A rubber modified asphalt mixture and a method of making the same

Abstract

The application discloses a rubber modified asphalt mixture and a preparation method thereof. The application adjusts the surface activity of asphalt by using an emulsifier, improves the performance of asphalt by using a modifier, and finally adjusts the weather resistance of the mixture by adding additional additives, so that a rubber modified asphalt mixture with good weather resistance and compression resistance is prepared.

Description

Technical Field

[0001] This invention relates to the field of road construction materials technology, and more specifically to a rubber-modified asphalt mixture and its preparation method. Background Technology

[0002] With the rapid development of global infrastructure construction, road engineering places increasingly higher demands on the performance of pavement materials. Asphalt mixtures, as one of the most widely used materials in road construction, directly affect the service life and driving safety of roads. Although traditional asphalt mixtures have good adhesion and stability, they are prone to deformation and cracking under harsh conditions such as high temperature, low temperature, and heavy traffic, thus affecting the performance of roads.

[0003] To improve the performance of asphalt mixtures, researchers have developed various modified asphalt technologies, such as SBS-modified asphalt and rubber-modified asphalt. These modified asphalts, by adding polymers, rubber, and other materials, improve the high-temperature stability and low-temperature crack resistance of asphalt. Although existing modified asphalt mixture technologies have improved the performance of pavement materials to some extent, problems remain. Under extreme climatic conditions, the performance improvement of existing modified asphalt mixtures is limited, and the durability of modified asphalt mixtures under long-term heavy traffic still needs improvement.

[0004] The focus of this invention is to provide a rubber-modified asphalt mixture that has good stability, compressive strength, and durability under extreme climatic conditions. Summary of the Invention

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

[0006] (1) Heat 100 parts of base asphalt at 130~140℃ to a fluid state, and add 1~2 parts of emulsifier at 60~70℃ and 50~60 parts of distilled water at 60~70℃ while stirring. After adding, keep stirring for 30 minutes.

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

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

[0009] (4) Take 120-160 parts of coarse aggregate with a particle size of 2.36-16mm, 30-60 parts of fine aggregate with a particle size of 0.075-2.36mm, 10-30 parts of filler with a particle size of less than 0.075mm, and 0.3-0.6 parts of additives, and stir and mix them at 135℃-165℃ to obtain aggregate;

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

[0011] 2. Further, the emulsifier is 1-benzoxy-3-isopropoxy-2-propanol.

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

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

[0014] The beneficial effects of this invention are as follows:

[0015] (1) This invention utilizes emulsifiers and modifiers to modify and optimize the base asphalt, and adds additives during the aggregate mixing process to improve the uniformity of aggregate particles. After the final mixing, the combined effect of various reagents comprehensively improves the stability, weather resistance and durability of the asphalt mixture.

[0016] (2) In this invention, rubber is incorporated into the asphalt. However, the compatibility between the base asphalt and the modifier is insufficient, and rubber is prone to precipitation. Therefore, the base asphalt needs to be emulsified with an emulsifier before modification. In this invention, 1-benzoxy-3-isopropoxy-2-propanol is used as an emulsifier. It has good surface activity and can promote the compatibility between rubber and asphalt. 1-benzoxy-3-isopropoxy-2-propanol can form a cavity structure on the surface of different phases by hydrogen bonds. Different substances in the system can be on both sides of the cavity structure, thereby improving the compatibility between different particles. In addition, it can assist in film formation, making the continuous phase in the asphalt mixture more numerous and denser, increasing the hardness of the asphalt mixture and improving its compressive strength.

[0017] (3) Common rubber-modified asphalt mixtures have limited modification effects on asphalt and can no longer meet the current needs. Therefore, additional modifiers are needed to mix and modify asphalt together with rubber powder. Vulcanized styrene-butadiene rubber has good mechanical and physicochemical properties. As a partial modifier, it is added to asphalt to avoid inhibiting fluidity and improve aging resistance and high and low temperature resistance. After vulcanized styrene-butadiene rubber is mixed into asphalt and swells, it absorbs the light components in the asphalt and hardens the asphalt components. It can also form a three-dimensional network structure miscible system with asphalt, which can effectively improve the wear resistance and compressive strength of asphalt mixtures and improve the physical properties of asphalt mixtures.

[0018] (4) In order to comprehensively improve the properties of the mixture and make up for the problem of the harsh construction environment requirements caused by the introduction of hydrophilic groups of 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 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) In this invention, polyamide polyurea formaldehyde resin is selected as an additive. It can form covalent and ionic bonds with the hydrophilic components in the asphalt mixture, thereby introducing hydrophobic effects. The polyamide polyurea formaldehyde resin can exhibit cationic properties in this system and can form micro-flocculation with anionic 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 Implementation

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

[0021] Unless otherwise specified, the raw materials used in the embodiments of this invention are 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 fluid, combine and stir to obtain the modifier;

[0024] 2. Heat 100 parts of base bitumen at 130~140℃ to a fluid state, and while stirring, add 1.5 parts of 1-benzoxy-3-isopropoxy-2-propanol at 60~70℃ and 55 parts of distilled water at 60~70℃. After the addition is complete, keep stirring for 30 minutes.

[0025] 3. Heat the emulsified asphalt to 150℃, and while stirring, add 25 parts of modifier at 135℃. After the addition is complete, continue stirring for 30 minutes to obtain mixture A.

[0026] 4. Mixture A was transferred to a shearing device and sheared at 180°C for 45 minutes. After 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 2.36-16mm, 45 parts of fine aggregate with a particle size of 0.075-2.36mm, 20 parts of filler with a particle size of less than 0.075mm, and 0.45 parts of polyamide-polyurea-formaldehyde resin, and stir and mix them at 135℃~165℃ to obtain aggregate;

[0028] 6. Take modified asphalt and aggregate in a mass ratio of 11.5:187.5, stir and mix them at 140℃~160℃, and cure them 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 fluid, combine and stir to obtain the modifier;

[0031] 2. Heat 100 parts of base asphalt at 130~140℃ to a fluid state, and while stirring, add 2 parts of 1-benzoxy-3-isopropoxy-2-propanol at 60~70℃ and 55 parts of distilled water at 60~70℃. After the addition is complete, keep stirring for 30 minutes.

[0032] 3. Heat the emulsified asphalt to 150℃, and while stirring, add 20 parts of modifier at 135℃. After the addition is complete, continue stirring for 30 minutes to obtain mixture A.

[0033] 4. Mixture A was transferred to a shearing device and sheared at 180°C for 45 minutes. After 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 2.36-16mm, 45 parts of fine aggregate with a particle size of 0.075-2.36mm, 20 parts of filler with a particle size of less than 0.075mm, and 0.3 parts of polyamide-polyurea-formaldehyde resin, and stir and mix them at 135℃~165℃ to obtain aggregate;

[0035] 6. Take modified asphalt and aggregate in a mass ratio of 11.5:187.5, stir and mix them at 140℃~160℃, and cure them 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 fluid, combine and stir to obtain the modifier;

[0038] 2. Heat 100 parts of base asphalt at 130~140℃ to a fluid state, and while stirring, add 1 part of 1-benzoxy-3-isopropoxy-2-propanol at 60~70℃ and 55 parts of distilled water at 60~70℃. After the addition is complete, keep stirring for 30 minutes.

[0039] 3. Heat the emulsified asphalt to 150℃, and while stirring, add 30 parts of modifier at 135℃. After the addition is complete, continue stirring for 30 minutes to obtain mixture A.

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

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

[0042] 6. Take modified asphalt and aggregate in a mass ratio of 11.5:187.5, stir and mix them at 140℃~160℃, and cure them 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-benzoxy-3-isopropoxy-2-propanol in step 1 is a dodecyl alcohol ester, and the rest of the implementation is the same as in 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 fluid, combine and stir to obtain the modifier;

[0047] 2. Heat 100 parts of base bitumen at 130~140℃ to a fluid state, and while stirring, add 0.5 parts of 1-benzoxy-3-isopropoxy-2-propanol at 60~70℃ and 55 parts of distilled water at 60~70℃. After the addition is complete, keep stirring for 30 minutes.

[0048] 3. Heat the emulsified asphalt to 150℃, and while stirring, add 25 parts of modifier at 135℃. After the addition is complete, continue stirring for 30 minutes to obtain mixture A.

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

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

[0051] 6. Take modified asphalt and aggregate in a mass ratio of 11.5:187.5, stir and mix them at 140℃~160℃, and cure them 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 fluid, combine and stir to obtain the modifier;

[0054] 2. Heat 100 parts of base asphalt at 130~140℃ to a fluid state, and while stirring, add 2.5 parts of 1-benzoxy-3-isopropoxy-2-propanol at 60~70℃ and 55 parts of distilled water at 60~70℃. After the addition is complete, keep stirring for 30 minutes.

[0055] 3. Heat the emulsified asphalt to 150℃, and while stirring, add 25 parts of modifier at 135℃. After the addition is complete, continue stirring for 30 minutes to obtain mixture A.

[0056] 4. Mixture A was transferred to a shearing device and sheared at 180°C for 45 minutes. After 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 2.36-16mm, 45 parts of fine aggregate with a particle size of 0.075-2.36mm, 20 parts of filler with a particle size of less than 0.075mm, and 0.45 parts of polyamide-polyurea-formaldehyde resin, and stir and mix them at 135℃~165℃ to obtain aggregate;

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

[0059] Comparative Example 4

[0060] 1. Heat 100 parts of base bitumen at 130~140℃ to a fluid state, and while stirring, add 1.5 parts of 1-benzoxy-3-isopropoxy-2-propanol at 60~70℃ and 55 parts of distilled water at 60~70℃. After the addition is complete, keep stirring for 30 minutes.

[0061] 2. Heat the emulsified asphalt to 150℃, and while stirring, add 25 parts of adhesive powder at 135℃. After the addition is complete, continue stirring 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 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 2.36-16mm, 45 parts of fine aggregate with a particle size of 0.075-2.36mm, 20 parts of filler with a particle size of less than 0.075mm, and 0.45 parts of polyamide-polyurea-formaldehyde resin, and stir and mix them at 135℃~165℃ to obtain aggregate;

[0064] 5. Take modified asphalt and aggregate in a mass ratio of 11.5:187.5, stir and mix them at 140℃~160℃, and cure them 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 fluid, combine and stir to obtain the modifier;

[0067] 2. Heat 100 parts of base bitumen at 130~140℃ to a fluid state, and while stirring, add 1.5 parts of 1-benzoxy-3-isopropoxy-2-propanol at 60~70℃ and 55 parts of distilled water at 60~70℃. After the addition is complete, keep stirring for 30 minutes.

[0068] 3. Heat the emulsified asphalt to 150℃, and while stirring, add 10 parts of modifier at 135℃. After the addition is complete, continue stirring 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 shearing, it was placed at 175°C for 1 hour to obtain modified asphalt.

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

[0071] 6. Take modified asphalt and aggregate in a mass ratio of 11.5:187.5, stir and mix them at 140℃~160℃, and cure them 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 fluid, combine and stir to obtain the modifier;

[0074] 2. Heat 100 parts of base bitumen at 130~140℃ to a fluid state, and while stirring, add 1.5 parts of 1-benzoxy-3-isopropoxy-2-propanol at 60~70℃ and 55 parts of distilled water at 60~70℃. After the addition is complete, keep stirring for 30 minutes.

[0075] 3. Heat the emulsified asphalt to 150℃, and while stirring, add 40 parts of modifier at 135℃. After the addition is complete, continue stirring for 30 minutes to obtain mixture A.

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

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

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

[0079] Comparative Example 7

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

[0081] Product testing:

[0082] Asphalt mixture samples were prepared according to Examples 1-3 and Comparative Examples 1-7, respectively.

[0083] 1. Stability: 100 kg of each sample was taken and four specimens were prepared for each case according to the standard Marshall test requirements. The stability data were measured by an automatic Marshall tester and the average of the four results was taken, as shown in Table 1.

[0084] 2. Water stability (residual stability): 100 kg of each sample was taken and four specimens were prepared for each case according to the requirements of the water immersion Marshall test. The water stability data were measured by an automatic Marshall tester and the average value of the four results was taken, as shown in Table 1.

[0085] 3. High temperature stability: Four specimens with a length of 300 mm, a width of 300 mm, and a thickness of 50 mm were prepared for each sample using a wheel rolling molding machine. The test was conducted using a rutting tester at a temperature of 70℃ and a wheel pressure of 1.4 MPa. After 45 minutes of testing, the average value of the four results was taken, as shown in Table 1.

[0086] 4. Low-temperature crack resistance (failure strain): Each sample was prepared into a plate with a length of 300 mm, a width of 300 mm, and a thickness of 50 mm using a roller mill. 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 tester was used to test the specimens at 0℃. The average value of the five results was taken, as shown in Table 1.

[0087] Table 1

[0088] Stability (kN) Number of times dynamic stability (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

Claims

1. A rubber modified asphalt mixture, characterized in that, The preparation steps are as follows: (1) 100 parts of base pitch is heated to a flow state at 130-140°C under stirring, 1-2 parts of emulsifier at 60-70°C, 50-60 parts of distilled water at 60-70°C are added, and stirring is kept for 30 min after the addition is completed; (2) the emulsified pitch is heated to 150°C under stirring, 20-30 parts of modifier at 135°C is added, and stirring is kept for 30 min after the addition is completed, to obtain a mixture A; (3) the mixture A is transferred to a shearing device, and shearing is performed at 180°C for 45 min, and then the shearing device is transferred to 175°C for 1 h, to obtain modified pitch; (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 of less than 0.075 mm, and 0.3-0.6 parts of additive are mixed under stirring at 135-165°C, to obtain aggregate; (5) 10-13 parts of modified pitch and 180-195 parts of aggregate are mixed under stirring at 140-160°C, and then solidification is performed at 170-190°C, to obtain rubber modified pitch mixture; the emulsifier is 1-benzyloxy-3-isopropoxy-2-propanol; the modifier is a mixture of 50% vulcanized butadiene styrene rubber and 50% rubber powder; the additive is polyamide polyurea formaldehyde resin.