Semi-crosslinked warm mix rubber powder modified asphalt and preparation method thereof

Abstract

The present invention belongs to the technical field of asphalt pavement materials, and specifically discloses a semi-crosslinked warm mix rubber powder modified asphalt and a preparation method thereof. The preparation method of the semi-crosslinked warm mix rubber powder modified asphalt of the present invention comprises the following steps: 1) by weight, 20 parts of waste rubber powder are mixed with 2-4 parts of pre-swelling agent, and developed at 75°C for 15 minutes to obtain pre-swelled waste rubber powder; 2) the pre-swelled waste rubber powder obtained in step 1) is mixed with 4-10 parts of protective agent, and developed at 110°C for 15 minutes to obtain semi-crosslinked pre-swelled waste rubber powder; 3) the semi-crosslinked pre-swelled waste rubber powder obtained in step 2), 0.5-1 parts of anti-stripping agent, 0.5-1 parts of dispersant and 100 parts of base asphalt are mixed, and sheared at 160°C and 1000rpm for 1 hour to obtain semi-crosslinked warm mix rubber powder modified asphalt. The rubber powder modified asphalt prepared by the present invention has low viscosity, good high and low temperature performance, and good storage stability.

Description

Technical Field

[0001] The invention belongs to the technical field of asphalt pavement materials, and in particular relates to a semi-crosslinked warm mix rubber powder modified asphalt and a preparation method thereof. Background Art

[0002] As an environmentally friendly pavement material, rubber powder modified asphalt can not only improve the high and low temperature performance of asphalt pavement, but also effectively reduce road noise. However, high viscosity and poor storage stability seriously affect the application of rubber powder modified asphalt. The cross-linking and interaction between rubber powder particles and asphalt first increase and then decrease as the swelling degree of rubber powder particles increases. This is because after the rubber powder particles are fully swollen, the soluble substances inside are completely integrated into the asphalt, and the remaining substances in the rubber powder particles are mostly solid insolubles, which reduces the interaction ability between asphalt and rubber powder, thereby making the performance of rubber powder modified asphalt worse. At the same time, the integrity of the rubber powder particle structure seriously affects the performance of rubber powder modified asphalt. After full swelling, the high and low temperature performance of rubber powder modified asphalt has decreased. This is because the structure of the rubber powder particles is no longer complete and cannot resist external forces.

[0003] An existing patent application (CN108659558A) has proposed a better solution for reducing the viscosity of rubber powder modified asphalt, but it has no better positive impact on high and low temperature performance. Its relatively cumbersome preparation scheme and long production time lead to high energy consumption and more serious degradation of rubber powder particles. As a result, it has a high cost but does not effectively improve the performance of rubber powder modified asphalt. The patent application that has been published (CN 114213855A) proposes a method that can improve high and low temperature performance and reduce mixing viscosity, but because its more lightweight components destroy the structure of the rubber powder particles themselves, resulting in its elastic recovery ability deteriorating. This shows that a good production method and material selection have positive significance for the performance of rubber powder modified asphalt.

[0004] Patent application (CN115304841A) discloses a pre-treated rubber powder for high-volume rubber-modified asphalt and a preparation method thereof. The pre-swelling and desulfurization scheme requires high temperature, high pressure and a long time, which requires more professional equipment and higher costs.

[0005] The present invention is proposed to solve the problems of the existing rubber powder modified asphalt, such as complicated production method, high viscosity, poor high and low temperature performance, and low storage stability. Summary of the invention

[0006] The object of the present invention is to provide a semi-crosslinked warm mix rubber powder modified asphalt and a preparation method thereof. The rubber powder modified asphalt prepared by the present invention has the characteristics of easy production and construction, good high and low temperature performance, good storage stability and low viscosity. This can not only improve the pavement performance, reduce the paving cost, but also reduce energy consumption. It has the characteristics of low energy consumption, low viscosity, easy production and construction and high performance.

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

[0008] A semi-crosslinked warm mix rubber powder modified asphalt is prepared from the following raw materials by weight: 100 parts of base asphalt, 20 parts of waste rubber powder, 2-4 parts of pre-swelling agent, 4-10 parts of protective agent, 0.5-1 part of anti-stripping agent and 0.5-1 part of dispersant.

[0009] Preferably, a semi-cross-linked warm mix rubber powder modified asphalt is made of the following raw materials, calculated by weight: 100 parts of base asphalt, 20 parts of waste rubber powder, 2 to 4 parts of pre-swelling agent, 4 to 8 parts of protective agent, 0.5 to 1 part of anti-stripping agent and 0.5 to 1 part of dispersant.

[0010] More preferably, a semi-cross-linked warm mix rubber powder modified asphalt is made from the following raw materials, calculated by weight: 100 parts of base asphalt, 20 parts of waste rubber powder, 2 to 4 parts of pre-swelling agent, 4 to 6 parts of protective agent, 0.5 to 1 part of anti-stripping agent and 0.5 to 1 part of dispersant.

[0011] The most preferred embodiment is a semi-cross-linked warm mix rubber powder modified asphalt, which is made of the following raw materials, by mass: 100 parts of base asphalt, 20 parts of waste rubber powder, 4 parts of pre-swelling agent, 4 parts of protective agent, 0.5-1 part of anti-stripping agent and 0.5-1 part of dispersant.

[0012] Furthermore, the asphalt is 70# base asphalt.

[0013] Furthermore, the waste rubber powder is the waste rubber powder commonly used in construction mixing stations, the particle size of the waste rubber powder is 0.125mm-0.85mm, and the particle size of the waste rubber powder is less than 0.425mm, accounting for 60%-70%.

[0014] Furthermore, the pre-swelling agent is environmentally friendly aromatic oil and / or cycloalkyl rubber oil; preferably, the pre-swelling agent is a mixture of environmentally friendly aromatic oil and cycloalkyl rubber oil; more preferably, the pre-swelling agent is a mixture of environmentally friendly aromatic oil and cycloalkyl rubber oil in a mass ratio of 1:2.

[0015] Furthermore, the protective agent is a mixture of a silane coupling agent and an isolating agent in a mass ratio of 1:1; the silane coupling agent is selected from any one of KH-500, KH-550 and KH-570; the isolating agent is selected from any one of RH warm mix agent, ethylene bis stearamide (EBS) and polypropylene wax (preferably with a molecular weight of 2000-3000). The RH warm mix agent is developed by the Highway Research Institute of the Ministry of Transport, and is composed of 30-80% of the total weight of cracked polyethylene wax (PE wax) and 20-70% of the total weight of stearic acid, wherein the cracked polyethylene wax is obtained by high-temperature cracking of low-density polyethylene.

[0016] Furthermore, the anti-stripping agent is selected from any one of Zycosoil nano anti-stripping agent, monododecyl phosphate and phosphoglyceride; preferably, the anti-stripping agent is Zycosoil nano anti-stripping agent.

[0017] Furthermore, the dispersant is selected from any one of octavinyl cage-shaped polysilsesquioxide (OvPOSS), polyethylene and graphene.

[0018] The present invention also discloses a method for preparing the semi-cross-linked warm mix rubber powder modified asphalt, comprising the following steps:

[0019] 1) Mix 20 parts of waste rubber powder with 2-4 parts of pre-swelling agent by weight, and develop at 75°C for 15 minutes to prepare pre-swelling waste rubber powder;

[0020] 2) mixing the pre-swelled waste rubber powder obtained in step 1) with 4 to 10 parts of a protective agent, and developing at 110° C. for 15 minutes to obtain a semi-crosslinked pre-swelled waste rubber powder;

[0021] 3) The semi-crosslinked pre-swollen waste rubber powder obtained in step 2), 0.5-1 part of anti-stripping agent, 0.5-1 part of dispersant and 100 parts of base asphalt are mixed, and sheared at 160° C. and 1000 rpm for 1 hour to obtain semi-crosslinked warm mix rubber powder modified asphalt.

[0022] The beneficial effects of the present invention are:

[0023] The semi-crosslinked warm mix rubber powder modified asphalt prepared by the present invention enhances its high and low temperature performance, improves its storage stability, and reduces the construction production, mixing and paving temperature. The production method of the present invention is simple, the rubber powder modified asphalt has excellent performance and less energy consumption, has good development prospects, and especially has the following advantages:

[0024] (1) The pre-swelling process at low temperature makes the rubber powder particles swell in advance and reduces the degradation of the rubber powder particles during the pre-swelling process. Since the interaction between the rubber powder particles and the light components gradually moves from the outside to the inside, the appropriate light component content and reaction time can protect the integrity of the rubber powder particle structure while ensuring good interaction between the rubber powder particles and asphalt, so that the performance of the final product is in the best state. The pre-swelling agent is all light oil. During shearing, the rubber powder particles will be broken, and part of the pre-swelling agent will return to the asphalt to increase the content of light components in the asphalt, thereby showing viscosity reduction ability.

[0025] (2) Protective treatment is performed on the rubber powder particles to reduce the soluble substances inside the rubber powder particles from entering the asphalt, ensuring the integrity of the rubber powder particle structure. The silane coupling agent is wrapped around the surface of the rubber powder particles to block the interaction between the rubber powder particles and the asphalt, replace the interaction interface between the rubber powder particles and the asphalt, and improve the tightness of the combination between the two. Taking the RH warm mix agent as an example of the isolation agent, the RH warm mix agent blocks the interaction between the rubber powder particles and the asphalt, protecting the integrity of the rubber powder particle structure. At the same time, the RH warm mix agent is on the surface of the rubber particles, reducing the friction between the rubber powder particles to achieve the purpose of reducing viscosity. Mixing the protective agent with the rubber powder particles in advance can make the protective agent and the rubber powder particles more tightly combined. At this time, part of the surface of the rubber powder particles is silane coupling agent, part is RH warm mix agent, and the remaining part is the original surface of the rubber powder. Silane coupling agent makes the rubber powder particles and asphalt combine more tightly, and RH warm mix agent makes it impossible for rubber powder particles and asphalt to contact and combine. The remaining part is the normal contact surface between rubber powder particles and asphalt. At this time, part of the surface of rubber powder particles is cross-linked with asphalt, and part of the surface of rubber powder particles cannot be cross-linked with asphalt, which is in a semi-cross-linked state. The purpose of blocking the interaction between rubber powder particles and asphalt is to protect the structural integrity of rubber powder particles and improve the high and low temperature performance of rubber powder modified asphalt. Ethylene bis stearamide (EBS) and polypropylene wax can play a similar role as RH warm mix agent because they will be firmly adsorbed on the surface of rubber powder particles during the mixing process to play a lubricating and isolating role.

[0026] (3) Anti-stripping agent can make up for the reduction of anti-stripping performance caused by the soluble substances in the rubber powder not entering the asphalt phase.

[0027] (4) Dispersants can better disperse the four components of asphalt and rubber powder particles in the rubber powder modified asphalt, thereby improving storage stability. More uniform distribution reduces intermolecular friction and agglomeration of heavy components, thereby reducing viscosity.

[0028] (5) The introduction of additives reduces the viscosity of rubber-powder modified asphalt, thereby reducing the production and paving temperature of rubber-powder modified asphalt, reducing the generation of harmful gases and energy consumption.

[0029] (6) The production method of the present invention is simple, closer to actual production needs, and helps to improve product quality under unchanged production conditions. Therefore, the semi-cross-linked warm mix rubber powder modified asphalt has a good development prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is an appearance diagram of the waste rubber powder used in the present invention;

[0031] Figure 2 This is an appearance diagram of the pre-swollen waste rubber powder prepared by the present invention;

[0032] Figure 3 This is an appearance diagram of the semi-crosslinked pre-swollen waste rubber powder prepared by the present invention;

[0033] Figure 4 This is a shearing process diagram for preparing semi-cross-linked warm mix rubber powder modified asphalt according to the present invention;

[0034] Figure 5 This is a SEM image of the waste rubber powder particles used in the present invention (magnified 2000X);

[0035] Figure 6 This is a SEM image of the pre-swollen waste rubber powder particles prepared in Example 3 of the present invention (magnified 2000X);

[0036] Figure 7 This is a microscope image (magnification 40X) of the pre-swollen waste rubber powder particles prepared in Example 3 of the present invention;

[0037] Figure 8 This is a microscope picture (magnification 100X) of the semi-cross-linked warm mix rubber powder modified asphalt prepared in Comparative Example 5 of the present invention.

[0038] Depend on Figure 5 and Figure 6 It can be seen that after pre-swelling, the surface of the rubber powder particles is fuller, the grooves disappear, and only some particles protrude, which proves that the pre-swelling degree is good. Figure 7 Microscope volume observation shows that the volume of the rubber powder particles added with 20% of the rubber powder mass pre-swelling agent at 75°C does not change after pre-swelling for 15 minutes, proving that it has been fully pre-swollen at 15 minutes. DETAILED DESCRIPTION

[0039] The applicant further describes the technical solution of the present invention in conjunction with specific embodiments below, but the scope of protection requested by the claims of the present invention is not limited to these embodiments.

[0040] In the following examples and comparative examples, the base asphalt used is 70# base asphalt;

[0041] The waste rubber powder used is the waste rubber powder commonly used in construction mixing stations. Figure 1, SEM images are shown in Figure 5 , its particle size is graded distribution, the particle size distribution is shown in Table 1:

[0042] Table 1 Waste rubber powder particle gradation distribution table

[0043] Screen size (mm) Pass Rate % 0.85 100 0.425 60-70 0.25 30-40 0.18 15-25 0.15 10-20 0.125 0-10 0.106 0

[0044] The environmentally friendly aromatic oil used was purchased from Kaixuan Plastic Technology Co., Ltd.;

[0045] The cycloalkyl rubber oil used was purchased from Jinan Luying Chemical Co., Ltd., model KN4006;

[0046] The silane coupling agent used was purchased from Gabite (Guangzhou) New Materials Co., Ltd., model KH550;

[0047] The RH warm mix agent used is developed by the Highway Research Institute of the Ministry of Transport, and is composed of 30-80% of the total weight of pyrolysis polyethylene wax (PE wax) and 20-70% of the total weight of stearic acid, wherein the pyrolysis polyethylene wax is obtained by high-temperature pyrolysis of low-density polyethylene.

[0048] The EBS (ethylene bis stearamide) used was purchased from Shanghai Yunhe Material Technology Co., Ltd.

[0049] The Fischer-Tropsch wax used was purchased from Shijiazhuang Changyao Chemical Co., Ltd.;

[0050] The anti-stripping agent used is Zycosoil nano anti-stripping agent;

[0051] The dispersant used was octavinyl cage-shaped polysilsesquioxide (OvPOSS).

[0052] In the following examples and comparative examples, each mass portion was tested on a 3 g scale.

[0053] Embodiment 1

[0054] A semi-cross-linked warm mix rubber powder modified asphalt is made of the following raw materials by weight: 100 parts of base asphalt, 20 parts of waste rubber powder, 2 parts of pre-swelling agent, 4 parts of protective agent, 1 part of anti-stripping agent and 1 part of dispersant. The pre-swelling agent used is a mixture of environmentally friendly aromatic oil and cycloalkyl rubber oil in a mass ratio of 1:2, and the protective agent used is a mixture of silane coupling agent and RH warm mix agent in a mass ratio of 1:1. The preparation method thereof comprises the following steps:

[0055] (1) By weight, 20 parts of waste rubber powder and 2 parts of pre-swelling agent were mixed and grown at 75°C for 15 minutes to prepare pre-swelled waste rubber powder.

[0056] (2) The pre-swollen scrap rubber powder prepared in (1) was mixed with 4 parts of a protective agent and grown at 110° C. for 15 minutes to obtain a semi-crosslinked pre-swollen scrap rubber powder.

[0057] (3) The semi-crosslinked pre-swollen waste rubber powder obtained in (2) is mixed with 1 part of an anti-stripping agent, 1 part of a dispersant and 100 parts of a base asphalt, and sheared at 160° C. and 1000 rpm for 1 hour to obtain a semi-crosslinked warm mix rubber powder modified asphalt.

[0058] Embodiment 2

[0059] A semi-crosslinked warm mix rubber powder modified asphalt is prepared from the following raw materials by weight: 100 parts of base asphalt, 20 parts of waste rubber powder, 2 parts of pre-swelling agent, 4 parts of protective agent, 0.5 parts of anti-stripping agent and 0.5 parts of dispersant. The pre-swelling agent used is a mixture of environmentally friendly aromatic oil and cycloalkyl rubber oil in a mass ratio of 1:2, and the protective agent used is a mixture of silane coupling agent and RH warm mix agent in a mass ratio of 1:1. The preparation method is the same as that of Example 1.

[0060] Embodiment 3

[0061] A semi-crosslinked warm mix rubber powder modified asphalt is prepared from the following raw materials by weight: 100 parts of base asphalt, 20 parts of waste rubber powder, 4 parts of pre-swelling agent, 4 parts of protective agent, 0.5 parts of anti-stripping agent and 0.5 parts of dispersant. The pre-swelling agent used is a mixture of environmentally friendly aromatic oil and cycloalkyl rubber oil in a mass ratio of 1:2, and the protective agent used is a mixture of silane coupling agent and RH warm mix agent in a mass ratio of 1:1. The preparation method is the same as that of Example 1.

[0062] Embodiment 4

[0063] A semi-crosslinked warm mix rubber powder modified asphalt is prepared from the following raw materials by weight: 100 parts of base asphalt, 20 parts of waste rubber powder, 4 parts of pre-swelling agent, 6 parts of protective agent, 0.5 parts of anti-stripping agent and 0.5 parts of dispersant. The pre-swelling agent used is a mixture of environmentally friendly aromatic oil and cycloalkyl rubber oil in a mass ratio of 1:2, and the protective agent used is a mixture of silane coupling agent and RH warm mix agent in a mass ratio of 1:1. The preparation method is the same as that of Example 1.

[0064] Embodiment 5

[0065] A semi-cross-linked warm mix rubber powder modified asphalt is made of the following raw materials by weight: 100 parts of base asphalt, 20 parts of waste rubber powder, 4 parts of pre-swelling agent, 4 parts of protective agent, 0.5 parts of anti-stripping agent and 0.5 parts of dispersant. The pre-swelling agent used is environmentally friendly aromatic oil, and the protective agent used is a mixture of silane coupling agent and RH warm mix agent in a mass ratio of 1:1. Compared with Example 3, the formula uses a different pre-swelling agent. The preparation method is basically the same as Example 3, except that the raw materials of the pre-swelling agent used are different.

[0066] Embodiment 6

[0067] A semi-crosslinked warm mix rubber powder modified asphalt is made of the following raw materials by weight: 100 parts of base asphalt, 20 parts of waste rubber powder, 4 parts of pre-swelling agent, 4 parts of protective agent, 0.5 parts of anti-stripping agent and 0.5 parts of dispersant. The pre-swelling agent used is cycloalkyl rubber oil, and the protective agent used is a mixture of silane coupling agent and RH warm mix agent in a mass ratio of 1:1. Compared with Example 3, the formula uses a different pre-swelling agent. The preparation method is basically the same as Example 3, except that the raw materials of the pre-swelling agent used are different.

[0068] Embodiment 7

[0069] A semi-cross-linked warm mix rubber powder modified asphalt is made of the following raw materials by weight: 100 parts of base asphalt, 20 parts of waste rubber powder, 4 parts of pre-swelling agent, 4 parts of protective agent, 0.5 parts of anti-stripping agent and 0.5 parts of dispersant. The pre-swelling agent used is a mixture of environmentally friendly aromatic oil and cycloalkyl rubber oil in a mass ratio of 1:2, and the protective agent used is a mixture of silane coupling agent and EBS in a mass ratio of 1:1. Compared with Example 3, the protective agent used in its formula is different. Its preparation method is basically the same as Example 3, except that the raw materials of the protective agent used are different.

[0070] Comparative Example 1

[0071] A rubber powder modified asphalt is prepared from the following raw materials by weight: 100 parts of base asphalt and 20 parts of waste rubber powder. The preparation method thereof comprises the following steps:

[0072] 20 parts of waste rubber powder were grown at 75℃ for 15 minutes, then grown at 110℃ for 15 minutes, and then mixed with 100 parts of base asphalt. Rubber powder modified asphalt was obtained by shearing at 160℃ and 1000rpm for 1 hour.

[0073] Comparative Example 2

[0074] A warm mix rubber powder modified asphalt, whose formula is the same as that of Example 3, and the difference from Example 3 is that the preparation method is different, and the preparation method is:

[0075] All components are mixed and sheared at 160°C and 1000 rpm for 1 hour to obtain warm mix rubber powder modified asphalt.

[0076] Comparative Example 3

[0077] A semi-crosslinked warm mix rubber powder modified asphalt is prepared from the following raw materials by weight: 100 parts of base asphalt, 20 parts of waste rubber powder, 10 parts of pre-swelling agent, 4 parts of protective agent, 0.5 parts of anti-stripping agent and 0.5 parts of dispersant. The pre-swelling agent used is a mixture of environmentally friendly aromatic oil and cycloalkyl rubber oil in a mass ratio of 1:2, and the protective agent used is a mixture of silane coupling agent and RH warm mix agent in a mass ratio of 1:1. The preparation method is basically the same as that of Example 1, except that the amount of the pre-swelling agent used is different.

[0078] Comparative Example 4

[0079] A semi-crosslinked warm mix rubber powder modified asphalt is prepared from the following raw materials by weight: 100 parts of base asphalt, 20 parts of waste rubber powder, 4 parts of pre-swelling agent, 10 parts of protective agent, 0.5 parts of anti-stripping agent and 0.5 parts of dispersant. The pre-swelling agent used is a mixture of environmentally friendly aromatic oil and cycloalkyl rubber oil in a mass ratio of 1:2, and the protective agent used is a mixture of silane coupling agent and RH warm mix agent in a mass ratio of 1:1. The preparation method is basically the same as that of Example 1, except that the amount of the protective agent used is different.

[0080] Comparative Example 5

[0081] A semi-cross-linked warm mix rubber powder modified asphalt is made of the following raw materials by weight: 100 parts of base asphalt, 20 parts of waste rubber powder, 4 parts of pre-swelling agent, 4 parts of protective agent, 0.5 parts of anti-stripping agent and 0.5 parts of dispersant. The pre-swelling agent used is a mixture of environmentally friendly aromatic oil and cycloalkyl rubber oil in a mass ratio of 1:2, and the protective agent used is a mixture of silane coupling agent and Fischer-Tropsch wax in a mass ratio of 1:1. Compared with Example 5, the protective agent used in its formula is different. Its preparation method is basically the same as that of Example 3, except that the raw materials of the protective agent used are different.

[0082] The performance results of the rubber powder modified asphalt prepared in the above examples and comparative examples are shown in Table 2:

[0083] Table 2 Experimental results of rubber powder modified asphalt performance

[0084]

[0085]

[0086] Table 2 shows the performance data of the embodiments and comparative examples. It can be seen from Table 2 that:

[0087] Comparison between Example 1 and Example 2 shows that more dispersants and anti-stripping agents have less effect on the performance of semi-cross-linked warm mix rubber powder modified asphalt, and Example 2 already has better performance. Comparison between Example 2 and Example 3 and Comparative Example 3 shows that when the pre-swelling agent exceeds 4% of the asphalt content, the high and low temperature performance and adhesion grade of the rubber powder modified asphalt will be reduced, that is, too much pre-swelling agent has an adverse effect on the performance of semi-cross-linked warm mix rubber powder modified asphalt. Considering all the properties comprehensively, the pre-swelling agent dosage is 2% to 4% of the asphalt content. Comparison between Example 3 and Example 4 and Comparative Example 4 shows that as the amount of protective agent increases, the viscosity decreases, the high temperature performance improves, and the low temperature performance decreases. If used in high temperature areas, the recommended protective agent dosage is 4% to 10% of the asphalt content; if all the properties are considered comprehensively, the recommended protective agent dosage is 4% to 8% of the asphalt content, and 4% to 6% is better.

[0088] The performance of each embodiment is better than that of the comparative example 1, which shows that the selection and proper addition of additives in the present invention can effectively reduce the viscosity and improve the performance of the rubber powder modified asphalt.

[0089] It can be seen from Comparative Example 2 and Example 3 that the rubber powder particles swell and degrade to a higher degree when directly mixed, and a good particle structure cannot be maintained. At the same time, since the additives cannot be pre-combined with the rubber powder particles when directly added, the degree of binding is not tight enough. As a result, the viscosity in Comparative Example 2 increases, and the high and low temperature performance decreases. Since the rubber powder particles are not wrapped by the protective agent, the density difference between the rubber powder particles and the asphalt phase becomes larger, thereby reducing the storage stability of Comparative Example 2.

[0090] Comparison between Example 3, Example 5 and Example 6 shows that a single pre-swelling agent has a performance bias, and a more balanced performance can be obtained by mixing the two. The environmentally friendly aromatic oil has poor viscosity reduction and high temperature capabilities, while the cycloalkyl rubber oil has poor low temperature performance and storage stability. After the two are mixed, the viscosity reduction and high temperature capabilities of the environmentally friendly aromatic oil are improved by the cycloalkyl rubber oil, and the low temperature performance and storage stability of the cycloalkyl rubber oil are compensated by the aromatic oil. At the same time, after the two are mixed, the storage stability of the rubber powder modified asphalt is further improved, proving that the mixture of the two has a more balanced and better performance.

[0091] Comparing Example 3 with Example 7, it is found that EBS can more effectively reduce viscosity and improve high temperature performance, but its low temperature performance and storage stability are slightly worse. This is because EBS contains C=O bonds, which have higher polarity, resulting in higher intermolecular aggregation, thereby improving high temperature performance and reducing low temperature performance. However, due to its excellent lubricity, its viscosity reduction effect is better.

[0092] Compared with the comparative example 5, the Fischer-Tropsch wax in the embodiment 3 cannot be effectively coated on the surface of the rubber powder particles like the RH warm mix agent, and the Fischer-Tropsch wax gradually separates from the surface of the rubber powder particles during the shearing process, and the structure of the rubber powder particles cannot be effectively maintained. At the same time, due to the lack of effective protection, the average particle size of the rubber powder particles is reduced, and the smaller rubber powder particles will enter the degradation stage earlier. This makes the performance of the comparative example 5 lag behind that of the embodiment 3 in all aspects. Figure 8 This is a microscope picture (magnification 100X) of the semi-cross-linked warm mix rubber powder modified asphalt prepared in Comparative Example 5 of the present invention. Figure 8 The substance in the red circle is Fischer-Tropsch wax, which falls off after shearing. At this time, the size of the substance in the red circle is comparable to the size of the rubber powder particles, but there is no black rubber powder particle insoluble matter around it, so it is the Fischer-Tropsch wax that is wrapped on the surface of the rubber powder particles and falls off. At the same time, studies have shown that the addition of Fischer-Tropsch wax does not prevent the interaction between rubber powder particles and components in asphalt, further indicating that Fischer-Tropsch wax has no protective effect.

[0093] The performance test is described as follows:

[0094] The test procedures for asphalt and asphalt mixtures in highway engineering JTGE20-2011 shall be followed; specifically:

[0095] (1) Brookfield viscosity at 160°C / Pa·s: Executed in accordance with T0625; asphalt rotational viscosity test (Brookfield viscometer method);

[0096] (2) Softening point / ℃: According to T0606; Asphalt softening point test (ring and ball method);

[0097] (3) 5℃ fracture work / N·mm: according to T0605; asphalt ductility test;

[0098] (4) Separation index: according to T0661; polymer modified asphalt separation test;

[0099] (5) Adhesion grade: in accordance with T0616; adhesion test of asphalt and coarse aggregate.

Claims

1. A semi-crosslinked warm mix rubber powder modified asphalt, characterized in that: The material is prepared from the following raw materials by weight: 100 parts of base asphalt, 20 parts of waste rubber powder, 2-4 parts of pre-swelling agent, 4-10 parts of protective agent, 0.5-1 part of anti-stripping agent and 0.5-1 part of dispersant. The preparation method comprises the following steps: 1) Mix the waste rubber powder with the pre-swelling agent and develop at 75°C for 15 minutes to obtain the pre-swelling waste rubber powder; 2) mixing the pre-swelled waste rubber powder obtained in step 1) with a protective agent, and developing at 110° C. for 15 minutes to obtain a semi-crosslinked pre-swelled waste rubber powder; 3) The semi-crosslinked pre-swollen waste rubber powder, anti-stripping agent, dispersant and base asphalt prepared in step 2) are mixed, and sheared at 160° C. and 1000 rpm for 1 hour to obtain semi-crosslinked warm mix rubber powder modified asphalt; The pre-swelling agent is environmentally friendly aromatic oil and / or naphthenic rubber oil; The protective agent is a mixture of a silane coupling agent and an isolating agent in a mass ratio of 1:1; the isolating agent is selected from any one of RH warm mix agent, ethylene bis stearamide and polypropylene wax; The RH warm mix agent is composed of 30%-80% of the total weight of cracked polyethylene wax and 20%-70% of the total weight of stearic acid, wherein the cracked polyethylene wax is obtained by high-temperature cracking of low-density polyethylene.

2. The semi-crosslinked warm mix rubber powder modified asphalt according to claim 1, characterized in that: It is made of the following raw materials in parts by mass: 100 parts of base asphalt, 20 parts of waste rubber powder, 2 to 4 parts of pre-swelling agent, 4 to 8 parts of protective agent, 0.5 to 1 part of anti-stripping agent and 0.5 to 1 part of dispersant.

3. The semi-crosslinked warm mix rubber powder modified asphalt according to claim 1, characterized in that: It is made of the following raw materials in parts by mass: 100 parts of base asphalt, 20 parts of waste rubber powder, 2 to 4 parts of pre-swelling agent, 4 to 6 parts of protective agent, 0.5 to 1 part of anti-stripping agent and 0.5 to 1 part of dispersant.

4. The semi-crosslinked warm mix rubber powder modified asphalt according to claim 1, characterized in that: It is made of the following raw materials, calculated by weight: 100 parts of base asphalt, 20 parts of waste rubber powder, 4 parts of pre-swelling agent, 4 parts of protective agent, 0.5-1 parts of anti-stripping agent and 0.5-1 parts of dispersant.

5. The semi-crosslinked warm mix rubber powder modified asphalt according to claim 1, characterized in that: The pre-swelling agent is a mixture of environmentally friendly aromatic oil and naphthenic rubber oil.

6. The semi-crosslinked warm mix rubber powder modified asphalt according to claim 5, characterized in that: The pre-swelling agent is a mixture of environmentally friendly aromatic oil and naphthenic rubber oil in a mass ratio of 1:

2.

7. The semi-crosslinked warm mix rubber powder modified asphalt according to claim 1, characterized in that: The silane coupling agent is selected from any one of KH-500, KH-550 and KH-570.

8. The semi-crosslinked warm mix rubber powder modified asphalt according to claim 1, characterized in that: The asphalt is 70# base asphalt.

9. The semi-crosslinked warm mix rubber powder modified asphalt according to claim 1, characterized in that: The particle size of the waste rubber powder is 0.125 mm to 0.85 mm, and the particle size of the waste rubber powder is less than 0.425 mm, accounting for 60% to 70%.

10. The semi-crosslinked warm mix rubber powder modified asphalt according to claim 1, characterized in that: The anti-stripping agent is selected from any one of Zycosoil nano anti-stripping agent, monododecyl phosphate and phosphoglyceride; and / or; The dispersant is selected from any one of octavinyl cage-shaped polysilsesquioxide, polyethylene and graphene.

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