A polyurethane mixture capable of promoting curing and a preparation method thereof

Abstract

The present invention provides a polyurethane mixture capable of promoting curing and a preparation method thereof. The polyurethane mixture comprises the following components: graded aggregate, polyurethane, and a composite curing material, wherein a curing agent is present inside the composite curing material; wherein, based on the total mass of the polyurethane mixture, the content of the composite curing material is more than 0.1%, preferably 0.1% - 5%. The polyurethane mixture of the present invention contains a composite curing material. By using the composite curing material, the curing degree of the polyurethane mixture can be improved, so that the polyurethane mixture obtains better road performance. The preparation method of the polyurethane mixture of the present invention is simple and easy to implement, the raw materials are easy to obtain, and it is suitable for mass production.

Description

Technical Field

[0001] The present invention relates to a polyurethane mixture capable of promoting curing and a preparation method thereof, belonging to the field of new materials and their applications. Background Art

[0002] Due to advantages such as good flatness, comfortable driving, and low noise, asphalt pavement has become the most widely used pavement form at present, and asphalt has also become the most important pavement binder material. As a product of petroleum refining, asphalt has strong temperature sensitivity, being prone to cracking at low temperatures in winter and softening at high temperatures in summer. In order to overcome the temperature sensitivity in the use of asphalt, polymers are usually used to modify asphalt. Polymers include ethylene-vinyl acetate copolymer (EVA), styrene-butadiene-styrene (SBS), polyethylene (PE), polypropylene (PP), natural rubber (NR), polyurethane (PU), etc.

[0003] Through polymer modification, the low-temperature crack resistance and high-temperature stability of asphalt materials are effectively improved. However, during the asphalt modification process, first, it is necessary to heat asphalt and the modifier, increasing energy consumption. Second, asphalt modification requires multiple processes such as swelling, shearing, and development, with a relatively complex technological process. In addition, asphalt modification needs to overcome problems such as the compatibility between asphalt and polymers. Therefore, more and more researchers have carried out research on alternative asphalt binders, using a new type of binder to improve the road performance of mixtures.

[0004] Polyurethane materials are a general term for macromolecular compounds containing repeating urethane groups in the main chain, and their raw materials mainly include isocyanates and polyols (amines). Due to the variety of isocyanates and polyols, polyurethane materials have strong controllability. Some researchers have proposed using polyurethane (PU) as a binder to replace asphalt. Polyurethane can be divided into "soft segments" and "hard segments" from the molecular structure. The soft segments provide the ability to deform at low temperatures, and the hard segments provide strength and high-temperature stability, making polyurethane have excellent mechanical properties. It has been found that some road performance of polyurethane mixtures is 5 - 10 times higher than that of ordinary asphalt mixtures, and it is considered a "new generation" pavement binder material.

[0005] The polyurethane binder for road surfaces includes two-component polyurethane and one-component polyurethane. Due to reasons such as the need for precise metering and uniform mixing before using two-component polyurethane, one-component polyurethane is mostly used in polyurethane road surfaces at present. One-component polyurethane is a reactive binder, which needs to contact with moisture in the air to complete the curing of polyurethane through reaction. However, in actual applications, after the one-component polyurethane is mixed with aggregates and then spread on the road surface and rolled by a roller, a dense mixture (especially a dense-graded mixture) is formed. The one-component polyurethane on the road surface can fully contact with the moisture in the air to complete curing, but it is difficult for the one-component polyurethane binder inside and in the lower layer to fully contact with the moisture in the air, resulting in difficulties in the curing of the one-component polyurethane binder and affecting the curing and forming of the polyurethane mixture and its road performance. Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] In view of the technical problems existing in the prior art, the present invention first provides a polyurethane mixture that can promote curing, and the polyurethane mixture of the present invention contains a composite curing material. By using the composite curing material, the polyurethane mixture can be fully cured and formed, and the polyurethane mixture can obtain better road performance.

[0008] Furthermore, the present invention also provides a preparation method of a polyurethane mixture, which is simple and easy to operate, the raw materials are easy to obtain, and it is suitable for mass production.

[0009] Furthermore, the present invention also provides a polyurethane mixture specimen and a preparation method thereof. The polyurethane mixture specimen of the present invention has excellent curing effect and excellent road performance.

[0010] Solutions for Solving the Problems

[0011] The present invention provides a polyurethane mixture, which comprises the following components:

[0012] Graded aggregates,

[0013] Polyurethane, and

[0014] A composite curing material, and a curing agent exists inside the composite curing material; wherein,

[0015] Based on the total mass of the polyurethane mixture, the content of the composite curing material is more than 0.1%, preferably 0.1%-5%.

[0016] According to the polyurethane mixture of the present invention, wherein, the composite curing material includes a porous material and a curing agent; preferably, the mass ratio of the curing agent to the porous material is 0.05-0.3:1.

[0017] The polyurethane mixture according to the present invention, wherein the porous material comprises one or a combination of two or more of molecular sieve, ceramics with micropores or mesopores, fine aggregate with micropores or mesopores, zeolite, and ordered mesoporous material; and / or

[0018] The curing agent comprises one or a combination of two or more of water, polyol, and polyamine.

[0019] The polyurethane mixture according to the present invention, wherein, based on the total mass of the polyurethane mixture being 100%, the content of the graded aggregate is more than 90%, and the content of the polyurethane is 3-9.9%.

[0020] The polyurethane mixture according to the present invention, wherein the grading range of the graded aggregate is as follows:

[0021] The content of the aggregate with a particle size less than 2.36 mm is 30-45%, the content of the aggregate with a particle size of 2.36-4.75 mm is 10-22%, the content of the aggregate with a particle size of 4.75-9.5 mm is 25-35%, and the content of the aggregate with a particle size greater than 9.5 mm is 15-32%.

[0022] The present invention also provides a method for preparing a polyurethane mixture, which includes the step of mixing the components of the polyurethane mixture according to the present invention; preferably, the preparation method includes the following steps:

[0023] The step of preparing a composite curing material;

[0024] The step of mixing the composite curing material with other components of the polyurethane mixture.

[0025] According to the method for preparing a polyurethane mixture of the present invention, wherein the preparation method of the composite curing material includes the following steps: heating the porous material and then mixing it with the curing agent, and drying it at room temperature, so that the curing agent on the surface of the porous material volatilizes and there is curing agent inside, to obtain a composite curing material.

[0026] The present invention also provides a polyurethane mixture specimen, which includes the polyurethane mixture according to the present invention.

[0027] The present invention further provides a method for preparing a polyurethane mixture specimen according to the present invention, which includes the following steps:

[0028] Mixing the polyurethane mixture and then rotocompacting it to form a formed body;

[0029] Making the surface of the formed body contact with air and curing it;

[0030] During the curing process, the formed body is heated once every 0.5 - 5 hours.

[0031] After curing is completed, a polyurethane mixture specimen is obtained.

[0032] According to the method for preparing a polyurethane mixture specimen of the present invention, the formed body is heated by microwave heating; preferably, the power of the microwave heating is 100 - 1000 w.

[0033] Effects of the Invention

[0034] The polyurethane mixture of the present invention contains a composite curing material. By using the composite curing material, the curing degree of the polyurethane mixture can be improved, and the polyurethane mixture can obtain better road - using performance.

[0035] The method for preparing the polyurethane mixture of the present invention is simple and easy to implement, the raw materials are easy to obtain, and it is suitable for mass production.

[0036] The curing effect of the polyurethane mixture specimen of the present invention is excellent, and it has excellent road - using performance. Brief Description of the Drawings

[0037] Figure 1 Shows a flowchart for preparing a polyurethane mixture specimen of the present invention. Detailed Embodiments

[0038] The following will detail various exemplary embodiments, features, and aspects of the present invention. The special word "exemplary" here means "serving as an example, embodiment, or illustrative". Any embodiment described as "exemplary" here does not necessarily have to be interpreted as superior to or better than other embodiments.

[0039] In addition, for a better illustration of the present invention, numerous specific details are given in the following detailed embodiments. Those skilled in the art should understand that the present invention can still be implemented without some specific details. In other instances, methods, means, equipment, and steps well - known to those skilled in the art are not described in detail to highlight the gist of the present invention.

[0040] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0041] In this specification, the meaning expressed by "can" includes both the meaning of performing a certain process and not performing a certain process.

[0042] In this specification, the "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", etc. mentioned refer to the specific elements (e.g., features, structures, properties, and / or characteristics) related to the embodiment, which are included in at least one of the embodiments described herein, and may or may not exist in other embodiments. Additionally, it should be understood that the elements can be combined in various embodiments in any suitable manner.

[0043] In this specification, the numerical range expressed as "numerical value A to numerical value B" refers to the range including the endpoint numerical values A and B.

[0044] In this specification, when "normal temperature" or "room temperature" is used, the temperature can be 10 - 25 °C.

[0045] <First aspect>

[0046] The first aspect of the present invention provides a polyurethane mixture, which comprises the following components:

[0047] Graded aggregate,

[0048] Polyurethane, and

[0049] Composite curing material, in which a curing agent exists inside; wherein,

[0050] Based on the total mass of the polyurethane mixture, the content of the composite curing material is 0.1% or more, preferably 0.1% - 5%.

[0051] The polyurethane mixture of the present invention can improve the curing degree of the polyurethane mixture by using the composite curing material, so that the polyurethane mixture obtains better road performance.

[0052] In the present invention, the composite curing material includes a porous material and a curing agent. In the present invention, by using the porous material to absorb the curing agent, a curing agent exists inside the composite curing material. Due to the capillary action of the porous material, when the surface of the composite curing material volatilizes, the curing agent in the capillary pores of the porous material is still retained. After mixing the composite curing material with the graded aggregate, the graded aggregate contains fine aggregate with a particle size less than 2.36 mm, and the curing agent will be uniformly dispersed into the graded aggregate along with the fine aggregate. Subsequently, it can react with the isocyanate groups in the polyurethane mixture, enabling the polyurethane mixture to be fully cured, and thus obtaining a polyurethane mixture with excellent road performance.

[0053] Further, in the present invention, the composite curing material comprises a porous material and a curing agent; preferably, the mass ratio of the curing agent to the porous material is 0.05 - 0.3:1, for example: 0.08:1, 0.1:1, 0.12:1, 0.15:1, 0.18:1, 0.2:1, 0.22:1, 0.25:1, 0.28:1, etc. Generally speaking, when the mass ratio of the curing agent to the porous material is 0.05 - 0.3:1, the porous material absorbs a relatively large amount of the curing agent, enabling the function of the curing agent to be maximally exerted.

[0054] The porous material is an inorganic non-metallic material with voids. The inventor of the present invention found that after the curing agent is adsorbed into the voids through capillary action, it is difficult to escape under normal conditions, and the curing agent can only volatilize under special conditions such as heating (e.g., microwave heating). The curing agent of the present invention has a small molecular weight and can enter the porous material, and the curing agent can still volatilize under special conditions such as heating (e.g., microwave heating).

[0055] In some specific embodiments, the curing agent of the present invention is a small molecule curing agent, the molecular weight of the small molecule curing agent is below 1000 Da, and the small molecule curing agent can react with the isocyanate in the polyurethane. Specifically, the curing agent includes one or a combination of two or more of water, polyols, and polyamines.

[0056] Specifically, when the curing agent is a polyol, the reaction of isocyanate and polyol is as follows:

[0057]

[0058] When the curing agent is a polyamine, the reaction of isocyanate and polyamine is as follows:

[0059]

[0060] When the curing agent is water, the reaction of isocyanate and water is as follows:

[0061]

[0062] Further, the polyol may be one or a combination of two or more of 1,4 - butanediol, isopentanediol, ethylene glycol, etc., and the polyamine may be one or a combination of two or more of ethylenediamine, m - xylylenediamine, triethylamine, diethylenetriamine, etc.

[0063] In some specific embodiments, for the porous material, the present invention is not particularly limited, and any feasible porous material in the art may be used. Specifically, the porous material includes one or a combination of two or more of molecular sieves, ceramics containing micropores or mesopores, fine aggregates containing micropores or mesopores, zeolites, and ordered mesoporous materials.

[0064] Furthermore, the polyurethane of the present invention preferably refers to one-component polyurethane. One-component polyurethane specifically refers to polyurethane resin with terminal NCO groups. During use, the one-component polyurethane can be directly coated at the desired position, allowing the resin to be exposed to air and react with trace moisture in the air to cure.

[0065] In the present invention, based on the total mass of the polyurethane mixture, the content of the composite curing material is 0.1% or more, preferably 0.1% - 5%, such as: 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, etc. When the content of the composite curing material is 0.1% or more, a certain curing effect can be achieved. Especially when the content of the composite curing material is 0.1% - 5%, the curing effect is the most excellent. This is because when the content of the composite curing material is higher than 5%, its curing ability is too strong, which will affect other properties of the polyurethane mixture to a certain extent.

[0066] In some specific embodiments, based on the total mass of the polyurethane mixture being 100%, the content of the graded aggregate is 90% or more, preferably 90 - 96.9%; such as: 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, etc.; the content of the polyurethane is 3 - 9.9%, such as: 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, etc. When the content of the graded aggregate is 90% or more and the content of the polyurethane is 3 - 9.9%, the properties of the prepared polyurethane mixture are excellent.

[0067] Further, in the present invention, graded aggregate is used as the skeleton structure of the polyurethane mixture.

[0068] Specifically, in the present invention, the grading range of the graded aggregate is: the content of aggregate with a particle size less than 2.36 mm is 30 - 45%, such as: 32%, 34%, 36%, 38%, 40%, 42%, 44%, etc.; the content of aggregate with a particle size of 2.36 - 4.75 mm is 10 - 22%, such as: 12%, 14%, 16%, 18%, 20%, etc.; the content of aggregate with a particle size of 4.75 - 9.5 mm is 25 - 35%, such as: 27%, 29%, 31%, 33%, etc.; the content of aggregate with a particle size of more than 9.5 mm is 15 - 32%, such as: 17%, 19%, 21%, 23%, 25%, 27%, 29%, 31%, etc. When graded aggregate within the above grading range is selected, the curing effect of the prepared polyurethane mixture is more excellent.

[0069] Furthermore, the present invention also provides a method for preparing a polyurethane mixture, which includes the step of mixing the components of the polyurethane mixture described in the present invention.

[0070] Specifically, the preparation method includes the following steps:

[0071] The step of preparing a composite curing material;

[0072] The step of mixing the composite curing material with other components of the polyurethane mixture.

[0073] In some specific embodiments, the preparation method of the composite curing material includes the following steps: heating and drying a porous material, then mixing it with a curing agent and performing surface drying, so that the curing agent on the surface of the porous material volatilizes and there is a curing agent inside, obtaining a composite curing material.

[0074] Specifically, the porous material can be placed in a microwave for heating and drying to remove the moisture in the capillary pores. Then the curing agent is mixed with the porous material and surface drying is performed, so that the curing agent on the surface of the porous material volatilizes and there is a curing agent inside, obtaining a composite curing material. Specifically, it can be placed in a normal temperature environment to volatilize the curing agent on the surface of the porous material (surface drying). In this way, a porous material containing a curing agent inside can be obtained, which is the composite curing material.

[0075] Further, when the curing agent used is a polyol or water, the mass ratio of the porous material to the curing agent can be 1:0.5 - 100, preferably 1:1 - 10, for example: 1:2, 1:5, 1:8, 1:15, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, etc. When the mass ratio of the porous material to the curing agent is 1:0.5 - 100, the porous material can be impregnated in the curing agent as much as possible and absorb as much curing agent as possible, so that the subsequent action of the curing agent can be exerted most effectively.

[0076] When the curing agent used is polyamine, it can be first formulated into a curing agent solution. In the solution, the mass content of the curing agent can be 10 - 90%, for example: 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, etc. Thus, the porous material can be impregnated in the curing agent solution. For the mass ratio of the porous material to the curing agent solution, it can still be 1:0.5 - 100, preferably 1:1 - 10, for example: 1:2, 1:5, 1:8, 1:15, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, etc. When the mass ratio of the porous material to the curing agent solution is 1:0.5 - 100, the porous material can also be impregnated in the curing agent solution as much as possible, absorb as much curing agent as possible, so that the subsequent action of the curing agent can be exerted most effectively.

[0077] Furthermore, for the surface drying time, the present invention does not make a special limitation and can be set as needed, for example: 10 min - 60 min, etc., as long as the surface is dry and the curing agent is stored inside.

[0078] When using this composite curing material, the curing agent inside the composite curing material reacts with the isocyanate groups in the polyurethane mixture to fully cure the polyurethane curing agent, and then a polyurethane mixture with excellent road - using performance is obtained.

[0079] In some specific embodiments, after mixing the graded aggregate with the composite curing material, it is then mixed with polyurethane to obtain a polyurethane mixture. For the mixing method, the present invention does not make a special limitation and can be mixed by common methods in the art.

[0080] <Second aspect>

[0081] The second aspect of the present invention provides a polyurethane mixture specimen, which includes the polyurethane mixture according to the first aspect of the present invention.

[0082] The polyurethane mixture specimen of the present invention has excellent curing effect and excellent road - using performance.

[0083] In the present invention, after the composite curing material is fully mixed with the graded aggregate, during the forming process of the polyurethane mixture, it can be formed according to normal gradation and methods.

[0084] Specifically, the preparation method of the polyurethane mixture specimen of the present invention includes the following steps:

[0085] Mix the polyurethane mixture and then rotate and compact it to form a formed body;

[0086] Make the surface of the formed body contact with air and cure it;

[0087] During the curing process, the formed body is heated once every 0.5 - 5 hours, such as 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, etc.

[0088] After curing is completed, a polyurethane mixture specimen is obtained.

[0089] By heating, the curing agent inside the porous material evaporates, providing the necessary curing conditions for the curing of polyurethane. Thus, effectively solving the problem that after the mixture is compacted, the polyurethane cannot fully contact with the moisture in the air, which affects the curing and forming of the polyurethane mixture.

[0090] In some specific embodiments, the formed body can be heated by microwave heating. By controlling the action of microwave on the mixture, the curing agent can be continuously provided for the polyurethane mixture. The curing agent reacts with the isocyanate groups in the polyurethane mixture, enabling the one-component polyurethane mixture to be fully cured, and thus obtaining excellent road-use performance of the mixture.

[0091] Specifically, in the present invention, the power of microwave heating is not particularly limited and can be selected according to needs. Specifically, in the present invention, the power of the microwave heating is 100 - 1000 w, for example: 200 w, 400 w, 600 w, 800 w, etc.

[0092] Furthermore, in order to more effectively exert the role of the composite curing material, the surrounding and bottom surface of the formed body can be sealed with tape or plasticine, and only the surface of the formed body is in contact with the air. This can better simulate the actual situation and further highlight the role of the composite curing material in promoting the curing and forming of the one-component polyurethane.

[0093] Examples

[0094] The following will describe the embodiments of the present invention in detail in combination with examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. For those not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. For the reagents or instruments not specified in the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0095] In the examples, the AC - 13 gradation is shown in Table 1 below;

[0096] The manufacturer of the one-component polyurethane is Wanhua Chemical Group Co., Ltd.

[0097] Table 1 Aggregate gradation range of AC - 13 dense-graded polyurethane concrete mixture

[0098]

[0099] Example 1

[0100] First, add 20 g of heat-dried molecular sieve porous material (type 13X) to 100 ml of distilled water. Under ultrasonic vibration conditions, mix the molecular sieve porous material and water for 30 min. Then, filter the molecular sieve porous material with filter paper and evaporate it in an environment of 25 °C until the surface of the molecular sieve porous material is dry to obtain a composite cured material; among them, the mass ratio of the curing agent to the porous material is 0.2:1.

[0101] Weigh 1195 g of each graded aggregate (dried) according to the median value of the above AC-13 gradation. Subsequently, weigh 5 g of the composite cured material and uniformly mix it in 1195 g of the graded aggregate to obtain a mixed product. Then, weigh 62.4 g of one-component polyurethane and mix it evenly with the mixed aggregate to obtain a polyurethane mixture.

[0102] Use a rotary compactor to form the polyurethane mixture into a formed body. Seal the bottom and side surfaces of the formed body with tape (only leaving the top surface in contact with the air), and place the formed body in a constant temperature and humidity chamber (temperature 25 °C, humidity RH50%) for curing for 24 h to obtain a polyurethane mixture specimen. During the curing process, take out the formed body every 2 h and place it in a microwave test chamber for microwave heating for 30 s, where the microwave power is 300 w, and then put it back into the constant temperature and humidity chamber to continue curing.

[0103] Example 2

[0104] First, add 20 g of heat-dried molecular sieve porous material (type 13X) to 100 ml of distilled water. Under ultrasonic vibration conditions, mix the molecular sieve porous material and water for 30 min. Then, filter the molecular sieve porous material with filter paper and evaporate it in an environment of 25 °C until the surface of the molecular sieve porous material is dry to obtain a composite cured material; among them, the mass ratio of the curing agent to the porous material is 0.2:1.

[0105] Weigh 1190 g of each graded aggregate (dried) according to the median value of the above AC-13 gradation. Subsequently, weigh 10 g of the composite cured material and uniformly mix it in 1190 g of the graded aggregate to obtain a mixed product. Then, weigh 62.4 g of one-component polyurethane and mix it evenly with the mixed product to obtain a polyurethane mixture.

[0106] Use a rotary compactor to form the polyurethane mixture into a formed body. Seal the bottom and side surfaces of the formed body with tape (only leaving the top surface in contact with the air), and place the formed body in a constant temperature and humidity chamber (temperature 25 °C, humidity RH50%) for curing for 24 h to obtain a polyurethane mixture specimen. During the curing process, take out the formed body every 2 h and place it in a microwave test chamber for microwave heating for 30 s, where the microwave heater power is 300 w, and then put it back into the constant temperature and humidity chamber to continue curing.

[0107] Example 3

[0108] First, add 20 g of heat-dried molecular sieve porous material (type 13X) to 100 ml of distilled water. Under ultrasonic vibration conditions, mix the molecular sieve porous material and water for 30 min. Then, filter the molecular sieve porous material with filter paper and evaporate it in an environment of 25 °C until the surface of the molecular sieve porous material is dry to obtain a composite solidified material; wherein, the mass ratio of the curing agent to the porous material is 0.2:1.

[0109] Weigh 1185 g of each graded aggregate (dried) according to the median value of the above AC-13 gradation. Subsequently, weigh 15 g of the composite solidified material and uniformly mix it in 1185 g of the graded aggregate to obtain a mixed product. Then, weigh 62.4 g of one-component polyurethane and mix it evenly with the mixed product to obtain a polyurethane mixture.

[0110] Use a rotary compactor to form the polyurethane mixture into a formed body. Seal the bottom and side surfaces of the formed body with tape (only leaving the top surface in contact with the air), and place the formed body in a constant temperature and humidity chamber (temperature 25 °C, humidity RH50%) for 24 h of curing to obtain a polyurethane mixture specimen. During the curing process, take out the formed body every 2 h and place it in a microwave test chamber for microwave heating for 30 s, where the power of the microwave heater is 300 w, and then put it back into the constant temperature and humidity chamber to continue curing.

[0111] Example 4

[0112] First, add 20 g of heat-dried molecular sieve porous material (type 13X) to 100 ml of ethylene glycol. Under ultrasonic vibration conditions, mix the molecular sieve porous material and ethylene glycol for 30 min. Then, filter the molecular sieve porous material with filter paper and evaporate it in an environment of 25 °C until the surface of the molecular sieve porous material is dry to obtain a composite solidified material; wherein, the mass ratio of the curing agent to the porous material is 0.2:1.

[0113] Weigh 1200 g of each graded aggregate (dried) according to the median value of the above AC-13 gradation. Subsequently, weigh 15 g of the composite solidified material and uniformly mix it in 1185 g of the graded aggregate to obtain a mixed product. Then, weigh 62.4 g of one-component polyurethane and mix it evenly with the mixed product to obtain a polyurethane mixture.

[0114] Use a rotary compactor to form the polyurethane mixture into a formed body. Seal the bottom and side surfaces of the formed body with tape (only leaving the top surface in contact with the air), and place the formed body in a constant temperature and humidity chamber (temperature 25 °C, humidity RH50%) for 24 h of curing to obtain a polyurethane mixture specimen. During the curing process, take out the formed body every 2 h and place it in a microwave test chamber for microwave heating for 30 s, where the power of the microwave heater is 300 w, and then put it back into the constant temperature and humidity chamber to continue curing.

[0115] Example 5

[0116] First, add 20 g of heat-dried molecular sieve porous material (type 13X) to 100 ml of ethylenediamine solution (mass content 50%, solvent is water). Under ultrasonic vibration conditions, mix the molecular sieve porous material and the ethylenediamine solution for 30 min. Then, filter the molecular sieve porous material with filter paper and evaporate it at 25 °C until the surface of the molecular sieve porous material is dry to obtain a composite cured material; among them, the mass ratio of the curing agent to the porous material is 0.2:1.

[0117] Weigh 1200 g of each gradation of mineral aggregate (dried) according to the median value of the above AC-13 gradation. Subsequently, weigh 15 g of the composite cured material and uniformly mix it in 1185 g of the mineral aggregate to make a mixed mineral aggregate. Then, weigh 62.4 g of one-component polyurethane and mix it evenly with the mixed mineral aggregate to obtain a polyurethane mixture.

[0118] Use a rotary compactor to form the polyurethane mixture into a formed body. Seal the bottom and side surfaces of the formed body with tape (only leaving the top surface in contact with the air), and place the formed body in a constant temperature and humidity chamber (temperature 25 °C, humidity RH50%) for curing for 24 h to obtain a polyurethane mixture specimen. During the curing process, take out the formed body every 2 h and place it in a microwave test chamber for microwave heating for 30 s, where the power of the microwave heater is 300 w, and then put it back into the constant temperature and humidity chamber to continue curing.

[0119] Comparative Example 1

[0120] Weigh 1200 g of each gradation type of mineral aggregate (dried) according to the AC-13 gradation, and weigh 62.4 g of one-component polyurethane and mix it evenly with the gradation type of mineral aggregate to obtain a polyurethane mixture.

[0121] Use a rotary compactor to form the polyurethane mixture into a formed body. Seal the bottom and side surfaces of the formed body with tape (only leaving the top surface in contact with the air), and place the formed body in a constant temperature and humidity chamber (temperature 25 °C, humidity RH50%) for curing for 24 h to obtain a polyurethane mixture specimen. During the curing process, take out the formed body every 2 h and place it in a microwave test chamber for microwave heating for 30 s, where the power of the microwave heater is 300 w, and then put it back into the constant temperature and humidity chamber to continue curing. After curing is completed, a polyurethane mixture specimen is obtained.

[0122] Performance test

[0123] Conduct Marshall stability tests and splitting strength tests on the polyurethane mixture specimens according to the test methods of T 0709 and T 0716 in the "Test Procedures for Bitumen and Bituminous Mixtures in Highway Engineering" (JTGE20-2011), and compare the test results of the examples and the comparative examples. The results are shown in Table 2.

[0124] Table 2 Test Results of Marshall Stability and Splitting Strength of Polyurethane Mixture Specimens

[0125]

[0126] As can be seen from Table 2, with the increase in the addition amount of the composite curing material, the Marshall stability and splitting strength of the polyurethane mixture show an increasing trend. This indicates that by adding the composite curing material, the reaction of the one-component polyurethane in the polyurethane mixture can be promoted. The increase in the composite curing material results in more "release points" of small molecule curing agents in the polyurethane mixture, enabling the one-component polyurethane mixture to react and cure more fully, endowing the polyurethane mixture with higher stability values, splitting strength, and other road performance properties.

[0127] In addition, by comparing Example 3, Example 4, and Example 5, it is found that ethylene glycol, water, and ethylenediamine can all promote the curing of one-component polyurethane. In terms of the curing promotion effect, the composite curing agent ethylenediamine > water > ethylene glycol.

[0128] It should be noted that although the technical solutions of the present invention are introduced with specific examples, those skilled in the art can understand that the present invention should not be limited thereto.

[0129] The above has described the embodiments of the present invention. The above description is exemplary and not exhaustive, and is also not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technologies in the market, or to enable other ordinary skilled persons in the technical field to understand the disclosed embodiments.

Claims

1. A polyurethane mixture, characterized in that, it comprises the following components: graded aggregate, polyurethane, and a composite curing material, wherein a curing agent is present inside the composite curing material; wherein, based on the total mass of the polyurethane mixture, the content of the composite curing material is 0.1% - 5%; the composite curing material comprises a porous material and a curing agent; wherein, the porous material is an inorganic non-metallic material with voids, the curing agent is a small molecule curing agent, and the molecular weight of the small molecule curing agent is below 1000 Da; wherein, the preparation method of the composite curing material comprises the following steps: heating and drying the porous material, then mixing it with the curing agent and performing surface drying, so that the curing agent on the surface of the porous material volatilizes and there is a curing agent inside, obtaining the composite curing material; the mass ratio of the curing agent to the porous material is 0.05 - 0.3:

1.

2. The polyurethane mixture according to claim 1, characterized in that, the porous material comprises one or a combination of two or more of molecular sieve, ceramics containing micropores or mesopores, fine aggregate containing micropores or mesopores, zeolite, ordered mesoporous material; and / or the curing agent comprises one or a combination of two or more of water, polyol, polyamine.

3. The polyurethane mixture according to claim 1 or 2, characterized in that, based on 100% of the total mass of the polyurethane mixture, the content of the graded aggregate is more than 90%, and the content of the polyurethane is 3 - 9.9%.

4. The polyurethane mixture according to claim 1 or 2, characterized in that, the grading range of the graded aggregate is: the content of the aggregate with a particle size less than 2.36 mm is 30 - 45%, the content of the aggregate with a particle size of 2.36 - 4.75 mm is 10 - 22%, the content of the aggregate with a particle size of 4.75 - 9.5 mm is 25 - 35%, and the content of the aggregate with a particle size of more than 9.5 mm is 15 - 32%.

5. A preparation method of the polyurethane mixture according to any one of claims 1 - 4, characterized in that, the preparation method comprises the following steps: the step of preparing the composite curing material; the step of mixing the composite curing material with other components of the polyurethane mixture; the preparation method of the composite curing material comprises the following steps: heating and drying the porous material, then mixing it with the curing agent and performing surface drying, so that the curing agent on the surface of the porous material volatilizes and there is a curing agent inside, obtaining the composite curing material.

6. A polyurethane mixture specimen, characterized in that, it comprises the polyurethane mixture according to any one of claims 1 - 4.

7. A preparation method of the polyurethane mixture specimen according to claim 6, characterized in that, it comprises the following steps: mixing the polyurethane mixture and rotating and compacting it to form a formed body; making the surface of the formed body contact with air and performing curing; during the curing process, heating the formed body once every 0.5 - 5 hours; after the curing is completed, obtaining the polyurethane mixture specimen.

8. The preparation method of the polyurethane mixture specimen according to claim 7, characterized in that, the formed body is heated by means of microwave heating.

9. The preparation method of the polyurethane mixture specimen according to claim 8, characterized in that, the power of the microwave heating is 100-1000w.

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