A kind of fatigue and rutting resistance modifier and preparation method thereof

Abstract

The present application relates to the field of asphalt road materials, and specifically discloses a fatigue-resistant and anti-rutting modifier and a preparation method thereof; a fatigue-resistant and anti-rutting modifier; comprising the following raw materials in parts by weight: 40-50 parts of sulfur, 3-8 parts of hard asphalt, 8-15 parts of ethylene-vinyl acetate copolymer, 20-40 parts of low-density polyethylene, 5-8 parts of polyoctene, 20-30 parts of styrene-butadiene rubber, and 3-5 parts of polyphosphoric acid; in the modifier of the present application, ethylene-vinyl acetate copolymer is used to enhance the low-temperature toughness of the asphalt mixture and reduce the phenomenon of low-temperature cracking, polyoctene is used to react with sulfur to enhance the viscosity between asphalt molecules and the modifier, and polyphosphoric acid is used to enhance the compatibility of reinforcing components such as styrene-butadiene rubber and low-density polyethylene with asphalt molecules, thereby improving the compactness of the asphalt road structure and improving the anti-rutting performance and fatigue resistance of the asphalt road.

Description

Technical Field

[0001] The present application relates to the field of asphalt road materials, and in particular to a fatigue and rutting resistance modifier and a preparation method thereof. Background Art

[0002] In current road construction, asphalt concrete is a widely used pavement material. However, traditional asphalt materials are prone to softening and deformation in high temperature environments, resulting in rutting on the road surface. They are prone to fatigue damage under long-term repeated loads, seriously affecting the service quality and life of the road.

[0003] In the existing technology, the commonly used improvement method is to add sulfur to asphalt, using the high modulus characteristics of sulfur to improve the rigidity and stability of asphalt. However, sulfur can only improve the high-temperature performance of asphalt mixtures. In low-temperature environments, brittle cracking, cracking, and loosening may occur, freeze-thaw cycles, asphalt aging, and thus cause road fatigue damage and loss of service function. Summary of the invention

[0004] In order to improve the fatigue resistance, rutting resistance and low temperature performance of asphalt roads, the present application provides a fatigue resistance and rutting resistance modifier and a preparation method thereof.

[0005] In the first aspect, the present application provides a fatigue and rutting resistance modifier, which adopts the following technical solution: A fatigue and rutting resistance modifier comprises the following raw materials in parts by weight: 40-50 parts of sulfur, 3-8 parts of hard asphalt, 8-15 parts of ethylene-vinyl acetate copolymer, 20-40 parts of low-density polyethylene, 5-8 parts of polyoctene, 20-30 parts of styrene-butadiene rubber and 3-5 parts of polyphosphoric acid.

[0006] By adopting the above technical solution, adding an appropriate amount of hard asphalt to the modifier system can be added to the asphalt mixture later to enhance the compatibility of the modifier particles with the asphalt and promote the uniform dispersion of the modifier in the asphalt mixture system. Sulfur improves the high-temperature performance of the asphalt mixture, and polyoctenes can undergo a cross-linking reaction with sulfur to form a network structure in the asphalt mixture system, which can enhance the viscosity between the modifier and the asphalt, thereby improving the low-temperature crack resistance of the asphalt road and reducing the segregation of the asphalt molecules and the modifier components. The use of ethylene-vinyl acetate copolymer can bond the components in the modifier system together, improve the flexibility of the asphalt mixture, and reduce the phenomenon of crushing and dust during processing and use.

[0007] The use of styrene-butadiene rubber can improve the flexibility and crack resistance of asphalt pavement at low temperatures, reduce the phenomenon of cracking and deformation of asphalt pavement at low temperatures, and polyphosphoric acid can improve the rutting resistance of asphalt pavement at high temperatures. Polyphosphoric acid can interact with asphaltene in asphalt, which can make the combination between modifier molecules and asphalt mixture molecules tighter and more stable, thereby enhancing the interaction between styrene-butadiene rubber, low-density polyethylene and asphalt molecules, improving the density of asphalt pavement structure, enhancing the resistance of asphalt pavement to external loads, and improving the deformation resistance and fatigue resistance of asphalt pavement under external loads.

[0008] After the chemical reaction between low-density polyethylene and asphalt molecules, a strong interface layer can be formed, which can withstand greater shear force, reduce the fatigue energy consumption of asphalt roads, increase the viscoelasticity of asphalt, and improve the high-temperature rutting resistance and fatigue resistance of asphalt roads.

[0009] Preferably, the hard asphalt is at least one of petroleum asphalt, natural asphalt and coal asphalt.

[0010] Preferably, the vinyl acetate content in the ethylene-vinyl acetate copolymer is 40wt%-70wt%.

[0011] Preferably, the low-density polyethylene is grafted with glycidyl methacrylate and styrene, and the grafting method comprises the following specific steps: The low-density polyethylene is mixed evenly with glycidyl methacrylate, styrene and an initiator, and heated to melt for reaction, and a low-density polyethylene graft copolymer is obtained after the reaction.

[0012] By adopting the above technical scheme, the glycidyl methacrylate molecule contains carbon-carbon double bonds and epoxy groups. Through grafting, the epoxy functional groups on the side chains of low-density polyethylene can be promoted to undergo a ring-opening reaction with carboxyl groups, acid anhydride groups and other groups in asphaltene in the asphalt system to form a cross-linked interconducting network structure, thereby increasing the compatibility of low-density polyethylene with asphalt, and being able to improve the high-temperature rutting resistance, fatigue resistance and low-temperature cracking resistance of asphalt roads.

[0013] The polystyrene chain segments formed by grafting styrene with low-density polyethylene can enhance the rigidity and thermal stability of low-density polyethylene. At the same time, the polystyrene chain segments have good compatibility with the asphalt matrix components, improve the interface bonding between the modifier and the asphalt matrix, and improve the fatigue resistance and rutting resistance of the asphalt road.

[0014] Preferably, the reaction temperature is 180-190°C.

[0015] Preferably, the mass ratio of the low-density polyethylene to glycidyl methacrylate, styrene and initiator is 1:(0.3-0.5):(0.1-0.3):(0.03-0.05).

[0016] In a second aspect, the present application provides a method for preparing a fatigue and anti-rutting modifier, using the following technical solution: A method for preparing a fatigue and rutting resistance modifier comprises the following specific steps: Add polyoctenes and sulfur to the hard asphalt, mix and stir evenly, then add ethylene-vinyl acetate copolymer, low-density polyethylene and styrene-butadiene rubber, mix and stir evenly, finally add polyphosphoric acid, mix, heat and melt, extrude and granulate to obtain the fatigue and rutting resistance modifier.

[0017] By adopting the above technical solution, polyoctenes and sulfur are first added to the hard asphalt, which can not only promote the pre-melting of the hard asphalt and make the hard asphalt more compatible with other components, but also promote the cross-linking reaction of polyoctenes and sulfur, thereby improving the high-temperature rutting resistance, fatigue resistance and low-temperature cracking resistance of the asphalt road. Finally, adding polyphosphoric acid can promote the uniform dispersion of each component in the modifier system, and improve the uniform dispersion of the modifier in the asphalt matrix, thereby improving the anti-rutting performance and low-temperature cracking resistance of the asphalt road.

[0018] Preferably, the melting temperature is 120-130°C.

[0019] In summary, this application has the following beneficial effects: 1. Since the present application adopts polyoctenes and sulfur to cross-link and form a network structure, the high-temperature rutting resistance, fatigue resistance and low-temperature cracking resistance of the asphalt road are improved. The use of ethylene-vinyl acetate copolymer can bond the components in the modifier system together, improve the binding force between the modifier and asphalt, and reduce the phenomenon of segregation and dust between the asphalt matrix and the modifier during use. The use of styrene-butadiene rubber improves the low-temperature flexibility and cracking resistance of the asphalt pavement, and the use of low-density polyethylene improves the high-temperature rutting resistance and fatigue resistance of the asphalt road. At the same time, polyphosphoric acid is used to improve the binding force between styrene-butadiene rubber, low-density polyethylene and asphalt molecules, and improves the deformation resistance and fatigue resistance of the asphalt road.

[0020] 2. In this application, glycidyl methacrylate and styrene are used to graft-modify low-density polyethylene, so that the side chains of low-density polyethylene have active functional groups, which can undergo ring-opening reactions with carboxyl groups, acid anhydrides and other groups in asphaltene in the asphalt system to form a cross-linked interconductive polymer network, increase the compatibility of low-density polyethylene and asphalt, and improve the high-temperature rutting resistance, fatigue resistance and low-temperature cracking resistance of asphalt roads. DETAILED DESCRIPTION

[0021] The present application is further described in detail below with reference to the embodiments.

[0022] All raw materials in the examples are commercially available. Example

[0023] Example 1 The present embodiment provides a fatigue and rutting resistance modifier, comprising the following raw materials in parts by weight: 45 kg of sulfur, 5 kg of hard asphalt, 12 kg of ethylene-vinyl acetate copolymer, 30 kg of low-density polyethylene, 7 kg of polyoctene, 25 kg of styrene-butadiene rubber, and 4 kg of polyphosphoric acid; wherein the content of phosphorus pentoxide in the polyphosphoric acid is 75%, and the density of the low-density polyethylene is 0.921 g / cm 3 (15°C), melt index 1.83g / 10min, vinyl acetate content in ethylene-vinyl acetate copolymer is 55wt%, CAS No. of styrene-butadiene rubber is 9003-55-8, polyoctene is poly-1-octene, and hard asphalt is petroleum asphalt.

[0024] The preparation method of the fatigue and rutting resistance modifier comprises the following specific steps: Add polyoctenes and sulfur to the hard asphalt and mix them. Stir at a speed of 1300 rpm for 30 minutes. Then add ethylene-vinyl acetate copolymer, low-density polyethylene and styrene-butadiene rubber and mix them evenly. Finally, add polyphosphoric acid and mix them. Heat to 125°C to melt, extrude and granulate to obtain a fatigue and rutting resistance modifier.

[0025] Example 2 The difference between Example 2 and Example 1 is that the amount of sulfur used in the raw materials of the fatigue and rutting resistance modifier is 40 kg, the amount of hard asphalt used is 3 kg, the amount of ethylene-vinyl acetate copolymer used is 8 kg, the amount of low-density polyethylene used is 20 kg, the amount of polyoctene used is 8 kg, the amount of styrene-butadiene rubber used is 20 kg, and the amount of polyphosphoric acid used is 3 kg.

[0026] Example 3 The difference between Example 3 and Example 1 is that the amount of sulfur used in the raw materials of the fatigue and rutting resistance modifier is 50 kg, the amount of hard asphalt used is 8 kg, the amount of ethylene-vinyl acetate copolymer used is 15 kg, the amount of low-density polyethylene used is 40 kg, the amount of polyoctene used is 5 kg, the amount of styrene-butadiene rubber used is 30 kg, and the amount of polyphosphoric acid used is 5 kg.

[0027] Example 4 The difference between Example 4 and Example 1 is that the content of vinyl acetate in the ethylene-vinyl acetate copolymer in the raw material of the fatigue and rutting resistance modifier is 40 wt%.

[0028] Example 5 The difference between Example 5 and Example 1 is that the content of vinyl acetate in the ethylene-vinyl acetate copolymer in the raw material of the fatigue resistance and rutting resistance modifier is 70 wt %.

[0029] Example 6 The difference between Example 6 and Example 1 is that the low-density polyethylene in the raw material of the fatigue and rutting resistance modifier is grafted with glycidyl methacrylate and styrene.

[0030] The preparation method of the fatigue and rutting resistance modifier comprises the following specific steps: S1: Mix low-density polyethylene, glycidyl methacrylate, styrene and initiator evenly. The initiator is dibenzoyl peroxide. The mass ratio of low-density polyethylene to glycidyl methacrylate, styrene and initiator is 1:0.4:0.2:0.04. Stir at a speed of 100 r / min for 0.5 h, heat to 185°C for melting reaction for 15 min, and obtain a low-density polyethylene graft copolymer after the reaction.

[0031] S2: Add polyoctenes and sulfur to hard asphalt and mix them. Stir at a speed of 1300 rpm for 30 minutes. Then add ethylene-vinyl acetate copolymer, low-density polyethylene graft copolymer and styrene-butadiene rubber and mix them evenly. Finally, add polyphosphoric acid and mix. Heat to 125°C to melt, extrude and granulate to obtain a fatigue and rutting resistance modifier.

[0032] Example 7 The difference between Example 7 and Example 6 is that the mass ratio of low-density polyethylene to glycidyl methacrylate, styrene and initiator in the raw material of the fatigue and rutting resistance modifier is 1:0.3:0.3:0.03.

[0033] Example 8 The difference between Example 8 and Example 6 is that the mass ratio of low-density polyethylene to glycidyl methacrylate, styrene and initiator in the raw material of the fatigue and rutting resistance modifier is 1:0.5:0.1:0.05.

[0034] Example 9 The difference between Example 9 and Example 6 is that styrene is not used in the raw material of the fatigue and rutting resistance modifier.

[0035] The preparation method of the fatigue and rutting resistance modifier comprises the following specific steps: S1: low-density polyethylene, glycidyl methacrylate and initiator are mixed evenly, the initiator is dibenzoyl peroxide, the mass ratio of low-density polyethylene to glycidyl methacrylate and initiator is 1:0.4:0.04, stirred at a speed of 100 r / min for 0.5 h, heated to 185°C for melting reaction for 15 min, and a low-density polyethylene graft copolymer is obtained after the reaction.

[0036] S2: Add polyoctenes and sulfur to hard asphalt and mix them. Stir at a speed of 1300 rpm for 30 minutes. Then add ethylene-vinyl acetate copolymer, low-density polyethylene graft copolymer and styrene-butadiene rubber and mix them evenly. Finally, add polyphosphoric acid and mix. Heat to 125°C to melt, extrude and granulate to obtain a fatigue and rutting resistance modifier.

[0037] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that polyoctenes are not used in the raw material of the fatigue and rutting resistance modifier.

[0038] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that polyphosphoric acid is not used in the raw material of the fatigue and rutting resistance modifier.

[0039] Performance testing According to the fatigue and rutting resistance modifier provided in Examples 1-9 and Comparative Examples 1-2 of the present application, after the asphalt mixture is heated, the fatigue and rutting resistance modifier prepared in the present application is added for mixing, and then the following performance tests are performed. The specific test results are shown in Table 1.

[0040] Detection Methods According to the asphalt mixture specimen preparation method - compaction method (T0702-2011) in JTG E20-2011 "Highway Engineering Asphalt and Asphalt Mixture Test Procedure", AC-20 type gradation and 4.2% asphalt-stone ratio (4.0% asphalt content, 0.2% modifier content) were selected to simulate on-site production of asphalt concrete precast parts, and the precast parts were subjected to rutting test according to the standard of T0719-2011 "Asphalt Mixture Rutting Test", and the precast parts were subjected to freeze-thaw splitting test according to the standard of T0729-2011 "Asphalt Mixture Freeze-thaw Split Test". According to the standard of T0728 "Asphalt Mixture Bending Creep Test", the precast parts were subjected to low-temperature bending test.

[0041] Table 1: Performance test results data table Table 1: Performance test results data table It can be seen from the performance test results that the fatigue and anti-rutting modifier prepared by the present application has good anti-rutting performance, fatigue resistance and low-temperature crack resistance after being put into asphalt mixture. By comparing Comparative Examples 1-2 with Example 1, it can be seen that the anti-rutting performance and freeze-thaw splitting strength of the asphalt mixture in Comparative Example 1 without using polyoctenes are significantly reduced, and the low-temperature performance of the asphalt mixture in Comparative Example 1 is also reduced. It further illustrates that polyoctenes can undergo cross-linking reaction with sulfur to form a network structure in the asphalt mixture system, thereby improving the low-temperature performance and anti-rutting performance of the asphalt mixture. Comparative Example 2 does not use polyphosphoric acid. It can be seen from the performance test results that the anti-rutting performance of the asphalt mixture of Comparative Example 2 is significantly reduced, further illustrating that polyphosphoric acid can interact with asphaltene in asphalt, thereby promoting the compatibility of reinforcing components such as styrene-butadiene rubber and low-density polyethylene with asphalt molecules, improving the overall density of the asphalt mixture, and improving the deformation resistance and fatigue resistance of the asphalt road under external loads.

[0042] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. A fatigue and rutting resistance modifier, characterized in that: The invention comprises the following raw materials in parts by weight: 40-50 parts of sulfur, 3-8 parts of hard asphalt, 8-15 parts of ethylene-vinyl acetate copolymer, 20-40 parts of low-density polyethylene, 5-8 parts of polyoctene, 20-30 parts of styrene-butadiene rubber and 3-5 parts of polyphosphoric acid.

2. The fatigue and rutting resistance modifier according to claim 1, characterized in that: The hard asphalt is at least one of petroleum asphalt, natural asphalt and coal asphalt.

3. The fatigue and rutting resistance modifier according to claim 1, characterized in that: The vinyl acetate content in the ethylene-vinyl acetate copolymer is 40wt%-70wt%.

4. The fatigue and rutting resistance modifier according to claim 1, characterized in that: The low-density polyethylene is grafted with glycidyl methacrylate and styrene, and the grafting method comprises the following specific steps: The low-density polyethylene is mixed evenly with glycidyl methacrylate, styrene and an initiator, and heated to melt for reaction, and a low-density polyethylene graft copolymer is obtained after the reaction.

5. The anti-fatigue and anti-rutting modifier according to claim 4, characterized in that: The reaction temperature is 180-190°C.

6. The fatigue and rutting resistance modifier according to claim 4, characterized in that: The mass ratio of the low-density polyethylene to glycidyl methacrylate, styrene and initiator is 1: (0.3-0.5): (0.1-0.3): (0.03-0.05).

7. A method for preparing the fatigue and rutting resistance modifier according to any one of claims 1 to 6, characterized in that: The specific steps include: Add polyoctenes and sulfur to the hard asphalt, mix and stir evenly, then add ethylene-vinyl acetate copolymer, low-density polyethylene and styrene-butadiene rubber, mix and stir evenly, finally add polyphosphoric acid, mix, heat and melt, extrude and granulate to obtain the fatigue and rutting resistance modifier.

8. The method for preparing the anti-fatigue and anti-rutting modifier according to claim 7, characterized in that: The melting temperature is 120-130°C.

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