A crack-resistant asphalt concrete material and preparation method thereof

Abstract

The present invention relates to the technical field of asphalt concrete, and discloses a crack-resistant asphalt concrete material and a preparation method thereof. The asphalt concrete material in the present application significantly improves the crack resistance, service life, and UV aging resistance of the matrix by adding reinforcing fillers and composite aerogels. The reinforcing fillers are based on the synergistic effect between modified lignin, diatomaceous earth, and hydrotalcite, and a silane coupling agent is used to improve the compatibility between them, thereby increasing the dispersibility of the reinforcing fillers in the matrix, thereby improving the crack resistance, service life, and UV resistance of the matrix. The composite aerogel has excellent thermal insulation properties and a three-dimensional network structure, which can synergistically improve the crack resistance of the matrix.

Description

Technical Field

[0001] The present invention relates to the technical field of asphalt concrete, and in particular to an anti-cracking asphalt concrete material and a preparation method thereof. Background Art

[0002] Asphalt concrete is a composite material used in road construction. It is mainly composed of asphalt, aggregate, filler and various additives. It has the advantages of good adhesion, strong adaptability, convenient construction, low maintenance cost and good environmental adaptability. Therefore, it can be widely used in the construction of transportation infrastructure such as roads, airport runways, and parking lots. It is one of the indispensable materials for modern transportation construction.

[0003] However, it is difficult to prepare ideal asphalt concrete when preparing it. Asphalt concrete generally has shortcomings such as easy cracking, poor low-temperature resistance, and poor UV aging resistance, which greatly reduces the service life of asphalt concrete pavements. To address the cracking problem of asphalt concrete materials, fiber materials (such as polypropylene fiber, plant fiber, glass fiber, etc.), rubber powder, and polymer modifiers are generally added to improve the crack resistance of asphalt concrete, but the crack resistance effect is limited. Therefore, researchers need to develop an asphalt concrete material with excellent crack resistance, UV resistance, and service life. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a crack-resistant asphalt concrete material and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A crack-resistant asphalt concrete material comprises the following raw materials in parts by weight: 8-16 parts asphalt, 60-80 parts coarse aggregate, 25-45 parts fine aggregate, 5-9 parts fly ash, 5-12 parts reinforcing filler, and 3-7 parts composite aerogel;

[0007] The reinforcing filler is prepared by the following steps:

[0008] Step A1: Mix methacrylic acid and 1,6-heptadien-4-ol and stir them evenly, add 98 wt% concentrated sulfuric acid, and heat to 60-80° C., react at a pressure of 0.2-0.3 MPa for 2.5-4.5 hours, and distill under reduced pressure, cool, and filter to obtain diene methacrylate;

[0009] Step A2: Calcium chloride is evenly dispersed in dimethyl sulfoxide, and the enzymatically hydrolyzed lignin is added and stirred for 10 minutes. The mixture is ultrasonically treated for 15 minutes, and then diene methacrylate and 30 wt% hydrogen peroxide are slowly added. The temperature is raised to 35-45° C. and stirred for 16-24 hours. Deionized water is then added and stirred for 10-20 minutes. The mixture is filtered, washed, and dried to obtain terminal double-bond lignin.

[0010] Step A3: Disperse the double-bond-terminated lignin uniformly in tetrahydrofuran under nitrogen, then slowly introduce hydrogen sulfide gas, react at 45-55° C. for 1-2 days, filter, wash, and dry to obtain modified lignin;

[0011] Step A4: The modified lignin, diatomaceous earth, and hydrotalcite are mixed and ground, and then a silane coupling agent, deionized water, and ethanol are added. The mixture is stirred at 35-45° C. for 2-4 hours, allowed to stand for 2 hours, filtered, and dried to obtain a reinforcing filler.

[0012] Furthermore, in step A1, the ratio of methacrylic acid, 1,6-heptadien-4-ol and concentrated sulfuric acid is 0.1-0.2 mol: 0.105-0.021 mol: 0.43-0.86 g;

[0013] Furthermore, in step A2, the ratio of calcium chloride, dimethyl sulfoxide, enzymatic lignin, diene methacrylate, hydrogen peroxide and deionized water is 3.1-6.2 g: 200 mL: 5-10 g: 0.012-0.024 mol: 1.5-3 g: 200 mL;

[0014] Furthermore, in step A3, the ratio of terminal double bond lignin to tetrahydrofuran is 0.5-2 g: 20 mL;

[0015] Furthermore, in step A4, the ratio of modified lignin, diatomaceous earth, hydrotalcite, silane coupling agent, deionized water and ethanol is 20-50 g: 5-15 g: 5-10 g: 2-5 g: 20 mL: 180 mL;

[0016] Furthermore, the silane coupling agent in step A4 is one of KH550, KH560 or KH570.

[0017] The composite aerogel is prepared by the following steps:

[0018] Step B1, slowly add the 2,4-dihydroxybenzophenone solution to the acryloyl chloride solution in an ice-water bath and stir continuously for 5-10 minutes, then warm to room temperature and react with stirring for 4-6 hours, then add deionized water for washing, separate the liquid, rotary evaporate to 50 mL, then add methanol and stir for 10 minutes, then rotary evaporate to 50 mL, let stand for 24 hours, filter, redisperse the filter cake in dichloromethane, then add petroleum ether and stir vigorously for 10-20 minutes, filter, and dry to obtain a terminal double bond product;

[0019] Step B2: Under nitrogen, KH550 was evenly dispersed in methanol, and the terminal double bond product was slowly added and stirred at room temperature for 30 minutes. Then, the mixture was kept in a 25°C oil bath for 3.5-4.5 hours and distilled under reduced pressure to obtain the grafted modified silane.

[0020] Step B3, dispersing the grafted modified silane and KH550 in ethanol, recorded as solution A; dispersing tetraethyl orthosilicate in ethanol, and adjusting the pH of the solution to 2-3, slowly adding solution A dropwise, stirring at room temperature for 8-12 hours, adjusting the pH of the system to 7-8, vigorously stirring for 5-10 minutes, transferring to a mold and letting it stand to form a gel, then aging for 12 hours, washing, and freeze-drying to obtain a composite aerogel;

[0021] Furthermore, in step B1, the usage ratio of acryloyl chloride solution, 2,4-dihydroxybenzophenone solution, deionized water, methanol, dichloromethane and petroleum ether is 100 mL: 100 mL: 200 mL: 50 mL: 50 mL: 200 mL;

[0022] Furthermore, in step B1, the acryloyl chloride solution is prepared by mixing acryloyl chloride and dichloromethane in a ratio of 0.1-0.3 mol:100 mL, and the 2,4-dihydroxybenzophenone solution is prepared by mixing 2,4-dihydroxybenzophenone, triethylamine and dichloromethane in a ratio of 0.05-0.2 mol:0.1-0.3 mol:100 mL;

[0023] Furthermore, in step B2, the ratio of KH550, methanol, and terminal double bond product is 4.68-9.37 mL:10 mL:5.6-11.2 g;

[0024] Furthermore, in step B3, the ratio of tetraethyl orthosilicate, ethanol, and solution A is 11-22 mL: 20 mL: 20 mL;

[0025] Furthermore, the usage ratio of the grafted modified silane, KH550 and ethanol in solution A of step B3 is 3-6 g: 1.5-2.5 mL: 20 mL.

[0026] A method for preparing a crack-resistant asphalt concrete material comprises the following steps:

[0027] Step S1, weighing raw materials by weight, mixing and stirring coarse aggregate, fine aggregate, fly ash and reinforcing filler to obtain a mixed dry material;

[0028] Step S2: heating the asphalt to 140-170° C., stirring continuously, and sequentially adding the mixed dry materials and the composite aerogel, and mixing them evenly to obtain the anti-cracking asphalt concrete material.

[0029] Beneficial effects of the present invention:

[0030] The asphalt concrete material in this application significantly improves the crack resistance, service life and UV aging resistance of the matrix by adding reinforcing fillers and composite aerogels; wherein, the reinforcing fillers are based on the synergistic effect between modified lignin, diatomaceous earth and hydrotalcite, and the silane coupling agent is used to improve the compatibility between each other, thereby improving the dispersion of the reinforcing fillers in the matrix, thereby improving the crack resistance, service life and UV resistance of the matrix; the composite aerogel has excellent thermal insulation properties and a three-dimensional network structure, which can synergistically improve the crack resistance of the matrix.

[0031] In the reinforcing filler, methacrylic acid and 1,6-heptadien-4-ol are firstly used to synthesize diene methacrylate by esterification reaction; diene methacrylate is then used to undergo free radical copolymerization reaction with enzymatic lignin to obtain terminal double-bond lignin; the double bonds in the terminal double-bond lignin are then reacted with hydrogen sulfide gas to obtain modified lignin containing thiol groups; finally, the modified lignin, diatomaceous earth and hydrotalcite are mixed and ground, and cross-linked using a silane coupling agent to obtain a reinforcing filler. The reinforcing filler is based on the synergistic effect between modified lignin, diatomaceous earth and hydrotalcite, and the silane coupling agent is used to improve the compatibility between them, improve the dispersion of the reinforcing filler in the matrix, and thus improve the matrix's crack resistance, service life and UV resistance; among them, the modified lignin can use its fiber characteristics to play a reinforcing role in the matrix, improve the shear strength and compressive strength of the asphalt concrete material, and reduce the generation and expansion of cracks; the modified lignin also contains a large number of thiol groups, which can chelate metal ions in the matrix (such as Fe 3+ , Ca 2+ Mg 2+ The diatomaceous earth and hydrotalcite both have high specific surface area and porosity, and can effectively absorb harmful substances in asphalt concrete, reduce the aging and deterioration of asphalt, and thus reduce the occurrence of problems such as cracking and deformation. In addition, the reinforcing filler in the matrix can also improve the matrix's resistance to UV aging through physical shielding, thereby reducing cracking and spalling of asphalt concrete materials.

[0032] In the composite aerogel, acryloyl chloride and 2,4-dihydroxybenzophenone react to produce a terminal double-bond product. This terminal double-bond product then reacts with KH550 to produce a grafted modified silane. Finally, the grafted modified silane, KH550, and tetraethyl orthosilicate are used as raw materials to synthesize the composite aerogel. The composite aerogel significantly improves the thermal insulation of the matrix, reducing the thermal expansion and contraction of asphalt concrete during temperature fluctuations, thereby reducing cracks caused by thermal stress. The aerogel's three-dimensional network structure also enhances the matrix's toughness, making it resistant to cracking under external forces, further improving the matrix's crack resistance. Furthermore, the aerogel incorporates a UV-absorbing benzophenone structure, which reduces cracking in the matrix caused by UV aging. DETAILED DESCRIPTION

[0033] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0034] Example 1: The reinforcing filler is prepared by the following steps:

[0035] Step A1: 0.1 mol of methacrylic acid and 0.105 mol of 1,6-heptadien-4-ol were mixed and stirred uniformly, 0.43 g of 98 wt% concentrated sulfuric acid was added, and the temperature was raised to 60° C., and the reaction was carried out under a pressure of 0.2 MPa for 2.5 hours. The mixture was then distilled under reduced pressure, cooled, and filtered to obtain diene methacrylate;

[0036] Step A2: 3.1 g of calcium chloride was evenly dispersed in 200 mL of dimethyl sulfoxide, 5 g of enzymatic lignin was added, stirred for 10 min, and ultrasonicated for 15 min. Then, 0.012 mol of diene methacrylate and 1.5 g of 30 wt% hydrogen peroxide were slowly added, and the temperature was raised to 35° C. and stirred for 16 h. Then, 200 mL of deionized water was added and stirred for 10 min. The mixture was filtered, washed, and dried to obtain terminal double-bond lignin.

[0037] Step A3: Under nitrogen, 0.5 g of double-bond-terminated lignin was evenly dispersed in 20 mL of tetrahydrofuran, and hydrogen sulfide gas was slowly introduced. The mixture was reacted at 45° C. for 1 day, filtered, washed, and dried to obtain modified lignin.

[0038] Step A4: 20 g of modified lignin, 5 g of diatomaceous earth, and 5 g of hydrotalcite were mixed and ground, and then 2 g of silane coupling agent KH550, 20 mL of deionized water, and 180 mL of ethanol were added. The mixture was stirred at 35° C. for 2 h, allowed to stand for 2 h, filtered, and dried to obtain a reinforced filler.

[0039] Composite aerogels are prepared by the following steps:

[0040] Step B1, 100 mL of acryloyl chloride solution was slowly added to 100 mL of 2,4-dihydroxybenzophenone solution in an ice-water bath, and stirred continuously for 10 minutes, then heated to room temperature, stirred and reacted for 6 hours, and then 200 mL of deionized water was added for washing and separation, rotary evaporated to 50 mL, and then 50 mL of methanol was added and stirred for 10 minutes, and then rotary evaporated to 50 mL, allowed to stand for 24 hours, filtered, and the filter cake was redispersed in 50 mL of dichloromethane, and then 200 mL of petroleum ether was added and vigorously stirred for 20 minutes, filtered, and dried to obtain a terminal double bond product. The acryloyl chloride solution was prepared by mixing acryloyl chloride and dichloromethane in a ratio of 0.3 mol: 100 mL, and the 2,4-dihydroxybenzophenone solution was prepared by mixing 2,4-dihydroxybenzophenone, triethylamine and dichloromethane in a ratio of 0.2 mol: 0.3 mol: 100 mL;

[0041] Step B2: Under nitrogen, 9.37 mL of KH550 was evenly dispersed in 10 mL of methanol, 11.2 g of the terminal double bond product was slowly added, and stirred at room temperature for 30 min. The mixture was then kept in an oil bath at 25° C. for 4.5 h, and distilled under reduced pressure to obtain the grafted modified silane.

[0042] Step B3, 6 g of grafted modified silane and 2.5 mL of KH550 were dispersed in 20 mL of ethanol, recorded as solution A; 22 mL of tetraethyl orthosilicate was dispersed in 20 mL of ethanol, and the pH of the solution was adjusted to 3, 20 mL of solution A was slowly added dropwise, stirred at room temperature for 12 h, the pH of the system was adjusted to 8, and after vigorous stirring for 10 min, transferred to a mold and allowed to stand to form a gel, then aged for 12 h, washed, and freeze-dried to obtain a composite aerogel.

[0043] Example 2: The reinforcing filler is prepared by the following steps:

[0044] Step A1: 0.15 mol of methacrylic acid and 0.16 mol of 1,6-heptadien-4-ol were mixed and stirred uniformly, 0.65 g of 98 wt% concentrated sulfuric acid was added, and the temperature was raised to 70° C. The mixture was reacted at a pressure of 0.25 MPa for 3.5 hours, and the mixture was distilled under reduced pressure, cooled, and filtered to obtain diene methacrylate;

[0045] Step A2: 4.7 g of calcium chloride was evenly dispersed in 200 mL of dimethyl sulfoxide, 7.5 g of enzymatic lignin was added, stirred for 10 min, and ultrasonicated for 15 min. Then, 0.018 mol of diene methacrylate and 2.2 g of 30 wt% hydrogen peroxide were slowly added, and the temperature was raised to 40° C. and stirred for 20 h. Then, 200 mL of deionized water was added and stirred for 15 min. The mixture was filtered, washed, and dried to obtain terminal double-bond lignin.

[0046] Step A3: Under nitrogen, 1.2 g of double-bond-terminated lignin was evenly dispersed in 20 mL of tetrahydrofuran, and hydrogen sulfide gas was slowly introduced. The mixture was reacted at 50° C. for 1.5 days, filtered, washed, and dried to obtain modified lignin.

[0047] Step A4: 35 g of modified lignin, 10 g of diatomaceous earth, and 7.5 g of hydrotalcite were mixed and ground, and then 3.5 g of silane coupling agent KH560, 20 mL of deionized water, and 180 mL of ethanol were added. The mixture was stirred at 40° C. for 3 h, allowed to stand for 2 h, filtered, and dried to obtain a reinforced filler.

[0048] Composite aerogels are prepared by the following steps:

[0049] Step B1, 100 mL of acryloyl chloride solution was slowly added to 100 mL of 2,4-dihydroxybenzophenone solution in an ice-water bath, and stirred continuously for 7 minutes, then heated to room temperature, stirred and reacted for 5 hours, and then 200 mL of deionized water was added for washing and separation, rotary evaporated to 50 mL, and then 50 mL of methanol was added and stirred for 10 minutes, and then rotary evaporated to 50 mL, allowed to stand for 24 hours, filtered, and the filter cake was redispersed in 50 mL of dichloromethane, and then 200 mL of petroleum ether was added and vigorously stirred for 15 minutes, filtered, and dried to obtain a terminal double bond product. The acryloyl chloride solution was prepared by mixing acryloyl chloride and dichloromethane in a ratio of 0.2 mol: 100 mL, and the 2,4-dihydroxybenzophenone solution was prepared by mixing 2,4-dihydroxybenzophenone, triethylamine and dichloromethane in a ratio of 0.1 mol: 0.2 mol: 100 mL;

[0050] Step B2: Under nitrogen, 7.02 mL of KH550 was evenly dispersed in 10 mL of methanol, 8.4 g of the double-bond-terminated product was slowly added, and stirred at room temperature for 30 min. The mixture was then kept in an oil bath at 25° C. for 4 h, and distilled under reduced pressure to obtain the grafted modified silane.

[0051] Step B3, 4.5 g of grafted modified silane and 2 mL of KH550 were dispersed in 20 mL of ethanol, recorded as solution A; 16.5 mL of tetraethyl orthosilicate was dispersed in 20 mL of ethanol, and the pH of the solution was adjusted to 2.5, 20 mL of solution A was slowly added dropwise, stirred at room temperature for 10 h, the pH of the system was adjusted to 7.5, and after vigorous stirring for 7 min, it was transferred to a mold and allowed to stand to form a gel, then aged for 12 h, washed, and freeze-dried to obtain a composite aerogel.

[0052] Example 3: Reinforced filler is prepared by the following steps:

[0053] Step A1: 0.2 mol of methacrylic acid and 0.021 mol of 1,6-heptadien-4-ol were mixed and stirred uniformly, 0.86 g of 98 wt% concentrated sulfuric acid was added, and the temperature was raised to 80° C. The mixture was reacted at a pressure of 0.3 MPa for 4.5 hours, and vacuum distilled, cooled, and filtered to obtain diene methacrylate;

[0054] Step A2: 6.2 g of calcium chloride was evenly dispersed in 200 mL of dimethyl sulfoxide, 10 g of enzymatic lignin was added, stirred for 10 minutes, and ultrasonicated for 15 minutes. Then, 0.024 mol of diene methacrylate and 3 g of 30 wt% hydrogen peroxide were slowly added, and the temperature was raised to 45° C. and stirred for 24 hours. Then, 200 mL of deionized water was added and stirred for 20 minutes. The mixture was filtered, washed, and dried to obtain terminal double-bond lignin.

[0055] Step A3: Under nitrogen, 2 g of double-bond-terminated lignin was evenly dispersed in 20 mL of tetrahydrofuran, and hydrogen sulfide gas was slowly introduced. The mixture was reacted at 55° C. for 2 days, filtered, washed, and dried to obtain modified lignin.

[0056] Step A4: 50 g of modified lignin, 15 g of diatomaceous earth, and 10 g of hydrotalcite were mixed and ground, and then 5 g of silane coupling agent KH570, 20 mL of deionized water, and 180 mL of ethanol were added. The mixture was stirred at 45° C. for 4 h, allowed to stand for 2 h, filtered, and dried to obtain a reinforced filler.

[0057] Composite aerogels are prepared by the following steps:

[0058] Step B1, 100 mL of acryloyl chloride solution was slowly added to 100 mL of 2,4-dihydroxybenzophenone solution in an ice-water bath, and stirred continuously for 10 minutes, then heated to room temperature, stirred and reacted for 6 hours, and then 200 mL of deionized water was added for washing and separation, rotary evaporated to 50 mL, and then 50 mL of methanol was added and stirred for 10 minutes, and then rotary evaporated to 50 mL, allowed to stand for 24 hours, filtered, and the filter cake was redispersed in 50 mL of dichloromethane, and then 200 mL of petroleum ether was added and vigorously stirred for 20 minutes, filtered, and dried to obtain a terminal double bond product. The acryloyl chloride solution was prepared by mixing acryloyl chloride and dichloromethane in a ratio of 0.3 mol: 100 mL, and the 2,4-dihydroxybenzophenone solution was prepared by mixing 2,4-dihydroxybenzophenone, triethylamine and dichloromethane in a ratio of 0.2 mol: 0.3 mol: 100 mL;

[0059] Step B2: Under nitrogen, 9.37 mL of KH550 was evenly dispersed in 10 mL of methanol, 11.2 g of the terminal double bond product was slowly added, and stirred at room temperature for 30 min. The mixture was then kept in an oil bath at 25° C. for 4.5 h, and distilled under reduced pressure to obtain the grafted modified silane.

[0060] Step B3, 6 g of grafted modified silane and 2.5 mL of KH550 were dispersed in 20 mL of ethanol, recorded as solution A; 22 mL of tetraethyl orthosilicate was dispersed in 20 mL of ethanol, and the pH of the solution was adjusted to 3, 20 mL of solution A was slowly added dropwise, stirred at room temperature for 12 h, the pH of the system was adjusted to 8, and after vigorous stirring for 10 min, transferred to a mold and allowed to stand to form a gel, then aged for 12 h, washed, and freeze-dried to obtain a composite aerogel.

[0061] Example 4: A method for preparing a crack-resistant asphalt concrete material comprises the following steps:

[0062] 8 parts of asphalt, 60 parts of coarse aggregate, 25 parts of fine aggregate, 5 parts of fly ash, 5 parts of the reinforcing filler prepared in Example 1, and 3 parts of the composite aerogel prepared in Example 1;

[0063] Step S1, weighing raw materials by weight, mixing and stirring the coarse aggregate, fine aggregate, fly ash and the reinforcing filler prepared in Example 1 to obtain a mixed dry material;

[0064] Step S2: heating the asphalt to 140° C., stirring continuously, and sequentially adding the mixed dry materials and the composite aerogel prepared in Example 1, and mixing them evenly to obtain the crack-resistant asphalt concrete material.

[0065] Example 5: A method for preparing a crack-resistant asphalt concrete material comprises the following steps:

[0066] 12 parts of asphalt, 70 parts of coarse aggregate, 35 parts of fine aggregate, 7 parts of fly ash, 8 parts of the reinforcing filler prepared in Example 2, and 5 parts of the composite aerogel prepared in Example 2;

[0067] Step S1, weighing raw materials by weight, mixing and stirring the coarse aggregate, fine aggregate, fly ash and the reinforcing filler prepared in Example 2 to obtain a mixed dry material;

[0068] Step S2: heating the asphalt to 155° C., stirring continuously, and sequentially adding the mixed dry materials and the composite aerogel prepared in Example 2, and mixing them evenly to obtain the crack-resistant asphalt concrete material.

[0069] Example 6: A method for preparing a crack-resistant asphalt concrete material comprises the following steps:

[0070] 16 parts of asphalt, 80 parts of coarse aggregate, 45 parts of fine aggregate, 9 parts of fly ash, 12 parts of the reinforcing filler prepared in Example 3, and 7 parts of the composite aerogel prepared in Example 3;

[0071] Step S1, weighing raw materials by weight, mixing and stirring the coarse aggregate, fine aggregate, fly ash and the reinforcing filler prepared in Example 3 to obtain a mixed dry material;

[0072] Step S2: Heat the asphalt to 170° C., continue stirring, and sequentially add the mixed dry materials and the composite aerogel prepared in Example 3, and mix them evenly to obtain the crack-resistant asphalt concrete material.

[0073] Comparative Example 1: This comparative example is an asphalt concrete material. The difference from Example 5 is that diatomaceous earth is used instead of the reinforcing filler prepared in Example 2, and the rest are the same.

[0074] Comparative Example 2: This comparative example is an asphalt concrete material. The difference from Example 5 is that silica aerogel is used instead of the composite aerogel prepared in Example 2, and the rest are the same.

[0075] The asphalt concrete materials prepared in Examples 4-6 and Comparative Examples 1-2 were poured into a mold, compacted at 2.0 MPa, and naturally cured for 7 days. Samples were taken according to the JTG E20-2011 standard and subjected to Marshall stability test, rutting test, and freeze-thaw splitting test for performance testing. The cured samples were placed in a UV aging box with an ultraviolet intensity of 210 W / m 2 The aging temperature is 60℃, the aging time is 6 days, and then the freeze-thaw splitting test is carried out. The test results are shown in Table 1:

[0076] Table 1: Performance test results

[0077]

[0078] As can be seen from Table 1, the asphalt concrete material prepared by the present invention, after Marshall stability test, rutting test and freeze-thaw splitting test, has a Marshall stability in the range of (10.76-11.69) kN, a dynamic stability in the range of (6734-7021) times / mm, and a freeze-thaw splitting residual strength ratio in the range of (92.24-94.68)%, indicating that the asphalt concrete material has excellent crack resistance, UV resistance and service life.

[0079] The above content is merely an example and explanation of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the scope defined by the concept of the invention, they should all fall within the scope of protection of the present invention.

Claims

1. A crack-resistant asphalt concrete material, characterized in that: The material comprises the following raw materials in parts by weight: 8-16 parts of asphalt, 60-80 parts of coarse aggregate, 25-45 parts of fine aggregate, 5-9 parts of fly ash, 5-12 parts of reinforcing filler, and 3-7 parts of composite aerogel; The reinforcing filler is prepared by the following steps: Step A1: Mix methacrylic acid and 1,6-heptadien-4-ol and stir them evenly, add 98 wt% concentrated sulfuric acid, and heat to 60-80° C., react at a pressure of 0.2-0.3 MPa for 2.5-4.5 hours, and distill under reduced pressure, cool, and filter to obtain diene methacrylate; Step A2: Calcium chloride is evenly dispersed in dimethyl sulfoxide, and the enzymatically hydrolyzed lignin is added and stirred for 10 minutes. The mixture is ultrasonically treated for 15 minutes, and then diene methacrylate and 30 wt% hydrogen peroxide are slowly added. The temperature is raised to 35-45° C. and stirred for 16-24 hours. Deionized water is then added and stirred for 10-20 minutes. The mixture is filtered, washed, and dried to obtain terminal double-bond lignin. Step A3: Disperse the double-bond-terminated lignin uniformly in tetrahydrofuran under nitrogen, then slowly introduce hydrogen sulfide gas, react at 45-55° C. for 1-2 days, filter, wash, and dry to obtain modified lignin; Step A4: The modified lignin, diatomaceous earth, and hydrotalcite are mixed and ground, and then a silane coupling agent, deionized water, and ethanol are added. The mixture is stirred at 35-45° C. for 2-4 hours, allowed to stand for 2 hours, filtered, and dried to obtain a reinforcing filler. The composite aerogel is prepared by the following steps: Step B1, slowly add the 2,4-dihydroxybenzophenone solution to the acryloyl chloride solution in an ice-water bath and stir continuously for 5-10 minutes, then warm to room temperature and react with stirring for 4-6 hours, then add deionized water for washing, separate the liquid, rotary evaporate to 50 mL, then add methanol and stir for 10 minutes, then rotary evaporate to 50 mL, let stand for 24 hours, filter, redisperse the filter cake in dichloromethane, then add petroleum ether and stir vigorously for 10-20 minutes, filter, and dry to obtain a terminal double bond product; Step B2: Under nitrogen, KH550 was evenly dispersed in methanol, and the terminal double bond product was slowly added and stirred at room temperature for 30 minutes. Then, the mixture was kept in a 25°C oil bath for 3.5-4.5 hours and distilled under reduced pressure to obtain the grafted modified silane. Step B3, dispersing the grafted modified silane and KH550 in ethanol, recorded as solution A; dispersing tetraethyl orthosilicate in ethanol, and adjusting the pH of the solution to 2-3, slowly adding solution A dropwise, stirring at room temperature for 8-12 hours, adjusting the pH of the system to 7-8, vigorously stirring for 5-10 minutes, transferring to a mold and letting it stand to form a gel, then aging for 12 hours, washing, and freeze-drying to obtain a composite aerogel.

2. The anti-cracking asphalt concrete material according to claim 1, characterized in that: In step A1, the usage ratio of methacrylic acid, 1,6-heptadien-4-ol and concentrated sulfuric acid is 0.1-0.2 mol: 0.105-0.021 mol: 0.43-0.86 g.

3. The anti-cracking asphalt concrete material according to claim 1, characterized in that: In step A2, the usage ratio of calcium chloride, dimethyl sulfoxide, enzymatically hydrolyzed lignin, diene methacrylate, hydrogen peroxide and deionized water is 3.1-6.2 g: 200 mL: 5-10 g: 0.012-0.024 mol: 1.5-3 g: 200 mL.

4. The anti-cracking asphalt concrete material according to claim 1, characterized in that: In step A3, the usage ratio of terminal double bond lignin and tetrahydrofuran is 0.5-2 g:20 mL.

5. The anti-cracking asphalt concrete material according to claim 1, characterized in that: In step A4, the usage ratio of modified lignin, diatomaceous earth, hydrotalcite, silane coupling agent, deionized water and ethanol is 20-50 g: 5-15 g: 5-10 g: 2-5 g: 20 mL: 180 mL.

6. The anti-cracking asphalt concrete material according to claim 1, characterized in that: In step B1, the amount ratio of acryloyl chloride solution, 2,4-dihydroxybenzophenone solution, deionized water, methanol, dichloromethane and petroleum ether is 100 mL: 100 mL: 200 mL: 50 mL: 50 mL: 200 mL, the acryloyl chloride solution is prepared by mixing acryloyl chloride and dichloromethane in a ratio of 0.1-0.3 mol: 100 mL, and the 2,4-dihydroxybenzophenone solution is prepared by mixing 2,4-dihydroxybenzophenone, triethylamine and dichloromethane in a ratio of 0.05-0.2 mol: 0.1-0.3 mol: 100 mL.

7. The anti-cracking asphalt concrete material according to claim 1, characterized in that: The usage ratio of KH550, methanol and terminal double bond product in step B2 is 4.68-9.37 mL:10 mL:5.6-11.2 g.

8. The anti-cracking asphalt concrete material according to claim 1, characterized in that: In step B3, the usage ratio of tetraethyl orthosilicate, ethanol and solution A is 11-22 mL: 20 mL: 20 mL, and the usage ratio of grafted modified silane, KH550 and ethanol in solution A is 3-6 g: 1.5-2.5 mL: 20 mL.

9. A method for preparing the anti-cracking asphalt concrete material according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step S1, weighing raw materials by weight, mixing and stirring coarse aggregate, fine aggregate, fly ash and reinforcing filler to obtain a mixed dry material; Step S2: heating the asphalt to 140-170° C., stirring continuously, and sequentially adding the mixed dry materials and the composite aerogel, and mixing them evenly to obtain the anti-cracking asphalt concrete material.

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