Silent asphalt mixture and method for designing the same

Abstract

The application relates to the technical field of road engineering, and discloses a mute asphalt mixture and a design method thereof, wherein the asphalt mixture comprises asphalt and mineral aggregate, the mineral aggregate comprises coarse aggregate, fine aggregate and mineral powder, and the design method comprises the following steps: determining the skeleton void ratio of the coarse aggregate, determining the usage ratio of the coarse aggregate and the fine aggregate as qc:qf, synthesizing to obtain the mineral aggregate grading, measuring the actual void ratio, the coarse aggregate void ratio and the asphalt film thickness in the asphalt mixture, measuring the bleeding loss rate, testing the road performance, testing the surface texture characteristics and the tire vertical excitation, and obtaining the final proportioning of the mute asphalt mixture design. By adopting the surface texture characteristics and the tire vertical excitation displacement as double control indexes and combining the main skeleton void filling method, the road noise reduction performance and the durability of other road performances can be ensured while the noise reduction is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of road engineering, and discloses a mute asphalt mixture and a design method thereof. BACKGROUND

[0002] Tire / pavement coupling noise accounts for more than 80% of traffic pollution noise, and is a major public health problem affecting the life of residents along the road. Compared with passive noise reduction measures (sound barriers, soundproof walls, etc.), noise reduction asphalt pavement has the advantages of source control and blocking, and is an economical and effective way to reduce road noise.

[0003] However, the noise reduction asphalt pavement prepared from the asphalt mixture obtained by the existing design method has the technical bottleneck that the noise reduction performance and durability are difficult to balance, which limits the application of the noise reduction pavement. The widely used noise reduction asphalt pavement includes porous asphalt pavement, rubber asphalt pavement and thin layer asphalt overlay, among which the noise reduction performance of the porous asphalt pavement is the most remarkable. However, the porous structure of the porous asphalt pavement is prone to be blocked and the particles are prone to fall off, which leads to rapid decline of the noise reduction performance and short service life. Although the rubber asphalt pavement and the thin layer asphalt overlay have good durability under the premise of using high-performance asphalt binder, their noise reduction performance is far inferior to that of the porous asphalt pavement, and it is difficult to meet the noise reduction use demand.

[0004] Therefore, there is an urgent need for a new design method to solve the problem that the existing design method cannot design an asphalt mixture with excellent noise reduction performance and durability. SUMMARY

[0005] In view of the above defects, the present application aims to provide a mute asphalt mixture and a design method thereof, which can effectively solve the problem that the noise reduction performance and durability of the traditional noise reduction asphalt pavement are difficult to balance, and realize long-term durability of the noise reduction performance of the asphalt pavement.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] A design method of a mute asphalt mixture, wherein the asphalt mixture comprises asphalt and mineral aggregate, and the mineral aggregate comprises coarse aggregate, fine aggregate and mineral powder, comprising the following steps:

[0008] S1, determining the skeleton void ratio VCA of the coarse aggregate according to the blending ratio of each fraction in the coarse aggregate DRC ;

[0009] S2, taking the aggregate with a particle size of 0-2.36 mm as the fine aggregate, and determining the dosage ratio qc:qf of the coarse aggregate and the fine aggregate by using the main skeleton void filling method according to the asphalt dosage, the mineral powder dosage, the target void ratio and the skeleton void ratio of the coarse aggregate in the step S1;

[0010] S3, according to the ratio of the amount of coarse aggregate and fine aggregate in step S2, according to the gradation combination of coarse aggregate, fine aggregate and mineral powder, the mineral aggregate gradation is synthesized;

[0011] S4, the asphalt mixture is prepared according to the mineral aggregate gradation obtained in step S3, the actual void ratio, coarse aggregate gap ratio and asphalt film thickness in the asphalt mixture are measured, if qualified, the next step test is entered, if unqualified, it is returned to step S1 or step S2 for correction; the actual void ratio in the asphalt mixture is 3%≤target void ratio≤6%, the judgment standard for the qualified coarse aggregate gap ratio is ≤VCA DRC , and the judgment standard for the qualified asphalt film thickness is ≥15μm;

[0012] S5, the bleeding loss rate of the qualified asphalt mixture obtained in step S4 is determined, if qualified, the next step test is entered, if unqualified, it is returned to step S2 for correction; the judgment standard for the qualified bleeding loss rate is <0.3%;

[0013] S6, the road performance test is carried out on the qualified asphalt mixture obtained in step S5, if qualified, the next step test is entered, if unqualified, it is returned to step S1 or step S2 for correction;

[0014] S7, the surface texture characteristics and tire vertical excitation test are carried out on the qualified asphalt mixture prepared in step S6, if qualified, the synthetic mineral aggregate gradation and the asphalt amount are used as the final ratio of the quiet asphalt mixture design, if unqualified, it is returned to step S1 or step S2 for correction.

[0015] Preferably, the performance requirements of the asphalt are 60℃ complex shear modulus G*>12kPa, 60℃ dynamic viscosity >580,000Pa·s, and 25℃ elastic recovery >98%.

[0016] Preferably, the method for determining the skeleton gap ratio of the coarse aggregate in step S1 comprises: testing the close-packed density of the coarse aggregate by dry ramming method, and calculating the skeleton gap ratio of the coarse aggregate according to formula 1,

[0017]

[0018] In formula 1, VCA DRC is the skeleton gap ratio of the coarse aggregate, %; γ CA is the apparent density of the coarse aggregate, g / cm 3 ; γ s is the close-packed density of the coarse aggregate skeleton, g / cm 3 ;

[0019] The asphalt amount in step S2 is determined by oil stone ratio, the oil stone ratio is 7.2-8.5%, the amount of mineral powder is 2-6% of the mass of the mineral aggregate, and the target void ratio is 3-6%;

[0020] The method for determining the ratio of coarse aggregate and fine aggregate in step S3 includes: the total of the volume of fine aggregate, the volume of mineral powder, the volume of asphalt and the target void volume of asphalt mixture is equal to the void volume of coarse skeleton, and the ratio of coarse aggregate and fine aggregate is obtained, and the calculation process satisfies equations 2 and 3:

[0021] p c +p x +p k = 100 Equation 2

[0022]

[0023] In equations 2 and 3, p c , p x , p k , p l are the mass percentages of coarse aggregate, fine aggregate, mineral powder and asphalt in the mineral aggregate, %; VCA DRC is the skeleton void ratio of coarse aggregate, %; VV is the target void ratio, %; γ x , γ k are the apparent densities of fine aggregate and mineral powder, g / cm 3 ; γ l is the density of asphalt, g / cm 3 ; γ s is the tight packing density of coarse aggregate skeleton, g / cm 3 .

[0024] Preferably, before step S4, the mineral aggregate grading synthesized in step S3 needs to be verified, and if qualified, it enters step S4, otherwise it returns to step S2 for correction.

[0025] The judgment standard for the qualification of the mineral aggregate grading is within the following range:

[0026]

[0027] Preferably, in step S4, when the coarse aggregate void ratio of the asphalt mixture is unqualified, it returns to step S1 to increase the blending ratio of the larger particle grade in the coarse aggregate, or returns to step S2 to reduce the amount of mineral powder; when the asphalt film thickness is unqualified, it returns to step S2 to increase the amount of asphalt.

[0028] Preferably, in step S6, the judgment standard for qualification is that the asphalt mixture should simultaneously satisfy the following road performance:

[0029] 1) The dynamic stability of 60℃ rutting is not less than 3000 times / mm;

[0030] 2) Under the test condition of 15℃, 1000με, the four-point bending fatigue life is not less than 200,000 times;

[0031] 3) Kentorbo flying loss is not greater than 8%.

[0032] Preferably, the qualified judgment criteria in step S7 is that the surface texture characteristics of the pavement test piece prepared by the asphalt mixture is that the texture depth is greater than 0.65mm, the surface skewness S sk ≤-0.8mm, and the vertical excitation displacement of the tire is less than 1.0mm.

[0033] Preferably, in step S7, when any one of the texture depth and the surface skewness does not meet the requirements, return to step S1 to increase the mixing proportion of the larger particle grade in the coarse aggregate, or return to step S2 to reduce the amount of mineral powder; when the vertical excitation displacement of the tire does not meet the requirements, return to step S1 to reduce the mixing proportion of the larger particle grade in the coarse aggregate, or return to step S2 to increase the amount of asphalt.

[0034] Preferably, the vertical excitation of the tire is obtained by three-dimensional modeling and finite element software simulation test, wherein the Yeoh constitutive model is selected as the rubber model of the tire.

[0035] The method comprises the following steps:

[0036] S7.1 scans the surface structure of the rutting plate test piece made of asphalt mixture by using a high-precision line laser scanner, and obtains surface structure elevation point cloud matrix data;

[0037] S7.2 removes the overlapping data in the surface structure elevation point cloud matrix data, performs noise reduction, skewness removal and zeroing processing on the data, establishes a three-dimensional pavement in the Abaqus finite element software, and uses Prony series to represent the viscoelastic properties of the pavement;

[0038] S7.3 establishes a three-dimensional tire model in the finite element software, wherein the tire model includes a carcass, a tread and a sidewall, and the Yeoh constitutive model is selected as the rubber model of the tire;

[0039] S7.4 defines and sets the tread and the three-dimensional pavement as surface-to-surface contact through the Interaction module, sets the contact surface as a contact mode with a fixed friction coefficient, and sets the friction coefficient;

[0040] S7.5 moves the tire downward to achieve preliminary contact with the pavement, then releases the downward constraint of the tire, makes the tire rebound on the pavement, but still in the contact state;

[0041] S7.6 applies a concentrated force to simulate that the tire receives the automobile load;

[0042] S7.7 applies the speed and angular velocity of the tire to simulate the rolling of the tire on the pavement;

[0043] S7.8 Set the test time of the tire center point, so that the tire rolling distance in the test time covers the entire length of the three-dimensional road surface, and the displacement data of the tire center point is extracted after the test is completed, and the vertical excitation displacement of the tire is the height difference between the highest point and the lowest point of the tire center point in the entire stroke.

[0044] A mute asphalt mixture is designed by the design method, the void ratio of the mute asphalt mixture is 3-6%, and the maximum nominal particle size is 3-8mm; the construction depth of a pavement test piece prepared from the mute asphalt mixture is >0.65mm, the surface skewness S sk ≤-0.8mm.

[0045] The technical scheme provided by the application can include the following beneficial effects:

[0046] 1. By adopting the surface texture feature and the vertical excitation displacement of the tire as double control indexes, and combining the main framework void filling method, the durability of the road noise reduction performance and other road performances can be ensured while the noise reduction is realized.

[0047] 2. By controlling the double design principles of the surface texture feature and the vertical excitation displacement value of the tire, the design of the mute asphalt mixture is more purposeful, normative and flexible. The mute asphalt mixture with the surface flatness and deep negative texture structure and the significant damping and vibration damping effect can be obtained, and the noise reduction performance of the asphalt pavement can be significantly improved. Compared with the traditional AC-13 pavement, the tire / pavement noise is reduced by 3-10dB, and meanwhile, the problem that the noise reduction performance and the durability of the traditional noise reduction asphalt pavement are difficult to balance can be effectively solved, and the long-term durability of the noise reduction performance of the asphalt pavement is realized.

[0048] 3. The thick oil film (the oil film thickness is greater than or equal to 15um) is adopted to realize the damping and vibration damping, reduce the vertical excitation displacement of the tire, further ensure the noise reduction performance, and realize that the tire / pavement coupling noise generated by the pavement paved by the designed mixture is reduced by 3-10dB compared with the traditional AC-13 pavement.

[0049] 4. By reducing the maximum nominal particle size of the mineral aggregate to 3-8mm (the conventional maximum nominal particle size is greater than or equal to 13mm), the surface roughness of the pavement is reduced, the impact of the pavement on the tire is reduced, and the tire vibration noise is reduced. The gradation range is obtained through a large number of tests, and can be used to preliminarily judge whether the obtained asphalt mixture meets the maximum compaction theory and the framework embedded structure. Compared with the conventional gradation range, the coarse aggregate in the gradation range accounts for a larger proportion, the amount of powder (<0.075mm) is less, the asphalt is used to replace part of the fine aggregate, the interference on the framework is reduced, the material toughness is enhanced, and when the asphalt content is high, the material viscosity is improved, and the damping and noise reduction performance is improved.

[0050] 5. The balance design of noise reduction and skid resistance of asphalt mixture is realized by detecting the construction depth and surface deflection in the surface texture features of the road surface test piece.

[0051] 6. By adopting the main skeleton filling method, the deep negative texture structure can be maximally ensured under the condition of dense structure, for example, in the case of rough aggregate skeleton embedding, no other materials are filled, at this time the maximum negative texture can be formed, but the actual void ratio is difficult to meet the requirements, therefore, fine aggregate, mineral powder and asphalt are filled to achieve the target void ratio and maximally maintain the deep negative texture, if the amount of filling material continues to increase, the rough aggregate skeleton structure will be destroyed, the void between the stones on the road surface will be filled, and the texture structure will be destroyed. By adopting the main skeleton void filling method, the depth of the negative texture between the aggregates during the flattening of the road surface under the condition of dense structure is maximally ensured, the air cavity air is provided with a passage for being discharged during the rolling of the tire, and the purpose of reducing the air pumping noise is achieved.

[0052] 7. The ability of the road surface to stimulate the tire is characterized by the laser scanning data and the simulation model establishment method, so as to determine whether it meets the limited requirements. For tire / road surface simulation, the mechanical properties of the tire rubber material have a decisive influence on the accuracy of the simulation result as a key component. The tire rubber material usually shows high nonlinearity and large deformation capacity. In order to accurately describe these complex mechanical behaviors, it is crucial to select a suitable constitutive model. The hyperelastic constitutive model of rubber material is mainly divided into two categories: molecular network model and phenomenological model. The molecular network model has a clear physical meaning and is suitable for understanding the behavior of rubber materials from the microstructure, but it may not be accurate under complex deformation and multi-axial loading conditions. The phenomenological model describes the elastic properties of the material by constructing a strain energy density function, and does not directly involve microphysical parameters, but determines the model parameters through experimental data. Therefore, the Yeoh constitutive model in the phenomenological model is adopted as the rubber model of the tire. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 The schematic diagram of the positive texture and the negative texture. DETAILED DESCRIPTION

[0054] In order to facilitate the understanding of the present application, the present application will be described more fully below. The present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0055] The specific technology or condition not specified in the embodiments is carried out according to the technology or condition described in the literature in the art or according to the product instruction. The reagent or instrument not specified by the manufacturer is a conventional product that can be obtained by purchase.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. The following describes embodiments of the application.

[0057] Embodiments of the application are described below, by way of example only, with reference to the accompanying drawings.

[0058] A design method of a quiet asphalt mixture, wherein the asphalt mixture comprises asphalt and mineral aggregate, the mineral aggregate comprises coarse aggregate, fine aggregate and mineral powder, comprising the following steps:

[0059] S1, determining the VCA of the coarse aggregate according to the blending ratio of each fraction in the coarse aggregate DRC ;

[0060] S2, taking the aggregate with a particle size of 0-2.36 mm as the fine aggregate, determining the ratio of the coarse aggregate to the fine aggregate qc:qf by the main skeleton void filling method according to the asphalt content, the mineral powder content, the target air void and the VCA of the coarse aggregate in step S1;

[0061] S3, synthesizing the mineral aggregate gradation according to the ratio of the coarse aggregate to the fine aggregate in step S2 and the gradation combination of the coarse aggregate, the fine aggregate and the mineral powder;

[0062] S4, preparing the asphalt mixture according to the mineral aggregate gradation obtained in step S3, determining the actual air void, the coarse aggregate void and the asphalt film thickness in the asphalt mixture, if qualified, entering the next step, if unqualified, returning to step S1 or step S2 for correction; the judgment standard of the actual air void in the asphalt mixture is 3%≤target air void≤6%, the judgment standard of the qualified coarse aggregate void is ≤VCA DRC , and the judgment standard of the qualified asphalt film thickness is ≥15μm;

[0063] S5, determining the bleeding loss rate of the qualified asphalt mixture obtained in step S4, if qualified, entering the next step, if unqualified, returning to step S2 for correction; the judgment standard of the qualified bleeding loss rate is <0.3%;

[0064] S6, testing the road performance of the road test piece prepared from the qualified asphalt mixture obtained in step S5, if qualified, entering the next step, if unqualified, returning to step S1 or step S2 for correction;

[0065] S7, surface texture characteristics and tire vertical excitation test are carried out on the qualified asphalt mixture obtained in step S6, if qualified, the synthetic mineral aggregate gradation and the asphalt content are taken as the final ratio of the quiet asphalt mixture design, if not qualified, it is returned to step S1 or step S2 for correction.

[0066] The traditional pavement design method is a balanced design between different road performances, and lacks design and evaluation methods of noise reduction performance, so it is difficult to realize noise reduction pavement design. The surface texture characteristics and tire vertical excitation displacement are used as double control indexes, and the main skeleton void filling method is combined, so that the noise reduction is realized while the durability of the pavement noise reduction performance and other road performances is ensured.

[0067] Through the double design principle of controlling the surface texture characteristics and tire vertical excitation displacement value, the design of the quiet asphalt mixture is more purposeful, normative and flexible. The asphalt mixture with smooth surface and deep negative texture structure and significant damping and vibration damping effect can be obtained, which can significantly improve the noise reduction performance of the asphalt pavement, reduce the tire / pavement noise by 3-10 dB compared with the traditional AC-13 pavement, and effectively solve the problem that the noise reduction performance and durability of the traditional noise reduction asphalt pavement are difficult to balance, and realize the long-term durability of the noise reduction performance of the asphalt pavement.

[0068] The actual void ratio in the asphalt mixture is controlled in the range of 3-6%, which provides space for asphalt to creep under vehicle load, and avoids more than 6% to make the mechanical properties, water damage resistance and other properties of the asphalt mixture decrease.

[0069] The thick oil film (oil film thickness ≥ 15 μm) is used to realize damping and vibration damping, reduce the tire vertical excitation displacement, further ensure the noise reduction performance, and realize that the tire / pavement coupling noise generated by the pavement paved by the designed mixture is reduced by 3-10 dB compared with the traditional AC-13 pavement.

[0070] Preferably, the method for determining the blending ratio of each fraction of coarse aggregate comprises: when one fraction of coarse aggregate is selected, the coarse aggregate of this fraction accounts for 100% of the coarse aggregate; when two fractions of 5-8 mm and 3-5 mm are selected, the blending ratio of the 5-8 mm fraction and the 3-5 mm fraction is (2.5-3.5):1; when the fraction of coarse aggregate exceeds two, a plurality of blending ratios should be set, the tight packing density is measured, and the group with larger tight packing density is selected as the blending ratio of each fraction of coarse aggregate. The present application does not have special requirements for the selection of each fraction of coarse aggregate, and the selection method known to those skilled in the art can be used.

[0071] Preferably, the performance requirements of the asphalt are 60℃ complex shear modulus G*>12kPa, 60℃ dynamic viscosity >580,000 Pa·s, and 25℃ elastic recovery >98%.

[0072] The traditional noise reduction pavement is limited by insufficient asphalt performance, so that the surface aggregate is easy to peel off, the noise reduction performance declines fast, and long-term noise reduction is difficult to achieve, in order to solve the above problems, the high-viscosity and high-elasticity modified asphalt is used as the binder, the binder has strong adhesion, the high-viscosity and high-elasticity modified asphalt can be used to prepare the mixture with high wear resistance, so that the long-term noise reduction performance of the pavement structure is ensured, meanwhile, the binder has excellent viscoelasticity, the damping and vibration damping effect of the mixture is improved, the generation of tire vibration noise is reduced, and the noise reduction performance of the pavement is further improved.

[0073] Preferably, the method for determining the skeleton gap rate of the coarse aggregate in step S1 comprises: testing the close-packed density of the coarse aggregate by using the dry ramming method, and calculating the skeleton gap rate of the coarse aggregate according to formula 1,

[0074]

[0075] In formula 1, VCA DRC is the skeleton gap rate of the coarse aggregate, %; γ CA is the apparent density of the coarse aggregate, g / cm 3 ; γ s is the close-packed density of the skeleton of the coarse aggregate, g / cm 3 ;

[0076] The asphalt content in step S2 is determined by the oil-stone ratio, the oil-stone ratio is 7.2-8.5%, the mineral powder content is 2-6% of the mass of the mineral aggregate, and the target air void rate is 3-6%;

[0077] In step S3, the method for determining the ratio of the coarse aggregate and the fine aggregate by using the main skeleton void filling method comprises: the sum of the volumes of the fine aggregate, the mineral powder, the asphalt and the target air void volume of the asphalt mixture is equal to the void volume of the coarse skeleton, so that the ratio of the coarse aggregate and the fine aggregate is obtained, and the calculation process satisfies formula 2 and formula 3 equations:

[0078] p c +p x +p k = 100 formula 2;

[0079]

[0080] In formula 2 and formula 3: p c , p x , p k , p l are the mass percentages of the coarse aggregate, the fine aggregate, the mineral powder and the asphalt in the mineral aggregate, %; VCA DRC is the skeleton gap rate of the coarse aggregate, %; VV is the target air void rate, %; γ x , γ k are the apparent densities of the fine aggregate and the mineral powder, g / cm 3 ; γl Density of asphalt, g / cm 3 ; γ s Tight packing density of coarse aggregate skeleton, g / cm 3 .

[0081] wherein, formula 1 is used to calculate the skeleton air void of coarse aggregate, and is a judgment index for judging whether the performance of the asphalt mixture after molding is a skeleton interlocking structure. The main skeleton void filling method refers to a design idea of filling asphalt and fine aggregate into the skeleton structure formed by the coarse aggregate to form a dense structure (air void of 3-6%) on the basis of the skeleton structure formed by the coarse aggregate. After the skeleton air void of the coarse aggregate is obtained, the amount ratio of the coarse aggregate and the fine aggregate is determined by using the main skeleton void filling method according to the asphalt amount, the mineral powder amount, the target air void and the skeleton air void of the coarse aggregate.

[0082] Formula 2 and formula 3 are the calculation process of determining the amount ratio of the coarse aggregate and the fine aggregate. Formula 2 refers to that the mass percentage of the coarse aggregate, the fine aggregate and the mineral powder is added to 100%. Formula 3 refers to the volume relationship of the coarse aggregate gap and the filled fine aggregate, mineral powder and asphalt. The amount ratio of the coarse aggregate and the fine aggregate is obtained by solving the two equations. In formula 2 and formula 3, the apparent density of the fine aggregate and the mineral powder and the density of the asphalt can be obtained by testing and calculating according to the “Highway Engineering Aggregate Test Specification” (JTG E42-2005) and the “Highway Engineering Asphalt and Asphalt Mixture Test Specification” (JTG E20-2011).

[0083] The noise reduction performance of the porous asphalt pavement in the traditional noise reduction pavement comes from the porous sound absorption structure. The air void of the noise reduction pavement with the porous structure is usually 15-20%, but the problem of rapid decline of the noise reduction performance caused by the air void blockage cannot be avoided. Moreover, the porous structure is prone to water damage and aggregate peeling, causing the service life of the pavement to attenuate. Therefore, the dense structure is adopted in the present application, the target air void is set to 3-6%, and the asphalt amount is increased, so that the oil stone ratio reaches 7.2-8.5%, the high oil film not only ensures the durability of the noise reduction pavement, but also plays the role of damper between the stones, reduces the tire vibration noise, ensures the durability while ensuring the noise reduction performance, and fundamentally solves the technical problem of rapid attenuation of the noise reduction performance of the porous noise reduction asphalt pavement caused by the air void blockage and the surface particle peeling. Moreover, the skeleton interlocking stability of the dense structure and the strong anti-cracking effect of the high asphalt oil film ensure that the asphalt mixture has good structure performance of anti-rutting deformation, anti-fatigue cracking and anti-shear deformation.

[0084] Preferably, before step S4, the mineral aggregate gradation synthesized in step S3 needs to be verified. If it is qualified, it enters step S4, otherwise it returns to step S2 for correction.

[0085] The judgment standard for the qualified mineral aggregate gradation is within the following range:

[0086]

[0087] It is worth mentioning that by reducing the maximum nominal particle size of the mineral aggregate to 3-8 mm (conventionally 13 mm or more), the surface roughness of the road surface is reduced, the impact of the road surface on the tire is reduced, and the tire vibration noise is reduced. The gradation range is obtained through a large number of tests, which can be used to preliminarily judge whether the obtained asphalt mixture meets the maximum compaction theory and the skeleton embedded structure. The gradation range has a larger proportion of coarse aggregate than the conventional gradation range, and a smaller amount of powder (<0.075 mm). By using asphalt instead of part of the fine aggregate, the interference with the skeleton is reduced, the material toughness is enhanced, and at the same time, the material viscosity is improved when the asphalt content is high, and the damping noise reduction performance is improved. The screening method refers to "Highway Engineering Aggregate Test Regulations" (JTG E42-2005). In addition, in step S3, there is no special requirement for the way of synthesizing the mineral aggregate gradation. According to the gradation combination of coarse aggregate, fine aggregate and mineral powder, the specific way of synthesizing the mineral aggregate gradation is the prior art, and the synthesis method known to those skilled in the art can be used.

[0088] Preferably, if the synthesized mineral aggregate gradation is unqualified, return to step S2 for correction, and appropriately fine-tune the ratio of the coarse and fine aggregates obtained in step S2. The correction principle is: if the synthesized gradation exceeds the upper limit of the mineral aggregate gradation range of the quiet noise reduction asphalt mixture, increase the amount of coarse aggregate and reduce the amount of fine aggregate; if the synthesized gradation is lower than the lower limit of the mineral aggregate gradation range of the quiet noise reduction asphalt mixture, reduce the amount of coarse aggregate and increase the amount of fine aggregate.

[0089] Preferably, in step S4, when the coarse aggregate void ratio of the asphalt mixture is unqualified, return to step S1 to increase the blending ratio of the larger particle size range in the coarse aggregate, or return to step S2 to reduce the amount of mineral powder; when the asphalt film thickness is unqualified, return to step S2 to increase the amount of asphalt.

[0090] In specific embodiments, such as when the selected coarse aggregate has multiple particle size ranges, when the coarse aggregate void ratio of the asphalt mixture is unqualified in step S4, return to step S1 to increase the blending ratio of the larger particle size range in the coarse aggregate, and increase by 0.3-0.5 at a time, such as from 2:1 to (2.3-2.5):1. When the coarse aggregate void ratio of the asphalt mixture is unqualified, return to step S2 to reduce the amount of mineral powder, and the amount of mineral powder is reduced by 0.5-1% each time, preferably 0.5% or 1%. If the selected coarse aggregate is selected as one range, return to step S2 to reduce the amount of mineral powder, or appropriately fine-tune the ratio of the coarse and fine aggregates obtained in step S2 to reduce the amount of fine aggregate.

[0091] In specific embodiments, when the asphalt film thickness is unqualified, return to step S2, and increase the asphalt content by increasing the oil-stone ratio by 0.3-0.5%.

[0092] When the asphalt mixture simultaneously satisfies the two conditions of coarse aggregate void ratio ≤ VCA DRC and asphalt film thickness ≥ 15 μm, the qualified asphalt mixture is subjected to determination of the bleeding loss rate, and the qualified judgment standard of the bleeding loss rate is < 0.3%.

[0093] The maximum asphalt content of the asphalt mixture can be determined by determining the bleeding loss rate, and whether the asphalt content is within the appropriate asphalt content range of the synthetic gradation is tested. The determination method of the bleeding loss rate has no special requirements, and can be determined by using the detection standard well known by those skilled in the art.

[0094] Preferably, in step S5, when the bleeding loss rate is unqualified, return to step S2 for correction, and decrease the asphalt content by decreasing the oil-stone ratio by 0.3-0.5%.

[0095] Preferably, in step S6, the qualified judgment standard is that the asphalt mixture should simultaneously satisfy the following road performances:

[0096] 1) 60°C rutting dynamic stability is not less than 3000 times / mm;

[0097] 2) Four-point bending fatigue life under the test conditions of 15°C and 1000 με is not less than 200,000 times;

[0098] 3) Kentucky Spreading Loss is not greater than 8%.

[0099] Preferably, if the rutting dynamic stability of the asphalt mixture does not satisfy the above road performance requirements, increase the blending ratio of the larger particle grade in the coarse aggregate in step S1, or decrease the amount of mineral powder in step S2 for correction, and the amount of mineral powder is decreased by 0.5-1% each time.

[0100] Preferably, if either the fatigue life or the bleeding loss rate of the asphalt mixture does not satisfy the above road performance requirements, increase the asphalt content in step S2 for correction, and increase the asphalt content by increasing the oil-stone ratio by 0.3-0.5% each time.

[0101] The skeleton structure is determined to be reasonable by the rutting dynamic stability, and the asphalt content is determined to be lower than the design lower limit by the combination of the four-point bending fatigue life and the Kentucky Spreading Loss rate. It should be noted that the tests of various road performances have no time sequence, and the determination methods of the four-point bending fatigue life, the Kentucky Spreading Loss rate and the rutting dynamic stability have no special requirements, and can be determined by using the detection standard well known by those skilled in the art.

[0102] Preferably, the qualified judgment criteria in step S7 is that the surface texture characteristics of the pavement test piece prepared by the asphalt mixture are that the texture depth is greater than 0.65 mm, the surface skewness S sk ≤-0.8 mm, and the vertical excitation displacement of the tire is less than 1.0 mm.

[0103] The surface texture of the pavement directly affects the contact state of the tire and the pavement, and further affects the pavement skid resistance and the generation of tire-pavement noise. By detecting the texture depth and the surface skewness in the surface texture characteristics of the pavement test piece, the balance design of the noise reduction and skid resistance of the asphalt mixture is realized. The pavement test piece is an indoor formed rutting plate test piece prepared according to the “Highway Engineering Asphalt and Asphalt Mixture Test Regulations” (JTG E20-2011 T0703).

[0104] The texture depth refers to the average depth of the opening pores of the uneven surface of the pavement in a certain area, and is an important index of the pavement roughness, and is mainly used for evaluating the macro roughness and skid resistance of the pavement surface. The test method refers to the “Highway Subgrade and Pavement Field Test Regulations” (JTG 3450-2019 T0961).

[0105] The surface skewness is a parameter for characterizing the concave-convex shape of the surface texture, and is an index for testing whether a negative texture is formed. The negative texture structure is formed by using the main skeleton void filling method for material design, and the texture structure is formed on the surface of the asphalt mixture. The negative texture structure can ensure that the skid resistance of the road surface is maintained when a smaller maximum nominal particle size is used, and can also reduce the generation of pump noise.

[0106] As shown in Figure 1 , the negative texture refers to the narrow and deep gap formed between the stones on the surface, and the deep negative texture refers to the deep gap. In the present application, the texture with S sk ≤-0.8 mm is defined as the deep negative texture. When the tire contacts the positive texture of the pavement, it will be embedded into the gap and squeeze most of the space in the gap. For the negative texture, the surface wave peak is wide, which can resist the embedding of the tire, and only a small part of the air exclusion space is squeezed. When the tire rolls on the pavement, if the volume of air squeezed out is the same each time, when the pavement surface forms a negative texture, the deeper the texture, the larger the air exclusion space and the smaller the air flow rate. By reducing the air flow rate, the air pump noise generated by the high-speed flow of air is reduced.

[0107] The asphalt pavement formed by rolling molding will form a negative texture structure. The surface texture and the gap of the asphalt pavement determine the size of the air pump noise generated by the tire and the pavement.

[0108] It is worth mentioning that the main skeleton filling method used in the design method can maximize the guarantee of deep negative texture structure in the case of dense structure. For example, in the case of coarse aggregate skeleton embedding, no other materials are filled, and the maximum negative texture can be formed at this time. However, the actual void ratio is difficult to meet the requirements, so fine aggregate, mineral powder and asphalt are filled to achieve the target void ratio and maximize the maintenance of deep negative texture. If the amount of filling material continues to increase, the coarse aggregate skeleton structure will be destroyed, the void between the stones on the surface of the road will be filled, and the texture structure will be destroyed. By using the main skeleton void filling method, the depth of the negative texture between the aggregates is maximized when the road surface is flat, which provides a channel for the air in the cavity to be discharged when the tire rolls, thereby achieving the purpose of reducing air pumping noise.

[0109] Surface skewness S sk The symmetry or concave-convex tendency of the surface texture height probability density curve is measured,

[0110] S sk When S < 0, the road surface texture is negative, which ensures that the road surface has noise reduction performance for air pumping noise, and is calculated according to formula 7:

[0111]

[0112] Wherein, Z i is the height of the i-th sampling point; is the surface average height, which is the average value of the height Z i of all sampling points; n is the total number of sampling points; Sa is the arithmetic mean of the absolute value of the height deviation of all points in the surface area from the reference surface, and the reference surface height is the surface average height

[0113] The tire vibration noise generated by the vibration of the surface pattern block of the tire excited by the road surface is the main source of tire-road noise. When the noise occurs, the tire will also produce vertical displacement. Due to the complexity of the acoustic mechanism model, it is difficult to truly predict noise, so a relatively simple vertical excitation model of the tire is used to quantify the excitation ability of the road surface to the tire, which can better evaluate the noise reduction performance of the asphalt mixture.

[0114] Preferably, in step S7, when either the construction depth or the surface skewness does not meet the requirements, return to step S1 to increase the mixing proportion of the larger particle size range in the coarse aggregate, or return to step S2 to reduce the amount of mineral powder; when the vertical excitation displacement of the tire does not meet the requirements, return to step S1 to reduce the mixing proportion of the larger particle size range in the coarse aggregate, or return to step S2 to increase the amount of asphalt.

[0115] Preferably, when the vertical excitation displacement of the tire does not meet the requirement, if the construction depth is greater than 1.5 mm, return to step S1 to reduce the mixing proportion of the larger particle grade in the coarse aggregate; if the construction depth is less than 1.5 mm, return to step S2 to increase the amount of asphalt.

[0116] Preferably, the vertical excitation of the tire is obtained by three-dimensional modeling and finite element software simulation test, wherein the Yeoh constitutive model is selected as the rubber model of the tire.

[0117] The method comprises the following steps:

[0118] S7.1, a high-precision line laser scanner is used to scan the surface structure of the rut plate test piece made of asphalt mixture, and surface structure elevation point cloud matrix data is obtained;

[0119] S7.2, overlapping data in the surface structure elevation point cloud matrix data is removed, and the data is subjected to noise reduction, declination removal and zero setting, a three-dimensional pavement is established in the Abaqus finite element software, and Prony series is used to represent the viscoelastic properties of the pavement;

[0120] S7.3, a three-dimensional tire model is established in the finite element software, and the Yeoh constitutive model is selected as the rubber model of the tire.

[0121] S7.4, the tread and the three-dimensional pavement are defined and set as surface-to-surface contact through the Interaction module, the contact surface is set as a contact mode with a fixed friction coefficient, and the friction coefficient is set.

[0122] S7.5, the tire is moved downward to achieve preliminary contact with the pavement, and then the downward constraint of the tire is released, so that the tire rebounds on the pavement but is still in contact.

[0123] S7.6, a concentrated force is applied to simulate that the tire receives the load of the automobile.

[0124] S7.7, the speed and angular velocity of the tire are applied to simulate that the tire rolls on the pavement.

[0125] S7.8, the test time of the center point of the tire is set so that the travel of the tire during the test time covers the entire length of the three-dimensional pavement, and after the test is completed, the displacement data of the center point of the tire is extracted, and the vertical excitation displacement of the tire is the height difference between the highest point and the lowest point of the center point of the tire along the vertical direction during the entire travel.

[0126] The ability of the pavement to excite the tire is characterized by the laser scanning data and the simulation model establishment method, so as to determine whether it meets the limited requirements. In specific embodiments, the scanned rut plate test piece data can be repeatedly spliced to form a three-dimensional pavement, so as to obtain better simulation test results.

[0127] In step S7.2, the data is denoised using a denoising method commonly used in surface texture data processing, such as Gaussian filtering or median filtering. The data is de-skewed and zeroed. First, the x and y coordinates corresponding to the elevation data are extracted to form a grid coordinate system. Then, a plane is fitted through linear regression, and the tilt error of each point is calculated. Finally, the actual elevation value is subtracted from the fitted plane value to obtain the corrected elevation data, eliminating the systematic error caused by the tilt. The core idea of this processing method is to regard the road surface tilt as a global trend, find the mathematical description of this trend through plane fitting, and use this description to correct the data. The processed elevation data can more truly reflect the original topography of the road surface. Using Abaqus finite element software, a three-dimensional road surface is established based on the processed data. The conventional characterization method Prony series is used to characterize the viscoelastic properties of the road surface, and the damping properties of the asphalt mixture are incorporated into the model.

[0128] It is worth noting that in step S7.3, for tire / road simulation, the tire rubber material is a key component, and its mechanical properties have a decisive influence on the accuracy of the simulation results. Tire rubber materials usually exhibit high nonlinearity and large deformation capability. To accurately describe these complex mechanical behaviors, it is crucial to choose a suitable constitutive model.

[0129] The hyperelastic constitutive model of rubber materials can be mainly divided into two categories: molecular network model and phenomenological model. The molecular network model has a clear physical meaning and is suitable for understanding the behavior of rubber materials from the perspective of microstructure, but it may not be accurate under complex deformation and multi-axial loading conditions. The phenomenological model describes the elastic properties of the material by constructing a strain energy density function, without directly involving microphysical parameters, but determining the model parameters through experimental data. Therefore, the Yeoh constitutive model in the phenomenological model is used as the rubber model of the tire. The Yeoh constitutive model is as shown in formula 8, which is characterized by 6 parameters: C 10 , C 20 , C 30 , and D1, D2, and D3. C 10 represents the initial shear modulus of the rubber material, which is generally positive, and its size represents the initial shear modulus; C 20 represents the softening parameter modulus of the rubber material, and the stress-strain curve of the rubber material is S-shaped, and the size of C 20 represents the softening degree of the rubber material; C 30 represents the hardening parameter modulus of the rubber material, and its value size represents the hardening degree of the rubber material after softening. When D represents the compressibility of the rubber material, the rubber material is generally approximately compressible. In an embodiment, the parameters of the rubber material of the tire are set as follows: D1=7.25×10 -8 ,

[0130] D2 = 0, D3 = 0

[0131]

[0132] wherein, is the first strain tensor invariant, J is the volume ratio after deformation to that before deformation.

[0133] The material parameters of the Yeoh constitutive model are shown in Table 1 below:

[0134] Table 1 Material parameters of Yeoh constitutive model

[0135]

[0136] A three-dimensional tire model is established using real tire dimensions. In one embodiment, a 205 / 55R16 radial tire is taken as the modeling object, wherein 205 represents that the tire tread width is 205 mm; 55 represents that the tire flatness ratio, i.e., the ratio of the tire section height to the tire tread width, is 55 (%); and R16 represents that the tire can adopt a rim diameter of 16 inches.

[0137] In step S7.4, the friction coefficient is set to 0.5, which is a value between high friction and low friction. In dynamic simulation, an extremely high friction coefficient sometimes introduces numerical calculation difficulties (such as iteration not converging, contact force oscillating sharply). Setting the friction coefficient to 0.5 can provide good numerical stability, reduce the risk of calculation failure, and ensure calculation efficiency.

[0138] In step S7.5, the tire is simulated to be in contact with the road surface in a real situation, and the overall rolling is divided into four steps: moving the tire downward to make it initially contact with the road surface; ending the downward movement of the tire to make the tire bounce on the road surface but still in contact with the road surface; applying a concentrated force to simulate the tire receiving the load of the car; and applying the speed and angular velocity of the tire to simulate the tire rolling on the road surface. By dividing the overall rolling, the model convergence is ensured and calculation failure is avoided.

[0139] In step S7.6, the vertical normal force of 3.5 kN is applied to the tire with reference to the quarter car weight of a commonly used small car.

[0140] In step S7.7, in one embodiment, the speed is set to 20 m / s and the angular velocity is set to 65 rad / s, which has a good sampling effect. As a simple adjustment, other speed and angular velocity parameters can also be used.

[0141] A mute asphalt mixture is designed by the design method described above, the void ratio of the asphalt mixture is 3-6%, and the maximum nominal particle size is 3-8 mm; the structure depth of a road test piece prepared therefrom is > 0.65 mm, the surface skewness S issk ≤-0.8mm.

[0142] The noise-reducing asphalt mixture of the present invention produces a smooth surface texture for the noise-reducing pavement, while also having a deep negative texture, resulting in good noise reduction effect and long service life.

[0143] Example 1

[0144] The steps for designing the GT-8 gradation of silent asphalt mixture are as follows:

[0145] S1. Conventional asphalt performance and rheological properties tests were conducted on the high-viscosity and high-elasticity modified asphalt. The test results are shown in Table 2.

[0146] Table 2. Performance Test Results and Technical Requirements of High-Viscosity and High-Elasticity Modified Asphalt

[0147]

[0148] The sieving results of the diabase used in this gradation design are shown in Table 3:

[0149] Table 3 Screening results of mineral materials of various specifications

[0150]

[0151] The coarse aggregate is divided into two grades: 3-5mm and 5-8mm. The mixing ratio between these two grades of coarse aggregate was adjusted to 3-5:5-8 = 1:2. Using the dry tamping method, the compacted density of the coarse aggregate was determined to be 1.75 g / cm³. 3 The coarse aggregate void ratio (VCA) is calculated based on the aggregate density. DRC The calculation result is VCA. DRC =39.8%.

[0152] S2. The initial asphalt content is set at 6.98% (i.e., an asphalt-aggregate ratio of 7.5%), the mineral powder content is 4% of the aggregate mass, the target porosity VV is 5%, and the coarse aggregate void ratio VCA is calculated based on the above. DRC =39.8%, substitute into Equations 2 and 3 to calculate the ratio of coarse to fine aggregate usage. Based on raw material test results, the compacted density γ of coarse aggregate is... s =1.75g / cm 3 apparent density γ of fine aggregate x =2.890g / cm 3 Asphalt density γ l It is 1.030 g / cm 3 mineral powder density γ k It is 2.821 g / cm³ 3 .

[0153] The coarse aggregate: fine aggregate = 65:21 is calculated by the main skeleton gap filling method.

[0154] S3, according to the gradation composition of each specification material and the calculated coarse and fine aggregate blending ratio (65:21), the amount of mineral powder is controlled to be 4%, and the synthetic gradation of mineral aggregate is obtained, as shown in Table 4:

[0155] Table 4 Synthetic gradation of mineral aggregate

[0156] Screen Pass Percentage / % 9.5 4.75 2.36 1.18 0.6 0.3 0.15 0.075 Synthetic Gradation 100 48.8 30.5 20.7 13.2 9.8 6.3 4.2

[0157] S4, the synthetic gradation is formed into a test piece, the volume index is measured, and the actual air voids of the asphalt mixture, the coarse aggregate skeleton gap rate and the asphalt film thickness are calculated accordingly. The actual air voids

[0158] = 4.8%, which meets the requirement of 3%≤ target air voids ≤6%; the coarse aggregate skeleton gap rate = 35.4%, which is less than VCA DRC (39.8%); the asphalt film thickness = 15.89 μm, which is greater than 15 μm, all meeting the design requirements.

[0159] S5, the static asphalt mixture is subjected to the Sarenburg leakage test, and the average leakage loss rate of the three parallel test results is 0.1%. The technical requirement is less than 0.3%.

[0160] S6, the road performance verification test is carried out on the static asphalt mixture, and the parallel test results of each road performance verification are:

[0161] 1) 60℃ dynamic stability is 6200 times / mm, which is greater than the technical requirement of 3000 times / mm;

[0162] 2) under the test condition of 15℃, 1000με, the four-point bending fatigue life is 823000 times, which is greater than the technical requirement of 200000 times;

[0163] 3) Kentorbury scattering loss is 3.8%, which is less than the technical requirement of 8%.

[0164] S7, the surface texture characteristics and tire vertical excitation test are carried out on the pavement test piece prepared by the static asphalt mixture, and the parallel test results are:

[0165] 1) the texture depth is 1.1mm, which is greater than the technical requirement of 0.65mm;

[0166] 2) the surface skewness S sk is -1.2mm, which meets the technical requirement of not greater than -0.8mm;

[0167] 2) the tire vertical excitation displacement is 0.8mm, which meets the technical requirement of less than 1.0mm.

[0168] All of the above tests meet the design requirements, so this synthetic gradation can be used as the final preferred gradation for this gradation design.

[0169] Example 2

[0170] The steps for designing the gradation of GT-5 silent asphalt mixture are as follows:

[0171] S1. Conventional asphalt performance and rheological properties tests were conducted on the high-viscosity and high-elasticity modified asphalt. The test results are shown in Table 5.

[0172] Table 5. Performance Test Results and Technical Requirements of High-Viscosity and High-Elasticity Modified Asphalt

[0173]

[0174] The sieving results of the diabase used in this gradation design are shown in Table 6.

[0175] Table 6 Screening Results of Mineral Materials of Various Specifications

[0176]

[0177] The compacted density of the coarse aggregate was determined to be 1.80 g / cm³ using the dry tamping method. 3 The coarse aggregate void ratio (VCA) is calculated based on the aggregate density. DRC The calculation result is VCA. DRC =39.2%.

[0178] S2. The initial asphalt content is set at 6.98% (i.e., an asphalt-aggregate ratio of 7.5%), the mineral powder content is 4% of the aggregate mass, the target porosity VV is 5%, and the coarse aggregate void ratio VCA is calculated based on the above. DRC =39.2%, substitute into Equations 2 and 3 to calculate the ratio of coarse to fine aggregate usage. Based on raw material test results, the compacted density γ of coarse aggregate is... s =1.80g / cm 3 apparent density γ of fine aggregate x =2.88g / cm 3 Asphalt density γ l It is 1.030 g / cm 3 mineral powder density γ k It is 2.71 g / cm³ 3 .

[0179] The ratio of coarse aggregate to fine aggregate was calculated to be 79:17 using the main skeleton void filling method.

[0180] S3. Based on the gradation composition of each grade of material and the calculated blending ratio of coarse and fine aggregates (79:17), the amount of mineral powder is controlled at 4%, and the composite gradation of the mineral materials is obtained, as shown in Table 7.

[0181] Table 7 Mineral aggregate synthetic gradation

[0182] Screen Pass Percentage / % 9.5 4.75 2.36 1.18 0.6 0.3 0.15 0.075 Synthetic Gradation 100 87.1 31.6 18.2 13.1 7.1 5.3 4.2

[0183] S4, the volume index of the test piece formed according to the synthetic gradation is determined, and the actual air voids, coarse aggregate skeleton voids and asphalt film thickness of the asphalt mixture are calculated accordingly. The actual air voids are finally calculated to be

[0184] = 4.5%, which meets the technical requirement of 3%≤target air voids≤6%; the coarse aggregate skeleton voids = 36.1%, which is less than VCA DRC (39.2%); and the asphalt film thickness = 16.21 μm, which is greater than 15 μm, all of which meet the design requirements.

[0185] S5, the static noise asphalt mixture is subjected to the Schrenk bleeding test, and the average bleeding loss rate of the three parallel test results is 0.16%. The technical requirement is less than 0.3%.

[0186] S6, the road performance verification test is performed on the static noise asphalt mixture, and the parallel test results of the road performance verification are as follows:

[0187] 1) the dynamic stability at 60°C is 4200 times / mm, which is greater than the technical requirement of 3000 times / mm;

[0188] 2) the four-point bending fatigue life under the test conditions of 15°C and 1000 με is 753000 times, which is greater than the technical requirement of 200000 times;

[0189] 3) the Cantabro scattering loss is 2.3%, which is less than the technical requirement of 8%.

[0190] S7, the surface texture characteristics and tire vertical excitation test are performed on the pavement test piece prepared from the static noise asphalt mixture, and the parallel test results are as follows:

[0191] 1) the texture depth is 0.84 mm, which is greater than the technical requirement of 0.65 mm;

[0192] 2) the surface skewness S sk is -1.1 mm, which meets the technical requirement of not greater than -0.8 mm;

[0193] 2) the tire vertical excitation displacement is 0.6 mm, which meets the technical requirement of less than 1.0 mm.

[0194] The above tests all meet the design requirements at the same time, and the synthetic gradation can be used as the final selected gradation of the gradation design.

[0195] Example 3

[0196] The steps for designing the gradation of GT-3 silent asphalt mixture are as follows:

[0197] S1. Conventional asphalt performance and rheological properties tests were conducted on the high-viscosity and high-elasticity modified asphalt. The test results are shown in Table 8.

[0198] Table 8. Performance Test Results and Technical Requirements of High-Viscosity and High-Elasticity Modified Asphalt

[0199]

[0200] The sieving results of the diabase used in this gradation design are shown in Table 9.

[0201] Table 9 Screening Results of Mineral Materials of Various Specifications

[0202]

[0203] The compacted density of the coarse aggregate was determined to be 1.60 g / cm³ using the dry tamping method. 3 The coarse aggregate void ratio (VCA) is calculated based on the aggregate density. DRC The calculation result is VCA. DRC =41.42%.

[0204] S2. The initial asphalt content is set at 7.49% (i.e., an asphalt-aggregate ratio of 8.1%), the mineral powder content is 4% of the aggregate mass, the target void ratio VV is 5%, and the coarse aggregate void ratio VCA is calculated based on the above. DRC =41.42%, substitute into Equations 2 and 3 to calculate the ratio of coarse to fine aggregate. According to the raw material test results, the compacted density of coarse aggregate γs = 1.60 g / cm³. 3 apparent density γ of fine aggregate x =2.80g / cm 3 Asphalt density γ l It is 1.030 g / cm 3 mineral powder density γ k It is 2.71 g / cm³ 3 .

[0205] The ratio of coarse aggregate to fine aggregate was calculated to be 71:27 using the main skeleton void filling method.

[0206] S3. Based on the gradation composition of each grade of material and the calculated blending ratio of coarse and fine aggregates (71:21), the amount of mineral powder is controlled at 4%, and the composite gradation of the mineral materials is obtained, as shown in Table 10.

[0207] Table 10 Mineral aggregate gradation

[0208] Screen Pass Percentage / % 4.75 2.36 1.18 0.6 0.3 0.15 0.075 Synthetic Gradation 100 48.0 21.4 13.0 8.9 6.4 5.1

[0209] S4, according to the synthetic gradation molding test piece, the volume index is determined, and the actual void ratio, coarse aggregate skeleton gap ratio and asphalt film thickness of the asphalt mixture are calculated. The actual void ratio is finally calculated

[0210] = 3.5%, which meets the technical requirement of 3%≤target void ratio≤6%; the coarse aggregate skeleton gap ratio = 39.5%, which is less than VCA DRC (41.42%); the asphalt film thickness = 15.32 μm, which is greater than 15 μm, and all meet the design requirements.

[0211] S5, the Schrenk bleeding test is carried out on the mute asphalt mixture, and the average bleeding loss rate of the three parallel test results is 0.24%. It is less than the technical requirement of 0.3%.

[0212] S6, the mute asphalt mixture is subjected to road performance verification test, and the parallel test results of each road performance verification are as follows:

[0213] 1) 60℃ dynamic stability is 3500 times / mm, which is greater than the technical requirement of 3000 times / mm;

[0214] 2) under the test condition of 15℃, 1000με, the four-point bending fatigue life is 812,000 times, which is greater than the technical requirement of 200,000 times;

[0215] 3) Kentorbury scattering loss is 3.84%, which is less than the technical requirement of 8%.

[0216] S7, the surface texture characteristics and tire vertical excitation test are carried out on the mute asphalt mixture pavement test piece, and the parallel test results are as follows:

[0217] 1) the asphalt mixture structure depth is 0.75 mm, which is greater than the technical requirement of 0.65 mm;

[0218] 2) the surface skewness S sk is -0.9 mm, which meets the technical requirement of not greater than -0.8 mm;

[0219] 2) the tire vertical excitation displacement is 0.45 mm, which meets the technical requirement of less than 1.0 mm.

[0220] The above tests all meet the design requirements at the same time, and this synthetic gradation can be used as the final selected gradation of this gradation design.

[0221] Example 4

[0222] The mute asphalt mixture GT-8 gradation design process steps are as follows:

[0223] S1, the conventional asphalt performance detection and rheological property test are carried out on the high-viscosity and high-elasticity modified asphalt, and the test results are shown in Table 11:

[0224] Table 11 Performance Test Results and Technical Requirements of High-Viscosity and High-Elasticity Modified Asphalt

[0225]

[0226] The sieving results of the diabase used in this gradation design are shown in Table 12:

[0227] Table 12 Screening Results of Mineral Materials of Various Specifications

[0228]

[0229] The coarse aggregate is divided into two grades: 3-5mm and 5-8mm. The mixing ratio between these two grades of coarse aggregate was adjusted to 3-5:5-8 = 1:2. Using the dry tamping method, the compacted density of the coarse aggregate was determined to be 1.75 g / cm³. 3 The coarse aggregate void ratio (VCA) is calculated based on the aggregate density. DRC The calculation result is VCA. DRC =39.8%.

[0230] S2. The initial asphalt content is set at 6.72% (i.e., the asphalt-aggregate ratio is 7.2%), the mineral powder content is 4% of the aggregate mass, the target porosity VV is 5%, and the coarse aggregate porosity VCA is calculated based on the above. DRC =39.8%, substitute into Equations 2 and 3 to calculate the ratio of coarse to fine aggregate usage. Based on raw material test results, the compacted density γ of coarse aggregate is... s =1.75g / cm 3 apparent density γ of fine aggregate x =2.890g / cm 3 Asphalt density γ l It is 1.030 g / cm 3 mineral powder density γ k It is 2.821 g / cm³ 3 .

[0231] The ratio of coarse aggregate to fine aggregate was calculated to be 65:23 using the main skeleton void filling method.

[0232] S3. Based on the gradation composition of each grade of material and the calculated blending ratio of coarse and fine aggregates (65:23), the amount of mineral powder is controlled at 4%, and the composite gradation of the mineral materials is obtained, as shown in Table 13.

[0233] Table 13 Mineral aggregate gradation

[0234] Screen Pass Percentage / % 9.5 4.75 2.36 1.18 0.6 0.3 0.15 0.075 Synthetic Gradation 100 48.9 23.4 14.5 11.0 8.3 6.6 5.2

[0235] S4, according to the synthetic gradation forming test piece, the volume index is determined, and the actual air void of the asphalt mixture, the coarse aggregate skeleton gap rate and the asphalt film thickness are calculated. The actual air void is finally calculated

[0236] = 4.0%, which meets 3% ≤ target air void ≤ 6%; coarse aggregate skeleton gap rate = 35.2%, which is less than VCA DRC (39.8%); asphalt film thickness = 15.11 μm, which is greater than 15 μm, all of which meet the design requirements.

[0237] S5, the Schrenk bleeding test is carried out on the mute asphalt mixture, and the average bleeding loss rate of the three parallel test results is 0.1%. It is less than 0.3% of the technical requirement.

[0238] S6, the road performance verification test is carried out on the mute asphalt mixture, and the parallel test results of each road performance verification are:

[0239] 1) 60℃ dynamic stability is 6200 times / mm, which is greater than 3000 times / mm of the technical requirement;

[0240] 2) Under the test condition of 15℃, 1000με, the four-point bending fatigue life is 523000 times, which is greater than 200000 times of the technical requirement;

[0241] 3) Kentorbury scattering loss is 8.1%, which does not meet the technical requirement of less than 8%, and returns to step S2 to increase the asphalt content by 0.3% for correction.

[0242] S2, set the asphalt content to 6.98% (i.e. the oil-stone ratio is 7.5%), the mineral powder content is 4% of the mass of the mineral aggregate, the target air void VV is 5%, and the coarse aggregate: fine aggregate is 65:19, which is calculated by the main skeleton void filling method.

[0243] S3, according to the gradation composition of each specification material and the calculated coarse aggregate: fine aggregate mixing ratio (65:19), the mineral powder content is controlled to be 4%, and the mineral aggregate synthetic gradation is obtained, as shown in Table 14:

[0244] Table 14 Mineral aggregate synthetic gradation

[0245] Screen Pass Percentage / % 9.5 4.75 2.36 1.18 0.6 0.3 0.15 0.075 Synthetic Gradation 100 45.2 21.4 11.8 8.1 7.5 6.3 5.1

[0246] S4, according to the synthetic gradation forming test piece, the volume index is determined, and the actual air void of the asphalt mixture, the coarse aggregate skeleton gap rate and the asphalt film thickness are calculated. The actual air void is finally calculated

[0247] = 4.2%, which meets 3% ≤ target air void ≤ 6%; coarse aggregate skeleton gap rate = 36.8%, which is less than VCA DRC(39.8%); asphalt film thickness = 16.14 pm, greater than 15 pm, both meet the design requirements.

[0248] S5, the silent asphalt mixture is subjected to the shrenburg leakage test, and the average leakage loss rate of the three parallel test results is 0.1%. Less than 0.3% of the technical requirements.

[0249] S6, the road performance verification test is carried out on the silent asphalt mixture, and the parallel test results of each road performance verification are:

[0250] 1) 60℃ dynamic stability is 5900 times / mm, greater than 3000 times / mm of the technical requirements;

[0251] 2) Under the test condition of 15℃, 1000με, the four-point bending fatigue life is 61.2 million times, greater than 20 million times of the technical requirements;

[0252] 3) Kentorbury scattering loss is 5.1%, which meets the technical requirement of less than 8%

[0253] S7, the surface texture characteristics and tire vertical excitation test are carried out on the pavement test piece prepared by the silent asphalt mixture, and the parallel test results are:

[0254] 1) The asphalt mixture structure depth is 1.2mm, greater than 0.65mm of the technical requirements;

[0255] 2) The surface skewness S sk is -1.1mm, which meets the technical requirement of not more than -0.8mm;

[0256] 2) Tire vertical excitation displacement 0.85mm, which meets the technical requirement of less than 1.0mm.

[0257] The above tests all meet the design requirements at the same time, and the synthesis gradation can be used as the final selected gradation of this gradation design.

[0258] The asphalt mixtures designed in examples 1-4 are laid on the pavement, and the noise test is carried out on the silent asphalt pavement laid, the specific test method is shown in "Highway subgrade and pavement field test specification" (JTG 3450-2019T0986), and it is compared with the traditional GAC-13 pavement, and the results are shown in table 15:

[0259] Table 15 noise test results

[0260] Example 1 Example 2 Example 3 Example 4 GAC-1 Pavement Noise Test Results dB 71.5 69.8 65.1 72.1 75.3

[0261] Any combination of the technical features in the above-described embodiments can be made, and for the sake of brevity, not all possible combinations are described, however, as long as the combination of the technical features does not exist in contradiction, it shall be considered within the scope of the present disclosure.

[0262] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it shall not be understood as a limitation on the patent scope of the present application. It shall be pointed out that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these shall be within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A method for designing a quiet asphalt mixture, wherein the asphalt mixture comprises asphalt and mineral aggregates, the mineral aggregates comprising coarse aggregates, fine aggregates and mineral powder, characterized in that, The method comprises the following steps: S1. Determine the VCA of the coarse aggregate according to the blending ratio of each grade in the coarse aggregate DRC ; S2, taking the aggregate with a particle size of 0-2.36 mm as fine aggregate, determining the ratio of the amount of coarse aggregate to the amount of fine aggregate according to the amount of asphalt, the amount of mineral powder, the target void ratio and the skeleton gap ratio of the coarse aggregate in step S1 by using the main skeleton gap filling method; S3, synthesizing the aggregate gradation according to the ratio of the amount of coarse aggregate to the amount of fine aggregate in step S2 and the gradation combination of the coarse aggregate, the fine aggregate and the mineral powder; S4, preparing asphalt mixture according to the mineral aggregate gradation obtained in step S3, determining the actual air voids, coarse aggregate voids, and asphalt film thickness in the asphalt mixture, and if qualified, entering the next step of testing, or if unqualified, returning to step S1 or step S2 for correction; the judgment standard for the actual air voids in the asphalt mixture is 3%≤target air voids≤6%, the judgment standard for the qualified coarse aggregate voids is ≤VCA DRC , and the judgment standard for the qualified asphalt film thickness is ≥15μm; S5, determining the bleeding loss rate of the qualified asphalt mixture obtained in step S4, and if the asphalt mixture is qualified, the next step is performed, otherwise, the step S2 is returned to correct; S6, performing the road performance test on the qualified asphalt mixture obtained in step S5, and if the asphalt mixture is qualified, the next step is performed, otherwise, the step S1 or the step S2 is returned to correct; S7, performing the surface texture feature and tire vertical excitation test on the road test piece prepared from the qualified asphalt mixture obtained in step S6, and if the road test piece is qualified, the synthesized aggregate gradation and the amount of asphalt are taken as the final ratio of the quiet asphalt mixture design, otherwise, the step S1 or the step S2 is returned to correct.

2. A method of designing a quiet asphalt mixture according to claim 1, characterized in that: The performance requirements of the asphalt are as follows: the complex shear modulus G* at 60℃ is greater than 12 kPa, the dynamic viscosity at 60℃ is greater than 580,000 Pa·s, and the elastic recovery at 25℃ is greater than 98%.

3. The method for designing the quiet asphalt mixture according to claim 1, wherein: The method for determining the skeleton gap ratio of the coarse aggregate in step S1 comprises: testing the close-packed density of the coarse aggregate by using the dry ramming method, and calculating the skeleton gap ratio of the coarse aggregate according to formula 1, In formula 1, VCA DRC is the apparent density of the coarse aggregate, g / cm CA 3 ; γ s is the apparent density of the coarse aggregate, g / cm 3 ;​ The amount of asphalt in step S2 is determined by the oil-stone ratio, the oil-stone ratio is 7.2-8.5%, the amount of mineral powder is 2-6% of the mass of the aggregate, and the target void ratio is 3-6%; The method for determining the ratio of the amount of coarse aggregate to the amount of fine aggregate by using the main skeleton gap filling method in step S3 comprises: the sum of the volume of the fine aggregate, the volume of the mineral powder, the volume of the asphalt and the target void volume of the asphalt mixture is equal to the void volume of the coarse skeleton, so as to obtain the ratio of the amount of coarse aggregate to the amount of fine aggregate, and the calculation process satisfies formula 2 and formula 3 equations: p c +p x +p k = 100 Equation 2; In Equations 2 and 3: p c p x p k p l These represent the percentages (%) of coarse aggregate, fine aggregate, mineral powder, and bitumen in the aggregate composition; VCA DRC VV is the skeleton void ratio of coarse aggregate, %; VV is the target void ratio, %; γ x γ k Apparent densities of fine aggregate and mineral powder, respectively, in g / cm³. 3 ;γ l The density of asphalt, in g / cm³ 3 ;γ s The compacted density of the coarse aggregate skeleton, in g / cm³ 3 .

4. A method of designing a quiet asphalt mixture as claimed in claim 1, wherein: Before step S4 is performed, the aggregate gradation synthesized in step S3 needs to be verified, and if the aggregate gradation is qualified, the step S4 is performed, otherwise, the step S2 is returned to correct; The judgment standard for the qualified aggregate gradation is as follows:

5. The method of designing a quiet asphalt mixture as claimed in claim 1, wherein: In step S4, when the coarse aggregate gap ratio of the asphalt mixture is unqualified, the step S1 is returned to increase the blending ratio of the larger particle size range in the coarse aggregate, or the step S2 is returned to reduce the amount of mineral powder; when the asphalt film thickness is unqualified, the step S2 is returned to increase the amount of asphalt.

6. The method of designing a quiet asphalt mixture as claimed in claim 1, wherein, In step S6, the judgment standard for the qualified asphalt mixture is that the asphalt mixture should meet the following road performances at the same time: 1) the dynamic stability of the wheel tracking test at 60℃ is not less than 3,000 times / mm; 2) the four-point bending fatigue life under the test condition of 15℃ and 1,000με is not less than 2,000,000 times; 3) the Kentucky flying loss is not greater than 8%.

7. A method of designing a quiet asphalt mixture as claimed in claim 1, wherein: The judgment standard for eligibility in step S7 is that the surface texture characteristics of the road test piece prepared by the asphalt mixture have a texture depth > 0.65 mm, a surface skewness S sk ≤ -0.8 mm, and a tire vertical excitation displacement < 1.0 mm.

8. A method of designing a quiet asphalt mixture as claimed in claim 1, wherein: In step S7, when either the construction depth or the surface skewness degree does not meet the requirement, return to step S1 to increase the mixing proportion of the larger particle grade in the coarse aggregate, or return to step S2 to reduce the amount of mineral powder; when the vertical excitation displacement of the tire does not meet the requirement, return to step S1 to reduce the mixing proportion of the larger particle grade in the coarse aggregate, or return to step S2 to increase the amount of asphalt.

9. The method of designing a quiet asphalt mixture as claimed in claim 1, wherein: The vertical excitation of the tire is obtained by three-dimensional modeling and finite element software simulation test, wherein the Yeoh constitutive model is selected as the rubber model of the tire. The method comprises the following steps: S7.1, a high-precision line laser scanner is used to scan the surface construction of a rut plate test piece made of asphalt mixture, and surface construction elevation point cloud matrix data is obtained; S7.2, overlapping data in the surface construction elevation point cloud matrix data is removed, the data is denoised, de-skewed and zeroed, a three-dimensional pavement is established in the Abaqus finite element software, and Prony series is used to represent the viscoelastic properties of the pavement; S7.3, a three-dimensional tire model is established in the finite element software, wherein the tire body, the tread and the sidewall are included, and the Yeoh constitutive model is selected as the rubber model of the tire; S7.4, the Interaction module is defined and set to set the tread and the three-dimensional pavement as surface-to-surface contact, the contact surface is set as a contact mode with a fixed friction coefficient, and the friction coefficient is set; S7.5, the tire is moved downward to achieve initial contact with the pavement, the downward constraint of the tire is released, the tire bounces on the pavement, but is still in contact; S7.6, a concentrated force is applied to simulate that the tire receives the load of a car; S7.7, the speed and angular velocity of the tire are applied to simulate that the tire rolls on the pavement; S7.8, the test time of the center point of the tire is set so that the travel of the tire during the test time covers the length of the entire three-dimensional pavement, the displacement data of the center point of the tire is extracted after the test is completed, and the vertical excitation displacement of the tire is the height difference between the highest point and the lowest point of the center point of the tire along the vertical direction during the entire travel.

10. A quiet asphalt mixture characterized by: The asphalt mixture has a porosity of 3-6%, and a maximum nominal particle size of 3-8 mm; the pavement test piece prepared therefrom has a construction depth > 0.65 mm, and a surface skewness S sk ≤ -0.8 mm.

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