Modified asphalt for durable thin layer pavement, preparation method and application thereof, and wearing layer

Abstract

The invention belongs to the technical field of polymer materials, and discloses modified asphalt for durable thin layer pavement, a preparation method and application thereof and a wearing layer. The modified asphalt comprises the following components in parts by mass: 100 parts of asphalt, 10-20 parts of a thermoplastic elastomer, 2-5 parts of a tackifier and an auxiliary agent, the tackifier is a phthalonitrile resin; the plastic elastomer contains not less than 90 wt% of SBS; according to the modified asphalt, the tackifier and the thermoplastic elastomer are used for synergistically modifying the asphalt, so that the obtained modified asphalt has excellent high-temperature performance, low-temperature performance and aging resistance at the same time, and is particularly suitable for durable thin-layer pavement, and a wearing layer prepared from the modified asphalt has excellent fatigue durability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of asphalt materials, and particularly relates to a modified asphalt for durable thin-layer paving, a preparation method, use and wearing layer thereof. BACKGROUND

[0002] At present, ultra-thin overlay is one of the most commonly used technical means for highway maintenance, and is widely used in preventive maintenance of highway asphalt and cement pavement, bridge deck and tunnel, and upgrading and reconstruction of urban road asphalt pavement, which can significantly improve the driving comfort and safety of the road. However, the service life of the ultra-thin overlay is usually not more than 5 years. Generally, after 3 years of ultra-thin overlay, reflection cracks begin to appear, and after 5 years of use, the surface begins to appear loose and loose. The phenomenon is far lower than the design service life of 15 years of newly built asphalt pavement. The asphalt binder in the ultra-thin overlay is the core, and the way to improve the service durability of the ultra-thin overlay is to improve the performance of the asphalt binder. In the specification JTG / T 5142-01-2021, the binder used for ultra-thin overlay is generally high-viscosity and high-elasticity asphalt, and the core technical index is softening point > 90℃, 60℃ dynamic viscosity > 200 million Pa·s, 5℃ ductility > 40cm, and the fatigue life of the thin-layer overlay mixture mixed with high-viscosity and high-elasticity asphalt is generally 100 million times. If you want to further improve the service durability of the ultra-thin overlay, it is the key to improve the performance indicators of the asphalt binder, including the high-temperature, low-temperature, aging resistance and fatigue resistance of the asphalt.

[0003] In the field of asphalt modification technology, the improvement of high-temperature performance and low-temperature performance indicators is mutually contradictory. The asphalt with excellent high-temperature performance index generally has general low-temperature performance index, and vice versa. The low-temperature performance of the asphalt is excellent, but the high-temperature performance index is not outstanding. Since the ultra-thin overlay is in the most surface layer of the road, it directly bears the combined action of load and environment, and the working environment is more severe than other ordinary asphalt surface layers. Therefore, simultaneously improving the high-temperature and low-temperature performance of high-viscosity and high-elasticity modified asphalt is of great significance to improve the service durability of the ultra-thin overlay.

[0004] Therefore, the technical problem to be solved by the present application is how to develop a modified asphalt suitable for durable thin-layer paving, which can significantly increase the service durability of the wearing layer. SUMMARY

[0005] The present application aims to provide a modified asphalt for durable thin-layer paving, which contains a thermoplastic elastomer and a tackifier, and the tackifier is phthalonitrile resin. The tackifier and the thermoplastic elastomer are used to synergistically modify the asphalt, so that the obtained modified asphalt has excellent high-temperature performance, low-temperature performance and fatigue durability, and is particularly suitable for durable thin-layer paving.

[0006] Meanwhile, the application further provides a preparation method and application of the super modified asphalt, and a wearing layer prepared from the modified asphalt.

[0007] To achieve the above object, the application provides the following technical scheme.

[0008] A modified asphalt for durable thin layer pavement, comprising the following components in mass fraction: asphalt 100 parts, thermoplastic elastomer 10-20 parts, tackifier 2-5 parts and auxiliary agent.

[0009] The tackifier is phthalonitrile resin.

[0010] The plastic elastomer contains not less than 90wt% of SBS.

[0011] Preferably, the plastic elastomer further contains one or more combinations of SIS and SEBS.

[0012] Preferably, the asphalt is petroleum asphalt with a penetration of 30-500.

[0013] More preferably, the asphalt is No. 70 road A-grade petroleum asphalt.

[0014] Preferably, the auxiliary agent contains plasticizer 6-10 parts, dispersant 2-6 parts, antioxidant 1-2 parts and vulcanizing agent 1-2 parts in mass fraction.

[0015] More preferably, the plasticizer is one or more combinations of di-n-butyl phthalate, trioctyl trimellitate and pentaerythritol tetraoleate; the dispersant is N-methyl-2-pyrrolidone; the antioxidant is 2,6-di-tert-butyl-p-cresol; and the vulcanizing agent is VA-7.

[0016] In addition, the application discloses a preparation method of the modified asphalt as described above, and the specific method is as follows: the asphalt is heated to 200 DEG C, the thermoplastic elastomer and the tackifier are added and stirred, the temperature is reduced to 180 DEG C after 30 min of stirring, the plasticizer, the dispersant and the antioxidant are added in sequence, then stirring for 4 h, finally the vulcanizing agent is added and stirred for 2 h, so that the modified asphalt is prepared.

[0017] In addition, the application discloses application of the modified asphalt in preparing a wearing layer for durable thin layer pavement.

[0018] Finally, the application discloses a wearing layer of modified asphalt composition for durable thin layer pavement, and the wearing layer contains the modified asphalt as described above.

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] The modified asphalt prepared by the application has the following advantages: the modified asphalt has a softening point > 110℃ and a 5℃ ductility > 60cm, and the high-temperature and low-temperature performance indexes are simultaneously improved; the modified asphalt has a remarkable anti-aging performance, and the 5℃ ductility of the asphalt after PAV aging is > 50cm, and the modified asphalt can resist long-term aging caused by sunlight and ultraviolet radiation; the 60℃ dynamic viscosity of the modified asphalt is > 2 million Pa·s, which is more than 10 times of the dynamic viscosity index required in the existing standard, and the high-temperature deformation resistance of the thin-layer surface mixture is remarkably improved; and the thin-layer asphalt mixture prepared by using the modified asphalt has a fatigue life > 1 million times under the condition of 15℃ and 2000με, the fatigue anti-cracking performance is remarkably improved, and the anti-reflection cracking performance of the thin-layer surface is effectively enhanced. DETAILED DESCRIPTION

[0021] The technical solutions of the application will be described clearly and completely below by combining with the embodiments of the application. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments. Based on the embodiments in the application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application. The reagents or instruments used are not marked with the manufacturers, and are all conventional products that can be purchased in the market.

[0022] Product information:

[0023] Asphalt: 70# road A-grade petroleum asphalt, purchased from Dongguan Taihe Asphalt Product Co., Ltd., Esso 70# base asphalt, with a penetration of 72(0.1mm);

[0024] SBS: YH791-H produced by Sinopec Baling Petrochemical Plant, with a styrene content of 30wt%;

[0025] SIS: JH-8153 produced by Ningbo Jinhaichengguang Chemical Co., Ltd., with a styrene content of 15wt% and a diblock content of 20wt%;

[0026] SEBS: TAIPOL 6152P produced by TSRC Taixing Petrochemical Co., Ltd.;

[0027] Phthalonitrile resin: phthalonitrile resin produced by Wuhan Chengtian Fine Chemical Co., Ltd., CAS: 91-15-6; first part

[0028] The following examples and comparative examples are prepared by the following preparation method.

[0029] The asphalt is heated to 200℃, the thermoplastic elastomer and tackifier are added and stirred, the temperature is reduced to 180℃ after stirring for 30 min, the plasticizer, dispersant and antioxidant are added in sequence, then stirred for 4 h, finally the vulcanizing agent is added and stirred for 2 h, thus the modified asphalt is prepared.

[0030] The formula table of each example and comparative example is shown in Table 1,

[0031] Table 1 Formula table of modified asphalt (mass fraction)

[0032]

[0033] The specific components of the thermoplastic elastomer, tackifier and tackifier can refer to Table 2;

[0034] Table 2 Specific component table

[0035]

[0036] Example 8

[0037] The example 3 is basically the same, except that the plasticizer pentaerythritol tetraoleate and other mass are replaced by acetyl citric acid tributyl ester.

[0038] Example 9

[0039] The example 3 is basically the same, except that the antioxidant 2,6-di-tert-butyl-p-cresol and other mass are replaced by p-phenylenediamine.

[0040] Example 10

[0041] The example 3 is basically the same, except that the vulcanizing agent VA-7 and other mass are replaced by sulfur powder.

[0042] Performance detection

[0043] The modified asphalt prepared in each example and comparative example is tested as follows;

[0044] Referring to “Highway Engineering Asphalt and Asphalt Mixture Test Procedures” JTG E20-2011;

[0045] Softening point: T 0606-2011;

[0046] 60℃ dynamic viscosity: T 0620-2000;

[0047] 5℃ ductility: T 0605-2011;

[0048] PAV aging test method: T 0630-2011;

[0049] Fatigue test method: T0739-2011;

[0050] The relevant test results are shown in Tables 3 and 4.

[0051] Table 3 Modified asphalt data table

[0052]

[0053]

[0054] Table 4 Modified asphalt data table after 1st PAV long-term aging

[0055]

[0056] Data analysis

[0057] 1. As can be seen from the data of Examples 1-5, in the dosage range of the application, the modified asphalt obtained has better performance in softening point, 60°C dynamic viscosity and 5°C ductility, and the performance of Example 5 is the best.

[0058] 2. As can be seen from the data of Example 3 and Examples 6-7, when the thermoplastic elastomer is used in combination with SBS and SIS or SEBS, the performance of the modified asphalt obtained is further improved.

[0059] 3. As can be seen from the data of Example 3 and Examples 8-10, the preferred plasticizer of the application is pentaerythritol tetraoleate, the antioxidant is 2,6-di-tert-butyl-p-cresol, and the vulcanizing agent is VA-7.

[0060] 4. As can be seen from the data of Example 3 and Comparative Examples 1-4, the tackifier phthalonitrile resin is a crucial component of the application and cannot be omitted, and it can synergistically improve the performance of the modified asphalt with the thermoplastic elastomer; the effect of using other tackifiers such as PE, EVA, and terpene resin in combination with SBS is far inferior to that of phthalonitrile resin.

[0061] 5. As can be seen from the data of Example 3 and Comparative Examples 5-6, the type of thermoplastic elastomer selected by the application is also crucial, and SBS is the most preferred, and the use of other thermoplastic elastomers such as SEPS and TPV has poor effect.

[0062] Second part

[0063] The modified asphalt of Example 3, Examples 6-7, and Comparative Examples 1-6 is prepared to obtain a wearing layer; the formula ratio is as follows:

[0064] Modified asphalt: 2mm machine-made sand: 4mm basalt: 7mm basalt: mineral powder: polyester fiber = 8: 15: 40: 40: 5: 0.3;

[0065] The specific preparation method is:

[0066] The stone is heated to 190℃, the pitch is heated to 185℃, the stone is first mixed with the fiber for 90 seconds, then the high viscosity pitch is mixed for 90 seconds, and finally the mineral powder is mixed for 90 seconds to obtain the ultra-thin surface course mixture wearing layer.

[0067] Among them, example 3 corresponds to wearing layer 1, examples 6-7 correspond to wearing layers 2-3, and comparative examples 1-6 correspond to wearing layers 4-9.

[0068] The wearing layer obtained above is tested according to the following method:

[0069] According to the fatigue test method: T0739-2011, the test conditions are 15℃ and the strain level is 2000με.

[0070] The results are shown in Table 5.

[0071] Table 5: Wearing layer test data table

[0072] fatigue life / cycles wearing course 1 1367480 wearing course 2 1749670 wearing course 3 1536920 wearing course 4 123580 wearing course 5 258490 wearing course 6 324570 wearing course 7 379630 wearing course 8 248950 wearing course 9 204830

[0073] As shown by the data in Table 6, the wearing layer prepared from the modified pitch of the examples has excellent fatigue life, especially the wearing layer 2. The wearing layer prepared from the modified pitch of the comparative examples has fatigue life of 100,000-400,000 times, which is much less than that of the wearing layer prepared from the modified pitch of the examples. This shows that the modified pitch prepared by the present application is particularly suitable for durable thin layer paving.

[0074] It is apparent for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, but can be implemented in other concrete forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all aspects as illustrative and not restrictive, and the scope of the present application is defined by the appended claims rather than the above description, and all changes falling within the meaning and range of the equivalent elements of the claims are intended to be embraced in the present application.

Claims

1. A modified asphalt for a durable thin layer pavement, characterized by, By mass fraction, it comprises the following components: asphalt 100 parts, thermoplastic elastomer 10-20 parts, tackifier 2-5 parts and auxiliary agent; The tackifier is o-phthalonitrile resin. The plastic elastomer contains not less than 90wt% SBS.

2. The modified bitumen of claim 1, wherein, The plastic elastomer also contains one or more combinations of SIS and SEBS.

3. The modified bitumen of claim 1, wherein, The asphalt is petroleum asphalt, and the penetration is 30-500.

4. The modified bitumen of claim 4, wherein, The asphalt is No. 70 road A-grade petroleum asphalt.

5. The modified bitumen of claim 1, wherein, The auxiliary agent contains plasticizer 6-10 parts, dispersant 2-6 parts, antioxidant 1-2 parts and vulcanizing agent 1-2 parts by mass fraction.

6. The modified bitumen of claim 5, wherein, The plasticizer is one or more combinations of di-n-butyl phthalate, trioctyl trimellitate and pentaerythritol tetraoleate; the dispersant is N-methyl-2-pyrrolidone; the antioxidant is 2,6-di-tert-butyl-p-cresol; and the vulcanizing agent is VA-7.

7. The method of producing modified bitumen according to any one of claims 1 to 6, wherein The specific method is: heating asphalt to 200℃, adding thermoplastic elastomer and tackifier to stir, reducing the temperature to 180℃ after stirring for 30 min, adding plasticizer, dispersant and antioxidant in sequence, then stirring for 4 h, finally adding vulcanizing agent to stir for 2 h, thus obtaining the modified asphalt.

8. Use of the modified asphalt according to any one of claims 1-6 in preparing wearing course for durable thin layer pavement.

9. A wearing course for a durable thin surfacing, characterized in that The wearing course contains the modified asphalt according to any one of claims 1-6.

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