Asphalt mixture and preparation method thereof

Abstract

The invention discloses an asphalt mixture and a preparation method thereof. The raw materials of the asphalt mixture comprise the following components: 9-10 parts of emulsified asphalt, modified aggregate and a stabilizer, the modified aggregate is prepared from the following raw materials: 75 to 85 parts of aggregate and a binder solution; the aggregate comprises 40 to 50 parts of coarse aggregate with the particle size of 4.75 mm to 9.5 mm and 35 to 45 parts of fine aggregate with the particle size of 0.075 mm to 2.36 mm; a binder in the binder solution comprises an anionic surfactant; the stabilizer comprises a polyether type epoxy stabilizer. The asphalt mixture has excellent emulsion storage stability, adhesion of aggregate and asphalt and low-temperature crack resistance, effectively solves the problems of pavement potholes, looseness and other diseases caused by poor adhesion of aggregate and asphalt, and is beneficial to enhancing the durability and skid resistance of the pavement in rain wash, vehicle rolling and cold and humid environments; therefore, long-term stability of the road and driving safety are guaranteed.

Description

Technical Field

[0001] This invention relates to an asphalt mixture and its preparation method. Background Technology

[0002] Against the backdrop of modern transportation infrastructure construction and maintenance, road maintenance has become increasingly crucial. Among the technologies utilized, cold-mix asphalt paving, employing emulsified asphalt systems, has emerged as a leading approach, with slurry seal and micro-surfacing being representative examples. Emulsified asphalt cold-mix asphalt mixtures have garnered significant attention due to their substantial advantages. Construction does not require large-scale specialized hot-mix equipment and is not subject to excessive site or time constraints, allowing for flexible and convenient application in various road distress areas. More importantly, it can rapidly restore key functions such as road surface smoothness and skid resistance, enabling quick reopening to traffic after completion and minimizing disruption to traffic flow. The core of emulsified asphalt cold-mix asphalt mixture technology lies in the cold-mix asphalt mixture itself. A high-quality mixture can withstand long-term vehicle traffic and climate erosion, while also possessing a certain degree of skid resistance to ensure driving safety. It also effectively prevents rainwater infiltration, avoiding road surface structural damage such as loosening and potholes caused by water. However, with the current acceleration of urbanization and the explosive growth of traffic flow, coupled with the frequent passage of heavy and overloaded vehicles, the shortcomings of traditional slurry seal and micro-surfacing methods are becoming increasingly apparent. Under high-intensity operating conditions, its stability is poor, and it is prone to segregation and loosening; its anti-skid performance deteriorates rapidly, and it cannot continuously provide reliable grip for vehicles; its waterproof barrier is easily damaged, resulting in frequent road damage and making it difficult to meet the complex and ever-changing traffic demands of today.

[0003] Existing technologies mostly use conventional emulsified asphalt combined with base stabilizers, such as common cellulose stabilizers. The disclosed mixtures are mainly composed of ordinary emulsified asphalt, aggregates and a certain amount of cellulose stabilizers. The technical solutions focus on the simple combination of conventional materials and produce mixtures through ordinary mixing processes. In terms of technical effects, although basic cold-mix cold-paving construction can be achieved, the following shortcomings exist: (1) poor emulsion storage stability. Under high temperature conditions, the emulsion is prone to demulsification, and the storage period is usually insufficient; (2) poor adhesion between aggregates and asphalt, which makes the road surface prone to potholes, loosening and other defects under rainwater erosion and vehicle rolling; (3) insufficient low-temperature crack resistance. The road surface is very prone to cracking in cold regions, which seriously affects the service life of the road. Summary of the Invention

[0004] To address the aforementioned problems with existing cold-mix asphalt mixtures, this invention provides an asphalt mixture and its preparation method. The asphalt mixture exhibits excellent emulsion storage stability, aggregate-asphalt adhesion, and low-temperature crack resistance. It effectively solves the problems of potholes and looseness caused by poor aggregate-asphalt adhesion, and enhances the durability and skid resistance of the pavement under rain erosion, vehicle pressure, and cold and humid conditions. This improves the overall performance of cold-mix asphalt mixtures, ensuring long-term road stability and driving safety.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides an asphalt mixture, the raw materials of which include the following components:

[0007] 9-10 parts emulsified asphalt, modified aggregate and stabilizer;

[0008] The modified aggregate comprises 75-85 parts of aggregate and a binder; the aggregate comprises 40-50 parts of coarse aggregate with a particle size of 4.75mm-9.5mm and 35-45 parts of fine aggregate with a particle size of 0.075mm-2.36mm; the binder comprises anionic surfactant, and the amount of binder is 0.3%-0.5%, where the percentage is the mass percentage of the binder to the aggregate;

[0009] The stabilizer includes a polyether-type epoxy stabilizer, and the amount of the stabilizer is 1.0%-2.5%, where the percentage is the mass percentage of the stabilizer to the emulsified asphalt.

[0010] The aggregate gradation described in this invention is a continuous gradation, which improves density (+5.5%) and impermeability (permeability coefficient reduced by 57%) by optimizing the ratio of coarse and fine aggregates, and enhances anti-slip performance by 11.5%. The higher proportion of coarse aggregate and sufficient filling of fine aggregate result in a smaller structural porosity and significantly better performance than aggregates with conventional gradation.

[0011] In some preferred embodiments, the amount of coarse aggregate used is 45-50 parts.

[0012] In some preferred embodiments, the amount of fine aggregate is 35-45 parts.

[0013] In some preferred embodiments, the aggregate comprises 45-50 parts of coarse aggregate with a particle size of 4.75 mm-9.5 mm and 35-45 parts of fine aggregate with a particle size of 0.075 mm-2.36 mm.

[0014] In some preferred embodiments, the coarse aggregate comprises basalt.

[0015] In some preferred embodiments, the coarse aggregate is basalt.

[0016] In some preferred embodiments, the fine aggregate comprises manufactured sand.

[0017] In some preferred embodiments, the fine aggregate is manufactured sand.

[0018] In some specific implementations, the coarse aggregate is basalt, and the fine aggregate is manufactured sand.

[0019] In some preferred embodiments, the aggregate has a continuous gradation; preferably, the continuous gradation of the aggregate is as follows: 95%-100% passing through a 9.5mm sieve, for example, 98.7%; 75%-90% passing through a 4.75mm sieve, for example, 83.8%; 45%-70% passing through a 2.36mm sieve, for example, 58.7%; 25%-50% passing through a 1.18mm sieve, for example, 38.4%; 15%-35% passing through a 0.6mm sieve, for example, 25.2%; 8%-20% passing through a 0.3mm sieve, for example, 14.9%; 3%-12% passing through a 0.15mm sieve, for example, 8.5%; and 1%-8% passing through a 0.075mm sieve, for example, 5.3%. In this preferred scheme, by controlling the particle size distribution within different ranges, a stable and effective interlocking structure can be formed in the road structure, which can effectively bear traffic loads; while the fine aggregate, with its small particle characteristics, fills the gaps between the coarse aggregate, ensuring the overall density of the mixture and strengthening the structural strength.

[0020] In some specific implementations, the aggregate has a continuous gradation, which is defined as follows:

[0021] The passing rates for sieves with apertures of 9.5mm were 98.7%, 4.75mm 83.8%, 2.36mm 58.7%, 1.18mm 38.4%, 0.6mm 25.2%, 0.3mm 14.9%, 0.15mm 8.5%, and 0.075mm 5.3%.

[0022] In some embodiments, the absorbance of the modified aggregate is 0.10-0.20, for example, 0.11, 0.12, 0.13, 0.14, 0.17, or 0.18. The change in absorbance of the modified aggregate reflects the adsorption of the binder on the aggregate surface. Lower absorbance indicates better adsorption of the binder on the aggregate surface, resulting in more effective modification of the aggregate surface properties. When the binder is fully adsorbed on the aggregate surface, its ionized anions undergo ion exchange adsorption with the cations on the aggregate surface, increasing the negative charge on the aggregate surface. This enhances the electrostatic attraction and hydrogen bonding with the cationic emulsifier in the asphalt and the polar functional groups in the asphalt matrix, thereby improving the adhesion between the aggregate and the asphalt.

[0023] In some implementations, the stripping loss rate of the modified aggregate is 3%-6.5%, for example, 3.1%, 3.2%, 3.4%, 4.7%, 5.0%, or 6.2%. The stripping loss rate of the modified aggregate directly reflects the strength of the adhesion between the aggregate and asphalt. A lower stripping loss rate indicates less aggregate stripping from the asphalt when subjected to external factors (such as rainwater erosion or vehicle compaction), meaning stronger adhesion between the aggregate and asphalt.

[0024] In some embodiments, the zeta potential of the coarse aggregate in the modified aggregate is 19-30 mV, for example, 19.1 mV, 20.7 mV, 23.5 mV, 24.8 mV, 26.2 mV, 27.8 mV, or 28.3 mV. The zeta potential of the aggregate reflects the charge characteristics of the particle surface. An increase in the absolute value of the zeta potential of both coarse and fine aggregates in the modified aggregate indicates an increase in the surface charge density of the aggregate. This enhances the electrostatic force between the aggregate and the asphalt, promoting their adhesion.

[0025] In some embodiments, the Marshall stability of the coarse aggregate in the modified aggregate is 13-17 kN, for example, 13.30 kN, 13.75 kN, 14.52 kN, 14.65 kN, 15.23 kN, 15.89 kN, or 16.48 kN. The Marshall stability of the coarse aggregate in the modified aggregate is used to measure the ability of the asphalt mixture to resist damage at high temperatures, and also indirectly reflects the adhesion between the aggregate and the asphalt. Higher stability indicates a stronger bond between the aggregate and the asphalt, and better overall performance of the mixture.

[0026] In some embodiments, the zeta potential of the fine aggregate in the modified aggregate is 14-21 mV, for example, 14.5 mV, 16.8 mV, 17.6 mV, 18.3 mV, 19.2 mV, 19.8 mV or 20.1 mV.

[0027] In some embodiments, the bulk density of the fine aggregate in the modified aggregate is 2.5-2.6 g / cm³. 3 For example, 2.530 g / cm³ 3 2.554 g / cm 3 2.558 g / cm 3 2.564 g / cm 3 2.572 g / cm 3 2.575 g / cm 3 2.578 g / cm 3 Or 2.587 g / cm 3 The bulk density of the fine aggregate in the modified aggregate reflects its filling state in the asphalt mixture. When the bulk density increases, it indicates that the fine aggregate fills the voids in the coarse aggregate more tightly, resulting in improved compactness and stability of the asphalt mixture.

[0028] In some preferred embodiments, the amount of the stabilizer is 1.5%-2.5%, for example 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3% or 2.4%.

[0029] In some preferred embodiments, the polyether-type epoxy stabilizer includes polyethylene glycol diglycidyl ether.

[0030] In some specific implementations, the stabilizer is polyethylene glycol diglycidyl ether. The molecular structure of polyethylene glycol diglycidyl ether contains special active groups that can chemically react with asphalt particles to form a protective film on the surface, inhibiting the risk of emulsion demulsification, extending shelf life, and solving the problem of high-temperature deterioration in traditional slurry seal and micro-surfacing mixtures. Simultaneously, it moderately reduces the emulsion viscosity, promotes uniform asphalt dispersion, overcomes uneven mixing, improves construction smoothness, and reduces construction costs and quality risks.

[0031] In some more preferred embodiments, the weight-average molecular weight of the polyethylene glycol diglycidyl ether is 300-500 g / mol, for example, 400 g / mol.

[0032] In some specific implementations, the polyethylene glycol diglycidyl ether was purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0033] In some preferred embodiments, the stabilizer further includes sodium silicate.

[0034] In some more preferred embodiments, the stabilizer comprises sodium silicate and polyethylene glycol diglycidyl ether, wherein the mass ratio of sodium silicate to polyethylene glycol diglycidyl ether is 1:(2-3). Preferably, the amount of sodium silicate is 0.5%-1.0%, and the amount of polyethylene glycol diglycidyl ether is 1.0%-1.5%, where the percentages are the mass percentages of each component relative to the emulsified asphalt.

[0035] In some preferred embodiments, the stabilizer has an epoxy value of 0.5-0.7 eq / 100g, preferably 0.58-0.64 eq / 100g.

[0036] In some preferred embodiments, the epoxy equivalent of the stabilizer is 150-170 g / eq, preferably 152-170 g / eq.

[0037] In some preferred embodiments, the hydrolyzable chlorine content of the stabilizer is not higher than 0.03 eq / 100g, preferably not higher than 0.02 eq / 100g.

[0038] In some preferred embodiments, the inorganic chlorine content of the stabilizer is not higher than 0.005 eq / 100g, preferably not higher than 0.003 eq / 100g.

[0039] In some preferred embodiments, the purity of the stabilizer is not less than 85%, preferably not less than 90%.

[0040] In some specific embodiments, the polyethylene glycol diglycidyl ether meets the following conditions: epoxy value of 0.58-0.64 eq / 100g; epoxy equivalent of 152-170 g / eq; hydrolyzable chlorine content of not more than 0.02 eq / 100g; inorganic chlorine content of not more than 0.003 eq / 100g; and purity of not less than 90%.

[0041] In some preferred embodiments, the amount of adhesive used is 0.35%-0.45%, for example, 0.40%.

[0042] In some preferred embodiments, the anionic surfactant comprises sodium tripolyphosphate and / or calcium lignosulfonate.

[0043] In some specific embodiments, the binder is sodium tripolyphosphate. Sodium tripolyphosphate is a key modifier, acting as a polyelectrolyte. In aqueous solution, it undergoes ion exchange adsorption with cations on the aggregate surface, altering the aggregate's charge characteristics, significantly enhancing adhesion to asphalt, and effectively preventing aggregate spalling and pavement potholes. Furthermore, it plays a dispersing role in the mixing process, optimizing aggregate distribution and improving workability.

[0044] In some specific embodiments, the binder is calcium lignosulfonate.

[0045] In some preferred embodiments, the phosphorus content in the binder is 55%-60%, preferably 57%-58%, where the percentage refers to the mass percentage of P2O5 in the binder.

[0046] In some preferred embodiments, the pH value of the adhesive is 8.0-10.0, preferably 9.0-10.0.

[0047] In some preferred embodiments, the water-insoluble content of the adhesive is less than 0.2%, preferably less than 0.1%.

[0048] In some preferred embodiments, the purity of the adhesive is not less than 90%, preferably not less than 95%.

[0049] In some preferred embodiments, the sodium tripolyphosphate satisfies the following conditions:

[0050] The phosphorus content is 57%-58%, where the percentage refers to the mass percentage of P2O5 in the binder; the pH value is 9.0-10.0; the water-insoluble content is less than 0.1%; and the purity is not less than 95%.

[0051] In some preferred embodiments, the adhesive solution is an aqueous adhesive solution.

[0052] In some more preferred embodiments, the adhesive solution is an aqueous solution of sodium tripolyphosphate, preferably with a concentration of 8%-14%, more preferably 10%-14%, for example 12%;

[0053] In some more preferred embodiments, the binder solution is an aqueous solution of calcium lignosulfonate, preferably with a concentration of 5%-10%.

[0054] In this invention, the raw materials of the asphalt mixture may also include a solvent, which may be a solvent commonly used in the art, such as water.

[0055] In some preferred embodiments, the emulsified asphalt is cationic emulsified asphalt. When the cationic emulsified asphalt is combined with aggregates, it can utilize electrostatic adsorption to allow asphalt particles to better adhere to the negatively charged aggregate surface, enhancing the adhesion effect. Compared with anionic emulsified asphalt, it can significantly improve the early strength and stability of the mixture, especially in the early stages of road maintenance, allowing for rapid restoration of pavement performance and meeting the needs of rapid traffic reopening.

[0056] In some preferred embodiments, the emulsified asphalt is modified emulsified asphalt. Modified emulsified asphalt refers to emulsified asphalt prepared by adding a polymer modifier to ordinary emulsified asphalt. Preferably, the polymer modifier includes one or more of rubber-based modifiers, resin-based modifiers, and thermoplastic elastomers.

[0057] In some preferred embodiments, the solid content of the emulsified asphalt is 50%-65%, more preferably 55%-65%, for example 60%.

[0058] In some preferred embodiments, the emulsified asphalt has a residue of less than 0.1% on a 1.18 mm sieve, more preferably 0.01%-0.05%, for example 0.015%, 0.02% or 0.03%.

[0059] In some preferred embodiments, the emulsified asphalt has a storage stability of less than 1.0% after being stored at 25°C for 1 day, more preferably 0.5%-0.95%, for example 0.6%, 0.7%, 0.8% or 0.9%.

[0060] In some preferred embodiments, the residual content of the emulsified asphalt is not less than 55%, more preferably 55%-65%, for example 55.5%, 61.5%, 63% or 64.5%.

[0061] In some preferred embodiments, the penetration of the emulsified asphalt at 25°C is (45-150) / 0.1mm, more preferably (60-85) / 0.1mm, for example 63.5 / 0.1mm, 65.5 / 0.1mm, 70.5 / 0.1mm, 80.5 / 0.1mm.

[0062] In some preferred embodiments, the softening point of the emulsified asphalt is not lower than 42°C, more preferably 42-55°C, for example 42°C, 47°C, 50°C or 52°C.

[0063] In some preferred embodiments, the emulsified asphalt has a ductility of not less than 40 mm at 25°C, more preferably 40-150°C, and even more preferably 100-150°C, for example 104 mm, 116 mm, 125 mm or 130 mm.

[0064] In some specific implementation schemes, the emulsified asphalt is purchased from Shanghai Chengjian Rili Special Asphalt Co., Ltd.

[0065] In some specific implementations, the emulsified asphalt is any one of the following numbers 1-4:

[0066] .

[0068] In some specific embodiments, the anionic surfactant is sodium tripolyphosphate, the polyether-type epoxy stabilizer is polyethylene glycol diglycidyl ether, the concentration of the binder solution is 5%-15%, the amount of the binder is 0.35%-0.45%, the amount of the stabilizer is 1.5%-2.5%, the coarse aggregate includes basalt, and the fine aggregate includes manufactured sand; the aggregate gradation is continuous gradation, and the continuous gradation of the aggregate is as follows:

[0069] The sieve aperture of 9.5mm has a throughput of 95%-100%, for example, 98.7%.

[0070] The sieve aperture of 4.75mm has a throughput of 75%-90%, for example, 83.8%.

[0071] The sieve aperture of 2.36mm has a throughput of 45%-70%, for example, 58.7%.

[0072] The sieve aperture of 1.18mm has a throughput of 25%-50%, for example, 38.4%.

[0073] The sieve aperture of 0.6mm has a throughput of 15%-35%, for example, 25.2%;

[0074] The sieve aperture of 0.3mm has a throughput of 8%-20%, for example, 14.9%.

[0075] The sieve aperture of 0.15mm has a throughput of 3%-12%, for example, 8.5%.

[0076] The pass rate for a sieve with a aperture of 0.075mm is 1%-8%, for example, 5.3%.

[0077] This invention provides a method for preparing the asphalt mixture as described above, comprising the following steps:

[0078] The modified aggregate, the emulsified asphalt, the stabilizer, and the solvent are mixed. In this invention, the solvent can be a solvent conventionally used in the art, such as water.

[0079] In some preferred embodiments, the method for preparing the modified aggregate includes the following steps:

[0080] S1. Preheat the aggregate to obtain preheated aggregate;

[0081] S2. Mix the preheated aggregate and the binder solution, and then dry them.

[0082] In step S1, the preheating temperature is preferably 100-130℃, for example, 120℃.

[0083] In step S1, the preheating time is preferably 2-4 hours, for example, 3 hours.

[0084] In step S2, the mixing temperature is preferably 40-60℃, for example, 50℃.

[0085] In step S2, the mixing time is preferably 15-50 min, more preferably 20-50 min, for example 30 min.

[0086] In some preferred embodiments, the discharge temperature of the asphalt mixture is 75-90°C, for example, 85°C.

[0087] In some preferred embodiments, the mixing includes the following steps:

[0088] The first mixture and the stabilizer are mixed to obtain a second mixture, and the second mixture is mixed with the solvent;

[0089] The first mixture comprises the emulsified asphalt and the modified aggregate; the preparation method of the first mixture preferably includes the following steps: spraying the emulsified asphalt onto the surface of the modified aggregate and stirring.

[0090] Preferably, the spraying time is 0.3-0.5 s / g, for example, 0.3 s / g. Here, s / g refers to the spraying time based on a unit mass of emulsified asphalt.

[0091] Preferably, the emulsified asphalt is sprayed while being stirred. The stirring device can be a conventional mixing plant in the art.

[0092] Preferably, the stirring speed is 110-130 r / min, for example 120 r / min.

[0093] Preferably, in the method for preparing the first mixture, the stirring time is 30-50 s, for example, 40 s.

[0094] In the preparation method of the second mixture, the stirring speed during mixing is preferably 110-130 r / min, for example 120 r / min; preferably, the stirring time is 30-50 s, for example 40 s.

[0095] When mixing the second mixture and the solvent, the stirring speed during the mixing is preferably 180-220 r / min, for example 200 r / min; preferably, the stirring time is 50-70 s, for example 60 s.

[0096] The asphalt mixture of this invention achieves excellent emulsion storage stability, aggregate-asphalt adhesion, and low-temperature crack resistance through the synergistic effect of multiple components in specific amounts, including emulsified asphalt, polyether-type epoxy stabilizer, and modified aggregate obtained by modifying with anionic surfactant. The synergistic effect between the components is manifested in the following aspects:

[0097] (1) Emulsified asphalt, as a basic bonding material, can provide viscosity and plasticity, effectively binding the components together;

[0098] (2) By specially preparing an anionic surfactant into a solution of appropriate concentration and soaking the aggregate, the aggregate is adsorbed onto the surface of the aggregate. The anions generated by the ionization of the anionic surfactant react with the Ca on the surface of the aggregate. 2+ Mg 2+ The process involves isoelectric exchange, which increases the absolute value of the zeta potential of the aggregate, altering its surface charge characteristics and thus obtaining modified aggregate. The electrostatic repulsion between the modified aggregate particles prevents particle aggregation, thereby enhancing the kinetic stability of the emulsion system. Furthermore, the special charge distribution on the surface of the modified aggregate further optimizes the compatibility of the emulsion-modified aggregate interface with the emulsion asphalt, enhancing the adhesion between the modified aggregate and asphalt. This allows for further optimization of the modified aggregate distribution during subsequent mixing, improving the workability of the mixture.

[0099] (3) Through the dual mechanism of chemical grafting and ion exchange adsorption of epoxy groups in polyether epoxy stabilizers, the epoxy groups in the molecular chain of polyether epoxy stabilizers undergo ring-opening crosslinking reaction with the polar functional groups of emulsified asphalt, forming a dense protective film with a thickness of about 50-100nm on the particle surface. Through the steric hindrance effect, the average spacing of particles in asphalt mixture is maintained at 200-300nm, effectively inhibiting the aggregation behavior caused by van der Waals forces.

[0100] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0101] The reagents and raw materials used in this invention are all commercially available.

[0102] The positive and progressive effects of this invention are as follows:

[0103] The asphalt mixture of the present invention, by introducing a polyether-type epoxy stabilizer and anionic surfactant, exhibits excellent emulsion storage stability, aggregate-asphalt adhesion, and low-temperature crack resistance, and can be used for cold mixing and cold paving. Specifically:

[0104] (1) Regarding the storage stability of the emulsion, by introducing polyether-type epoxy stabilizer, a protective film is formed on the surface of emulsified asphalt particles using its unique molecular structure, which prevents particle aggregation, reduces emulsion viscosity, and improves storage stability. This solves the problems of easy emulsion demulsification and short storage period at high temperatures, laying a solid foundation for the stability of material performance in the early stage of construction and reducing the risk of increased construction costs and reduced road quality due to material deterioration.

[0105] (2) Regarding the adhesion between aggregate and asphalt, modified aggregate is obtained by treating the aggregate with anionic surfactant. By changing the charge characteristics of the aggregate, the adhesion between the aggregate and asphalt is enhanced, which effectively solves the problems of poor adhesion between aggregate and asphalt, such as potholes and looseness of the road surface, and enhances the durability and anti-skid performance of the road surface under rain scouring, vehicle rolling and cold and humid environments.

[0106] (3) In terms of low-temperature crack resistance, the polyether-type epoxy stabilizer stabilizes the emulsion structure and the anionic surfactant enhances the adhesion between aggregate and asphalt, making the mixture structurally stable at low temperatures. This reduces road surface cracking in cold regions, lowers maintenance frequency and cost, and extends the service life of the road surface. It effectively overcomes the problem of insufficient low-temperature crack resistance of traditional mixtures, improves the service performance and stability of roads under complex traffic and harsh weather conditions, and comprehensively improves the overall performance of asphalt mixtures based on emulsified asphalt (especially as cold-mixed cold-laid asphalt mixtures) to meet the stringent requirements of modern traffic.

[0107] In addition, the preparation method of this asphalt mixture is simple, easy to operate, and low in cost. Detailed Implementation

[0108] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0109] The specific information regarding the emulsified asphalt, stabilizer, and binder used in the following examples and comparative examples is as follows:

[0110] (1) Emulsified asphalt: Cationic emulsified asphalt with a solid content of 50%-65% was selected. It is mainly composed of base asphalt, emulsifier, stabilizer and water, and was purchased from Shanghai Chengjian Rili Special Asphalt Co., Ltd. The technical indicators of cationic emulsified asphalt with different solid contents are shown in Table 1.

[0111] Table 1 Technical Specifications of Cationic Emulsified Asphalt with Different Solid Content

[0112]

[0113] (2) Stabilizer: Polyethylene glycol diglycidyl ether was selected and purchased from Shanghai Yuanye Biotechnology Co., Ltd., with a weight-average molecular weight M. W The concentration is 400 g / mol. Chemical parameters are shown in Table 2.

[0114]

[0115] (3) Adhesive: Sodium tripolyphosphate was selected and purchased from Hubei Wande Chemical Co., Ltd., model WD3226. Chemical properties are shown in Table 3.

[0116]

[0117] (4) Aggregates: Basalt is used as coarse aggregate, with a particle size range of 4.75mm-9.5mm. Manufactured sand is used as fine aggregate, with a particle size range of 0.075mm-2.36mm. Compared with natural sand, the particle shape and surface texture of manufactured sand are more conducive to adhesion with asphalt. See Table 4 for the gradation design.

[0118]

[0119] Example 1

[0120] 1. Preparation of modified aggregates:

[0121] ① Add sodium tripolyphosphate to deionized water at a mass ratio of (8:92), and stir with a magnetic stirrer at 400 r / min for 15 minutes to ensure that the sodium tripolyphosphate is fully dissolved, and prepare sodium tripolyphosphate aqueous solutions with a concentration of 8% respectively.

[0122] ② Place 45 parts of coarse aggregate and 40 parts of fine aggregate in an oven for preheating, raise the temperature to 120℃ and keep it at that temperature for 3 hours to remove moisture from the aggregate;

[0123] ③ Pour the preheated coarse aggregate and fine aggregate into the prepared sodium tripolyphosphate aqueous solution heated to 50°C, and soak them for 20 minutes. Stir with a glass rod every 6 minutes during this period to ensure that the coarse aggregate and fine aggregate are fully in contact with the sodium tripolyphosphate aqueous solution.

[0124] ④ After soaking, use a filter to remove the aggregate, let it drain naturally in a fume hood for 15 minutes, and then put it in a 100℃ oven to dry to constant weight. During the drying process, turn the aggregate over every 40 minutes to ensure uniform drying (it can be considered as water-free). Modified coarse aggregate and fine aggregate (referred to as modified aggregate) are obtained respectively.

[0125] 2. Preparation of asphalt mixture:

[0126] ① Raw material preparation: Weigh 9.09 parts of cationic emulsified asphalt, 0.09 parts of stabilizer polyethylene glycol diglycidyl ether, and 85 parts of modified aggregate.

[0127] ② Slowly add cationic emulsified asphalt to the mixing plant (addition rate: 150g / min), and simultaneously turn on the spraying device to evenly spray the emulsified asphalt onto the surface of the modified aggregate. The modified aggregate must be kept agitated. Simultaneously turn on the spraying device while stirring and spraying to ensure the emulsified asphalt evenly coats the surface of the modified aggregate, avoiding localized agglomeration; control the spraying time to 30 seconds to ensure good initial contact between the aggregate and the emulsified asphalt.

[0128] ③ Next, stir at 120 r / min for 40 seconds to allow the modified aggregate to fully coat the emulsified asphalt. During this process, pay attention to the state of the mixture to avoid clumping. The first mixture is obtained.

[0129] Then, polyethylene glycol diglycidyl ether is added, and the mixture is stirred at 120 rpm for 40 seconds to obtain the second mixture.

[0130] ④ Finally, add water accounting for 4% of the total mass of the second mixture, and stir rapidly at 200 r / min for 60 seconds to make the mixture uniform. Control the discharge temperature at 85℃ to complete the preparation of the asphalt mixture.

[0131] Example 2

[0132] The difference between Example 2 and Example 1 is that: in the preparation of the modified aggregate, ① the mass ratio of sodium tripolyphosphate and deionized water is 10:90, and a 10% sodium tripolyphosphate aqueous solution is prepared; ③ the soaking time is 30 minutes. All other conditions are the same as in Example 1.

[0133] Example 3

[0134] The difference between Example 3 and Example 1 is that: in the preparation of the modified aggregate, ① the mass ratio of sodium tripolyphosphate and deionized water is 12:88, and a 12% sodium tripolyphosphate aqueous solution is prepared; ③ the soaking time is 40 minutes. All other conditions are the same as in Example 1.

[0135] Example 4

[0136] The difference between Example 4 and Example 1 is that: in the preparation of the modified aggregate, ① the mass ratio of sodium tripolyphosphate and deionized water is 25:75, and a 14% sodium tripolyphosphate aqueous solution is prepared; ③ the soaking time is 50 minutes. All other conditions are the same as in Example 1.

[0137] Example 5

[0138] Based on Example 3, only the amount of stabilizer polyethylene glycol diglycidyl ether was changed to 1.0% of the mass of the emulsified asphalt, while the other conditions remained the same as in Example 3.

[0139] Example 6

[0140] Based on Example 3, only the cationic emulsified asphalt was replaced with rubber-modified emulsified asphalt (60% solid content, 5% rubber modifier, purchased from Shanghai Chengjian Rili Special Asphalt Co., Ltd.), and the other conditions were the same as in Example 3.

[0141] Example 7

[0142] Based on Example 3, only the sodium tripolyphosphate was replaced with calcium lignosulfonate, while the other conditions remained the same as in Example 3.

[0143] Example 8

[0144] Based on Example 3, the stabilizers used were sodium silicate (0.5% of the emulsified asphalt mass) and polyethylene glycol diglycidyl ether (1.5% of the emulsified asphalt mass), with a total stabilizer dosage of 2.0%, and the other conditions were the same as in Example 3.

[0145] Comparative Example 1

[0146] The difference between Comparative Example 1 and Example 1 is that no modified aggregate was prepared, and sodium tripolyphosphate was not added during the preparation of the asphalt mixture. All other conditions remained the same as in Example 1. Specifically, 45 parts coarse aggregate and 40 parts fine aggregate from Example 1 were directly mixed without any modification treatment to obtain the aggregate, which was then used to prepare the asphalt mixture.

[0147] Comparative Example 2

[0148] Asphalt mixtures incorporating 4% hydroxypropyl methylcellulose (HPMC) consist of emulsified asphalt, aggregates, and HPMC (as a stabilizer).

[0149] The preparation method of asphalt mixture includes the following steps:

[0150] 1. Raw material composition: Cationic emulsified asphalt (50% solid content): 10 parts by weight, accounting for 10% of the total mass of the asphalt mixture; aggregate: 85 parts by weight, accounting for 85% of the total mass of the asphalt mixture, including 45 parts of basalt coarse aggregate with a particle size of 4.75-9.5mm and 40 parts of manufactured sand fine aggregate with a particle size of 0.075-2.36mm (the specific gradation of coarse and fine aggregates is the same as that in Example 1); HPMC: 0.4 parts by weight, accounting for 4% of the mass of the emulsified asphalt; water: 5 parts by weight, accounting for 5% of the total mass of the asphalt mixture, used to adjust the workability of construction.

[0151] 2. Preparation method: ① Aggregate pretreatment: Coarse and fine aggregates are directly mixed without any modification treatment to obtain aggregates. ② Mixture mixing: Emulsified asphalt is added to the mixing plant and stirred at 120 r / min, while being sprayed onto the aggregate surface for 50 seconds; cellulose is added and stirring is continued for 60 seconds until the mixture is uniform; finally, water is added and rapidly stirred at 200 r / min for 30 seconds, with the discharge temperature controlled at 70-80℃.

[0152] Some parameters in Examples 1-5 are shown in Table 5.

[0153]

[0154] Example 1

[0155] The modified aggregates obtained in Examples 1-8 and the aggregates in Comparative Examples 1-2 were used as test samples for the following characterization:

[0156] (1) Absorbance

[0157] Weigh 5g of the sample to be tested, add 50mL of deionized water, and sonicate for 30 minutes (for modified aggregates, this can fully dissolve the adsorbed sodium tripolyphosphate); after standing, take the supernatant and measure the absorbance at a wavelength of 254nm using a UV-Vis spectrophotometer.

[0158] (2) Peeling resistance quality loss rate

[0159] The test sample was mixed with emulsified asphalt at a mass ratio of 5:1 to form a cylindrical specimen with a diameter of 25 mm, which was then cured at room temperature for 24 hours. The specimen was then immersed in a 60℃ water bath for 4 hours, and then rinsed with running water for 5 minutes (water flow rate of approximately 500 mL / min). After drying, the mass of the specimen was weighed, and the mass loss rate was calculated.

[0160]

[0161] (3) Zeta potential of coarse aggregate and Zeta potential of fine aggregate

[0162] Unmodified coarse aggregate, fine aggregate, and modified coarse aggregate and fine aggregate were used as test samples for testing. Specifically:

[0163] Take 2g of the sample to be tested and add it to 20mL of deionized water. Disperse it by sonication for 5 minutes to prepare a suspension. Use a Zeta potential analyzer to measure the Zeta potential of the particles in the suspension. Repeat the test 3 times for each group and take the average value. The results are expressed as absolute values. The larger the absolute value, the higher the surface charge density.

[0164] (4) Marshall stability of coarse aggregate

[0165] Unmodified coarse aggregate and modified coarse aggregate were used as test samples, respectively. Specifically:

[0166] Marshall specimens (101.6 mm in diameter and 63.5 mm in height) were prepared by mixing the test sample with emulsified asphalt at the optimal asphalt-aggregate ratio. The specimens were kept in a constant temperature water bath at 60°C for 30 minutes. The maximum load (unit: kN) at which the specimen failed was recorded using a Marshall stability tester at a rate of 50 mm / min.

[0167] (5) Bulk density of fine aggregate

[0168] Unmodified fine aggregate and modified fine aggregate were used as test samples, respectively. Specifically:

[0169] Weigh approximately 1000g of the dried sample to be tested and pour it into a volumetric flask (1L capacity) in three portions. After each pour, gently tap the flask wall to distribute the particles evenly. Continue pouring until the fine aggregate fills the flask, then smooth the surface and weigh the total mass (mass of fine aggregate = total mass - mass of volumetric flask). Calculate the bulk density (unit: g / cm³). 3 ):

[0170]

[0171] The test results are shown in Table 6.

[0172]

[0173] Note: The aggregates in Comparative Example 1 and Comparative Example 2 were not specially treated and were the same aggregates, so the results in the table above are consistent.

[0174] According to Table 6:

[0175] (1) Absorbance: The absorbance of the modified aggregates obtained in Examples 1-8 of this invention can be as low as 0.10-0.20, while the absorbance of the aggregates in Comparative Examples 1-2 is as high as 0.53. Taking Example 1 as an example, the following further explanation is given: The absorbance of the modified aggregates obtained by treating the aggregates with an 8% concentration of sodium tripolyphosphate aqueous solution in Example 1 is only 0.18, and the spalling mass loss rate is reduced; while the absorbance of the modified aggregates obtained in Comparative Example 1 without treating the aggregates with sodium tripolyphosphate aqueous solution is as high as 0.53; it can be seen from the comparison that the modified aggregates in Example 1 have better adhesion.

[0176] (2) Anti-stripping mass loss rate: The anti-stripping mass loss rate of the modified aggregates obtained in Examples 1-8 of this invention can be as low as 3.0%-6.2%, while the anti-stripping mass loss rate of the aggregates in Comparative Examples 1-2 is as high as 7.4%. Among them, in Examples 1-5, as the sodium tripolyphosphate concentration increases and the soaking time is prolonged, the anti-stripping mass loss rate gradually decreases from 7.4% to 3.0%, and the adhesion performance of the modified aggregates is relatively excellent. From the comparison between Examples 1-8 and Comparative Examples 1-2, it can be seen that the anti-stripping mass loss rate of the aggregates in the comparative examples is higher and the adhesion performance is poorer.

[0177] (3) Zeta potential of coarse aggregate and fine aggregate: The Zeta potential of coarse aggregate in the modified aggregates obtained in Examples 1-8 can reach 19.1-28.3 mV, and the Zeta potential of fine aggregate can reach 14.0-20.1 mV. In particular, the Zeta potential of coarse aggregate in the modified aggregate obtained in Example 4 can even reach 28.3 mV, and the Zeta potential of fine aggregate can reach 20.1 mV. This indicates that under the action of charge, the aggregate and asphalt are more tightly bonded and the adhesion is improved. However, the Zeta potential of coarse aggregate in the aggregates obtained in Comparative Examples 1-2 is only 8.3 mV, and the Zeta potential of fine aggregate is only 6.4 mV, indicating poor adhesion performance of the aggregate.

[0178] (4) Marshall stability of coarse aggregate: The Marshall stability of coarse aggregate in the modified aggregates obtained in Examples 1-8 of this invention can reach 13.30-16.48 kN. However, the Marshall stability of coarse aggregate in the aggregates in Comparative Examples 1-2 is only 12.34 kN. This indicates that the adhesion between the aggregates and asphalt in Examples 1-8 is enhanced, making the mixture more stable when subjected to external forces and less prone to damage. Overall, the stability is better.

[0179] (5) Bulk density of fine aggregate: Compared with the conventional aggregate in Comparative Examples 1-2, the bulk density of fine aggregate is only 2.426 g / cm³. 3 In the modified aggregates used in Examples 1-8 of this invention, the bulk density of the fine aggregates is significantly higher (2.530-2.587 g / cm³). 3 This indicates that the fine aggregate in the asphalt mixture obtained in the embodiments of the present invention fills the voids in the coarse aggregate more tightly, thereby improving the density and stability of the mixture.

[0180] Example 2

[0181] The emulsion storage stability, adhesion, and low-temperature crack resistance of the asphalt mixtures obtained in Examples 1-8 and Comparative Examples 1-2 were tested using the following specific test methods:

[0182] (1) Emulsion storage stability test: The prepared asphalt mixture samples were placed in a constant temperature chamber and the temperature was set at 32℃ (under ambient humidity). Every 10 days, the samples were taken out to test their storage stability and evaporation residue. The presence of signs of emulsion demulsification was observed. If precipitation or flocculation occurred, the demulsification time was recorded. The viscosity of the emulsion was measured regularly using a Brookfield viscometer to monitor the viscosity change trend and determine the impact of emulsion stability on workability.

[0183] The specific test methods for storage stability, evaporation residue, and demulsification time are as follows:

[0184] Storage stability testing was conducted using centrifugation to calculate the percentage of the separated aqueous phase volume relative to the total sample volume.

[0185] Evaporation residue detection: The sample is heated and evaporated to constant weight at a specified temperature, the mass of the residue is weighed and the percentage of its original mass to the mass of the sample is calculated;

[0186] Demulsification time: The time when the emulsion begins to show signs of demulsification such as precipitation and flocculation is recorded as the demulsification time, which is also the number of days to stabilize.

[0187] The test results are shown in Table 7.

[0188] (2) Aggregate-asphalt adhesion test: Marshall specimens were prepared according to the standard method specified in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTJ052-2000). The specimen dimensions were 101.6±0.2 mm in diameter and 63.5±1.3 mm in height. The boiling method was used for the experiment, which included the following steps: the Marshall specimens were placed in boiling water and boiled for 30 minutes. After that, the specimens were removed and the aggregate spalling was observed. The spalling area ratio was calculated using ImageJ image analysis software to evaluate the adhesion effect between the aggregates and asphalt. At the same time, a freeze-thaw splitting test was conducted. The specimens were subjected to 5 freeze-thaw cycles (freezing temperature of -15℃, freezing time of 16h, thawing temperature of 20℃, thawing time of 24h), and then the splitting strength ratio, average pull-out force, and skid resistance attenuation rate were tested to simulate the adhesion performance under cold and humid conditions.

[0189] The specific test methods for freeze-thaw splitting strength ratio, average pull-out force, and anti-slip attenuation rate are as follows:

[0190] The freeze-thaw splitting strength ratio test was conducted using a universal testing machine. The splitting failure load of the specimen before and after freeze-thaw cycles was recorded, and the freeze-thaw splitting strength ratio was calculated. The formula for calculating the freeze-thaw splitting strength ratio is as follows:

[0191]

[0192] Where: 𝑇𝑆𝑅—freeze-thaw splitting strength ratio (%);

[0193] R1—Splitting strength (MPa) of specimens that have not undergone freeze-thaw cycles;

[0194] R2—Splitting strength (MPa) of the specimen after 5 freeze-thaw cycles.

[0195] The average pull-out force test was conducted using a pull-out tester. The pull-out head was bonded to the specimen, and a tensile force was applied at a constant rate. The force value at the point of pull-out failure was recorded.

[0196] The anti-skid attenuation test uses accelerated abrasion testing equipment to simulate the wear and tear on the road surface caused by vehicle travel. The pendulum value of the specimen is measured before the abrasion test and after 2520 abrasion cycles, and the anti-skid attenuation rate is calculated. The formula for calculating the anti-skid attenuation rate is:

[0197]

[0198] Where: B0—the pendulum value of the specimen before the wear test (BPN);

[0199] B n —The pendulum value (BPN) of the specimen after 2520 wear cycles.

[0200] The test results are shown in Table 8.

[0201] (3) Low-temperature crack resistance test: Using a low-temperature test chamber, set to -10℃, prepare rutting plate specimens according to the standard method specified in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTJ052-2000). The specimen size is 300mm×300mm×50mm, and the following tests are carried out at -10℃:

[0202] ① Apply simulated vehicle loads to the rut plate specimens at a frequency of 0.5 times per minute for 500 times (total time is 1000 minutes), observe the generation and development of cracks on the specimen surface, measure the crack width and length with a crack observation instrument, and calculate the crack area ratio;

[0203] ② The flexural tensile strength, cracking temperature, and fatigue life of the rutted slab specimens were tested. The specific test methods are as follows:

[0204] Flexural tensile strength test: A universal testing machine was used to apply a three-point load to the specimen, the failure load was recorded, and the flexural tensile strength was calculated. The formula for calculating the flexural tensile strength is as follows:

[0205]

[0206] In the formula: R b — Flexural tensile strength (MPa); P — Maximum load at specimen failure (N); l — Distance between two supports (mm); b — Specimen width (mm); h — Specimen height (mm).

[0207] Cracking temperature: The specimen was cooled in a low-temperature test chamber, and the surface of the specimen was observed and the temperature at which the first crack appeared was recorded.

[0208] Fatigue life test: conducted on a fatigue testing machine, a load of a certain frequency and stress level is applied to the specimen, and the number of load cycles when the specimen fails due to fatigue is recorded.

[0209] The test results are shown in Table 9.

[0210]

[0211] As shown in Table 7, the asphalt mixture of the present invention exhibits significant advantages in the dimension of emulsion storage stability, specifically:

[0212] (1) The stable days of Examples 1-8 ranged from 85 to 132 days, which is an increase of 142.9%-277.1% compared with the control samples of the traditional process, Comparative Example 1 (35 days) and Comparative Example 2 (65 days). Among them, the stable days of Example 4 can even reach 132 days, which effectively solves the problems of easy demulsification and short storage period of traditional emulsions at high temperatures.

[0213] (2) The storage stability index (0.98%-1.78%) was 68.1%-82.7% lower than that of the control sample (5.02%-6.85%), which indicates that the present invention has constructed a more stable emulsion dispersion system through micro-interface control technology, effectively suppressing the separation of oil and water phases.

[0214] (3) The fluctuation range of evaporation residue content (53.5%-64.9%) was narrowed by 4.7%-5.3% compared with the control sample (50.2%-64.8%), reflecting the synergistic effect of binder solution and stabilizer, which significantly improved the dispersion uniformity of emulsified asphalt in the emulsion system.

[0215] (3) From the perspective of rheological properties, compared with Comparative Examples 1-2, the viscosity fluctuation range of the asphalt mixtures in Examples 1-8 is smaller, and the initial viscosity is lower, which can achieve a dual improvement in construction viscosity stability and ease of operation. Among them, the viscosity fluctuation range (82.5-138.7 cP) of the asphalt mixture in Example 1 is reduced by 44.1%-53.5% compared with the viscosity fluctuation range (153.5-220.1 cP) of the asphalt mixture in Comparative Examples 1-2, and the initial viscosity (101.34-121.41 cP) is reduced by 30.8%-49.7%.

[0216]

[0217] As shown in Table 8, the spalling area of ​​the asphalt mixtures obtained in Examples 1-8 of the present invention is only 0.29%-1.23%, which is much lower than that of Comparative Example 1 (7.40%) and Comparative Example 2 (6.12%), greatly reducing the risk of spalling and improving the interfacial bonding performance between aggregates and asphalt.

[0218] The freeze-thaw splitting strength ratio of the asphalt mixtures obtained in Examples 1-8 of this invention is as high as 80.23%-87.28%, which is significantly higher than that of Comparative Example 1 (65.32%) and Comparative Example 2 (68.46%), indicating excellent freeze-thaw resistance.

[0219] The average pull-out force of the asphalt mixtures obtained in Examples 1-8 of this invention is 0.82-1.35kN, which is significantly higher than that of Comparative Example 1 (0.62kN) and Comparative Example 2 (0.67kN), and the interface is not easily fractured.

[0220] The skid resistance attenuation rate of the asphalt mixtures obtained in Examples 1-8 of this invention is 7.56%-10.23%, which is much lower than that of Comparative Example 1 (28.54%) and Comparative Example 2 (25.12%), and can significantly delay the attenuation of skid resistance performance.

[0221]

[0222] As shown in Table 9, the asphalt mixture of the present invention exhibits excellent crack resistance under sub-zero temperatures, significantly superior to asphalt mixtures obtained by conventional processes (Comparative Examples 1-2). Specifically, the crack area ratio of Examples 1-8 is 2.58%-4.12%, and the crack width is 0.13-0.29 mm, significantly lower than that of Comparative Example 1 (12.56%, 0.68 mm) and Comparative Example 2 (10.28%, 0.51 mm) with untreated aggregate. In terms of flexural tensile strength, cracking temperature, and fatigue life, the flexural tensile strength of Examples 1-8 is 6.12-8.21 MPa, the cracking temperature is as low as -23.45℃, and the fatigue life reaches 395-562 cycles, all significantly better than Comparative Example 1 (4.32 MPa, -12.23℃, 285 cycles) and Comparative Example 2 (5.23 MPa, -18.45℃, 325 cycles). The ether bonds of PEGDE form hydrogen bonds with water molecules, lowering the glass transition temperature of asphalt and improving low-temperature ductility. Meanwhile, the enhanced interfacial adhesion of STPP ensures uniform distribution of low-temperature stress, preventing localized cracking. Example 6 uses rubber-modified emulsified asphalt, whose polymer chains cross-link with asphaltene to form an elastic network, buffering low-temperature shrinkage stress and enhancing interfacial toughness. This results in a flexural tensile strength of 8.21 MPa, a cracking temperature as low as -23.45°C, and a fatigue life exceeding 562 cycles, demonstrating excellent performance.

[0223] In Comparative Example 2, a traditional cellulose stabilizer was used, which only thickens through physical winding without chemical modification. Its flexural strength was 33% lower than that of the present invention, and it could not effectively suppress low-temperature cracking. In contrast, the asphalt mixtures in Examples 1-8 of the present invention, through a three-dimensional technical path of "interfacial chemical strengthening - asphalt phase toughening - structural densification," achieved a 67% improvement in low-temperature crack resistance, an 8-10℃ extension of the low-temperature resistance limit, and a 97% increase in fatigue life, demonstrating significant advantages.

[0224] In some preferred embodiments (Example 3), the asphalt mixture exhibits the best balance between performance and cost. Specifically, in terms of technical performance, the emulsion demonstrates excellent storage stability, with a stability period of up to 119 days, which is superior to comparative examples 1-2, providing reliable assurance for construction. It also exhibits strong adhesion between aggregates and asphalt, with a spalling area ratio as low as 0.34%, a high freeze-thaw splitting strength ratio, and stable skid resistance. Furthermore, it demonstrates excellent low-temperature crack resistance, with a crack area ratio of 2.85%, making it adaptable to low-temperature environments. In terms of economic cost, compared to Example 4 with a higher solids content, its 60% emulsified asphalt solids content makes the raw material cost more advantageous. Moreover, the 2.0% PEGDE content and the 40-minute pretreatment of aggregates with 12% STPP concentration may reduce the amount of additives used, thus lowering costs. Example 3 meets road performance requirements while controlling costs, offering high cost-effectiveness and significant potential for widespread adoption.

[0225] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. An asphalt mixture, characterized in that, Its raw materials include the following components: 9-10 parts emulsified asphalt, modified aggregate, and stabilizer; The modified aggregate comprises 75-85 parts of aggregate and a binder solution; the aggregate comprises 40-50 parts of coarse aggregate with a particle size of 4.75mm-9.5mm and 35-45 parts of fine aggregate with a particle size of 0.075mm-2.36mm; the binder in the binder solution comprises anionic surfactant, and the amount of binder is 0.3%-0.5%, where the percentage is the mass percentage of the binder to the aggregate; The stabilizer includes a polyether-type epoxy stabilizer, and the amount of the stabilizer is 1.0%-2.5%, where the percentage is the mass percentage of the stabilizer to the emulsified asphalt.

2. The asphalt mixture as described in claim 1, characterized in that, The stabilizer and the binder satisfy one or more of the following conditions: a. The polyether-type epoxy stabilizer includes polyethylene glycol diglycidyl ether; b. The stabilizer also includes sodium silicate; c. The anionic surfactant includes sodium tripolyphosphate and / or calcium lignosulfonate; d. The adhesive solution is an aqueous adhesive solution; e. The concentration of the adhesive solution is 5%-15%, preferably 8%-14% or 5%-10%, for example 10% or 12%, where the concentration is the mass percentage of the adhesive in the adhesive solution; f. The amount of the adhesive used is 0.35%-0.45%, for example, 0.40%; g. The amount of the stabilizer is 1.5%-2.5%, for example, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3% or 2.4%.

3. The asphalt mixture as described in claim 1, characterized in that, The modified aggregate satisfies one or more of the following conditions ak: a. The amount of coarse aggregate used is 45-50 parts; b. The amount of fine aggregate used is 35-45 parts; c. The coarse aggregate includes basalt; d. The fine aggregate includes manufactured sand; e. The aggregate has a continuous gradation, which is as follows: 95%-100% passing rate for a 9.5mm sieve (e.g., 98.7%); 75%-90% passing rate for a 4.75mm sieve (e.g., 83.8%); 45%-70% passing rate for a 2.36mm sieve (e.g., 58.7%); 25%-50% passing rate for a 1.18mm sieve (e.g., 38.4%); 15%-35% passing rate for a 0.6mm sieve (e.g., 25.2%); 8%-20% passing rate for a 0.3mm sieve (e.g., 14.9%); 3%-12% passing rate for a 0.15mm sieve (e.g., 8.5%); and 1%-8% passing rate for a 0.075mm sieve (e.g., 5.3%). Preferably, the continuous gradation of the aggregate is as follows: 98.7% passing rate for 9.5mm sieve openings, 83.8% passing rate for 4.75mm sieve openings, 58.7% passing rate for 2.36mm sieve openings, 38.4% passing rate for 1.18mm sieve openings, 25.2% passing rate for 0.6mm sieve openings, 14.9% passing rate for 0.3mm sieve openings, 8.5% passing rate for 0.15mm sieve openings, and 5.3% passing rate for 0.075mm sieve openings. f. The absorbance of the modified aggregate is 0.10-0.20, for example, 0.11, 0.12, 0.13, 0.14, 0.17 or 0.18; g. The spalling mass loss rate of the modified aggregate is 3%-6.5%, for example, 3.1%, 3.2%, 3.4%, 4.7%, 5.0% or 6.2%; h. The zeta potential of the coarse aggregate in the modified aggregate is 19-30 mV, for example, 19.1 mV, 20.7 mV, 23.5 mV, 24.8 mV, 26.2 mV, 27.8 mV or 28.3 mV; i. The Marshall stability of the coarse aggregate in the modified aggregate is 13-17 kN, for example, 13.30 kN, 13.75 kN, 14.52 kN, 14.65 kN, 15.23 kN, 15.89 kN or 16.48 kN; j. The Zeta potential of the fine aggregate in the modified aggregate is 14-21 mV, for example, 14.5 mV, 16.8 mV, 17.6 mV, 18.3 mV, 19.2 mV, 19.8 mV or 20.1 mV; k. The bulk density of the fine aggregate in the modified aggregate is 2.5-2.6 g / cm³. 3 For example, 2.530 g / cm³ 3 2.554 g / cm 3 2.558 g / cm 3 2.564 g / cm 3 2.572 g / cm 3 2.575 g / cm 3 2.578 g / cm 3 Or 2.587 g / cm 3 .

4. The asphalt mixture as described in claim 1, characterized in that, The stabilizer satisfies one or more of the following conditions a: a. The epoxy value of the stabilizer is 0.5-0.7 eq / 100g, preferably 0.58-0.64 eq / 100g; b. The epoxy equivalent of the stabilizer is 150-170 g / eq, preferably 152-170 g / eq; c. The hydrolyzable chlorine content of the stabilizer is not higher than 0.03 eq / 100g, preferably not higher than 0.02 eq / 100g; d. The inorganic chlorine content of the stabilizer is not higher than 0.005 eq / 100g, preferably not higher than 0.003 eq / 100g; e. The purity of the stabilizer is not less than 85%, preferably not less than 90%.

5. The asphalt mixture as described in claim 1, characterized in that, The adhesive satisfies one or more of the following conditions: a. The phosphorus content in the binder is 55%-60%, preferably 57%-58%, where the percentage refers to the mass percentage of P2O5 in the binder; b. The pH value of the adhesive is 8.0-10.0, preferably 9.0-10.0; c. The water-insoluble content of the adhesive is less than 0.2%, preferably less than 0.1%; d. The purity of the adhesive is not less than 90%, preferably not less than 95%.

6. The asphalt mixture as described in claim 1, characterized in that, The stabilizer is polyethylene glycol diglycidyl ether, and the binder is sodium tripolyphosphate; Preferably, the polyethylene glycol diglycidyl ether meets the following conditions: epoxy value of 0.58-0.64 eq / 100g; epoxy equivalent of 152-170 g / eq; hydrolyzable chlorine content of not more than 0.02 eq / 100g; inorganic chlorine content of not more than 0.003 eq / 100g; and purity of not less than 90%. Preferably, the sodium tripolyphosphate meets the following conditions: phosphorus content of 57%-58%, where the percentage refers to the mass percentage of P2O5 in the binder; pH value of 9.0-10.0; water-insoluble content of less than 0.1%; and purity of not less than 95%.

7. A method for preparing an asphalt mixture as described in any one of claims 1-6, characterized in that, It includes the following steps: The modified aggregate, the emulsified asphalt, the stabilizer, and the solvent are mixed.

8. The method for preparing asphalt mixture as described in claim 7, characterized in that, The method for preparing the modified aggregate includes the following steps: S1. Preheat the aggregate to obtain preheated aggregate; S2. Mix the preheated aggregate and the binder solution, and then dry them; In step S1, the preheating temperature is preferably 100-130℃, for example, 120℃; In step S1, the preheating time is preferably 2-4 hours, for example, 3 hours; In step S2, the mixing temperature is preferably 40-60°C, for example, 50°C; In step S2, the mixing time is preferably 15-50 min, more preferably 20-50 min, for example 30 min.

9. The method for preparing asphalt mixture according to claim 7, characterized in that, The discharge temperature of the asphalt mixture is 75-90℃, for example, 85℃.

10. The method for preparing asphalt mixture according to claim 7, characterized in that, The mixing process includes the following steps: The first mixture and the stabilizer are mixed to obtain a second mixture, and the second mixture is mixed with the solvent; The first mixture comprises the emulsified asphalt and the modified aggregate; the preparation method of the first mixture preferably includes the following steps: spraying the emulsified asphalt onto the surface of the modified aggregate while stirring; The solvent is, for example, water.

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