Asphalt mixture and preparation method thereof

Abstract

The invention discloses an asphalt mixture which comprises the following components in parts by mass: 0-5 parts of mineral powder; 0.8-6 parts by mass of a polymerized polyisocyanate solid; 80-96 parts by mass of aggregate and 4-5 parts by mass of asphalt. The polymerized polyisocyanate solid has the advantages of low density, high wettability and the like, also has certain strength, good high temperature resistance and corrosion resistance, and has excellent compatibility with asphalt. The polymerized polyisocyanate solid is added into the asphalt mixture and partially replaces mineral powder and fine aggregate in a conventional asphalt mixture, so that on one hand, the consumption of natural aggregate is reduced, the production cost is reduced, and the environmental pollution and carbon emission are reduced; and on the other hand, the lightweight of the asphalt mixture is realized, the pavement performance is considered, the high temperature resistance and rutting resistance of the asphalt mixture are improved, and the asphalt mixture has remarkable economic benefits, social benefits and environmental benefits.

Description

Technical Field

[0001] This invention relates to the field of road engineering, specifically to an asphalt mixture containing polymeric polyisocyanate solids. The invention also relates to a method for preparing the asphalt mixture. Background Technology

[0002] Asphalt mixtures are generally composed of aggregates and asphalt, and are obtained through a certain production process under certain temperature conditions. The aggregates mainly consist of coarse aggregates, fine aggregates, and fillers.

[0003] Filler and fine aggregate play crucial roles in asphalt mixtures. Fine aggregate is an essential component of the aggregate skeleton structure in asphalt mixtures, while filler not only fills the voids in the aggregate skeleton, creating conditions for contact between aggregates, but also forms a high-viscosity asphalt-filler mastic with the asphalt. Filler and fine aggregate significantly influence the high-temperature rutting resistance, low-temperature cracking resistance, and water stability of asphalt mixtures. The amount of filler and fine aggregate used in asphalt mixtures is substantial; approximately 500 tons of filler and over 1000 tons of fine aggregate are consumed for every kilometer of asphalt road. With national restrictions on the mining of natural sand and gravel, natural mineral resources are becoming increasingly scarce.

[0004] At the same time, the concept of "zero-waste city" focuses on bulk industrial solid waste, agricultural waste, construction waste, and domestic waste to achieve resource utilization and safe disposal of solid waste.

[0005] Polymeric polyisocyanate solids are byproducts of the industrial production of organic polyisocyanates. At room temperature, they are brownish-red porous granular solids with a density only 1 / 3 to 1 / 2 that of natural stone. Currently, the disposal of polymeric polyisocyanate solids mostly involves landfilling or incineration, resulting in significant resource waste and environmental pollution. Therefore, it is necessary to find more environmentally friendly and higher value-added reuse methods. Summary of the Invention

[0006] The present invention provides a mineral composition for asphalt mixtures, comprising: 0-5 parts by weight of mineral powder; 0.8-6 parts by weight of polymeric polyisocyanate solids; and 80-96 parts by weight of aggregates.

[0007] The present invention also provides an asphalt mixture comprising: 0-5 parts by weight of mineral powder; 0.8-6 parts by weight of polymeric polyisocyanate solids; 80-96 parts by weight of aggregates and 4-5 parts by weight of asphalt.

[0008] The present invention also provides a method for preparing the asphalt mixture, comprising the following steps:

[0009] (1) Stir the aggregate at 165-175℃ to obtain mixture A;

[0010] (2) Heat the asphalt to 160-170℃ and mix it with the mixture A and stir to obtain mixture B;

[0011] (3) Heat the mineral powder and the polymeric polyisocyanate solid to 165-175°C, then mix them with the mixture B and stir. Remove the mixture from the pot at 160-170°C. Detailed Implementation

[0012] General definitions and terms

[0013] Unless otherwise stated, all publications, patent applications, patents and other references mentioned herein are incorporated herein in their entirety by way of citation.

[0014] 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 invention pertains. In case of any conflict, the definitions provided herein shall prevail.

[0015] Unless otherwise stated, all percentages, parts, proportions, etc., are by weight. Those skilled in the art will understand that the sum of all components in a composition may suitably be 100%. When quantities, concentrations, or other values ​​or parameters are given as ranges, preferred ranges, or preferred upper and lower limits, or specific values, they should be understood as specifically disclosing all ranges formed by paired values ​​of any upper or preferred range and any lower or preferred range, regardless of whether the range is disclosed individually. Unless otherwise stated, when numerical ranges are referred to herein, the range means including its endpoints and all integers and fractions within that range.

[0016] When used with a numerical variable, the terms "about" or "approximately" usually mean that the value of the variable and all values ​​of the variable are within the experimental error (e.g., within a 95% confidence interval for the mean) or within ±10% of the specified value, or a wider range.

[0017] As used herein, the terms “optional” or “optionally” mean that an event or situation described below may or may not occur. This description includes both the occurrence and non-occurrence of the event or situation, as well as any arbitrary selection of the content described below. For example, when the content of a certain ingredient in this document is 0%-5%, it means that the component may be optionally present, i.e., it covers the cases of its absence (0%) and its presence (>0-5%).

[0018] The terms “comprising,” “including,” “having,” “containing,” or “involving,” and their other variations herein, are inclusive or open-ended and do not exclude other unlisted elements or method steps. Those skilled in the art will understand that the foregoing terms such as “comprising” encompass the meaning of “consisting of.” The expression “consisting of” excludes any unspecified elements, steps, or ingredients. The expression “substantially constitutes” limits the scope to the specified elements, steps, or ingredients, plus optional elements, steps, or ingredients that do not materially affect the essential and novel features of the claimed subject matter. It should be understood that the expression “comprising” encompasses both the expressions “substantially constitutes” and “consisting of.” The term “selected from” refers to one or more elements from the group listed below, selected independently, and may include combinations of two or more of these elements.

[0019] As used herein, the terms “one or more” or “at least one” refer to one, two, three, four, five, six, seven, eight, nine or more.

[0020] As used herein, the term "and / or" encompasses both "and" and "or". Multiple elements, components, or steps defined by "and / or" represent any one of those elements, components, or steps and any combination thereof. For example, A and / or B encompasses A, B, and A+B; A, B, and / or C encompasses A, B, C, A+B, A+C, B+C, and A+B+C.

[0021] Unless otherwise stated, the terms "combinations thereof", "any combination thereof" and "mixtures thereof" refer to multi-component mixtures of the elements, such as two, three, four, and up to the maximum possible multi-component mixtures.

[0022] Furthermore, if the number of components or parts of the present invention is not previously specified, it indicates that there is no limitation on the number of times a component or part may appear (or be present). Therefore, it should be interpreted as including one or at least one, and the singular form of a component or part also includes the plural, unless the value clearly indicates a singular number.

[0023] In this article, "multiple" or "several" means two or more, without specifying which ones unless otherwise explicitly defined. Unless the context clearly indicates otherwise, "one" can encompass both singular and plural references.

[0024] The present invention provides a mineral composition for asphalt mixtures, comprising: 0-5 parts by weight of mineral powder; 0.8-6 parts by weight of polymeric polyisocyanate solids; and 80-96 parts by weight of aggregates.

[0025] The present invention also provides an asphalt mixture comprising: 0-5 parts by weight of mineral powder; 0.8-6 parts by weight of polymeric polyisocyanate solids; 80-96 parts by weight of aggregates and 4-5 parts by weight of asphalt.

[0026] In this invention, the polymeric polyisocyanate solid is a byproduct generated during the production of organic polyisocyanates, including polymers of one or more organic polyisocyanates. The polymeric polyisocyanate in this invention can be an aromatic polyisocyanate, such as a byproduct generated during the production of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), hexamethylene diisocyanate (HDI), terephthalic diisocyanate (PPDI), or terephthalic diisocyanate (XDI).

[0027] In one embodiment of the present invention, the polymeric polyisocyanate solid is a solid byproduct generated during the production of toluene diisocyanate (TDI), preferably polymeric toluene diisocyanate, or a polymer of toluene diisocyanate (pTDI), and more preferably polymeric toluene diisocyanate solid generated by producing toluene diisocyanate using the gas phase phosgene method.

[0028] In one embodiment of the present invention, the solid polymerized toluene diisocyanate has a Mohs hardness of 2-4.

[0029] In one embodiment of the present invention, the solid ash content of the polymeric toluene diisocyanate is less than 0.5% by weight.

[0030] In one embodiment of the present invention, the polymeric toluene diisocyanate solid is insoluble in water at room temperature and atmospheric pressure, and has a solubility of less than 5% by weight in acetone, chlorobenzene, dimethylformamide, dimethyl sulfoxide, dimethylacetamide, carbon disulfide, chloroform, dichloromethane, tetrahydrofuran, and xylene.

[0031] In one embodiment of the present invention, the content of reactive isocyanate groups NCO in the polymerized toluene diisocyanate solid is less than 6% by weight.

[0032] In the mineral composition or asphalt mixture of the present invention, the particle size range of the polymeric polyisocyanate solid can be less than 0.3 mm, or 0.001 mm to 0.3 mm. The particle size range can be obtained by grinding the polymeric polyisocyanate solid using conventional grinding methods. The optional methods are: (1) grinding the polymeric polyisocyanate solid in a grinding mill at a speed of 1000-3000 r / min for more than 5 minutes to obtain polymeric polyisocyanate solid crushed material; (2) sieving the polymeric polyisocyanate solid crushed material with a sieve aperture size of 0.3 mm.

[0033] In one embodiment of the present invention, the screening is carried out in a shaking screen machine, and the screening time is more than 3 minutes.

[0034] In one embodiment of the present invention, the particle size distribution range of the polymeric polyisocyanate solid includes (1) a particle size less than 0.075 mm, preferably 0.001 mm or more and less than 0.075 mm; and / or (2) a particle size of 0.075 mm or more and less than 0.15 mm; and / or (3) a particle size of 0.15 mm to 0.3 mm. The particle size distribution can be obtained by grinding and sieving the polymeric polyisocyanate solid using conventional grinding methods.

[0035] In one embodiment of the present invention, the particle size of the polymeric polyisocyanate solid is preferably less than 0.075 mm, more preferably 0.001 mm or more and less than 0.075 mm.

[0036] In one embodiment of the present invention, the aggregate composition for asphalt mixture comprises 0-5 parts by weight of mineral powder; 0.4-2.4 parts by weight of polymeric polyisocyanate solids with a particle size less than 0.075 mm; 0.8-2 parts by weight of polymeric polyisocyanate solids with a particle size of 0.075 mm or more and less than 0.15 mm; 0.8-2 parts by weight of polymeric polyisocyanate solids with a particle size of 0.15 mm to 0.3 mm; and 80-96 parts by weight of aggregate.

[0037] In one embodiment of the present invention, the aggregate composition for asphalt mixture comprises 0-5 parts by weight of mineral powder; 0.8-6 parts by weight of polymeric polyisocyanate solids with a particle size of less than 0.075 mm; and 80-96 parts by weight of aggregate.

[0038] In one embodiment of the present invention, the asphalt mixture comprises 0-5 parts by weight of mineral powder; 0.4-2.4 parts by weight of polymeric polyisocyanate solids with a particle size less than 0.075 mm; 0.8-2 parts by weight of polymeric polyisocyanate solids with a particle size greater than 0.075 mm and less than 0.15 mm; 0.8-2 parts by weight of polymeric polyisocyanate solids with a particle size of 0.15 mm to 0.3 mm; 80-96 parts by weight of aggregate; and 4-5 parts by weight of asphalt.

[0039] In the mineral composition or asphalt mixture of the present invention, the mineral powder may be limestone powder. The particle size range of the mineral powder may be less than 0.075 mm, or greater than 0.001 mm and less than 0.075 mm. This particle size range can be obtained by conventional grinding methods.

[0040] In the mineral composition or asphalt mixture of the present invention, the amount of mineral powder is 0-5 parts by weight, preferably 2-5 parts by weight.

[0041] In the mineral composition or asphalt mixture of the present invention, the aggregate may be basalt aggregate. In one embodiment of the present invention, the aggregate includes:

[0042] 4-6 parts by weight of aggregate with a particle size range greater than 13.2 mm and less than 16 mm; 16-20 parts by weight of aggregate with a particle size range greater than 9.5 mm and less than 13.2 mm; 22-25 parts by weight of aggregate with a particle size range greater than 4.75 mm and less than 9.5 mm; 15-17 parts by weight of aggregate with a particle size range greater than 2.36 mm and less than 4.75 mm; 10-12 parts by weight of aggregate with a particle size range greater than 1.18 mm and less than 2... Aggregates smaller than 0.36 mm; 6-8 parts by weight of aggregates with a particle size range greater than 0.6 mm and less than 1.18 mm; 3-7 parts by weight of aggregates with a particle size range greater than 0.3 mm and less than 0.6 mm; 0-4 parts by weight (preferably 1-4 parts by weight) of aggregates with a particle size range of 0.15 mm to 0.3 mm; 0-6 parts by weight (preferably 1-6 parts by weight) of aggregates with a particle size range of 0.075 mm and less than 0.15 mm.

[0043] In this invention, the asphalt can be selected from various specifications of base asphalt in the art, including 70# asphalt and / or 90# asphalt.

[0044] The present invention also provides a method for preparing the asphalt mixture, comprising the following steps:

[0045] (1) Stir the aggregate at 165-175℃ to obtain mixture A;

[0046] (2) Heat the asphalt to 160-170℃ and mix it with the mixture A and stir to obtain mixture B;

[0047] (3) Heat the mineral powder and the polymeric polyisocyanate solid to 165-175°C, then mix them with the mixture B and stir. Remove the mixture from the pot at 160-170°C.

[0048] The stirring time in steps (1), (2) or (3) can be 80-90 seconds.

[0049] Preferably, the aggregates, mineral powders and polymeric polyisocyanate solids are dried before preparation, for example, by heating and drying at 100°C for more than 6 hours.

[0050] The stirring can be carried out in various stirring devices, such as mixing pots.

[0051] Beneficial effects

[0052] (1) The inventors of this invention have discovered that solid polymeric polyisocyanate has advantages such as low density and high wettability, as well as certain strength, good high temperature resistance and corrosion resistance, and excellent compatibility with asphalt.

[0053] (2) The asphalt mixture of the present invention incorporates polymeric polyisocyanate solids, which partially replaces the mineral powder and fine aggregates in conventional asphalt mixtures. On the one hand, it reduces the consumption of natural aggregates, reduces the environmental and energy problems caused by burning and landfilling polymeric polyisocyanate solids, reduces production costs, and reduces environmental pollution and carbon emissions. On the other hand, it reduces the density of the asphalt mixture, realizes the lightweighting of the asphalt mixture, and improves the high temperature resistance and rutting resistance of the asphalt mixture while taking into account the road performance. It has significant economic, social and environmental benefits.

[0054] (3) The preparation method of the present invention is simple in process, which helps to reduce costs and is suitable for large-scale industrial production.

[0055] Example

[0056] The present invention will be further illustrated below with reference to specific embodiments. However, it should be understood that these embodiments are for illustrative purposes only and do not constitute a limitation on the scope of the invention.

[0057] Test methods in the following examples, unless otherwise specified, are generally performed under standard conditions or as recommended by the manufacturer. Unless otherwise stated, all percentages and parts are by weight.

[0058] Example 1:

[0059] The asphalt mixture is composed of the following components in parts by weight: 4 parts mineral powder, 0.8 parts polymeric polyisocyanate, 94 parts aggregate, and 4.5 parts 70# asphalt.

[0060] The mineral powder is limestone powder with a particle size range of less than 0.075 mm.

[0061] The polymeric polyisocyanate solid is a powder after being crushed and sieved, with a particle size range of less than 0.075 mm.

[0062] The aggregate is basalt powder. Of the 94 parts by weight of aggregate, by particle size, 5 parts by weight are aggregates with a particle size range greater than 13.2 mm and less than 16 mm; 18.5 parts by weight are aggregates with a particle size range greater than 9.5 mm and less than 13.2 mm; 23.5 parts by weight are aggregates with a particle size range greater than 4.75 mm and less than 9.5 mm; 16 parts by weight are aggregates with a particle size range greater than 2.36 mm and less than 4.75 mm; 10.5 parts by weight are aggregates with a particle size range greater than 1.18 mm and less than 2.36 mm; 7.5 parts by weight are aggregates with a particle size range greater than 0.6 mm and less than 1.18 mm; 5.5 parts by weight are aggregates with a particle size range greater than 0.3 mm and less than 0.6 mm; 3.5 parts by weight are aggregates with a particle size range between 0.15 mm and 0.3 mm; and 4 parts by weight are aggregates with a particle size range greater than 0.075 mm and less than 0.15 mm.

[0063] The asphalt mixture is prepared by the following method:

[0064] (1) Weigh the aggregate heated to 170°C according to the proportion and add it to the mixing pot. Stir for 90 seconds to obtain mixture A.

[0065] (2) Heat the asphalt to 165°C and put it into a mixing pot together with mixture A, stir for 90 seconds to obtain mixture B;

[0066] (3) Heat the mineral powder and solid polyisocyanate to 170°C and then put them together with mixture B into a mixing pot. Stir for 90 seconds and then remove from the pot at 165°C.

[0067] Example 2:

[0068] The asphalt mixture is composed of the following components in parts by weight: 2 parts mineral powder, 1.6 parts polymeric polyisocyanate solids, 94 parts aggregate, and 4.5 parts 70# asphalt.

[0069] The other components and preparation methods are the same as in Example 1.

[0070] Example 3:

[0071] The asphalt mixture is composed of the following components in parts by weight: 2.4 parts of polymeric polyisocyanate solids, 94 parts of aggregates, and 4.5 parts of 70# asphalt.

[0072] The other components and preparation methods are the same as in Example 1.

[0073] Example 4:

[0074] The asphalt mixture is composed of the following components in parts by weight: mineral powder: 3 parts, polymeric polyisocyanate solids with a particle size less than 0.075 mm: 1.2 parts, polymeric polyisocyanate solid fine aggregate: 1.6 parts, aggregate: 90 parts, and 70# asphalt: 4.5 parts.

[0075] The mineral powder is limestone powder with a particle size range of less than 0.075 mm.

[0076] The polymeric polyisocyanate solid fine aggregate is polymeric polyisocyanate solid after crushing and screening, with a particle size range greater than 0.075 mm and less than 0.3 mm. The mass ratio of polymeric polyisocyanate solid fine aggregate with a particle size range greater than 0.075 mm and less than 0.15 mm to polymeric polyisocyanate solid fine aggregate with a particle size range greater than 0.15 mm and less than 0.3 mm is 1:1.

[0077] The aggregate is basalt. Of the 90 parts by weight of aggregate, by particle size, 5 parts by weight are aggregates with a particle size range greater than 13.2 mm and less than 16 mm; 18.5 parts by weight are aggregates with a particle size range greater than 9.5 mm and less than 13.2 mm; 23.5 parts by weight are aggregates with a particle size range greater than 4.75 mm and less than 9.5 mm; 16 parts by weight are aggregates with a particle size range greater than 2.36 mm and less than 4.75 mm; 10.5 parts by weight are aggregates with a particle size range greater than 1.18 mm and less than 2.36 mm; 7.5 parts by weight are aggregates with a particle size range greater than 0.6 mm and less than 1.18 mm; 5.5 parts by weight are aggregates with a particle size range greater than 0.3 mm and less than 0.6 mm; 1.5 parts by weight are aggregates with a particle size range between 0.15 mm and 0.3 mm; and 2 parts by weight are aggregates with a particle size range greater than 0.075 mm and less than 0.15 mm.

[0078] The asphalt mixture is prepared by the following method:

[0079] (1) Weigh the aggregate heated to 170°C according to the proportion and add it to the mixing pot. Stir for 90 seconds to obtain mixture A.

[0080] (2) Heat the base asphalt to 165°C and put it into a mixing pot together with mixture A, stir for 90 seconds to obtain mixture B;

[0081] (3) Heat the mineral powder, solid polyisocyanate with a particle size of less than 0.075 mm, and fine aggregate of solid polyisocyanate to 170°C and put them together with mixture B into a mixing pot. Stir for 90 seconds and then remove from the pot at 165°C.

[0082] Example 5:

[0083] The asphalt mixture is composed of the following components in parts by weight: mineral powder: 1.5 parts, polymeric polyisocyanate solids with a particle size less than 0.075 mm: 1.8 parts, polymeric polyisocyanate solid fine aggregate: 2.2 parts, aggregate: 88.5 parts, and base asphalt: 4.5 parts.

[0084] The mass ratio of polymeric polyisocyanate solid fine aggregate with a particle size range of greater than 0.075 mm and less than 0.15 mm to polymeric polyisocyanate solid fine aggregate with a particle size range of greater than 0.15 mm and less than 0.3 mm is 3:2.5.

[0085] Of the aggregates, 1 part by weight consists of aggregates with a particle size range of 0.15 mm to 0.3 mm; 1 part by weight consists of aggregates with a particle size range of 0.075 mm or larger and smaller than 0.15 mm; the rest is the same as in Example 4.

[0086] The other components and preparation methods are the same as in Example 4.

[0087] Example 6:

[0088] The asphalt mixture is composed of the following components in parts by weight: 2.4 parts of polymeric polyisocyanate solids with a particle size less than 0.075 mm, 2.8 parts of polymeric polyisocyanate solid fine aggregates, 87 parts of aggregates, and 4.5 parts of base asphalt.

[0089] The mass ratio of polymeric polyisocyanate solid fine aggregate with a particle size range of greater than 0.075 mm and less than 0.15 mm to polymeric polyisocyanate solid fine aggregate with a particle size range of greater than 0.15 mm and less than 0.3 mm is 1:1.

[0090] Of the aggregates, 0.5 parts by weight are aggregates with a particle size range greater than 0.075 mm and less than 0.15 mm, and the rest is the same as in Example 4.

[0091] The other components and preparation methods are the same as in Example 1.

[0092] Comparative Example 1:

[0093] The asphalt mixture is composed of the following components in parts by weight: 6 parts mineral powder, 94 parts aggregate, and 4.5 parts base asphalt.

[0094] The other components and preparation methods are the same as in Example 1.

[0095] Asphalt mixtures prepared in Examples 1-6 and Comparative Example 1 were subjected to Marshall stability tests according to the method specified in the specification "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011) (T 0709); freeze-thaw splitting tests according to the method specified in the specification "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011) (T 0729); rutting tests according to the method specified in the specification "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011) (T 0719); and semi-circular bending tests according to the method specified in the specification "Determining the Fracture Energy of Asphalt Mixtures Using the Semi-ircular Bend Geometry (SCB) AASHTO Designation: TP 105-13". The test results are shown in Table 1.

[0096] In summary, this invention, through the combination of mineral powder, urea isocyanate, aggregates, and asphalt, improves the rutting resistance of asphalt mixtures by 60%, exhibits strong high-temperature stability, and can be applied to roads with high temperatures and heavy loads, including highways, municipal roads, bridge decks, tunnels, and normal road sections. Simultaneously, the asphalt mixture of this invention is lightweight, allowing it to directly replace the middle and lower layers in bridge pavement structures, demonstrating excellent performance and effectively achieving lightweight bridge pavement. This invention offers advantages in resource and cost savings, being 5-10% cheaper than similar materials and reducing natural stone usage by 10%-15% compared to similar products. Furthermore, this invention saves energy consumption such as machinery and fuel in raw material production, transportation, and mixture heating and transportation, directly reducing carbon emissions by 10-20% and pollution by 10-20%. It simultaneously solves the problems of resource utilization of urea isocyanate, performance enhancement of pavement materials, and conservation of mineral resources in road engineering.

[0097]

Claims

1. A mineral aggregate composition for asphalt mixtures, characterized in that, It includes 0-5 parts by weight of mineral powder; and 0.8-6 parts by weight of polymeric polyisocyanate solids. Mixed with 80-96 parts by weight of aggregate.

2. An asphalt mixture, characterized in that, It includes: 0-5 parts by weight of mineral powder; 0.8-6 parts by weight of polymeric polyisocyanate solids; 80-96 parts by weight of aggregate and 4-5 parts by weight of asphalt.

3. The asphalt mixture as described in claim 2, characterized in that, The polymeric polyisocyanate solid is polymeric toluene diisocyanate, preferably polymeric toluene diisocyanate solid produced by the gas-phase phosgene process for producing toluene diisocyanate.

4. The asphalt mixture as described in claim 2 or 3, characterized in that, The solid polymerized toluene diisocyanate has a Mohs hardness of 2-4; and / or the content of reactive isocyanate groups (NCO) in the solid polymerized toluene diisocyanate is less than 6% by weight.

5. The asphalt mixture according to any one of claims 2-4, characterized in that, The particle size range of the polymeric polyisocyanate solid is less than 0.3 mm, preferably including the following particle size distribution: (1) particle size less than 0.075 mm; and / or (2) particle size greater than or equal to 0.075 mm and less than 0.15 mm; and / or (3) particle size from 0.15 mm to 0.3 mm; more preferably, the particle size range is less than 0.075 mm.

6. The asphalt mixture according to any one of claims 2-5, characterized in that: The asphalt mixture comprises 0-5 parts by weight of mineral powder; 0.4-2.4 parts by weight of polymeric polyisocyanate solids with a particle size less than 0.075 mm; 0.8-2 parts by weight of polymeric polyisocyanate solids with a particle size greater than 0.075 mm and less than 0.15 mm; 0.8-2 parts by weight of polymeric polyisocyanate solids with a particle size of 0.15 mm to 0.3 mm; 80-96 parts by weight of aggregate; and 4-5 parts by weight of asphalt.

7. The asphalt mixture according to any one of claims 2-6, characterized in that, The mineral powder is limestone mineral powder; and / or, the particle size range of the mineral powder is less than 0.075 mm; and / or, the amount of the mineral powder used is 2-5 parts by weight.

8. The asphalt mixture according to any one of claims 2-7, characterized in that, The aggregate is basalt aggregate; and / or, the aggregate comprises: 4-6 parts by weight of aggregate with a particle size range greater than 13.2 mm and less than 16 mm; 16-20 parts by weight of aggregate with a particle size range greater than 9.5 mm and less than 13.2 mm; 22-25 parts by weight of aggregate with a particle size range greater than 4.75 mm and less than 9.5 mm; 15-17 parts by weight of aggregate with a particle size range greater than 2.36 mm and less than 4.75 mm; 10 -12 parts by weight of aggregate with a particle size range greater than 1.18 mm and less than 2.36 mm; 6-8 parts by weight of aggregate with a particle size range greater than 0.6 mm and less than 1.18 mm; 3-7 parts by weight of aggregate with a particle size range greater than 0.3 mm and less than 0.6 mm; 0-4 parts by weight of aggregate with a particle size range between 0.15 mm and 0.3 mm; 0-6 parts by weight of aggregate with a particle size range greater than 0.075 mm and less than 0.15 mm.

9. The asphalt mixture according to any one of claims 2-8, characterized in that, The asphalt mentioned includes 70# asphalt and / or 90# asphalt.

10. A method for preparing an asphalt mixture as described in any one of claims 2-9, comprising the following steps: (1) Stir the aggregate at 165-175℃ to obtain mixture A; (2) Heat the asphalt to 160-170℃ and mix it with the mixture A and stir to obtain mixture B; (3) Heat the mineral powder and the polymeric polyisocyanate solid to 165-175°C and mix them with the mixture B and stir. Remove the mixture from the pot at 160-170°C. The stirring time in steps (1), (2) or (3) is preferably 80-90 seconds. And / or, the aggregate, mineral powder and polymeric polyisocyanate solid are preferably dried before preparation.

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