Ultra-high viscosity modified asphalt direct injection additive and preparation method thereof

Abstract

This invention discloses an ultra-high viscosity modified asphalt direct-injection additive and its preparation method. The raw materials include recycled polyethylene plastic granules, high-elasticity crack-resistant particles, polyester, naphthenic rubber processing oil, carbon black, and magnesium hydroxide powder. Recycled polyethylene plastic granules are chosen because they have better mechanical toughness and anti-aging properties, significantly improving the dynamic viscosity of asphalt. The addition of high-elasticity crack-resistant particles greatly improves the adhesion between asphalt and aggregates, reducing the risk of particle scattering on the road surface, and has a significant warm-mix effect, improving the workability of the mixture and reducing the temperature requirements for production and construction. The addition of polyester improves workability during construction. The addition of naphthenic rubber processing oil improves the processing and workability of the material, while also enhancing its low-temperature performance. The addition of carbon black, which is produced from the thermal cracking of waste tires, is low-cost and environmentally friendly. The addition of magnesium hydroxide powder increases the additive's ignition point and suppresses the generation of flue gas during the mixture production process.

Description

Technical Field

[0001] This invention belongs to the field of road surface technology, specifically relating to a direct-injection additive for ultra-high viscosity modified asphalt and its preparation method. Background Technology

[0002] Drainage asphalt pavement can improve road safety and reduce traffic noise. In recent years, with the rapid development of sponge cities in my country, drainage asphalt pavement has been increasingly widely used. However, drainage asphalt pavement uses porous asphalt concrete, and the air and water in the pores accelerate the aging of the asphalt. At the same time, the dynamic water pressure generated by traffic loads in the pores causes pavement damage and easily leads to particle scattering. Therefore, higher requirements are placed on asphalt binders.

[0003] In China, high-viscosity asphalt or direct-injection high-viscosity additives are commonly used to pave drainage roads. The dynamic viscosity at 60℃ is used as an indicator to evaluate high-viscosity asphalt. Generally, the dynamic viscosity at 60℃ is required to be greater than 50,000 Pa·s, and some places have begun to require it to be greater than 400,000 Pa·s.

[0004] To achieve this target, domestic manufacturers currently employ a technique that heavily incorporates thermoplastic elastomers (most typically styrene-butadiene-styrene block copolymers, SBS) for both high-viscosity asphalt and high-viscosity additives. This approach is costly, and the effect of thermoplastic elastomers on dynamic viscosity is approximately linear; dynamic viscosity is high at 60°C and also relatively high at 180°C. This places higher temperature requirements on asphalt mixture production and construction, generally requiring a production temperature above 185°C. Even so, construction in low-temperature seasons presents challenges due to the low ambient temperature, leading to increased road surface construction difficulties, insufficient compaction, and a higher likelihood of particle scattering and loss. There have been instances of large-scale particle scattering on the road surface less than three months after construction was completed.

[0005] Therefore, there is an urgent need for an additive that can significantly improve the low-temperature dynamic viscosity of asphalt mixtures and can be applied directly to reduce the high-temperature dynamic viscosity, thus facilitating construction. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide a direct-injection additive for ultra-high viscosity modified asphalt and its preparation method. This ultra-high viscosity modified asphalt direct-injection additive significantly increases the low-temperature dynamic viscosity of asphalt mixtures and significantly reduces the high-temperature dynamic viscosity, making it easier to produce and apply, and convenient to use.

[0007] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0008] A direct-injection additive for ultra-high viscosity modified asphalt, the components of which and their mass percentages are as follows: 60-70% recycled polyethylene plastic granules, 10-19% high-elasticity crack-resistant particles, 10-35% polyester, 10-15% naphthenic rubber processing oil, 1-3% carbon black, and 2-10% magnesium hydroxide powder.

[0009] In a preferred embodiment of the present invention, the recycled polyethylene plastic pellets are primary recycled pellets. Their technical specifications are shown in Table 1 below:

[0010] Table 1

[0011] 1 Melt flow rate (190℃, 2.16 kg) g / 10min 0.5-2.5 GB / T3682 2 Density at 23℃ <![CDATA[g / cm 3 ]]> ＜1 GB / T1033 3 Melting point ℃ 120-150 GB / T19466 4 Tensile strength MPa ＞8 GB / T1040 5 Ash ％ ＜1 GB / T9345.1

[0012] The aforementioned recycled polyethylene plastic granules have better mechanical toughness and anti-aging properties, and can significantly improve the dynamic viscosity of asphalt.

[0013] In a preferred embodiment of the present invention, the raw materials of the high-elasticity crack-resistant particles and their weight ratios are as follows: 60-80 parts linear triblock copolymer, 30-50 parts white oil, 1-4 parts polyethylene wax, and 3-8 parts resin. Its technical specifications are shown in Table 2 below.

[0014] Table 2

[0015] 1 Appearance - Granular, uniform, and plump - 2 Single particle mass g ≤0.015 - 3 density <![CDATA[g / cm 3 ]]> 0.85～0.99 GT1033 4 Melt flow index (135℃, 2.16kg) g / 10min ≥3 GT / T3682 5 Ash ％ ≤1 T0614

[0016] The high-elasticity, crack-resistant particles possess outstanding bonding ability, significantly improving the adhesion between asphalt and aggregate, and reducing the risk of particle scattering on the road surface. Simultaneously, this material exhibits a significant warm-mix effect, enhancing the workability of the mixture and reducing the required production and construction temperatures.

[0017] In a preferred embodiment of the present invention, the polyester is preferably a low-melting-point polyester, which is a copolyester formed by the co-condensation of terephthalic acid, isophthalic acid, and ethylene glycol. The mass ratio of terephthalic acid to isophthalic acid is 100:100-60, the molecular weight is 5000-50000, and the melting point is 100-140℃. Upon melting, its viscosity rapidly and significantly decreases, effectively reducing the viscosity of asphalt under high-temperature conditions and improving workability. When its temperature drops below the melting point, it rapidly crystallizes to form high-strength fibers. These fibers, working together with PE, form a continuous fiber / PE network in the binder, greatly enhancing the strength of the binder below 100℃ and improving its resistance to high temperatures, fatigue, and cracking. Its technical specifications are shown in Table 3 below.

[0018] Table 3

[0019] 1 Melt flow rate (145℃, 2.16 kg) g / 10min >3 GB / T3682 2 Density (23℃) <![CDATA[g / cm 3 ]]> ＜1 GB / T1033 3 Melting point ℃ 110-140 GB / T19466 4 Viscosity (150℃) Pa·S <1.5 GB / T7193 5 Ash ％ ＜1 GB / T9345.1

[0020] As a preferred embodiment of the present invention, the naphthenic rubber processing oil is preferably N4006 rubber oil, and its technical specifications are shown in Table 4 below.

[0021] Table 4

[0022]

[0023] In a preferred embodiment of the present invention, the carbon black is pyrolysis powder carbon black from waste tires. Carbon black is added as a reinforcing agent and UV stabilizer during the preparation of tire rubber. Waste tires, after pyrolysis, will regenerate carbon black, essentially maintaining their original properties, but with significantly reduced costs. The technical specifications of the carbon black are shown in Table 5 below.

[0024] Table 5

[0025]

[0026] The magnesium hydroxide powder described in this invention is used to increase the ignition point of the additive and suppress the generation of flue gas during the production of the mixture. The technical indicators are shown in Table 6 below (the test methods refer to the provisions of the industry standard "HG / T 4531-2013").

[0027] Table 6

[0028] <![CDATA[Magnesium hydroxide [Mg(OH)2] w / % ≥]]><![CDATA[]]>< 91 Drying weight loss w / % ≤ 1 Weight loss on burning w≥ 28 Hydrochloric acid insoluble matter w / % ≤ 3 Calcium oxide (CaO) w / % ≤ 2 Chloride (as Cl) w / % ≤ - Iron (Fe) w / % ≤ 0.25 <![CDATA[Specific surface area (BET) / (m 2 / g)≤]]> - Particle size (D50) / μm ≤ 10

[0029] As a preferred embodiment of the present invention, the ultra-high viscosity modified asphalt direct-injection additive of the present invention can be directly added to the mixing pot of the asphalt concrete mixing plant without being added to the asphalt, and the addition ratio is 0.4 to 0.6% of the asphalt concrete.

[0030] A method for preparing the ultra-high viscosity modified asphalt direct-injection additive, comprising the following steps:

[0031] (1) Prepare the raw materials for the ultra-high viscosity modified asphalt direct-injection additive;

[0032] (2) Add polyethylene recycled plastic granules, high elastic crack-resistant particles, polyester, carbon black and magnesium hydroxide powder into the hopper in proportion, and then add naphthenic rubber processing oil. Preferably, the naphthenic rubber processing oil is heated to 40-60°C and then slowly poured into the hopper while stirring to obtain a mixture.

[0033] (3) The mixture is fed into a screw extruder for extrusion granulation to obtain additive granules.

[0034] The screw extruder can be a single-screw or twin-screw extruder. The material inlet temperature of the screw extruder is set at 170–180°C, with a maximum setting of 190–200°C in the middle of the screw, and the temperature gradually decreases thereafter, with the outlet temperature set at 140–150°C. During granulation, a strip cutter or a water ring cutter can be used to cut and granulate the material, ensuring that the mass of a single additive particle does not exceed 0.03g, which facilitates melt dispersion during addition to the asphalt mixture.

[0035] The beneficial effects of this invention are as follows: The formulation of the ultra-high viscosity modified asphalt direct-injection additive provided by this invention is reasonable. It selects recycled polyethylene plastic particles, which have better mechanical toughness and anti-aging properties, and can significantly improve the dynamic viscosity of asphalt. The addition of high-elasticity crack-resistant particles can greatly improve the bonding performance between asphalt and aggregate, reduce the risk of particle scattering on the road surface, and has a significant warm-mix effect, improving the workability of the mixture and reducing the temperature requirements for production and construction. The addition of polyester, when melted, rapidly and significantly reduces viscosity, effectively reducing the viscosity of asphalt under high-temperature conditions and improving workability. When its temperature drops below the melting point, it rapidly crystallizes to form high-strength fibers, exhibiting good resistance to high temperatures, fatigue, and cracking. The addition of naphthenic rubber processing oil improves the processing and workability of the material, while also enhancing its low-temperature performance. The addition of carbon black, produced from the thermal cracking of waste tires, is low-cost and environmentally friendly. The addition of magnesium hydroxide powder can increase the ignition point of the additive and suppress the generation of flue gas during the mixture production process. In summary, the ultra-high viscosity modified asphalt direct-injection additive of this invention can significantly increase the low-temperature dynamic viscosity of asphalt mixtures while significantly reducing the high-temperature dynamic viscosity, making it easier to produce and apply, and convenient to use. It is produced using recycled polyethylene granules, high-elasticity crack-resistant particles, polyester, naphthenic rubber processing oil, carbon black, and magnesium hydroxide powder, enabling the recycling of waste resources, reducing costs, and possessing broad market prospects.

[0036] The present invention will be further described below with reference to the embodiments. Detailed Implementation

[0037] Example 1: This example provides an ultra-high viscosity modified asphalt direct-injection additive and its preparation method. The components and their masses are as follows: Ultra-high viscosity modified additive 1 is prepared by producing recycled polyethylene particles: high elastic crack-resistant particles: polyester: naphthenic rubber oil: carbon black: magnesium hydroxide = 65:12:10:13:2:8. The technical indicators are shown in Table 7.

[0038] The ultra-high viscosity modifier 1 was added to SBS modified asphalt to modify it, and the technical indicators of the modified asphalt were measured as shown in Table 8.

[0039] The ultra-high viscosity modifier 1 was added to the modified asphalt PA-13 asphalt mixture by direct injection at a rate of 0.4% of the mixture mass. Relevant performance indicators are shown in Table 9.

[0040] Example 2: This example provides a direct-injection additive for ultra-high viscosity modified asphalt and its preparation method, which is basically the same as Example 1. The difference is that the ultra-high viscosity modified additive 1 is added to the modified asphalt PA-13 asphalt mixture by direct injection, and the amount added is 0.3% of the mass of the mixture. The relevant performance indicators are shown in Table 9.

[0041] Example 3: This example provides an ultra-high viscosity modified asphalt direct-injection additive and its preparation method. The components and their masses are as follows: Ultra-high viscosity modified additive 2 is prepared according to the ratio of recycled polyethylene particles: high elastic crack-resistant particles: polyester: naphthenic rubber oil: carbon black: magnesium hydroxide = 60:19:20:10:1:10. The technical indicators are shown in Table 7.

[0042] The specific technical indicators of ID-type SBS modified asphalt with 10% of the ultra-high viscosity modifier of this invention are shown in Table 8.

[0043] The ultra-high viscosity modifier was added to the modified asphalt PA-13 asphalt mixture via direct injection. The relevant performance indicators are shown in Table 9.

[0044] Example 4: This example provides an ultra-high viscosity modified asphalt direct-injection additive and its preparation method. The components and their masses are as follows: Ultra-high viscosity modified additive 3 is prepared according to the ratio of recycled polyethylene particles: high elastic crack-resistant particles: polyester: naphthenic rubber oil: carbon black: magnesium hydroxide = 70:10:35:15:3:2. Its technical indicators are shown in Table 7.

[0045] The specific technical indicators of ID-type SBS modified asphalt with 10% of the ultra-high viscosity modifier of this invention are shown in Table 8.

[0046] The ultra-high viscosity modifier was added to the modified asphalt PA-13 asphalt mixture via direct injection. The relevant performance indicators are shown in Table 9.

[0047] Comparative Example 1: SBS modified asphalt 1-D was selected, and its technical indicators are shown in Table 8. PA-13 asphalt mixture was prepared using SBS asphalt, and the relevant performance indicators are shown in Table 9.

[0048] Comparative Example 2: Conventional high-viscosity modified asphalt was selected, and its technical indicators are shown in Table 8. PA-13 asphalt mixture was prepared using high-viscosity modified asphalt, and the relevant performance indicators are shown in Table 9.

[0049] Table 7 shows the technical specifications of ultra-high viscosity additives.

[0050]

[0051] Table 8 shows the technical specifications of different asphalts.

[0052]

[0053] Table 9 shows the technical specifications of different PA-13 asphalt mixtures.

[0054]

[0055] As shown in Table 8, the dynamic viscosity of ID-type SBS modified asphalt significantly increased after adding 10% ultra-high viscosity modifier. The existing 60℃ dynamic viscosity test was no longer sufficient, indicating its ultra-high viscosity. Therefore, a 70℃ dynamic viscosity test was conducted to obtain the necessary data. This demonstrates that under road use conditions, the ultra-high viscosity modified asphalt mixture exhibits superior mechanical properties, excellent high-temperature performance, and improved road deformation resistance. Furthermore, the 180℃ Brookfield rotational viscosity, reflecting the mixing conditions of the mixture, shows that the ultra-high viscosity modified asphalt of this invention is significantly lower than that of conventional high-viscosity modified asphalt, proving that the ultra-high viscosity modified asphalt has superior workability compared to conventional high-viscosity modified asphalt.

[0056] As shown in Table 9, the high-temperature performance of ultra-high viscosity PA-13 asphalt mixture is more than twice that of conventional high-viscosity modified asphalt mixture and 3-5 times that of modified asphalt mixture.

[0057] The molded PA-13 Marshall specimens were aged using a pressure aging test to simulate the aging performance of asphalt mixtures under long-term use. A scattering test was then conducted on the aged specimens to test the bonding ability of the binder to the aggregate after aging. Table 9 shows that the asphalt modified with the ultra-high viscosity modifier exhibits good aging resistance and can effectively reduce the risk of aggregate spalling in drainage pavements.

[0058] This invention's ultra-high viscosity modified additive significantly increases the dynamic viscosity of asphalt at 60°C, improving pavement performance. Simultaneously, it reduces the rotational viscosity at 180°C compared to conventional high-viscosity modified asphalt, resulting in superior production, construction, and workability. While enhancing performance, the extensive use of recycled materials provides a significant cost advantage. Compared to conventional high-viscosity modified asphalt, the cost per ton of mixture is reduced by approximately 10%. Furthermore, due to the lower density of the mixture (approximately 20% less than conventional modified asphalt mixtures), it can save about 20% of pavement construction materials for the same mileage, resulting in a lower cost per square meter than roads paved with conventional modified asphalt mixtures. Moreover, it consumes waste materials, achieving efficient utilization of waste resources, demonstrating significant environmental benefits and outstanding market potential.

[0059] Based on the disclosure and teachings of the above specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention. As described in the above embodiments of the present invention, other additives and their preparation methods obtained using the same or similar methods and components are all within the protection scope of the present invention.

Claims

1. A direct addition super high viscosity modified asphalt additive characterized by, The components and their mass percentages of the raw materials are as follows: 60-70% recycled polyethylene plastic pellets High-elasticity, crack-resistant particles 10-19%, Polyester 10-35%, Naphthenic rubber processing oil 10-15%, Carbon black 1-3%, 2-10% magnesium hydroxide powder; The raw materials of the high-elasticity crack-resistant particles and their weight ratios are as follows: 60-80 parts of linear triblock copolymer, 30-50 parts of white oil, 1-4 parts of polyethylene wax, and 3-8 parts of resin. The polyester is a copolyester formed by the co-condensation of terephthalic acid, isophthalic acid and ethylene glycol.

2. The ultra-high viscosity modified asphalt direct addition additive according to claim 1, characterized in that, The polyethylene recycled plastic pellets are primary recycled pellets.

3. The ultra-high viscosity modified asphalt direct addition additive according to claim 1, characterized in that, The cycloalkyl rubber processing oil is N4006 rubber oil.

4. The ultra-high viscosity modified asphalt direct addition additive according to claim 1, characterized in that, The carbon black is carbon black powder from the pyrolysis of waste tires.

5. The direct addition super high viscosity modified asphalt additive according to any one of claims 1-4, characterized in that, It can be added directly to the mixing bowl of the asphalt concrete mixing plant, without adding it to the asphalt, and the addition ratio is 0.4 to 0.6% of the asphalt concrete.

6. A process for the preparation of the direct addition of the super high viscosity modified bitumen according to any one of claims 1 to 5, characterized by, It includes the following steps: (1) The raw material for preparing the ultra-high viscosity modified asphalt direct-injection additive as described in any one of claims 1 to 5; (2) Add polyethylene recycled plastic granules, high elastic crack-resistant particles, polyester, carbon black and magnesium hydroxide powder into the hopper in proportion, and then add naphthenic rubber processing oil to obtain a mixture; (3) The mixture is fed into a screw extruder for extrusion granulation to obtain additive granules.

7. The preparation method according to claim 6, characterized in that, The cycloalkyl rubber processing oil in step (2) is heated to 40-60°C and then slowly poured into the hopper while stirring.

8. The preparation method according to claim 6, characterized in that, In step (3), the material inlet temperature of the screw extruder is set to 170-180°C, the maximum temperature of the screw intermediate section is set to 190-200°C, and the outlet temperature is set to 140-150°C.

9. The preparation method according to claim 6, characterized in that, In step (3), granulation is performed using a strip cutter or a water ring cutter, and the mass of a single additive particle does not exceed 0.03g.

Images