SBS high-viscosity modified asphalt and preparation method thereof

Abstract

The invention belongs to the technical field of modified asphalt, and discloses SBS high-viscosity modified asphalt and a preparation method thereof. The SBS high-viscosity modified asphalt comprises the following raw materials in parts by mass: 77-89 parts of matrix asphalt, 4-9 parts of an SBS modifier, 0.1-0.5 part of a stabilizer, 5-8 parts of a swelling agent, 6-12 parts of a compatilizer and 0.1-1 part of a wax-based auxiliary agent, and the total mass of the raw materials is 100 parts. The furfural extract oil is used as a swelling agent, the vacuum residue is used as a compatilizer, an SBS molecular chain is induced to spontaneously stretch to form a three-dimensional network structure, and an asphalt-SBS transition interface layer is constructed to inhibit a phase separation phenomenon, so that efficient compound modification of SBS and asphalt can be realized under low-speed stirring.

Description

Technical Field

[0001] The present invention belongs to the technical field of modified asphalt, and particularly relates to an SBS high-viscosity modified asphalt and a preparation method thereof. Background Art

[0002] As an important road construction material, road asphalt plays an increasingly important role in modern transportation. Traditional modified asphalt is prone to problems such as high-temperature softening, low-temperature cracking, and poor durability, making it difficult to meet the needs of current modern highway construction. To reduce the costs of road maintenance and road reconstruction, and to meet the high loads of modern transportation and resist the influence of harsh climates, high-viscosity modified asphalt has become an indispensable core material for porous asphalt pavements due to its advantages such as good low-temperature performance, strong durability, and high compressive strength.

[0003] Nowadays, the most mature and widely used asphalt modification technology is polymer-modified asphalt, especially SBS-modified asphalt. Due to its unique hard and soft segment structure, SBS can not only provide strength to asphalt but also form a stable polymer network structure to encapsulate asphalt. Therefore, the viscosity of SBS-modified asphalt is much higher than that of other polymer-modified asphalts, and its high and low-temperature performance and fatigue resistance are more excellent, and it is widely used in the construction and maintenance projects of high-performance asphalt pavements.

[0004] However, the preparation of current SBS-modified asphalt relies on high-speed shearing. When the shearing speed is too low, the SBS particles are unevenly dispersed, the swelling effect in asphalt slows down, and it is difficult to form an ideal three-dimensional network structure, failing to achieve the expected modification effect. Moreover, high-speed shearing not only consumes a large amount of energy and increases production costs, but the high temperature and strong mechanical force generated by high-speed shearing are also likely to cause the breakage of polymer molecular chains, reducing the performance of modified asphalt. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an SBS-modified high-viscosity asphalt and a preparation method thereof in view of the deficiencies of the prior art. Using furfural extract oil as a swelling agent and vacuum residue as a compatibilizer, it induces the spontaneous stretching of SBS molecular chains to form a three-dimensional network structure, and constructs an "asphalt-SBS" transition interface layer to inhibit the phase separation phenomenon, so as to achieve the efficient compound modification of SBS and asphalt under low-speed stirring.

[0006] To solve the technical problems proposed by the present invention, the present invention provides an SBS high-viscosity modified asphalt, which comprises the following raw materials in parts by mass: 77-89 parts of matrix asphalt, 4-9 parts of SBS modifier, 0.1-0.5 part of stabilizer, 5-8 parts of swelling agent, 6-12 parts of compatibilizer, and 0.1-1 part of wax-based auxiliary agent, and the total mass of the raw materials is 100 parts.

[0007] In the above solution, the base asphalt is 70# base asphalt, with a penetration at 25°C of 55 - 65 mm, a softening point of ≥45°C, and a kinematic viscosity at 60°C of >150 Pa·s.

[0008] In the above solution, the SBS modifier is one or more of linear SBS YH - 791H, linear SBS YH - 1401, and star - shaped SBS YH - 813.

[0009] In the above solution, the stabilizer is sulfur.

[0010] In the above solution, the swelling agent is furfural extract oil, with a flash point of 240 - 300°C, an aromatic content of 45 - 55%, and a saturate content of 25 - 30%.

[0011] In the above solution, the compatibilizer is vacuum residue, with a total content of resin and asphaltene of 40 - 50%, an aromatic content of 30 - 40%, a saturate content of 20 - 30%, and also contains a small amount of impurities such as sulfur, nitrogen, and oxygen.

[0012] In the above solution, the wax - based additive is polypropylene wax.

[0013] Preferably, the mass ratio of the SBS modifier, swelling agent, and compatibilizer is 1:(0.6 - 1):(1 - 1.6).

[0014] In the above solution, the penetration of the SBS high - viscosity modified asphalt at 25°C is 55 - 65 mm, the ductility at 5°C is 45 - 55 cm, the softening point is 80 - 120°C, the kinematic viscosity at 60°C is 250000 - 350000 Pa·s, the rotational viscosity at 135°C is 3 - 8 Pa·s, and the Brookfield viscosity at 170°C is 0.4 - 1 Pa·s.

[0015] The present invention also provides a method for preparing SBS high - viscosity modified asphalt, which includes the following steps:

[0016] 1) Heat the base asphalt to a flowing state, add the SBS modifier and a part of the swelling agent, and then conduct primary heat - preservation swelling under stirring conditions;

[0017] 2) Stir and premix the compatibilizer and the remaining swelling agent under heating, then add them to the asphalt after primary swelling, and conduct secondary heat - preservation swelling under stirring conditions;

[0018] 3) Maintain heat - preservation, add the stabilizer to the asphalt after secondary swelling and stir for development, and finally add the wax - based additive and stir evenly to obtain SBS high - viscosity modified asphalt.

[0019] In the above solution, in step 1), the heating temperature of the base asphalt is 140 - 163°C.

[0020] In the above solution, in step 1), the mass ratio of the SBS modifier to the added swelling agent is 1:(0.3 - 0.6).

[0021] In the above solution, in step 2), the mass ratio of the compatibilizer to the remaining swelling agent is 1:(0.2 - 0.4).

[0022] In the above solution, in step 1), the swelling temperature of the primary heat preservation swelling is 140 - 163 °C, the stirring speed is 600 - 1000 rpm, and the swelling time is 1 - 1.5 h.

[0023] In the above solution, in step 2), the heating temperature of the stirring premixing is 140 - 163 °C, the stirring speed is 100 - 300 rpm, and the premixing time is 10 - 30 min.

[0024] In the above solution, in step 2), the swelling temperature of the secondary heat preservation swelling is 163 - 175 °C, the stirring speed is 600 - 1000 rpm, and the swelling time is 30 - 60 min.

[0025] In the above solution, in step 3), the stirring speed after adding the stabilizer is 800 - 1000 rpm, and the development time is 1 - 1.5 h. Using sulfur as the stabilizer, it induces chemical reactions such as cross-linking and grafting between SBS and asphalt, improving the high-temperature storage performance of the modified asphalt. By setting the stirring rate, sulfur is evenly dispersed, and the excessive rotation speed is avoided to damage the three-dimensional network structure of SBS.

[0026] In the above solution, in step 3), the stirring speed after adding the wax-based additive is 800 - 1000 rpm, and the stirring time is 1 - 1.5 h. Using polypropylene wax as the additive, after melting, it can reduce the viscosity of the system, make the swelling agent and compatibilizer more easily dispersed, improve the high-temperature performance of the modified asphalt, and improve the construction fluidity. Introducing polypropylene wax at the end can prevent the premature introduction from affecting the cross-linking reaction, effectively avoid the adverse effects between components, and ensure the integrity of the cross-linking network.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] In view of the problem that traditional SBS modified asphalt requires high-speed shearing, this invention introduces furfural extract oil as a swelling agent and vacuum residue as a compatibilizer. Furfural extract oil is rich in polycyclic aromatic hydrocarbons and trace paraffin components, which can generate strong intermolecular forces with the styrene segments of SBS, promoting the full swelling and stretching of SBS chain segments. However, if too much is added at once, it will cause excessive swelling of SBS and affect the three-dimensional network structure. Therefore, in this invention, it is divided into two parts. First, a part is added to preliminarily swell the SBS particles, and then it is added after mixing with the vacuum residue for secondary swelling. The high content of asphaltene and colloid components in the vacuum residue adsorb on the surface of SBS to construct an "asphalt-SBS" transition interface layer, which can significantly reduce the interfacial energy between the two phases and enhance the high-temperature performance of SBS asphalt. However, when it is added alone, the complexity of its components will lead to unstable performance of the modified asphalt, and a relatively high dosage is required to achieve the expected performance, resulting in cost waste. Therefore, in this invention, it is premixed with the remaining furfural extract oil at high temperature and then added. After mixing, the aromatic fraction and resin act synergistically to effectively improve the swelling and dispersion state of SBS in asphalt, and efficient compound modification of SBS and asphalt can be achieved even under low-speed stirring. Detailed Embodiments

[0029] To better understand this invention, the content of this invention will be further clarified below in conjunction with embodiments. However, the content of this invention is not limited to the following embodiments only.

[0030] In the following embodiments, the base asphalt used is Shell 70# base asphalt, with a penetration at 25°C of 59.5 mm, a softening point of 48.2°C, and a kinematic viscosity at 60°C of 150.84 Pa·s; the furfural extract oil from the third side stream of vacuum distillation is the extract oil obtained after the third side stream of vacuum distillation is treated by the furfural refining process, with a flash point of 243°C, a saturated fraction content of 25.7%, and an aromatic hydrocarbon content of 51.4%; the total content of resin and asphaltene in the vacuum residue used is 40.34%, the saturated fraction content is 27.45%, the aromatic fraction content is 31.89%, and it also contains a small amount of impurities such as sulfur, nitrogen, and oxygen.

[0031] Embodiment 1

[0032] An SBS high-viscosity modified asphalt includes the following raw materials in parts by mass: 78.6 parts of Shell 70# base asphalt, 7.5 parts of SBS modifier (linear SBS YH-791H), 5 parts of furfural extract oil from the third side stream of vacuum distillation, 8 parts of vacuum residue, 0.2 part of sulfur, and 0.7 part of polypropylene wax; the mass ratio of the SBS modifier, furfural extract oil from the third side stream of vacuum distillation, and vacuum residue is 1:0.67:1.07.

[0033] The preparation steps of the SBS high-viscosity modified asphalt in this embodiment are as follows:

[0034] 1) Heat 78.6 parts of matrix asphalt to 163 °C to form a flowing state, add 7.5 parts of SBS modifier and 3 parts of furfural extract oil from the third reduced crude (mass ratio 1:0.4), and keep swelling at 800 rpm for 1 h under stirring conditions;

[0035] 2) Take 10 parts of vacuum residue and the remaining 2 parts of furfural extract oil from the third reduced crude (mass ratio 1:0.2), premix them at 163 °C with stirring at 300 rpm for 20 min, then add them to the asphalt after the first swelling, and keep swelling at 170 °C and 1000 rpm for 30 min under stirring conditions;

[0036] 3) Keep the temperature at 170 °C, add 0.2 part of sulfur to the asphalt after the second swelling, develop it with stirring at 1000 rpm for 1 h, and finally add 0.7 part of polypropylene wax, stir at 1000 rpm for 1 h to obtain SBS high-viscosity modified asphalt.

[0037] Example 2

[0038] An SBS high-viscosity modified asphalt, comprising the following raw materials in parts by mass: 75.6 parts of Shell 70# matrix asphalt, 7.5 parts of SBS modifier (linear SBS YH-791H), 6 parts of furfural extract oil from the third reduced crude, 10 parts of vacuum residue, 0.2 part of sulfur, 0.7 part of polypropylene wax; wherein the mass ratio of the SBS modifier, the furfural extract oil from the third reduced crude and the vacuum residue is 1:0.8:1.33.

[0039] The preparation steps of the SBS high-viscosity modified asphalt in this example are as follows:

[0040] 1) Heat 75.6 parts of matrix asphalt to 140 °C to form a flowing state, add 7.5 parts of SBS modifier and 4 parts of furfural extract oil from the third reduced crude (mass ratio 1:0.53), and keep swelling at 1000 rpm for 1 h under stirring conditions;

[0041] 2) Take 8 parts of vacuum residue and the remaining 2 parts of furfural extract oil from the third reduced crude (mass ratio 1:0.25), premix them at 150 °C with stirring at 200 rpm for 30 min, then add them to the asphalt after the first swelling, and keep swelling at 175 °C and 800 rpm for 40 min under stirring conditions;

[0042] 3) Keep the temperature at 175 °C, add 0.2 part of sulfur to the asphalt after the second swelling, develop it with stirring at 900 rpm for 1 h, and finally add 0.5 part of polypropylene wax, stir at 900 rpm for 1 h to obtain SBS high-viscosity modified asphalt.

[0043] Example 3

[0044] An SBS highly viscous modified asphalt, comprising the following raw materials in parts by mass: 79.85 parts of Shell 70# base asphalt, 6.5 parts of SBS modifier (linear SBS YH-791H), 5 parts of furfural extract oil from the third reduced crude, 8 parts of vacuum residue, 0.15 part of sulfur, and 0.5 part of polypropylene wax; wherein the mass ratio of the SBS modifier, the furfural extract oil from the third reduced crude, and the vacuum residue is 1:0.77:1.23.

[0045] The preparation steps of the SBS highly viscous modified asphalt in this example are as follows:

[0046] 1) Heat 79.85 parts of the base asphalt to 150 °C to form a flowing state, add 6.5 parts of the SBS modifier and 3 parts of the furfural extract oil from the third reduced crude (mass ratio 1:0.46), and keep it swelling at 800 rpm for 1.5 h under stirring conditions;

[0047] 2) Take 8 parts of the vacuum residue and the remaining 2 parts of the furfural extract oil from the third reduced crude (mass ratio 1:0.25), premix them at 140 °C with a stirring speed of 100 rpm for 10 min, and then add them to the asphalt after the first swelling. Keep it swelling at 170 °C and 800 rpm for 50 min under stirring conditions;

[0048] 3) Keep the temperature at 170 °C for heat preservation, add 0.15 part of sulfur to the asphalt after the second swelling, stir and develop it at 1000 rpm for 1.5 h, and finally add 0.5 part of polypropylene wax and stir at 1000 rpm for 1.5 h to obtain the SBS highly viscous modified asphalt.

[0049] Example 4

[0050] An SBS highly viscous modified asphalt, comprising the following raw materials in parts by mass: 72.85 parts of Shell 70# base asphalt, 7.5 parts of SBS modifier (linear SBS YH-791H), 7 parts of furfural extract oil from the third reduced crude, 12 parts of vacuum residue, 0.15 part of sulfur, and 0.5 part of polypropylene wax; wherein the mass ratio of the SBS modifier, the furfural extract oil from the third reduced crude, and the vacuum residue is 1:0.93:1.6.

[0051] The preparation steps of the SBS highly viscous modified asphalt in this example are as follows:

[0052] 1) Heat 72.85 parts of the base asphalt to 163 °C to form a flowing state, add 7.5 parts of the SBS modifier and 4.5 parts of the furfural extract oil from the third reduced crude (mass ratio 1:0.6), and keep it swelling at 1000 rpm for 1.5 h under stirring conditions;

[0053] 2) Take 12 parts of vacuum residue and the remaining 2.5 parts of the furfural extract from the third side stream of vacuum gas oil (mass ratio 1:0.21), stir and premix at 163 °C at a rotation speed of 200 rpm for 30 min, then add it to the asphalt after the first swelling, and keep swelling at 175 °C and under stirring at 800 rpm for 60 min;

[0054] 3) Maintain the temperature at 175 °C, add 0.15 part of sulfur to the asphalt after the second swelling, stir and develop at a rotation speed of 1000 rpm for 1.5 h, and finally add 0.5 part of polypropylene wax, stir at a rotation speed of 800 rpm for 1.5 h to obtain the SBS high-viscosity modified asphalt.

[0055] Comparative Example 1

[0056] The difference between Comparative Example 1 and Example 1 is only that: the furfural extract from the third side stream of vacuum gas oil is not added, and the mass parts of the remaining raw materials remain unchanged; in the preparation method, only the furfural extract from the third side stream of vacuum gas oil is removed, and the remaining operations remain unchanged.

[0057] Comparative Example 2

[0058] The difference between Comparative Example 2 and Example 1 is only that: the vacuum residue is not added, and the mass parts of the remaining raw materials remain unchanged; in the preparation method, only the vacuum residue is removed, and the remaining operations remain unchanged.

[0059] Comparative Example 3

[0060] The difference between Comparative Example 3 and Example 1 is only that: 5 parts of the furfural extract from the third side stream of vacuum gas oil and 8 parts of vacuum residue are adjusted to 4 parts of the furfural extract from the third side stream of vacuum gas oil and 13 parts of vacuum residue, and the mass parts of the remaining raw materials remain unchanged; in the preparation method, it is adjusted to add 2 parts of the furfural extract from the third side stream of vacuum gas oil in step 1) and add 2 parts of the furfural extract from the third side stream of vacuum gas oil in step 2), and the remaining operations remain unchanged.

[0061] Comparative Example 4

[0062] The difference between Comparative Example 4 and Example 1 is only that: all of the furfural extract from the third side stream of vacuum gas oil is added in step 1).

[0063] The performance test results of the asphalts obtained in Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1.

[0064] Table 1 Performance test results of examples and comparative examples

[0065]

[0066] The penetration at 25 °C of the SBS highly viscous modified asphalt prepared in Examples 1 to 4 was 55 to 65 mm, the ductility at 5 °C was 45 to 55 cm, the softening point was 80 to 120 °C, the dynamic viscosity at 60 °C was 250,000 to 350,000 Pa·s, the rotational viscosity at 135 °C was 3 to 8 Pa·s, and the Brookfield viscosity at 170 °C was 0.4 to 1 Pa·s; the "JTG / T 3350-03—2020 Guidelines for the Design and Construction of Porous Asphalt Pavements" requires that the penetration at 25 °C of highly viscous modified asphalt ≥ 40 mm, the ductility at 5 °C ≥ 30 cm, the softening point ≥ 80 °C, the dynamic viscosity at 60 °C ≥ 50,000 Pa·s, and the Brookfield viscosity at 170 °C ≤ 3 Pa·s; the present invention realizes the efficient compound modification of SBS and asphalt under low-speed stirring, and obtains SBS highly viscous modified asphalt with high viscosity and high and low temperature performance, meeting the use requirements of porous asphalt pavements.

[0067] In Comparative Example 1, since only vacuum residue was added and no furfural extract oil from the third side stream of vacuum gas oil was added, the content of aromatics and resins in the vacuum residue was relatively high, which was effective in swelling SBS. During modification under low-speed stirring, it was difficult to penetrate into the interior of SBS molecular chains, resulting in incomplete swelling of SBS, a loose elastic network structure, and a significant decrease in high and low temperature performance, manifested as a significant decrease in softening point, low temperature ductility, penetration, and viscosity, and its performance did not meet the requirements of the "Guidelines for the Design and Construction of Porous Asphalt Pavements".

[0068] In Comparative Example 2, since only furfural extract oil was added and no vacuum residue was added, although it could also improve the performance of SBS modified asphalt and soften SBS modified asphalt, during modification under low-speed stirring, due to insufficient shear force, the swollen SBS could not be evenly dispersed and lacked the plasticization of light components (such as saturates) in the vacuum residue, resulting in poor low temperature brittleness, manifested as a decrease in low temperature ductility, viscosity, and softening point, and an increase in penetration.

[0069] In Comparative Example 3, due to the too large difference in the ratio of furfural extract oil from the third side stream of vacuum gas oil to vacuum residue, the modified asphalt system was unbalanced, which further inhibited the compatibility of SBS and asphalt during modification under low-speed stirring, thus significantly affecting the high and low temperature performance, manifested as a decrease in low temperature ductility, softening point, penetration, and viscosity.

[0070] In Comparative Example 4, since the furfural extract oil from the third side stream of vacuum gas oil was not added step by step and the remaining part was not compounded with the vacuum residue, the furfural extract oil could not completely swell SBS at one time, resulting in uneven dispersion of SBS in the matrix asphalt. During modification under low-speed stirring, due to insufficient shear force, the furfural extract oil and the vacuum residue could not quickly synergize, reducing the compatibility, thus leading to a decrease in the high and low temperature and rheological properties of the modified asphalt, manifested as a decrease in softening point, penetration, viscosity, and low temperature ductility, and its softening point performance also did not meet the requirements of the "Guidelines for the Design and Construction of Porous Asphalt Pavements".

[0071] The above embodiments are merely examples for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or alterations can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here, and thus the obvious changes or alterations derived therefrom still fall within the protection scope of the present invention.

Claims

1. A SBS high viscosity modified asphalt, characterized in that: The invention comprises the following raw materials in parts by weight: 77-89 parts of base asphalt, 4-9 parts of SBS modifier, 0.1-0.5 parts of stabilizer, 5-8 parts of swelling agent, 6-12 parts of compatibilizer, 0.1-1 parts of wax-based additive, and the total weight of the raw materials is 100 parts; the swelling agent is furfural extracted oil, and the compatibilizer is vacuum residue oil.

2. The SBS high-viscosity modified asphalt according to claim 1, characterized in that: The mass ratio of the SBS modifier, the swelling agent and the compatibilizer is 1:(0.6-1):(1-1.6).

3. The SBS high-viscosity modified asphalt according to claim 1, characterized in that: The flash point of the furfural extracted oil is 240-300°C, the aromatic content is 45-55%, and the saturated content is 25-30%; the total content of colloid and asphaltene in the vacuum residue is 40-50%, the aromatic content is 30-40%, and the saturated content is 20-30%.

4. The SBS high-viscosity modified asphalt according to claim 1, characterized in that: The base asphalt is 70# base asphalt, with a needle penetration of 55-65mm at 25°C, a softening point of ≥45°C, and a dynamic viscosity of >150Pa·s at 60°C; the SBS modifier is one or more of linear SBS YH-791H, linear SBS YH-1401, and star-shaped SBS YH-813; the stabilizer is sulfur; and the wax-based additive is polypropylene wax.

5. The SBS high-viscosity modified asphalt according to claim 1, characterized in that: The SBS high-viscosity modified asphalt has a needle penetration of 55-65 mm at 25°C, an elongation of 45-55 cm at 5°C, a softening point of 80-120°C, a dynamic viscosity of 250,000-350,000 Pa·s at 60°C, a rotational viscosity of 3-8 Pa·s at 135°C, and a Brookfield viscosity of 0.4-1 Pa·s at 170°C.

6. A method for preparing the SBS high-viscosity modified asphalt according to any one of claims 1 to 5, characterized in that: The following steps are involved: 1) Heat the base asphalt to a fluid state, add the SBS modifier and a portion of the swelling agent, and then perform a heat preservation swelling process under stirring conditions; 2) After the compatibilizer and the remaining swelling agent are premixed under stirring in a heated state, they are added to the asphalt after the primary swelling, and a secondary thermal insulation swelling is performed under stirring conditions; 3) Maintaining heat preservation, adding stabilizer to the asphalt after secondary swelling to stir and develop, and finally adding wax-based additives to stir evenly to obtain SBS high-viscosity modified asphalt.

7. The method for preparing SBS high-viscosity modified asphalt according to claim 6, characterized in that: In step 1), the mass ratio of the SBS modifier to the added swelling agent is 1:(0.3-0.6); in step 2), the mass ratio of the compatibilizer to the remaining swelling agent is 1:(0.2-0.4).

8. The method for preparing SBS high-viscosity modified asphalt according to claim 6, characterized in that: In step 1), the heating temperature of the base asphalt is 140-163° C., the swelling temperature of the primary thermal insulation swelling is 140-163° C., the stirring speed is 600-1000 rpm, and the swelling time is 1-1.5 h.

9. The method for preparing SBS high-viscosity modified asphalt according to claim 6, characterized in that: In step 2), the heating temperature of the stirring premixing is 140-163° C., the stirring speed is 100-300 rpm, and the premixing time is 10-30 min; the swelling temperature of the secondary thermal insulation swelling is 163-175° C., the stirring speed is 600-1000 rpm, and the swelling time is 30-60 min.

10. The method for preparing SBS high-viscosity modified asphalt according to claim 6, characterized in that: In step 3), the stirring speed after the stabilizer is added is 800-1000 rpm, and the development time is 1-1.5 h; the stirring speed after the wax-based additive is added is 800-1000 rpm, and the stirring time is 1-1.5 h.

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