Rubber modified asphalt mixture and preparation method thereof

Abstract

The invention discloses a rubber modified asphalt mixture and a preparation method thereof. According to the invention, the emulsifier is used for adjusting the surface activity of the asphalt, the modifier is used for improving the performance of the asphalt, and finally, an additional additive is used for adjusting the weather resistance of the mixture, so that the rubber modified asphalt mixture with excellent weather resistance and high pressure resistance is prepared.

Description

Technical Field

[0001] The invention relates to the technical field of road construction materials, and more specifically to a rubber modified asphalt mixture and a preparation method thereof. Background Art

[0002] With the rapid development of global infrastructure construction, road projects have higher and higher performance requirements for pavement materials. As one of the most widely used materials in road construction, the performance of asphalt mixture directly affects the service life and driving safety of the road. Although traditional asphalt mixture has good adhesion and stability, it is prone to deformation and cracking under harsh conditions such as high temperature, low temperature and heavy traffic, thus affecting the performance of the road.

[0003] In order to improve the performance of asphalt mixtures, researchers have developed a variety of modified asphalt technologies, such as SBS modified asphalt, rubber modified asphalt, etc. These modified asphalts improve the high temperature stability and low temperature crack resistance of asphalt by adding polymers, rubber and other materials. Although the existing modified asphalt mixture technology has improved the performance of pavement materials to a certain extent, there are still problems. Under extreme climatic conditions, the performance improvement of existing modified asphalt mixtures is limited, and under long-term heavy-load traffic, the durability of modified asphalt mixtures still needs to be improved.

[0004] Providing a rubber-modified asphalt mixture with good stability, compression resistance and durability under extreme climatic conditions is the focus of the present invention. Summary of the invention

[0005] 1. To solve the above technical problems, the technical solution provided by the present invention includes the following contents:

[0006] (1) Heat 100 parts of base asphalt at 130-140°C until it becomes fluid, add 1-2 parts of emulsifier at 60-70°C and 50-60 parts of distilled water at 60-70°C while stirring, and keep stirring for 30 minutes after the addition is complete;

[0007] (2) The emulsified asphalt is heated to 150°C, and 20-30 parts of a modifier at 135°C is added while stirring. After the addition is complete, stirring is continued for 30 minutes to obtain a mixture A.

[0008] (3) Mixture A was transferred to a shearing device and sheared at 180°C for 45 min. After the shearing, it was placed at 175°C for 1 h to obtain modified asphalt.

[0009] (4) 120-160 parts of coarse aggregate with a particle size of 2.36-16 mm, 30-60 parts of fine aggregate with a particle size of 0.075-2.36 mm, 10-30 parts of filler with a particle size less than 0.075 mm, and 0.3-0.6 parts of additives are stirred and mixed at 135°C-165°C to obtain aggregate;

[0010] (5) Take the modified asphalt and aggregate in a mass ratio of 10-13:180-195, stir and mix at 140°C-160°C, and cure at 170°C-190°C to obtain a rubber modified asphalt mixture.

[0011] 2. Furthermore, the emulsifier is 1-benzyloxy-3-isopropoxy-2-propanol.

[0012] 3. Furthermore, the modifier is a mixture of 50% vulcanized styrene butadiene rubber and 50% rubber powder.

[0013] 4. Furthermore, the additive is polyamide polyurea formaldehyde resin.

[0014] The beneficial effects of the present invention are:

[0015] (1) The present invention utilizes emulsifiers and modifiers to modify and optimize the base asphalt, and uses additives during the aggregate mixing process to improve the uniformity of aggregate particles. After the final stirring, the various reagents work together to comprehensively improve the stability, weather resistance, and durability of the asphalt mixture.

[0016] (2) In the present invention, rubber is added to the asphalt for modification. However, the compatibility between the base asphalt and the modifier is insufficient, and rubber precipitation is likely to occur. Therefore, the base asphalt needs to be emulsified with an emulsifier before modification. The present invention selects 1-benzyloxy-3-isopropoxy-2-propanol as the emulsifier. The emulsifier has good surface activity and can well promote the compatibility between rubber and asphalt. 1-benzyloxy-3-isopropoxy-2-propanol can form a cavity structure on the surface of different phases by hydrogen bonding. Different substances in the system can be on both sides of the cavity structure, thereby improving the compatibility between different particles. In addition, the emulsifier can assist in film formation to increase the continuous phase in the asphalt mixture and make it more dense, thereby increasing the hardness of the asphalt mixture and improving the pressure resistance.

[0017] (3) Common rubber-modified asphalt mixtures have limited modification effects on asphalt and are now unable to meet demand. Therefore, additional modifying materials are needed to be mixed with rubber powder to modify asphalt. Sulfurized styrene butadiene rubber has good mechanical and physical and chemical properties. It is added to asphalt as a partial modifier to avoid fluidity inhibition and improve aging resistance and high and low temperature resistance. After styrene butadiene rubber is mixed into asphalt and swells, it absorbs the light components in the asphalt and hardens. It can also form a miscible system with asphalt in a three-dimensional network structure, which can effectively improve the wear resistance and compression resistance of the asphalt mixture and improve the physical properties of the asphalt mixture.

[0018] (4) In order to comprehensively improve the properties of the mixture and compensate for the problem of stringent construction environment requirements caused by the introduction of hydrophilic groups in emulsifiers and modifiers, appropriate additives are added during the aggregate mixing process to modify the surface of the material, adjust the apparent density and water absorption rate of the aggregate to adjust the construction effect of the finished mixture under extreme conditions and the low-temperature compressive strength of the finished product.

[0019] (5) The present invention uses polyamide polyurea formaldehyde resin as an additive, which can form covalent bonds and ionic bonds with the hydrophilic components in the asphalt mixture to introduce hydrophobic effects therein. The polyamide polyurea formaldehyde resin can be cationic in this system and can form micro-flocculation with negatively charged substances after stirring, thereby improving the uniformity of particles in the asphalt mixture and improving its physical properties. It can also form cross-linking and curing with various components in the asphalt to further improve the pressure resistance and wear resistance of the mixture. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below with reference to the embodiments.

[0021] Unless otherwise specified, the raw materials in the examples of the present invention were obtained through conventional commercial channels.

[0022] Example 1

[0023] 1. Take vulcanized styrene-butadiene rubber and rubber powder in a mass ratio of 1:1, heat until they have fluidity, combine and stir to obtain a modifier;

[0024] 2. Heat 100 parts of base asphalt at 130-140°C to a fluid state, add 1.5 parts of 1-benzyloxy-3-isopropoxy-2-propanol at 60-70°C and 55 parts of distilled water at 60-70°C while stirring, and keep stirring for 30 minutes after the addition is completed;

[0025] 3. The emulsified asphalt is heated to 150°C, and 25 parts of the modifier at 135°C are added while stirring. After the addition is completed, stirring is continued for 30 minutes to obtain a mixture A;

[0026] 4. Mixture A was transferred to a shearing device and sheared at 180°C for 45 minutes. After the shearing, it was placed at 175°C for 1 hour to obtain modified asphalt;

[0027] 5. Take 140 parts of coarse aggregate with a particle size of 2.36-16 mm, 45 parts of fine aggregate with a particle size of 0.075-2.36 mm, 20 parts of filler with a particle size less than 0.075 mm, and 0.45 parts of polyamide polyurea formaldehyde resin, stir and mix at 135°C-165°C to obtain aggregate;

[0028] 6. Take the modified asphalt and aggregate mass ratio of 11.5:187.5, stir and mix at 140℃~160℃, and cure at 170℃~190℃ to obtain rubber modified asphalt mixture.

[0029] Example 2

[0030] 1. Take vulcanized styrene-butadiene rubber and rubber powder in a mass ratio of 1:1, heat until they have fluidity, combine and stir to obtain a modifier;

[0031] 2. Heat 100 parts of base asphalt at 130-140°C to a fluid state, add 2 parts of 1-benzyloxy-3-isopropoxy-2-propanol at 60-70°C and 55 parts of distilled water at 60-70°C while stirring, and keep stirring for 30 minutes after the addition is completed;

[0032] 3. The emulsified asphalt is heated to 150°C, and 20 parts of the modifier at 135°C are added while stirring. After the addition is completed, stirring is continued for 30 minutes to obtain a mixture A;

[0033] 4. Mixture A was transferred to a shearing device and sheared at 180°C for 45 minutes. After the shearing, it was placed at 175°C for 1 hour to obtain modified asphalt;

[0034] 5. Take 140 parts of coarse aggregate with a particle size of 2.36-16 mm, 45 parts of fine aggregate with a particle size of 0.075-2.36 mm, 20 parts of filler with a particle size less than 0.075 mm, and 0.3 parts of polyamide polyurea formaldehyde resin, stir and mix at 135°C-165°C to obtain aggregate;

[0035] 6. Take the modified asphalt and aggregate mass ratio of 11.5:187.5, stir and mix at 140℃~160℃, and cure at 170℃~190℃ to obtain rubber modified asphalt mixture.

[0036] Example 3

[0037] 1. Take vulcanized styrene-butadiene rubber and rubber powder in a mass ratio of 1:1, heat until they have fluidity, combine and stir to obtain a modifier;

[0038] 2. Heat 100 parts of base asphalt at 130-140°C until it is fluid, add 1 part of 1-benzyloxy-3-isopropoxy-2-propanol at 60-70°C and 55 parts of distilled water at 60-70°C while stirring, and keep stirring for 30 minutes after the addition is completed;

[0039] 3. The emulsified asphalt is heated to 150°C, and 30 parts of the modifier at 135°C are added while stirring. After the addition is completed, stirring is continued for 30 minutes to obtain a mixture A;

[0040] 4. Mixture A was transferred to a shearing device and sheared at 180°C for 45 minutes. After the shearing, it was transferred to 175°C for 1 hour to obtain modified asphalt;

[0041] 5. Take 140 parts of coarse aggregate with a particle size of 2.36-16 mm, 45 parts of fine aggregate with a particle size of 0.075-2.36 mm, 20 parts of filler with a particle size less than 0.075 mm, and 0.6 parts of polyamide polyurea formaldehyde resin, stir and mix at 135°C-165°C to obtain aggregate;

[0042] 6. Take the modified asphalt and aggregate mass ratio of 11.5:187.5, stir and mix at 140℃~160℃, and cure at 170℃~190℃ to obtain rubber modified asphalt mixture.

[0043] Comparative Example 1

[0044] The difference between this comparative example and Example 1 is that the 1-benzyloxy-3-isopropoxy-2-propanol in step 1 is dodecanol ester, and the rest of the implementation method is the same as Example 1.

[0045] Comparative Example 2

[0046] 1. Take vulcanized styrene-butadiene rubber and rubber powder in a mass ratio of 1:1, heat until they have fluidity, combine and stir to obtain a modifier;

[0047] 2. Heat 100 parts of base asphalt at 130-140°C to a fluid state, add 0.5 parts of 1-benzyloxy-3-isopropoxy-2-propanol at 60-70°C and 55 parts of distilled water at 60-70°C while stirring, and keep stirring for 30 minutes after the addition is completed;

[0048] 3. The emulsified asphalt is heated to 150°C, and 25 parts of the modifier at 135°C are added while stirring. After the addition is completed, stirring is continued for 30 minutes to obtain a mixture A;

[0049] 4. Mixture A was transferred to a shearing device and sheared at 180°C for 45 minutes. After the shearing, it was transferred to 175°C for 1 hour to obtain modified asphalt;

[0050] 5. Take 140 parts of coarse aggregate with a particle size of 2.36-16 mm, 45 parts of fine aggregate with a particle size of 0.075-2.36 mm, 20 parts of filler with a particle size less than 0.075 mm, and 0.45 parts of polyamide polyurea formaldehyde resin, stir and mix at 135°C-165°C to obtain aggregate;

[0051] 6. Take the modified asphalt and aggregate mass ratio of 11.5:187.5, stir and mix at 140℃~160℃, and cure at 170℃~190℃ to obtain rubber modified asphalt mixture.

[0052] Comparative Example 3

[0053] 1. Take vulcanized styrene-butadiene rubber and rubber powder in a mass ratio of 1:1, heat until they have fluidity, combine and stir to obtain a modifier;

[0054] 2. Heat 100 parts of base asphalt at 130-140°C to a fluid state, add 2.5 parts of 1-benzyloxy-3-isopropoxy-2-propanol at 60-70°C and 55 parts of distilled water at 60-70°C while stirring, and keep stirring for 30 minutes after the addition is completed;

[0055] 3. The emulsified asphalt is heated to 150°C, and 25 parts of the modifier at 135°C are added while stirring. After the addition is completed, stirring is continued for 30 minutes to obtain a mixture A;

[0056] 4. Mixture A was transferred to a shearing device and sheared at 180°C for 45 minutes. After the shearing, it was placed at 175°C for 1 hour to obtain modified asphalt;

[0057] 5. Take 140 parts of coarse aggregate with a particle size of 2.36-16 mm, 45 parts of fine aggregate with a particle size of 0.075-2.36 mm, 20 parts of filler with a particle size less than 0.075 mm, and 0.45 parts of polyamide polyurea formaldehyde resin, stir and mix at 135°C-165°C to obtain aggregate;

[0058] 6. Take the modified asphalt and aggregate mass ratio of 11.5:187.5, stir and mix at 140℃~160℃, and cure at 170℃~190℃ to obtain rubber modified asphalt mixture.

[0059] Comparative Example 4

[0060] 1. Heat 100 parts of base asphalt at 130-140°C to a fluid state, add 1.5 parts of 1-benzyloxy-3-isopropoxy-2-propanol at 60-70°C and 55 parts of distilled water at 60-70°C while stirring, and keep stirring for 30 minutes after the addition is completed;

[0061] 2. The emulsified asphalt is heated to 150°C, and 25 parts of rubber powder at 135°C are added while stirring. After the addition is completed, stirring is continued for 30 minutes to obtain mixture A;

[0062] 3. Mixture A was transferred to a shearing device and sheared at 180°C for 45 minutes. After the shearing, it was placed at 175°C for 1 hour to obtain modified asphalt;

[0063] 4. Take 140 parts of coarse aggregate with a particle size of 2.36-16 mm, 45 parts of fine aggregate with a particle size of 0.075-2.36 mm, 20 parts of filler with a particle size less than 0.075 mm, and 0.45 parts of polyamide polyurea formaldehyde resin, stir and mix at 135°C-165°C to obtain aggregate;

[0064] 5. Take the modified asphalt and aggregate mass ratio of 11.5:187.5, stir and mix at 140℃~160℃, and cure at 170℃~190℃ to obtain rubber modified asphalt mixture.

[0065] Comparative Example 5

[0066] 1. Take vulcanized styrene-butadiene rubber and rubber powder in a mass ratio of 1:1, heat until they have fluidity, combine and stir to obtain a modifier;

[0067] 2. Heat 100 parts of base asphalt at 130-140°C to a fluid state, add 1.5 parts of 1-benzyloxy-3-isopropoxy-2-propanol at 60-70°C and 55 parts of distilled water at 60-70°C while stirring, and keep stirring for 30 minutes after the addition is completed;

[0068] 3. The emulsified asphalt is heated to 150°C, and 10 parts of modifier at 135°C are added while stirring. After the addition is completed, stirring is continued for 30 minutes to obtain mixture A;

[0069] 4. Mixture A was transferred to a shearing device and sheared at 180°C for 45 minutes. After the shearing, it was transferred to 175°C for 1 hour to obtain modified asphalt;

[0070] 5. Take 140 parts of coarse aggregate with a particle size of 2.36-16 mm, 45 parts of fine aggregate with a particle size of 0.075-2.36 mm, 20 parts of filler with a particle size less than 0.075 mm, and 0.45 parts of polyamide polyurea formaldehyde resin, stir and mix at 135°C-165°C to obtain aggregate;

[0071] 6. Take the modified asphalt and aggregate mass ratio of 11.5:187.5, stir and mix at 140℃~160℃, and cure at 170℃~190℃ to obtain rubber modified asphalt mixture.

[0072] Comparative Example 6

[0073] 1. Take vulcanized styrene-butadiene rubber and rubber powder in a mass ratio of 1:1, heat until they have fluidity, combine and stir to obtain a modifier;

[0074] 2. Heat 100 parts of base asphalt at 130-140°C to a fluid state, add 1.5 parts of 1-benzyloxy-3-isopropoxy-2-propanol at 60-70°C and 55 parts of distilled water at 60-70°C while stirring, and keep stirring for 30 minutes after the addition is completed;

[0075] 3. The emulsified asphalt was heated to 150°C, and 40 parts of the modifier at 135°C was added while stirring. After the addition was completed, stirring was continued for 30 minutes to obtain a mixture A;

[0076] 4. Mixture A was transferred to a shearing device and sheared at 180°C for 45 minutes. After the shearing, it was transferred to 175°C for 1 hour to obtain modified asphalt;

[0077] 5. Take 140 parts of coarse aggregate with a particle size of 2.36-16 mm, 45 parts of fine aggregate with a particle size of 0.075-2.36 mm, 20 parts of filler with a particle size less than 0.075 mm, and 0.45 parts of polyamide polyurea formaldehyde resin, stir and mix at 135°C-165°C to obtain aggregate;

[0078] 6. Take the modified asphalt and aggregate mass ratio of 11.5:187.5, stir and mix at 140℃~160℃, and cure at 170℃~190℃ to obtain rubber modified asphalt mixture.

[0079] Comparative Example 7

[0080] The difference between this comparative example and Example 4 is that the polyamide polyurea formaldehyde resin in step 4 is urea formaldehyde resin, and the rest of the implementation is the same as Example 1.

[0081] Comparative Example 8

[0082] 1. Take vulcanized styrene-butadiene rubber and rubber powder in a mass ratio of 1:1, heat until they have fluidity, combine and stir to obtain a modifier;

[0083] 2. Heat 100 parts of base asphalt at 130-140°C to a fluid state, add 1.5 parts of 1-benzyloxy-3-isopropoxy-2-propanol at 60-70°C and 55 parts of distilled water at 60-70°C while stirring, and keep stirring for 30 minutes after the addition is completed;

[0084] 3. The emulsified asphalt is heated to 150°C, and 25 parts of the modifier at 135°C are added while stirring. After the addition is completed, stirring is continued for 30 minutes to obtain a mixture A;

[0085] 4. Mixture A was transferred to a shearing device and sheared at 180°C for 45 minutes. After the shearing, it was placed at 175°C for 1 hour to obtain modified asphalt;

[0086] 5. Take 140 parts of coarse aggregate with a particle size of 2.36-16 mm, 45 parts of fine aggregate with a particle size of 0.075-2.36 mm, 20 parts of filler with a particle size less than 0.075 mm, and 0.45 parts of polyamide polyurea formaldehyde resin, stir and mix at 135°C-165°C to obtain aggregate;

[0087] 6. Take the modified asphalt and aggregate mass ratio of 11.5:187.5, stir and mix at 140℃~160℃, and cure at 170℃~190℃ to obtain rubber modified asphalt mixture.

[0088] Comparative Example 9

[0089] 1. Take vulcanized styrene-butadiene rubber and rubber powder in a mass ratio of 1:1, heat until they have fluidity, combine and stir to obtain a modifier;

[0090] 2. Heat 100 parts of base asphalt at 130-140°C to a fluid state, add 1.5 parts of 1-benzyloxy-3-isopropoxy-2-propanol at 60-70°C and 55 parts of distilled water at 60-70°C while stirring, and keep stirring for 30 minutes after the addition is completed;

[0091] 3. The emulsified asphalt is heated to 150°C, and 25 parts of the modifier at 135°C are added while stirring. After the addition is completed, stirring is continued for 30 minutes to obtain a mixture A;

[0092] 4. Mixture A was transferred to a shearing device and sheared at 180°C for 45 minutes. After the shearing, it was placed at 175°C for 1 hour to obtain modified asphalt;

[0093] 5. Take 140 parts of coarse aggregate with a particle size of 2.36-16 mm, 45 parts of fine aggregate with a particle size of 0.075-2.36 mm, 20 parts of filler with a particle size less than 0.075 mm, and 0.45 parts of polyamide polyurea formaldehyde resin, stir and mix at 135°C-165°C to obtain aggregate;

[0094] 6. Take the modified asphalt and aggregate mass ratio of 11.5:187.5, stir and mix at 140℃~160℃, and cure at 170℃~190℃ to obtain rubber modified asphalt mixture.

[0095] Product determination:

[0096] Asphalt mixture samples were prepared according to Examples 1-3 and Comparative Examples 1-9 respectively;

[0097] 1. Stability: 100 kg of samples were sampled from each case, and four specimens were prepared for each case according to the standard Marshall test requirements. The stability data were measured using an automatic Marshall tester, and the average value of the four results was taken, as shown in Table 1.

[0098] 2. Water stability (residual stability): 100 kg of each sample was sampled and four specimens were prepared for each case according to the requirements of the water immersion Marshall test. The water stability data was measured using an automatic Marshall tester and the average value of the four results was taken, as shown in Table 1.

[0099] 3. High temperature stability: For each sample, four specimens with a length of 300 mm, a width of 300 mm, and a thickness of 50 mm were prepared using a wheel rolling forming machine. The test temperature was 70°C and the wheel pressure was 1.4 MPa. 45 minutes after the start of the test, the average value of the four results was taken, as shown in Table 1.

[0100] 4. Low temperature crack resistance (failure strain): For each sample, a plate with a length of 300 mm, a width of 300 mm, and a thickness of 50 mm was prepared using a wheel rolling forming machine. Five prism specimens with a length of 250 mm, a width of 30 mm, a height of 35 mm, and a span of 200 mm were obtained by cutting. The creep testing machine was used to test at 0°C, and the average value of the five results was taken, as shown in Table 1.

[0101] Table 1

[0102] Stability (kN) Dynamic stability times (times / mm) Failure strain (με) Residual stability (%) Example 1 15.3±0.4 3671±13 4539±17 93.5±1.2 Example 2 15.1±0.3 3682±19 4547±13 92.4±1.4 Example 3 15.4±0.6 3669±11 4533±18 94.1±1.4 Comparative Example 1 12.5±0.5 3448±15 4498±14 87.9±1.3 Comparative Example 2 13.7±0.7 3537±17 4512±16 86.8±1.7 Comparative Example 3 14.8±0.4 3594±18 4465±19 90.4±2.1 Comparative Example 4 14.8±0.5 3245±13 4071±15 90.3±1.3 Comparative Example 5 14.9±0.3 3367±15 4217±14 89.2±1.4 Comparative Example 6 14.7±0.3 3612±16 4502±17 88.7±1.1 Comparative Example 7 14.8±0.5 3342±12 4512±15 81.7±2.2 Comparative Example 8 14.6±0.4 3412±15 4495±19 83.4±1.6 Comparative Example 9 14.9±0.6 3601±14 4489±17 90.7±1.9

Claims

1. A rubber modified asphalt mixture, characterized in that: The preparation steps are as follows: (1) Heat 100 parts of base asphalt at 130-140°C until it becomes fluid, add 1-2 parts of emulsifier at 60-70°C and 50-60 parts of distilled water at 60-70°C while stirring, and keep stirring for 30 minutes after the addition is complete; (2) The emulsified asphalt is heated to 150°C, and 20-30 parts of a modifier at 135°C is added while stirring. After the addition is complete, stirring is continued for 30 minutes to obtain a mixture A. (3) Mixture A is transferred to a shearing device and sheared at 180°C for 45 min. After the shearing is completed, it is transferred to 175°C for 1 h to obtain modified asphalt; (4) 120-160 parts of coarse aggregate with a particle size of 2.36-16 mm, 30-60 parts of fine aggregate with a particle size of 0.075-2.36 mm, 10-30 parts of filler with a particle size less than 0.075 mm, and 0.3-0.6 parts of additives are stirred and mixed at 135°C-165°C to obtain aggregate; (5) Take the modified asphalt and aggregate in a mass ratio of 10-13:180-195, stir and mix at 140°C-160°C, and cure at 170°C-190°C to obtain a rubber modified asphalt mixture.

2. A rubber modified asphalt mixture as claimed in claim 1, characterized in that: The emulsifier is 1-benzyloxy-3-isopropoxy-2-propanol.

3. The rubber modified asphalt mixture according to claim 1, characterized in that: The modifier is a mixture of 50% vulcanized styrene-butadiene rubber and 50% rubber powder.

4. The rubber modified asphalt mixture according to claim 1, characterized in that: The additive is polyamide polyurea formaldehyde resin.