Wide-temperature-range multi-stage phase change temperature regulating asphalt mixture and preparation method thereof

Abstract

The application discloses a preparation method of wide-temperature-range multi-stage phase change temperature regulating asphalt mixture, which comprises the following steps: preparing a plurality of different composite organic eutectic phase change materials respectively; compounding the plurality of different composite organic eutectic phase change materials according to different proportions to obtain a wide-temperature-range multi-stage phase change material; and adding the wide-temperature-range multi-stage phase change material into asphalt mixture at a mass ratio of 3% to 5% to form the wide-temperature-range multi-stage phase change temperature regulating asphalt mixture. The wide-temperature-range multi-stage phase change temperature regulating asphalt mixture can continuously play the phase change heat storage function under a high-temperature environment in summer, delay the temperature change rate of the road surface, reduce the maximum temperature of the road surface, delay the appearance time of the daily maximum, and reduce the surface layer temperature of the road surface, so that the urban heat island effect can be relieved and the durability of the road surface can be prolonged.

Description

Technical Field

[0001] This invention belongs to the field of road engineering technology, specifically relating to a wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture and its preparation method. Background Technology

[0002] Asphalt pavement is widely used in urban roads and highway construction due to its high durability, low noise, excellent wear resistance, and comfort. However, black asphalt pavement has a heat absorption coefficient as high as 0.82 to 0.92, absorbing up to 90% of solar radiation. Against the backdrop of global warming and frequent high-temperature summers, asphalt pavement can convert solar energy into heat, leading to heat accumulation and temperature increases within the pavement structure. In most parts of the country, the average maximum temperature in July exceeds 35℃, causing the surface temperature of asphalt pavement to reach 60℃, while the temperature at the bottom of the upper layer reaches as high as 56℃.

[0003] On the one hand, high temperatures soften asphalt pavements and cause them to lose rigidity, leading to deformation, dents, and wear under the stress of vehicle loads and traffic flow. When the asphalt pavement temperature is below 55°C, ruts can be controlled within a few millimeters, but when the pavement temperature exceeds 55°C, ruts develop at a centimeter-level speed, significantly reducing pavement durability. On the other hand, the accelerated urbanization process has led to a surge in human activity, resulting in the urban heat island effect. The direct impact of the urban heat island effect on urban livability is mainly reflected in the decline of environmental quality, the exacerbation of heat stress, and the acceleration of heat-related public health problems; extreme urban heat island events can significantly exacerbate global warming and high mortality rates. This phenomenon can be attributed to several factors, including the use of thermally inert materials and dark-colored surface building materials, complex urban landscape geometry, reduced vegetation cover, and significantly increased anthropogenic energy consumption. Among these factors, black paved asphalt pavements account for more than 30% of the total urban area, making the elevated pavement temperature one of the main factors contributing to the heat island effect. Therefore, there is an urgent need to adopt effective strategies to reduce the temperature of asphalt pavements in the high-temperature environment of summer, so as to improve the durability of the pavement and alleviate the urban heat island effect. Summary of the Invention

[0004] To address the aforementioned problems in the existing technology, this invention provides a wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture and its preparation method. The technical problem to be solved by this invention is achieved through the following technical solution:

[0005] One aspect of the present invention provides a method for preparing a wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture, comprising:

[0006] S1: Prepare various composite organic eutectic phase change materials respectively;

[0007] S2: The various composite organic eutectic phase change materials are compounded in different proportions to obtain a wide-temperature-range multi-stage phase change material;

[0008] S3: The wide-temperature-range multi-stage phase change material is incorporated into the asphalt mixture at a mass ratio of 3% to 5% to form the wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture.

[0009] In one embodiment of the present invention, the various composite organic eutectic phase change materials include CPCM1, CPCM2, CPCM3, CPCM4, CPCM5, CPCM6, and CPCM7 composite organic eutectic phase change materials, wherein...

[0010] The raw materials of the CPCM1 composite organic eutectic phase change material are 133-173 parts by mass of palmitic acid, 223-263 parts by mass of myristic acid, 584-624 parts by mass of methyl stearate, and 90-110 parts by mass of expanded graphite.

[0011] The raw materials for the CPCM2 composite organic eutectic phase change material are 128-168 parts by mass of palmitic acid, 832-872 parts by mass of methyl stearate, and 90-110 parts by mass of expanded graphite.

[0012] The raw materials for the CPCM3 composite organic eutectic phase change material are 180-220 parts by weight of stearic acid, 270-330 parts by weight of palmitic acid, 440-540 parts by weight of myristic acid, and 90-110 parts by weight of expanded graphite.

[0013] The raw materials of the CPCM4 composite organic eutectic phase change material are 105-145 parts by mass of butyramide, 855-895 parts by mass of myristic acid, and 90-110 parts by mass of expanded graphite.

[0014] The raw materials for the CPCM5 composite organic eutectic phase change material are 360-440 parts by weight of stearic acid, 540-660 parts by weight of palmitic acid, and 90-110 parts by weight of expanded graphite.

[0015] The raw materials for the CPCM6 composite organic eutectic phase change material are 121-161 parts by mass of butyramide, 839-879 parts by mass of palmitic acid, and 90-110 parts by mass of expanded graphite.

[0016] The raw materials for the CPCM7 composite organic eutectic phase change material are 134-174 parts by mass of butyramide, 826-866 parts by mass of stearic acid, and 90-110 parts by mass of expanded graphite.

[0017] In one embodiment of the present invention, the preparation process of the CPCM1 composite organic eutectic phase change material includes:

[0018] 133-173 parts by weight of palmitic acid, 223-263 parts by weight of myristic acid, and 584-624 parts by weight of methyl stearate are heated until completely melted and stirred thoroughly to form a blended mixture.

[0019] Add 90-110 parts by mass of expanded graphite to the blended mixture, stir and adsorb under vacuum at 70-90°C for 4-6 hours, and then place it in a vacuum drying oven to continue adsorption for 40-55 hours.

[0020] The adsorption-completed mixture was removed, rinsed repeatedly with anhydrous ethanol, and then dried in an oven to obtain the CPCM1 composite organic eutectic phase change material.

[0021] In one embodiment of the present invention, the preparation process of the CPCM2 composite organic eutectic phase change material includes:

[0022] 128–168 parts by weight of palmitic acid and 832–872 parts by weight of methyl stearate were heated until completely melted and stirred thoroughly to form a blended mixture. 90–110 parts by weight of expanded graphite were added to the blended mixture, and the mixture was stirred and adsorbed under vacuum at 70–90°C for 4–6 hours. The mixture was then placed in a vacuum drying oven for further adsorption for 40–55 hours. The adsorbed mixture was removed, rinsed repeatedly with anhydrous ethanol, and dried in an oven to obtain the CPCM1 composite organic eutectic phase change material.

[0023] In one embodiment of the present invention, S2 includes:

[0024] A wide-temperature-range multi-stage phase change material is obtained by mixing CPCM1 composite organic eutectic phase change material (2-8% by mass), CPCM2 composite organic eutectic phase change material (17-23% by mass), CPCM3 composite organic eutectic phase change material (27-33% by mass), CPCM4 composite organic eutectic phase change material (17-23% by mass), CPCM5 composite organic eutectic phase change material (7-13% by mass), CPCM6 composite organic eutectic phase change material (7-13% by mass), and CPCM7 composite organic eutectic phase change material (2-8% by mass).

[0025] In one embodiment of the present invention, the asphalt mixture comprises mineral aggregates, mineral powder, and asphalt, wherein S3 comprises:

[0026] Dry mineral aggregates of various specifications for later use, and melt asphalt and heat it to the specified asphalt mixture mixing temperature for later use.

[0027] Preheat the asphalt mixture mixing plant to a predetermined temperature above the required mixing temperature, and then place the various specifications of mineral aggregates into the asphalt mixture mixing plant for mixing.

[0028] Add the required asphalt, heated to the mixing temperature, to the asphalt mixture mixing plant and continue mixing. Then pause mixing and add mineral powder and wide-temperature-range multi-stage phase change material, both heated to the mixing temperature, to the asphalt mixture mixing plant. Continue mixing until the mixture is homogeneous to obtain the wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture.

[0029] In one embodiment of the present invention, the asphalt is SBS polymer-modified asphalt.

[0030] In one embodiment of the present invention, S3 further includes:

[0031] Before use, the prepared wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture should be kept within the predetermined mixing temperature range.

[0032] Another aspect of the present invention provides a wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture, which is prepared using the preparation method described in any one of the above embodiments.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] 1. The wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture prepared by the preparation method of the present invention can endow the asphalt mixture with heat storage and temperature regulation function by relying on the latent heat characteristics of the phase change material. This can reduce the maximum temperature of the road surface while delaying the occurrence time of the highest temperature of the day and reducing the surface temperature of the road surface, thereby alleviating the urban heat island effect and extending the durability of the road surface.

[0035] 2. The wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture prepared using the method of this invention, due to the introduction of a multi-stage phase change system, possesses the characteristic of stepwise phase change, enabling it to continuously and efficiently exert its latent heat temperature-regulating function within the range of 30–70℃. The wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture of this invention changes at a more stable rate during temperature variations, reducing damage to the pavement structure caused by drastic temperature fluctuations. Especially during seasonal transitions, when temperature differences are significant, the wide-temperature-range multi-stage phase change material provided by this invention can effectively absorb and release heat, reducing pavement expansion and contraction caused by temperature differences, avoiding cracks and surface damage, and improving the overall performance of the pavement.

[0036] 3. The wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture prepared using the method of this invention can effectively reduce the urban heat island effect by reducing the heat radiation and heat absorption of the road surface during high-temperature periods. Especially in summer, by reducing the impact of road surface temperature on the surrounding air temperature, it can alleviate the problem of excessively high temperatures in the city center, thereby improving the quality of the urban ecological environment. In addition, the reusability and long service life of phase change materials also make this technology highly environmentally friendly and economically beneficial.

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0038] Figure 1 This is a flowchart of a method for preparing a wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture according to an embodiment of the present invention;

[0039] Figure 2 These are the heat flow curves of different composite organic eutectic phase change materials provided in the embodiments of the present invention;

[0040] Figure 3 These are the temperature rise curves of different asphalt mixtures and the temperature difference curves between them and ordinary asphalt mixtures provided in the embodiments of the present invention.

[0041] Explanation of reference numerals in the attached figures: Detailed Implementation

[0042] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture and its preparation method based on the present invention.

[0043] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a more in-depth and concrete understanding can be gained of the technical means and effects adopted by the present invention to achieve its intended purpose. However, the accompanying drawings are for reference and illustration only and are not intended to limit the technical solutions of the present invention.

[0044] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes said element.

[0045] Example 1

[0046] This embodiment obtains phase change materials with corresponding temperature requirements through eutectic methods, using these as the core unit for phase change temperature regulation. Expanded graphite is used as the encapsulation carrier structure to prepare various composite organic eutectic phase change materials with different phase change temperatures. By mixing these composite organic eutectic phase change materials in a certain proportion and adding them to asphalt mixtures, a wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture is obtained. This wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture has a temperature regulation and cooling effect across the entire temperature range in the high-temperature environment of asphalt pavement in summer. It can continuously exert the phase change heat storage function in the high-temperature environment of summer, thereby slowing down the rate of change of pavement temperature, reducing the maximum pavement temperature, and delaying the occurrence time of the highest daily temperature, thus alleviating the urban heat island effect and extending pavement durability.

[0047] This embodiment is based on the compounding of various composite organic eutectic phase change materials in different proportions to obtain a wide-temperature-range multi-stage phase change material; subsequently, the wide-temperature-range multi-stage phase change material is incorporated into asphalt mixture as an external additive at a predetermined mass ratio. Please refer to... Figure 1 , Figure 1 This is a flowchart illustrating a method for preparing a wide-temperature-range, multi-stage phase change temperature-regulating asphalt mixture according to an embodiment of the present invention. The specific preparation method includes the following steps:

[0048] S1: Prepare various composite organic eutectic phase change materials respectively.

[0049] In this embodiment, various composite organic eutectic phase change materials include CPCM1, CPCM2, CPCM3, CPCM4, CPCM5, CPCM6, and CPCM7. CPCM1 is composed of 133-173 parts by mass of palmitic acid, 223-263 parts by mass of myristic acid, 584-624 parts by mass of methyl stearate, and 90-110 parts by mass of expanded graphite. CPCM2 is composed of 128-168 parts by mass of palmitic acid, 832-872 parts by mass of methyl stearate, and 90-110 parts by mass of expanded graphite. CPCM3 is composed of 180-220 parts by mass of stearate. The raw materials for CPCM4 composite organic eutectic phase change material are 105-145 parts by weight of butyramide, 855-895 parts by weight of myristic acid, and 90-110 parts by weight of expanded graphite; the raw materials for CPCM5 composite organic eutectic phase change material are 360-440 parts by weight of stearic acid, 540-660 parts by weight of... The raw materials for CPCM6 composite organic eutectic phase change material are 121-161 parts by mass of butyramide, 839-879 parts by mass of palmitic acid, and 90-110 parts by mass of expanded graphite; the raw materials for CPCM7 composite organic eutectic phase change material are 134-174 parts by mass of butyramide, 826-866 parts by mass of stearic acid, and 90-110 parts by mass of expanded graphite.

[0050] In other embodiments, other suitable composite organic eutectic phase change materials may also be included, which will not be described in detail here.

[0051] The above seven composite organic eutectic phase change materials all use organic eutectic phase change materials as the core energy storage unit for phase change and expanded graphite as the encapsulation carrier, and are synthesized through a vacuum impregnation adsorption method. Specifically, the preparation process of CPCM1 composite organic eutectic phase change material includes:

[0052] 133–173 parts by weight of palmitic acid, 223–263 parts by weight of myristic acid, and 584–624 parts by weight of methyl stearate were heated until completely melted and stirred thoroughly to form a blended mixture. 90–110 parts by weight of expanded graphite were added to the blended mixture, and the mixture was stirred and adsorbed under vacuum at 70–90°C for 4–6 hours. The mixture was then placed in a vacuum drying oven for further adsorption for 40–55 hours. The adsorbed mixture was removed, rinsed repeatedly with anhydrous ethanol, and dried in an oven to obtain CPCM1 composite organic eutectic phase change material.

[0053] Similar to the preparation process of the CPCM1 composite organic eutectic phase change material described above, the preparation of CPCM2 to CPCM7 composite organic eutectic phase change materials simply requires replacing different organic phase change materials according to the corresponding proportions. For example, the preparation process of the CPCM2 composite organic eutectic phase change material includes:

[0054] 128–168 parts by mass of palmitic acid and 832–872 parts by mass of methyl stearate were heated until completely melted and stirred thoroughly to form a blended mixture. 90–110 parts by mass of expanded graphite were added to the blended mixture, and the mixture was stirred and adsorbed under vacuum at 70–90°C for 4–6 hours. The mixture was then placed in a vacuum drying oven for further adsorption for 40–55 hours. The adsorbed mixture was removed, rinsed repeatedly with anhydrous ethanol, and dried in an oven to obtain CPCM1 composite organic eutectic phase change material.

[0055] The preparation process of CPCM3 composite organic eutectic phase change material to CPCM7 composite organic eutectic phase change material is the same as the preparation process described above, and will not be repeated here.

[0056] Please see Figure 2 , Figure 2 The figures show the heat flow curves of different composite organic eutectic phase change materials provided in the embodiments of the present invention. As can be seen from the figures, the seven composite organic eutectic phase change materials have obvious latent heat peaks, which range from 30 to 70°C. The peak values ​​of two adjacent composite organic eutectic phase change materials differ by about 4 to 7°C, and the phase change occurs gradually from 30°C to 70°C. These effects mean that the composite organic eutectic phase change materials prepared by the preparation method of the present invention can completely cover the high-temperature environment of asphalt pavement in summer, thereby achieving a wide temperature range (30 to 70°C) gradual phase change and continuously and efficiently exerting its latent heat characteristics.

[0057] S2: By compounding various composite organic eutectic phase change materials in different proportions, a wide-temperature-range multi-stage phase change material is obtained.

[0058] In this embodiment, 2-8% by mass of CPCM1 composite organic eutectic phase change material, 17-23% by mass of CPCM2 composite organic eutectic phase change material, 27-33% by mass of CPCM3 composite organic eutectic phase change material, 17-23% by mass of CPCM4 composite organic eutectic phase change material, 7-13% by mass of CPCM5 composite organic eutectic phase change material, 7-13% by mass of CPCM6 composite organic eutectic phase change material, and 2-8% by mass of CPCM7 composite organic eutectic phase change material are mixed to obtain a wide-temperature-range multi-stage phase change material.

[0059] S3: Wide-temperature-range multi-stage phase change material is added to asphalt mixture at a mass ratio of 3% to 5% to form wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture.

[0060] The asphalt mixture in this embodiment includes mineral aggregates, mineral powder, and asphalt. Step S3 specifically includes:

[0061] Various sizes of mineral aggregates are dried and set aside. Asphalt is melted and heated to the specified asphalt mixture mixing temperature and set aside. The asphalt mixture mixing plant is preheated to a predetermined temperature above the required mixing temperature. Various sizes of mineral aggregates are placed in the asphalt mixture mixing plant for mixing. The required heated asphalt to the mixing temperature is added to the asphalt mixture mixing plant and mixing continues. Then, mixing is paused. Mineral powder and wide-temperature-range multi-stage phase change material that have been heated to the mixing temperature are added to the asphalt mixture mixing plant and mixing continues until the mixture is uniform, thus obtaining a wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture.

[0062] In addition, step S3 also includes maintaining the prepared wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture within a predetermined mixing temperature range before use (e.g., before road paving).

[0063] Preferably, the asphalt used in this embodiment is SBS polymer-modified asphalt.

[0064] Example 2

[0065] Based on Example 1, this example provides another method for preparing a wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture, which includes:

[0066] Step 1: Prepare 7 different composite organic eutectic phase change materials.

[0067] These seven different composite organic eutectic phase change materials include CPCM1, CPCM2, CPCM3, CPCM4, CPCM5, CPCM6, and CPCM7. CPCM1's raw materials are 153 parts by mass of palmitic acid, 243 parts by mass of myristic acid, 604 parts by mass of methyl stearate, and 100 parts by mass of expanded graphite. CPCM2's raw materials are 148 parts by mass of palmitic acid, 852 parts by mass of methyl stearate, and 100 parts by mass of expanded graphite. CPCM3's raw materials are... The raw materials for CPCM4 composite organic eutectic phase change material are: 200 parts by weight of stearic acid, 300 parts by weight of palmitic acid, 490 parts by weight of myristic acid, and 100 parts by weight of expanded graphite; 200 parts by weight of stearic acid, 300 parts by weight of palmitic acid, 490 parts by weight of myristic acid, and 100 parts by weight of expanded graphite; 200 parts by weight of butyramide, 300 parts by weight of palmitic acid, 490 parts by weight of myristic acid, and 100 parts by weight of expanded graphite; 200 parts by weight of butyramide, 300 parts by weight of palmitic acid, 490 parts by weight of myristic acid, and 100 parts by weight of expanded graphite; 200 parts by weight of butyramide, 400 parts by weight of palmitic acid, 490 parts by weight of myristic acid, and 100 parts by weight of expanded graphite; 200 parts by weight of butyramide, 400 parts by weight of palmitic acid, 490 parts by weight of myristic acid, and 100 parts by weight of expanded graphite; 200 parts by weight of butyramide, 490 parts by weight of palmitic ...

[0068] Specifically, the preparation process of CPCM1 composite organic eutectic phase change material includes:

[0069] 153 parts by mass of palmitic acid, 243 parts by mass of myristic acid, and 604 parts by mass of methyl stearate were heated until completely melted and mixed at 300 rad / min for 4 hours. After thorough stirring, a blended mixture was formed. 100 parts by mass of 50-mesh expanded graphite were added to the blended mixture, and the mixture was stirred and adsorbed under vacuum at 80°C for 5 hours. Then, it was placed in a vacuum drying oven for further adsorption for 48 hours. The adsorbed mixture was taken out, stirred and washed five times with anhydrous ethanol, and then dried in an oven at 80°C for 24 hours to obtain CPCM1 composite organic eutectic phase change material.

[0070] Similar to the preparation process of the CPCM1 composite organic eutectic phase change material described above, the preparation of CPCM2 to CPCM7 composite organic eutectic phase change materials simply requires replacing different organic phase change materials according to the corresponding proportions. For example, the preparation process of the CPCM2 composite organic eutectic phase change material includes:

[0071] 153 parts by mass of palmitic acid, 243 parts by mass of myristic acid, and 604 parts by mass of methyl stearate were heated until completely melted and mixed at 300 rad / min for 4 hours. After thorough stirring, a blended mixture was formed. 100 parts by mass of 50-mesh expanded graphite were added to the blended mixture, and the mixture was stirred and adsorbed under vacuum at 80°C for 5 hours. Then, it was placed in a vacuum drying oven for further adsorption for 48 hours. The adsorbed mixture was taken out, stirred and washed five times with anhydrous ethanol, and then dried in an oven at 80°C for 24 hours to obtain CPCM1 composite organic eutectic phase change material.

[0072] The preparation process of CPCM3 composite organic eutectic phase change material to CPCM7 composite organic eutectic phase change material is the same as the preparation process described above, and will not be repeated here.

[0073] Step 2: Seven different composite organic eutectic phase change materials are compounded in different proportions to obtain a wide-temperature-range multi-stage phase change material.

[0074] Specifically, a wide-temperature-range multi-stage phase change material is obtained by compounding 5% by mass of CPCM1 composite organic eutectic phase change material, 20% by mass of CPCM2 composite organic eutectic phase change material, 30% by mass of CPCM3 composite organic eutectic phase change material, 20% by mass of CPCM4 composite organic eutectic phase change material, 10% by mass of CPCM5 composite organic eutectic phase change material, 10% by mass of CPCM6 composite organic eutectic phase change material, and 5% by mass of CPCM7 composite organic eutectic phase change material.

[0075] S3: Wide-temperature-range multi-stage phase change material is added to asphalt mixture at a mass ratio of 3% to 5% to form wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture.

[0076] The following experiments further describe the effect of the wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture prepared in this embodiment. The asphalt mixture includes mineral aggregates, mineral powder, and SBS polymer-modified asphalt. The mix proportions of the asphalt mixture are shown in Table 1. The raw materials required for the wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture include: mineral aggregates, mineral powder, SBS polymer-modified asphalt, and wide-temperature-range multi-stage phase change materials. The gradation of the mineral aggregates adopts the median value of the gradation range required in the "Technical Specification for Construction of Highway Asphalt Pavement" (JTG F40-2004).

[0077] Specifically, mineral aggregates of various specifications (different coarseness) are dried and prepared for use, while asphalt is melted and heated to the specified asphalt mixture mixing temperature. The asphalt mixture mixing plant is preheated to about 10°C above the mixing temperature. The preheated coarse and fine mineral aggregates are placed in the mixing plant and mixed for 90 seconds. Then, the required amount of asphalt heated to the mixing temperature is added, and the mixing plant is started and mixed for 60 seconds. After that, mixing is paused, and mineral powder heated to the mixing temperature and wide-temperature-range multi-stage phase change material are added. Mixing continues until homogeneous, thus obtaining a wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture. The prepared wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture is maintained within the required mixing temperature range.

[0078] Subsequently, the required specimens for the experiment were prepared using the mixed wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture. Specifically, the amount of the mixed wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture required for each specimen was weighed evenly, and then molded into the required specimen type according to the experimental requirements. After the specimens were compacted, the sleeve and base were removed, and the mold containing the specimens was placed horizontally and cooled to room temperature before being placed on a demolding machine to remove the specimens. The specimens were carefully placed on a dry and clean surface and left to stand overnight at room temperature for testing.

[0079] Implementation Case 1: 3% of the wide temperature range multi-stage phase change material prepared in Example 2 (as a percentage of the total mass of the asphalt mixture) was incorporated into AC-13 type asphalt mixture. The mix proportions of the asphalt mixture are shown in Table 1.

[0080] Table 1 Asphalt Mixture Proportioning

[0081]

[0082] Implementation Case 2: 4% of the wide temperature range multi-stage phase change material prepared in Example 2 (as a percentage of the total mass of the asphalt mixture) was incorporated into AC-13 type asphalt mixture. The mix proportions of the asphalt mixture are shown in Table 1.

[0083] Implementation Case 3: 5% of the wide-temperature-range multi-stage phase change material prepared in Example 2 (as a percentage of the total mass of the asphalt mixture) was incorporated into AC-13 type asphalt mixture. The mix proportions of the asphalt mixture are shown in Table 1.

[0084] The sample without the addition of a wide-temperature-range multi-stage phase change material was used as a control group. It should be noted that the specimens prepared using the materials of Implementation Case 1, Implementation Case 2, Implementation Case 3 and the reference group had the same dimensions.

[0085] The performance of different implementation cases is shown in Table 2. The temperature regulation effect was tested through indoor temperature regulation tests. The temperature rise curves of different asphalt mixtures and the temperature difference curves between them and ordinary asphalt mixtures are shown in Table 2. Figure 3 As shown.

[0086] Experimental results show that the wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture prepared using the method of this invention significantly improves the rutting resistance of asphalt mixtures, with generally similar improvement effects across different implementation cases. Furthermore, the temperature regulation test results demonstrate that, compared to ordinary asphalt mixtures, the wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture prepared using the method of this invention exhibits a slower heating rate, effectively delaying the occurrence of the highest temperature, and showing a significant temperature difference. The maximum temperature differences were recorded as -16℃ (Example 3), -15℃ (Example 2), and -14℃ (Example 1), respectively. A large temperature difference directly reflects its cooling effect, effectively reducing pavement temperature. Lower pavement temperatures result in better load-bearing capacity and deformation resistance, and lower pavement temperatures also help alleviate the urban heat island effect.

[0087] Table 2 Results of Hamburg rutting tests on different samples

[0088] Sample Rut depth (mm) AC-13 type asphalt mixture 14.55 Implementation Case 1 3.24 Implementation Case 2 3.43 Implementation Case 3 3.54

[0089] The above experiments show that the wide-temperature-range multi-stage phase change material introduced into the asphalt mixture using the method of the present invention can achieve the effect of buffering the temperature rise of the road surface in summer, prolonging the occurrence time of the daily maximum temperature, and reducing the surface temperature of the road surface.

[0090] The wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture prepared using the method of this invention, due to the introduction of a multi-stage phase change system, exhibits the characteristic of stepwise phase change, enabling it to continuously and efficiently exert its latent heat regulation function within the temperature range of 30–70℃. The wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture of this invention changes at a more stable rate during temperature variations, reducing damage to the pavement structure caused by drastic temperature fluctuations. Especially during seasonal transitions when temperature differences are significant, the wide-temperature-range multi-stage phase change material provided by this invention can effectively absorb and release heat, reducing pavement expansion and contraction caused by temperature differences, preventing cracks and surface damage, and improving the overall performance of the pavement.

[0091] The wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture of this invention can effectively reduce the urban heat island effect by reducing the heat radiation and heat absorption of the road surface during high-temperature periods. Especially in summer, by reducing the impact of road surface temperature on the surrounding air temperature, it can alleviate the problem of excessively high temperatures in urban centers, thereby improving the quality of the urban ecological environment. In addition, the reusability and long service life of phase change materials also make this technology highly environmentally friendly and economically beneficial.

[0092] This invention, through the application of wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture technology, can improve the performance of asphalt pavements in multiple aspects. It not only improves temperature control and extends pavement life, but also effectively addresses issues such as the urban heat island effect, enhances road safety, and reduces maintenance costs. These advantages make this technology promising for widespread application and significant economic benefits in modern transportation infrastructure.

[0093] In the several embodiments provided by this invention, it should be understood that the apparatus and methods disclosed in this invention can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For example, the division of modules is merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0094] Furthermore, the functional modules in the various embodiments of the present invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated module can be implemented in hardware or in the form of hardware plus software functional modules.

[0095] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture, characterized in that, include: S1: Prepare various composite organic eutectic phase change materials respectively; S2: The various composite organic eutectic phase change materials are compounded in different proportions to obtain a wide-temperature-range multi-stage phase change material; S3: The wide-temperature-range multi-stage phase change material is incorporated into the asphalt mixture at a mass ratio of 3% to 5% to form the wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture. The various composite organic eutectic phase change materials include CPCM1, CPCM2, CPCM3, CPCM4, CPCM5, CPCM6, and CPCM7, among which... The raw materials of the CPCM1 composite organic eutectic phase change material are 133-173 parts by mass of palmitic acid, 223-263 parts by mass of myristic acid, 584-624 parts by mass of methyl stearate and 90-110 parts by mass of expanded graphite. The raw materials for the CPCM2 composite organic eutectic phase change material are 128-168 parts by mass of palmitic acid, 832-872 parts by mass of methyl stearate, and 90-110 parts by mass of expanded graphite. The raw materials of the CPCM3 composite organic eutectic phase change material are 180-220 parts by weight of stearic acid, 270-330 parts by weight of palmitic acid, 440-540 parts by weight of myristic acid, and 90-110 parts by weight of expanded graphite. The raw materials of the CPCM4 composite organic eutectic phase change material are 105-145 parts by mass of butyramide, 855-895 parts by mass of myristic acid, and 90-110 parts by mass of expanded graphite. The raw materials for the CPCM5 composite organic eutectic phase change material are 360-440 parts by weight of stearic acid, 540-660 parts by weight of palmitic acid, and 90-110 parts by weight of expanded graphite. The raw materials of the CPCM6 composite organic eutectic phase change material are 121-161 parts by mass of butyramide, 839-879 parts by mass of palmitic acid, and 90-110 parts by mass of expanded graphite. The raw materials for the CPCM7 composite organic eutectic phase change material are 134-174 parts by mass of butyramide, 826-866 parts by mass of stearic acid, and 90-110 parts by mass of expanded graphite.

2. The method for preparing wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture according to claim 1, characterized in that, The preparation process of the CPCM1 composite organic eutectic phase change material includes: 133-173 parts by weight of palmitic acid, 223-263 parts by weight of myristic acid, and 584-624 parts by weight of methyl stearate are heated until completely melted and stirred thoroughly to form a blended mixture. Add 90-110 parts by mass of expanded graphite to the blended mixture, stir and adsorb under vacuum at 70-90°C for 4-6 hours, and then place it in a vacuum drying oven to continue adsorption for 40-55 hours. The adsorption-completed mixture was removed, rinsed repeatedly with anhydrous ethanol, and then dried in an oven to obtain the CPCM1 composite organic eutectic phase change material.

3. The method for preparing wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture according to claim 2, characterized in that, The preparation process of the CPCM2 composite organic eutectic phase change material includes: 128-168 parts by weight of palmitic acid and 832-872 parts by weight of methyl stearate are heated until completely melted and stirred thoroughly to form a blended mixture. 90-110 parts by weight of expanded graphite are added to the blended mixture, and the mixture is stirred and adsorbed under vacuum at 70-90°C for 4-6 hours. Then, it is placed in a vacuum drying oven for further adsorption for 40-55 hours. The adsorbed mixture is taken out, rinsed repeatedly with anhydrous ethanol, and dried in an oven to obtain the CPCM1 composite organic eutectic phase change material.

4. The method for preparing wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture according to claim 2, characterized in that, S2 includes: A wide-temperature-range multi-stage phase change material is obtained by mixing CPCM1 composite organic eutectic phase change material (2-8% by mass), CPCM2 composite organic eutectic phase change material (17-23% by mass), CPCM3 composite organic eutectic phase change material (27-33% by mass), CPCM4 composite organic eutectic phase change material (17-23% by mass), CPCM5 composite organic eutectic phase change material (7-13% by mass), CPCM6 composite organic eutectic phase change material (7-13% by mass), and CPCM7 composite organic eutectic phase change material (2-8% by mass).

5. The method for preparing wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture according to claim 1, characterized in that, The asphalt mixture includes mineral aggregates, mineral powder, and asphalt, and S3 includes: Dry mineral aggregates of various specifications for later use, and melt asphalt and heat it to the specified asphalt mixture mixing temperature for later use. Preheat the asphalt mixture mixing plant to a predetermined temperature above the required mixing temperature, and then place the various sizes of mineral aggregates into the asphalt mixture mixing plant for mixing. Add the required asphalt, heated to the mixing temperature, to the asphalt mixture mixing plant and continue mixing. Then pause mixing and add mineral powder and wide-temperature-range multi-stage phase change material, both heated to the mixing temperature, to the asphalt mixture mixing plant. Continue mixing until the mixture is homogeneous to obtain the wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture.

6. The method for preparing wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture according to claim 5, characterized in that, The asphalt is SBS polymer-modified asphalt.

7. The method for preparing wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture according to claim 5, characterized in that, S3 further includes: Before use, the prepared wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture should be kept within the predetermined mixing temperature range.

8. A wide-temperature-range multi-stage phase change temperature-regulating asphalt mixture, characterized in that, Prepared using the preparation method according to any one of claims 1 to 7.

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