Dry-type high-viscosity modified asphalt mixture

Abstract

The application discloses a dry-method high-viscosity modified asphalt mixture and belongs to the technical field; solves the technical problem that the existing high-viscosity high-elasticity modified asphalt has long storage time and unstable performance during high-temperature storage; and provides the dry-method high-viscosity modified asphalt mixture which comprises, by mass, 86.7-92.6 parts of aggregate, 3-8 parts of mineral powder, 0.4-0.8 parts of high-viscosity modifier and 4.0-4.5 parts of asphalt. The high-viscosity high-elasticity modifier can be placed at normal temperature and used at any time, and has stable performance; and the dry-method high-viscosity modified asphalt mixture prepared from the high-viscosity high-elasticity modifier also has stable performance.

Description

Technical Field

[0001] This invention relates to the field of modified asphalt technology, and more particularly to a dry-process high-viscosity modified asphalt mixture. Background Technology

[0002] With the rapid development of China's economy, the number of private cars owned by Chinese residents is increasing day by day, domestic traffic volume is growing rapidly, and the domestic highway industry is also developing rapidly. In the field of road engineering, the use function of road surfaces is being improved to provide safer, more comfortable and more environmentally friendly road surface characteristics.

[0003] Furthermore, with the continuous improvement of my country's expressway network, my country's expressways have entered a period of reconstruction, expansion, and maintenance, with nearly 10,000 kilometers of expressways entering their maintenance period each year. After several years of repeated loads, some expressways exhibit varying degrees of pavement damage, such as rutting, cracks, and coarse aggregate wear. To control these minor defects before structural damage occurs, expressway maintenance departments employ preventative maintenance solutions such as high-performance ultra-thin overlays to further extend the service life of the pavement and save maintenance costs.

[0004] Existing wet-process high-viscosity modified asphalt requires the addition of various types of modifying additives during production. Repeated or omitted additions occur during processing, leading to unstable performance of the high-viscosity modified asphalt. Furthermore, the performance of wet-process high-viscosity modified asphalt mixtures becomes unstable during the process of being transported to the construction site due to high-temperature storage and long transportation times. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide a dry-process high-viscosity modified asphalt mixture to solve the technical problems of long storage time and unstable performance of existing high-viscosity and high-elasticity modified asphalt during high-temperature storage.

[0006] The objective of this invention is mainly achieved through the following technical solutions:

[0007] This invention provides a dry-process high-viscosity modified asphalt mixture, the high-viscosity modified asphalt mixture comprising, by weight:

[0008] Aggregate: 86.7–92.6 parts, mineral powder: 3–8 parts, high viscosity modifier: 0.4–0.8 parts, and asphalt: 4.0–4.5 parts.

[0009] In one possible design, the dry-process high-viscosity modified asphalt mixture comprises, by mass:

[0010] Aggregate: 90 parts, mineral powder: 4.6 parts, high viscosity modifier: 0.8 parts, asphalt: 4.5 parts.

[0011] In one possible design, the dosage of the high-viscosity modifier is 12% to 15.5% of the base asphalt dosage, by mass ratio.

[0012] In one possible design, the aggregate includes 10-15mm crushed stone, 5-10mm crushed stone, 3-5mm crushed stone and 0.001-3mm crushed stone.

[0013] In one possible design, the mass ratio of 10-15mm gravel, 5-10mm gravel, 3-5mm gravel, and 0.001-3mm gravel is 15-19:34-38:14-18:25-29.

[0014] In one possible design, the mass ratio of 10-15mm gravel, 5-10mm gravel, 3-5mm gravel, and 0.001-3mm gravel is 17:36:16:27.

[0015] In one possible design, the raw materials for preparing the high-viscosity modifier include SBS, compatibilizer, reinforcing agent, thickener, plasticizer, crosslinking agent, and filler.

[0016] In one possible design, the SBS can be one or more of the following: linear SBS, star SBS, SIS, and SEBS.

[0017] In one possible design, the compatibilizer includes one or more of aromatic oil 11#, aromatic oil 2#, aromatic oil 4# and aromatic oil 10#.

[0018] In one possible design, the reinforcing agent includes one or more of silica, low-density polyethylene, and low-density polypropylene.

[0019] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0020] (1) The high viscosity and high elasticity modifier of the present invention can be stored at room temperature, is ready for use at any time, and has stable performance.

[0021] (2) During the transportation of dry-process high-viscosity modified asphalt, the high-viscosity modifier will continue to develop and improve the high-temperature rutting resistance of the road surface. Some of the high-viscosity modifier will also be embedded in the voids of the asphalt mixture to improve the low-temperature performance of the road surface.

[0022] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained through the embodiments described and the accompanying drawings, which are particularly pointed out. Attached Figure Description

[0023] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0024] Figure 1 This is a schematic diagram of the preparation process of the dry-process high-viscosity modified asphalt mixture of the present invention. Detailed Implementation

[0025] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0026] On the one hand, the present invention provides a dry-process high-viscosity modified asphalt mixture, which comprises the following components and contents by weight:

[0027] Aggregate: 86.7–92.6 parts, mineral powder: 3–8 parts, high viscosity modifier: 0.4–0.8 parts, and asphalt: 4.0–4.5 parts.

[0028] Furthermore, the aforementioned dry-process high-viscosity modified asphalt mixture includes the following components and their contents by weight:

[0029] Aggregate: 95.3 parts, mineral powder: 4 parts, high viscosity modifier: 0.5 parts, asphalt: 4.2 parts.

[0030] It should be noted that in the above-mentioned dry-process high-viscosity modified asphalt mixture, the dosage of the high-viscosity modifier is 12% to 15.5% of the matrix asphalt dosage by mass.

[0031] The purpose of controlling the dosage of high-viscosity modifier within the range of 12% to 15.5% of the base asphalt dosage is to ensure the best dispersion effect and superior performance of the high-viscosity modified asphalt mixture.

[0032] In the aforementioned dry-process high-viscosity modified asphalt mixture, the aggregate used is a mixture of coarse and fine crushed stone aggregates, including crushed stone of 10-15mm, 5-10mm, 3-5mm, and 0.001-3mm. Using these four particle sizes of crushed stone can meet the requirements of existing asphalt mixture gradation.

[0033] In order to achieve the required porosity range and optimize the mixing effect of aggregates, the mass ratio of 10-15mm crushed stone, 5-10mm crushed stone, 3-5mm crushed stone and 0.001-3mm crushed stone in this invention is (15-19):(34-38):(14-18):(25-29).

[0034] In the aforementioned dry-process high-viscosity modified asphalt mixture, the mass ratio of 10-15mm crushed stone, 5-10mm crushed stone, 3-5mm crushed stone, and 0.001-3mm crushed stone is 17:36:16:27.

[0035] In the aforementioned dry-process high-viscosity modified asphalt mixture, the preparation process of the high-viscosity modifier includes: mixing SBS, compatibilizer, reinforcing agent, tackifier, plasticizer, crosslinking agent and filler by high-speed stirring at a stirring rate of 300RPM-500RPM and a mixing time of 10min-30min; extruding the mixture by twin-screw extrusion at an extrusion temperature of 140℃-170℃; and then shearing and crushing the extruded high-viscosity modifier by a crusher.

[0036] It should be emphasized that the high viscosity modifier of the present invention is mainly composed of polymers, with the addition of modifying additives to form a high viscosity modifier. Due to the high temperature in the mixing pot, the high viscosity modifier melts into the asphalt through stirring and collision with the aggregate.

[0037] In the preparation process of the above high-viscosity modifier, SBS: compatibilizer: reinforcing agent: thickener: plasticizer: crosslinking agent: filler = (56-60):(6-10):(10-14):(7-9):(7-9):(1-3):(4-8); Controlling the components of the high-viscosity modifier within the above range has the following advantages: First, it can achieve the high viscosity effect of the high-viscosity modifier; second, it can ensure that the high-viscosity modifier is better dispersed in the asphalt mixture; third, it makes the high-viscosity modified asphalt mixture easier to form and granulate, and there is no odor during the production of the modifier.

[0038] It should be noted that among the above-mentioned high-viscosity modifiers, SBS is a polymer elastomer that can improve the low-temperature crack resistance and low-temperature ductility of asphalt mixtures.

[0039] Among the above-mentioned high-viscosity modifiers, the thickener can improve the adhesion between asphalt and aggregates. It is in a molten state at high temperatures, is easy to solidify, and is easy to granulate.

[0040] Among the aforementioned high-viscosity modifiers, the plasticizer is a liquid modifying agent that can accelerate the melting of the high-viscosity modifier during the mixing process of asphalt mixtures and protect the properties of other materials from degradation during the extrusion molding process.

[0041] Among the aforementioned high-viscosity modifiers, the crosslinking agent can improve the storage stability of the high-viscosity modifier during the high-temperature process of asphalt mixture.

[0042] Among the aforementioned high-viscosity modifiers, the filler can slightly improve the strength of asphalt mixtures, and as a filler, it can reduce production costs.

[0043] In the process of preparing the above-mentioned high viscosity modifier, the stirring rate is controlled within the range of 300 RPM-500 RPM and the mixing time is controlled within the range of 10 min-30 min, which can ensure that the high viscosity modifier is fully dispersed.

[0044] In addition, during the preparation of the above-mentioned high viscosity modifier, the extrusion temperature of the twin-screw extrusion is controlled within the range of 140℃-170℃. Controlling the temperature within this range not only achieves the extrusion molding effect, but also results in poor extrusion molding effect. Excessive temperature leads to a significant degradation of the performance of the high viscosity modifier.

[0045] In the process of preparing the high-viscosity modifier, the twin-screw extruder can extrude the mixed modifier into strips, which is an essential process for subsequent granulation.

[0046] Among the aforementioned high-viscosity modifiers, the SBS used is one or more of linear SBS, star-shaped SBS, SIS, and SEBS. SBS is used to improve the low-temperature aging crack resistance and low-temperature ductility of high-viscosity modified asphalt; SBS, as the main raw material of high-viscosity modifiers, is physically dispersed with other modifying additives into a mixture.

[0047] It should be noted that SBS is a thermoplastic elastomer, short for styrene-butadiene-styrene copolymer. SBS comes in linear and star-shaped forms; the difference is that linear SBS is not cross-linked, while star-shaped SBS is cross-linked with silicon tetrachloride. SEBS is a saturated SBS, and SIS is a styrene-isoprene-styrene copolymer, also a thermoplastic elastomer.

[0048] The compatibilizer in the aforementioned high-viscosity modifier includes one or more of aromatic oil 11#, aromatic oil 2#, aromatic oil 4#, and aromatic oil 10#. This compatibilizer can accelerate the melting of SBS in asphalt and, due to the high extrusion temperature during the production process of the high-viscosity modifier, can protect the properties of other modifying additives.

[0049] The reinforcing agent in the aforementioned high-viscosity modifier includes one or more of silica, low-density polyethylene, and low-density polypropylene. This reinforcing agent can improve the strength of the high-viscosity modifier, which, when melted in asphalt, enhances the high-temperature performance of asphalt and asphalt mixtures.

[0050] The tackifiers in the above-mentioned high viscosity modifiers include one or more of petroleum resin C9, petroleum resin C5, thiocyanate resin, and coumarone resin; the tackifiers, as the main modifying additives of the high viscosity modifiers, are used to improve the viscosity of the high viscosity modifiers and are easy to granulate in the high viscosity modifier production process.

[0051] The plasticizers in the aforementioned high-viscosity modifiers include DOP and / or DBP. The function of these plasticizers is to accelerate the melting of the high-viscosity modifier in asphalt; wherein, DOP is dimethyl phthalate; and DBP is dibutyl phthalate.

[0052] The crosslinking agent in the above-mentioned high viscosity modifier includes one or more of sulfur, nano zinc oxide, and stearic acid; the function of the crosslinking agent is to improve the high-temperature storage stability of high viscosity modified asphalt mixture and enhance the crosslinking effect of SBS in asphalt.

[0053] The fillers in the aforementioned high-viscosity modifier include nano-calcium carbonate and / or organic active clay. The function of these fillers is to improve the strength of the high-viscosity modified asphalt mixture and reduce the material cost of the high-viscosity modifier.

[0054] On the other hand, the present invention also provides a method for preparing a dry-process high-viscosity modified asphalt mixture, used to prepare the above-mentioned dry-process high-viscosity modified asphalt mixture, such as... Figure 1 As shown, the preparation method includes the following steps:

[0055] Step 1: Weigh the raw materials for dry-process high-viscosity modified asphalt mixture according to a certain mass ratio;

[0056] In step 1 above, the raw materials for dry-process high-viscosity modified asphalt mixtures include aggregates, mineral powder, high-viscosity modifiers, and base asphalt.

[0057] In step 1 above, the components of the raw material and their mass content are as follows:

[0058] Aggregate: 86.7-92.6 parts, mineral powder: 3-8 parts, high viscosity modifier: 0.4-0.8 parts, base asphalt: 4.0-4.5 parts.

[0059] Step 2: Place the aggregate on the heating device and heat it to form hot aggregate. Place the hot aggregate in the mixing pot, and then add the high viscosity modifier into the mixing pot for dry mixing, so that the hot aggregate and the high viscosity modifier are fully stirred and dispersed.

[0060] In step 2 above, the heating device is a blower-type constant temperature drying oven to ensure that the aggregate is heated evenly.

[0061] In step 2 above, the aggregate is heated in a blower-type constant temperature drying oven at a temperature of 175℃~185℃ for 3~5 hours; the mixing temperature of the hot aggregate and the high viscosity modifier is 170℃~175℃ and the mixing time is 30s~60s, so that the high viscosity modifier can be evenly dispersed in the hot aggregate, avoiding segregation or insufficient discharge temperature and excessive temperature in the later stage of the high viscosity modified asphalt mixture.

[0062] Step 3: Place the base asphalt in a heating device (e.g., a blower-type constant temperature drying oven) and heat it to 145℃~160℃ for 1~3 hours to enhance the fluidity of the base asphalt. Then, add the heated base asphalt to the mixing pot from Step 2 in a certain proportion and stir and mix thoroughly at a mixing temperature of 170℃~175℃ for 120s~180s. Finally, add the mineral powder and continue mixing for a period of time to form a dry-process high-viscosity modified asphalt mixture.

[0063] In step 3 above, the mixing temperature during continued mixing is 170℃~175℃, and the mixing time is 120s~180s, so that the base asphalt, mineral powder, high viscosity modifier and aggregate can be evenly dispersed in the mixing pot.

[0064] Step 4: Let the mixed high-viscosity modified asphalt mixture stand in the mixing pot for a period of time, then continue mixing for a period of time, and finally discharge the material.

[0065] In step 4 above, to ensure the high-viscosity modifier fully develops in the high-viscosity modified asphalt mixture, the settling temperature in the mixing pot is 170℃~175℃, the settling time is 20~40min, and the mixing temperature after settling is 170℃~175℃; the mixing time is 30s~90s. By strictly controlling the settling temperature and time, better development of the high-viscosity modifier in the modified asphalt mixture is ensured. Continued mixing after settling is because slight clumping may occur during settling; the effect of mixing is to prevent clumping of the high-viscosity modified asphalt mixture.

[0066] It should be emphasized that the present invention first mixes aggregate with high-viscosity modifier, then adds base asphalt, and finally adds mineral powder. The purpose of this specific order of addition is: first, the hot aggregate and high-viscosity modifier are stirred to form a mixture, and the hot aggregate can preheat the high-viscosity modifier; then the hot base asphalt is added to the mixture and stirring is continued, and the hot base asphalt and high-viscosity modifier will melt; then the mineral powder is added and stirring is continued, and finally a high-viscosity modified asphalt mixture can be formed.

[0067] Existing wet-process high-viscosity, high-elasticity modified asphalt requires complex mixing and high-speed shearing. Furthermore, existing wet-process high-viscosity, high-elasticity modified asphalt requires high-temperature storage, which leads to performance changes over long periods. The high-viscosity, high-elasticity modifier of this invention can be stored at room temperature, is readily available, and exhibits stable performance. Compared to existing dry-process preparation methods, the mixing and discharge temperatures of this invention are both reduced.

[0068] It is important to emphasize that the thermal aggregate of this invention has a high temperature (175℃~185℃). Under the combined effects of high temperature and collision with the aggregate, the high-viscosity modifier can be dispersed. During the mixing process with the base asphalt, the high-viscosity modifier can melt well into the base asphalt and adhere to the aggregate, thereby forming a stable high-viscosity modified asphalt mixture. As the high-viscosity modified asphalt mixture develops under high-temperature conditions, the high-viscosity modifier can be better dispersed in the base asphalt mixture, thereby forming a stable network structure and ultimately improving the road performance of the high-viscosity modified asphalt mixture.

[0069] This invention employs a dry-process method for preparing high-viscosity modified asphalt mixtures, avoiding the degradation of thermal stability caused by prolonged storage of existing wet-process high-viscosity modified asphalt. Furthermore, the dry-process method for preparing high-viscosity modified asphalt mixtures uses a low mixing temperature, effectively reducing construction energy consumption and saving construction costs.

[0070] Existing dry-process modified asphalt mixtures cannot achieve excellent performance indicators such as high viscosity and high elasticity.

[0071] Dry-process high-viscosity modified asphalt mixtures have a lower mixing temperature than wet-process high-viscosity modified asphalt mixtures, which reduces energy consumption and saves construction costs. During the process of transporting wet-process high-viscosity modified asphalt mixtures to the construction site, the performance of the high-viscosity modified asphalt mixture deteriorates due to high-temperature storage and transportation. However, during transportation, the high-viscosity modifiers in dry-process high-viscosity modified asphalt continue to develop, improving the pavement's high-temperature rutting resistance. Some of the high-viscosity modifiers also embed themselves in the voids of the asphalt mixture, improving the pavement's low-temperature performance.

[0072] It is important to emphasize that this invention involves one dry mixing of the aggregates and two wet mixing processes for the high-viscosity modified asphalt mixture. The purpose of the first dry mixing of the hot aggregates and the high-viscosity modifier is to ensure the high-viscosity modifier is fully dispersed within the aggregates under the combined effects of high temperature and physical collision. Furthermore, the first wet mixing in step 3 accelerates the dispersion of the base asphalt, mineral powder, aggregates, and high-viscosity modifier, forming a dry-process high-viscosity modified asphalt mixture. Step 4 involves a static high-temperature development followed by a second dry mixing. The high-temperature development of the dry-process high-viscosity modified asphalt mixture improves its performance, while the second dry mixing further enhances its dispersion.

[0073] Compared with existing technologies, firstly, the high-viscosity modifier of the present invention has stable performance and is a molded asphalt modifier; secondly, in the dry mixing process, the high-viscosity modifier of the present invention can be ordered in one go and stored for a long time without performance degradation. The present invention solves the problem of performance degradation of high-viscosity modified asphalt during transportation in the wet mixing process.

[0074] This invention allows for the use of a high-viscosity modifier in a dry-mixing process because: the high-viscosity modifier melts with the base asphalt, and the powder, SBS, and compatibilizer in the high-viscosity modifier form tiny units embedded in the voids of the high-viscosity modified asphalt mixture, binding the aggregates and improving the low-temperature crack resistance and water loss resistance of the high-viscosity modified asphalt. The reinforcing agent in the high-viscosity modifier, stirred at high temperatures during dry mixing, is evenly distributed in the asphalt, improving the high-temperature performance of the high-viscosity modified asphalt mixture. The cross-linking stabilizer in the high-viscosity modifier enhances the cross-linking effect of the asphalt mixture, improving the low-temperature ductility of the asphalt, thereby improving the low-temperature crack resistance of the high-viscosity modified asphalt mixture.

[0075] Regarding production costs, this invention employs a dry-process high-viscosity modified asphalt mixture preparation method, which reduces the mixing temperature by 5-10℃ compared to the wet-process method (wet-process high-viscosity modified asphalt mixture mixing temperature: 175℃-180℃; dry-process high-viscosity modified asphalt mixture mixing temperature: 165℃-170℃). During construction, both the paving temperature and mixing temperature decrease by 5-10℃ (wet-process high-viscosity modified asphalt mixture paving temperature: 170℃-175℃; dry-process high-viscosity modified asphalt mixture paving temperature: 165℃-170℃), significantly reducing construction energy consumption.

[0076] Regarding raw material costs, the market price of high-viscosity modified asphalt used in the wet-process high-viscosity modified asphalt mixture is 8000 yuan / ton. Based on the AC-13 gradation and an asphalt-aggregate ratio of 4.9% used in the high-viscosity modified asphalt mixture, the calculated cost of asphalt for one ton of wet-process high-viscosity modified asphalt mixture is 375 yuan. Using the dry-process high-viscosity modified asphalt mixture preparation method, the market price of 70# base asphalt is 3580 yuan / ton. The market price of the high-viscosity modifier in this invention is 20000 yuan / ton. Using the AC-13 gradation and an asphalt-aggregate ratio of 4.4%, the high-viscosity modifier accounts for 12% of the 70# base asphalt. The calculated cost of base asphalt and high-viscosity modifier is 280 yuan / ton, reducing material costs by 20%-25%.

[0077] Example 1

[0078] Step 1: Weigh the raw materials for dry-process high-viscosity modified asphalt mixture according to the mass ratio;

[0079] Based on mass ratio, the components and their contents of the raw materials are as follows: aggregate: 92 parts, mineral powder: 3.5 parts, high viscosity modifier: 0.5 parts, and asphalt: 4.0 parts.

[0080] The aggregate composition and its mass ratio are as follows: the mass ratio of 10-15mm crushed stone, 5-10mm crushed stone, 3-5mm crushed stone and 0.001-3mm crushed stone is 17:36:16:27.

[0081] Step 2: Place the aggregate in a heating device and heat it to 180°C for 3 hours to form hot aggregate. Place the hot aggregate in a mixing pot and add the high viscosity modifier to the mixing pot. Dry mix for 45 seconds at a mixing temperature of 170°C to ensure that the hot aggregate and the high viscosity modifier are fully stirred and dispersed.

[0082] Step 3: Place the base asphalt in the heating device and heat it to 150℃. Add it to the mixing pot according to the proportion and stir and mix it thoroughly. Then add the mineral powder and continue to mix for a period of time. The mixing temperature is 170℃ and the mixing time is 150s to form a dry high-viscosity modified asphalt mixture.

[0083] Step 4: Let the mixed high-viscosity modified asphalt mixture stand in the mixing pot at a temperature of 170℃ for 30 minutes. After standing, continue mixing for 60 seconds and then discharge the material.

[0084] Example 2

[0085] Step 1: Weigh the raw materials for dry-process high-viscosity modified asphalt mixture according to the mass ratio;

[0086] According to the mass ratio, the components of the raw material include: aggregate: 91 parts, mineral powder: 4 parts, high viscosity modifier: 0.7 parts, and asphalt: 4.4 parts.

[0087] The aggregate consists of components in a fractional mass ratio: 10-15mm crushed stone, 5-10mm crushed stone, 3-5mm crushed stone and 0.001-3mm crushed stone in a mass ratio of 18:37:17:28.

[0088] Step 2: Place the aggregate in a heating device and heat it to 175°C for 4 hours to form hot aggregate. Place the hot aggregate in a mixing pot and add the high viscosity modifier to the mixing pot. Dry mix for 50 seconds at a mixing temperature of 172°C to ensure that the hot aggregate and the high viscosity modifier are fully stirred and dispersed.

[0089] Step 3: Place the base asphalt in the heating device and heat it to 155℃. Add it to the mixing pot according to the proportion and stir and mix it thoroughly. Then add the mineral powder and continue to mix for a period of time. The mixing temperature is 172℃ and the mixing time is 160s to form a dry high-viscosity modified asphalt mixture.

[0090] Step 4: Let the mixed high-viscosity modified asphalt mixture stand in the mixing pot. The standing temperature in the mixing pot is 173℃, and the standing time is 35 minutes. Then continue mixing for 70 seconds and then discharge the material.

[0091] Example 3

[0092] Step 1: Weigh the raw materials for dry-process high-viscosity modified asphalt mixture according to the mass ratio;

[0093] Based on mass ratio, its components include: aggregate: 90 parts, mineral powder: 4.6 parts, high viscosity modifier: 0.8 parts, and asphalt: 4.5 parts.

[0094] The aggregate consists of components with a fractional mass ratio: 10-15mm crushed stone, 5-10mm crushed stone, 3-5mm crushed stone and 0.001-3mm crushed stone in a mass ratio of 19:38:17:28.

[0095] Step 2: Place the aggregate in a heating device and heat it to 185°C to form hot aggregate. Place the hot aggregate in a mixing pot and add the high viscosity modifier to the mixing pot. Dry mix for 55 seconds at a mixing temperature of 175°C to ensure that the hot aggregate and the high viscosity modifier are fully stirred and dispersed.

[0096] Step 3: Place the base asphalt in the heating device and heat it at 160℃ for 3 hours. Add it to the mixing pot according to the proportion and stir and mix it thoroughly. Then add the mineral powder and continue to mix for a period of time. The mixing temperature is 175℃ and the mixing time is 170 seconds to form a dry high-viscosity modified asphalt mixture.

[0097] Step 4: Let the mixed high-viscosity modified asphalt mixture stand in the mixing pot. The standing temperature in the mixing pot is 175℃, and the standing time is 40 minutes. After standing, continue mixing at the same temperature of 175℃ for 90 seconds, and then discharge the material.

[0098] Example 4

[0099] This embodiment is used to determine the optimal dosage of the high-viscosity modifier. The high-viscosity modifier is mixed with base asphalt, and then sheared and developed to prepare the high-viscosity modified asphalt. The operation steps are as follows:

[0100] Step 1: Weigh the high-viscosity modified asphalt raw materials according to the following mass ratio: 87.5 parts of heavy-grade 70# A-grade asphalt and 12.5 parts of high-viscosity modifier;

[0101] The mass fraction of the high-viscosity modified asphalt raw material is: 400g of heavy-grade 70# A-grade asphalt and 50g of high-viscosity modifier;

[0102] Step 2: Heat the heavy cross-linked 70# Grade A asphalt in the reactor to 150°C, add the high viscosity modifier and stir and mix for 30 minutes;

[0103] Step 3: After the mixture with high viscosity modifier is blended, it is put into a colloid mill for high-speed shear grinding. The shear rate is 1800 rpm, the shearing time is 7 min, and the shearing temperature is 170℃.

[0104] Step 4: Place the sample in a 170℃ heating device and develop for 30 minutes to complete the sample preparation.

[0105] In this embodiment, a high-viscosity modifier was mixed with 70# Grade A asphalt to verify its compatibility and determine the optimal dosage of the high-viscosity modifier. The experimental results are shown in Table 1.

[0106] Table 1 Performance Indicators of High-Viscosity Modified Asphalt

[0107]

[0108] The high-viscosity modified asphalt prepared above is used to prepare wet-process high-viscosity modified asphalt mixtures. The operation steps are as follows:

[0109] Step 1: According to the mass ratio, the components include: aggregate: 91 parts, mineral powder: 4 parts, high viscosity modified asphalt: 5 parts.

[0110] The aggregate composition consists of crushed stone of 10-15mm, 5-10mm, 3-5mm and 0.001-3mm in mass ratio of 17:36:16:27.

[0111] Step 2: Place the aggregate in a heating device and heat it to 175℃-185℃ to form hot aggregate. Place the hot aggregate in a mixing pot and add the base asphalt placed in the heating device according to the proportion to the mixing pot for thorough mixing; mixing time 60s.

[0112] Step 3: Add mineral powder and continue mixing for a period of time. The mixing temperature is 170℃ and the mixing time is 150s to form a wet high-viscosity modified asphalt mixture.

[0113] Table 2 shows the performance of the high-viscosity modified asphalt mixture specimens prepared in the examples.

[0114]

[0115] In summary, based on the data in Table 1, it can be seen that when the high-viscosity modifier dosage (external admixture) is 12%-15.5%, the high-viscosity modifier exhibits good compatibility with heavy-duty 70# Grade A asphalt. Especially when the high-viscosity modifier dosage (external admixture) is 15.5%, the compatibility with heavy-duty 70# Grade A asphalt is excellent, with a softening point exceeding 85℃ and a ductility of 38.1 cm at 5℃, indicating that the high-viscosity modified asphalt possesses high high and low temperature performance. It also exhibits resistance to rutting at high temperatures and resistance to cracking at low temperatures.

[0116] In summary, based on the data in Table 2, it can be seen that with the increase of high-viscosity modifier dosage, the dynamic stability and water loss resistance of high-viscosity modified asphalt mixtures both increase to a certain extent. The increase of high-viscosity modifier dosage initially increases the low-temperature crack resistance of high-viscosity modified asphalt mixtures; however, once the dosage reaches a certain level, the low-temperature crack resistance decreases. Furthermore, the high-viscosity modifier production formula facilitates the granulation process.

[0117] As shown in Table 2, a dry-process high-viscosity modified asphalt mixture preparation method utilizes a self-developed high-viscosity modifier added to the base asphalt. The high-viscosity modifier can be delivered in a single shipment, can be stored long-term, and will not suffer performance loss. Compared with the wet-process high-viscosity modified asphalt mixture preparation method in the examples, both methods achieve the performance of the wet-process high-viscosity modified asphalt mixture.

[0118] Dry-process high-viscosity modified asphalt mixtures have a lower mixing temperature than wet-process high-viscosity modified asphalt mixtures, which reduces energy consumption and saves construction costs. During the process of transporting wet-process high-viscosity modified asphalt mixtures to the construction site, the performance of the high-viscosity modified asphalt mixture deteriorates due to high-temperature storage and transportation. However, during transportation, the high-viscosity modifiers in dry-process high-viscosity modified asphalt continue to develop, improving the pavement's high-temperature rutting resistance. Some of the high-viscosity modifiers also embed themselves in the voids of the asphalt mixture, improving the pavement's low-temperature performance.

[0119] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A dry-process high-viscosity modified asphalt mixture, characterized in that, The raw materials of the high-viscosity modified asphalt mixture are, by mass: Aggregate: 86.7~92.6 parts, mineral powder: 3~8 parts, high viscosity modifier: 0.4~0.8 parts, and base asphalt: 4.0~4.5 parts; The aggregates include 10-15mm crushed stone, 5-10mm crushed stone, 3-5mm crushed stone and 0.001-3mm crushed stone; The mass ratio of the 10-15mm gravel, 5-10mm gravel, 3-5mm gravel and 0.001-3mm gravel is 15-19:34-38:14-18:25-29; The raw materials for preparing the high-viscosity modifier include SBS, compatibilizer, reinforcing agent, thickener, plasticizer, crosslinking agent and filler; The preparation process of the high-viscosity modifier includes: mixing SBS, compatibilizer, reinforcing agent, thickener, plasticizer, crosslinking agent and filler by high-speed stirring at a stirring rate of 300RPM-500RPM and a mixing time of 10min-30min; extruding the mixture by twin-screw extrusion at an extrusion temperature of 140℃-170℃; and shearing and crushing the extruded high-viscosity modifier by a crusher. In the preparation process of the high viscosity modifier, SBS : compatibilizer : reinforcing agent : thickener : plasticizer : crosslinking agent : filler = (56-60) : (6-10) : (10-14) : (7-9) : (7-9) : (1-3) : (4-8); According to the mass ratio, the dosage of the high-viscosity modifier is 12% to 15.5% of the base asphalt dosage; The preparation method of the dry-process high-viscosity modified asphalt mixture includes the following steps: Step 1: Weigh the raw materials for dry-process high-viscosity modified asphalt mixture according to the mass ratio; Step 2: Place the aggregate on the heating device and heat it to form hot aggregate. Place the hot aggregate in the mixing pot, and then add the high viscosity modifier into the mixing pot for dry mixing, so that the hot aggregate and the high viscosity modifier are fully stirred and dispersed. Step 3: Place the base asphalt in the heating device and heat it to 145℃~160℃ for 1~3 hours. Then, add the heated base asphalt to the mixing pot in Step 2 according to a certain ratio and stir and mix it thoroughly. Finally, add the mineral powder and continue to mix for a period of time to form a dry high-viscosity modified asphalt mixture. Step 4: Let the mixed high-viscosity modified asphalt mixture stand in the mixing pot for a period of time, then continue mixing for a period of time, and finally discharge the material. The high-viscosity modified asphalt mixture is first left to stand in the mixing pot for a period of time. The standing temperature in the mixing pot is 170℃~175℃ and the standing time is 20~40 minutes. After standing, the mixing temperature is 170℃~175℃ and the mixing time is 30s~90s. After the mixing is completed, the material is discharged.

2. The dry-process high-viscosity modified asphalt mixture according to claim 1, characterized in that, The raw materials for the dry-process high-viscosity modified asphalt mixture are, by weight: Aggregate: 90 parts, mineral powder: 4.6 parts, high viscosity modifier: 0.8 parts, asphalt: 4.5 parts.

3. The dry-process high-viscosity modified asphalt mixture according to claim 1, characterized in that, According to the mass ratio, the dosage of the high viscosity modifier is 12.5% ​​to 15.5% of the matrix asphalt dosage.

4. The dry-process high-viscosity modified asphalt mixture according to claim 3, characterized in that, The mass ratio of the 10-15mm crushed stone, 5-10mm crushed stone, 3-5mm crushed stone, and 0.001-3mm crushed stone is 17:36:16:

27.

5. The dry-process high-viscosity modified asphalt mixture according to claim 4, characterized in that, The SBS is one or more of linear SBS and star SBS.

6. The dry-process high-viscosity modified asphalt mixture according to claim 5, characterized in that, The compatibilizer includes one or more of aromatic oil 11#, aromatic oil 2#, aromatic oil 4# and aromatic oil 10#.

7. The dry-process high-viscosity modified asphalt mixture according to claim 6, characterized in that, The reinforcing agent includes one or more of silica, low-density polyethylene, and low-density polypropylene.

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