Preparation method of high-viscosity modified emulsified asphalt

Abstract

The invention relates to a preparation method of high-viscosity modified emulsified asphalt, which comprises the following steps: 1) preserving heat of matrix asphalt, adding a modifier and a viscosity reducer in sequence, and shearing and stirring in sequence; 2) adding a cross-linking agent, stirring and preserving heat to obtain hot asphalt; 3) adding an emulsifier into water, and adjusting the pH value of the solution to be acidic to obtain liquid soap; and 4) mixing the hot asphalt in the step 2) and the soap liquid in the step 3), and shearing to obtain the high-viscosity modified emulsified asphalt. Compared with the prior art, the preparation method has the advantages that the cross-linking agent is utilized, the cross-linking agent and the modifier can form a cross-linked network structure in the asphalt, the high and low temperature performance and the bonding performance of the asphalt are improved, the used viscosity reducer can reduce the high-temperature viscosity of the high-viscosity modified asphalt, and the emulsification and storage stability of the high-viscosity modified asphalt meet the standard requirements; the preparation process is simple, easy to operate, low in cost and easy to popularize and apply in practical engineering.

Description

Technical Field

[0001] The present invention belongs to the technical field of traffic engineering building materials, and relates to a method for preparing a high-viscosity modified emulsified asphalt, and specifically relates to a cross-linking-emulsification synergistically regulated high-viscosity modified emulsified asphalt and a preparation method thereof. Background Art

[0002] Asphalt pavement has the advantages of comfortable driving, simple maintenance, flatness and less dust. It is the main pavement structure form for high-grade highways and urban roads. Hot-mix asphalt mixture has excellent road performance, but the construction temperature is relatively high, about 170°C, which does not meet the national strategic needs of sustainable development. Cold-mix asphalt mixture can be constructed at room temperature, which is green and environmentally friendly and has great prospects for promotion and application. Among them, emulsified cold-mix asphalt mixture technology is relatively mature and has a high cost-effectiveness, but its high and low temperature and bonding properties are poor, and it is mostly used for road maintenance. Solvent-based cold-mix asphalt mixture contains flammable and explosive solvents and pollutes the environment, so it is mostly used for pothole repair. With the development of high-molecular polymer modifiers, the road performance of emulsified cold-mix asphalt mixture has been significantly improved, and it has the potential to be applied to the surface layer of the road. However, the current problem is that the viscosity of high-viscosity modified emulsified asphalt is relatively large, the requirements for emulsification equipment are high, and it is difficult to emulsify. Summary of the invention

[0003] The purpose of the present invention is to provide a method for preparing high-viscosity modified emulsified asphalt in order to overcome the defects of the above-mentioned prior art.

[0004] The purpose of the present invention can be achieved by the following technical solutions:

[0005] The preparation method of high-viscosity modified emulsified asphalt provided by the present invention involves determining the type and dosage of a cross-linking agent and the type and dosage of a viscosity reducer. Determining the type and dosage of the cross-linking agent includes determining the morphological structure and performance indicators of the cross-linking agent in the asphalt, and determining the type and dosage of the viscosity reducer includes determining the rotational viscosity of the asphalt at the emulsification temperature (175°C).

[0006] The present invention provides a method for preparing a high-viscosity modified emulsified asphalt, the method comprising the following steps:

[0007] 1) After the base asphalt is kept warm, a modifier and a viscosity reducer are added successively and sheared and stirred;

[0008] 2) adding a cross-linking agent, stirring and keeping warm to obtain hot asphalt;

[0009] 3) adding an emulsifier to water and adjusting the pH of the solution to acidic to obtain a soap solution;

[0010] 4) The hot asphalt in step 2) and the soap solution in step 3) are mixed and sheared to obtain a high-viscosity modified emulsified asphalt.

[0011] Further, the mass ratio of the base asphalt, modifier, viscosity reducer and cross-linking agent is 100:(5.0-6.0):(5.0-6.0):(0.1-0.2). Preferably, the mass ratio of the base asphalt, modifier, viscosity reducer and cross-linking agent is 100:6.0:6.0:0.1.

[0012] Furthermore, the modifier is styrene-butadiene-styrene triblock copolymer (SBS YH-791H); the viscosity reducer is rubber oil; and the cross-linking agent is industrial sulfur.

[0013] Furthermore, in step 1), during the insulation, the insulation temperature is 150-165°C, and the insulation time is 1-2h; during the shearing, the shearing temperature is 170-175°C, the shearing speed is 3800-4300r / min, and the shearing time is 0.4-0.6h; during the stirring, the stirring temperature is 170-175°C, the stirring speed is 400-600r / min, and the stirring time is 1-1.5h.

[0014] Further preferably, in step 1), the insulation temperature is 160°C and the insulation time is 1h; the shearing temperature is 170°C, the shearing speed is 4000r / min and the shearing time is 0.5h; the stirring temperature is 170°C, the stirring speed is 500r / min and the stirring time is 1h, so that the modifier is fully developed and swollen in the asphalt.

[0015] Furthermore, in step 2), during the stirring, the stirring temperature is 170-175°C, the stirring speed is 400-600r / min, and the stirring time is 1-1.5h; during the insulation, the insulation temperature is 170-175°C, and the insulation time is 2-4h; the temperature of the hot asphalt is 170-175°C.

[0016] Further preferably, in step 2), during the stirring, the stirring temperature is 170° C., the stirring speed is 500 r / min, and the stirring time is 1 hour; during the heat preservation, the heat preservation temperature is 175° C., and the heat preservation time is 3 hours; the temperature of the hot asphalt is 175° C. The carbon free radicals in the asphalt are combined to form CS bonds, forming a network cross-linked structure, thereby improving the road performance of the asphalt.

[0017] Furthermore, in step 2), the rotational viscosity of the asphalt after stirring at 175° C. is less than 0.5 Pa.s.

[0018] Furthermore, the rotational viscosity is measured by performing a rotational viscosity test on the asphalt after stirring at 175°C.

[0019] Further, in step 3), the temperature of the water is 55-65°C; the temperature of the soap solution is 55-65°C;

[0020] Further preferably, in step 3), the temperature of the water is 60°C; the temperature of the soap solution is 60°C.

[0021] Furthermore, in step 3), phosphoric acid is used to adjust the pH of the solution to acidity, wherein the pH is 2-3.

[0022] Furthermore, in step 3), the mass ratio of the emulsifier, phosphoric acid and water is (4.0-5.5):(4.0-5.5):(48-50); the mass ratio of the base asphalt and the emulsifier is 100:(4.0-5.5). Preferably, the mass ratio of the emulsifier, phosphoric acid and water is 4.0:4.0:50; the mass ratio of the base asphalt and the emulsifier is 100:4.0.

[0023] Furthermore, in step 4), the mixing is carried out in a colloid mill, specifically: first pour the soap solution in step 3) into the colloid mill and start the colloid mill; then slowly add the hot asphalt in step 2) into the colloid mill, and form a water-in-oil high-viscosity modified emulsified asphalt through the high-speed shearing action of the colloid mill head.

[0024] Furthermore, the colloid mill is provided with a cooling device, and the temperature of the high-viscosity modified emulsified asphalt collected from the colloid mill should not be too high, generally around 85° C., in order to avoid demulsification and result in substandard quality.

[0025] Furthermore, in step 4), during the shearing, the shearing speed is 2840R / M and the shearing time is 1-3min.

[0026] Further preferably, in step 4), during the shearing, the shearing time is 2 min.

[0027] The present invention prepares a high-viscosity modified emulsified asphalt, preferably a suitable cross-linking agent (industrial sulfur) and a blending ratio, forming a network structure in the high-viscosity modified asphalt to improve the road performance of the asphalt. Secondly, in view of the problem that the high-viscosity modified asphalt has high viscosity and is difficult to emulsify, a suitable viscosity reducer (rubber oil) and a blending ratio are optimized to achieve emulsification of the high-viscosity modified asphalt, wherein the high-viscosity modified emulsified asphalt includes the following components by weight: 100 parts of base asphalt, 5.0-6.0 parts of modifier, 0.1-0.2 parts of cross-linking agent, 5.0-6.0 parts of viscosity reducer, 4.0-5.5 parts of emulsifier, 4.0-5.5 parts of phosphoric acid, and 48-50 parts of water.

[0028] Compared with the prior art, the present invention has the following characteristics:

[0029] 1) The greatest advantage of the present invention is that it innovatively utilizes rubber oil, which can reduce the high-temperature viscosity of high-viscosity modified asphalt, achieve emulsification of high-viscosity modified asphalt, and the storage stability meets the regulatory requirements;

[0030] 2) The cross-linking agent industrial sulfur used in the present invention can form a cross-linked network structure with the modifier in the asphalt, thereby improving the high and low temperature performance and bonding performance of the asphalt;

[0031] 3) The preparation process of the present invention is simple, easy to operate, and has low cost, and is easy to promote and apply in practical engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The microscopic surface morphology of the high-viscosity modified emulsified asphalt prepared in Example 1(a), Example 2(b), Comparative Example 1(c), and Comparative Example 2(d). DETAILED DESCRIPTION

[0033] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0034] The following are more detailed implementation cases, which further illustrate the technical solutions of the present invention and the technical effects that can be obtained.

[0035] In the following examples, unless otherwise specified, raw materials, reagents or processing techniques are all conventional commercial products or conventional processing techniques in the art.

[0036] In the following examples, the modifier is styrene-butadiene-styrene triblock copolymer (SBS YH-791H); the viscosity reducer is rubber oil; the crosslinking agent is industrial sulfur; and the model of the colloid mill is MD-1.

[0037] Example 1

[0038] A high-viscosity modified emulsified asphalt, the raw material composition and mass ratio are: 100 parts of base asphalt, 6 parts of modifier, 6 parts of viscosity reducer, 0.1 parts of cross-linking agent, 4 parts of emulsifier, 4 parts of phosphoric acid, and 50 parts of water. The preparation method is as follows:

[0039] 1) Place the base asphalt in a 160°C oven for 1 hour, then add the modifier and viscosity reducer to the base asphalt in turn, shear it with a high-speed shearing machine at 170°C and 4000 r / min for 0.5 h, and then stir it at a low speed at 170°C and 500 r / min for 1 hour to allow the modifier to fully develop and swell in the asphalt;

[0040] 2) Add a cross-linking agent to the asphalt prepared in step 1), and stir at a low speed of 170° C. and 500 r / min for 1 h to combine the carbon free radicals in the asphalt to form CS bonds and form a network cross-linked structure to obtain a high-viscosity modified asphalt; at this time, perform a rotational viscosity test at 175° C. on the high-viscosity modified asphalt to ensure that the rotational viscosity is less than 0.5 Pa.s, and prepare a high-viscosity modified asphalt that is easy to emulsify. If the rotational viscosity at 175° C. is greater than 0.5 Pa.s, the proportion of the viscosity reducer should be adjusted so that its rotational viscosity meets the requirements;

[0041] 3) placing the high-viscosity modified asphalt prepared in step 2) in an oven at 175° C. and heating for 3 h to obtain hot asphalt (175° C.);

[0042] 4) adding the emulsifier in a corresponding proportion to water at 60° C. and stirring continuously to obtain a mixed solution, then adjusting the pH of the mixed solution with phosphoric acid to a pH of about 2-3 to obtain a soap solution, and placing the soap solution in water at 60° C. to keep it warm for later use;

[0043] 5) Add hot water to the colloid mill, start the instrument, and run it for 2 minutes to preheat the colloid mill. After the end, release the water through the valve, then add the soap solution prepared in step 4) to the colloid mill, start the instrument, and pour the hot asphalt (175°C) in step 3) into the colloid mill for stirring. After the asphalt and soap solution are sheared at 2840R / M in the colloid mill for 2 minutes, they are released through the valve and cooled to room temperature to obtain high-viscosity modified emulsified asphalt, which is sealed and stored for later use.

[0044] Embodiment 2:

[0045] A high-viscosity modified emulsified asphalt, the preparation method of which is different from that of Example 1, except that: 5 parts of a modifier, 5 parts of a viscosity reducer, and 0.2 parts of a cross-linking agent. The rest is the same as that of Example 1.

[0046] Comparative Example 1:

[0047] A high-viscosity modified emulsified asphalt, the preparation method thereof is different from that of Example 1, except that no cross-linking agent is added, and accordingly, step 2 is omitted. The rest is the same as that of Example 1.

[0048] Comparative Example 2:

[0049] A high-viscosity modified emulsified asphalt, the preparation method of which is different from that of Example 1, except that no viscosity reducer is added. The rest is the same as that of Example 1.

[0050] Figure 1The microscopic surface morphology of the high-viscosity modified emulsified asphalt prepared in Example 1 (a), Example 2 (b), Comparative Example 1 (c), and Comparative Example 2 (d) show that, compared with the comparative examples, the SBS modifier in the examples is evenly distributed in the asphalt and forms a network cross-linked structure, so that the high-viscosity modified emulsified asphalt has better high and low temperature performance.

[0051] Relevant performance tests were conducted on the emulsification conditions, storage stability and high and low temperature performance indicators of the high-viscosity modified emulsified asphalt in Example 1-2 and Comparative Example 1-2 to evaluate the effectiveness of the cross-linking-emulsification synergistic regulation method of high-viscosity modified emulsified asphalt. The test results are shown in the following table.

[0052] Table 1 Test results of high viscosity modified emulsified asphalt performance

[0053]

[0054] It can be seen from the test results that both Examples 1-2 of the present invention and Comparative Example 1 can achieve the emulsification of high-viscosity modified asphalt, and the storage stability meets the requirements of the specification, while Comparative Example 2 does not add a viscosity reducer, resulting in a high viscosity of the modified asphalt, and the soap solution and asphalt are incompatible, resulting in emulsification failure. Although both Example 1 and Comparative Example 1 can achieve the emulsification of high-viscosity modified asphalt, and the storage stability meets the requirements of the specification, Comparative Example 1 does not add a cross-linking agent, and does not form a good network structure in the asphalt, resulting in low high and low temperature performance indicators. Although both Examples 1-2 can achieve the emulsification of high-viscosity modified asphalt, and the storage stability meets the requirements of the specification, the components of Example 1 are all in the optimal ratio, so the prepared high-viscosity modified emulsified asphalt exhibits good high and low temperature performance.

[0055] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing high-viscosity modified emulsified asphalt, characterized in that: The method comprises the following steps: 1) After the base asphalt is kept warm, a modifier and a viscosity reducer are added successively and sheared and stirred; 2) adding a cross-linking agent, stirring, and keeping warm to obtain hot asphalt; 3) adding an emulsifier to water and adjusting the pH of the solution to acidic to obtain a soap solution; 4) The hot asphalt in step 2) and the soap solution in step 3) are mixed and sheared to obtain a high-viscosity modified emulsified asphalt.

2. The method for preparing the high-viscosity modified emulsified asphalt according to claim 1, characterized in that: The mass ratio of the base asphalt, modifier, viscosity reducer and cross-linking agent is 100:(5.0-6.0):(5.0-6.0):(0.1-0.2).

3. The method for preparing the high-viscosity modified emulsified asphalt according to claim 1, characterized in that: The modifier is styrene-butadiene-styrene triblock copolymer; the viscosity reducer is rubber oil; and the crosslinking agent is industrial sulfur.

4. The method for preparing the high-viscosity modified emulsified asphalt according to claim 1, characterized in that: In step 1), during the insulation, the insulation temperature is 150-165°C, and the insulation time is 1-2h; during the shearing, the shearing temperature is 170-175°C, the shearing speed is 3800-4300r / min, and the shearing time is 0.4-0.6h; during the stirring, the stirring temperature is 170-175°C, the stirring speed is 400-600r / min, and the stirring time is 1-1.5h.

5. The method for preparing the high-viscosity modified emulsified asphalt according to claim 1, characterized in that: In step 2), during the stirring, the stirring temperature is 170-175°C, the stirring speed is 400-600r / min, and the stirring time is 1-1.5h; during the insulation, the insulation temperature is 170-175°C, and the insulation time is 2-4h; the temperature of the hot asphalt is 170-175°C.

6. The method for preparing the high-viscosity modified emulsified asphalt according to claim 1, characterized in that: In step 2), the rotational viscosity of the asphalt after stirring at 175° C. is less than 0.5 Pa.s.

7. The method for preparing the high-viscosity modified emulsified asphalt according to claim 1, characterized in that: In step 3), the temperature of the water is 55-65°C; the temperature of the soap solution is 55-65°C.

8. The method for preparing the high-viscosity modified emulsified asphalt according to claim 1, characterized in that: In step 3), phosphoric acid is used to adjust the solution pH to acidic, wherein the pH is 2-3.

9. The method for preparing the high-viscosity modified emulsified asphalt according to claim 8, characterized in that: In step 3), the mass ratio of the emulsifier, phosphoric acid and water is (4.0-5.5):(4.0-5.5):(48-50); the mass ratio of the base asphalt and the emulsifier is 100:(4.0-5.5).

10. The method for preparing the high-viscosity modified emulsified asphalt according to claim 1, characterized in that: In step 4), during the shearing, the shearing speed is 2840R / M and the shearing time is 1-3min.

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