Preparation method of rock asphalt composite modified asphalt mixture and related mixture

Abstract

The invention discloses a preparation method of a rock asphalt composite modified asphalt mixture and a related mixture, and the method comprises the following steps: mixing rock asphalt powder of a target specification and aromatic hydrocarbon oil according to a preset proportion, and shearing and stirring according to an attenuation sine function under a temperature control condition through temperature control high shear dispersion equipment to obtain a rock asphalt mother solution; heating the matrix asphalt to a preset temperature and keeping for a preset time so as to carry out melting treatment; high-shear mixing equipment is utilized, various raw materials containing the treated matrix asphalt and the rock asphalt mother liquor in a preset proportion are added into a mixing kettle, the temperature and shear stress are controlled through a target model, and modified asphalt is obtained; the preparation method comprises the following steps: sequentially adding aggregates with various particle sizes, recycled asphalt, modified asphalt and mineral powder in a preset ratio into forced stirring equipment, and carrying out dry mixing and wet mixing according to a preset time sequence under a temperature control condition, so as to prepare the asphalt mixture. According to the scheme, the compatibility among the rock asphalt, the matrix asphalt and the modifier can be improved.

Description

Technical Field

[0001] The present application relates to the field of inorganic ingredient mixtures, and in particular to a preparation method of a rock asphalt composite modified asphalt mixture and related mixtures. Background Art

[0002] Asphalt mixture is one of the most commonly used materials in road paving, and its performance directly affects the service life, driving comfort and safety of the road. At present, the preparation of asphalt mixture usually adopts the following method: mixing base asphalt with modifiers, additives and other materials to prepare modified asphalt, and then mixing the modified asphalt with mineral materials, fillers and the like to prepare asphalt mixture. This traditional asphalt mixture preparation method has achieved certain results in practical applications and can improve the durability, rutting resistance and water damage resistance of asphalt pavement to a certain extent. However, with the continuous increase in traffic loads and increasingly complex climatic conditions, the existing technology still faces many challenges and it is difficult to meet the increasingly stringent road performance requirements.

[0003] The existing asphalt mixture preparation technology has the following major problems: In the prior art, the interface bonding strength between modified asphalt and mineral materials is insufficient, resulting in the overall performance of the asphalt mixture being less than ideal. This is mainly because the surface characteristics of modified asphalt are somewhat different from the surface of mineral materials, making it difficult to form a stable physical and chemical bond. Since rock asphalt contains more inorganic minerals and polymer compounds, its chemical composition and structure are significantly different from those of matrix asphalt. This makes it difficult for the two to form a uniform and stable system during the mixing process. In the prior art, modifiers are usually directly added to matrix asphalt for mixing. However, due to the large differences in physical properties such as viscosity, density and surface tension between modifiers (such as polymer materials such as SBS and SBR) and matrix asphalt, it is difficult to achieve uniform dispersion in a short time.

[0004] Therefore, there is an urgent need for a technical solution that can improve the compatibility between rock asphalt, base asphalt and modifiers. Summary of the invention

[0005] In order to solve the deficiencies of the prior art, the present application provides a method for preparing a rock asphalt composite modified asphalt mixture and related mixtures. The present application solves the technical problems of the prior art such as poor compatibility between rock asphalt, base asphalt and modifier.

[0006] The embodiment of the present application provides a method for preparing a rock asphalt composite modified asphalt mixture, comprising: mixing rock asphalt powder of a target specification with aromatic oil in a preset ratio, shearing and stirring according to a decaying sine function under temperature control conditions through a temperature-controlled high-shear dispersion device to obtain a rock asphalt mother liquor; heating the base asphalt to a predetermined temperature and maintaining it for a preset time for melting treatment; using a high-shear mixing device, adding a plurality of raw materials including treated base asphalt and rock asphalt mother liquor in preset ratios into a mixing kettle, and controlling the temperature and shear stress through a target model to obtain modified asphalt; and sequentially putting a plurality of particle size aggregates, recycled asphalt, modified asphalt and mineral powder in predetermined ratios into a forced mixing device, and performing dry mixing and wet mixing according to a preset sequence under temperature control conditions to prepare an asphalt mixture.

[0007] In a possible implementation, the target specification of rock asphalt powder and aromatic oil are mixed in a preset ratio, sheared and stirred according to a decaying sine function under temperature control conditions by a temperature-controlled high-shear dispersion device, and stored at a constant temperature after completion, including: selecting rock asphalt powder with a particle size not greater than 0.075 mm and a purity not less than 99%, and aromatic oil with a cycloalkyl content not less than 55% and a flash point not less than 220°C, mixing them in a mass ratio of 1:2 to obtain a mixture; placing the mixture in a high-shear dispersion device with temperature control and variable frequency stirring functions, controlling the temperature within the range of 175-185°C, using a decaying sine function to control the shear rate, and continuously stirring for 1 hour at an initial shear rate of 1500s^-1; after the stirring is completed, the obtained rock asphalt mother liquor is transferred to an insulation device maintained at a temperature of 160°C.

[0008] In one possible implementation, the base asphalt is heated to a predetermined temperature and maintained for a preset time for melting treatment, including: selecting No. 70 base asphalt with a softening point of 46-50°C and a needle penetration of 60-80mm, placing it in a heating device, raising its temperature to 160°C and maintaining this temperature for 30 minutes to ensure that the base asphalt is fully melted.

[0009] In a possible implementation, a high shear mixing device is used to add a preset proportion of multiple raw materials including treated base asphalt and rock asphalt mother liquor to a mixing kettle, and the temperature and shear stress are controlled by a target model to obtain modified asphalt, including: using a high shear mixing device including temperature control and shear stress control functions, the treated base asphalt, rock asphalt mother liquor, modifier and aromatic oil are weighed in a predetermined proportion and placed in a mixing kettle in turn, and the total mass is controlled within a set value range; the temperature of the mixing kettle is controlled to follow a target temperature control function relationship, wherein the target temperature control function includes an initial temperature, a temperature change amplitude, a heating rate and a periodic fluctuation parameter; the shear stress of the mixing kettle is adjusted to follow a target shear function relationship, wherein the target shear function includes a reference shear stress, a fluctuation amplitude and a periodic parameter, and intermittent shearing is achieved through a periodic switching function; the mixing operation is continued within a predetermined time, and the modified asphalt is transferred to a constant temperature container after the operation is completed.

[0010] In a possible implementation, various aggregate sizes, recycled asphalt, modified asphalt and mineral powder in predetermined proportions are sequentially put into a forced mixing device, and dry-mixed and wet-mixed according to a preset sequence under temperature-controlled conditions to prepare an asphalt mixture, including: weighing modified asphalt, mineral powder, various aggregate sizes and recycled asphalt in predetermined proportions; putting the weighed various aggregate sizes and recycled asphalt into a forced mixing device, and dry-mixing them at a preset speed for a predetermined time; adding modified asphalt to the dry-mixed mixture, and after wet-mixing for a predetermined time, continuing to stir the composite mineral powder, and controlling the temperature of the entire process within a preset range to prepare the asphalt mixture.

[0011] In one possible implementation, the shear rate is controlled by using a decaying sine function, including: γ(t) = γ0·e -kt sin(ωt), where γ(t) is the shear rate at time t, γ0 is the initial shear rate, ranging from 1000 to 2000 s^-1, k is the attenuation coefficient, ranging from 0.01 to 0.04 s^-1, and ω is the angular frequency, ranging from 0.15 to 0.6 rad / s.

[0012] In one possible implementation, the target temperature control function relationship is made to follow: T(t) = T0 + ΔT·(1-e -αt )·(1+βsin(θt)), where T(t) represents the temperature at time t, T0 represents the initial temperature, which is 140°C, ΔT represents the maximum temperature change, which is 40°C, α represents the heating rate coefficient, which is in the range of 0.005-0.009s^-1, β represents the temperature fluctuation coefficient, which is in the range of 0.1-0.2, and θ represents the temperature fluctuation angular frequency, which is in the range of 0.01-0.05rad / s.

[0013] In a possible implementation, in which it is made to follow the target shear function relationship, including: τ(t)=τ0·(1+λsin(φt))·H(sin(ψτ)), wherein τ(t) represents the shear stress at time t, τ0 represents the basic shear stress, and its value range is 1000-1750Pa, λ represents the stress fluctuation coefficient, and its value range is 0.2-0.4, φ represents the stress fluctuation angular frequency, and its value range is 0.5-0.7rad / s, ψ represents the pulse frequency, and its value range is 0.1-0.2rad / s, H() represents the step function, and when x≥0, H(x)=1, otherwise H(x)=0.

[0014] The embodiment of the present application also provides a rock asphalt composite modified asphalt mixture prepared by the method described in any of the above embodiments, including: 66.43 units of mass of No. 70 base asphalt, 18.2 units of mass of rock asphalt mother liquor, 2.73 units of mass of 6302 modifier, 3.64 units of mass of aromatic oil, 9 units of mass of mineral powder, 10 units of mass of aggregate with a particle size of 0-3mm, 3 units of mass of aggregate with a particle size of 3-6mm, 30 units of mass of aggregate with a particle size of 6-11mm, 28 units of mass of aggregate with a particle size of 11-16mm, and 20 units of mass of recycled asphalt.

[0015] In the preparation method of a rock asphalt composite modified asphalt mixture and the related mixture provided above, the embodiment of the present application can improve the compatibility between rock asphalt, base asphalt and modifier through rock asphalt mother liquor pretreatment and multi-stage temperature control compatibilization technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 A schematic flow chart of a method for preparing a rock asphalt composite modified asphalt mixture provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure unless otherwise specifically stated.

[0019] Those skilled in the art can understand that the terms "first", "second" and the like in the embodiments of the present disclosure are only used to distinguish different steps, devices or modules, etc., and neither represent any specific technical meaning nor represent the necessary logical order between them. It should also be understood that in the embodiments of the present disclosure, "multiple" can refer to two or more, and "at least one" can refer to one, two or more. It should also be understood that for any component, data or structure mentioned in the embodiments of the present disclosure, in the absence of explicit limitation or contrary revelation given in the context, it can generally be understood as one or more. In addition, the term "and / or" in the present disclosure is only a description of the association relationship of the associated objects, indicating that there can be three relationships, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present disclosure generally indicates that the associated objects before and after are an "or" relationship. It should also be understood that the description of each embodiment in the present disclosure emphasizes the differences between the embodiments, and the same or similar parts can refer to each other. For the sake of brevity, they will not be repeated one by one.

[0020] At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present disclosure and its application or use. The techniques, methods and devices known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and devices should be considered part of the specification. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0022] Figure 1A schematic flow chart of a method for preparing a rock asphalt composite modified asphalt mixture provided in an embodiment of the present application. At present, the preparation of asphalt mixtures generally adopts the following method: base asphalt is mixed with modifiers, additives and other materials to prepare modified asphalt, and then the modified asphalt is mixed with mineral materials, fillers and the like to prepare asphalt mixtures. This method has the following problems: the modified asphalt has poor compatibility with mineral materials, resulting in less than ideal performance of the asphalt mixture. Since rock asphalt contains more inorganic minerals and polymer compounds, it has poor compatibility with base asphalt, resulting in phase separation after mixing, affecting the uniformity and stability of the final asphalt mixture. In the prior art, the modifier is usually added directly to the base asphalt. Due to the large difference in viscosity between the modifier and the base asphalt, it is difficult to achieve uniform dispersion in a short time, resulting in unstable modification effect, affecting the overall performance of the asphalt mixture.

[0023] In order to solve the above problems, the embodiment of the present application adopts rock asphalt mother liquor pretreatment technology, and combines it with multi-stage temperature control compatibilization technology for mixing, which can significantly improve the compatibility between rock asphalt, matrix asphalt and modifier, reduce phase separation phenomenon, and improve the uniformity of asphalt mixture.

[0024] like Figure 1 As shown, at step S101, the rock asphalt powder of the target specification is mixed with aromatic oil in a preset ratio, and sheared and stirred according to a decaying sine function under temperature control conditions by a temperature-controlled high-shear dispersion device to obtain a rock asphalt mother liquor. Rock asphalt is a naturally occurring solid or semi-solid asphalt with unique physical and chemical properties. Crushing it into a powder form with a specific particle size can increase its contact area with other materials, thereby improving the efficiency of subsequent processing. Aromatic oil, as an additive, can improve the fluidity and dispersibility of rock asphalt.

[0025] Specifically, the method comprises: selecting rock asphalt powder with a particle size not greater than 0.075 mm and a purity not less than 99%, and aromatic oil with a cycloalkyl content not less than 55% and a flash point not less than 220°C, mixing them in a mass ratio of 1:2 to obtain a mixture; placing the mixture in a high shear dispersion device with temperature control and variable frequency stirring functions, controlling the temperature within the range of 175-185°C, using a decaying sinusoidal function to control the shear rate, and continuously stirring for 1 hour at an initial shear rate of 1500s^-1; after the stirring is completed, transferring the obtained rock asphalt mother liquor to an insulation device maintained at a temperature of 160°C.

[0026] The shear rate is controlled by a decaying sine function, including: γ(t) = γ0·e -kt·sin(ωt), where γ(t) represents the shear rate at time t, γ0 represents the initial shear rate, and the range includes 1000-2000s^-1, k represents the attenuation coefficient, and the range includes 0.01-0.04s^-1, and ω represents the angular frequency, and the range includes 0.15-0.6rad / s. The principle of rock asphalt mother liquor pretreatment technology is based on colloid chemistry and rheology theory. By mixing rock asphalt powder with aromatic oil and stirring it under high temperature conditions, the inorganic minerals and polymer compounds in the rock asphalt can be fully dispersed. The shear rate gradient control technology is adopted, in which the exponential decay term exp(-k*t) ensures that the shear strength gradually decreases over time to avoid structural damage caused by excessive shearing; the sinusoidal term sin(ω*t) provides periodic shear changes, which helps to break the local equilibrium and promote the full mixing and dispersion of the material. By controlling the γ0, k and ω parameters, the stirring process can be optimized for different types of rock asphalt and aromatic oil to achieve the best dispersion effect.

[0027] In one embodiment, the asphalt mother liquor is first pretreated. High-purity asphalt powder (particle size ≤ 0.075 mm, purity ≥ 99%) and aromatic oil (cycloalkyl content ≥ 55%, flash point ≥ 220° C.) are selected. The asphalt powder and aromatic oil are mixed in a mass ratio of 1:2, with a total mass of 20 kg as an example.

[0028] Use a high shear disperser with precise temperature control and variable frequency stirring function (such as IKA Magic LAB model, maximum speed 24000rpm). Pour the mixture into the reactor and set the temperature to 180±5℃. Start the agitator, set the initial shear rate γ0 to 1500s^(-1), the attenuation coefficient k to 0.03s^(-1), and the angular frequency ω to 0.3rad / s.

[0029] The shear rate is controlled according to the formula γ(t)=γ0*exp(-k*t)*sin(ω*t). For example, at t=10min, the shear rate is about: γ(600)=1500*exp(-0.03*600)*sin(0.3*600)≈228.4s^(-1). Stir continuously for 1 hour, during which the temperature and stirring status are checked every 15 minutes to ensure that the temperature is stable within the range of 175-185℃. After stirring, transfer the rock asphalt mother liquor to an insulated container and keep the temperature at about 160℃ for standby use.

[0030] It should be understood that the embodiments of the present application use shear stirring according to a decaying sinusoidal function. This unique stirring method simulates the common periodic changes in nature and can provide dynamic and changing shear forces during the material mixing process. The decaying sinusoidal function means that the intensity of the shear force will show periodic changes over time, and the overall trend is gradually weakening. This stirring method can provide a strong shearing effect in the early stage and quickly break the agglomeration state of the rock asphalt powder, while the weaker shearing in the later stage is conducive to the stability of the system. In this way, while fully dispersing the rock asphalt, the negative effects that may be caused by excessive shearing, such as damage to the material structure or degradation of performance, can be avoided.

[0031] At step S102, the matrix asphalt is heated to a predetermined temperature and kept for a preset time to be melt-treated. The matrix asphalt is the basic component of the whole mixture, and its property directly affects the multiple performance indicators of the final product. The matrix asphalt is heated to a predetermined temperature and kept for a preset time, and this process is called melt-treated. It should be understood that asphalt is a complex hydrocarbon mixture, and its physical state and rheological properties are closely related to temperature. By controlling the heating temperature and duration, the precise regulation and control of the molecular structure and fluidity of the matrix asphalt can be achieved.

[0032] The process includes: selecting No. 70 base asphalt with a softening point of 46-50°C and a needle penetration of 60-80mm, placing it in a heating device, raising its temperature to 160°C and maintaining the temperature for 30 minutes to ensure that the base asphalt is fully melted.

[0033] Specifically, a No. 70 base asphalt with a softening point of 46-50°C and a needle penetration of 60-80mm is selected. The base asphalt is heated to 160°C and maintained for 30 minutes to ensure complete melting. A rotary film oven (such as the FD series) is used for short-term aging treatment to simulate the aging conditions in the actual production process. The temperature is set to 163°C, the rotation speed is 15±1r / min, and the treatment time is 85±5min.

[0034] At step S103, a plurality of raw materials including the treated matrix asphalt and the rock asphalt mother liquor in a preset ratio are added to a mixing kettle using a high shear mixing device, and the temperature and shear stress are controlled by the target model to obtain modified asphalt. In this step, the treated matrix asphalt is mixed with the previously prepared rock asphalt mother liquor in a preset ratio. The determination of this ratio may take into account multiple factors, including but not limited to the desired final performance index, the compatibility of each component, the economy, etc.

[0035] Specifically, the method includes: using a high shear mixing device with temperature control and shear stress control functions, weighing the treated base asphalt, rock asphalt mother liquor, modifier and aromatic oil in a predetermined proportion in turn and placing them in a mixing kettle, and controlling the total mass within the set value range; controlling the temperature of the mixing kettle so that it follows the target temperature control function relationship, wherein the target temperature control function includes the initial temperature, the temperature change amplitude, the heating rate and the periodic fluctuation parameter; adjusting the shear stress of the mixing kettle so that it follows the target shear function relationship, wherein the target shear function includes the reference shear stress, the fluctuation amplitude and the periodic parameter, and intermittent shearing is achieved through a periodic switching function; continuing the mixing operation within a predetermined time, and transferring the modified asphalt to a constant temperature container after the operation is completed.

[0036] Among them, it follows the target temperature control function relationship, including: T(t) = T0 + ΔT·(1-e -αt )·(1+βsin(θt)), where T(t) represents the temperature at time t, T0 represents the initial temperature, which is 140°C, ΔT represents the maximum temperature change, which is 40°C, α represents the heating rate coefficient, which is in the range of 0.005-0.009s^-1, β represents the temperature fluctuation coefficient, which is in the range of 0.1-0.2, and θ represents the temperature fluctuation angular frequency, which is in the range of 0.01-0.05rad / s.

[0037] Among them, it is made to follow the target shear function relationship, including: τ(t)=τ0·(1+λsin(φt))·H(sin(ψt)), wherein τ(t) represents the shear stress at time t, τ0 represents the basic shear stress, and its value range is 1000-1750Pa, λ represents the stress fluctuation coefficient, and its value range is 0.2-0.4, φ represents the stress fluctuation angular frequency, and its value range is 0.5-0.7rad / s, ψ represents the pulse frequency, and its value range is 0.1-0.2rad / s, and H() represents the step function. When x≥0, H(x)=1, otherwise H(x)=0.

[0038] Multi-stage temperature control compatibilization technology combines the principles of thermodynamics and rheology. In the temperature control strategy, the exponential term (1-exp(-α*t)) achieves a smooth temperature rise, avoiding local overheating that may be caused by sudden temperature rise; the sinusoidal term (1+β*sin(θ*t)) introduces temperature fluctuations, which helps to break the thermal balance of the system and promote the full mixing of the components. Pulse shear technology utilizes the characteristics of non-Newtonian fluids. Sinusoidal term It provides periodic shear strength changes, which helps to destroy the internal structure of the material and promote mixing; the step function H (sin (ψ * t)) introduces intermittent shearing, giving the material a certain recovery time to avoid performance degradation caused by excessive shearing. By controlling the changes in temperature and shear stress, the full compatibility of each component can be achieved to form a stable composite system.

[0040] In one implementation scenario, in order to perform multi-stage temperature-controlled compatibilization mixing, a high shear mixing device (such as the Dispax-Reactor series) with precise temperature control and shear stress control functions is used. The treated base asphalt (73%, 14.6 kg), pretreated rock asphalt mother liquor (20%, 4 kg), 6302 modifier (3%, 0.6 kg) and additional aromatic oil (4%, 0.8 kg) are added to the mixing kettle in proportion, with a total mass of 20 kg.

[0041] The temperature control strategy follows the formula: T(t) = T0 + ΔT*(1-exp(-α*t))*(1+β*sin(θ*t)), where T0 = 140°C, ΔT = 40°C, α = 0.007s^(-1), β = 0.15, θ = 0.03rad / s. For example, at t = 30min, the temperature is approximately: T(1800) = 140 + 40*(1-exp(-0.007*1800))*(1+0.15*sin(0.03*1800)) ≈ 175.2°C

[0042] The shear stress control strategy follows the formula: Among them, τ0=1500Pa, λ=0.3, ψ=0.15rad / s. For example, at t=5min, the shear stress is about: τ(300)=1500*(1+0.3*sin(0.75*300))*H(sin(0.15*300))≈1182Pa

[0043] The mixing process lasted for 2 hours, during which the temperature and shear stress data were recorded every 15 minutes to ensure the normal operation of the equipment. After the mixing was completed, the modified asphalt was transferred to an insulated container and kept at a temperature of about 165°C for standby use.

[0044] At step S104, various aggregates of predetermined particle sizes, recycled asphalt, modified asphalt and mineral powder are sequentially put into a forced mixing device, and dry mixing and wet mixing are performed according to a preset time sequence under temperature control conditions to prepare an asphalt mixture. This step combines the results of the previous steps and mixes various raw materials according to the designed ratio and sequence. It should be understood that asphalt mixture is a complex multiphase system, including solid aggregates, fillers and liquid asphalt. The proportion and mixing order of each component directly affect the working performance, mechanical properties and durability of the mixture. The use of aggregates of various particle sizes is intended to form a good skeleton structure and provide strength and stability of the mixture. The addition of recycled asphalt is not only environmentally friendly, but also can improve certain properties of the mixture. Modified asphalt acts as a binder to tightly bind the components and give the mixture good road performance. The addition of mineral powder can fill the pores between aggregates and enhance the density and water resistance of the mixture.

[0045] Specifically, the method includes: weighing a predetermined proportion of modified asphalt, mineral powder, aggregates of various particle sizes and recycled asphalt; placing the weighed aggregates of various particle sizes and recycled asphalt into a forced mixing device, and dry mixing them at a preset speed for a predetermined time; adding modified asphalt to the dry-mixed mixture, and continuing to stir the composite mineral powder after wet mixing for a predetermined time, and controlling the temperature of the entire process within a preset range to prepare an asphalt mixture.

[0046] Furthermore, according to the target mix ratio, the following materials are prepared: modified asphalt (5.8%, 1.16kg), mineral powder (9%, 1.8kg), 0-3mm aggregate (10%, 2kg), 3-6mm aggregate (3%, 0.6kg), 6-11mm aggregate (30%, 6kg), 11-16mm aggregate (28%, 5.6kg), and recycled asphalt 10 (20%, 4kg).

[0047] Use a forced mixer (such as the HJW series) for mixing. First, add aggregates of various specifications and recycled asphalt to the mixer and dry mix for 30 seconds. Then add modified asphalt and wet mix for 90 seconds. Finally, add mineral powder and continue mixing for 60 seconds. During the whole process, keep the mixing temperature at 165±5℃.

[0048] After the mixing is completed, the Marshall specimens are prepared immediately. Using a Marshall compactor (such as SLX-II), each specimen is compacted 75 times on both sides at a temperature of 165°C. Five specimens are prepared and numbered 1-5. In one embodiment, the experimental data are shown in Table 1 below:

[0049] Table 1 Density of asphalt mixture (surface dry method or water weight method) and Marshall test record

[0050]

[0051] In addition, the following tests can be performed in accordance with JTG E20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering":

[0052] Bulk density test: Use the water weight method to determine the bulk density of the specimen. Soak the specimen in water at 25±1℃ for 30 minutes, weigh the mass in the water, and then quickly wipe off the surface moisture and weigh the surface dry mass. The calculation formula is as follows: ρf=A / (BC), where ρf is the bulk density of the specimen (g / cm3), A is the mass of the specimen in the air (g), B is the surface dry mass of the specimen (g), and C is the mass of the specimen in water (g).

[0053] Calculation of void fraction: Based on the measured volume density and the theoretical maximum density (2.554 g / cm3), calculate the void fraction: VV = (1-ρf / ρt) * 100%, where VV is the void fraction (%), ρf is the volume density of the specimen (g / cm3), and ρt is the theoretical maximum density (g / cm3).

[0054] Marshall stability and flow value test: Use a Marshall tester (such as CSI-1) to heat the specimen to 60±1℃ and keep it warm for 30-40 minutes. Then place the specimen in the test fixture and load it at a speed of 50±5mm / min until it fails. Record the maximum load (stability) and the corresponding deformation (flow value).

[0055] According to the recorded data, the average values ​​are calculated. The average volume density is 2.458g / cm3, the average porosity is 3.8%, the average Marshall stability is 12.76kN, and the average flow value is 2.6mm. These data show that the prepared asphalt mixture has achieved the expected performance requirements.

[0056] In summary, the present application embodiment can significantly improve the compatibility between rock asphalt, matrix asphalt and modifier, reduce phase separation phenomenon and improve the uniformity of asphalt mixture by rock asphalt mother liquor pretreatment and multi-stage temperature control compatibilization technology. This will be directly reflected in the microstructure of asphalt mixture, and a more uniform phase structure can be observed by scanning electron microscope (SEM). The improved mixing method can promote the formation of a more stable network structure between the components and improve the high temperature stability of asphalt mixture. This can be verified by dynamic shear rheometer (DSR) test, and it is expected that the high temperature performance grade of composite modified asphalt can be improved by 1-2 grades. Through the optimized mixing process, the performance of rock asphalt and modifier can be better utilized, and the low temperature flexibility of asphalt mixture can be improved. This can be verified by bending beam rheometer (BBR) test, and it is expected that the low temperature crack resistance of composite modified asphalt can be improved by 20-30%. More uniform mixing can reduce the interface weakness between asphalt and mineral material and improve the water stability of asphalt mixture. This can be verified by immersion Marshall test, and it is expected that the residual stability of immersion can be improved by 5-10 percentage points.

[0057] Furthermore, an embodiment of the present application also provides a rock asphalt composite modified asphalt mixture prepared by the method described in any of the above embodiments, including: 66.43 units of mass of No. 70 base asphalt, 18.2 units of mass of rock asphalt mother liquor, 2.73 units of mass of 6302 modifier, 3.64 units of mass of aromatic oil, 9 units of mass of mineral powder, 10 units of mass of aggregate with particle size of 0-3mm, 3 units of mass of aggregate with particle size of 3-6mm, 30 units of mass of aggregate with particle size of 6-11mm, 28 units of mass of aggregate with particle size of 11-16mm and 20 units of mass of recycled asphalt.

[0058] Furthermore, an embodiment of the present application also provides a device for preparing a rock asphalt composite modified asphalt mixture, comprising: a processor, a memory, and a system bus; the processor and the memory are connected via the system bus; the memory is used to store one or more programs, and the one or more programs include instructions, which, when executed by the processor, enable the processor to execute any of the above methods.

[0059] Furthermore, an embodiment of the present application also provides a computer program product, which, when executed on a terminal device, enables the terminal device to execute any one of the above-mentioned processing methods.

[0060] It can be known from the description of the above implementation mode that those skilled in the art can clearly understand that all or part of the steps in the above-mentioned embodiment method can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product can be stored in a storage medium such as ROM / RAM, a disk, an optical disk, etc., including several instructions for enabling a computer device (which can be a personal computer, a server, or a network communication device such as a media gateway, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0061] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0062] It should also be noted that, in the embodiments of the present application, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements that are not clearly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements limited by the statement "comprise one..." do not exclude the presence of other identical elements in the process, method, article or equipment including the elements.

[0063] The above description of the disclosed embodiments enables professionals and technicians in the field to implement or use the present application. Various modifications to these embodiments will be apparent to professionals and technicians in the field, and the general principles defined in the embodiments of the present application can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown in the embodiments of the present application, but will conform to the widest range consistent with the principles and novel features disclosed in the embodiments of the present application.

Claims

1. A method for preparing a rock asphalt composite modified asphalt mixture, characterized in that: include: The rock asphalt powder of target specifications is mixed with aromatic oil in a preset ratio, and sheared and stirred according to a decaying sine function under temperature control conditions by a temperature-controlled high shear dispersion device to obtain a rock asphalt mother liquor; Heating the base asphalt to a predetermined temperature and maintaining it for a predetermined time to perform a melting process; Using a high shear mixing device, a plurality of raw materials including treated base asphalt and rock asphalt mother liquor in a preset ratio are added to a mixing kettle, and the temperature and shear stress are controlled by a target model to obtain modified asphalt; Aggregates of various particle sizes, recycled asphalt, modified asphalt and mineral powder in predetermined proportions are sequentially put into the forced mixing equipment, and dry and wet mixed according to a preset sequence under temperature control conditions to prepare asphalt mixture.

2. The preparation method according to claim 1, characterized in that: in, The target rock asphalt powder and aromatic oil are mixed in a preset ratio, sheared and stirred according to a decaying sine function under temperature-controlled conditions by a temperature-controlled high-shear dispersion device, and stored at a constant temperature after completion, including: Select rock asphalt powder with a particle size of not more than 0.075 mm and a purity of not less than 99%, and aromatic oil with a cycloalkyl content of not less than 55% and a flash point of not less than 220° C., mix them in a mass ratio of 1:2 to obtain a mixture; The mixture is placed in a high shear dispersion device with temperature control and variable frequency stirring functions, the temperature is controlled within the range of 175-185°C, the shear rate is controlled by a decaying sine function, and stirring is continued for 1 hour at an initial shear rate of 1500 s^-1; After the stirring is completed, the obtained rock asphalt mother liquor is transferred to a heat preservation device maintained at 160°C.

3. The preparation method according to claim 1, characterized in that: in, The base asphalt is heated to a predetermined temperature and maintained for a predetermined time to perform a melt process, including: A No. 70 base asphalt with a softening point of 46-50°C and a needle penetration of 60-80 mm is selected and placed in a heating device to raise its temperature to 160°C and maintain this temperature for 30 minutes to ensure that the base asphalt is fully melted.

4. The preparation method according to claim 1, characterized in that: in, Using high shear mixing equipment, various raw materials including treated base asphalt and rock asphalt mother liquor in a preset ratio are added to a mixing kettle, and the temperature and shear stress are controlled by a target model to obtain modified asphalt, including: A high shear mixing device with temperature control and shear stress control functions is used to weigh the treated base asphalt, rock asphalt mother liquor, modifier and aromatic oil in a predetermined proportion and place them in a mixing kettle in turn, and the total mass is controlled within the set value range; Controlling the temperature of the mixing kettle so that it follows a target temperature control function relationship, wherein the target temperature control function includes an initial temperature, a temperature variation range, a heating rate, and a periodic fluctuation parameter; Adjusting the shear stress of the mixing kettle so that it follows a target shear function relationship, wherein the target shear function includes a reference shear stress, a fluctuation amplitude and a periodic parameter, and intermittent shearing is achieved through a periodic switching function; The mixing operation is continued for a predetermined time and after completion the modified asphalt is transferred to a temperature-controlled container.

5. The preparation method according to claim 1, characterized in that: in, Aggregates of various particle sizes, recycled asphalt, modified asphalt and mineral powder in predetermined proportions are sequentially put into a forced mixing device, and dry-mixed and wet-mixed at a preset time sequence under temperature control conditions to prepare asphalt mixture, including: Weigh the modified asphalt, mineral powder, aggregates of various particle sizes and recycled asphalt in a predetermined proportion; Weighed aggregates of various particle sizes and recycled asphalt are put into a forced mixing device and dry mixed at a preset speed for a predetermined time; Modified asphalt is added to the dry-mixed mixture, and after a predetermined wet mixing time, the composite mineral powder is continuously stirred, and the temperature of the entire process is controlled within a preset range to prepare an asphalt mixture.

6. The preparation method according to claim 2, characterized in that: in, Control shear rate using a decaying sine function, including: γ(t)=γ0·e -kt ·sin(ωt), Wherein, γ(t) represents the shear rate at time t, γ0 represents the initial shear rate, and its value range includes 1000-2000s^-1, k represents the attenuation coefficient, and its value range includes 0.01-0.04s^-1, and ω represents the angular frequency, and its value range includes 0.15-0.6rad / s.

7. The preparation method according to claim 4, characterized in that: in, Make it follow the target temperature control function relationship, including: T(t)=T0+ΔT·(1-e -αt )·(1+βsin(θt)), Wherein, T(t) represents the temperature at time t, T0 represents the initial temperature, which is 140°C, ΔT represents the maximum temperature change, which is 40°C, α represents the heating rate coefficient, which is in the range of 0.005-0.009s^-1, β represents the temperature fluctuation coefficient, which is in the range of 0.1-0.2, and θ represents the temperature fluctuation angular frequency, which is in the range of 0.01-0.05rad / s.

8. The preparation method according to claim 4, characterized in that: in, Make it follow the target shear function relationship, including: τ(t)=τ0·(1+λsin(φt))·H(sin(ψt)), Among them, τ(t) represents the shear stress at time t, τ0 represents the basic shear stress, ranging from 1000 to 1750 Pa, λ represents the stress fluctuation coefficient, ranging from 0.2 to 0.4, φ represents the stress fluctuation angular frequency, ranging from 0.5 to 0.7 rad / s, ψ represents the pulse frequency, ranging from 0.1 to 0.2 rad / s, H() represents the step function, when x ≥ 0, H(x) = 1, otherwise H(x) = 0.

9. A rock asphalt composite modified asphalt mixture using the preparation method according to any one of claims 1 to 8, characterized in that: include: 66.43 units of No. 70 base asphalt, 18.2 units of rock asphalt mother liquor, 2.73 units of 6302 modifier, 3.64 units of aromatic oil, 9 units of mineral powder, 10 units of aggregate with particle size of 0-3mm, 3 units of aggregate with particle size of 3-6mm, 30 units of aggregate with particle size of 6-11mm, 28 units of aggregate with particle size of 11-16mm and 20 units of recycled asphalt.

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