Pavement crack sealant and preparation method thereof

Abstract

The invention belongs to the technical field of sealing materials, and particularly relates to a pavement crack sealant and a preparation method thereof. Petroleum asphalt is modified through coal tar and polyethylene glycol to obtain a petroleum asphalt composite material, the petroleum asphalt composite material is matched with calcium carbonate modified SBS rubber and aminated carbon nanotubes for common use, the pavement crack sealant is prepared, the softening point is effectively increased, the elastic recovery rate is increased, and good tensile strength is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of sealing materials, and particularly relates to a pavement crack sealant and a preparation method thereof. Background Art

[0002] Asphalt pavements are widely used in road engineering due to their advantages, including short construction period, low noise, safety, comfortable driving, recyclability, etc. With the rapid growth of traffic volume and vehicle load, serious asphalt pavement damage has occurred, and road maintenance measures have gradually become the key to ensuring service performance. Among many types of pavement damage, pavement cracking is one of the most common damage forms, which not only destroys the integrity of the pavement, but also causes water penetration, softens the base, weakens the bearing capacity of the base, and causes structural damage to the road. Asphalt sealant materials mainly consist of base asphalt, rubber powder, various polymers, softeners, fillers, etc., and the performance of asphalt sealants is improved by introducing different waste / raw polymers.

[0003] Chinese Patent (publication number: CN107245321B) discloses a pavement crack sealant and a preparation method thereof. The invention uses waste tire pyrolysis oil and LDPE plastic particles to produce a high-performance pavement crack sealant. The pavement crack sealant has excellent high and low temperature performance, good viscoelasticity and crack resistance, and good durability. It has the advantages of long storage time and good workability during construction, and can be used all-weather, and is suitable for repairing various types of road surfaces in any weather and environment. However, in the current technology, the pavement crack sealant still has problems such as low softening point, poor elastic recovery rate, and small tensile strength, which seriously affect its actual use.

[0004] Therefore, how to modify the main components of the sealant, introduce functional components, prepare a pavement crack sealant, effectively improve the softening point, increase the elastic recovery rate, and obtain good tensile strength has become the key direction to be focused on. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a pavement crack sealant and a preparation method thereof, aiming to solve the problems of low softening point, poor elastic recovery rate, and small tensile strength existing in the pavement crack sealant in the prior art.

[0006] The present invention modifies petroleum asphalt through coal tar and polyethylene glycol to obtain a petroleum asphalt composite material, and cooperates with the common use of calcium carbonate modified SBS rubber and amino-functionalized carbon nanotubes to prepare a pavement crack sealant, effectively improving the softening point, increasing the elastic recovery rate, and obtaining good tensile strength.

[0007] The technical solutions adopted by the present invention to solve the above technical problems are as follows:

[0008] In the first aspect of the present invention, a pavement crack sealant is provided.

[0009] By weight, it includes the following components: 55 - 65 parts of petroleum asphalt composite, 14 - 18 parts of SBS rubber, 10 - 12 parts of carbon nanotubes, 8 - 10 parts of mineral oil, 4 - 6 parts of acrylate, and 0.8 - 1.2 parts of plasticizer.

[0010] The preparation method of the petroleum asphalt composite includes: by weight, mixing 10 - 20 parts of coal tar and 0.4 - 0.8 parts of polyethylene glycol for stirring treatment to obtain modified coal tar; heating 100 - 120 parts of petroleum asphalt to a molten state, and then adding 10 - 20 parts of the modified coal tar and shearing and stirring evenly to obtain the petroleum asphalt composite.

[0011] The coal tar in the petroleum asphalt composite contains a large amount of high - molecular - weight aromatic compounds, which have a relatively high glass transition temperature and thermal stability. At the same time, the flexible chain segments of polyethylene glycol can restrict the free movement of coal tar and petroleum asphalt molecules, effectively delaying the softening process and increasing the softening point of the sealant.

[0012] As a preferred technical solution of the present invention, the conditions of the stirring treatment include: first, mechanically stirring at 70 - 74 °C for 10 - 20 min, then using a high - speed shearer to stir and shear at a rotation speed of 800 - 1000 r / min for 60 - 80 min, and cooling and standing for 4 - 6 h.

[0013] As a preferred technical solution of the present invention, the SBS rubber is calcium carbonate - modified SBS rubber.

[0014] The preparation method of the calcium carbonate - modified SBS rubber includes: by weight, pretreating 10 - 20 parts of calcium carbonate, and then mixing it with 1 - 3 parts of γ - glycidoxypropyltrimethoxysilane, 20 - 30 parts of deionized water, 20 - 30 parts of absolute ethanol, and 340 - 360 parts of ethyl acetate for heating reflux treatment to obtain epoxidized calcium carbonate; adding 100 - 120 parts of commercially available SBS rubber, 1 - 3 parts of stearic acid, and 10 - 20 parts of the epoxidized calcium carbonate into a Haake torque rheometer for kneading treatment to obtain the calcium carbonate - modified SBS rubber.

[0015] As a preferred technical solution of the present invention, the conditions of the heating reflux treatment include: heating reflux at 70 - 80 °C for 160 - 180 min, washing with absolute ethanol, filtering, and vacuum - drying at 50 - 60 °C for 60 - 70 h.

[0016] As a preferred technical solution of the present invention, the conditions for the pretreatment include: drying at 140-150 °C for 100-120 min.

[0017] As a preferred technical solution of the present invention, the conditions for the kneading treatment include: the kneading temperature is 140-150 °C, and the kneading time is 8-12 min.

[0018] The calcium carbonate modified SBS rubber surface-modifies calcium carbonate through a silane coupling agent, significantly improving its interfacial bonding with the SBS rubber. The good interfacial bonding enhances the interaction between the filler and the matrix, improving the overall mechanical properties of the material. At the same time, the presence of the epoxidized calcium carbonate particles will hinder the movement of the SBS rubber molecular chains, promoting the rapid recovery of the molecular chains after the external force is unloaded, thereby improving the elastic recovery rate of the sealant.

[0019] As a preferred technical solution of the present invention, the carbon nanotubes are amino-functionalized carbon nanotubes;

[0020] The preparation method of the amino-functionalized carbon nanotubes includes: by weight, acidifying 2-4 parts of commercially available carbon nanotubes, then adding them to 20-30 parts of N,N-dimethylformamide and mixing evenly, and then adding 40-50 parts of a 1,3,5-benzenetricarboxylic acid ethanol solution with a mass concentration of 2-4% and 40-50 parts of a copper nitrate trihydrate aqueous solution with a mass concentration of 5-7% and ultrasonically mixing, drying to obtain modified carbon nanotubes; fully dissolving 1-3 parts of branched polyethyleneimine in 200-240 parts of deionized water, and then adding 2-4 parts of the modified carbon nanotubes for an amination reaction to obtain amino-functionalized carbon nanotubes.

[0021] As a preferred technical solution of the present invention, the conditions for the acidification treatment include: mixing 2-4 parts of commercially available carbon nanotubes, 40-50 parts of nitric acid and 40-50 parts of sulfuric acid, stirring at 80-90 °C for 2-4 h, washing with water, and drying.

[0022] As a preferred technical solution of the present invention, the conditions for the amination reaction include: first ultrasonically treating for 120-140 min, then stirring at 60-70 °C for 2-4 h, and vacuum drying.

[0023] As a preferred technical solution of the present invention, the length of the commercially available carbon nanotubes is 5-10 μm.

[0024] The amino-functionalized carbon nanotubes form a metal-organic framework through 1,3,5-benzenetricarboxylic acid and copper nitrate trihydrate. It has a high specific surface area and pore structure, can adsorb molecules in the sealant matrix to form physical cross-linking points, and improve the overall mechanical properties. At the same time, the porous structure of the metal-organic framework also helps the uniform distribution of the amino-functionalized carbon nanotubes in the matrix, reduces stress concentration points, and improves the tensile strength of the sealant.

[0025] As a preferred technical solution of the present invention, the plasticizer is dibutyl phthalate and chlorinated paraffin.

[0026] As a preferred technical solution of the present invention, the mass ratio of dibutyl phthalate to chlorinated paraffin is (1-2):1.

[0027] In the second aspect of the present invention, there is provided a preparation method of the pavement crack sealant as described in the first aspect,

[0028] including the following steps:

[0029] By weight, 55-65 parts of the petroleum asphalt composite material are stirred at 150-160 °C for 2-4 h, then 8-10 parts of mineral oil and 4-6 parts of acrylate are added and dispersed evenly, and then 14-18 parts of SBS rubber, 10-12 parts of carbon nanotubes and 0.8-1.2 parts of plasticizer are added and stirred evenly, and sheared at 180-190 °C for 20-30 min, and cooled to room temperature to obtain the pavement crack sealant.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The polyethylene glycol in the petroleum asphalt composite material of the present invention has a large number of hydroxyl groups, which can promote the ring-opening reaction of the epoxy group (introduced by the coupling agent in the calcium carbonate-modified SBS rubber) to form stable covalent bonds. At the same time, the carboxyl group contained in the coal tar in the petroleum asphalt composite material can react with the amino group of the amino-functionalized carbon nanotubes through dehydration condensation reaction to form amide bonds, and the benzene ring structure of the aromatic compounds in the coal tar can have a π-π conjugation effect with the surface of the carbon nanotubes, thereby forming a dense network structure. The dense network structure introduces rigid materials such as carbon nanotubes to restrict the movement of molecular chains, thereby increasing the softening point, enabling the material to recover to its original state faster after deformation and improving the elastic recovery rate. At the same time, it can also reduce local stress concentration to enhance the tensile strength.

[0032] (2) The coal tar in the petroleum asphalt composite material of the present invention contains a large number of high-molecular-weight aromatic compounds, which have relatively high glass transition temperatures and thermal stabilities. At the same time, the flexible chain segments of polyethylene glycol can restrict the free movement of coal tar and petroleum asphalt molecules, effectively delaying the softening process, thereby increasing the softening point of the sealant.

[0033] (3) The calcium carbonate modified SBS rubber of the present invention performs surface modification on calcium carbonate through a silane coupling agent, significantly improving its interfacial bonding with SBS rubber. The good interfacial bonding enhances the interaction between the filler and the matrix, improving the overall mechanical properties of the material. At the same time, the presence of epoxidized calcium carbonate particles will hinder the movement of SBS rubber molecular chains, promoting the rapid recovery of molecular chains after unloading the external force, thereby improving the elastic recovery rate of the sealant.

[0034] (4) The amino-functionalized carbon nanotubes of the present invention form a metal-organic framework through 1,3,5-benzenetricarboxylic acid and copper nitrate trihydrate. It has a high specific surface area and pore structure, can adsorb molecules in the sealant matrix, form physical cross-linking points, and enhance the overall mechanical properties. At the same time, the porous structure of the metal-organic framework also helps the uniform distribution of amino-functionalized carbon nanotubes in the matrix, reducing stress concentration points and improving the tensile strength of the sealant. Specific Embodiments

[0035] To facilitate the understanding of the present invention, the following examples are listed. Those skilled in the art should understand that the examples are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0036] The sources of some components in the examples and comparative examples are as follows:

[0037] Commercially available petroleum asphalt, product number WA89415, purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.;

[0038] Commercially available SBS rubber, grade YH-796E, purchased from Sinopec Baling Petrochemical Company;

[0039] Commercially available carbon nanotubes I, product number C121262, with a length of 10 μm, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0040] Commercially available carbon nanotubes II, product number C121257, with a length of 20 μm, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0041] Commercially available carbon nanotubes III, product number C369044, with a length of 1 μm, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0042] Mineral oil, CAS number 8020-83-5, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0043] Acrylate, product number P164166, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0044] Dibutyl phthalate, CAS number 84-74-2, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0045] Chlorinated paraffin, CAS No. 63449-39-8, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0046] Coal tar, CAS No. 8007-45-2, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0047] Polyethylene glycol, product number P103724, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0048] Calcium carbonate, CAS No. 471-34-1, was purchased from Shanghai Macklin Biochemical Co., Ltd.;

[0049] γ-Glycidoxypropyltrimethoxysilane, CAS No. 2530-83-8, was purchased from Shanghai Macklin Biochemical Co., Ltd.;

[0050] Absolute ethanol, CAS No. 64-17-5, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0051] Ethyl acetate, CAS No. 141-78-6, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0052] Stearic acid, CAS No. 57-11-4, was purchased from Shanghai Macklin Biochemical Co., Ltd.;

[0053] Nitric acid, CAS No. 7697-37-2, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0054] Sulfuric acid, CAS No. 7664-93-9, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0055] N,N-Dimethylformamide, CAS No. 68-12-2, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0056] 1,3,5-Benzenetricarboxylic acid, CAS No. 554-95-0, was purchased from Shanghai Macklin Biochemical Co., Ltd.;

[0057] Branched polyethyleneimine, product number P434400, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Example 1

[0058] This example provides a pavement crack sealant, which, by weight, comprises the following components:

[0059] 65 parts of petroleum asphalt composite, 18 parts of calcium carbonate modified SBS rubber, 12 parts of amino-functionalized carbon nanotubes, 10 parts of mineral oil, 6 parts of acrylate, and 1.2 parts of plasticizer (0.8 part of dibutyl phthalate and 0.4 part of chlorinated paraffin);

[0060] Preparation of the petroleum asphalt composite material: By weight, 20 parts of coal tar and 0.8 part of polyethylene glycol are mixed and subjected to stirring treatment. First, mechanical stirring is carried out at 74 °C for 10 min, and then stirring and shearing are carried out with a high-speed shearer at a rotation speed of 1000 r / min for 60 min. After cooling and standing for 6 h, modified coal tar is obtained; 120 parts of petroleum asphalt are heated to a molten state, and then 20 parts of the modified coal tar are added and sheared and stirred evenly to obtain the petroleum asphalt composite material.

[0061] Preparation of the calcium carbonate modified SBS rubber: By weight, 20 parts of calcium carbonate are pretreated (dried at 150 °C for 100 min), and then mixed with 3 parts of γ-glycidoxypropyltrimethoxysilane, 30 parts of deionized water, 30 parts of absolute ethanol and 360 parts of ethyl acetate for heating reflux treatment. Heating reflux is carried out at 80 °C for 160 min, washed with absolute ethanol, filtered, and vacuum dried at 60 °C for 60 h to obtain epoxidized calcium carbonate; 120 parts of commercially available SBS rubber, 3 parts of stearic acid and 20 parts of the epoxidized calcium carbonate are added to a Haake torque rheometer for internal mixing treatment (temperature is 150 °C, time is 8 min) to obtain the calcium carbonate modified SBS rubber.

[0062] Preparation of the amino-functionalized carbon nanotubes: By weight, 4 parts of commercially available carbon nanotubes I (product number C121262, length is 10 μm), 50 parts of nitric acid and 50 parts of sulfuric acid are mixed, stirred at 90 °C for 2 h, washed with water and dried, and then added to 30 parts of N,N-dimethylformamide and mixed evenly. Then 50 parts of a 2% by mass concentration ethanol solution of 1,3,5-benzenetricarboxylic acid and 50 parts of a 5% by mass concentration aqueous solution of copper nitrate trihydrate are added and ultrasonically mixed, and dried to obtain modified carbon nanotubes; 3 parts of branched polyethyleneimine are fully dissolved in 240 parts of deionized water, and then 4 parts of the modified carbon nanotubes are added for amino-functionalization reaction. First, ultrasonic treatment is carried out for 140 min, and then stirring is carried out at 70 °C for 2 h, and vacuum drying is carried out to obtain the amino-functionalized carbon nanotubes.

[0063] Example 2

[0064] This example provides a pavement crack sealant, which includes the following components by weight:

[0065] 55 parts of petroleum asphalt composite material, 14 parts of calcium carbonate modified SBS rubber, 10 parts of amino-functionalized carbon nanotubes, 8 parts of mineral oil, 4 parts of acrylate and 0.8 part of plasticizer (0.4 part of dibutyl phthalate and 0.4 part of chlorinated paraffin);

[0066] Preparation of the petroleum asphalt composite material: By weight, 10 parts of coal tar and 0.4 part of polyethylene glycol are mixed and subjected to stirring treatment. First, mechanical stirring is carried out at 70 °C for 20 min, then stirring and shearing are carried out with a high-speed shearer at a rotation speed of 800 r / min for 80 min, and then it is cooled and allowed to stand for 4 h to obtain modified coal tar; 100 parts of petroleum asphalt are heated to a molten state, and then 10 parts of the modified coal tar are added and sheared and stirred evenly to obtain the petroleum asphalt composite material.

[0067] Preparation of the calcium carbonate modified SBS rubber: By weight, 10 parts of calcium carbonate are pretreated (dried at 140 °C for 120 min), and then mixed with 1 part of γ-glycidoxypropyltrimethoxysilane, 20 parts of deionized water, 20 parts of absolute ethanol and 340 parts of ethyl acetate for heat reflux treatment. Heat reflux is carried out at 70 °C for 180 min, washed with absolute ethanol, filtered, and vacuum dried at 50 °C for 70 h to obtain epoxidized calcium carbonate; 100 parts of commercially available SBS rubber, 1 part of stearic acid and 10 parts of the epoxidized calcium carbonate are added to a Haake torque rheometer for internal mixing treatment (temperature is 140 °C, time is 12 min) to obtain the calcium carbonate modified SBS rubber.

[0068] Preparation of the amino-functionalized carbon nanotubes: By weight, 2 parts of commercially available carbon nanotubes I (product number C121262, length is 10 μm), 40 parts of nitric acid and 40 parts of sulfuric acid are mixed, stirred at 80 °C for 4 h, washed with water and dried, and then added to 20 parts of N,N-dimethylformamide and mixed evenly. Then 40 parts of a 4% by mass concentration ethanol solution of 1,3,5-benzenetricarboxylic acid and 40 parts of a 7% by mass concentration aqueous solution of copper nitrate trihydrate are added and ultrasonically mixed, and then dried to obtain modified carbon nanotubes; 1 part of branched polyethyleneimine is fully dissolved in 200 parts of deionized water, and then 2 parts of the modified carbon nanotubes are added for amino-functionalization reaction. First, ultrasonic treatment is carried out for 120 min, then stirring is carried out at 60 °C for 4 h, and vacuum drying is carried out to obtain the amino-functionalized carbon nanotubes.

[0069] Example 3

[0070] This example provides a pavement crack sealant, which includes the following components by weight:

[0071] 60 parts of petroleum asphalt composite material, 16 parts of calcium carbonate modified SBS rubber, 11 parts of amino-functionalized carbon nanotubes, 9 parts of mineral oil, 5 parts of acrylate and 1.0 part of plasticizer (0.6 part of dibutyl phthalate and 0.4 part of chlorinated paraffin);

[0072] Preparation of the petroleum asphalt composite material: By weight, 15 parts of coal tar and 0.6 part of polyethylene glycol are mixed and stirred. First, mechanically stir at 72 °C for 15 min, then use a high-speed shear machine to stir and shear at a rotation speed of 900 r / min for 70 min, cool and stand for 5 h to obtain modified coal tar; heat 110 parts of petroleum asphalt to the molten state, then add 15 parts of the modified coal tar and shear and stir evenly to obtain the petroleum asphalt composite material.

[0073] Preparation of the calcium carbonate modified SBS rubber: By weight, 15 parts of calcium carbonate are pretreated (dried at 145 °C for 110 min), then mixed with 2 parts of γ-glycidoxypropyltrimethoxysilane, 25 parts of deionized water, 25 parts of absolute ethanol and 350 parts of ethyl acetate and subjected to heat reflux treatment. Heat reflux at 75 °C for 170 min, wash with absolute ethanol, filter, and vacuum dry at 55 °C for 65 h to obtain epoxidized calcium carbonate; add 110 parts of commercially available SBS rubber, 2 parts of stearic acid and 15 parts of the epoxidized calcium carbonate into a Haake torque rheometer for internal mixing treatment (temperature is 145 °C, time is 10 min) to obtain the calcium carbonate modified SBS rubber.

[0074] Preparation of the amino-functionalized carbon nanotubes: By weight, 3 parts of commercially available carbon nanotubes I (product number C121262, length is 10 μm), 45 parts of nitric acid and 45 parts of sulfuric acid are mixed, stirred at 85 °C for 3 h, washed with water and dried, then added to 25 parts of N,N-dimethylformamide and mixed evenly, and then added with 45 parts of a 3% by mass concentration 1,3,5-benzenetricarboxylic acid ethanol solution and 45 parts of a 6% by mass concentration copper nitrate trihydrate aqueous solution and ultrasonically mixed, and dried to obtain modified carbon nanotubes; fully dissolve 2 parts of branched polyethyleneimine in 220 parts of deionized water, then add 3 parts of the modified carbon nanotubes for amino-functionalization reaction. First, ultrasonically treat for 130 min, then stir at 65 °C for 3 h, and vacuum dry to obtain the amino-functionalized carbon nanotubes.

[0075] Comparative Example 1

[0076] The difference between this comparative example and Example 1 is that commercially available petroleum asphalt (product number WA89415) is used to replace the petroleum asphalt composite material.

[0077] Comparative Example 2

[0078] The difference between this comparative example and Example 1 is that commercially available carbon nanotubes I (product number C121262) are used to replace the amino-functionalized carbon nanotubes.

[0079] Comparative Example 3

[0080] The difference between this comparative example and Example 1 is that commercially available carbon nanotubes II (product number C121257) are used to replace commercially available carbon nanotubes I for the preparation of amino-functionalized carbon nanotubes.

[0081] Comparative Example 4

[0082] The difference between this comparative example and Example 1 is that commercially available carbon nanotubes III (product number C369044) are used to replace commercially available carbon nanotubes I for the preparation of amino-functionalized carbon nanotubes.

[0083] Comparative Example 5

[0084] The difference between this comparative example and Example 1 is that commercially available SBS rubber (grade YH-796E) is used to replace calcium carbonate modified SBS rubber.

[0085] Comparative Example 6

[0086] The difference between this comparative example and Example 1 is that the dosage of dibutyl phthalate in the plasticizer is changed to 1.0 part, and the dosage of chlorinated paraffin is changed to 0.2 part.

[0087] Comparative Example 7

[0088] The difference between this comparative example and Example 1 is that the dosage of dibutyl phthalate in the plasticizer is changed to 0.4 part, and the dosage of chlorinated paraffin is changed to 0.8 part.

[0089] The performance of the pavement crack sealants provided in the above examples and comparative examples was tested, and the test methods are as follows:

[0090] (1) Softening point test after thermal aging: The test was carried out according to the requirements of "JT / T 740-2024 Pavement Heating Type Crack Sealing Adhesive".

[0091] (2) Elastic recovery rate test: The test was carried out according to the requirements of "JT / T 203-2014 Highway Cement Concrete Pavement Joint Materials".

[0092] (3) Tensile strength test: The test was carried out according to the requirements of "JT / T 203-2014 Highway Cement Concrete Pavement Joint Materials".

[0093] The above performance test data are shown in Table 1.

[0094] Table 1 Performance Test Results

[0095] Softening point after thermal aging (°C) Elastic recovery rate (%) Tensile strength (MPa) Example 1 98.1 91.8 0.99 Example 2 97.5 91.1 0.96 Example 3 97.8 91.4 0.98 Comparative Example 1 84.6 65.1 0.58 Comparative Example 2 85.3 66.4 0.62 Comparative Example 3 91.6 77.8 0.74 Comparative Example 4 92.4 79.2 0.79 Comparative Example 5 85.1 65.8 0.59 Comparative Example 6 92.1 78.5 0.76 Comparative Example 7 92.7 79.9 0.81

[0096] As can be seen from the above, in the present invention, petroleum asphalt composite material is obtained by modifying petroleum asphalt with coal tar and polyethylene glycol. In combination with the co - use of calcium carbonate - modified SBS rubber and amino - functionalized carbon nanotubes, a pavement crack sealant is prepared (Examples 1 - 3), which has better comprehensive performance, with a softening point of 97.5 - 98.1 °C, an elastic recovery rate of 91.1 - 91.8%, and a tensile strength of 0.96 - 0.99 MPa.

[0097] Compared with Example 1, when using commercially available petroleum asphalt (product number WA89415) to replace the petroleum asphalt composite material, the softening point decreases, the elastic recovery rate deteriorates, and the tensile strength decreases (Comparative Example 1); compared with Example 1, when using commercially available carbon nanotube Ⅰ to replace the amino - functionalized carbon nanotubes, the softening point decreases, the elastic recovery rate deteriorates, and the tensile strength decreases (Comparative Example 2); compared with Example 1, when using commercially available carbon nanotube Ⅱ to prepare amino - functionalized carbon nanotubes instead of commercially available carbon nanotube Ⅰ, due to the excessive length of commercially available carbon nanotube Ⅱ, the modification effect is poor, so the softening point decreases, the elastic recovery rate deteriorates, and the tensile strength decreases (Comparative Example 3); compared with Example 1, when using commercially available carbon nanotube Ⅲ to prepare amino - functionalized carbon nanotubes instead of commercially available carbon nanotube Ⅰ, due to the too short length of commercially available carbon nanotube Ⅲ, the modification effect is poor, so the softening point decreases, the elastic recovery rate deteriorates, and the tensile strength decreases (Comparative Example 4); compared with Example 1, when using commercially available SBS rubber (grade YH - 796E) to replace the calcium carbonate - modified SBS rubber, the softening point decreases, the elastic recovery rate deteriorates, and the tensile strength decreases (Comparative Example 5); compared with Example 1, when the dosage of dibutyl phthalate in the plasticizer is changed to 1.0 part and the dosage of chlorinated paraffin is changed to 0.2 part, due to the excessive dosage of dibutyl phthalate, the compounding effect is poor, so the softening point decreases, the elastic recovery rate deteriorates, and the tensile strength decreases (Comparative Example 6); compared with Example 1, when the dosage of dibutyl phthalate in the plasticizer is changed to 0.4 part and the dosage of chlorinated paraffin is changed to 0.8 part, due to the too small dosage of dibutyl phthalate, the compounding effect is poor, so the softening point decreases, the elastic recovery rate deteriorates, and the tensile strength decreases (Comparative Example 7).

[0098] In summary, in the present invention, petroleum asphalt composite material is obtained by modifying petroleum asphalt with coal tar and polyethylene glycol. In combination with the co - use of calcium carbonate - modified SBS rubber and amino - functionalized carbon nanotubes, a pavement crack sealant is prepared, effectively improving the softening point, increasing the elastic recovery rate, and obtaining good tensile strength.

Claims

1. A pavement crack sealant, characterized in that: The composition comprises the following components in parts by weight: 55 to 65 parts of petroleum asphalt composite material, 14 to 18 parts of SBS rubber, 10 to 12 parts of carbon nanotubes, 8 to 10 parts of mineral oil, 4 to 6 parts of acrylate and 0.8 to 1.2 parts of plasticizer; The preparation method of the petroleum asphalt composite material comprises: mixing 10 to 20 parts of coal tar and 0.4 to 0.8 parts of polyethylene glycol by weight and stirring them to obtain modified coal tar; heating 100 to 120 parts of petroleum asphalt to a molten state, and then adding 10 to 20 parts of the modified coal tar and shearing and stirring them to obtain the petroleum asphalt composite material.

2. A road crack sealant according to claim 1, characterized in that: The stirring treatment conditions include: first mechanically stirring at 70-74° C. for 10-20 min, then stirring and shearing with a high-speed shearing machine at a speed of 800-1000 r / min for 60-80 min, and cooling and standing for 4-6 h.

3. A road crack sealant according to claim 1, characterized in that: The SBS rubber is calcium carbonate modified SBS rubber; The preparation method of the calcium carbonate modified SBS rubber comprises: pre-treating 10 to 20 parts of calcium carbonate by weight, and then mixing with 1 to 3 parts of γ-glycidyloxypropyltrimethoxysilane, 20 to 30 parts of deionized water, 20 to 30 parts of anhydrous ethanol and 340 to 360 parts of ethyl acetate for heating and reflux treatment to obtain epoxidized calcium carbonate; adding 100 to 120 parts of commercially available SBS rubber, 1 to 3 parts of stearic acid and 10 to 20 parts of the epoxidized calcium carbonate into a Haake torque rheometer for internal kneading treatment to obtain the calcium carbonate modified SBS rubber.

4. A road crack sealant according to claim 3, characterized in that: The conditions for the heating reflux treatment include: heating reflux at 70-80° C. for 160-180 min, washing with anhydrous ethanol, filtering, and vacuum drying at 50-60° C. for 60-70 h.

5. A road crack sealant according to claim 1, characterized in that: The carbon nanotubes are amino-modified carbon nanotubes; The preparation method of the amino carbon nanotubes comprises: acidifying 2 to 4 parts of commercially available carbon nanotubes by weight, then adding them into 20 to 30 parts of N,N-dimethylformamide and mixing them evenly, then adding 40 to 50 parts of 1,3,5-benzenetricarboxylic acid ethanol solution with a mass concentration of 2 to 4% and 40 to 50 parts of copper nitrate trihydrate aqueous solution with a mass concentration of 5 to 7%, ultrasonically mixing them, and drying them to obtain modified carbon nanotubes; and fully dissolving 1 to 3 parts of branched polyethyleneimine in 200 to 240 parts of deionized water, then adding 2 to 4 parts of the modified carbon nanotubes for amination reaction to obtain amino carbon nanotubes.

6. A road crack sealant according to claim 5, characterized in that: The acidification treatment conditions include: mixing 2-4 parts of commercially available carbon nanotubes, 40-50 parts of nitric acid and 40-50 parts of sulfuric acid, stirring at 80-90° C. for 2-4 hours, washing with water, and drying.

7. A road crack sealant according to claim 5, characterized in that: The conditions of the amination reaction include: firstly ultrasonic treatment for 120 to 140 minutes, then stirring at 60 to 70° C. for 2 to 4 hours, and vacuum drying.

8. A road crack sealant according to claim 5, characterized in that: The commercially available carbon nanotubes have a length of 5 to 10 μm.

9. A road crack sealant according to claim 1, characterized in that: The plasticizers are dibutyl phthalate and chlorinated paraffin; the mass ratio of dibutyl phthalate to chlorinated paraffin is (1-2):

1.

10. A method for preparing a road crack sealant according to any one of claims 1 to 9, characterized in that: The steps include: In parts by weight, 55 to 65 parts of petroleum asphalt composite material are stirred at 150 to 160° C. for 2 to 4 hours, then 8 to 10 parts of mineral oil and 4 to 6 parts of acrylate are added and dispersed evenly, then 14 to 18 parts of SBS rubber, 10 to 12 parts of carbon nanotubes and 0.8 to 1.2 parts of plasticizer are added and stirred evenly, and the mixture is sheared at 180 to 190° C. for 20 to 30 minutes and cooled to room temperature to obtain a pavement crack sealant.