A modified filler, sma-13 asphalt mixture and a method for preparing the same

Abstract

The application discloses a modified filler, SMA-13 asphalt mixture and a preparation method thereof, relates to the technical field of asphalt, and the SMA-13 asphalt mixture is prepared from the following components: 4-8 parts of SMA-13 asphalt, 4-8 parts of modified filler, 50-80 parts of coarse aggregate and 20-50 parts of fine aggregate; the modified filler is prepared from the following components: 10 parts of phosphogypsum, 5-8 parts of quicklime, 5-60 parts of limestone and 10-30 parts of modified basalt fiber; the asphalt mixture prepared by the application has excellent high-temperature stability, low-temperature crack resistance, water damage resistance and fatigue durability, the service life of a road is prolonged, the maintenance cost is reduced, and a safe, economical, environment-friendly and efficient new material system is provided for the road construction industry.

Description

Technical Field

[0001] This invention relates to the field of asphalt technology, specifically to a modified filler, SMA-13 ​​asphalt mixture, and its preparation method. Background Technology

[0002] Asphalt mixtures are composite materials made by mixing asphalt and aggregates in a certain proportion. They are the main structural materials for highways, airports, urban roads, and plaza pavements. Based on gradation characteristics and functional requirements, asphalt mixtures can be classified into various types, including dense-graded, open-graded, asphalt-mash, asphalt-penetrating-mash, and porous asphalt mixtures. Among them, SMA (Stone Matrix Asphalt) mixture is a dense-skeleton asphalt mixture, composed of a coarse aggregate skeleton, asphalt mastic (a mixture of asphalt and filler), and fiber stabilizers. It is characterized by "more coarse aggregate and less fine aggregate, with discontinuous gradation." SMA mixtures are widely used in high-grade highways and heavy-duty traffic pavements due to their excellent high-temperature stability, rutting resistance, skid resistance, wear resistance, and aging resistance.

[0003] Phosphogypsum is a major solid waste generated during the wet-process phosphoric acid production process, and its main component is calcium sulfate dihydrate. Resource utilization of phosphogypsum is an effective way to solve its environmental problems. Currently, its main applications include cement retarder, building gypsum, ammonium sulfate production, and roadbed filler. However, due to impurities such as residual free acid, soluble phosphorus, and fluorine in phosphogypsum, its direct application is severely limited, especially when used as a filler in road engineering, where its acidic characteristics affect the water stability and durability of asphalt mixtures.

[0004] Publication No. CN108147771A discloses an asphalt concrete comprising the following raw materials in parts by weight: 47 parts base asphalt, 3 parts stabilizer, 2 parts modifier, 7 parts UV-blocking particles, and 39 parts concrete; wherein the stabilizer is sulfur, the modifier is YH791H linear SBS, and the concrete is a mixture of sodium sulfite powder, reinforcing fiber, fly ash, iron powder, phosphogypsum, and aggregate.

[0005] However, with the continuous increase in traffic load and the increasing complexity of climatic conditions, existing asphalt mixture technologies face numerous challenges: First, rutting deformation of pavements under high-temperature conditions remains a prominent issue, especially in areas with heavy traffic and extreme high-temperature climates; second, asphalt mixtures become more brittle at low temperatures, making them prone to temperature stress cracking and fatigue cracking; third, water damage, as a major factor affecting the durability of asphalt pavements, leads to asphalt-aggregate interface delamination and reduced strength; fourth, asphalt mixtures are affected by multiple factors during service, including ultraviolet radiation, oxygen oxidation, and moisture erosion, accelerating aging and causing performance degradation; fifth, existing modification technologies generally suffer from high costs, complex processes, and poor environmental friendliness, and it is difficult to achieve synergistic improvements in multiple properties. Furthermore, while the resource utilization of industrial by-products is beneficial for resource conservation and environmental protection, solving the stability and compatibility issues during application remains a technical challenge.

[0006] Therefore, developing a multifunctional synergistic modified filler system to solve the comprehensive performance problem of asphalt mixtures in complex environments, while realizing the resource utilization of industrial by-products, has important theoretical research value and engineering application prospects. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a modified filler, SMA-13 ​​asphalt mixture, and its preparation method. The SMA-13 ​​asphalt mixture achieves a significant improvement in the comprehensive performance of pavement materials through a multi-functional synergistic enhancement mechanism. It can effectively solve the technical problem of poor service performance of traditional asphalt mixtures under extreme climate and heavy traffic conditions, and also realizes the resource utilization of industrial by-products, thus having significant economic and environmental benefits.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A modified filler, by weight, is made of the following components: 10 parts phosphogypsum, 5-8 parts quicklime, 5-60 parts limestone, and 10-30 parts modified basalt fiber.

[0010] The phosphogypsum has a particle size of 150-500 mesh and a pH value of 3.5-4.1; the quicklime has a particle size of 150-500 mesh and the limestone has a particle size ≤0.6mm.

[0011] Preferably, the method for preparing the modified basalt fiber includes the following steps:

[0012] (1) The basalt fiber was washed and then immersed in an ethanol aqueous solution. 3-piperazinylpropylmethyldimethoxysilane was added to adjust the pH of the system. The reaction was stirred and the product was filtered, washed and dried to obtain the pretreated fiber.

[0013] Surface treatment of silane coupling agents: 3-piperazinylpropylmethyldimethoxysilane first undergoes hydrolysis in an acidic aqueous ethanol solution, where the methoxy group (–OCH3) reacts with water molecules to generate silanol groups (–Si–OH) and methanol. Subsequently, the hydrolyzed silane undergoes a condensation reaction with the siloxy groups (Si–OH) on the surface of basalt fibers, forming a stable silicon-oxygen bond (Si–O–Si) structure. Simultaneously, condensation cross-linking may also occur between adjacent silanol groups, forming a network structure. This process firmly grafts the piperazine groups (containing secondary amine groups) onto the fiber surface, providing active sites for subsequent reactions. The entire process is affected by pH; an acidic environment favors the hydrolysis of silane, while increasing the temperature accelerates the condensation reaction rate.

[0014] Preferably, in step (1), the basalt fiber is ultrasonically cleaned with acetone and deionized water for 10-20 min in sequence; the pH of the system is adjusted to 4-5 with glacial acetic acid; and the stirring reaction is carried out at 60-75℃ for 3-6 h.

[0015] Preferably, in step (1), the ratio of basalt fiber, ethanol aqueous solution, and 3-piperazinylpropylmethyldimethoxysilane is 10g:150~200mL:4~8g; the volume ratio of ethanol and deionized water in the ethanol aqueous solution is 80~90:10~20.

[0016] (2) Disperse the pretreated fiber in xylene, then add diethyl 2-allyl phosphite, add BPO dropwise under a nitrogen atmosphere, reflux the reaction, filter, wash and dry the product to obtain intermediate fiber;

[0017] Radical-Initiated Grafting Reaction: Using BPO as a radical initiator, under heating conditions, BPO first decomposes to generate benzoyloxy radicals, which then decarboxylate to form phenyl radicals. These highly reactive radicals extract hydrogen atoms from the secondary amine group (–NH–) on the piperazine ring, generating nitrogen radicals. These nitrogen radicals initiate nucleophilic addition attacks on the C=C double bond in the 2-allyl phosphite diethyl ester molecule. Subsequently, the carbon radical terminates the reaction chain through hydrogen extraction or combination with other radicals. The entire reaction must be carried out under a nitrogen atmosphere to prevent oxygen quenching of the radicals and reducing grafting efficiency.

[0018] Preferably, in step (2), the ratio of the amount of pretreated fiber, xylene, diethyl 2-allyl phosphite and BPO is 10g: 100~150mL: 2~3.5g: 0.02~0.05g.

[0019] Preferably, in step (2), the reflux reaction conditions are reflux reaction at 65~80℃ for 4~7h; the product is washed with acetone and THF 2~3 times in sequence.

[0020] (3) Disperse the intermediate fiber in DMF / THF solvent, then add epoxy SBS and triethylamine, stir evenly, reflux reaction, filter, wash and dry the product to obtain modified basalt fiber.

[0021] Ring-opening addition of epoxy groups to secondary amines: Triethylamine, acting as a basic catalyst, first activates the residual secondary amine groups on the fiber surface, enhancing their nucleophilicity. The activated secondary amine anions then nucleophilically attack the epoxy groups in the epoxy-based SBS, leading to ring-opening of the epoxy ring. Since multiple epoxy groups exist on the SBS molecular chain, one SBS molecule may react with multiple secondary amine groups on the fiber surface, forming a network cross-linked structure. Simultaneously, the hydroxyl groups generated in the reaction may undergo secondary reactions with the epoxy groups, further increasing the cross-linking density.

[0022] Preferably, in step (3), the ratio of intermediate fiber, DMF / THF solvent, epoxy group SBS and triethylamine is 10g:100~120mL:3~7g:0.05~0.2g; the volume ratio of DMF and THF in the DMF / THF solvent is 7~8:2~3.

[0023] Preferably, in step (3), the reflux reaction conditions are 200~400r / min and 75~90℃ for 7~10h; the product is washed with THF and ethanol 2~3 times in sequence.

[0024] Preferably, in step (3), the preparation method of epoxy group SBS includes the following steps: take styrene and cyclohexane, stir and heat to 55~65℃, add n-butyllithium, stir for 30~60min, add butadiene, react for 30~60min, add styrene, react for 20~40min, add propylene oxide, react for 10~20min, add epichlorohydrin, react for 10~20min, polymerize and dry to obtain epoxy group SBS.

[0025] The present invention also claims a method for preparing a modified filler, comprising the following steps: mixing phosphogypsum, quicklime, limestone, and modified basalt fiber at 50-80 r / min for 60-180 s to obtain the modified filler.

[0026] This invention also claims protection for an SMA-13 ​​asphalt mixture, which, by weight, is made of the following components: 4-8 parts SMA-13 ​​asphalt, 4-8 parts modified filler, 50-80 parts coarse aggregate, and 20-50 parts fine aggregate.

[0027] This invention also claims a method for preparing SMA-13 ​​asphalt mixture, comprising the following steps: preheating coarse aggregate at 160~180℃ for 0.5~1.5h, preheating fine aggregate at 160~180℃ for 0.5~1.5h, and mixing for 60~180s to obtain an aggregate mixture; preheating SMA-13 ​​asphalt at 130~160℃ for 1~3h, and then adding it to the aggregate mixture, and mixing for 60~180s to obtain an intermediate mixture; preheating modified filler at 140~160℃ for 0.5~1.5h, adding it to the intermediate mixture, and stirring for 60~180s to obtain the SMA-13 ​​asphalt mixture.

[0028] The coarse aggregate is basalt with at least one of the following specifications: 3~5mm, 5~10mm, 10~15mm, and 10~20mm. The crushing value of the coarse aggregate is not greater than 28%, the apparent relative density is not less than 2.5, the water absorption rate is not greater than 3%, the adhesion to asphalt is not less than level 4, and the content of particles with a particle size less than 0.075mm as determined by the water washing method is not greater than 1%.

[0029] The fine aggregate is basalt with a size of 0~3mm, an apparent relative density of not less than 2.5, a methylene blue value of not more than 25g / kg, a sand equivalent of not less than 60%, and an angularity of not less than 30s.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. This invention provides an SMA-13 ​​asphalt mixture. SMA-13 ​​asphalt serves as the base binder, providing excellent adhesion and film-forming properties. The modified filler, phosphogypsum, utilizes industrial byproducts and undergoes a hardening reaction with quicklime, neutralizing the acidity of the phosphogypsum and forming a network structure with a certain strength, thus enhancing the early strength of the mixture. Limestone, as an aggregate filler, improves the volume stability and water damage resistance of the mixture. Modified basalt fibers enhance and disperse stress and inhibit crack propagation; simultaneously, their surface-active groups form chemical bonds with the asphalt, improving interfacial bonding strength. The coarse basalt aggregate, with its high hardness and excellent crushing value, forms a robust skeleton structure, bearing the main load-bearing capacity; while the fine aggregate effectively fills the gaps in the skeleton, improving overall density. This optimized mix design gives the asphalt mixture excellent high-temperature stability, low-temperature crack resistance, water stability, and fatigue durability, making it particularly suitable for road paving under heavy traffic and extreme weather conditions.

[0032] 2. This invention provides a modified basalt fiber that achieves multiple synergistic functions through a three-step surface modification process. First, the piperazine group, as a nitrogen-containing heterocyclic compound, has significant antioxidant capacity, effectively capturing free radicals generated during asphalt aging and blocking oxidation chain reactions. Simultaneously, its alkaline properties neutralize acidic components in asphalt, reducing the rate of acid value increase during aging, thus maintaining the long-term stability of the modified asphalt mixture under ultraviolet radiation and atmospheric oxidation conditions, delaying asphalt hardening and embrittlement. Second, the phosphite group can decompose and release phosphorus free radicals, rapidly terminating thermal oxidation chain reactions and reacting with oxygen free radicals to form stable phosphate esters, breaking oxidation chains and effectively decomposing peroxides accumulated during asphalt aging. Furthermore, it has a certain resistance to ultraviolet degradation, capturing free radicals generated by ultraviolet radiation and slowing down the photo-oxidation process on the asphalt surface. The phosphite group and piperazine group can also form a synergistic antioxidant system, constructing a comprehensive and long-lasting aging protection network. Simultaneously, in fire conditions, it can form a carbonized protective layer, endowing the material with certain flame-retardant properties. Third, the introduction of epoxy-based SBS achieves a "bridging" effect between basalt fibers and asphalt. The epoxy groups undergo ring-opening addition reactions with polar groups such as carboxyl and hydroxyl groups in the asphalt, forming chemical bonds. Meanwhile, the non-polar segments of SBS have good compatibility with the alkane components of the asphalt. This amphiphilic structure significantly improves the bonding strength of the fiber-asphalt interface and reduces interfacial debonding. At the same time, the SBS elastomer network endows the asphalt mixture with higher elastic recovery and rutting resistance, improving the low-temperature flexibility and fatigue crack resistance of the mixture. Overall, this multifunctional modified basalt fiber, used in conjunction with traditional fillers, constructs a composite reinforcement system that combines rigidity, flexibility, and toughness, effectively improving the comprehensive service performance and service life of asphalt mixtures, especially under conditions of drastic temperature fluctuations and heavy traffic. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Of course, the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0034] Unless otherwise specified, all chemical reagents and materials in this invention are purchased from the market or synthesized from raw materials purchased from the market.

[0035] The preparation method of epoxy group SBS includes the following steps: Take 13g of styrene and 500g of cyclohexane, stir and heat to 60℃, add 0.6mL of n-butyllithium, stir for 35min, add 60g of butadiene, react for 45min, add 13g of styrene, react for 30min, add 0.2mL of propylene oxide, react for 12min, add 0.3mL of epichlorohydrin, react for 15min, polymerize and dry to obtain epoxy group SBS.

[0036] The basalt fiber was purchased from Wuhan Qixing New Technology Materials Co., Ltd., with a length of 10~30mm, a diameter of 13~17μm, and a compressive strength ≥1050MPa.

[0037] A method for preparing SMA-13 ​​asphalt mixture includes the following steps:

[0038] (1) Clean 10g of basalt fiber with acetone and deionized water by ultrasonication for 10-20min, then immerse it in 150-200mL of ethanol aqueous solution (ethanol to deionized water volume ratio of 80-90:10-20), add 4-8g of 3-piperazinylpropylmethyldimethoxysilane, adjust the pH of the system to 4-5 with glacial acetic acid, stir the reaction at 60-75℃ for 3-6h, filter, wash and dry the product to obtain pretreated fiber;

[0039] (2) Disperse 10g of pretreated fiber into 100-150mL of xylene, then add 2-3.5g of diethyl 2-allyl phosphite, add 0.02-0.05g of BPO dropwise under a nitrogen atmosphere, reflux at 65-80℃ for 4-7h, filter the product, wash with acetone and THF 2-3 times in sequence, and dry to obtain intermediate fiber;

[0040] (3) Disperse 10g of intermediate fiber into 100-120mL of DMF / THF solvent (the volume ratio of DMF to THF is 7-8:2-3), then add 3-7g of epoxy SBS and 0.05-0.2g of triethylamine, stir evenly, reflux at 200-400r / min and 75-90℃ for 7-10h, filter the product, wash it with THF and ethanol 2-3 times in sequence, and dry it to obtain modified basalt fiber;

[0041] (4) Mix 10 parts phosphogypsum, 5-8 parts quicklime, 5-60 parts limestone, and 10-30 parts modified basalt fiber at 50-80 r / min for 60-180 s to obtain modified filler; preheat 50-80 parts basalt coarse aggregate at 160-180℃ for 0.5-1.5 h, preheat 20-50 parts basalt fine aggregate at 160-180℃ for 0.5-1.5 h, and mix for 60-180 s to obtain aggregate mixture; preheat 4-8 parts SMA-13 ​​asphalt at 130-160℃ for 1-3 h, and then add it to the aggregate mixture, and mix for 60-180 s to obtain intermediate mixture; preheat 4-8 parts modified filler at 140-160℃ for 0.5-1.5 h, add it to the intermediate mixture, and stir for 60-180 s to obtain the SMA-13 ​​asphalt mixture.

[0042] The present invention will be further described below through specific embodiments.

[0043] Example 1

[0044] A method for preparing SMA-13 ​​asphalt mixture includes the following steps:

[0045] (1) 10g of basalt fiber was ultrasonically cleaned with acetone and deionized water for 15min in sequence, and then immersed in 150mL of ethanol aqueous solution (the volume ratio of ethanol to deionized water was 90:10). 8g of 3-piperazinylpropylmethyldimethoxysilane was added, and the pH of the system was adjusted to 4.5 with glacial acetic acid. The reaction was stirred at 75℃ for 3h. The product was filtered, washed and dried to obtain pretreated fiber.

[0046] (2) Disperse 10g of pretreated fiber into 120mL of xylene, then add 3.5g of diethyl 2-allyl phosphite, add 0.05g of BPO dropwise under a nitrogen atmosphere, reflux at 80℃ for 4h, filter the product, wash twice with acetone and THF, and dry to obtain intermediate fiber;

[0047] (3) Disperse 10g of intermediate fiber into 100mL of DMF / THF solvent (the volume ratio of DMF to THF is 7:3), then add 7g of epoxy SBS and 0.2g of triethylamine, stir evenly, reflux at 400r / min and 90℃ for 7h, filter the product, wash it twice with THF and ethanol in sequence, and dry it to obtain modified basalt fiber;

[0048] (4) Mix 10g phosphogypsum, 8g quicklime, 60g limestone and 30g modified basalt fiber at 60r / min for 120s to obtain modified filler; preheat 800g basalt coarse aggregate at 170℃ for 1h and 500g basalt fine aggregate at 170℃ for 1h, mix for 120s to obtain aggregate mixture; preheat 80g SMA-13 ​​asphalt at 150℃ for 2h, then add it to aggregate mixture, mix for 120s to obtain intermediate mixture; preheat 80g modified filler at 150℃ for 1h, add it to intermediate mixture, stir for 120s to obtain SMA-13 ​​asphalt mixture.

[0049] Example 2

[0050] A method for preparing SMA-13 ​​asphalt mixture includes the following steps:

[0051] (1) 10g of basalt fiber was ultrasonically cleaned with acetone and deionized water for 15min in sequence, and then immersed in 150mL of ethanol aqueous solution (the volume ratio of ethanol to deionized water was 90:10). 6g of 3-piperazinylpropylmethyldimethoxysilane was added, and the pH of the system was adjusted to 4.5 with glacial acetic acid. The reaction was stirred at 70℃ for 4h. The product was filtered, washed and dried to obtain pretreated fiber.

[0052] (2) Disperse 10g of pretreated fiber into 120mL of xylene, then add 3.0g of diethyl 2-allyl phosphite, add 0.04g of BPO dropwise under a nitrogen atmosphere, reflux at 75℃ for 5h, filter the product, wash twice with acetone and THF, and dry to obtain intermediate fiber;

[0053] (3) Disperse 10g of intermediate fiber into 100mL of DMF / THF solvent (the volume ratio of DMF to THF is 7:3), then add 6g of epoxy SBS and 0.15g of triethylamine, stir evenly, reflux at 300r / min and 85℃ for 8h, filter the product, wash it twice with THF and ethanol in sequence, and dry it to obtain modified basalt fiber;

[0054] (4) Mix 10g phosphogypsum, 7g quicklime, 40g limestone and 25g modified basalt fiber at 60r / min for 120s to obtain modified filler; preheat 700g basalt coarse aggregate at 170℃ for 1h and 400g basalt fine aggregate at 170℃ for 1h, mix for 120s to obtain aggregate mixture; preheat 70g SMA-13 ​​asphalt at 150℃ for 2h, then add it to aggregate mixture, mix for 120s to obtain intermediate mixture; preheat 40~80g modified filler at 150℃ for 1h, add it to intermediate mixture, stir for 120s to obtain SMA-13 ​​asphalt mixture.

[0055] Example 3

[0056] A method for preparing SMA-13 ​​asphalt mixture includes the following steps:

[0057] (1) 10g of basalt fiber was ultrasonically cleaned with acetone and deionized water for 15min in sequence, and then immersed in 150mL of ethanol aqueous solution (the volume ratio of ethanol to deionized water was 90:10). 5g of 3-piperazinylpropylmethyldimethoxysilane was added, and the pH of the system was adjusted to 4.5 with glacial acetic acid. The reaction was stirred at 65℃ for 5h. The product was filtered, washed and dried to obtain pretreated fiber.

[0058] (2) Disperse 10g of pretreated fiber into 120mL of xylene, then add 2.5g of diethyl 2-allyl phosphite, add 0.03g of BPO dropwise under a nitrogen atmosphere, reflux at 70℃ for 6h, filter the product, wash twice with acetone and THF, and dry to obtain intermediate fiber;

[0059] (3) Disperse 10g of intermediate fiber into 100mL of DMF / THF solvent (the volume ratio of DMF to THF is 7:3), then add 4g of epoxy SBS and 0.1g of triethylamine, stir evenly, reflux at 300r / min and 80℃ for 9h, filter the product, wash it twice with THF and ethanol in sequence, and dry it to obtain modified basalt fiber;

[0060] (4) Mix 10g phosphogypsum, 6g quicklime, 20g limestone and 15g modified basalt fiber at 60r / min for 120s to obtain modified filler; preheat 600g basalt coarse aggregate at 170℃ for 1h and 300g basalt fine aggregate at 170℃ for 1h, mix for 120s to obtain aggregate mixture; preheat 50g SMA-13 ​​asphalt at 150℃ for 2h, then add it to aggregate mixture, mix for 120s to obtain intermediate mixture; preheat 50g modified filler at 150℃ for 1h, add it to intermediate mixture, stir for 120s to obtain SMA-13 ​​asphalt mixture.

[0061] Example 4

[0062] A method for preparing SMA-13 ​​asphalt mixture includes the following steps:

[0063] (1) 10g of basalt fiber was ultrasonically cleaned with acetone and deionized water for 15min in sequence, and then immersed in 150mL of ethanol aqueous solution (the volume ratio of ethanol to deionized water was 90:10). 4g of 3-piperazinylpropylmethyldimethoxysilane was added, and the pH of the system was adjusted to 4.5 with glacial acetic acid. The reaction was stirred at 60℃ for 6h. The product was filtered, washed and dried to obtain pretreated fiber.

[0064] (2) Disperse 10g of pretreated fiber into 120mL of xylene, then add 2g of diethyl 2-allyl phosphite, add 0.02g of BPO dropwise under a nitrogen atmosphere, reflux at 65℃ for 7h, filter the product, wash twice with acetone and THF, and dry to obtain intermediate fiber;

[0065] (3) Disperse 10g of intermediate fiber into 100mL of DMF / THF solvent (the volume ratio of DMF to THF is 7:3), then add 3g of epoxy SBS and 0.05g of triethylamine, stir evenly, reflux at 200r / min and 75℃ for 10h, filter the product, wash it twice with THF and ethanol in sequence, and dry it to obtain modified basalt fiber;

[0066] (4) Mix 10g phosphogypsum, 5g quicklime, 5g limestone and 10g modified basalt fiber at 60r / min for 120s to obtain modified filler; preheat 500g basalt coarse aggregate at 170℃ for 1h and 200g basalt fine aggregate at 170℃ for 1h, mix for 120s to obtain aggregate mixture; preheat 40g SMA-13 ​​asphalt at 150℃ for 2h, then add it to aggregate mixture, mix for 120s to obtain intermediate mixture; preheat 40g modified filler at 150℃ for 1h, add it to intermediate mixture, stir for 120s to obtain SMA-13 ​​asphalt mixture.

[0067] Comparative Example 1

[0068] A method for preparing SMA-13 ​​asphalt mixture includes the following steps:

[0069] (1) 10g of basalt fiber was ultrasonically cleaned with acetone and deionized water for 15min in sequence, and then immersed in 150mL of ethanol aqueous solution (the volume ratio of ethanol to deionized water was 90:10). 8g of 3-piperazinylpropylmethyldimethoxysilane was added, and the pH of the system was adjusted to 4.5 with glacial acetic acid. The reaction was stirred at 75℃ for 3h. The product was filtered, washed and dried to obtain pretreated fiber.

[0070] (2) Disperse 10g of pretreated fiber into 120mL of xylene, then add 3.5g of diethyl 2-allyl phosphite, add 0.05g of BPO dropwise under a nitrogen atmosphere, reflux at 80℃ for 4h, filter the product, wash twice with acetone and THF, and dry to obtain intermediate fiber;

[0071] (3) Mix 10g phosphogypsum, 8g quicklime, 60g limestone and 30g intermediate fiber at 60r / min for 120s to obtain modified filler; preheat 800g basalt coarse aggregate at 170℃ for 1h and 500g basalt fine aggregate at 170℃ for 1h, mix for 120s to obtain aggregate mixture; preheat 80g SMA-13 ​​asphalt at 150℃ for 2h, then add it to aggregate mixture, mix for 120s to obtain intermediate mixture; preheat 80g modified filler at 150℃ for 1h, add it to intermediate mixture, stir for 120s to obtain SMA-13 ​​asphalt mixture.

[0072] Comparative Example 2

[0073] A method for preparing SMA-13 ​​asphalt mixture includes the following steps:

[0074] (1) 10g of basalt fiber was ultrasonically cleaned with acetone and deionized water for 15min in sequence, and then immersed in 150mL of ethanol aqueous solution (the volume ratio of ethanol to deionized water was 90:10). 8g of 3-piperazinylpropylmethyldimethoxysilane was added, and the pH of the system was adjusted to 4.5 with glacial acetic acid. The reaction was stirred at 75℃ for 3h. The product was filtered, washed and dried to obtain pretreated fiber.

[0075] (2) Mix 10g phosphogypsum, 8g quicklime, 60g limestone and 30g pretreated fiber at 60r / min for 120s to obtain modified filler; preheat 800g basalt coarse aggregate at 170℃ for 1h and 500g basalt fine aggregate at 170℃ for 1h, mix for 120s to obtain aggregate mixture; preheat 80g SMA-13 ​​asphalt at 150℃ for 2h, then add it to aggregate mixture, mix for 120s to obtain intermediate mixture; preheat 80g modified filler at 150℃ for 1h, add it to intermediate mixture, stir for 120s to obtain SMA-13 ​​asphalt mixture.

[0076] The performance of the asphalt mixtures prepared in Examples 1-4 and Comparative Examples 1-2 was tested. Marshall stability and residual stability after immersion were determined according to T0709-2011; freeze-thaw splitting strength ratio was determined according to T0729-2000; and dynamic stability was determined according to T0729-2000. The specimens underwent accelerated aging at 65°C and 85% humidity for 1000 hours, followed by UV irradiation of 100 μw / cm². 2 After aging, the above experiments were repeated to evaluate the effect of aging on the performance of asphalt mixtures. Specific data are shown in Table 1.

[0077] Table 1. Results of Asphalt Mixture Performance Tests

[0078]

[0079] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A modified filler characterized in that, The modified filler is prepared by the following steps: (1) cleaning basalt fiber, then immersing the basalt fiber into an ethanol aqueous solution, adding 3-piperazinyl propyl methyl dimethoxy silane, adjusting pH of the system, stirring and reacting, filtering, washing and drying the product to obtain pretreated fiber; (2) dispersing the pretreated fiber into dimethylbenzene, then adding 2-allyl phosphite diethyl ester, dropping BPO under nitrogen atmosphere, refluxing and reacting, filtering, washing and drying the product to obtain intermediate fiber; and (3) dispersing the intermediate fiber into DMF / THF solvent, then adding epoxy SBS and triethylamine, stirring uniformly, refluxing and reacting, filtering, washing and drying the product to obtain the modified basalt fiber. In step (1), the basalt fiber is cleaned with acetone and deionized water under ultrasonic cleaning for 10-20 min; the pH of the system is adjusted to 4-5 with glacial acetic acid; and the stirring and reacting is performed at 60-75 DEG C for 3-6 h. In step (1), the basalt fiber, the ethanol aqueous solution, and the 3-piperazinyl propyl methyl dimethoxy silane are used in a ratio of 10 g: 150-200 mL: 4-8 g; and the ethanol aqueous solution contains ethanol and deionized water in a volume ratio of 80-90: 10-20. In step (2), the pretreated fiber, dimethylbenzene, 2-allyl phosphite diethyl ester, and BPO are used in a ratio of 10 g: 100-150 mL: 2-3.5 g: 0.02-0.05 g. In step (2), the refluxing and reacting is performed at 65-80 DEG C for 4-7 h; and the product is washed with acetone and THF for 2-3 times. In step (3), the intermediate fiber, DMF / THF solvent, epoxy SBS, and triethylamine are used in a ratio of 10 g: 100-120 mL: 3-7 g: 0.05-0.2 g; and the DMF / THF solvent contains DMF and THF in a volume ratio of 7-8: 2-3.

2. The modified filler of claim 1, wherein, In step (3), the refluxing and reacting is performed at 200-400 r / min and 75-90 DEG C for 7-10 h; and the product is washed with THF and ethanol for 2-3 times.

3. The modified filler of claim 1, wherein, The SMA-13 asphalt mixture is prepared by the following steps: preheating coarse aggregate at 160-180 DEG C for 0.5-1.5 h, preheating fine aggregate at 160-180 DEG C for 0.5-1.5 h, mixing for 60-180 s to obtain aggregate mixture; preheating SMA-13 asphalt at 130-160 DEG C for 1-3 h, then adding to the aggregate mixture, and mixing for 60-180 s to obtain intermediate mixture; preheating the modified filler at 140-160 DEG C for 0.5-1.5 h, adding to the intermediate mixture, and stirring for 60-180 s to obtain the SMA-13 asphalt mixture.

4. The modified filler of claim 1, wherein, ​ 5. The modified filler of claim 1, wherein, ​ 6. The modified filler of claim 1, wherein, ​ 7. An SMA-13 asphalt mixture comprising the modified filler of claim 1, characterized in that, ​ 8. The method of producing SMA-13 asphalt mixtures according to claim 7, characterized in that, ​

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