Soluble SBS modified asphalt and preparation method thereof

Abstract

The invention discloses soluble SBS modified asphalt and a preparation method thereof, and belongs to the technical field of asphalt processing. The preparation method comprises the following steps: (1) pre-expanding SBS particles in a composite dispersant to prepare a pre-swelling easily-soluble SBS modifier; and (2) mixing and stirring the pre-swelling easily-soluble SBS modifier obtained in the step (1), sulfur powder and asphalt, and then standing and developing to obtain the asphalt. According to the invention, the SBS particles are modified by the composite dispersant, so that the low-temperature crack resistance of the modified asphalt is effectively improved; the high-temperature performance of the modified asphalt is effectively improved by doping sulfur; according to the present invention, with the composite dispersant, the asphalt oxidation delaying effect, the pre-swelling easily-soluble SBS modifier doping, the sulfur doping and the simple stirring effect of the modifier in the asphalt, the aging and the segregation caused by the long-time high-temperature heating development and storage of the traditional SBS modified asphalt are avoided, and the performance of the modified asphalt is comprehensively improved;

Description

Technical Field

[0001] The invention relates to the technical field of asphalt processing, and in particular to a soluble SBS modified asphalt and a preparation method thereof. Background Art

[0002] With the continuous development of social economy, due to the rapid increase in traffic volume on ordinary roads and highways, complex environmental changes and other comprehensive factors, conventional asphalt materials can no longer meet the needs of long-life pavement, which greatly increases the frequency of road maintenance and road reconstruction. Therefore, in order to improve the performance of asphalt materials, meet the needs of pavement durability and the adhesion between asphalt materials and mineral aggregates, people have long pursued and studied asphalt binders with high elastic response and hardness, so that asphalt pavements can maintain good cracking resistance at low temperatures and avoid permanent deformation at high temperatures. Polymer modified asphalt (PMA) technology came into being.

[0003] Common polymers currently used to modify asphalt are divided into three categories according to their properties: thermoplastic elastomers (TPE), plastic polymers and reactive polymers. Among them, styrene-butadiene-styrene (SBS) copolymers of the TPE class are the preferred and most widely used polymers. SBS is an elastic polymer additive composed of glassy polystyrene (PS) domains connected by polybutadiene (PB) segments, presenting a two-phase morphology. After SBS is added to asphalt, the PB blocks absorb formaldehyde (aromatics and saturated) and expand to 9-10 times the original volume, while the PS blocks are expanded by aromatics, which improves the asphalt's crack resistance at low temperatures and rutting resistance at high temperatures. Therefore, it is widely used in the production of modified asphalt.

[0004] However, SBS modified asphalt is usually prepared by the traditional high-speed mixing and shearing process (wet method). In the actual high-speed mixing and shearing process, the high modification processing temperature brings about greater energy consumption and also accelerates the thermal oxidation aging phenomenon of the modified asphalt. In addition, SBS modified asphalt only shows physical mixing, and there is no obvious chemical reaction, which shows that the actual connection between SBS and asphalt is very weak; on the other hand, SBS and original asphalt have differences in density, solubility, polarity and relative molecular mass. Even the prepared SBS modified asphalt is still prone to phase separation during storage, transportation and construction. Phase separation deteriorates the performance of the modified asphalt and cannot give full play to the advantages of the modified asphalt. Therefore, the problems of thermal oxidation aging of asphalt caused by defects in the processing technology of traditional SBS modified asphalt and poor storage stability of SBS modified asphalt caused by poor compatibility between SBS and asphalt are still the key shortcomings that hinder its full performance. Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a soluble SBS modified asphalt and a preparation method thereof, so as to solve the problems of the existing traditional SBS modified asphalt such as asphalt thermal oxidation aging, poor storage stability caused by poor compatibility, etc.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] A method for preparing soluble SBS modified asphalt comprises the following steps:

[0008] (1) Pre-swelling the SBS particles in a composite dispersant to obtain a pre-swelled and easily soluble SBS modifier;

[0009] (2) mixing and stirring the pre-swollen soluble SBS modifier obtained in step (1), sulfur powder and asphalt, and then letting them stand to grow, to obtain;

[0010] The composite dispersant comprises the following components in percentage by mass: 10-15% of aromatic oil, 10-15% of extracted oil, 20-30% of surfactant and 40-60% of base asphalt.

[0011] The beneficial effects of the present invention are as follows: the present invention modifies SBS particles by a composite dispersant, and then mixes and stirs the mixture with sulfur powder and asphalt, and then allows the mixture to stand for development to successfully obtain soluble SBS modified asphalt. The preparation method is simple, and the obtained soluble SBS modified asphalt has excellent anti-aging performance, high-temperature anti-rutting performance, and low-temperature anti-cracking performance.

[0012] Preferably, the composite dispersant comprises the following components in percentage by mass: 15% aromatic oil, 15% extracted oil, 20% surfactant and 50% base asphalt.

[0013] Furthermore, in step (1), the mass ratio of the SBS particles to the composite dispersant is 1:0.7-1:1.1.

[0014] Preferably, in step (1), the mass ratio of SBS particles to composite dispersant is 1:0.8.

[0015] Furthermore, the pre-expansion temperature in step (1) is 60-80° C. and the time is 60-80 h.

[0016] Preferably, the pre-expansion temperature in step (1) is 80° C. and the pre-expansion time is 72 h.

[0017] Furthermore, during the pre-expansion, stirring is performed at 10-30 min, 50-70 min, 2.5-3.5 h, 4-6 h, 10-15 h, 20-30 h, 55-65 h and 70-80 h, with the stirring time being 5-20 min and the rotation speed being 500-1200 rpm.

[0018] Preferably, during the pre-expansion, stirring is performed at 20 min, 1 h, 3 h, 5 h, 12 h, 24 h, 60 h and 72 h, with the stirring time being 10 min and the rotation speed being 800 rpm.

[0019] The effects of adopting the above further technical scheme are as follows: the present invention prepares soluble SBS modified asphalt by pre-expanding it in a composite dispersant to perform soluble modification, and obtains the best modification conditions and mass ratio by optimizing the mass ratio of the composite dispersant and SBS particles and the modification conditions, and improves the anti-aging and low-temperature crack resistance of the asphalt through the oxidation retarding effect of the composite dispersant on the asphalt, and further improves the anti-aging performance of the asphalt through the addition of the pre-swelling soluble SBS modifier.

[0020] Furthermore, in step (2), the mass of the pre-swollen soluble SBS modifier is 3-5% of the mass of the asphalt; the mass of the sulfur powder is 1-7% of the mass of the pre-swollen soluble SBS modifier; and the particle size of the sulfur powder is 75-150 μm.

[0021] Preferably, in step (2), the mass of the pre-swollen and soluble SBS modifier is 4% of the mass of the asphalt; the mass of the sulfur powder is 3% of the mass of the pre-swollen and soluble SBS modifier.

[0022] The beneficial effect of adopting the above further technical solution is that the present invention effectively improves the high temperature performance of the soluble SBS modified asphalt by adding sulfur, and avoids the negative impact of the presence of aromatic oil in the composite dispersant on the high temperature performance of the modified asphalt.

[0023] Furthermore, in step (2), the mixing and stirring temperature is 130-160° C., the stirring speed is 800-1200 rpm, and the time is 0.5-2 h.

[0024] Preferably, the mixing and stirring in step (2) is carried out at 140° C., with a stirring speed of 1000 rpm and a time of 1.0 h.

[0025] Furthermore, in step (2), the temperature for static development is 130-160° C., and the time is 0.5-2 h.

[0026] Preferably, the temperature for static development in step (2) is 140° C. and the time is 1.0 h.

[0027] The beneficial effect of adopting the above further technical solution is that the present invention reduces the mixing temperature and the standing development temperature in the traditional SBS modified asphalt processing technology by optimizing the mixing temperature and time and the standing development temperature and time.

[0028] A soluble SBS modified asphalt is prepared by adopting the preparation method.

[0029] The application of the above soluble SBS modified asphalt in the preparation of road paving materials.

[0030] The present invention has the following beneficial effects:

[0031] The invention provides a preparation method of soluble SBS modified asphalt, wherein SBS particles are modified by a composite dispersant, thereby effectively improving the low-temperature crack resistance of the modified asphalt; the high-temperature performance of the modified asphalt is effectively improved by adding sulfur; the anti-aging performance of the modified asphalt is comprehensively improved by the delayed oxidation of the asphalt by the composite dispersant, the addition of a pre-swelling soluble SBS modifier and the addition of sulfur. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The curves of G* and δ of different asphalt samples in Test Example 3 with temperature, where a is the base asphalt, b is the comparative example 1, c is the comparative example 2, d is the embodiment 1, e is the comparative example 3, and f is the comparative example 4;

[0033] Figure 2 The G* / sinδ curves of different asphalt samples in Test Example 3 are as a function of temperature, wherein a is the base asphalt, b is Comparative Example 1, c is Comparative Example 2, d is Example 1, e is Comparative Example 3, and f is Comparative Example 4. DETAILED DESCRIPTION

[0034] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples are only used to explain the present invention and are not used to limit the scope of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0035] Embodiment 1:

[0036] A method for preparing soluble SBS modified asphalt comprises the following steps:

[0037] (1) SBS particles (Hunan Yueyang Baling Petrochemical Company, YH-792 linear molecular structure SBS particles, S / B ratio of 40 / 60) were added to a container, shaken and squeezed appropriately to reduce the gaps, and then a composite dispersant was added. The mass ratio of SBS particles to composite dispersant was 1:0.8. The composite dispersant included the following components in mass percentage: aromatic oil (Shandong Qilu Petrochemical Company, S1000# aromatic oil) 15%, extracted oil (Hengshui Aoda Chemical Rubber Co., Ltd.) 15%, surfactant (Shandong Jinli Chemical Co., Ltd.) 20% and base asphalt (A-70) 50%. ; Press the SBS particles to make them completely immersed in the composite dispersant and seal them; then place them in an 80°C incubator to make them expand evenly, and stir them at 20 minutes, 1 hour, 3 hours, 5 hours, 12 hours, 24 hours, 48 ​​hours, 60 hours and 72 hours, with a stirring time of 10 minutes and a rotation speed of 800 rpm to obtain a pre-swollen and easily soluble SBS modifier.

[0038] (2) The pre-swollen and soluble SBS modifier obtained in step (1), sulfur powder (Shandong Linyi Houpu Chemical Co., Ltd., particle size of 75-150 μm) and base asphalt (Shandong Jingbo Petrochemical Co., Ltd., A-90 base asphalt) are mixed, wherein the pre-swollen and soluble SBS modifier is added in an amount of 4% by mass of the base asphalt, and the sulfur powder is added in an amount of 3% by mass of the pre-swollen and soluble SBS modifier; after mixing, the mixture is stirred at 140° C. and 1000 rpm for 0.5 h; and then allowed to stand at 140° C. for 1 h to obtain the product.

[0039] Embodiment 2:

[0040] A method for preparing soluble SBS modified asphalt comprises the following steps:

[0041] The preparation method is the same as that of Example 1, except that the mass ratio of SBS particles to composite dispersant in step (1) is changed to 1:0.7.

[0042] Embodiment 3:

[0043] A method for preparing soluble SBS modified asphalt comprises the following steps:

[0044] The preparation method is the same as that of Example 1, except that the mass ratio of SBS particles to composite dispersant in step (1) is changed to 1:0.9.

[0045] Embodiment 4:

[0046] A method for preparing soluble SBS modified asphalt comprises the following steps:

[0047] The preparation method is the same as that of Example 1, except that the mass ratio of SBS particles to composite dispersant in step (1) is changed to 1:1.0.

[0048] Embodiment 5:

[0049] A method for preparing soluble SBS modified asphalt comprises the following steps:

[0050] The preparation method is the same as that of Example 1, except that the mass ratio of SBS particles to composite dispersant in step (1) is changed to 1:1.1.

[0051] Embodiment 6:

[0052] A method for preparing soluble SBS modified asphalt comprises the following steps:

[0053] The preparation method is the same as that of Example 1, except that the amount of pre-swollen soluble SBS modifier added in step (2) is changed to 3% of the mass of the base asphalt.

[0054] Embodiment 7:

[0055] A method for preparing soluble SBS modified asphalt comprises the following steps:

[0056] The preparation method is the same as that of Example 1, except that the amount of pre-swollen soluble SBS modifier added in step (2) is changed to 5% of the mass of the base asphalt.

[0057] Embodiment 8:

[0058] A method for preparing soluble SBS modified asphalt comprises the following steps:

[0059] The preparation method is the same as that of Example 1, except that the amount of sulfur powder added in step (2) is changed to 1% of the mass of the pre-swelling soluble SBS modifier.

[0060] Embodiment 9:

[0061] A method for preparing soluble SBS modified asphalt comprises the following steps:

[0062] The preparation method is the same as that of Example 1, except that the amount of sulfur powder added in step (2) is changed to 5% of the mass of the pre-swelling soluble SBS modifier.

[0063] Embodiment 10:

[0064] A method for preparing soluble SBS modified asphalt comprises the following steps:

[0065] The preparation method is the same as that of Example 1, except that the amount of sulfur powder added in step (2) is changed to 7% of the mass of the pre-swelling soluble SBS modifier.

[0066] Comparative Example 1

[0067] A method for preparing soluble SBS modified asphalt comprises the following steps:

[0068] (1) SBS particles were added into a container, shaken and squeezed appropriately to reduce the voids, and then aromatic oil was added, the mass ratio of SBS particles to aromatic oil (Shandong Qilu Petrochemical Company, S1000# aromatic oil) 25% was 1:0.8; the SBS particles were pressed to make them completely immersed in the aromatic oil and sealed; then they were placed in an 80°C incubator to make them expand evenly, and stirred at 20 minutes, 1 hour, 3 hours, 5 hours, 12 hours, 24 hours, 48 ​​hours, 60 hours and 72 hours, the stirring time was 10 minutes, and the rotation speed was 800 rpm, to obtain a pre-swelling soluble SBS modifier.

[0069] (2) The pre-swollen and soluble SBS modifier obtained in step (1) is mixed with base asphalt, wherein the amount of the pre-swollen and soluble SBS modifier added is 4% of the mass of the base asphalt; after mixing, the mixture is stirred at 140° C. and 1000 rpm for 1 hour; and then allowed to stand and develop at 140° C. for 1 hour to obtain the product.

[0070] Comparative Example 2:

[0071] A method for preparing soluble SBS modified asphalt comprises the following steps:

[0072] The preparation method is the same as that of Comparative Example 1, except that the amount of pre-swollen soluble SBS modifier added in step (2) is changed to 5% of the mass of the base asphalt.

[0073] Comparative Example 3:

[0074] A method for preparing soluble SBS modified asphalt comprises the following steps:

[0075] The preparation method is the same as that of Comparative Example 1, except that the mass ratio of SBS particles to aromatic oil is changed to 1:0.9.

[0076] Comparative Example 4:

[0077] A method for preparing a conventional SBS modified asphalt comprises the following steps:

[0078] Take base asphalt at 170°C, add SBS particles and stir with a glass rod for 10 minutes, then place in an oil bath at 180°C and perform high-speed shearing with a shear rate of 5000rpm for 60 minutes; after the shearing is completed, continue to stir at a rate of 250rpm in the 180°C oil bath for 60 minutes, and after the stirring is completed, place in an oven at 180°C for 60 minutes to obtain the product.

[0079] Test Example 1: Effect of sulfur content on modified asphalt performance

[0080] The soluble SBS modified asphalt obtained in Example 1, Examples 8-10 and Comparative Example 1 was tested to test the needle penetration at 25°C, softening point, elongation at 5°C and elastic recovery index at 25°C of each sample. The specific test operation was carried out in accordance with the specification (JTG 320-2011).

[0081] The test results are shown in Table 1.

[0082] Table 1 Effect of sulfur content on modified asphalt performance

[0083]

[0084] According to the data in the above table:

[0085] (1) The softening point of modified asphalt increases with the increase of sulfur addition. When the addition amount is 1% (i.e., Example 8), the softening point of modified asphalt is improved but the effect is not significant enough. When the addition amount exceeds 5%, the softening point decreases instead. The results show that the appropriate sulfur addition amount can effectively improve the high temperature performance of soluble SBS modified asphalt.

[0086] (2) With the increase of sulfur addition, the penetration of soluble SBS modified asphalt gradually decreases. According to the data changes, it can be seen that when the sulfur addition increases from 1% to 3%, it has a greater impact on the penetration of modified asphalt. Subsequently, with the increase of sulfur addition, the rate of decrease of its penetration gradually tends to be flat.

[0087] (3) The ductility of the modified asphalt decreases with the increase of the amount of sulfur added, which is opposite to the change trend of the softening point. When the sulfur doping amount is 1-5%, the modified asphalt has a higher ductility. When it exceeds 5%, the ductility of the modified asphalt will decrease. This shows that while the addition of sulfur improves the high-temperature performance of the modified asphalt, it will also reduce its low-temperature performance. The amount of sulfur added should not be too large or too small.

[0088] (4) The viscosity of the modified asphalt at 135°C increases with the increase in the amount of sulfur added. The greater the amount of sulfur added, the faster the viscosity growth trend of the modified asphalt. At the same time, the above results also show that the modified asphalt obtained in the embodiments of the present invention has a stronger anti-deformation ability provided by sulfurization, but the amount of sulfur added should not be too large. When the viscosity is too large, the fluidity of the modified asphalt is reduced, which can easily cause construction difficulties.

[0089] (5) The elastic recovery rate of modified asphalt first increases and then decreases with the increase of sulfur addition, indicating that sulfur can effectively improve the elastic properties of modified asphalt. However, when the sulfur addition amount is too large, it will cause the SBS particles in the modified asphalt to gel. The excessive cohesive force makes it difficult for the modified asphalt to recover when it is deformed by force, resulting in a decrease in the elastic recovery rate.

[0090] (6) The 48h softening point difference of modified asphalt shows a trend of first decreasing and then increasing with the increase of sulfur addition, indicating that an appropriate amount of sulfur can effectively improve the storage stability of soluble SBS modified asphalt, but when the sulfur addition amount is too high, its storage stability will be reduced, which is consistent with other data.

[0091] In summary, the present invention can effectively improve the high temperature performance, ductility, viscosity, elastic recovery rate and storage stability of the modified asphalt by adding sulfur, but the addition amount should not be too high, and the optimal addition amount is 3-5%. Example 1 is the best embodiment of the present invention.

[0092] Test Example 2: Aging Performance Analysis

[0093] (1) Rotating Thin Film Oven Aging Test (RTFOT)

[0094] The base asphalt, Example 1, Comparative Examples 1-2 and Comparative Example 4 were tested. The short-term aging of asphalt was simulated by performing a rotary thin film oven aging test. The mass change before and after aging, the needle penetration ratio and the softening point increment were used to characterize the short-term aging resistance of the asphalt. The specific test operation was carried out in accordance with the specification (JTG E20-2011).

[0095] The test results are shown in Table 2.

[0096] Table 2 RTFOT indicators of different types of asphalt before and after

[0097]

[0098]

[0099] According to the data in the above table, the change of the base asphalt before and after aging is the largest, indicating that the addition of either pre-swelling soluble SBS or SBS particles will improve the aging performance of the modified asphalt. According to the performance comparison of the modified asphalt obtained by the examples and comparative examples of the present application, the modified asphalt obtained by Example 1 of the present invention has the lowest softening point increment, the lowest mass loss rate and the highest penetration ratio. The results show that the present invention not only improves the anti-aging performance of asphalt by incorporating pre-swelling soluble SBS, but also further improves the anti-aging performance of the modified asphalt by incorporating sulfur, and improves the high temperature performance of the modified asphalt. At the same time, the composite dispersant plays a role in supplementing the light components of the asphalt during the aging process of the modified asphalt. Compared with the comparative example in which only aromatic oil is added, the examples of the present invention comprehensively improve the anti-aging performance of the modified asphalt.

[0100] (2) Pressure aging (PAV)

[0101] The PAV test was carried out on the base asphalt, the modified asphalt prepared in Examples 1-4, Comparative Examples 1-2 and Comparative Example 4 using a pressure aging tester. The test conditions were 100°C and 20 hours. The long-term aging performance of the asphalt was characterized by the mass change before and after aging, the needle penetration ratio and the softening point increment.

[0102] The test results are shown in Table 3.

[0103] Table 3 Indexes of different types of asphalt before and after PAV

[0104]

[0105] According to the data in the above table, relative to the base asphalt, the various indicators of the modified asphalts in other groups have a small change range with the extension of the aging time, indicating that the several treatment methods have a good modification effect on the anti-aging performance of the asphalt. The modified asphalt prepared in Example 1 of the present invention has the lowest mass loss, the highest penetration ratio and the lowest softening point value-added relative to other comparative examples, and has a significant improvement in anti-aging performance relative to other comparative example groups. The main reason is that sulfur promotes the SBS particles to form a stable network structure, making the SBS particles difficult to degrade, and the composite dispersant has a favorable effect on the performance of the modified asphalt during the aging process, delaying the oxidation of the asphalt and promoting the improvement of the anti-aging performance of the modified asphalt.

[0106] Test Example 3: Dynamic Shear Rheology Test (DSR)

[0107] (1) Temperature scanning test

[0108] The dynamic shear rheometer was used in strain frame mode, with 25 mm parallel plates, a parallel plate spacing of 1 mm, a fixed shear strain of 12%, a constant frequency of 10 rad / s, and a test temperature range of 40-90°C (every 10°C).

[0109] Through the temperature scanning test, the two major parameters of the complex shear modulus (G*) and phase angle (δ) of the asphalt under different temperature conditions can be obtained. The modified asphalt prepared in Example 1 and Comparative Examples 1-4 was subjected to a temperature scanning test and compared with the base asphalt and the traditional SBS modified asphalt to comprehensively evaluate the high temperature stability of the modified asphalt prepared by the new modification process.

[0110] The test results are as follows Figure 1 and Figure 2 shown.

[0111] according to Figure 1The test results in show that the complex shear modulus of all asphalts gradually decreases with the rise of temperature, and the final area is gentle, which shows that as the temperature rises, the elastic component of asphalt decreases, and the viscous component increases, resulting in a decrease in its anti-deformation ability. With matrix asphalt as the control group, it can be seen that the addition of the pre-swelling soluble SBS modifier has an obvious modification effect, which greatly improves the anti-deformation ability of asphalt. However, by comparing the complex shear modulus between comparative examples 1-4, it is known that the addition of aromatic oil or the increase in content has an adverse effect on the high-temperature anti-deformation ability of asphalt. According to the change trend of the phase angle with temperature and the platform area width comparison of comparative examples 1-4, it can also be proved from the side that aromatic oil has an adverse effect on the high-temperature performance of asphalt. And the modified asphalt obtained in Example 1 of the present invention increases the viscous component of asphalt by mixing sulfur, and adopts a non-single aromatic oil but a composite dispersant mode, further enhancing the anti-rutting resistance of asphalt, relative to the modified asphalt obtained in comparative examples 1-4, the modified asphalt obtained in Example 1 of the present invention has a significant improvement in high-temperature performance.

[0112] according to Figure 2 From the test results, it can be seen that the change trends of G* / sinδ and G* of all asphalts are basically the same, and the high temperature performance of all modified asphalts is greatly improved compared with the base asphalt. The high temperature performance of the modified asphalt prepared in Example 1 of the present invention is significantly higher than that of Comparative Examples 1-3. The results show that the high temperature stability of the modified asphalt can be effectively improved by the method of co-incorporating the pre-swelling soluble SBS modifier and sulfur in the present invention, and the addition of sulfur has a greater impact on the high temperature performance, and even the high temperature performance is better than that of Comparative Example 4 within a certain temperature range.

[0113] (2) Multiple stress creep recovery test (MSCR)

[0114] According to the RTFOT conditions in Test Example 2, the base asphalt, the modified asphalt obtained in Example 1 and Comparative Examples 1-4 were subjected to RTFOT and then MSCR test was performed by DSR instrument. In the rotation mode at 64°C, 70°C and 76°C, each cyclic stress was applied for 1s and stopped for 9s, and then the shear strain of the asphalt would recover within 9s. 10 creep and recovery cycles were performed under 0.1kPa creep stress to simulate the deformation of asphalt under light traffic loads; then 10 creep and recovery cycles were performed under 3.2kPa creep stress to simulate the deformation of asphalt under heavy traffic loads.

[0115] The test results of the recovery rate of each asphalt under different stresses and temperatures are shown in Table 4.

[0116] Table 4 Recovery rate of various asphalts at different stresses and temperatures

[0117]

[0118] According to the test results in the above table, the recovery rate of the base asphalt is much smaller than that of the modified asphalt, indicating that the modified asphalt has good elastic recovery ability, so that the asphalt can still maintain good elastic properties under high temperature and high stress environment. The higher the recovery rate, the better the elasticity of the asphalt, and the stronger the ability to recover deformation after being subjected to stress. By comparing the modified asphalt obtained in Example 1 and Comparative Examples 1-4, it can be seen that the addition of aromatic oil or the increase in content will have a negative impact on the elastic properties of asphalt, and Example 1 in this application further improves the elastic recovery ability of the soluble SBS modified asphalt by adding sulfur and using a composite dispersant rather than a single aromatic oil for modification.

[0119] The test results of irreversible creep compliance of various asphalts under different stresses and temperatures are shown in Table 5.

[0120] Table 5 Irrecoverable creep compliance of various asphalts at different stresses and temperatures

[0121]

[0122] According to the test results in Table 5 above, consistent with the above-mentioned asphalt recovery rate test results, the base asphalt has a large part that cannot be recovered after creep, while other modified asphalts show a good elastic recovery ability. By comparing the modified asphalts obtained in Example 1 and Comparative Examples 1-4, it can be seen that the addition or increase in the content of aromatic oil will have a negative impact on the elastic properties of asphalt, and excessive aromatic oil will damage the temperature and pressure stability of asphalt, thereby reducing its rutting resistance, while the combination of SBS particles and sulfur and the use of a composite dispersant together provide the modified asphalt with better elastic properties and resistance to permanent deformation.

[0123] The stress sensitivity test results of each asphalt at different temperatures are shown in Table 6.

[0124] Table 6 Stress sensitivity of various asphalts at different temperatures

[0125]

[0126]

[0127] According to the test results in Table 6 above, the stress sensitivity of all modified asphalts increases with the increase of temperature, indicating that the sensitivity of modified asphalt to stress changes increases under high temperature conditions. By comparing the modified asphalts obtained in Example 1 and Comparative Examples 1-4, it can be seen that the addition or increase in the content of aromatic oil will significantly increase the stress sensitivity of asphalt, which is not conducive to the high temperature performance of modified asphalt. The modified asphalt prepared in Example 1 of the present invention significantly reduces the stress sensitivity by combining SBS particles with sulfur and using a composite dispersant, thereby improving the high temperature performance of modified asphalt.

[0128] Test Example 4: Low Temperature Bending Beam Rheology (BBR) Test

[0129] The base asphalt, the modified asphalt obtained in Example 1, Comparative Examples 1-2 and Comparative Example 4 were subjected to low temperature rheological bending beam tests by a bending beam creep instrument. After the modified asphalt was subjected to PAV aging according to the method in Test Example 2, the aged samples were subjected to a BBR comparative test, and -12°C, -18°C and -24°C were selected as the test conditions.

[0130] The test results are shown in Table 7.

[0131] Table 7 Test results of different types of modified asphalt BBR

[0132]

[0133] According to the data in Table 7 above, in all types of asphalt, the trend of creep stiffness increasing faster with lower temperature is shown. The modified asphalt prepared in Example 1 of the present invention significantly reduces the stiffness of the modified asphalt under low temperature conditions by adding a composite dispersant to the components, effectively improving the low temperature crack resistance of the modified asphalt, while the addition of sulfur only slightly reduces the low temperature crack resistance of the modified asphalt, but is still significantly higher than the traditional SBS modified asphalt comparative example 4. The stress dissipation capacity shows a trend of decreasing stress dissipation capacity with lower temperature, which is opposite to the trend of creep stiffness; the presence of the same composite dispersant significantly improves the stress dissipation capacity of the soluble SBS modified asphalt, while the addition of sulfur makes the stress dissipation capacity of the soluble SBS modified asphalt at low temperature slightly worse, but is still significantly better than the traditional SBS modified asphalt comparative example 4.

[0134] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing soluble SBS modified asphalt, characterized in that: The following steps are involved: (1) Pre-swelling the SBS particles in a composite dispersant to obtain a pre-swelled and easily soluble SBS modifier; (2) mixing and stirring the pre-swollen soluble SBS modifier obtained in step (1), sulfur powder and asphalt, and then letting them stand to grow, to obtain; The composite dispersant comprises the following components in percentage by mass: 10-15% of aromatic oil, 10-15% of extracted oil, 20-30% of surfactant and 40-60% of base asphalt.

2. The method for preparing soluble SBS modified asphalt according to claim 1, characterized in that: In the step (1), the mass ratio of the SBS particles to the composite dispersant is 1:0.7-1:1.

1.

3. The method for preparing soluble SBS modified asphalt according to claim 1, characterized in that: The pre-expansion temperature in step (1) is 60-80°C and the time is 60-80h.

4. The method for preparing soluble SBS modified asphalt according to claim 3, characterized in that: During pre-expansion, stirring is performed at 10-30 min, 50-70 min, 2.5-3.5 h, 4-6 h, 10-15 h, 20-30 h, 55-65 h and 70-80 h, with the stirring time being 5-20 min and the rotation speed being 500-1200 rpm.

5. The method for preparing soluble SBS modified asphalt according to claim 1, characterized in that: In the step (2), the mass of the pre-swelled soluble SBS modifier is 3-5% of the mass of the asphalt; the mass of the sulfur powder is 1-7% of the mass of the pre-swelled soluble SBS modifier; and the particle size of the sulfur powder is 75-150 μm.

6. The method for preparing soluble SBS modified asphalt according to claim 1, characterized in that: The mixing and stirring in step (2) is carried out at a temperature of 130-160° C., a stirring speed of 800-1200 rpm, and a time of 0.5-2 h.

7. The method for preparing soluble SBS modified asphalt according to claim 1, characterized in that: The temperature of the static development in step (2) is 130-160° C. and the time is 0.5-2 h.

8. A soluble SBS modified asphalt, characterized in that: The method is prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the soluble SBS modified asphalt according to claim 8 in preparing road paving materials.

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