High-performance asphalt concrete for hydraulic engineering and preparation method of high-performance asphalt concrete

Abstract

The invention discloses high-performance asphalt concrete for hydraulic engineering and a preparation method thereof, and belongs to the field of asphalt concrete.The preparation method comprises the following steps that coarse aggregate, fine aggregate, filler and modified fiber are mixed and stirred for 2-4 min at the temperature of 160-175 DEG C, a dry material is obtained, then the obtained dry material and modified asphalt are mixed at the temperature of 170-180 DEG C, the stirring time is 3-6 min, discharging is performed, and the high-performance asphalt concrete for hydraulic engineering is obtained. And pouring the mixture into a mold for molding, demolding and curing to obtain the high-performance asphalt concrete. The obtained asphalt concrete has good tear resistance, toughness and high-temperature slope stability, meets the requirements of hydraulic anti-seepage structures in the fields of hydraulic engineering and the like, and is high in practicability.

Description

Technical Field

[0001] The present invention belongs to the field of asphalt concrete, and in particular relates to high-performance asphalt concrete for water conservancy projects and a preparation method thereof. Background Art

[0002] Asphalt concrete is increasingly used in my country's water conservancy projects due to its excellent anti-seepage performance, strong deformation capacity, and ability to be repaired promptly should problems arise. Its performance is gradually being recognized by the engineering community. In recent years, my country has independently completed the construction of asphalt concrete anti-seepage panels and asphalt concrete core walls. As the primary material for anti-seepage structures in hydraulic structures, the safety and stability of asphalt concrete are crucial. For example, Chinese patent CN114409311A discloses a high-performance asphalt concrete and its preparation method. The asphalt concrete is composed of asphalt, a strengthening agent, mineral powder, and acidic aggregate. The acidic aggregate is rich in polar components such as silica on its surface, exhibiting strong hydrophilicity. However, asphalt is a non-polar or weakly polar substance. The difficulty in forming effective adsorption between the two molecules can lead to a loose mixture structure, aggregate shedding, and insufficient slope stability at high temperatures. In high humidity environments, water intrusion can exacerbate interfacial delamination and accelerate aging. Furthermore, free calcium oxide and magnesium oxide may remain in the steel slag powder, which easily expands in volume upon contact with water, causing cracks or localized deformation over long-term use. Summary of the Invention

[0003] In order to solve the existing problems of easy deformation and breakage and high slope flow value, the present invention provides high-performance asphalt concrete for water conservancy projects and a preparation method thereof.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] High-performance asphalt concrete for water conservancy projects and a preparation method thereof, comprising the following steps:

[0006] Step 1: Prepare the following raw materials by weight: 36-46 parts of modified asphalt, 220-260 parts of coarse aggregate, 240-280 parts of fine aggregate, 60-80 parts of filler, and 1-4 parts of modified basalt fiber;

[0007] The second step is to mix the coarse aggregate, fine aggregate, filler and modified fiber, stir at 160℃-175℃ for 2-4 minutes to obtain dry material, then mix the obtained dry material with modified asphalt, discharge the material, pour it into a mold for molding, demould and cure it to obtain high-performance asphalt concrete.

[0008] Furthermore, the modified asphalt is prepared by the following steps:

[0009] Place the base asphalt, furfural extracted oil and layered dihydroxy composite metal hydroxide in an oil bath, stir at 140-160°C for 10-30 minutes, use a shear emulsifier to shear at a rate of 3000r / min for 60-80 minutes, then add cyclodextrin and continue shearing at a rate of 3000r / min for 5-10 minutes to obtain modified asphalt.

[0010] Furthermore, the mass ratio of the matrix asphalt, furfural extracted oil, layered bishydroxy composite metal hydroxide and cyclodextrin is 1:0.02-0.05:0.05-0.1:0.01-0.02. The layered bishydroxy composite metal hydroxide is Mg 1-X Al X (OH)2(CO3) X / 2·mH2O, subscript X represents the change of metal element content, 0.2≤X≤0.33, m represents the content of crystal water, 0≤m≤2.

[0011] Furthermore, the modified basalt fiber is prepared by the following steps:

[0012] S1. First, ultrasonically wash the basalt fiber in acetone to obtain washed basalt fiber. Then, add γ-aminopropyltriethoxysilane and 95% ethanol solution to the flask and soak for 30-60 minutes. Then, remove the soaked basalt fiber, react at 105-115°C for 2-4 hours, wash, and dry to obtain amino-treated basalt fiber.

[0013] In the above reaction, the usage ratio of acetone, basalt fiber, γ-aminopropyltriethoxysilane and 95% ethanol solution is 250 mL:20 g:20 mL:200-300 mL.

[0014] S2. Add maleic anhydride grafted SBS to toluene and swell for 1-2 days to obtain a swelling solution, place the amino basalt fiber in toluene and ultrasonically disperse it for 20-30 minutes, add the swelling solution, react at 90-110°C for 40-80 minutes, then add triethylamine, react at 105-115°C for 2-4 days, and dry to obtain modified basalt fiber.

[0015] In the above reaction, the amount ratio of maleic anhydride grafted SBS, amino basalt fiber and triethylamine is 2-5g:20g:1mL.

[0016] Furthermore, the coarse aggregate and the fine aggregate are both limestone.

[0017] Furthermore, the mixing temperature of the dry material and modified asphalt is 170° C.-180° C., and the stirring time is 3-6 minutes.

[0018] Beneficial effects of the present invention:

[0019] 1. Mix and stir coarse aggregate, fine aggregate, filler and modified fiber to obtain dry material, and then mix the dry material with modified asphalt. Both coarse aggregate and fine aggregate are limestone, which is alkaline aggregate rather than acidic aggregate. The obtained asphalt concrete has good tear resistance and toughness as well as high-temperature slope stability, which meets the needs of hydraulic anti-seepage structures in water conservancy projects and other fields and is highly practical.

[0020] 2. The present invention uses layered dihydroxy composite metal hydroxide (LDH) to adsorb polar components in asphalt through the positive charge between the layers to form an intercalation complex, thereby enhancing the cohesion between asphalt molecules and inhibiting high-temperature flow. Cyclodextrin encapsulates low molecular weight hydrocarbons in asphalt through hydrophobic cavities, inhibiting high-temperature volatilization and migration. Together with LDH, it forms an "intercalation-encapsulation" dual network, improving the high-temperature stability of asphalt concrete materials.

[0021] 3. The present invention grafts amino groups and Si-O-Si structures onto the surface of basalt fiber through chemical means, thereby improving its hydrophobicity, facilitating amidation reaction between amino groups and anhydride groups, forming covalent bonds, and significantly inhibiting interfacial peeling. Furfural extracted oil is rich in aromatic hydrocarbons, which can enhance the compatibility between asphalt and SBS, and can serve as a bridge to form a three-dimensional elastic network of "fiber-SBS-asphalt", thereby inhibiting the expansion of cracks. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] The fiber length of the present invention is 6-9 mm, the diameter is 10-15 μm, the tensile strength is 1500-3200 MPa, and the elastic modulus is 80-120 GPa;

[0024] Layered dihydroxy composite metal hydroxide was provided by Jiangyin Ruifa Chemical Co., Ltd.

[0025] Maleic anhydride-grafted SBS was provided by Yangzhou Henghui Chemical Co., Ltd.

[0026] Example 1

[0027] A modified asphalt is prepared by the following steps:

[0028] Put 2000g of base asphalt, 20g of furfural extracted oil and 50g of layered dihydroxy composite metal hydroxide into an oil bath, stir at 140°C for 10min, shear at a rate of 3000r / min for 60min using a shear emulsifier, then add 20g of cyclodextrin and continue shearing at a rate of 3000r / min for 5min to obtain modified asphalt.

[0029] Example 2

[0030] A modified asphalt is prepared by the following steps:

[0031] Put 2000g of base asphalt, 50g of furfural extracted oil and 100g of layered dihydroxy composite metal hydroxide into an oil bath, stir at 140-160℃ for 30min, shear at a rate of 3000r / min for 80min using a shear emulsifier, then add 20g of cyclodextrin and continue shearing at a rate of 3000r / min for 10min to obtain modified asphalt.

[0032] Example 3

[0033] A modified basalt fiber is prepared by the following steps:

[0034] S1. First, 20 g of basalt fiber was ultrasonically washed in 250 mL of acetone to obtain washed basalt fiber. Then, 20 mL of γ-aminopropyltriethoxysilane and 200 mL of 95% ethanol solution were added to the flask and immersed for 30 min. The immersed basalt fiber was taken out and reacted at 105°C for 2 h, washed, and dried to obtain amino-treated basalt fiber.

[0035] S2. Add 2 g of maleic anhydride-grafted SBS to 200 mL of toluene and swell for 1 day to obtain a swelling solution. Place 20 g of amino-modified basalt fiber in 400 mL of toluene and ultrasonically disperse it for 20 minutes. Add the swelling solution and react at 90°C for 40 minutes. Then add 1 mL of triethylamine and react at 105°C for 2 days. Dry and obtain modified basalt fiber.

[0036] Example 4

[0037] A modified basalt fiber is prepared by the following steps:

[0038] S1. First, 20 g of basalt fiber was ultrasonically washed in 250 mL of acetone to obtain washed basalt fiber. Then, 20 mL of γ-aminopropyltriethoxysilane and 300 mL of 95% ethanol solution were added to the flask and immersed for 60 min. The immersed basalt fiber was taken out and reacted at 115°C for 4 h, washed, and dried to obtain amino-treated basalt fiber.

[0039] S2. Add 5 g of maleic anhydride-grafted SBS to 200 mL of toluene and swell for 2 days to obtain a swelling solution. Place 20 g of amino-modified basalt fiber in 400 mL of toluene and ultrasonically disperse it for 30 minutes. Add the swelling solution and react at 110°C for 80 minutes. Then add 1 mL of triethylamine and react at 115°C for 4 days. Dry and obtain modified basalt fiber.

[0040] Example 5

[0041] A modified basalt fiber is prepared by the following steps:

[0042] S1. First, 20 g of basalt fiber was ultrasonically washed in 250 mL of acetone to obtain washed basalt fiber. Then, 20 mL of γ-aminopropyltriethoxysilane and 250 mL of 95% ethanol solution were added to the flask and immersed for 40 min. The immersed basalt fiber was taken out and reacted at 110°C for 3 h. After washing and drying, the amino-treated basalt fiber was obtained.

[0043] S2. Add 4 g of maleic anhydride-grafted SBS to 200 mL of toluene and swell for 1.5 days to obtain a swelling solution. Place 20 g of amino-modified basalt fiber in 400 mL of toluene and ultrasonically disperse it for 25 minutes. Add the swelling solution and react at 105°C for 60 minutes. Then add 1 mL of triethylamine and react at 110°C for 3 days. Dry and obtain modified basalt fiber.

[0044] Example 6

[0045] The method for preparing high-performance asphalt concrete for water conservancy projects comprises the following steps:

[0046] Step 1: Prepare the following raw materials by weight: 36 parts of modified asphalt, 220 parts of coarse aggregate, 240 parts of fine aggregate, 60 parts of filler, and 1 part of modified basalt fiber;

[0047] The second step is to mix the coarse aggregate, fine aggregate, filler and modified fiber, stir at 160℃ for 2 minutes to obtain dry material, and then mix the obtained dry material with modified asphalt at a mixing temperature of 170℃ and a stirring time of 6 minutes. Discharge the material, pour it into a mold for molding, demoulding, and curing to obtain high-performance asphalt concrete.

[0048] Example 7

[0049] Step 1: Prepare the following raw materials by weight: 46 parts of modified asphalt, 260 parts of coarse aggregate, 280 parts of fine aggregate, 80 parts of filler, and 4 parts of modified basalt fiber;

[0050] The second step is to mix the coarse aggregate, fine aggregate, filler and modified fiber, stir at 175℃ for 4 minutes to obtain dry material, and then mix the obtained dry material with modified asphalt at a mixing temperature of 180℃ and a stirring time of 6 minutes. Discharge the material, pour it into a mold for molding, demould and cure to obtain high-performance asphalt concrete.

[0051] Example 8

[0052] Step 1: Prepare the following raw materials by weight: 40 parts of modified asphalt, 240 parts of coarse aggregate, 260 parts of fine aggregate, 74 parts of filler, and 2 parts of modified basalt fiber;

[0053] The second step is to mix the coarse aggregate, fine aggregate, filler and modified fiber, stir at 165℃ for 3 minutes to obtain dry material, and then mix the obtained dry material with modified asphalt at a mixing temperature of 175℃ and a stirring time of 5 minutes. Discharge the material, pour it into a mold for molding, demoulding, and curing to obtain high-performance asphalt concrete.

[0054] Comparative Example 1

[0055] Compared with Example 8, the "modified asphalt" in Example 8 is replaced by "base asphalt", and the remaining raw materials and preparation process are the same as Example 8.

[0056] Comparative Example 2

[0057] Compared with Example 8, the “modified basalt fiber” in Example 8 is replaced by “basalt fiber”, and the remaining raw materials and preparation process are the same as Example 8.

[0058] Comparative Example 3

[0059] Compared with Example 8, the "modified asphalt" and "modified basalt fiber" in Example 8 are replaced by "matrix asphalt" and "basalt fiber", and the remaining raw materials and preparation process are the same as Example 8.

[0060] Performance tests were performed on the results of Examples 6 to 8 and Comparative Examples 1 to 2. The asphalt concrete was subjected to a slope flow test in accordance with the "Test Procedure for Hydraulic Asphalt Concrete" DL / T5362-2018. The test temperature was 80°C, and the slope flow value was detected after 48 hours.

[0061] Asphalt concrete was made into specimens with a diameter of 100 mm and a height of 60 mm, and placed at a temperature of -20°C for 7 days. Then the splitting performance and compressive resistance of the asphalt concrete were tested according to the method of JTJ052-2000.

[0062] According to the "Test Procedures for Hydraulic Asphalt Concrete" DL / T5362-2018, the asphalt concrete was subjected to a freeze-break test with the test conditions of 30℃ / h to detect the freeze-break temperature.

[0063] The test results are shown in Table 1:

[0064] Table 1

[0065]

[0066] It can be seen from Table 1 that, compared with comparative examples 1-3, the slope flow value of the asphalt concrete of Examples 6-8 is 0.583-0.762 mm, and the stability of the examples at high temperatures is higher; the splitting strength of the asphalt concrete of Examples 6-8 is 4.32-4.84 MPa, the compressive strength is 10.26-11.84 MPa, and the freezing temperature is minus 55.62-minus 53.28, and the examples have better crack resistance and toughness at low temperatures.

[0067] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0068] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing high-performance asphalt concrete for water conservancy projects, characterized in that: The following steps are involved: Step 1: Prepare the following raw materials by weight: 36-46 parts of modified asphalt, 220-260 parts of coarse aggregate, 240-280 parts of fine aggregate, 60-80 parts of filler, and 1-4 parts of modified basalt fiber; The second step is to mix the coarse aggregate, fine aggregate, filler and modified fiber, stir at 160℃-180℃ for 2-4 minutes to obtain dry material, then mix the obtained dry material with modified asphalt, discharge the material, pour it into a mold for molding, demould and cure to obtain high-performance asphalt concrete.

2. The method for preparing high-performance asphalt concrete for water conservancy projects according to claim 1, characterized in that: Modified asphalt is made through the following steps: Place the base asphalt, furfural extracted oil and layered dihydroxy composite metal hydroxide in an oil bath, stir at 140-160°C for 10-30 minutes, use a shear emulsifier to shear at a rate of 3000r / min for 60-80 minutes, then add cyclodextrin and continue shearing at a rate of 3000r / min for 5-10 minutes to obtain modified asphalt.

3. The method for preparing high-performance asphalt concrete for water conservancy projects according to claim 2, characterized in that: The mass ratio of the matrix asphalt, furfural extracted oil, layered bishydroxy composite metal hydroxide and cyclodextrin is 1:0.02-0.05:0.05-0.1:0.01-0.02, and the layered bishydroxy composite metal hydroxide is Mg 1-X A l X (OH)2(CO3) X / 2·mH2O, subscript X represents the change of metal element content, 0.2≤X≤0.33, m represents the content of crystal water, 0≤m≤2.

4. The method for preparing high-performance asphalt concrete for water conservancy projects according to claim 1, characterized in that: Modified basalt fiber is made by the following steps: S1. First, ultrasonically wash the basalt fiber in acetone to obtain washed basalt. Then, add γ-aminopropyltriethoxysilane and 95% ethanol solution to the flask and soak for 30-60 minutes. Then, remove the soaked basalt fiber, react at 105-115°C for 2-4 hours, wash, and dry to obtain amino-treated basalt fiber. S2. Add maleic anhydride grafted SBS to toluene and swell for 1-2 days to obtain a swelling solution, place the amino basalt fiber in toluene and ultrasonically disperse it for 20-30 minutes, add the swelling solution, react at 90-110°C for 40-80 minutes, then add triethylamine, react at 105-115°C for 2-4 days, and dry to obtain modified basalt fiber.

5. The method for preparing high-performance asphalt concrete for water conservancy projects according to claim 4, characterized in that: The amount ratio of maleic anhydride grafted SBS, amino basalt fiber and triethylamine in S2 is 2-5g:20g:1mL.

6. The method for preparing high-performance asphalt concrete for water conservancy projects according to claim 1, characterized in that: The coarse aggregate and the fine aggregate are both limestone; the particle size of the coarse aggregate is 2.5-16 mm, and the particle size of the fine aggregate is 0.15-2.5 mm.

7. The method for preparing high-performance asphalt concrete for water conservancy projects according to claim 1, characterized in that: The mixing temperature of the dry material and modified asphalt is 170-180° C., and the stirring time is 3-6 minutes.

8. A high-performance asphalt concrete for water conservancy projects, characterized in that: Prepared by the preparation method according to any one of claims 1 to 7.

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