 1, wherein the modifier is a mixture of the polybutene and the polyisoprene. The compatibilizer is maleic anhydride grafted polyolefin; The anti-aging agent is compounded from a hindered phenolic antioxidant and a hindered amine light stabilizer, and the mass fraction ratio of the two is 2-5:1; The hindered phenolic antioxidant is one of antioxidant 1010 or antioxidant 1076; The hindered amine light stabilizer is light stabilizer UV-292 or light stabilizer XH-622LD.

8. A method for preparing a modified high modulus agent for bitumen as claimed in any one of claims 1 to 7, characterized in that, The method comprises the following steps: A1. Add the petroleum resin and plasticizer to a high shear melting kettle with stirring and heating device, heat to 140-180℃, and keep at 300-800r / min stirring for 20-60min to obtain a resin matrix melt phase; A2. In the resin matrix melt phase, the elastomer and modified rubber powder are added, the system temperature is controlled at 170-200℃, the stirring speed is 800-2000r / min, and the shearing time is 30-90min, to obtain an elastic resin system; A3. The inorganic rigid filler and nano inorganic reinforcing agent are uniformly premixed with the γ-glycidyl ether oxypropyl trimethoxysilane, which is then added to the elastic resin system, followed by the addition of the compatilizer, and dispersed at 160-190℃ and a shearing speed of 1000-3000r / min for 20-60min, to obtain an elastic network resin system; A4. The temperature of the elastic network resin system is reduced to 140-160℃, the anti-aging agent is added, and stirred at 300-600r / min for 10-30min, followed by cooling to room temperature through a cooling granulation device, and cutting or granulating, to obtain the modified high modulus agent for asphalt.

9. A method for preparing a high-modulus modifier for asphalt according to claim 8, characterized in that, The A1 and A2 are performed under a nitrogen atmosphere.

10. The use of the modified high modulus agent for asphalt according to any one of claims 1-7 in the modification of road asphalt, with the addition amount of the modified high modulus agent being 3-6wt% of the base asphalt.

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