Modified asphalt and preparation method thereof

Abstract

The invention relates to the technical field of road engineering materials, in particular to modified asphalt and a preparation method thereof. According to the specific technical scheme, the modified asphalt is characterized by comprising the following components in parts by weight: 55-70 parts of asphalt, 30-40 parts of a wax-active rubber powder composite modifier, 0.5-1 part of a dispersing agent and 2-4 parts of modified oil. The waste tires can be effectively utilized, the mixing amount of the rubber powder in the asphalt is increased, the construction workability of the rubber asphalt is effectively improved, and the dual purposes of high utilization rate of the rubber particles and improvement of the asphalt performance are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of road engineering materials, and in particular to modified asphalt and a preparation method thereof. Background Art

[0002] Modified asphalt is the most important road material for highway construction and maintenance, but it has the problems of high price and large consumption of non-renewable resources. Therefore, there is an urgent need for new green and energy-saving asphalt pavement materials. Rubber asphalt is a recognized green and low-energy road paving material, which can achieve the high-value utilization of waste tire rubber powder and energy conservation and emission reduction.

[0003] High-volume rubber asphalt has excellent high-temperature rutting resistance, low-temperature cracking resistance, water stability and fatigue life, and has greater room for development. High-volume rubber asphalt generally refers to modified asphalt with a rubber modifier content of more than 30%. At present, the rubber powder content of road rubber asphalt is generally 15-20%, and there are large differences between waste rubber powder and asphalt in chemical structure, density, viscosity, molecular weight, etc., resulting in poor storage stability of rubber asphalt, easy segregation and stratification, poor construction and workability, especially high-volume rubber asphalt has higher viscosity and worse construction and workability, resulting in the application scale of rubber asphalt far less than SBS modified asphalt. Therefore, it is urgent to develop a rubber powder modified asphalt and its preparation method that can effectively increase the amount of rubber particles and improve the workability of rubber asphalt, so as to improve the application of waste tires in pavement engineering. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a modified asphalt and a preparation method thereof, which can effectively utilize waste tires, increase the amount of rubber powder in asphalt, effectively improve the construction and workability of rubber asphalt, and achieve the dual goals of high utilization rate of rubber particles and improved asphalt performance.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0006] The invention discloses a modified asphalt, which comprises the following components by weight: 55-70 parts of asphalt, 30-40 parts of wax-active rubber powder composite modifier, 0.5-1 part of dispersant and 2-4 parts of modified oil.

[0007] Preferably, in parts by weight: the wax-active rubber powder composite modifier includes the following components: 65-85 parts of rubber powder, 5-10 parts of wax type modifier, 3-15 parts of aromatic hydrocarbon-rich component, 1-12 parts of resin, and 1-15 parts of plasticizer.

[0008] Preferably, the aromatic-rich component includes one or a mixture of aromatic oil, pine tar, and rubber oil, the resin includes one or more of polyethylene, phenolic resin, natural rosin, random polypropylene, and petroleum resin, and the plasticizer includes one or more of phthalates, polybenzoates, and benzoate plasticizers.

[0009] Preferably, the dispersant includes one or more of dodecylbenzenesulfonic acid, N,N-dimethylamide, alkyl pyrrolidone, and alkyl phenolic resin oligomer.

[0010] Preferably, the modified oil includes one or more of furfural extracted oil, phenol extracted oil, and methylpyrrolidone extracted oil.

[0011] Correspondingly, a method for preparing modified asphalt includes the following steps: heating the asphalt to a flowing state, after high-speed shearing, adding a wax-active rubber powder composite modifier, a dispersant, and a modified oil for high-speed shearing, and after completion, stirring for 1.5 hours to 2 hours to obtain the modified asphalt.

[0012] Preferably, the asphalt is sheared at 160°C to 190°C and 1000rpm to 2000rpm for 5 to 10 minutes; after adding the wax-active rubber powder composite modifier, dispersant and modified oil, it is sheared at 180°C to 210°C and 4000rpm to 5000rpm for 30 to 40 minutes.

[0013] Preferably, the preparation process of the wax-active rubber powder composite modifier is:

[0014] (1) After the rubber powder is dried, the aromatic-rich component is added and stirred, and then the mixture is sealed and developed at 160° C. to 200° C. for 1 to 2 hours, and during the development process, the mixture is stirred for 5 to 8 minutes every 30 to 40 minutes until the development is completed;

[0015] (2) adding the resin and the plasticizer to the rubber powder obtained in step (1), stirring evenly and then letting it stand;

[0016] (3) The rubber powder obtained in step (2) and the wax type modifier are subjected to twin-screw extrusion to obtain a wax-active rubber powder composite modifier.

[0017] Preferably, the rubber powder is dried at 100° C. to 110° C. for 2.5 h to 3.5 h.

[0018] Preferably, in step (3), the extrusion temperature is 220° C. to 320° C., and the extrusion speed is 16 to 48 rpm.

[0019] The present invention has the following beneficial effects:

[0020] 1. In the wax-active rubber powder composite modifier formula and preparation process provided by the present invention, the compatibility between rubber powder particles and asphalt is improved by activating the waste rubber powder, and the agglomeration phenomenon of large-amount rubber powder in asphalt is improved, thereby improving the low-temperature crack resistance, high-temperature stability, aging resistance, durability and storage stability of the rubber powder modified asphalt.

[0021] 2. In the wax-active rubber powder composite modified asphalt formula and preparation process provided by the present invention, the wax type modifier (residue wax produced by Fischer-Tropsch synthesis, waste plastic cracking wax, etc.) is adsorbed on the surface of the active rubber powder through the extrusion action of the twin-screw, forming a dense lubricating film. When the wax-active rubber powder composite modifier is added to the asphalt, it serves as a transition layer between the active rubber powder and the asphalt, plays an excellent interfacial lubrication role, improves the viscosity-temperature characteristics of the rubber asphalt, greatly reduces the viscosity of the large-volume rubber asphalt, significantly improves the construction and workability, and makes the construction more convenient and efficient.

[0022] 3. The waste rubber powder of the present invention uses waste materials such as truck or automobile waste tires, which are widely available and inexpensive. It reduces the cost of use and solves the problem of handling a large number of waste tires, thus having good social and environmental benefits. DETAILED DESCRIPTION

[0023] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0025] 1. The present invention discloses a modified asphalt, which comprises the following components by weight: 55-70 parts of asphalt, 30-40 parts of wax-active rubber powder composite modifier, 0.5-1 part of dispersant, and 2-4 parts of modified oil. The dispersant comprises one or more of dodecylbenzenesulfonic acid (DBSA), N,N-dimethylamide, alkylpyrrolidone, and alkylphenol resin oligomer. The modified oil comprises one or more of furfural extracted oil, phenol extracted oil, and methylpyrrolidone extracted oil.

[0026] Furthermore, by weight: the wax-active rubber powder composite modifier includes the following components: 65-85 parts of rubber powder, 5-10 parts of wax type modifier, 3-15 parts of aromatic hydrocarbon-rich component, 1-12 parts of resin, and 1-15 parts of plasticizer. Among them, the rubber powder is waste rubber powder, which is mainly made from one or more of truck or car waste tires, waste tires, waste conveyor belts, rubber shoes, rubber tubes, and sealing rings, and the particle size range is 20-200 mesh. The wax type modifier is a mixture of one or more of the residue wax produced by Fischer-Tropsch synthesis, waste plastic cracking wax, and paraffin wax. These waxes have a good interface lubrication effect on rubber and can greatly enhance the workability of rubber asphalt.

[0027] Furthermore, the aromatic-rich component includes a mixture of one or more of aromatic oil, pine tar, and rubber oil. Aromatic-rich hydrocarbons have a good softening effect on rubber and increase the compatibility of rubber with asphalt; the resin includes one or more of polyethylene, phenolic resin, natural rosin, random polypropylene, and petroleum resin; the plasticizer includes one or more of phthalates, polybenzoates, and benzoate plasticizers.

[0028] 2. The present invention adopts a method of pre-swelling and twin-screw extrusion composite treatment to prepare modified asphalt, which specifically includes the following steps:

[0029] (1) Heat the asphalt to a flowing state, put it into a high-speed shearing machine, and shear it at 160°C to 190°C and 1000rpm to 2000rpm for 5 to 10 minutes;

[0030] (2) Add wax-active rubber powder composite modifier, dispersant and modified oil in step (1), and shear for 30 to 40 minutes at 180°C to 210°C and 4000 rpm to 5000 rpm. Then transfer the initially obtained wax-active rubber powder composite modified asphalt to a mixer and continue stirring for 1.5 hours to 2 hours to obtain the prepared wax-lubricated high-dosage active rubber powder composite modified asphalt that is easy to construct.

[0031] Furthermore, the preparation process of the wax-active rubber powder composite modifier is as follows:

[0032] (1) drying the rubber powder in an oven at 100°C to 110°C for 2.5h to 3.5h;

[0033] (2) placing the rubber powder of step (1) in a sealable container, adding the aromatic-rich component, stirring for 5 to 10 minutes, placing in an oven at 160° C. to 200° C. for 1 to 2 hours of sealed development; and stirring for 5 to 8 minutes every 30 to 40 minutes of development until the development is complete;

[0034] (3) adding the resin and the plasticizer to the rubber powder obtained in step (2), stirring at room temperature, stirring evenly and then letting it stand;

[0035] (3) adding the rubber powder and wax type modifier obtained in step (3) into a twin-screw extruder for twin-screw extrusion at an extrusion temperature of 220° C. to 320° C. and an extrusion speed of 16 to 48 rpm to obtain a wax-active rubber powder composite modifier.

[0036] The present invention will be further described below in conjunction with specific embodiments.

[0037] Example 1

[0038] 1. The wax-lubricated, high-content active rubber powder composite modified asphalt is easy to construct. The raw materials are calculated by weight: 67 parts of No. 70 heavy-duty road asphalt, 30 parts of wax-active rubber powder composite modifier, 1 part of dodecylbenzene sulfonic acid (DBSA), and 2 parts of furfural extracted oil.

[0039] The composition and weight fraction of each raw material of the wax-active rubber powder composite modifier are as follows: 85 parts of waste rubber powder, 5 parts of Fischer-Tropsch synthesis residue wax, 3 parts of aromatic oil, 3 parts of natural rosin, and 4 parts of benzene polyester.

[0040] 2. The preparation method of wax-active rubber powder composite modifier is as follows:

[0041] (1) placing the waste rubber powder in an oven at 105°C for 3 hours for drying; adding aromatic oil according to the ratio and stirring for 5 minutes, and then placing in an oven at 160°C for closed development for 1.5 hours, stirring for 5 minutes every 30 minutes of development until the development is complete;

[0042] (2) adding natural rosin and benzene polyester according to the ratio to the rubber powder obtained in step (1), stirring at room temperature for 30 minutes, and then standing at room temperature for 2 hours;

[0043] (3) adding the rubber powder obtained in step (2) and the Fischer-Tropsch slag wax into a twin-screw extruder, and extruding at an extrusion temperature of 320° C. and an extrusion speed of 16 rpm; co-extruding 4 times to obtain the wax-active rubber powder composite modifier.

[0044] 3. Construction and easy wax lubrication large amount of active rubber powder composite modified asphalt is prepared according to the following steps:

[0045] The heavy traffic road 70 asphalt is heated to a flowing state, put into a high-speed shearing machine, and sheared at 175°C and 1000rpm for 5 minutes. The wax-active rubber powder composite modifier, dodecylbenzenesulfonic acid (DBSA) and furfural extracted oil are added according to the ratio, and sheared at 180°C and 4000rpm for 30 minutes. Subsequently, the preliminary wax-rubber powder composite modified asphalt is transferred to a mixer and stirred for 1.5 hours to obtain the prepared wax-lubricated large-volume active rubber powder composite modified asphalt which is easy to construct and easy to use.

[0046] Example 2

[0047] 1. Easy to construct wax-lubricated, high-content active rubber powder composite modified asphalt. The raw materials are calculated by weight: 61.5 parts of No. 70 heavy-duty road asphalt, 35 parts of wax-active rubber powder composite modifier, 0.5 parts of alkyl pyrrolidone, and 3 parts of methyl pyrrolidone extracted oil.

[0048] The raw material composition and weight fraction ratio of the wax-active rubber powder composite modifier are as follows: 80 parts of waste rubber powder, 5 parts of waste plastic cracking wax, 6 parts of pine tar, 6 parts of polyethylene, and 3 parts of phthalate.

[0049] 2. The preparation method of wax-active rubber powder composite modifier is as follows:

[0050] (1) placing the waste rubber powder in a 100°C oven for 2.5 hours of drying; adding pine tar oil according to the ratio and stirring for 5 minutes, and then placing in a 170°C oven for closed development for 1.5 hours, stirring for 5 minutes every 30 minutes of development until the development is complete;

[0051] (2) adding polyethylene and phthalate according to the ratio to the rubber powder obtained in step (1), stirring at room temperature for 35 minutes, and then standing at room temperature for 2.5 hours;

[0052] (3) Add the rubber powder obtained in step (2) and the waste plastic cracking wax into a twin-screw extruder, and extrude at an extrusion temperature of 300° C. and an extrusion speed of 25 rpm; extrude 5 times to obtain the wax-active rubber powder composite modifier.

[0053] 3. Construction and easy wax lubrication large amount of active rubber powder composite modified asphalt is prepared according to the following steps:

[0054] The heavy traffic road 70 asphalt is heated to a flowing state, put into a high-speed shearing machine, and sheared at 180°C and 1500rpm for 5 minutes. Wax-active rubber powder composite modifier, alkyl pyrrolidone, and methyl pyrrolidone are added according to the ratio to extract the oil, and sheared at 200°C and 4000rpm for 30 minutes. Subsequently, the preliminary wax-rubber powder composite modified asphalt is transferred to a mixer and stirred for 1.5 hours to obtain the prepared wax-lubricated large-volume active rubber powder composite modified asphalt which is easy to construct and easy to use.

[0055] Example 3

[0056] 1. Easy to construct wax-lubricated, high-volume active rubber powder composite modified asphalt. The raw materials are calculated by weight: 55.5 parts of No. 70 heavy-duty road asphalt, 40 parts of wax-active rubber powder composite modifier, 0.5 parts of dodecylbenzene sulfonic acid (DBSA), and 4 parts of phenol extract oil.

[0057] The composition and weight fraction of each raw material of the wax-active rubber powder composite modifier are as follows: 80 parts of waste rubber powder, 10 parts of Fischer-Tropsch synthesis residue wax, 3 parts of rubber oil, 4 parts of petroleum resin, and 1 part of benzoate plasticizer.

[0058] 2. The preparation method of wax-active rubber powder composite modifier is as follows:

[0059] (1) placing the waste rubber powder in a 100°C oven for 2.7 hours of drying; adding rubber oil according to the ratio and stirring for 5 minutes, and then placing in a 180°C oven for closed development for 2 hours, stirring for 5 minutes every 30 minutes of development until the development is complete;

[0060] (2) adding petroleum resin and benzoate plasticizer to the rubber powder obtained in step (1) according to the ratio, stirring at room temperature for 40 minutes, and then standing at room temperature for 3 hours;

[0061] (3) adding the rubber powder obtained in step (2) and the Fischer-Tropsch slag wax into a twin-screw extruder, and extruding at an extrusion temperature of 250° C. and an extrusion speed of 30 rpm; co-extruding for 5 times to obtain the wax-active rubber powder composite modifier.

[0062] 3. Construction and easy wax lubrication large amount of active rubber powder composite modified asphalt is prepared according to the following steps:

[0063] The heavy traffic road 70 asphalt is heated to a flowing state, put into a high-speed shearing machine, and sheared at 190°C and 2000rpm for 10 minutes. The wax-active rubber powder composite modifier, dodecylbenzenesulfonic acid (DBSA) and phenol extract oil are added according to the ratio, and sheared at 210°C and 5000rpm for 40 minutes. Subsequently, the preliminary wax-rubber powder composite modified asphalt is transferred to a mixer and stirred for 2 hours to obtain the prepared wax-lubricated large-volume active rubber powder composite modified asphalt which is easy to construct and process.

[0064] Comparative Example 1

[0065] Referring to Example 1, the only difference from Example 1 is that the weight fraction ratio of each raw material of the wax-active rubber powder composite modifier is different, namely 70 parts of waste rubber powder, 0 parts of Fischer-Tropsch synthesis slag wax, 15 parts of aromatic oil, 10 parts of natural rosin, and 5 parts of benzene polyester.

[0066] Comparative Example 2

[0067] Referring to Example 1, the raw materials are calculated by weight: 67 parts of No. 70 heavy traffic road asphalt, 30 parts of wax-active rubber powder composite modifier, 1 part of dodecylbenzene sulfonic acid (DBSA), and 2 parts of furfural extracted oil.

[0068] The composition and weight fraction of each raw material of the wax-active rubber powder composite modifier are as follows: 85 parts of waste rubber powder, 5 parts of commercially available wax additives, 3 parts of aromatic oil, 3 parts of natural rosin, and 4 parts of benzene polyester.

[0069] The preparation method of the wax-active rubber powder composite modifier is as follows:

[0070] (1) placing the waste rubber powder in an oven at 120° C. for 3 h for drying; adding aromatic oil according to the ratio and stirring for 5 min, and then placing in an oven at 170° C. for closed development for 1.5 h, stirring for 5 min every 30 min of development until the development is complete;

[0071] (2) adding natural rosin and benzene polyester according to the ratio to the rubber powder obtained in step (1), stirring at room temperature for 30 minutes, and then standing at room temperature for 2 hours;

[0072] (3) Add the rubber powder obtained in step (2) and a commercially available wax additive into a twin-screw extruder, and extrude at an extrusion temperature of 350° C. and an extrusion speed of 16 rpm; extrude four times to obtain the wax-active rubber powder composite modifier.

[0073] The preparation process of rubber powder modified asphalt is as follows: heat the No. 70 asphalt for heavy traffic road to a flowing state, put it into a high-speed shearing machine, shear it at 175°C and 1000rpm for 5 minutes, add wax-active rubber powder composite modifier, dodecylbenzene sulfonic acid (DBSA), and furfural extracted oil according to the ratio, shear it at 180°C and 4000rpm for 30 minutes, and then transfer the preliminary rubber powder modified asphalt to a mixer and continue stirring for 1.5 hours to obtain the prepared rubber powder modified asphalt.

[0074] Comparative Example 3

[0075] Referring to Example 1, the raw materials are calculated by weight: 67 parts of No. 70 heavy traffic road asphalt, 30 parts of wax-active rubber powder composite modifier, 1 part of dodecylbenzene sulfonic acid (DBSA), and 2 parts of furfural extracted oil.

[0076] The composition and weight fraction of each raw material of the wax-active rubber powder composite modifier are as follows: 80 parts of waste rubber powder, 10 parts of paraffin wax, 3 parts of aromatic oil, 3 parts of natural rosin, and 4 parts of benzene polyester.

[0077] The preparation method of the wax-active rubber powder composite modifier is as follows:

[0078] (1) placing the waste rubber powder in an oven at 105°C for 3 hours for drying; adding aromatic oil according to the ratio and stirring for 5 minutes, and then placing in an oven at 160°C for closed development for 1.5 hours, stirring for 5 minutes every 30 minutes of development until the development is complete;

[0079] (2) adding natural rosin and benzene polyester according to the ratio to the rubber powder obtained in step (1), stirring at room temperature for 30 minutes, and then standing at room temperature for 2 hours;

[0080] (3) adding the rubber powder and paraffin obtained in step (2) into a twin-screw extruder, and extruding at an extrusion temperature of 320° C. and an extrusion speed of 16 rpm; co-extruding 4 times to obtain the wax-active rubber powder composite modifier.

[0081] The rubber powder modified asphalt is prepared according to the following steps: the heavy traffic road 70 asphalt is heated to a flowing state, put into a high-speed shearing machine, and sheared at 145°C and 1000rpm for 5 minutes, and the wax-active rubber powder composite modifier, dodecylbenzenesulfonic acid (DBSA), and furfural extracted oil are added according to the ratio, and sheared at 180°C and 3000rpm for 30 minutes. Then, the preliminary wax-rubber powder composite modified asphalt is transferred to a mixer and continued to be stirred for 1 hour to obtain the prepared active rubber powder composite modified asphalt.

[0082] The test results of the modified asphalt prepared in each embodiment and comparative example are shown in Table 1 below.

[0083] Table 1 Test results of indicators of Examples 1-3 and Comparative Examples 1-3

[0084]

[0085] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A modified asphalt, characterized in that: The composition comprises the following components by weight: 55-70 parts of asphalt, 30-40 parts of wax-active rubber powder composite modifier, 0.5-1 part of dispersant and 2-4 parts of modified oil.

2. A modified asphalt according to claim 1, characterized in that: In terms of weight: the wax-active rubber powder composite modifier includes the following components: 65-85 parts of rubber powder, 5-10 parts of wax type modifier, 3-15 parts of aromatic hydrocarbon-rich component, 1-12 parts of resin, and 1-15 parts of plasticizer.

3. A modified asphalt according to claim 2, characterized in that: The aromatic-rich component includes one or a mixture of aromatic oil, pine tar, and rubber oil; the resin includes one or more of polyethylene, phenolic resin, natural rosin, random polypropylene, and petroleum resin; and the plasticizer includes one or more of phthalate esters, polybenzoate esters, and benzoate plasticizers.

4. The modified asphalt according to claim 1, characterized in that: The dispersant includes one or more of dodecylbenzenesulfonic acid, N,N-dimethylamide, alkyl pyrrolidone, and alkyl phenolic resin oligomer.

5. A modified asphalt according to claim 1 or 4, characterized in that: The modified oil includes one or more of furfural extracted oil, phenol extracted oil and methyl pyrrolidone extracted oil.

6. A method for preparing the modified asphalt according to any one of claims 1 to 4, characterized in that: The following steps are involved: The asphalt is heated to a flowing state, and after high-speed shearing, a wax-active rubber powder composite modifier, a dispersant, and a modified oil are added for high-speed shearing. After completion, the modified asphalt is obtained by stirring for 1.5 hours to 2 hours.

7. The preparation method according to claim 6, characterized in that: The asphalt is sheared at 160°C to 190°C and 1000rpm to 2000rpm for 5 to 10 minutes; after adding a wax-active rubber powder composite modifier, a dispersant and modified oil, the asphalt is sheared at 180°C to 210°C and 4000rpm to 5000rpm for 30 to 40 minutes.

8. The preparation method according to claim 6, characterized in that: The preparation process of the wax-active rubber powder composite modifier is as follows: (1) drying the rubber powder, adding the aromatic hydrocarbon-rich component and stirring, and then developing it in a closed environment at 160° C. to 200° C. for 1 to 2 hours, and during the development process, stirring it for 5 to 8 minutes every 30 to 40 minutes until the development is completed; (2) adding the resin and the plasticizer to the rubber powder obtained in step (1), stirring evenly and then letting it stand; (3) The rubber powder obtained in step (2) and the wax type modifier are subjected to twin-screw extrusion to obtain a wax-active rubber powder composite modifier.

9. The preparation method according to claim 8, characterized in that: The rubber powder is dried at 100° C. to 110° C. for 2.5 h to 3.5 h.

10. The preparation method according to claim 8, characterized in that: In step (3), the extrusion temperature is 220° C. to 320° C., and the extrusion speed is 16 to 48 rpm.

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