Asphalt modifier for'dry method 'bridge deck pavement as well as preparation method and application of asphalt modifier

Abstract

The invention belongs to the technical field of road engineering materials, and particularly relates to an asphalt modifier for'dry process' bridge deck pavement as well as a preparation method and application thereof, and the asphalt modifier is characterized by comprising the following components in parts by weight: 50-70 parts of styrene-butadiene-styrene block copolymer (SBS), 1-5 parts of aluminum silicate, 5-10 parts of polyvinyl alcohol, 0.5-1 part of zinc oxide and 20-35 parts of epoxy resin. The asphalt modifier prepared by the invention can be used for asphalt modification, and the further prepared asphalt mixture can achieve the purposes of high-temperature rutting resistance, low-temperature cracking resistance and water damage resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of road engineering, and specifically relates to an asphalt modifier for "dry process" bridge deck paving, and a preparation method and application thereof. Background Art

[0002] In recent years, the construction of long-span bridges in my country has developed rapidly, and steel box girder bridge decks are usually paved with asphalt concrete. In order to meet the high strength, high toughness, high viscosity and other performance requirements of bridge paving for asphalt concrete, the use of special modified asphalt for production has become the mainstream. Among them, SBS (styrene-butadiene-styrene block copolymer) modified asphalt is widely used due to its excellent tensile properties, good low temperature resistance and anti-skid properties. However, due to the large differences in composition and structure between SBS and base asphalt, problems such as poor compatibility and system instability often occur during the blending process, and phase separation is prone to occur during high-temperature storage and processing, affecting the performance of asphalt.

[0003] At present, SBS modified asphalt usually adopts the "wet" modification process. After the modifier is premixed with organic asphalt in the asphalt processing plant, it is fully ground through a shearing machine and developed for several hours to finally obtain modified asphalt. Although this process technology is relatively mature, it has many problems: first, the process requires a large amount of land resources to build an asphalt plant; second, the processing process consumes a lot of resources and causes environmental pollution; in addition, the modified asphalt needs to be transported to the mixing station for a second time, which increases transportation costs and energy consumption. In addition, during the high-temperature shearing and development process, the modifier molecules may undergo thermal decomposition or degradation, affecting their performance. The "dry" modification process is to directly add the modifier to the asphalt mixing plant to work with aggregates and asphalt to improve the performance of the asphalt mixture. This convenient process has gradually gained attention, but these modifiers still have problems such as insufficient water stability and crack resistance that need to be improved. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides an asphalt modifier for "dry process" bridge deck paving, and a preparation method and application thereof.

[0005] Specifically, the detailed technical solution adopted in this application is as follows.

[0006] A "dry method" asphalt modifier for bridge deck paving comprises the following components in parts by weight: 50-70 parts of SBS, 1-5 parts of aluminum silicate, 5-10 parts of polyvinyl alcohol, 0.5-1 part of zinc oxide, and 20-35 parts of epoxy resin.

[0007] In some embodiments, a "dry process" asphalt modifier for bridge deck paving includes the following components, in parts by weight: 60 parts of SBS, 5 parts of aluminum silicate, 8 parts of polyvinyl alcohol, 0.7 parts of zinc oxide, and 30 parts of epoxy resin.

[0008] The "dry method" asphalt modifier for bridge deck paving has a particle size of SBS less than 2.5 mm and a particle size of other components less than 100 μm.

[0009] The present invention also provides a method for preparing the above-mentioned "dry process" asphalt modifier for bridge deck paving, comprising the following steps:

[0010] S1: The SBS is sheared and ground by an impact mill for 1 to 3 minutes, and the particle size of the SBS particles after shearing is less than 1 mm.

[0011] S2: Premix the aluminum silicate, polyvinyl alcohol, zinc oxide and epoxy resin and add them into a ball mill. Control the speed of the ball mill to 60%-80% of the critical speed and grind for 100-120 minutes to prepare a mixed powder with a particle size of less than 100 microns.

[0012] S3: Using a fluidized bed mixer, mix the SBS particles prepared in steps S1 and S2 with the mixed powder for 10-15 minutes to prepare an asphalt modifier.

[0013] The present invention also provides a method for preparing the above-mentioned "dry process" modified asphalt mixture, comprising the following steps:

[0014] S1: mixing the asphalt modifier with aggregate at a temperature of 170-180° C. for 60-120 seconds to obtain a mixture 1;

[0015] S2: Mixing the mixed mixture 1 with base asphalt at a mixing temperature of 170-180° C. for 60-120 seconds to obtain a mixture 2;

[0016] S3: adding mineral powder to the mixture 2 and mixing the mixture for 60-120 seconds to obtain the asphalt mixture.

[0017] The present invention also provides the application of the above-mentioned asphalt mixture in the paving and repairing of steel bridge decks, tunnels, airports, high-grade highways and urban trunk roads.

[0018] Effects achieved by the present invention:

[0019] (1) Environmental protection and resource conservation: The dry modification process reduces high-temperature shearing and long-term development process, thereby reducing energy consumption and exhaust emissions, and reducing environmental pollution. In addition, it avoids the need for the construction of asphalt processing plants, saves land resources, and reduces the cost and energy consumption of secondary transportation.

[0020] (2) Improve production efficiency and reduce the risk of pyrolysis: Since the dry process does not require complicated pretreatment and high-temperature operation, it can shorten the production cycle and improve production efficiency. At the same time, low-temperature operation avoids the risk of pyrolysis and molecular degradation of the modifier at high temperature, thereby maintaining the stability and performance of the modifier.

[0021] (3) Improve asphalt performance: The dry modification process can effectively improve the asphalt's crack resistance, water damage resistance and high temperature stability by directly mixing the modifier with asphalt and aggregate in the mixing plant, thereby improving the overall use effect and durability of asphalt. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the flow chart of modified asphalt mixture preparation. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the examples. The equipment and reagents used in each embodiment and test example can be obtained from commercial sources unless otherwise specified. The specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] Based on the information contained in this application, it is easy for those skilled in the art to make various changes to the precise description of the present invention without departing from the spirit and scope of the appended claims. It should be understood that the scope of the present invention is not limited to the defined process, properties or components, because these embodiments and other descriptions are only for illustrating specific aspects of the present invention. In fact, various changes that the technicians in this field or related fields can obviously make to the embodiments of the present invention are all covered within the scope of the appended claims.

[0025] In order to better understand the present invention but not to limit the scope of the present invention, all the numbers used in this application to express the amount, percentage, and other numerical values ​​should be understood as modified by the word "approximately" in all cases. Therefore, unless otherwise specified, the numerical parameters listed in the specification and the appended claims are approximate values, which may be changed according to the different ideal properties attempted to be obtained. Each numerical parameter should at least be regarded as obtained based on the reported significant figures and by conventional rounding methods. In the present invention, "about" means within 10% of a given value or range, preferably within 5%.

[0026] Unless otherwise specified, the reagents and materials used in the embodiments of the present invention can be purchased from the market, wherein the base asphalt is Shell 70#A grade base asphalt, and the SBS-T modifier is a commercially available instant modifier.

[0027] Example 1

[0028] A "dry process" asphalt modifier for bridge deck paving is prepared according to the components in Table 1 below.

[0029] Table 1 Preparation of asphalt modifiers with different components

[0030]

[0031] The preparation method is: after weighing SBS (Kraton D-KX401), aluminum silicate, PVA (Aladdin 1799), zinc oxide and epoxy resin (epoxy resin E51 CAS: 61788-97-4), shear and grind the SBS with an impact mill for 3 minutes, and the particle size of the SBS particles after shearing is less than 1mm. After premixing aluminum silicate, polyvinyl alcohol, zinc oxide and epoxy resin, add them to a ball mill, control the speed of the ball mill to 60%-80% of the critical speed, grind for 100 minutes to prepare a mixed powder with a particle size of less than 100 microns. Use a fluidized bed mixer to mix the powder for 10-15 minutes to prepare an asphalt modifier.

[0032] Example 2

[0033] The six modifiers in Example 1 were applied to prepare modified asphalt mixtures using the prepared six modifiers, and then modified asphalt was extracted from the mixtures. The performance of the asphalt modified by the six modifiers was tested. The modification of the asphalt mixture and the preparation method of the modified asphalt are as follows:

[0034] S1: 20 parts of SBS modifier and 10 parts of aggregate are added to a mixing pot for dry mixing at a temperature of 180°C and a mixing time of 90 seconds;

[0035] S2: Add 65 parts of base asphalt into the mixing pot and continue stirring at a mixing temperature of 180°C and a mixing time of 100 seconds;

[0036] S3: Add 5 parts of mineral powder (ground limestone powder) and mix for 90 seconds;

[0037] S4: curing the finished mixture in an oven at 170° C. for 60 min;

[0038] S5: Pour the mixture into a metal mesh and collect the modified asphalt by desorption at 190°C.

[0039] According to the different groups of SBS modifiers, see Table 2:

[0040] Table 2 Regeneration agents corresponding to different modified asphalts

[0041] Grouping SBS Modifier Modified asphalt 1 Modifier 1 Modified asphalt 2 Modifier 2 Modified asphalt 3 Modifier 3 Modified asphalt 4 Modifier 4 Modified asphalt 5 Modifier 5 Modified asphalt 6 Modifier 6

[0042] Example 3

[0043] The road performance capability of the modified asphalt prepared by the present invention was evaluated by high temperature rutting test, beam bending test and freeze-thaw splitting test.

[0044] S1: 20 parts of the six modifiers prepared in Example 1 are mixed with 10 parts of aggregate respectively, the mixing temperature of the asphalt modifier and the aggregate is 170-180° C., and the mixing time is 60-120 seconds;

[0045] S2: The mixed mixture is mixed with 65 parts of base asphalt respectively, the mixing temperature is 170-180°C, and the mixing time is 60-120 seconds;

[0046] S3: adding 5 parts of mineral powder respectively for mixing, the mixing time is 60-120 seconds, to obtain the asphalt mixture;

[0047] The six modified asphalt mixtures shown in Table 3 were prepared according to the above method.

[0048] Table 3 Modified asphalt mixture

[0049] Grouping Modifier Modified asphalt mixture 1 Modifier 1 Modified asphalt mixture 2 Modifier 2 Modified asphalt mixture 3 Modifier 3 Modified asphalt mixture 4 Modifier 4 Modified asphalt mixture 5 Modifier 5 Modified asphalt mixture 6 Modifier 6

[0050] Comparative Example 1

[0051] The SBS-T (Guolu Hi-Tech) modifier was applied to prepare a modified asphalt mixture, and then the modified asphalt was extracted from the mixture. The performance of the extracted modified asphalt was tested. The modification of the asphalt mixture and the preparation method of the modified asphalt are as follows:

[0052] S1: 20 parts of SBS-T modifier and 10 parts of aggregate are added to a mixing pot for dry mixing at a temperature of 180°C and a mixing time of 90 seconds;

[0053] S2: Add 65 parts of base asphalt into the mixing pot and continue stirring at a mixing temperature of 180°C and a mixing time of 100 seconds;

[0054] S3: Add 5 parts of mineral powder (ground limestone powder) and mix for 90 seconds;

[0055] S4: curing the finished mixture in an oven at 170° C. for 60 min;

[0056] S5: Pour the mixture into a metal mesh and collect the modified asphalt by desorption at 190°C.

[0057] According to the different groups of SBS modifiers, see Table 4:

[0058] Table 4 Commercial modifiers and modified asphalt

[0059] Grouping SBS Modifier Modified asphalt 7 SBS-T Modifier

[0060] Comparative Example 2

[0061] The road performance capability of modified asphalt prepared using SBS-T modifier was evaluated by high temperature rutting test, beam bending test and freeze-thaw splitting test.

[0062] S1: Mix 20 parts of SBS-T modifier with 10 parts of aggregate. The mixing temperature of asphalt modifier and aggregate is 170-180°C and the mixing time is 60-120 seconds.

[0063] S2: mixing the mixed mixture with base asphalt at a mixing temperature of 170-180°C for 60-120 seconds;

[0064] S3: adding mineral powder and mixing for 60-120 seconds to obtain the asphalt mixture;

[0065] The modified asphalt mixtures in Table 5 were prepared according to the above method.

[0066] Table 5 Modified asphalt mixture

[0067] Grouping Modifier Modified asphalt mixture7 SBS-T Modifier

[0068] Experimental Example 1:

[0069] The modified asphalt collected in the examples and comparative examples was tested for penetration, ductility and softening point, and the experimental results are shown in Table 6. The penetration and softening point of the asphalt modified by the modifier can be significantly improved, and in particular, the asphalt modified by the modifier prepared by the present invention performs well in the penetration test. This shows that the modifier prepared by the present invention can enable the modified asphalt to form a good spatial network structure.

[0070] Softening point test: T0606-2011 asphalt softening point test (ring and ball method) is used.

[0071] Needle penetration test: refer to T0604-2001 asphalt needle penetration test.

[0072] Ductility test: refer to T0605-2011 asphalt ductility test.

[0073] Table 6 5℃ ductility of modified asphalt

[0074]

[0075]

[0076] The cracking of the road surface is closely related to the low-temperature deformation capacity of asphalt. When stretched and deformed, the attraction and friction resistance between asphalt molecules without modifiers limit the deformation and the ductility will decrease. The modifier has a certain flexibility and good deformation capacity. The addition of the modifier improves the ductility of the modified asphalt. The modifier and asphalt of the present invention can form a multi-dimensional network structure. Under the action of external force, the matrix asphalt and the modifier embedded in the matrix asphalt are synergistically stressed, which improves the low-temperature tensile resistance of the asphalt.

[0077] Experimental Example 2

[0078] The road performance capability of the modified asphalt prepared by the present invention was evaluated by high temperature rutting test, beam bending test and freeze-thaw splitting test.

[0079] Asphalt mixture rutting test, low-temperature bending test and freeze-thaw splitting test were used to evaluate the high-temperature stability, low-temperature crack resistance and water stability of asphalt mixtures modified by different modification processes.

[0080] Rutting test: T0719-2011 asphalt mixture rutting test in JTG E20-2011.

[0081] Bending test: T0715-2011 asphalt mixture bending test.

[0082] Thaw splitting test: T0729-2011 Freeze-thaw splitting test of asphalt mixture.

[0083] The high temperature stability, low temperature crack resistance and water stability of asphalt mixture modified by different modification processes were evaluated. Among them, the low temperature bending test was carried out using a PLD-100 electro-hydraulic servo fatigue testing machine. The test results are shown in Table 7.

[0084] Table 7 Performance indexes of modified asphalt mixture

[0085]

[0086]

[0087] It can be seen from the test results that the performance indicators of modified asphalt mixture 7 are all the lowest, with a dynamic stability of 6022mm, a bending stiffness modulus of 3013MPa, and a freeze-thaw splitting strength ratio of 86.7%, which are significantly lower than other mixtures, showing poor rutting resistance, rigidity and freeze-thaw resistance. The performance of other mixtures is relatively balanced, especially mixture 4, whose dynamic stability, bending stiffness modulus and freeze-thaw splitting strength ratio all reach the highest values, showing excellent comprehensive performance. Therefore, the performance of the modified asphalt mixture prepared using the modifier prepared by the present invention is significantly better and suitable for application scenarios with higher requirements.

[0088] 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 and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A "dry process" asphalt modifier for bridge deck paving, characterized in that: The invention comprises the following components in parts by weight: 50-70 parts of SBS, 1-5 parts of aluminum silicate, 5-10 parts of polyvinyl alcohol, 0.5-1 parts of zinc oxide and 20-35 parts of epoxy resin.

2. The asphalt modifier according to claim 1, characterized in that The composition comprises the following components in parts by weight: 60 parts of SBS, 5 parts of aluminum silicate, 8 parts of polyvinyl alcohol, 0.7 parts of zinc oxide and 30 parts of epoxy resin.

3. The asphalt modifier according to claim 1, characterized in that: The particle size of SBS is less than 2.5 mm; the particle size of other components is less than 100 μm.

4. A method for preparing the asphalt modifier according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1: using an impact mill to shear and grind the SBS for 1 to 3 minutes, and the particle size of the SBS particles after shearing is less than 1 mm; S2: premixing the aluminum silicate, polyvinyl alcohol, zinc oxide and epoxy resin and adding them into a ball mill, controlling the speed of the ball mill to be 60%-80% of the critical speed, and grinding for 100-120 minutes to prepare a mixed powder with a particle size of less than 100 microns; S3: Using a fluidized bed mixer, mix the SBS particles prepared in steps S1 and S2 with the mixed powder for 10-15 minutes to prepare an asphalt modifier.

5. A modified asphalt mixture for "dry process" bridge deck paving, characterized in that: In parts by weight, the raw materials include: 1-5 parts of the asphalt modifier according to any one of claims 1-3, 5-10 parts of base asphalt, and 100 parts of mineral material; the mineral material consists of aggregate and mineral powder.

6. A method for preparing the modified asphalt mixture according to claim 5, characterized in that: The following steps are involved: S1: mixing the asphalt modifier with aggregate at a temperature of 170-180° C. for 60-120 seconds to obtain a mixture 1; S2: Mixing the mixed mixture 1 with base asphalt at a mixing temperature of 170-180° C. for 60-120 seconds to obtain a mixture 2; S3: adding mineral powder to the mixture 2 and mixing the mixture for 60-120 seconds to obtain the asphalt mixture.

7. Use of the modified asphalt mixture according to claim 5 in the paving and repair of steel bridge decks, tunnels, airports, high-grade highways and urban trunk roads.

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