High-elasticity modified asphalt, modified asphalt mixture, and preparation method and application thereof

Abstract

The application discloses high-elasticity modified asphalt, modified asphalt mixture, and a preparation method and application thereof. The high-elasticity modified asphalt comprises the following components in parts by weight: 70-88 parts of base asphalt, 10-16 parts of SBS, 2-4 parts of butyronitrile rubber, 8-16 parts of naphthenic oil, 1-3 parts of RET modifier, and 0.3-0.6 parts of anti-stripping agent. The modified asphalt mixture prepared from the high-elasticity modified asphalt has good fatigue resistance and deformation following capacity, and is suitable for steel bridge deck pavement.

Description

Technical Field

[0001] This invention relates to a highly elastic modified asphalt, a modified asphalt mixture, its preparation method, and its application. Background Technology

[0002] With rapid development in recent years, long-span bridges are becoming increasingly common. To reduce the weight of these bridges, most of them use steel decks. Steel deck paving is one of the key aspects of steel bridge construction. Compared with general highway asphalt concrete pavement, steel bridge deck pavement has the following characteristics: (1) Asphalt mixture is directly laid on steel bridge deck. The deformation, displacement, vibration and other factors of the steel bridge deck itself directly affect the working state of the pavement layer. The maximum tensile stress or tensile strain of the asphalt mixture pavement layer on the steel bridge deck appears on the surface of the pavement layer. Fatigue cracks extend from the surface of the pavement layer to the bottom, which is the opposite of general asphalt concrete pavement; (2) The thermal conductivity of steel bridge deck is much greater than that of other geotechnical materials. Asphalt mixture pavement is more susceptible to the influence of atmospheric temperature. Its surface high temperature value and low temperature value are much greater than those of general asphalt concrete pavement; (3) Steel bridges are subject to the vibration caused by strong winds and other factors; (4) Once the bridge deck pavement is damaged, the impact on traffic is much greater than the impact and harm caused by the damage to the highway pavement, and maintenance is more difficult; (5) Steel rusts when exposed to water, requiring good pavement density. Therefore, in addition to meeting the general requirements for road performance, asphalt mixture paving for steel bridge decks must also have better high and low temperature performance and aging resistance, good adhesion to the steel bridge deck, waterproof and corrosion resistant properties for the steel bridge deck, and fatigue resistance to adapt to local bending deformation of stiffened girder bridge decks.

[0003] Currently, there are three main types of steel bridge deck paving materials worldwide: epoxy asphalt mixtures, cast-in-place asphalt concrete, and stone mastic asphalt (SMA) mixtures. Epoxy asphalt mixtures possess high strength, excellent fatigue resistance, good durability, and anti-aging properties; however, their high cost, demanding construction requirements, and difficulty in repair after damage limit their widespread application. Cast-in-place asphalt concrete exhibits good water tightness and high steel plate deformation tracking ability, but suffers from poor high-temperature stability and insufficient rutting resistance. Existing SMA mixtures, as steel bridge deck paving materials, offer good high-temperature stability, durability, and waterproofing, but their main shortcomings are poor fatigue resistance and deformation tracking ability. To meet the requirements of steel bridge deck paving, domestic and international scholars have conducted formulation research on modified asphalt, but effective solutions have yet to be found. Summary of the Invention

[0004] This invention aims to overcome the shortcomings of existing steel bridge deck pavement materials in terms of poor fatigue resistance and deformation following ability, by providing a highly elastic modified asphalt, a modified asphalt mixture, its preparation method, and its application. The modified asphalt mixture prepared using the highly elastic modified asphalt of this invention exhibits good fatigue resistance and deformation following ability, making it suitable for use in steel bridge deck pavement.

[0005] Because there are many substances that can be used as asphalt modifiers, many of them, when used in asphalt, either do not significantly improve fatigue resistance and deformation following ability, or while improving fatigue resistance and deformation following ability, reduce other properties such as high-temperature stability, durability, and water resistance. To achieve the above objectives, the inventors conducted extensive experimental research in the selection of the types and amounts of each component. Through continuous analysis and summarization, the following technical solution was finally obtained:

[0006] A highly elastic modified asphalt, the raw materials of which include the following components in parts by weight: 70-88 parts of base asphalt, 10-16 parts of SBS, 2-4 parts of nitrile rubber, 8-16 parts of naphthenic oil, 1-3 parts of RET modifier and 0.3-0.6 parts of anti-stripping agent.

[0007] In this invention, the base asphalt can be any type of base asphalt commonly used in the art, preferably 70# base asphalt.

[0008] In this invention, SBS represents a styrene-butadiene-styrene triblock copolymer. The SBS can be any conventional SBS in the art, preferably linear SBS. The molecular weight of the linear SBS can be 80,000 to 120,000, preferably 100,000 to 120,000, for example, 112,000. The type of linear SBS can be one or both of NR2 type SBS produced by Asahi Kasei Corporation of Japan and 1101 type SBS produced by Kraton Pharmaceuticals of the United States.

[0009] In this invention, the nitrile rubber can be conventional nitrile rubber in the art, preferably nitrile rubber with an acrylonitrile content of 31% to 35%, and the percentage is a mass percentage.

[0010] In this invention, the naphthenic oil can be a conventional naphthenic oil in the art, preferably a 4010 type naphthenic oil.

[0011] In this invention, RET represents a reactive elastomer terpolymer, and the RET modifier is preferably a copolymer of ethylene, butyl acrylate, and glycidyl methacrylate; wherein the mass fraction of butyl acrylate is preferably 28 wt%, and the mass fraction of glycidyl methacrylate is preferably 5.3 wt%; the RET modifier is, for example, DuPont. TM RET.

[0012] In this invention, the anti-stripping agent can be a conventional amine or non-amine anti-stripping agent in the art, preferably the KG80 type anti-stripping agent produced by Kao Corporation of Japan, which is a non-amine anti-stripping agent.

[0013] A preferred high-elasticity modified asphalt of the present invention comprises the following components in parts by weight: 70-78 parts base asphalt, 11-13 parts SBS, 3-4 parts nitrile rubber, 9-12 parts naphthenic oil, 1-2 parts RET modifier, and 0.3-0.4 parts anti-stripping agent. A more preferred high-elasticity modified asphalt of the present invention comprises the following components in parts by weight: 70-78 parts 70# base asphalt, 11-13 parts linear SBS, 3-4 parts nitrile rubber with an acrylonitrile content of 31%-35%, 9-12 parts naphthenic oil, 1-2 parts RET modifier, and 0.3-0.4 parts non-amine anti-stripping agent.

[0014] A preferred high-elasticity modified asphalt of the present invention comprises the following components in parts by weight: 77.7 parts base asphalt, 11 parts SBS, 4 parts nitrile rubber, 9 parts naphthenic oil, 2 parts RET modifier, and 0.3 parts anti-stripping agent. A more preferred high-elasticity modified asphalt of the present invention comprises the following components in parts by weight: 77.7 parts 70# base asphalt, 11 parts linear SBS with a molecular weight of 100,000 to 120,000, 4 parts nitrile rubber with an acrylonitrile content of 31% to 35%, 9 parts 4010 type naphthenic oil, 2 parts RET modifier, and 0.3 parts KG80 type anti-stripping agent manufactured by Kao Corporation of Japan.

[0015] A preferred high-elasticity modified asphalt of the present invention comprises the following components in parts by weight: 70.6 parts base asphalt, 13 parts SBS, 3 parts nitrile rubber, 12 parts naphthenic oil, 1 part RET modifier, and 0.4 parts anti-stripping agent. A more preferred high-elasticity modified asphalt of the present invention comprises the following components in parts by weight: 70.6 parts 70# base asphalt, 13 parts linear SBS with a molecular weight of 100,000 to 120,000, 3 parts nitrile rubber with an acrylonitrile content of 31% to 35%, 12 parts 4010 type naphthenic oil, 1 part RET modifier, and 0.4 parts KG80 type anti-stripping agent manufactured by Kao Corporation of Japan.

[0016] The present invention also provides a method for preparing the aforementioned highly elastic modified asphalt, which includes the following steps:

[0017] (1) Heat the base asphalt to 170-180℃, and add SBS, nitrile rubber, naphthenic oil, RET modifier and anti-stripping agent while shearing; (2) Continue heating to 190-210℃ and shear for 2-4 hours; (3) Develop at 190-210℃ for 4-6 hours.

[0018] In this invention, the shearing can be performed using conventional methods in the art, preferably using a colloid mill. The colloid mill can be a conventional colloid mill in the art. The shearing rate is preferably 6000-10000 r / min.

[0019] The present invention also provides a modified asphalt mixture comprising the aforementioned highly elastic modified asphalt and aggregates. Preferably, the highly elastic modified asphalt constitutes 4-6% by mass in the modified asphalt mixture, more preferably 5.8%.

[0020] In this invention, the aggregate can be stone material conforming to the gradation standard in the "Technical Specification for Construction of Asphalt Pavement on Highways". Preferably, the aggregate includes No. 1 aggregate with a particle size of 0-3mm, No. 2 aggregate with a particle size of 3-5mm, No. 3 aggregate with a particle size of 5-10mm, No. 4 aggregate with a particle size of 10-15mm, and mineral powder. More preferably, the aggregate includes 13.0% of No. 1 aggregate with a particle size of 0-3mm, 4.0% of No. 2 aggregate with a particle size of 3-5mm, 38.0% of No. 3 aggregate with a particle size of 5-10mm, 35.0% of No. 4 aggregate with a particle size of 10-15mm, and 10.0% mineral powder, where the percentages are by mass.

[0021] In this invention, according to the structural form, the modified asphalt mixture is preferably a modified asphalt mastic aggregate mixture, abbreviated as SMA, for example SMA-13.

[0022] In this invention, the modified asphalt mixture can be prepared by conventional methods in the art.

[0023] The present invention also provides the application of the highly elastic modified asphalt or the modified asphalt mixture in steel bridge deck paving.

[0024] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0025] The reagents and raw materials used in this invention are all commercially available.

[0026] The positive and progressive effects of this invention are as follows:

[0027] The high-elasticity modified asphalt of this invention meets the requirements for modified asphalt used in steel bridge decks in terms of penetration, ductility, and softening point, and has an elastic recovery rate of over 97%. Modified asphalt mixtures prepared using the high-elasticity modified asphalt of this invention improve fatigue resistance and deformation following ability while ensuring high-temperature stability, and also exhibit good waterproofing and durability. With excellent overall performance, it is highly suitable for steel bridge deck paving. Detailed Implementation

[0028] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0029] The grades of the components in the raw materials used in the following examples are as follows:

[0030] Base asphalt: 70# base asphalt;

[0031] SBS: NR2 type SBS manufactured by Asahi Kasei Corporation of Japan;

[0032] LG501 SBS: LG Corporation of South Korea;

[0033] Nitrile rubber: Nitrile rubber with an acrylonitrile content of 31-35%;

[0034] Naphthenic oil: Type 4010 naphthenic oil;

[0035] RET modifier: DuPont TM RET;

[0036] Anti-stripping agent: KG80 type anti-stripping agent manufactured by Kao Corporation of Japan.

[0037] Example 1

[0038] 77.7 parts of base asphalt were heated to 170℃, and the colloid mill was started with a shear rate of 6000 r / min. While shearing, 11 parts of SBS (molecular weight 112,000), 4 parts of nitrile rubber, 9 parts of naphthenic oil, 2 parts of RET modifier, and 0.3 parts of anti-stripping agent were added. After the addition was complete, the mixture was heated to 190℃, and the colloid mill continued shearing for 2 hours. The mixture was then pumped into a development tank and developed for 4 hours before being transferred to a finished product tank.

[0039] The obtained highly elastic modified asphalt was prepared into modified asphalt mixture SMA-13 ​​using conventional methods in the art. The mass percentage of highly elastic modified asphalt in SMA-13 ​​was 5.8%, and the aggregate composition is shown in Table 1.

[0040] Table 1

[0041]

[0042] Example 2

[0043] 70.6 parts of base asphalt were heated to 170℃, and the colloid mill was started. The shear rate was set to 10000 r / min, and while shearing, 13 parts of SBS (molecular weight 112,000), 3 parts of nitrile rubber, 12 parts of naphthenic oil, 1 part of RET modifier, and 0.4 parts of anti-stripping agent were added. After the addition was complete, the mixture was heated to 190℃, and the colloid mill continued shearing for 2 hours. The mixture was then pumped into a development tank and developed for 4 hours before being transferred to a finished product tank.

[0044] The highly elastic modified asphalt obtained was prepared into SMA-13 ​​mixture according to the method in Example 1.

[0045] Comparative Example 1

[0046] Eighty-two parts of base asphalt were heated to 170°C, and a colloid mill was started with a shear rate of 6000 r / min. While shearing, ten parts of LG501 type SBS (molecular weight 153,000) and nine parts of aromatic oil were added. After the addition was complete, the mixture was heated to 190°C, and the colloid mill continued shearing for 2 hours. The mixture was then pumped into a development tank and developed for 4 hours before being transferred to a finished product tank. The modified asphalt obtained was prepared into SMA-13 ​​mixture according to the method in Example 1.

[0047] Comparative Example 2

[0048] 70.6 parts of base asphalt were heated to 170°C, and a colloid mill was started with a shear rate of 10,000 r / min. While shearing, 10 parts of LG501 type SBS (molecular weight 153,000), 3 parts of nitrile rubber, 12 parts of naphthenic oil, 1 part of RET modifier, and 0.4 parts of anti-stripping agent were added. After the addition was complete, the mixture was heated to 190°C, and the colloid mill continued shearing for 2 hours. The mixture was then pumped into a development tank and developed for 4 hours before being transferred to a finished product tank. The modified asphalt obtained was prepared into SMA-13 ​​mixture according to the method in Example 1.

[0049] Comparative Example 3

[0050] 71.6 parts of base asphalt were heated to 170℃, and the colloid mill was started with a shear rate of 10,000 r / min. While shearing, 13 parts of SBS (molecular weight 112,000), 3 parts of nitrile rubber, 12 parts of naphthenic oil, and 0.4 parts of anti-stripping agent were added. After the addition was complete, the mixture was heated to 190℃, and the colloid mill was continued to shear for 2 hours. The mixture was then pumped into a development tank and developed for 4 hours before being transferred to a finished product tank.

[0051] Comparative Example 4

[0052] 76.6 parts of base asphalt were heated to 170℃, and the colloid mill was started. The shear rate was set to 10000 r / min, and while shearing, 13 parts of SBS (molecular weight 112,000), 3 parts of nitrile rubber, 6 parts of naphthenic oil, 1 part of RET modifier, and 0.4 parts of anti-stripping agent were added. After the addition was complete, the mixture was heated to 190℃, and the colloid mill continued shearing for 2 hours. The mixture was then pumped into a development tank and developed for 4 hours before being transferred to a finished product tank.

[0053] Comparative Example 5

[0054] 73.6 parts of base asphalt were heated to 170℃, and the colloid mill was started with a shear rate of 10,000 r / min. While shearing, 13 parts of SBS (molecular weight 112,000), 12 parts of naphthenic oil, 1 part of RET modifier, and 0.4 parts of anti-stripping agent were added. After the addition was complete, the mixture was heated to 190℃, and the colloid mill was continued to shear for 2 hours. The mixture was then pumped into a development tank and developed for 4 hours before being transferred to a finished product tank.

[0055] Effect Example

[0056] (1) Performance tests were conducted on the modified asphalt and modified asphalt mixture SMA-13 ​​prepared in Examples 1, 2, and Comparative Examples 1-5 according to conventional methods in the art. The test items, index requirements, and test methods are shown in Table 2, where the index requirements are derived from the "Code for Construction and Acceptance of Finished and Semi-finished Road and Drainage Pipelines" (DG / TJ 08-87-2016). The measured values ​​of the modified asphalt and modified asphalt mixture SMA-13 ​​prepared in Examples 1, 2, and Comparative Examples 1-5 are shown in Table 3.

[0057] (2) Test method for low-temperature bending (-20℃) of binder

[0058] The modified asphalts prepared in Examples 1 and 2 and Comparative Examples 1-5 were poured into small beam specimens formed in 20mm×20mm×120mm molds, slightly higher than the mold. Due to the high polymer content of the modified asphalt and the lower mold temperature compared to the asphalt, the shrinkage rate in the middle of the sample was faster than at the edges, resulting in the middle of the sample being lower than the mold. To ensure the geometric dimensions of the specimen, secondary material replenishment may be necessary. The specimens were cooled at low temperature to prevent deformation during leveling. After removing the sample that protruded above the mold with a hot scraper, they were demolded and kept at the test temperature for 3-3.5 hours. The specimens were placed on the supports of the testing machine, with a support spacing of 80mm. A load was applied at a speed of 100mm / min at the center of the span, and the deformation and load were recorded. The straight line segment of the load-deformation curve was extended to the horizontal axis, and the intersection point was taken as the origin. Similar to the calculation method for the mixture bending test, the calculation methods for flexural tensile strength, flexural ultimate strain, flexural tensile strain energy, and flexural stiffness modulus are as follows:

[0059] Flexural tensile strength

[0060] Bending limit strain

[0061] Bending strain energy = σ × ε

[0062]

[0063] Where: b—width of the specimen (mm), a specified value, 20mm;

[0064] h—Height of the specimen (mm), a specified value, 20mm;

[0065] l—the distance between support points (mm), which is a specified value of 80mm;

[0066] P—Maximum load (N), a measured value;

[0067] d—Strain (mm) at maximum load, a measured value. The test results are shown in Table 3.

[0068] Table 2

[0069]

[0070]

[0071] Table 3

[0072]

[0073]

[0074] As shown in Tables 2 and 3, the high-elasticity modified asphalt prepared in Examples 1 and 2, and the modified asphalt mixture SMA-13 ​​prepared from them, all meet the required performance indicators. The elastic recovery rate of the high-elasticity modified asphalt in Examples 1 and 2 is above 97%, and the low-temperature PG grading is better than that of Comparative Examples 1-2 and 4-5. The SMA-13 ​​made from the high-elasticity modified asphalt in Examples 1 and 2 has a freeze-thaw splitting strength ratio of over 90% and a low-temperature bending test failure strain of over 8800.

[0075] Compared with the examples, Comparative Example 1 has a large difference in raw material composition. Although its elastic recovery rate and the corresponding freeze-thaw splitting strength of SMA-13 ​​are relatively good, its low-temperature bending test failure strain is only 3500εμ, and its low-temperature fatigue resistance is far lower than that of Examples 1-2.

[0076] Compared with the example, Comparative Example 2 used LG501 type SBS with a molecular weight of 153,000. Its elastic recovery rate and the corresponding freeze-thaw splitting strength and low-temperature bending test failure strain of SMA-13 ​​were poor. This may be due to the excessive melt viscosity caused by a molecular weight of more than 120,000, resulting in a large difference in segregation softening point.

[0077] Compared with the examples, Comparative Example 3 did not add RET modifier. Although its performance in all aspects was relatively better, it still had a certain gap with the effect of the examples. This may be because RET modifier can work together with other components to further improve the performance of highly elastic modified asphalt.

[0078] Compared with the examples, Comparative Example 4 differs in that it has a lower weight fraction of naphthenic oil, resulting in better elastic recovery and freeze-thaw splitting strength of the corresponding SMA-13, but poor low-temperature bending test failure strain of its SMA-13.

[0079] Compared with the example, Comparative Example 5 did not contain nitrile rubber. Its elastic recovery rate and the corresponding freeze-thaw splitting strength of SMA-13 ​​were better, but its low-temperature bending test failure strain of SMA-13 ​​was very poor.

[0080] In summary, the modified asphalt mixture of the present invention has good low-temperature fatigue resistance and deformation following ability.

Claims

1. A highly elastic modified asphalt, characterized in that, The raw materials include the following components in parts by weight: 70-88 parts of base asphalt, 10-16 parts of SBS, 2-4 parts of nitrile rubber, 8-16 parts of naphthenic oil, 1-3 parts of RET modifier, and 0.3-0.6 parts of anti-stripping agent; the SBS is linear SBS with a molecular weight of 80,000-120,000; the nitrile rubber is nitrile rubber with an acrylonitrile content of 31%-35%, and the percentages are by weight. The highly elastic modified asphalt is prepared through the following steps: (1) Heat the base asphalt to 170-180°C, and add the SBS, nitrile rubber, naphthenic oil, RET modifier and anti-stripping agent while shearing; (2) Continue heating to 190-210°C and shear for 2-4 hours; (3) Develop at 190-210°C for 4-6 hours. The shearing is performed using a colloid mill; the shearing rate is 6000-10000 r / min.

2. The highly elastic modified asphalt as described in claim 1, characterized in that, The raw materials for the high-elasticity modified asphalt include the following components in parts by weight: 70-78 parts of base asphalt, 11-13 parts of SBS, 3-4 parts of nitrile rubber, 9-12 parts of naphthenic oil, 1-2 parts of RET modifier, and 0.3-0.4 parts of anti-stripping agent.

3. The highly elastic modified asphalt as described in claim 1, characterized in that, The raw materials for the highly elastic modified asphalt include the following components in parts by weight: 77.7 parts base asphalt, 11 parts SBS, 4 parts nitrile rubber, 9 parts naphthenic oil, 2 parts RET modifier, and 0.3 parts anti-stripping agent.

4. The highly elastic modified asphalt as described in claim 1, characterized in that, The raw materials for the high-elasticity modified asphalt include the following components in parts by weight: 70.6 parts base asphalt, 13 parts SBS, 3 parts nitrile rubber, 12 parts naphthenic oil, 1 part RET modifier, and 0.4 parts anti-stripping agent.

5. The highly elastic modified asphalt as described in claim 1, characterized in that, The base asphalt is 70# base asphalt; And / or, the naphthenic oil is a 4010 type naphthenic oil; And / or, the RET modifier is a copolymer of ethylene, butyl acrylate, and glycidyl methacrylate.

6. The highly elastic modified asphalt as described in claim 5, characterized in that, In the RET modifier, the mass fraction of butyl acrylate is 28 wt%. And / or, in the RET modifier, the mass fraction of glycidyl methacrylate is 5.3 wt%.

7. The highly elastic modified asphalt as described in claim 6, characterized in that, The RET modifier is DuPont. TM RET.

8. The highly elastic modified asphalt as described in claim 5, characterized in that, The molecular weight of the linear SBS is 100,000 to 120,000. And / or, the linear SBS is one or both of the NR2 type SBS manufactured by Asahi Kasei Corporation of Japan and the 1101 type SBS manufactured by Kraton Pharmaceuticals of the United States.

9. The highly elastic modified asphalt as described in claim 8, characterized in that, The linear SBS has a molecular weight of 112,000.

10. The highly elastic modified asphalt as described in claim 1, characterized in that, The anti-stripping agent is an amine or non-amine anti-stripping agent.

11. The highly elastic modified asphalt as described in claim 10, characterized in that, The anti-stripping agent is the KG80 type anti-stripping agent manufactured by Kao Corporation of Japan.

12. The method for preparing highly elastic modified asphalt according to any one of claims 1 to 11, characterized in that, It includes the following steps: (1) Heat the base asphalt to 170-180°C, and add the SBS, nitrile rubber, naphthenic oil, RET modifier and anti-stripping agent while shearing; (2) Continue heating to 190-210°C and shear for 2-4 hours; (3) Develop at 190-210°C for 4-6 hours.

13. The method for preparing highly elastic modified asphalt as described in claim 12, characterized in that, The shearing was performed using a colloid mill; And / or, the shearing rate of the shearing is 6000-10000 r / min.

14. A modified asphalt mixture, characterized in that, It comprises the highly elastic modified asphalt and aggregate as described in any one of claims 1 to 11.

15. The modified asphalt mixture as described in claim 14, characterized in that, The high-elasticity modified asphalt accounts for 4-6% of the mass percentage of the modified asphalt mixture.

16. The modified asphalt mixture as described in claim 15, characterized in that, The high-elasticity modified asphalt accounts for 5.8% of the mass of the modified asphalt mixture.

17. The application of the highly elastic modified asphalt as described in any one of claims 1 to 11 or the modified asphalt mixture as described in any one of claims 14 to 16 in the pavement of steel bridge decks.

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