High-solid-content polymer compound emulsified asphalt and preparation method thereof

Abstract

The invention discloses high-solid-content polymer compound emulsified asphalt and a preparation method thereof, and belongs to the technical field of road engineering materials. The preparation method comprises the following steps: firstly, modifying matrix asphalt by using SBS; dissolving a cationic emulsifier in water, adjusting the pH value to 2-3 to obtain a soap liquid, and mixing the soap liquid with SBR latex to obtain a composite emulsified soap liquid; and finally, shearing and emulsifying the SBS modified asphalt and the composite emulsified soap liquid through a horizontal colloid mill, adding the defoaming agent and the thickening agent, and uniformly mixing to obtain the SBS modified asphalt. According to the preparation method, the horizontal colloid mill is adopted as emulsifying equipment, process parameters are optimized, the emulsifying problem of the high-viscosity SBS modified asphalt is successfully solved, the solid content of the prepared emulsified asphalt is larger than 65%, and the prepared emulsified asphalt has excellent storage stability and use performance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of road engineering materials, and particularly relates to a high-solid-content polymer compounded emulsified asphalt and a preparation method thereof. BACKGROUND

[0002] As an environmentally friendly and energy-saving pavement material, emulsified asphalt has been widely used in pavement preventive maintenance engineering because it does not need to be heated in production and construction, which can significantly reduce energy consumption and carbon emissions. In order to improve its road performance, styrene-butadiene-styrene block copolymer (SBS) and other polymers are usually used for modification. However, this brings two levels of great technical challenges. First, the addition of SBS will greatly increase the viscosity of asphalt and give it significant elasticity, which brings great difficulty to the emulsification process. Conventional emulsification equipment is difficult to effectively disperse the high viscoelastic SBS modified asphalt into stable and uniform micron-sized droplets. Second, in order to improve transportation efficiency and construction performance, high solid content (solid content > 65%) emulsified asphalt has become a development trend, but this further aggravates the instability of the system because the distance between dispersed asphalt particles is smaller and coalescence or demulsification is more likely to occur. When the two difficulties of high polymer content and high solid content are superimposed, the preparation difficulty increases exponentially. The prior art discloses a modified emulsified asphalt, which mentions that SBS or styrene-butadiene rubber (SBR) and other modifiers can be selected, but the polymer content (2-6%) given is low, and it does not involve high solid content systems, nor does it provide any specific technical solutions to overcome the difficulty of emulsifying high-viscosity asphalt. The prior art also discloses a preparation method of SBS and SBR double-modified emulsified asphalt, which adds solid SBS and SBR rubber together into the base asphalt before emulsification for modification. This method will make the viscosity of the asphalt to be emulsified reach a very high level, making the subsequent emulsification extremely difficult, and it is difficult to form a stable emulsion with small particles and uniform distribution, especially not suitable for preparing high solid content products. Therefore, it is necessary to develop a polymer compounded emulsified asphalt with high solid content, high total polymer content and excellent storage stability. SUMMARY

[0003] In view of the above prior art, the present application discloses a high solid content polymer compounded emulsified asphalt and a preparation method thereof, to solve the technical problems in the prior art that high viscosity of asphalt leads to difficulty in emulsification, and high solid content leads to unstable performance of emulsified asphalt.

[0004] In order to achieve the above purpose, the technical scheme adopted by the present application is to provide a preparation method of a high solid content polymer compounded emulsified asphalt, which comprises the following steps: S1: mixing base asphalt, softening agent and SBS, and sequentially performing swelling, shearing and development treatment to obtain SBS modified asphalt; S2: Dissolve the cationic emulsifier in water, adjust the pH value to 2-3 to obtain a soap solution, then mix the soap solution with the SBR latex uniformly to obtain a composite emulsified soap solution; S3: Heat the SBS modified asphalt to 190-210 DEG C, heat the composite emulsified soap solution to 60-70 DEG C, then add the heated SBS modified asphalt and the heated composite emulsified soap solution into a horizontal colloidal mill, cut for 2-4 min at a rotating speed of 2900 rpm, then continuously add the defoaming agent and the thickening agent, mix uniformly to obtain the product.

[0005] On the basis of the above technical scheme, the application can be further improved as follows.

[0006] Further, the softening agent is an environmentally-friendly aromatic hydrocarbon oil, and the mass ratio of the base asphalt, the softening agent and the SBS is 100:4:4-8.

[0007] Further, the swelling treatment condition is stirring at 1000 rpm for 1 h at 165-175 DEG C, the shearing treatment condition is stirring at 6500 rpm for 1 h at 170-180 DEG C, and the development treatment condition is stirring at 500 rpm for 30 min at 160-170 DEG C.

[0008] Further, the cationic emulsifier is Redicote EM44 emulsifier, and the mass ratio of the base asphalt and the cationic emulsifier is 100:2.46-4.92.

[0009] Further, the mass ratio of the base asphalt and the SBR latex is 100:3-11.

[0010] Further, the mass ratio of the SBS modified asphalt and the composite emulsified soap solution is 13:6.

[0011] Further, the defoaming agent is a silicone defoaming agent, and the thickening agent is methyl cellulose.

[0012] Further, the mass ratio of the base asphalt, the defoaming agent and the thickening agent is 100:0.113:0.12.

[0013] The application has the following beneficial effects: 1、The application can play a synergistic effect on improving the storage stability of emulsified asphalt by compounding SBS and SBR latex in a specific proportion range; the application first adds SBR latex into the emulsifier soap solution to form a composite emulsifying soap solution, and then emulsifies the SBS modified asphalt, so that the SBR polymer participates in the construction of the interface film at the moment when the asphalt microdroplets are formed, and a composite emulsion system with stable structure and excellent performance is formed; the horizontal colloid mill is used as the emulsifying equipment, which has ultrahigh shear force and forced material circulation capacity, and can effectively break and disperse the asphalt phase with extremely high viscoelasticity. Through the integration of the above formula, equipment and process, a high-performance emulsified asphalt product with a solid content of more than 65% and a 1d storage stability of less than 1% is successfully prepared, which provides a reliable, complete and creative technical scheme for the industrial production and engineering application of this kind of environment-friendly pavement material. DETAILED DESCRIPTION

[0014] The specific embodiments of the application will be described in detail below with reference to the examples.

[0015] Example 1 A high solid content polymer compounded emulsified asphalt, a preparation method thereof comprises the following steps: S1: 100 parts by mass of 70# base asphalt is heated to 165℃, then 4 parts by mass of environment-friendly aromatic oil is added into the molten asphalt, after stirring uniformly, 8 parts by mass of linear SBS particles (block ratio is 40 / 60) is added, then stirring and swelling under the condition of temperature 170℃ and rotation speed 1000rpm for 1h, then increasing the temperature to 175℃, increasing the rotation speed to 6500rpm for high speed shearing for 1h, finally decreasing the temperature to 170℃, stirring at the rotation speed of 500rpm for 30min, then SBS modified asphalt is obtained.

[0016] S2: according to the mass parts of 70# base asphalt, 3.28 parts by mass of Redicote EM44 emulsifier is dissolved in water, and the pH value of the solution is adjusted to 2.5 by hydrochloric acid to obtain a soap solution, then 7 parts by mass of SBR latex is added into the soap solution, after stirring uniformly, a composite emulsifying soap solution is prepared; S3: the SBS modified asphalt is heated to 200℃, the composite emulsifying soap solution is heated to 65℃, then the SBS modified asphalt and the composite emulsifying soap solution are added into the horizontal colloid mill in a mass ratio of 13:6 for emulsification, the motor power of the horizontal colloid mill is 3kW, and the forced circulation shearing is carried out at the rotation speed of 2900rpm for 3min, then 0.113 parts by mass of BYK-019 organic silicon defoaming agent and 0.12 parts by mass of methyl cellulose are added, after mixing uniformly, it is obtained.

[0017] Example 2 A high solid content polymer compounded emulsified asphalt, a preparation method thereof comprises the following steps: S1: Heat 100 parts by weight of 70# base asphalt to 165℃, then add 4 parts by weight of environmentally friendly aromatic oil to the molten asphalt, stir evenly, then add 4 parts by weight of linear SBS particles (block ratio of 40 / 60), and stir and swell at 165℃ and 1000 rpm for 1 hour. Then raise the temperature to 170℃ and increase the speed to 6500 rpm for high-speed shearing for 1 hour. Finally, cool down to 160℃ and stir at 500 rpm for 30 minutes to obtain SBS modified asphalt.

[0018] S2: Based on the mass of 70# base asphalt, take 2.46 parts by mass of Redicote EM44 emulsifier and dissolve it in water. Adjust the pH of the solution to 2 with hydrochloric acid to obtain soap solution. Then take 11 parts by mass of SBR latex and add it to the soap solution. Stir evenly to obtain composite emulsified soap solution. S3: Heat the SBS modified asphalt to 190℃ and the composite emulsified soap solution to 60℃. Then, add the SBS modified asphalt and the composite emulsified soap solution to a horizontal colloid mill at a mass ratio of 13:6 for emulsification. The motor power of the horizontal colloid mill is 3kW, and the mill is subjected to forced cyclic shearing at a speed of 2900rpm for 2 minutes. Then, add 0.113 parts by mass of BYK-019 silicone defoamer and 0.12 parts by mass of methylcellulose, mix evenly, and the product is obtained.

[0019] Example 3 A high-solids-content polymer-blended emulsified asphalt, the preparation method of which includes the following steps: S1: Heat 100 parts by weight of 70# base asphalt to 165℃, then add 4 parts by weight of environmentally friendly aromatic oil to the molten asphalt, stir evenly, then add 6 parts by weight of linear SBS particles (block ratio of 40 / 60), and stir and swell at 175℃ and 1000 rpm for 1 hour. Then raise the temperature to 180℃ and increase the speed to 6500 rpm for high-speed shearing for 1 hour. Finally, cool down to 165℃ and stir at 500 rpm for 30 minutes to obtain SBS modified asphalt.

[0020] S2: Based on the mass of 70# base asphalt, take 4.92 parts by mass of Redicote EM44 emulsifier and dissolve it in water. Adjust the pH of the solution to 3 with hydrochloric acid to obtain soap solution. Then take 3 parts by mass of SBR latex and add it to the soap solution. Stir evenly to obtain composite emulsified soap solution. S3: Heat the SBS modified asphalt to 210℃ and the composite emulsified soap solution to 70℃. Then, add the SBS modified asphalt and the composite emulsified soap solution to a horizontal colloid mill at a mass ratio of 13:6 for emulsification. The motor power of the horizontal colloid mill is 3kW, and the mill is subjected to forced cyclic shearing at a speed of 2900rpm for 4 minutes. Then, add 0.113 parts by mass of BYK-019 silicone defoamer and 0.12 parts by mass of methylcellulose, mix evenly, and the product is obtained.

[0021] The differences in process parameters between Comparative Examples 1-7 and Example 1 are shown in Table 1.

[0022] Table 1

[0023] Comparative Example 8 An emulsified asphalt preparation method differs from that of Example 1 in that, in step S2, SBR latex is not added to the soap solution to obtain a composite emulsified soap solution. Instead, in step S3, SBS modified asphalt and soap solution are emulsified in a horizontal colloid mill to obtain SBS emulsified asphalt, and then SBR latex is added to the SBS emulsified asphalt.

[0024] Comparative Example 9 The difference between its preparation method and Example 1 is that in step S2, SBR latex is not added to the soap solution to obtain a composite emulsified soap solution. Instead, solid SBR rubber is used to replace SBR latex, and in step S1, solid SBR rubber, 70# base asphalt, environmentally friendly aromatic oil and linear SBS particles are blended to modify the base asphalt.

[0025] Comparative Example 10 The difference between the preparation method and Example 1 is that the horizontal colloid mill in step S3 is replaced with a vertical colloid mill with a rotation speed of 2900 rpm (model JM-L65).

[0026] Comparative Example 11 The difference between the preparation method and Example 1 is that the horizontal colloid mill in step S3 is replaced with a high-speed shear mixer, and the shear rate is set to 5700 rpm.

[0027] Experimental Example The emulsified asphalt prepared in Example 1 was tested and found to have a solid content of 73.2%.

[0028] The 1-day storage stability of the emulsified asphalt prepared in the examples and comparative examples was tested, and the results are shown in Table 2.

[0029] Table 2

[0030] The particle size test results of emulsified asphalt in Examples 1-3 and Comparative Examples 2-7 are shown in Table 3.

[0031] Table 3

[0032] In Comparative Example 1, the excessive SBS content and the imbalance in the SBS to SBR ratio led to a significant decrease in the storage stability of the emulsified asphalt. In contrast, in Example 1, the SBS:SBR mass ratio was 8:7, resulting in excellent emulsified asphalt stability. Comparative Examples 2-7, which altered key process parameters in their preparation methods, also exhibited significantly reduced storage stability of the emulsified asphalt, indirectly demonstrating that the process parameters in this invention achieve optimal technical results. Comparative Example 8, which employed an external admixture method, successfully emulsified the material, but the emulsion exhibited high viscosity and poor stability. In this invention, the horizontal colloid mill, due to its unique forced circulation and high-shear design, ensures that highly viscous materials receive sufficient residence time and energy input in the shear zone. Vertical colloid mills and high-speed shear mills cannot achieve this technical effect, resulting in emulsification failures in Comparative Examples 9-11.

[0033] Although specific embodiments of the present invention have been described in detail with reference to examples, they should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by those skilled in the art without inventive effort within the scope described in the claims are still within the scope of protection of this patent.

Claims

1. A method for preparing high-solids-content polymer-blended emulsified asphalt, characterized in that, Includes the following steps: S1: Base asphalt, softener and SBS are mixed and then subjected to swelling, shearing and development treatments in sequence to obtain SBS modified asphalt; S2: Dissolve the cationic emulsifier in water, adjust the pH value to 2-3 to obtain soap solution, and then mix the soap solution with SBR latex evenly to obtain composite emulsified soap solution; S3: Heat the SBS modified asphalt to 190~210℃, heat the composite emulsified soap solution to 60~70℃, then add the heated SBS modified asphalt and the heated composite emulsified soap solution to a horizontal colloid mill and shear at 2900rpm for 2~4min, then continue to add defoamer and thickener, and mix evenly to obtain the final product.

2. The method for preparing high-solids-content polymer-blended emulsified asphalt according to claim 1, characterized in that, The softener is an environmentally friendly aromatic oil, and the mass ratio of the base asphalt, softener and SBS is 100:4:4~8.

3. The method for preparing high-solids-content polymer-blended emulsified asphalt according to claim 1, characterized in that: The swelling treatment was carried out at 165-175℃ and stirred at 1000 rpm for 1 hour; the shearing treatment was carried out at 170-180℃ and stirred at 6500 rpm for 1 hour; and the development treatment was carried out at 160-170℃ and stirred at 500 rpm for 30 minutes.

4. The method for preparing high-solids-content polymer-blended emulsified asphalt according to claim 1, characterized in that: The cationic emulsifier is Redicote EM44 emulsifier, and the mass ratio of the base asphalt to the cationic emulsifier is 100:2.46~4.

92. The amount of cationic emulsifier used is 1.5 to 3% of the total mass of the high solids content polymer compound emulsified asphalt.

5. The method for preparing high-solids-content polymer-blended emulsified asphalt according to claim 1, characterized in that: The mass ratio of base bitumen to SBR latex is 100:3~11.

6. The method for preparing high-solids-content polymer-blended emulsified asphalt according to claim 1, characterized in that: The mass ratio of SBS modified bitumen to composite emulsified soap solution is 13:

6.

7. The method for preparing high-solids-content polymer-blended emulsified asphalt according to claim 1, characterized in that: The defoamer is an organosilicon defoamer, and the thickener is methylcellulose.

8. The method for preparing high-solids-content polymer-blended emulsified asphalt according to claim 7, characterized in that: The mass ratio of base asphalt, defoamer, and thickener is 100:0.113:0.

12.

9. The high-solids-content polymer-blended emulsified asphalt prepared by the method for preparing high-solids-content polymer-blended emulsified asphalt according to claims 1 to 8.

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