A high-performance composite hydrated iron oxide-activated rubber modified asphalt and its preparation method

Abstract

The present invention belongs to the technical field of modified asphalt materials, and specifically discloses a high-performance composite hydrated iron oxide activated rubber modified asphalt. The high-performance composite hydrated iron oxide activated rubber modified asphalt comprises the following raw materials: hydrated iron oxide, waste vegetable oil, rubber powder, EVA, and asphalt. First, petroleum asphalt and EVA are mixed in mixing tank A and subjected to high-speed shearing. Subsequently, waste vegetable oil and rubber powder are placed in mixing tank B for pre-development of the rubber powder. Then, the mixture in mixing tank B and the mixture in mixing tank A are subjected to primary grinding and heat-preserving stirring. Finally, hydrated iron oxide is added for secondary grinding and heat-preserving stirring to form the finished product of the high-performance composite hydrated iron oxide activated rubber modified asphalt. The present invention solves the problems of high viscosity and poor compatibility of the existing rubber modified asphalt, effectively improves the rheological properties of the rubber modified asphalt at high and low temperatures, and has excellent stability, and can be used for the paving of roads of all grades.

Description

Technical Field

[0001] The invention belongs to the technical field of modified asphalt materials, and particularly relates to a high-performance composite hydrated iron oxide activated rubber modified asphalt and a preparation method thereof. Background Art

[0002] Rubber-modified asphalt is a road construction material made by mixing rubber powder from waste tires (referred to as rubber powder) with asphalt. Its main purpose is to improve the performance of asphalt while realizing the resource utilization of waste tires. Currently, the application of rubber-modified asphalt is gradually increasing worldwide, especially in terms of environmental protection and resource recycling. Rubber-modified asphalt has been widely used in many countries and regions such as the United States, Europe and China, mainly in areas such as highways, urban roads and airport runways. With the deepening of research, the preparation technology of rubber-modified asphalt has been continuously improved, including the mixing process of rubber powder and asphalt, rubber powder activation technology, etc., which significantly improves its performance. At the same time, many countries and regions have introduced relevant policies and regulations to encourage the use of rubber-modified asphalt to promote the recycling of waste tires and reduce environmental pollution.

[0003] Despite its significant performance and environmental advantages, rubber-modified asphalt still faces some problems and drawbacks in its practical application. First, the varying sources and quality of rubber powder can lead to unstable performance of rubber-modified asphalt, particularly under low and high temperature conditions. Second, the construction process of rubber-modified asphalt is complex, requiring specialized equipment and techniques, which increases both the difficulty and cost of construction. Furthermore, rubber-modified asphalt can age over long periods of use, impacting its service life and the durability of roads. Despite utilizing waste tires, its production and construction processes can still generate certain environmental pollution issues.

[0004] To overcome the shortcomings of traditional rubber-modified asphalt, researchers have proposed physical or chemical treatment of the rubber powder. This technique significantly improves its compatibility and activity with asphalt, resulting in a modified asphalt with superior performance. The activated rubber powder bonds more tightly with the asphalt, significantly enhancing the performance of the modified asphalt. Furthermore, by more fully utilizing waste tires, this technology reduces waste emissions and lowers pollutant emissions during the production process. Rubber powder activation technology can effectively slow the aging process of modified asphalt, extending the service life of roads and improving their overall performance.

[0005] However, the current rubber-modified asphalt still has problems such as complex activation processes and high activation costs. To solve these problems, it is particularly important to develop a high-performance composite hydrated iron oxide-activated rubber-modified asphalt with a simple activation process and stable performance. This can not only further improve the performance and application effect of the modified asphalt, but also promote its application on a larger scale, driving the sustainable development of road construction and the resource utilization of waste tires. Summary of the Invention

[0006] The present invention aims to provide a high-performance composite hydrated iron oxide-activated rubber-modified asphalt and its preparation method to solve the defects existing in the current rubber-modified asphalt in terms of activation and performance.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A high-performance composite hydrated iron oxide-activated rubber-modified asphalt, and the raw materials for preparing the high-performance composite hydrated iron oxide-activated rubber-modified asphalt include: hydrated iron oxide, waste vegetable oil, rubber powder, EVA, and asphalt;

[0009] Furthermore, the mass ratio of the hydrated iron oxide, waste vegetable oil, rubber powder, EVA, and asphalt is: (1-5):(15-20):(15-20):(1-5):100.

[0010] The present invention also provides a preparation method for the above high-performance composite hydrated iron oxide-activated rubber-modified asphalt, and the specific steps are as follows:

[0011] Step 1, Material mixing

[0012] Put the asphalt into mixing tank A according to the measurement, heat and melt the asphalt (preferably heat to 150-180 °C), then put EVA according to the measurement, and keep warm and stir until evenly mixed (preferably stir at a stirring rate of 1000 rpm for 30 min) to form a primary mixed material;

[0013] Step 2, High-speed shearing

[0014] Pump the primary mixed material into a high-speed shearing machine for sufficient grinding and shearing to obtain mixture A;

[0015] Step 3, Pre-swelling of rubber powder

[0016] Put the waste vegetable oil and rubber powder into mixing tank B, and heat to 150-180 °C, and stir for pre-swelling and development of the rubber powder with heat preservation to obtain mixture B;

[0017] Step 4, Primary grinding

[0018] Add mixture B to mixture A, and keep stirring at a temperature of 170 - 190°C for 20 - 45 minutes with a stirring rate of 500 - 800 rpm to form a secondary mixed material; pump the secondary mixed material into a high-speed shear emulsifier for primary grinding with a grinding gap of 0.7 - 2 mm and a rotational speed of 5000 - 12000 rpm during grinding; then introduce the ground secondary mixed material into mixing tank C and keep stirring at a temperature of 170 - 190°C for 30 - 45 minutes with a stirring rate of 1000 - 1500 rpm;

[0019] Step Five, secondary grinding

[0020] Then add hydrated iron oxide to the mixed material in mixing tank C, and then pump it into a high-speed shear emulsifier for secondary grinding with a grinding gap of 0.1 - 0.6 mm and a rotational speed of 5000 - 12000 rpm during grinding; then introduce the ground secondary mixed material into a finished product development tank and keep stirring at a temperature of 170 - 190°C for 45 - 80 minutes with a stirring rate of 500 - 1000 rpm to obtain a high-performance composite hydrated iron oxide activated rubber modified asphalt.

[0021] Further, the rubber powder is obtained by mechanically crushing waste tires or other rubber tires, removing steel wires and fibers, etc., and finally being crushed into rubber powder, preferably with a particle size of 80 - 100 mesh.

[0022] Further, the waste vegetable oil is the waste vegetable oil generated during the food processing process;

[0023] Further, the hydrated iron oxide is a lemon yellow to brown powder, insoluble in water and alcohol, soluble in acid, and its particle size is 50 - 100 nm; the asphalt is the asphalt commonly used in pavement engineering, preferably 70# asphalt.

[0024] Further, when performing sufficient grinding and shearing in Step Two, the rotational speed is 10000 rpm and the shearing time is 30 minutes.

[0025] Further, the conditions for pre-heating and pre-swelling development of the rubber powder in Step Three are: temperature 150°C, stirring at 500 rpm for 60 minutes.

[0026] Further, Step Four is specifically as follows:

[0027] Add mixture B to mixture A, and keep stirring at a temperature of 180°C for 30 min at a stirring rate of 500 rpm to form a secondary mixed material; pump the secondary mixed material into a high-speed shear emulsifier for primary grinding with a grinding gap of 0.8 - 1.5 mm and a rotational speed of 10,000 rpm during grinding; then introduce the ground secondary mixed material into mixing tank C and keep stirring at a temperature of 180°C for 30 min at a stirring rate of 1,500 rpm.

[0028] Further, step five is specifically as follows:

[0029] Then add hydrated iron oxide to the mixed material in mixing tank C, and then pump it into a high-speed shear emulsifier for secondary grinding with a grinding gap of 0.3 - 0.5 mm and a rotational speed of 10,000 rpm during grinding; then introduce the ground secondary mixed material into the finished product development tank and keep stirring at a temperature of 180°C for 60 min at a stirring rate of 1,000 rpm.

[0030] Compared with the prior art, the technical principle, advantages and beneficial effects of the technical solution of this application are as follows:

[0031] As an efficient activator, hydrated iron oxide enhances the surface activity of the rubber powder (the rubber powder in this invention refers to rubber powder) through chemical reactions, improves the compatibility and bonding force between the rubber powder and asphalt. This activation effect enables the rubber powder to disperse more uniformly in the asphalt matrix, forming a more stable composite structure, thereby improving the overall performance of the modified asphalt. Waste vegetable oil acts as a flexible enhancer in the formula. It can improve the compatibility between the rubber powder and asphalt, increase the flexibility of the mixture, and thus improve the low-temperature performance of the asphalt. In addition, waste vegetable oil can also delay the aging process of asphalt and extend the service life of the road. As a polymer, EVA has good elasticity and wear resistance. Introducing EVA into the rubber-modified asphalt can significantly improve the high-temperature stability of the asphalt and reduce the rutting and deformation phenomena of the road in high-temperature environments.

[0032] Through the settings of the preparation steps, the present invention can enable each raw material to achieve the best effect in the prepared rubber-modified asphalt. First, in the material mixing stage, heating and mixing the petroleum asphalt can fully dissolve and disperse the EVA, forming a uniform primary mixture A, and the mixing uniformity can be effectively improved during the shearing process. Next, in the stage of pre-swelling of the rubber powder, the rubber powder is fully swollen and dispersed to form a stable mixture B. In the first-stage grinding process, the mixture B is added to the mixture A for grinding to further refine and evenly distribute the materials. In the final second-stage grinding process, hydrated iron oxide is added to the secondary mixed materials for grinding to fully disperse and activate the materials, ensuring the stability and uniformity of the finished product. This multi-stage mixing and grinding process not only improves the high and low temperature stability of the materials, but also improves the production efficiency and reduces the energy consumption through reasonable temperature control and stirring rate. At the same time, the application of waste vegetable oil and waste tire rubber powder realizes the resource utilization of waste, which can not only significantly reduce the cost of road materials, but also reduce environmental pollution, with remarkable environmental protection benefits. The final product has excellent road performance and rheological properties, ensuring the performance stability during long-term use. These optimized configurations make the high-performance composite hydrated iron oxide-activated rubber-modified asphalt have a wide application prospect in road construction. Description of the Drawings

[0033] Figure 1 For the viscosity test results at 180°C in the embodiment;

[0034] Figure 2 For the softening point test results in the embodiment;

[0035] Figure 3 For the penetration test results at 25°C in the embodiment;

[0036] Figure 4 For the ductility test results at 5°C in the embodiment;

[0037] Figure 5 For the softening point difference test results at 96h in the embodiment. Detailed Description of the Embodiment

[0038] The following is a further detailed description through specific embodiments:

[0039] The present invention provides a high-performance composite hydrated iron oxide-activated rubber-modified asphalt, which includes the following raw materials: hydrated iron oxide, waste vegetable oil, rubber powder, EVA, asphalt;

[0040] Rubber powder is usually obtained from waste tires or other rubber products through processes such as mechanical crushing, removal of steel wires and fibers, and finally pulverized into rubber powder. The particle size of the rubber powder used in the examples is 80 - 100 mesh, and the manufacturer is: Hongrui Industrial Rubber Sales Department in Lantian County; waste vegetable oil is generated during the food processing process. The waste cooking oil in this invention is purchased from Shunxin Waste Oil Acquisition Team in Jinyuan District, Taiyuan City; hydrated iron oxide is a powder ranging from lemon yellow to brown, insoluble in water and alcohol, soluble in acid. The hydrated iron oxide used in the examples is purchased from Wuhan Kemike Biopharmaceutical Technology Co., Ltd., with a particle size of 50 - 100 nm; the petroleum asphalt used is the commonly used 70# asphalt in pavement engineering, purchased from China Petroleum & Chemical Corporation; EVA is an ethylene - vinyl acetate copolymer, purchased from Beijing Yanshan Petrochemical Co., Ltd. of China National Petroleum Corporation, with a density of 0.93 - 0.95 g / cm 3 , and the vinyl acetate VA content is 18 - 20 wt%.

[0041] The proportions of the raw materials in Examples 1 - 9 of the present invention are shown in Table 1.

[0042] Table 1

[0043]

[0044] Now, taking Example 1 as an example, the preparation method of the high - performance composite hydrated iron oxide activated rubber modified asphalt of the present invention will be described. Except for the parameters in Table 1, the preparation process and other parameters of Examples 2 - 9 are the same as those of Example 1.

[0045] The high - performance composite hydrated iron oxide activated rubber modified asphalt of the present invention is prepared through the following steps:

[0046] Step 1, material mixing

[0047] Put 100 g of petroleum asphalt into mixing tank A, heat the petroleum asphalt to 150 °C, then add 1 g of EVA thereto, and keep stirring at a stirring rate of 1000 rpm for 30 min to form a primary mixed material.

[0048] Step 2, high - speed shearing

[0049] Pump the primary mixed material into a high - speed shearing machine for grinding and shearing. The grinding speed is 10000 rpm, and the shearing time is 30 min to obtain mixture A.

[0050] Step 3, pre - swelling of rubber powder

[0051] Put 15 g of waste vegetable oil and 15 g of rubber powder into mixing tank B, heat to 150 °C, and stir for 60 min for pre - heat preservation and pre - swelling development of the rubber powder. The stirring rate is 500 rpm to obtain mixture B.

[0052] Step 4, primary grinding

[0053] Add mixture B to mixture A, and keep stirring at 180 °C for 30 min at a stirring rate of 500 rpm to form a secondary mixed material; pump the secondary mixed material into a high-speed shear emulsifier for primary grinding with a grinding gap of 0.8 mm and a rotational speed of 10,000 rpm during grinding; then introduce the ground secondary mixed material into mixing tank C and keep stirring at 180 °C for 30 min at a stirring rate of 1500 rpm.

[0054] Step 5, secondary grinding

[0055] Add 1 g of hydrated iron oxide to the secondary mixed material in mixing tank C, then pump it into a high-speed shear emulsifier for secondary grinding with a grinding gap of 0.3 mm and a rotational speed of 10,000 rpm during grinding; then introduce the ground secondary mixed material into the finished product development tank and keep stirring at 180 °C for 60 min at a stirring rate of 1000 rpm, and then conduct inspections. After passing the inspections, a rubber-modified asphalt product with high storage stability is formed.

[0056] The ratios of the parameters of Comparative Examples 1-6 of the present invention are shown in Table 2.

[0057] The rubber-modified asphalt in Comparative Examples 1-3 is prepared through the following steps:

[0058] Put petroleum asphalt into the mixing tank, heat the petroleum asphalt to 180 °C, then put rubber powder into it, and keep stirring at 180 °C for 60 min at a stirring rate of 5000 rpm without primary grinding and secondary grinding to obtain rubber-modified asphalt.

[0059] The rubber-modified asphalt in Comparative Examples 4-6 is prepared through the following steps:

[0060] Put petroleum asphalt into the mixing tank, heat the petroleum asphalt to 180 °C, then put rubber powder into it, and keep stirring at 180 °C for 30 min at a stirring rate of 500 rpm, pump it into a high-speed shear emulsifier for primary grinding with a grinding gap of 1.5 mm and a rotational speed of 10,000 rpm during grinding; then introduce the ground mixed material into mixing tank C and keep stirring at 180 °C for 30 min at a stirring rate of 1500 rpm.

[0061] Table 2

[0062]

[0063] Taking JTG F40-2004 "Technical Specification for Construction of Highway Asphalt Pavements" as the test basis, the rubber-modified asphalt prepared in Examples 1-9 and Comparative Examples 1-6 was tested, and the data shown in Table 3 were obtained.

[0064] Table 3

[0065]

[0066] According to the data in Table 3 and Figures 1-5 , the high-performance composite hydrated iron oxide-activated rubber-modified asphalt provided by the present invention has lower viscosity, higher softening point and lower penetration than Comparative Examples 1-6, and has excellent storage stability. These advantages are attributed to the improvement of the overall performance of rubber-modified asphalt by the composite modification of hydrated iron oxide, waste vegetable oil and EVA. Among them, hydrated iron oxide dehydrates under high-temperature conditions to form microbubbles in the crumb rubber asphalt, effectively reducing the viscosity of the modified asphalt. At the same time, hydrated iron oxide and waste vegetable oil can effectively decompose the sulfides in the crumb rubber, activate the crumb rubber, and thus improve the comprehensive performance of the rubber-modified asphalt. In addition, the combined action of waste vegetable oil and EVA reduces the softening point difference of the rubber-modified asphalt at 96 h, which indicates that the storage stability of the high-performance composite hydrated iron oxide-activated rubber-modified asphalt provided by the present invention is significantly improved. In summary, the temperature indicators such as softening point, ductility and penetration of the high-performance composite hydrated iron oxide-activated rubber-modified asphalt provided by the present invention are significantly improved, and at the same time, the corresponding indicators of its storage stability are also improved, and its preparation process is relatively simple and easy to implement.

[0067] For those skilled in the art, without departing from the concept of the technical solution of the present invention, several deformations and improvements can also be made, which should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect and practicability of the technical solution of this application.

Claims

1. A high-performance composite hydrated iron oxide activated rubber-modified asphalt, comprising the following raw materials: hydrated iron oxide, waste vegetable oil, rubber powder, ethylene-vinyl acetate copolymer (EVA), and asphalt, wherein the mass ratio of the hydrated iron oxide, waste vegetable oil, rubber powder, EVA, and asphalt is (1-5):(15-20):(15-20):(1-5):100; the waste vegetable oil is waste vegetable oil generated during food processing; The preparation method of the high-performance composite hydrated iron oxide activated rubber modified asphalt comprises the following specific steps: Step 1: Material mixing Heat and melt the asphalt in the mixing tank A, then add EVA, keep warm and stir until the mixture is evenly mixed to form a primary mixed material; Step 2: High-speed shearing The primary mixed material is pumped into a high-speed shearing machine for thorough grinding and shearing to obtain a mixture A; Step 3: Pre-swelling of rubber powder Place waste vegetable oil and rubber powder in a mixing tank B, heat to 150-180°C, and stir to pre-insulate and pre-swell the rubber powder to obtain a mixture B; Step 4: First-level grinding Adding mixture B to mixture A, and stirring at a temperature of 170-190° C. for 20-45 minutes at a stirring rate of 500-800 rpm to form a secondary mixture; pumping the secondary mixture into a high-speed shear emulsifier for primary grinding with a grinding gap of 0.8-1.5 mm and a grinding speed of 5000-12000 rpm; then introducing the ground secondary mixture into mixing tank C, and stirring at a temperature of 170-190° C. for 30-45 minutes at a stirring rate of 1000-1500 rpm; Step 5: Secondary grinding Then, hydrated iron oxide is added to the mixture in mixing tank C, and then pumped into a high-speed shear emulsifier for secondary grinding. The grinding gap is 0.3-0.5 mm and the rotation speed during grinding is 5000-12000 rpm. The ground secondary mixture is then introduced into a finished product development tank and stirred at a temperature of 170-190°C for 45-80 minutes at a stirring rate of 500-1000 rpm to obtain high-performance composite hydrated iron oxide activated rubber modified asphalt.

2. The high-performance composite hydrated iron oxide activated rubber modified asphalt according to claim 1, characterized in that: The particle size of the rubber powder is 80-100 meshes, the particle size of the hydrated iron oxide is 50-100 nm, and the asphalt is asphalt commonly used in paving projects.

3. The high-performance composite hydrated iron oxide activated rubber modified asphalt according to claim 1, characterized in that: When fully grinding and shearing are performed in step 2, the rotation speed is 10000 rpm and the shearing time is 30 minutes.

4. The high-performance composite hydrated iron oxide activated rubber modified asphalt according to claim 1, characterized in that: The conditions for pre-insulation and pre-swelling of the rubber powder in step 3 are: temperature 150° C., stirring at 500 rpm for 60 minutes.

5. The high-performance composite hydrated iron oxide activated rubber modified asphalt according to claim 1, characterized in that: The step 4 is specifically as follows: Add mixture B to mixture A, and stir at a temperature of 180°C for 30 minutes at a stirring rate of 500 rpm to form a secondary mixture; pump the secondary mixture into a high-speed shear emulsifier for primary grinding with a grinding gap of 0.8-1.5 mm and a grinding speed of 10,000 rpm; then introduce the ground secondary mixture into a mixing tank C, and stir at a temperature of 180°C for 30 minutes at a stirring rate of 1,500 rpm.

6. The high-performance composite hydrated iron oxide activated rubber modified asphalt according to claim 1, characterized in that: The step five is specifically as follows: Then add hydrated iron oxide to the mixed material in mixing tank C, and then pump it into a high-speed shear emulsifier for secondary grinding. The grinding gap is 0.3-0.5mm and the grinding speed is 10000rpm. The ground secondary mixed material is then introduced into the finished product development tank and kept warm and stirred at a temperature of 180°C for 60 minutes at a stirring rate of 1000rpm.

Images