Asphalt modifier, modified asphalt, asphalt mixture and preparation method and application thereof

Abstract

The invention discloses an asphalt modifier, modified asphalt, an asphalt mixture and a preparation method and application thereof. The asphalt modifier comprises the following raw material components in percentage by weight: 30%-34% of thermoplastic rubber, 22%-28% of resin, 5%-10% of a dispersing agent, 1%-3% of a cross-linking agent and 28%-35% of oil, wherein the percentage is the mass percentage of each component in the asphalt modifier. The modified asphalt prepared by adopting the asphalt modifier disclosed by the invention can be used for remarkably reducing the mixing and construction temperature of an asphalt mixture, saving energy, reducing the emission of harmful gases and improving the pavement performance of the asphalt mixture.

Description

Technical Field

[0001] This invention relates to an asphalt modifier, modified asphalt, asphalt mixture, its preparation method, and its application. Background Technology

[0002] Asphalt pavement is currently the primary type of highway pavement, accounting for over 90% of all highway construction. In new expressway projects, the proportion of asphalt pavement structures approaches 100%. However, the vast majority of asphalt pavement construction in China uses traditional hot-mix asphalt mixtures, with mixing temperatures exceeding 160℃. These extremely high temperatures not only lead to significant energy consumption but also release large amounts of harmful gases and dust particles, severely impacting sustainable development and environmental protection. Furthermore, excessively high temperatures easily cause asphalt aging, significantly affecting its road performance. The high-temperature production and construction environment of hot-mix asphalt mixtures, especially in tunnels and relatively enclosed spaces, exacerbates the harm to construction workers from the harmful gases and dust particles, severely damaging their physical and mental health. In addition, hot-mix asphalt mixtures have strict requirements regarding construction temperature.

[0003] Although research on warm mix asphalt and warm mix asphalt (WMA) was conducted in Europe and the United States in the late 1990s to reduce the mixing temperature of asphalt, and the problems of high energy consumption and high emissions of dust and harmful gases in the production process were solved by reducing the mixing temperature, warm mix asphalt (WMA) produced by existing technology still has significant differences in road performance compared with traditional hot mix asphalt. Summary of the Invention

[0004] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies where warm-mix asphalt mixtures still exhibit significant differences in road performance compared to traditional hot-mix asphalt. This invention provides an asphalt modifier, modified asphalt, asphalt mixture, its preparation method, and its application. The asphalt mixture described in this invention, when applied, not only reduces mixing and construction temperatures, saves energy, and reduces emissions of toxic and harmful gases such as asphalt fumes, but also improves the road performance of the asphalt mixture.

[0005] The present invention solves the above-mentioned technical problems through the following technical solution:

[0006] This invention discloses an asphalt modifier, the raw materials of which contain the following components in the following proportions:

[0007] 30%-34% thermoplastic rubber, 22%-28% resin, 5%-10% dispersant, 1%-3% crosslinking agent and 28%-35% oil;

[0008] The percentage refers to the mass percentage of each component in the asphalt modifier.

[0009] In this invention, the thermoplastic rubber can be a conventional thermoplastic rubber used for asphalt modification in the art, preferably thermoplastic styrene-butadiene rubber (SBS), also known as styrene-butadiene-styrene block copolymer, and more preferably a linear thermoplastic styrene-butadiene rubber.

[0010] In this invention, the content of the thermoplastic rubber is preferably 31%-33%, for example 32%.

[0011] In this invention, the resin may be at least one of petroleum resin, bio-based resin, and composite resin thereof.

[0012] Preferably, the resin is selected from one or more of C5 petroleum resin, C9 petroleum resin, C5 / C9 copolymer resin, hydrogenated petroleum resin, terpene resin, and terpene-C5 composite resin. The terpene-C5 composite resin refers to a composite resin formed by terpene resin and C5 petroleum resin.

[0013] In this invention, the resin content is preferably 23%-26%, for example 25%.

[0014] In this invention, the dispersant may be a surfactant with good emulsifying and low-temperature dispersing ability, preferably including lecithin or its derivatives, more preferably soybean lecithin or its derivatives.

[0015] In this invention, the content of the dispersant is preferably 6%-9%, for example 8%.

[0016] In this invention, the crosslinking agent can be a commonly used crosslinking agent for polymer materials in the art, preferably an organic peroxide.

[0017] The half-life parameters of the organic peroxide preferably satisfy the following: half-life ≤ 1 min at 120-160℃, and half-life temperature ≥ 75℃ at 10 h.

[0018] In this invention, the crosslinking agent is preferably dicumyl peroxide. The dicumyl peroxide is generally industrial-grade dicumyl peroxide with a purity ≥ 95%.

[0019] In this invention, the content of the crosslinking agent is preferably 1.5%-2.5%, for example 2%.

[0020] In this invention, the oil can be a commonly used vegetable oil or modified vegetable oil in the art, preferably corn oil.

[0021] Preferably, the vegetable oil or modified vegetable oil meets the following requirements: octadecenoic acid content ≥70% and iodine value ≥120mg / g.

[0022] In this invention, the oil is preferably corn oil. Preferably, the corn oil meets the following requirements: octadecenoic acid content ≥ 70% and iodine value ≥ 120 mg / g. For example, the corn oil meets the following requirements: octadecenoic acid content 72% and iodine value 120 mg / g.

[0023] In this invention, the oil content is preferably 30%-34%, for example 33%.

[0024] In some preferred embodiments of the present invention, the raw materials of the asphalt modifier contain the following components in the following proportions: 30%-34% of linear thermoplastic styrene-butadiene rubber, 22%-28% of terpene-C5 composite resin, 5%-10% of soybean lecithin, 1%-3% of dicumyl peroxide and 28%-35% of corn oil, wherein the percentages are the mass percentages of each component in the asphalt modifier.

[0025] In some preferred embodiments of the present invention, the raw materials of the asphalt modifier contain the following components in the following proportions: 32% thermoplastic rubber, 25% resin, 8% dispersant, 2% crosslinking agent and 33% oil, wherein the percentages are the mass percentages of each component in the asphalt modifier.

[0026] In some specific embodiments of the present invention, the raw materials of the asphalt modifier contain the following components in the following proportions: 32% linear SBS, 25% terpene-C5 composite resin, 8% soybean lecithin, 2% dicumyl peroxide and 33% corn oil, wherein the percentages are the mass percentages of each component in the asphalt modifier.

[0027] The present invention also provides a method for preparing the asphalt modifier, which includes the following steps:

[0028] The thermoplastic rubber and the oil are premixed, and the resin and the dispersant are added for blending. Then, the crosslinking agent is added for crosslinking to prepare the asphalt modifier.

[0029] In this invention, the premixing method is stirring.

[0030] In this invention, the premixing temperature is preferably 115℃-125℃, for example, 120℃. Under this temperature condition, the thermoplastic rubber and the oil swell.

[0031] In this invention, the premixing time is preferably 2 hours or more, for example, 2 hours.

[0032] In this invention, the blending method is shearing.

[0033] The shearing temperature is 155℃-165℃, for example, 160℃.

[0034] The shearing speed is 3000rpm-3500rpm, for example, 3000rpm.

[0035] The cutting time is 30 minutes or more, for example, 30 minutes.

[0036] In this invention, the crosslinking temperature is 95℃-105℃, for example, 100℃.

[0037] In this invention, preferably, stirring is performed during the crosslinking process.

[0038] The stirring speed is preferably 200 rpm to 500 rpm.

[0039] The stirring time is 10 minutes or more, for example, 10 minutes.

[0040] In this invention, the crosslinking process preferably includes a cooling step.

[0041] The cooling rate is preferably ≥10℃ / min.

[0042] Preferably, the cooling temperature is below 60°C.

[0043] The present invention also provides a modified asphalt, the raw materials of which include the following components:

[0044] 93%-97% SBS modified bitumen and 3%-7% of the bitumen modifier;

[0045] The percentage refers to the percentage of each component by mass of the modified asphalt.

[0046] In this invention, the SBS modified asphalt can be conventional SBS modified asphalt in the art.

[0047] In some preferred embodiments of the present invention, the raw materials for the modified asphalt include 97% SBS modified asphalt and 3% of the asphalt modifier.

[0048] The present invention also provides a method for preparing the modified asphalt, which includes the following steps:

[0049] The asphalt modifier is heated and then mixed and stirred with the SBS modified asphalt to obtain the modified asphalt.

[0050] In this invention, the purpose of heating the asphalt modifier is to bake it.

[0051] In this invention, the heating temperature of the asphalt modifier can be above 80°C, preferably 90-100°C.

[0052] In this invention, the preferred temperature for the SBS modified asphalt is 120–135°C.

[0053] In this invention, the mixing and stirring can be carried out using conventional stirring methods in the art, and can be performed in a mechanical stirring device.

[0054] In this invention, the mixing speed is 500-800 rpm, for example 650 rpm.

[0055] In this invention, the mixing and stirring time is 30 minutes or more, for example, 40 minutes.

[0056] In some embodiments of the present invention, the method for preparing the modified asphalt includes the following steps: heating the asphalt modifier at 90-100°C, heating the SBS modified asphalt to a temperature of 120-135°C, and then mixing and stirring at a speed of 300-600 rpm for more than 30 minutes.

[0057] This invention also discloses a modified asphalt mixture comprising the following components:

[0058] Minerals, the modified bitumen, and cenospheres;

[0059] The modified asphalt content is 3%-6%, and the cenosphere content is 4%-8%, with the percentages representing the mass percentage of each component relative to the mineral material.

[0060] In this invention, the float beads can be conventional float beads in the art.

[0061] In this invention, the content of the cling beads is preferably 5%-7%, for example 6%.

[0062] In this invention, the content of the modified bitumen is preferably 3%-5%, for example 4%.

[0063] In this invention, the mineral material can be a conventional mineral material in the art.

[0064] In some embodiments of the present invention, the mineral material includes aggregate and mineral powder. The mineral powder is preferably limestone mineral powder. The preferred mass ratio of the aggregate to the mineral powder is (94-97):(3-6).

[0065] The present invention also provides a method for preparing the modified asphalt mixture, which includes the following steps: mixing the aggregate, the modified asphalt and the cenospheres evenly.

[0066] In this invention, the mixing can be carried out in a conventional mixing container in the art, preferably in a mixing pot.

[0067] In this invention, before mixing, the mineral material is kept at a temperature above 150°C for more than 4 hours, for example, kept at 150°C for 4 hours.

[0068] In this invention, before mixing, the modified asphalt is heated to 120-140°C, for example, 130°C or 135°C.

[0069] In this invention, the mixing temperature is 120-140℃, for example, 130℃.

[0070] In some preferred embodiments of the present invention, the mineral material includes aggregates and mineral powder, and the method for preparing the asphalt mixture includes: first mixing the aggregates, second mixing with a portion of the modified asphalt, third mixing with the cenospheres, fourth mixing with the remaining portion of the modified asphalt, and finally fifth mixing with the mineral powder.

[0071] The mixing time for the first mixing is preferably 90 seconds or more, for example, 90 seconds.

[0072] The mixing time for the second mixing is preferably 30 seconds or more, for example, 30 seconds.

[0073] The third mixing time is preferably 30 seconds or more, for example, 30 seconds.

[0074] The fourth mixing time is preferably 60 seconds or more, for example, 60 seconds.

[0075] The fifth mixing time is preferably 90 seconds or more, for example, 90 seconds.

[0076] Preferably, the modified asphalt portion is half of the modified asphalt.

[0077] In some specific embodiments of the present invention, the mineral material includes aggregates and mineral powder, and the preparation method of the asphalt mixture includes: mixing the aggregates for 90 seconds, adding half of the modified asphalt and mixing for 30 seconds, adding the cenospheres and mixing for 30 seconds, then adding the remaining modified asphalt, and finally adding the mineral powder and mixing for 90 seconds.

[0078] The present invention also provides an application of the asphalt mixture in road paving structures.

[0079] In this invention, the asphalt mixture can be used for the laying or repair of road paving structures, and is especially suitable for road surfaces in cold regions.

[0080] The positive and progressive effects of this invention are as follows:

[0081] This invention, through the component design of asphalt modifiers and their compounding with SBS modified asphalt, and further through the addition of cenospheres, significantly reduces the mixing and construction temperature of asphalt mixtures, thus solving the industry problem of energy conservation and reducing the emission of toxic and harmful gases such as asphalt fumes. At the same time, it can also improve the road performance of asphalt mixtures, so that the asphalt mixtures produced meet the standards of traditional hot-mix asphalt in terms of high-temperature stability, low-temperature crack resistance, and durability, and significantly exceed the road performance of warm-mix asphalt in the prior art. Detailed Implementation

[0082] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0083] The aggregate used in the following examples and comparative examples is AC-20 type aggregate. The specific gradation composition of AC-20 type aggregate is shown in Table 1.

[0084] Table 1

[0085]

[0086] a It is expressed in terms of the aperture diameter of the square hole sieve.

[0087] b Mass percentage refers to the proportion of components that pass through the corresponding square-hole sieve.

[0088] The manufacturers or models of the raw materials used in the following examples and comparative examples are shown in Table 2.

[0089] Table 2 Sources of each raw material

[0090]

[0091] Examples 1-1 to 1-3 and Comparative Example 1-1: Preparation of Asphalt Modifier

[0092] Example 1-1:

[0093] The raw materials for the asphalt modifier contain the following components: 32% linear SBS, 25% terpene-C5 composite resin, 8% soybean lecithin, 2% dicumyl peroxide, and 33% corn oil. The percentages represent the mass percentage of each component in the asphalt modifier. The corn oil contains 72% octadecenoic acid and has an iodine value of 120 mg / g; the purity of dicumyl peroxide is ≥95%.

[0094] The preparation method of asphalt modifier includes the following steps:

[0095] (1) Premixing: Linear SBS and corn oil are stirred and swollen at 120°C for 2 hours;

[0096] (2) Blending; add terpene-C5 composite resin and soybean lecithin, heat to 160℃ and shear at 3000rpm for 30 minutes;

[0097] (3) Crosslinking: Cool to 100℃, add dicumyl peroxide, and stir at 200 rpm for 10 minutes to carry out crosslinking;

[0098] (4) Cooling: After the cross-linking is completed, the system is cooled to below 60°C at a cooling rate of 10°C / min to complete the molding and obtain the asphalt modifier.

[0099] Examples 1-2

[0100] The only difference between Examples 1-2 and Examples 1-1 is that, instead of corn oil, aromatic oil is used; the other steps and parameters are the same as in Example 1-1.

[0101] Examples 1-3

[0102] The only difference between Examples 1-3 and Example 1-1 is that C5 petroleum resin is used instead of terpene-C5 composite resin. All other steps and parameters are the same as in Example 1-1.

[0103] Comparative Example 1-1

[0104] The only difference between Comparative Example 1-1 and Example 1-1 is that the crosslinking agent dicumyl peroxide is not used; all other steps and parameters are the same as in Example 1-1.

[0105] Examples 2-1 to 2-5, Comparative Examples 2-1 to 2-2: Preparation of Modified Asphalt

[0106] Example 2-1:

[0107] The raw materials for modified asphalt contain the following components: 97% SBS modified asphalt and 3% asphalt modifier prepared in Example 1-1, wherein the percentages are the mass percentages of each component in the modified asphalt.

[0108] The preparation method of modified asphalt includes the following steps: baking the asphalt modifier at 95°C, then adding the baked asphalt modifier to SBS modified asphalt at 130°C, and stirring at 650 rpm for 40 minutes in a mechanical mixing device to obtain modified asphalt.

[0109] Example 2-2:

[0110] The only difference between Example 2-2 and Example 2-1 is that the amount of asphalt modifier used is 5%, and the amount of SBS modified asphalt used is 95%.

[0111] Examples 2-3:

[0112] The only difference between Example 2-3 and Example 2-1 is that the amount of asphalt modifier is 7% and the amount of SBS modified asphalt is 93%.

[0113] Examples 2-4:

[0114] The only difference between Example 2-4 and Example 2-1 is that the asphalt modifier prepared in Example 1-1 is not used, but the asphalt modifier prepared in Example 1-2 is used. The other steps and parameters are the same as in Example 2-1.

[0115] Examples 2-5:

[0116] The only difference between Examples 2-5 and Examples 2-1 is that the asphalt modifier prepared in Example 1-1 is not used, but the asphalt modifier prepared in Example 1-3 is used. The other steps and parameters are the same as in Example 2-1.

[0117] Comparative Example 2-1

[0118] The only difference between Comparative Example 2-1 and Example 2-1 is that the asphalt modifier prepared in Comparative Example 1-1 is used instead of the asphalt modifier prepared in Example 1-1. All other steps and parameters are the same as in Example 2-1.

[0119] Comparative Example 2-2:

[0120] The only difference between Comparative Example 2-2 and Example 2-1 is that the asphalt modifier prepared in Example 1-1 is not used, but the commercially available Sasobit warm mix modifier is used. All other steps and parameters are the same as in Example 2-1.

[0121] Examples 3-1 to 3-11 and Comparative Examples 3-1 to 3-6: Preparation of Modified Asphalt Mixtures

[0122] Example 3-1:

[0123] Modified asphalt mixtures were prepared using the modified asphalt, cenospheres, and aggregates obtained in Example 2-1. The aggregates consisted of aggregates and mineral powder in a mass ratio of 97:3. The aggregates were AC-20 type aggregates, and the mineral powders were limestone mineral powder. The modified asphalt content was 4% of the aggregate mass, and the cenospheres content was 4% of the aggregate mass.

[0124] The preparation method of modified asphalt mixture includes the following steps:

[0125] S1. Pretreatment: After the AC-20 graded aggregate is kept in an oven at 150 ℃ for 4 h, it is taken out; the modified asphalt is heated to 140 ℃ and kept at that temperature for 30 min.

[0126] S2. Mixing: Add the pretreated aggregate to the mixing pot and mix for 90 seconds. Then add half of the pretreated modified asphalt and mix for 30 seconds. Next, add the cenospheres and mix for 30 seconds. Then add the remaining half of the pretreated modified asphalt and mix for 60 seconds. Finally, add the limestone powder and continue mixing for 90 seconds. Maintain the temperature at 140℃ throughout the process to obtain the modified asphalt mixture.

[0127] Example 3-2:

[0128] The only difference between Example 3-2 and Example 3-1 is that the amount of cenospheres used in S2 is 6% of the mineral mass, while the other steps and conditions are the same as in Example 3-1.

[0129] Example 3-3:

[0130] The only difference between Example 3-3 and Example 3-1 is that the amount of cenospheres used in S2 is 8% of the mineral mass, while the other steps and conditions are the same as in Example 3-1.

[0131] Examples 3-4:

[0132] The difference between Examples 3-4 and Example 3-1 is that the modified asphalt is the modified asphalt prepared in Example 2-4, while the remaining steps and conditions are the same as in Example 3-1.

[0133] Examples 3-5:

[0134] The difference between Examples 3-5 and Example 3-1 is that the modified asphalt is the modified asphalt prepared in Example 2-5, while the remaining steps and conditions are the same as in Example 3-1.

[0135] Examples 3-6:

[0136] The difference between Examples 3-6 and Example 3-1 is that the modified asphalt used is not the modified asphalt prepared in Example 2-1, but the modified asphalt prepared in Example 2-2. In step S1, the modified asphalt is heated to 130°C, and in step S2, it is kept at 130°C throughout. The remaining steps and conditions are the same as in Example 3-1.

[0137] Examples 3-7:

[0138] The only difference between Examples 3-7 and Examples 3-6 is that the amount of cenospheres used in S2 is 6% of the mineral mass, while the other steps and conditions are the same as in Examples 3-6.

[0139] Examples 3-8:

[0140] The only difference between Examples 3-8 and Examples 3-6 is that the amount of cenospheres used in S2 is 8% of the mineral mass, while the other steps and conditions are the same as in Examples 3-6.

[0141] Examples 3-9:

[0142] The difference between Examples 3-9 and Example 3-1 is that the modified asphalt used is not the modified asphalt prepared in Example 2-1, but the modified asphalt prepared in Example 2-3. In step S1, the modified asphalt is heated to 120°C, and in step S2, it is kept at 120°C throughout. The remaining steps and conditions are the same as in Example 3-1.

[0143] Examples 3-10:

[0144] The only difference between Examples 3-10 and Examples 3-9 is that the amount of cenospheres used in S2 is 6% of the mineral mass, while the other steps and conditions are the same as in Examples 3-9.

[0145] Example 3-11:

[0146] The only difference between Example 3-11 and Example 3-9 is that the amount of cenospheres used in S2 is 8% of the mineral mass, while the other steps and conditions are the same as in Example 3-9.

[0147] Comparative Example 3-1:

[0148] The only difference between Comparative Example 3-1 and Example 3-1 is that the modified asphalt is the modified asphalt prepared in Comparative Example 2-1, while the other steps and conditions are the same as in Example 3-1.

[0149] Comparative Example 3-2:

[0150] The only difference between Comparative Example 3-2 and Example 3-1 is that the modified asphalt is the modified asphalt prepared in Comparative Example 2-2, while the other steps and conditions are the same as in Example 3-1.

[0151] Comparative Example 3-3:

[0152] The only difference between Comparative Example 3-1 and Example 3-1 is that no float beads are used in S2, while the other steps and conditions are the same as in Example 3-1.

[0153] Comparative Examples 3-4:

[0154] The only difference between Comparative Examples 3-5 and Examples 3-6 is that no float beads are used in S2; the other steps and conditions are the same as in Examples 3-6.

[0155] Comparative Examples 3-5:

[0156] The only difference between Comparative Example 3-3 and Example 3-9 is that no float beads are used in S2, while the other steps and conditions are the same as in Example 3-9.

[0157] Comparative Examples 3-6:

[0158] Modified asphalt mixtures were prepared using commercially available SBS modified asphalt and aggregates. The aggregates consisted of aggregates and mineral powder in a mass ratio of 97:3. The aggregates were AC-20 type aggregates, and the mineral powders were limestone mineral powders. The modified asphalt content was 4% of the aggregate mass.

[0159] The traditional method for preparing hot-mix asphalt mixtures includes the following steps:

[0160] After the AC-20 aggregate was kept in an oven at 180℃ for 4 hours, it was taken out and added to a mixing pot and mixed for 90 seconds. Then, commercially available SBS modified asphalt was added and mixed for 90 seconds. Finally, limestone mineral powder was added and stirred evenly for 90 seconds. The temperature was maintained at 165℃ throughout the process to obtain a traditional hot-mix asphalt mixture.

[0161] Example 1

[0162] Performance of modified asphalt

[0163] The performance of commercially available SBS modified asphalt, modified asphalt AC-20 prepared in Examples 2-1 to 2-5, and comparative examples 2-1 and 2-2 was tested according to conventional methods in the art. The test was conducted in accordance with the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" JTG E20-2011, as shown in Table 3. The test results are shown in Table 4.

[0164] Table 3: Test Basis for Modified Asphalt Performance

[0165]

[0166] Table 4 Performance Analysis of Modified Asphalt

[0167]

[0168] As shown in Table 4, the modified asphalt prepared in Example 2-1, compared with commercially available SBS modified asphalt, exhibits a significant improvement in viscosity: at 135 °C, the viscosity decreased from 2.901 Pa·s to 0.963 Pa·s, a reduction of approximately 67%; at 155 °C, it decreased from 1.245 Pa·s to 0.426 Pa·s, a reduction of approximately 66%; and at 175 °C, it decreased from 0.679 Pa·s to 0.253 Pa·s, a reduction of approximately 63%. This indicates a substantial improvement in high-temperature flowability, allowing for a reduction in mixing temperature of approximately 25 °C to 40 °C. Simultaneously, its low-temperature workability was also enhanced: penetration increased from 5.4 mm to 7.38 mm, ductility increased from 32.4 cm to 34.7 cm, and the softening point slightly increased by 1.4 °C.

[0169] As can be seen from the data in Examples 2-2 and 2-3, as the amount of modifier increased from 3% to 5% and 7%, the viscosity at 135 °C further decreased to 0.778 Pa·s and 0.768 Pa·s, and the ductility decreased to 24.6 cm and 20.7 cm, respectively.

[0170] The viscosity, softening point, and ductility of Comparative Example 2-1 (modified asphalt prepared using an asphalt modifier without crosslinking agent) and Comparative Example 2-2 (modified asphalt prepared using commercially available Sasobit warm mix agent) were all lower than those of Example 2-1, indicating that the asphalt modifier prepared in Example 2-1 used in this invention has better overall performance in terms of balancing low-temperature construction and high-temperature stability.

[0171] Compared with Example 2-1, Examples 2-4 and 2-5 replaced the asphalt modifier with the modifiers prepared in Examples 1-2 (replacing corn oil with aromatic oil) and 1-3 (replacing terpene-C5 composite resin with C5 petroleum resin), respectively. The high-temperature fluidity and low-temperature ductility decreased slightly: the viscosity at 135 °C increased from 0.96 Pa·s in Example 2-1 to about 1.25 Pa·s (Example 2-4) and 1.08 Pa·s (Example 2-5), the ductility decreased from 34.7 cm to 28.3 cm and 29.0 cm, and the softening point also decreased slightly. However, the performance of both examples was still significantly better than that of the comparative example group using commercial warm mix modifier (Comparative Example 2-2) or Comparative Example 1-1 modifier. They maintained a significant advantage in viscosity at 135 °C and 175 °C and low-temperature ductility, effectively verifying the stability and comprehensive performance of the modifier system of the present invention.

[0172] Example 2

[0173] Performance of modified asphalt mixtures

[0174] The modified asphalt mixtures prepared in Examples 3-1 to 3-11 and Comparative Examples 3-1 to 3-6 were tested for performance according to conventional methods in the art. The test items, index requirements and test methods are shown in Table 5. The index requirements are from "Warm Mix Asphalt Concrete" (GB / T 30596-2014) and "Low Temperature Modified Asphalt" (JT / T 1540-2025).

[0175] The measured performance values ​​of the modified asphalt mixture AC-20 prepared in Examples 3-1 to 3-11 and Comparative Examples 3-1 to 3-6 are shown in Table 6.

[0176] Table 5 Technical Standards

[0177]

[0178] Table 6 Performance Analysis of Modified Asphalt Mixtures

[0179]

[0180] According to Table 6, the effects of changes in each component are as follows:

[0181] In Examples 3-2 and 3-3, when the amount of cenospheres was increased from 4% to 6% and 8%, the stability increased from 10.8 kN to 11.1 kN and 11.5 kN, the freeze-thaw splitting strength ratio remained around 88.1% and 86.6%, the rutting dynamic stability increased from 3944.7 cycles / mm to 4013.2 cycles / mm and 4131.7 cycles / mm, and the failure strain in the -10℃ low-temperature bending test decreased slightly from 2833.4 με to 2801.3 με and 2797.6 με. This demonstrates that the change in the amount of cenospheres significantly improves high-temperature stability and has little effect on freeze-thaw splitting strength.

[0182] In Examples 3-4, when the modified asphalt was replaced with the aromatic oil-based modifier prepared in Examples 1-2, the stability decreased from 10.8 kN to 10.5 kN, the freeze-thaw splitting strength ratio decreased from 87.8% to 86.2%, the rutting dynamic stability decreased from 3944.7 cycles / mm to 3811.0 cycles / mm, and the failure strain in the -10℃ low-temperature bending test decreased from 2833.4 με to 2789.5 με. This demonstrates that changing corn oil to aromatic oil reduced high-temperature stability and low-temperature toughness.

[0183] In Examples 3-5, when the modified asphalt was replaced with the C5 petroleum resin-based modifier prepared in Examples 1-3, the stability decreased from 10.8 kN to 10.3 kN, the freeze-thaw splitting strength ratio decreased from 87.8% to 85.7%, the rutting dynamic stability decreased from 3944.7 cycles / mm to 3765.4 cycles / mm, and the failure strain in the -10℃ low-temperature bending test decreased from 2833.4 με to 2702.4 με. This demonstrates that changing the resin phase from terpene-C5 composite resin to C5 petroleum resin further reduced the high-temperature load-bearing capacity and low-temperature toughness of the mixture.

[0184] Examples 3-6 show that when the mixing temperature was reduced from 140℃ to 130℃ and the modifier ratio was increased from 3% to 5%, the stability increased from 10.8 kN to 11.0 kN, the freeze-thaw splitting strength ratio increased from 87.8% to 89.6%, the rutting dynamic stability increased from 3944.7 cycles / mm to 4077.6 cycles / mm, and the failure strain in the -10℃ low-temperature bending test increased from 2833.4 με to 2936.4 με. This demonstrates that reducing the mixing temperature and optimizing the modifier dosage comprehensively improved the high-temperature stability, rutting resistance, and low-temperature toughness.

[0185] In Comparative Example 3-1, when the source of the asphalt modifier in the modified asphalt raw material changed from the self-made modifier prepared in Example 2-1 to the crosslinking-free modifier prepared in Comparative Example 1-1, the stability decreased from 10.8 kN to 9.8 kN, the freeze-thaw splitting strength ratio increased from 87.8% to 88.1%, the rutting dynamic stability decreased from 3944.7 cycles / mm to 3711.3 cycles / mm, and the failure strain in the -10℃ low-temperature bending test increased from 2833.4 με to 2834.8 με. This demonstrates that using an asphalt modifier lacking a crosslinking agent reduced high-temperature stability and rutting resistance.

[0186] When the source of the asphalt modifier in the modified asphalt raw material was changed from Example 2-1 to commercially available Sasobit warm mix additive (Comparative Example 3-2), the stability decreased from 10.8 kN to 10.5 kN, the freeze-thaw splitting strength ratio increased from 87.8% to 89.4%, the rutting dynamic stability decreased from 3944.7 cycles / mm to 3767.9 cycles / mm, and the failure strain in the -10℃ low-temperature bending test increased from 2833.4 με to 2849.2 με. This demonstrates that commercially available warm mix additives have a significant impact on the performance of the mixture and it is difficult to simultaneously achieve high-temperature rutting resistance and low-temperature toughness.

[0187] When cenospheres are not used and the source of the asphalt modifier in the modified asphalt raw material remains the same as in Example 2-1 (Comparative Example 3-3), the stability remains at 10.8 kN, the freeze-thaw splitting strength ratio increases from 87.8% to 87.9%, the rutting dynamic stability decreases from 3944.7 cycles / mm to 3756.4 cycles / mm, and the failure strain in the -10℃ low-temperature bending test increases from 2833.4 με to 2871.1 με. This demonstrates that the absence of cenospheres has a significant impact on the performance of the mixture and significantly reduces its resistance to rutting.

[0188] When cenospheres were not used and the source of the asphalt modifier in the modified asphalt raw material was replaced with the asphalt modifier without crosslinking agent prepared in Comparative Example 2-1 (Comparative Example 3-4), the stability decreased from 10.8 kN to 10.2 kN, the freeze-thaw splitting strength ratio decreased from 87.8% to 83.5%, the rutting dynamic stability decreased from 3944.7 cycles / mm to 3124.7 cycles / mm, and the failure strain in the -10℃ low-temperature bending test decreased from 2833.4 με to 2653.8 με. This demonstrates that the absence of cenospheres has a significant impact on the various properties of the mixture, comprehensively reducing high-temperature stability, rutting resistance, and low-temperature toughness. This proves that the simultaneous absence of cenospheres and the lack of crosslinking agent in the asphalt modifier severely weakens the overall performance.

[0189] When cenospheres were not used and the source of the asphalt modifier in the modified asphalt raw material was replaced with the Sasobit warm mix modifier used in Comparative Example 2-2 (Comparative Example 3-5), the stability decreased from 10.8 kN to 10.9 kN, the freeze-thaw splitting strength ratio decreased from 87.8% to 81.2%, the rutting dynamic stability decreased from 3944.7 cycles / mm to 3317.6 cycles / mm, and the failure strain in the -10℃ low-temperature bending test decreased from 2833.4 με to 2550.0 με. This demonstrates that the absence of cenospheres has a significant impact on the performance of the mixture, severely weakening the high-temperature stability, rutting resistance, and low-temperature toughness. It also proves that the synergy between cenospheres and the asphalt modifiers prepared in Examples 1-1 to 1-3 is indispensable for improving the overall performance of the mixture.

[0190] When using conventional hot-mix asphalt mixtures (Comparative Examples 3-6), the stability decreased from 10.8 kN to 9.5 kN, the freeze-thaw splitting strength ratio increased from 87.8% to 89.3%, the rutting dynamic stability decreased from 3944.7 cycles / mm to 3834.5 cycles / mm, and the failure strain in the -10℃ low-temperature bending test increased from 2833.4 με to 2848.6 με. This demonstrates that the conventional hot-mix process has a significant impact on the performance of the mixture and cannot simultaneously achieve high-temperature rutting resistance and low-temperature toughness. Therefore, it proves that the modified asphalt and cenosphere synergistic technology of this invention is significantly superior to the conventional hot-mix process.

[0191] Example 3

[0192] Gas emission detection during asphalt mixture mixing process

[0193] To verify the effectiveness of the gas emission testing, the first measurement was conducted after adding the remaining half of the pretreated modified asphalt and mixing for 60 seconds during the asphalt mixture mixing process. A second measurement was then conducted after adding limestone powder. The measurements were performed using a handheld VOCs testing instrument. The instrument was placed inside the asphalt mixture mixing pot, and the maximum gas concentration during mixing was recorded to verify the effect of the modified asphalt. The specific testing method is as follows:

[0194] The VOCs testing instrument is model HYS1000, with a measurement range of 1ppb-2000ppm, manufactured by Zhonghengan. It is equipped with a universal sampling probe that extends into the mixing pot, sampling flue gas at a distance of 30cm from the surface of the mixture. The flue gas is cooled to <40℃ through a heat-resistant extension tube and a condenser module before entering the detector. The sampling flow rate is set to 500 mL / min, and the gas concentration is continuously recorded throughout the entire stirring cycle (60 seconds). The peak value automatically output by the instrument is taken as the maximum value and recorded as the VOCs concentration (MAX value). The results are shown in Table 7.

[0195] Table 7 VOCs Concentration (MAX Value)

[0196]

[0197] As shown in Table 7, the effects of various factors on VOCs concentration (MAX value) in each embodiment and comparative example are as follows:

[0198] When the amount of cenospheres was increased from 4% to 6% (Example 3-2) and 8% (Example 3-3), and the mixing temperature was kept at 140℃, the VOCs concentration (MAX value) measured after adding all the asphalt decreased from 156 mg / mL to 151 mg / mL and 148 mg / mL. After adding mineral powder, the VOCs concentration (MAX value) measured after mixing decreased from 67 mg / mL to 62 mg / mL and 60 mg / mL. This proves that the increase of cenosphere content has a significant impact on VOCs emissions and effectively reduces the VOCs concentration (MAX value) during the construction process of the mixture.

[0199] When the source of the asphalt modifier in the modified asphalt was changed to the aromatic oil-based modifier prepared in Examples 1-2 (Examples 3-4), the mixing temperature was kept at 140℃. After adding all the asphalt, the VOCs concentration (MAX value) was measured to increase from 156 mg / mL to 176 mg / mL. After adding mineral powder, the VOCs concentration (MAX value) was measured to increase from 67 mg / mL to 75 mg / mL. This proves that changing the oil phase from corn oil to aromatic oil has a significant impact on VOC emissions and increases the VOCs concentration (MAX value) during the construction process of the mixture.

[0200] When the source of the asphalt modifier in the modified asphalt was changed to the C5 petroleum resin prepared in Examples 1-3 (Examples 3-5), the mixing temperature was kept at 140°C. After adding all the asphalt, the VOCs concentration (MAX value) was measured to decrease from 156 mg / mL to 149 mg / mL. After adding mineral powder, the VOCs concentration (MAX value) was measured to decrease from 67 mg / mL to 65 mg / mL. This proves that changing the resin phase from terpene-C5 composite resin to C5 petroleum resin has little impact on VOC emissions and slightly reduces the VOCs concentration (MAX value) during the construction process of the mixture.

[0201] When the mixing temperature was reduced from 140℃ to 130℃ and the modifier ratio was increased from 3% to 5% (Examples 3-6), the VOCs concentration (MAX value) measured after adding all the asphalt decreased from 156 mg / mL to 134 mg / mL. After adding mineral powder, the VOCs concentration (MAX value) measured after mixing decreased from 67 mg / mL to 52 mg / mL. This proves that the reduction in mixing temperature and the optimization of asphalt modifier dosage have a significant impact on VOC emissions, and significantly reduce the VOCs concentration (MAX value) during the construction process of the mixture.

[0202] When the amount of cenospheres was increased from 4% to 6% (Examples 3-7) and 8% (Examples 3-8) under the conditions of 130℃ and 5% asphalt modifier ratio, compared with Examples 3-6, the VOCs concentration (MAX value) measured after stirring after adding all the asphalt decreased from 134 mg / mL to 126 mg / mL and 122 mg / mL, and the concentration after adding mineral powder decreased from 52 mg / mL to 48 mg / mL and 43 mg / mL. This proves that under low temperature construction conditions, the increase of cenosphere content has little effect on VOC emissions and slightly reduces the VOCs concentration (MAX value) during the construction process of the mixture.

[0203] When the mixing temperature was reduced from 130℃ to 120℃ and the proportion of asphalt modifier in the modified asphalt was increased from 3% to 7% (Examples 3-9), the VOCs concentration (MAX value) measured after adding all the asphalt decreased from 156 mg / mL to 119 mg / mL. After adding mineral powder, the VOCs concentration (MAX value) measured after stirring decreased from 67 mg / mL to 40 mg / mL. This proves that further reducing the mixing temperature and adjusting the modifier proportion has a significant impact on VOC emissions, and greatly reduces the VOCs concentration (MAX value) during the construction process of the mixture.

[0204] When the amount of cenospheres was increased from 4% to 6% (Examples 3-10) and 8% (Examples 3-11) under the conditions of 120℃ and 7% asphalt modifier in modified asphalt, compared with Examples 3-9, the VOCs concentration (MAX value) measured after stirring after adding all the asphalt decreased from 119 mg / mL in Examples 3-9 to 112 mg / mL and 106 mg / mL, and the concentration decreased from 40 mg / mL to 36 mg / mL and 32 mg / mL after adding mineral powder. This proves that the change in cenosphere content at a lower mixing temperature has a significant impact on VOC emissions, and further reduces the VOCs concentration (MAX value) during the construction process of the mixture.

[0205] In Comparative Example 3-1, the mixing temperature was maintained at 140°C. After adding all the asphalt, the VOC concentration (MAX value) measured by stirring was slightly lower than that in Example 3-1. However, after adding mineral powder, the VOC concentration (MAX value) measured by stirring was slightly higher. This indicates that in the absence of crosslinking agent in the asphalt modifier, the VOC emissions in the asphalt mixing stage were reduced, but the emissions in the mineral powder stage were not significantly improved.

[0206] In Comparative Example 3-2, the operation was also carried out at 140°C. The VOCs concentration (MAX value) measured after adding all the asphalt and stirring was higher than the VOCs concentration (MAX value) measured in Example 3-1. This indicates that the commercially available Sasobit warm mix additive cannot release VOCs during asphalt mixing.

[0207] In Comparative Examples 3-3 to 3-5, the experiments were conducted at 140°C, 130°C, and 120°C, respectively. Since cenospheres were not used, the VOCs concentration (MAX value) measured after adding all the asphalt and stirring in the comparative examples, as well as the VOCs concentration (MAX value) measured after adding mineral powder and stirring, were compared with the maximum values ​​of the examples at the corresponding temperatures. Comparative Examples 3-4 and 3-5 were higher than Examples 3-6 and 3-9, respectively. Only Examples 3-1 and 3-3 at 140°C showed similar VOCs concentrations (MAX values) in the two measurements. This demonstrates that the addition of cenospheres has a significant auxiliary emission reduction effect on the capture and adsorption of VOCs, and this effect increases as the temperature decreases.

[0208] In Comparative Examples 3-6, using the traditional hot-mix process (mixing temperature 165℃), the mixing after adding all the asphalt (mg / mL) and the mixing after adding mineral powder (mg / mL) both reached the highest levels in Comparative Examples 3-1 to 3-6, indicating that omitting the low-temperature modified formulation and cenospheres will significantly increase VOC emissions throughout the construction process.

[0209] In summary, the presence of crosslinking agents in asphalt modifiers, the proportions used in asphalt modifiers, the addition of cenospheres, and the temperature at which modified asphalt with added asphalt modifiers can be used for low-temperature construction all play a crucial role in the effective control of VOC emissions.

[0210] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. An asphalt modifier, characterized in that, Its raw materials contain the following components in the following amounts: 30%-34% thermoplastic rubber, 22%-28% resin, 5%-10% dispersant, 1%-3% crosslinking agent and 28%-35% oil; The percentage refers to the mass percentage of each component in the asphalt modifier.

2. The asphalt modifier according to claim 1, characterized in that, The asphalt modifier satisfies one or more of the following conditions (1)-(12): (1) The thermoplastic rubber is thermoplastic styrene-butadiene rubber, preferably a linear thermoplastic styrene-butadiene rubber; (2) The content of the thermoplastic rubber is 31%-33%, for example 32%; (3) The resin is at least one of petroleum resin, bio-based resin and composite resin, and the resin is preferably selected from one or more of C5 petroleum resin, C9 petroleum resin, C5 / C9 copolymer resin, hydrogenated petroleum resin, terpene resin and terpene-C5 composite resin. (4) The content of the resin is 23%-26%, for example 25%; (5) The dispersant includes lecithin or its derivatives, preferably soybean lecithin or its derivatives; (6) The content of the dispersant is 6%-9%, for example 8%; (7) The crosslinking agent is an organic peroxide, wherein the half-life parameter of the organic peroxide preferably satisfies: half-life ≤ 1 min at 120-160℃ and half-life temperature ≥ 75℃ at 10h; (8) The crosslinking agent is dicumyl peroxide, wherein the dicumyl peroxide is preferably dicumyl peroxide with a purity of ≥95%; (9) The content of the crosslinking agent is 1.5%-2.5%, for example 2%; (10) The oil is a vegetable oil or a modified vegetable oil, wherein the vegetable oil or modified vegetable oil preferably satisfies the following conditions: octadecenoic acid content ≥70% and iodine value ≥120mg / g; (11) The oil is corn oil, wherein the corn oil preferably satisfies the following conditions: octadecenoic acid content ≥70% and iodine value ≥120mg / g; (12) The oil content is 30%-34%, for example 33%.

3. The asphalt modifier according to claim 1, characterized in that, The raw materials of the asphalt modifier contain the following components in the following proportions: 30%-34% of linear thermoplastic styrene-butadiene rubber, 22%-28% of terpene-C5 composite resin, 5%-10% of soybean lecithin, 1%-3% of dicumyl peroxide and 28%-35% of corn oil, wherein the percentages are the mass percentages of each component in the asphalt modifier. Alternatively, the raw materials of the asphalt modifier may contain the following components in the following proportions: 32% thermoplastic rubber, 25% resin, 8% dispersant, 2% crosslinking agent and 33% oil, wherein the percentages are the mass percentages of each component in the asphalt modifier. Preferably, the raw materials of the asphalt modifier contain the following components in the following proportions: 32% linear SBS, 25% terpene-C5 composite resin, 8% soybean lecithin, 2% dicumyl peroxide and 33% corn oil, wherein the percentages are the mass percentages of each component in the asphalt modifier.

4. A method for preparing an asphalt modifier according to any one of claims 1-3, characterized in that, It includes the following steps: The thermoplastic rubber and the oil are premixed, and the resin and the dispersant are added for blending. Then, the crosslinking agent is added for crosslinking to prepare the asphalt modifier.

5. The method for preparing the asphalt modifier according to claim 4, characterized in that, It satisfies one or more of the following conditions (1)-(7): (1) The premixing method is stirring; (2) The premixing temperature is 115℃-125℃, for example 120℃; (3) The premixing time is more than 2 hours, for example, 2 hours; (4) The blending method is shearing, wherein the shearing temperature is preferably 155℃-165℃, for example 160℃; the shearing speed is preferably 3000rpm-3500rpm, for example 3000rpm; and the shearing time is preferably more than 30 minutes, for example 30 minutes. (5) The crosslinking temperature is 95℃-105℃, for example 100℃; (6) Stirring is performed during the crosslinking process, wherein the stirring speed is preferably 200 rpm-500 rpm; the stirring time is preferably 10 minutes or more, for example, 10 minutes; and, (7) The crosslinking process includes a cooling step, wherein the cooling rate is preferably ≥10℃ / min, and the cooling is preferably to below 60℃.

6. A modified asphalt, characterized in that, Its raw materials contain the following components: 93%-97% SBS modified asphalt and 3%-7% asphalt modifier according to any one of claims 1-3, wherein the percentage is the mass percentage of each component in the modified asphalt.

7. A method for preparing modified asphalt according to claim 6, characterized in that, It includes the following steps: The asphalt modifier is heated and then mixed with the SBS modified asphalt to obtain the modified asphalt.

8. A modified asphalt mixture, characterized in that, It includes the following components: Minerals, modified bitumen and cenospheres as described in claim 6; The modified asphalt content is 3%-6%, and the cenosphere content is 4%-8%, with the percentages representing the mass percentage of each component relative to the mineral material.

9. A method for preparing the modified asphalt mixture according to claim 8, characterized in that, It includes the following steps: The mineral material, the modified asphalt, and the cenospheres are mixed evenly.

10. An application of the asphalt mixture according to claim 8 in a road paving structure.

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