High-toughness active cooling asphalt mortar and preparation method thereof

Abstract

The invention provides high-toughness active cooling asphalt mortar and a preparation method thereof, and the asphalt mortar is prepared from the following raw materials in parts by weight: 70 to 85 parts of matrix asphalt, 37.5 to 45 parts of mineral powder, 0.2 to 0.5 part of ceramic fiber and 30 to 45 parts of montmorillonite-SAP composite material. The montmorillonite-SAP composite material is formed by polymerizing organically modified sodium montmorillonite and acrylic monomers under the action of an initiator and a cross-linking agent, and has good heat absorption cooling and water storage slow release performance; the ceramic fibers can be uniformly dispersed in the mucilage after being lubricated, so that the crack resistance and the structural toughness of the ceramic fibers are improved; the mineral powder as an inorganic filler enhances the stability of the mucilage. The asphalt mortar provided by the invention not only can effectively reduce the temperature of an asphalt pavement and effectively reduce ruts and other diseases caused by high temperature of the pavement in summer, but also can remarkably improve the self toughness, thereby improving the anti-fatigue performance of the asphalt pavement structure.

Description

Technical Field

[0001] The invention belongs to the technical field of asphalt pavement materials, and particularly relates to a high-toughness active cooling asphalt mortar and a preparation method thereof. Background Art

[0002] Asphalt pavements are widely used on my country's high-grade highways and urban roads due to their ease of construction, excellent road performance, and high driving comfort. However, asphalt is a typically heat-sensitive material, and its thermophysical properties directly impact the stability and service life of the pavement structure. In particular, under high temperatures, asphalt binders are susceptible to softening due to heat absorption, resulting in a sharp drop in viscosity, which in turn reduces their bond with the aggregate. This causes the asphalt mixture to flow and deform under load, inducing a series of high-temperature defects such as rutting, lumping, and pushing. These conditions not only weaken the pavement's structural integrity but also significantly shorten its service life. Furthermore, the high heat absorption properties of asphalt pavements make them a "heating agent" for the urban heat island effect under summer sunlight, exacerbating abnormally high temperatures in urban areas, impacting resident health and the urban ecological environment. Of particular concern is that as temperatures rise, the release rate of pollutants such as volatile organic compounds (VOCs) and nitrogen oxides (NOx) contained in asphalt accelerates significantly, potentially polluting the atmospheric environment and exacerbating the deterioration of urban air quality.

[0003] To address these issues, researchers have proposed various strategies for cooling asphalt pavements, such as incorporating inorganic thermally conductive powders, phase change materials (PCMs), infrared reflective materials, and photocatalytic coatings to achieve passive or semi-active temperature regulation. However, these additives often have poor physical compatibility with the asphalt itself. While significantly improving cooling performance, they also reduce the ductility and toughness of the binder, resulting in decreased low-temperature crack resistance and weakened shear and compressive strength. This, in turn, impacts the overall durability and engineering adaptability of asphalt pavements, restricting their large-scale application. Therefore, there is an urgent need for a functional asphalt material that enhances asphalt's cooling capacity while also possessing excellent mechanical properties and temperature adaptability. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the deficiencies of the above-mentioned existing technologies and provide a high-toughness active cooling asphalt mortar and a preparation method thereof. The preparation process is simple, and it can reduce the road surface temperature and alleviate the impact of road rutting diseases. At the same time, it is supplemented by high-performance ceramic fiber as a reinforcing material to improve the toughness and crack resistance of the road surface structure.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a high-toughness active cooling asphalt mortar, which includes the following raw materials in parts by weight: 70 to 85 parts of matrix asphalt, 37.5 to 45 parts of mineral powder, 0.2 to 0.5 parts of ceramic fiber, and 30 to 45 parts of montmorillonite-SAP composite material.

[0006] Preferably, the matrix asphalt is AH-70 or AH-90; the length of the ceramic fiber is 3 to 10 mm; the mineral powder is limestone powder or silicate mineral powder, and its particle size distribution satisfies: the mass percentage passing through a 0.075 mm sieve is ≥85%, and the specific surface area is 350 to 550 m 2 / kg.

[0007] Preferably, the preparation method of the montmorillonite-SAP composite material is:

[0008] The organic matrix is ​​prepared into a solution with deionized water, the pH is adjusted to 7, and then the modified montmorillonite is added, and the mixture is stirred at 200-400 rpm for 15-30 minutes, and then placed in a water bath at 50-60°C for 15-20 minutes to obtain a mixed solution; an initiator is added to the mixed solution, and the mixture is stirred at 200-400 rpm for 10-15 minutes to promote a free radical polymerization reaction; the water bath temperature is increased to 70-80°C, and the stirring is continued for 15-20 minutes, and a cross-linking agent is added dropwise to react to form a stable montmorillonite-SAP composite gel-like material, and then placed in an ice water bath at 0°C for 6-8 hours to promote the stabilization of the polymer chain material; the mixture is washed with deionized water 5-7 times to remove unreacted substances, and then dried in a vacuum drying oven at 50-55°C for 4-6 hours, and ground into a 100-300 mesh powder to obtain a montmorillonite-SAP composite material;

[0009] The preparation method of the modified montmorillonite is:

[0010] Montmorillonite is added to deionized water and uniformly dispersed by ultrasonication to prepare a suspension; an organic modifier is then added dropwise to the suspension, and the mixture is stirred at 400-500 rpm for 1.2-1.5 hours. The resulting material, after centrifugation and washing, is vacuum-dried at 60-80° C. for 4-6 hours and ground into a 200-300 mesh powder to obtain the modified montmorillonite; wherein the montmorillonite is sodium montmorillonite, having a particle size of 100-300 μm and a specific surface area of ​​50-150 m2 / g; the organic modifier is one of dodecyltrimethylammonium bromide or hexadecyltrimethylammonium bromide, and the mass ratio of the montmorillonite to the organic modifier is (8-10):1;

[0011] Preferably, the organic matrix is ​​acrylic acid or acrylamide, the neutralizing solution used to adjust the pH is sodium hydroxide solution with a mass fraction of 30% to 45%; the initiator is potassium persulfate; and the cross-linking agent is N,N'-methylenebisacrylamide;

[0012] Preferably, the mass ratio of the organic matrix, modified montmorillonite, initiator and cross-linking agent is (23.4-31.2): (4.5-6.75): (0.6-0.9): (0.015-0.0225).

[0013] The present invention also provides a method for preparing the high-toughness active cooling asphalt mortar, comprising the following steps:

[0014] S1. Heat the base asphalt to 160-170°C and stir continuously at 500-700 rpm for 3-5 minutes to maintain uniform fluidity;

[0015] S2. Add mineral powder to the base asphalt treated in S1, and stir at a high speed of 1000-1200 rpm for 10-15 minutes to obtain mixture 1;

[0016] S3, adding the montmorillonite-SAP composite material to the mixture 1 obtained in S2, and continuing high-speed shear stirring at 1000-1200 rpm for 10-15 minutes to obtain a mixture 2;

[0017] S4. Uniformly coating the surface of the ceramic fiber with a lubricant, and then drying the ceramic fiber at 180° C. for 2 hours to remove the solvent and form a stable lubricating layer, thereby obtaining a ceramic fiber comprising a lubricating layer; the lubricant is a 3% by mass paraffin solution;

[0018] S5. Add the ceramic fiber containing the lubricating layer obtained in S4 to the mixture 2 obtained in S3, and shear and stir at 500-700 rpm for 10-15 minutes to prepare a high-toughness active cooling asphalt mortar.

[0019] Compared with the prior art, the present invention has the following significant technical effects:

[0020] 1. The present invention provides a high-toughness active cooling asphalt mortar and a preparation method thereof. The raw materials are base asphalt, mineral powder, ceramic fiber and montmorillonite-SAP composite material. The preparation process is simple. The obtained asphalt mortar can not only effectively reduce the temperature of the asphalt pavement and effectively reduce rutting and other diseases caused by high temperature of the pavement in summer, but also significantly improve its own toughness, thereby improving the fatigue resistance of the asphalt pavement structure.

[0021] 2. The montmorillonite-SAP composite material of the present invention is polymerized by organically modified sodium montmorillonite and acrylic monomers under the action of an initiator and a cross-linking agent, and has good heat absorption, cooling, water storage and slow-release properties; high-performance ceramic fiber is used as a reinforcing material and can be evenly dispersed in the mortar after lubrication treatment, thereby improving its crack resistance and structural toughness; mineral powder is used as an inorganic filler to enhance the stability of the mortar.

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The invention relates to a heating process of a rutting plate made of the asphalt mortar prepared by the invention;

[0024] Figure 2 The invention relates to a temperature measurement process of each layer of a rutting plate made of the asphalt mortar prepared by the invention. DETAILED DESCRIPTION

[0025] The specifications of raw materials used in the present invention are as follows:

[0026] The base asphalt is AH-70 or AH-90;

[0027] The length of ceramic fiber is 3 to 10 mm;

[0028] The mineral powder is limestone powder or silicate mineral powder, and its particle size distribution meets the following requirements: the mass percentage passing through a 0.075mm sieve is ≥85%, and the specific surface area is 350~550m 2 / kg;

[0029] Montmorillonite is sodium montmorillonite with a particle size of 100 to 300 μm and a specific surface area of ​​50 to 150 m 2 / g.

[0030] Example 1

[0031] This embodiment is a high-toughness active cooling asphalt mortar, which includes the following raw materials according to mass measurement: 85 parts of AH-70 matrix asphalt, 45 parts of mineral powder, 0.2 parts of ceramic fiber, and 30 parts of montmorillonite-SAP composite material.

[0032] The preparation method of the high-toughness active cooling asphalt mortar comprises the following steps:

[0033] S1. Heat 85 parts of base asphalt in an oven to 160°C and continuously stir magnetically at 700 rpm for 5 minutes to maintain uniform fluidity.

[0034] S2. Gradually add 45 parts of mineral powder to the base asphalt treated in S1, and perform high-speed shear stirring at 1000 rpm for 15 minutes to obtain mixture 1;

[0035] S3. Slowly add 30 parts of montmorillonite-SAP composite material to the mixture 1 obtained in S2, and continue high-speed shear stirring at 1000 rpm for 15 minutes to obtain mixture 2;

[0036] S4, uniformly coating 0.2 parts of the ceramic fiber surface with a 3% paraffin solution, and drying the coated ceramic fiber at 180° C. for 2 hours to remove the solvent and form a stable lubricating layer, thereby obtaining a ceramic fiber containing a lubricating layer;

[0037] S5. Add the ceramic fiber containing the lubricating layer obtained in S4 to the mixture 2 obtained in S3, and shear and stir at 700 rpm for 10 minutes to prepare a high-toughness active cooling asphalt mortar.

[0038] The preparation method of the montmorillonite-SAP composite material is as follows:

[0039] First, the modified montmorillonite was prepared as follows: (1) 9.0 parts of sodium montmorillonite was placed in a beaker containing deionized water to prepare a suspension, and ultrasonic treatment was performed at 40 kHz for 30 minutes to improve the dispersibility of the montmorillonite; (2) 1.0 parts of dodecyltrimethylammonium bromide was slowly added dropwise and stirred at 400 rpm for 1.5 hours; (3) the mixture was centrifuged and filtered, and then washed three times with deionized water to remove unreacted impurities; (4) the obtained material was dried in a vacuum drying oven at 60°C for 6 hours and ground into a powder of 200-300 mesh, which is the modified montmorillonite;

[0040] Then, montmorillonite-SAP composite material was prepared: (1) 23.4 parts of acrylic acid were added to a beaker, and a 25% by mass acrylic acid solution was prepared with deionized water, and a 35% by mass sodium hydroxide (NaOH) solution was slowly added dropwise to adjust the pH to 7; (2) 4.5 parts of the prepared modified montmorillonite were gradually added, and magnetic stirring was carried out at 400 rpm for 15 minutes, and then the mixture was placed in a 50°C water bath for 20 minutes; (3) 0.6 parts of potassium persulfate were added to the mixture, and magnetic stirring was carried out at 400 rpm for 10 minutes. n, to promote free radical polymerization reaction; (4) increase the water bath temperature to 80℃, continue stirring for 15 minutes, and at the same time, add 0.015 parts of N,N'-methylenebisacrylamide dropwise to react and form a stable montmorillonite-SAP composite gel material; (5) place the beaker in a 0℃ ice water bath and let it stand for 8 hours to promote the stabilization of the polymer chain material; (6) wash with deionized water 5 times to remove unreacted substances, and then dry in a vacuum drying oven at 50℃ for 6 hours; (7) after drying, grind to 100-300 mesh powder to obtain a montmorillonite-SAP composite material.

[0041] Example 2

[0042] This embodiment is a high-toughness active cooling asphalt mortar, which includes the following raw materials according to mass measurement: 80 parts of AH-70 matrix asphalt, 42.5 parts of mineral powder, 0.3 parts of ceramic fiber, and 35 parts of montmorillonite-SAP composite material.

[0043] The preparation method of the high-toughness active cooling asphalt mortar comprises the following steps:

[0044] S1. Heat 80 parts of base asphalt in an oven to 170°C and continuously stir magnetically at 500 rpm for 5 minutes to maintain uniform fluidity.

[0045] S2. Gradually add 42.5 parts of mineral powder to the base asphalt treated in S1, and perform high-speed shear stirring at 1000 rpm for 15 minutes to obtain mixture 1;

[0046] S3. Slowly add 35 parts of montmorillonite-SAP composite material to the mixture 1 obtained in S2, and continue high-speed shear stirring at 1000 rpm for 15 minutes to obtain mixture 2;

[0047] S4, uniformly coating a 3% paraffin solution on the surface of 0.3 parts of the ceramic fiber, and drying the coated ceramic fiber at 180° C. for 2 hours to remove the solvent and form a stable lubricating layer, thereby obtaining a ceramic fiber containing a lubricating layer;

[0048] S5. Add the ceramic fiber containing the lubricating layer obtained in S4 to the mixture 2 obtained in S3, and shear and stir at 500 rpm for 15 minutes to prepare a high-toughness active cooling asphalt mortar.

[0049] The preparation method of the montmorillonite-SAP composite material is as follows:

[0050] First, the modified montmorillonite was prepared as follows: (1) 8.0 parts of sodium montmorillonite was placed in a beaker containing deionized water to prepare a suspension, and ultrasonic treatment was performed at 40 kHz for 30 minutes to improve the dispersibility of the montmorillonite; (2) 1.0 part of dodecyltrimethylammonium bromide was slowly added dropwise and stirred at 500 rpm for 1.2 hours; (3) the suspension was centrifuged and filtered, and then washed twice with deionized water to remove unreacted impurities; (4) the obtained material was dried in a vacuum drying oven at 80°C for 4 hours and ground into a 200-300 mesh powder, which is the modified montmorillonite;

[0051] Then, montmorillonite-SAP composite material was prepared: (1) 27.3 parts of acrylic acid was added to a beaker, and a 25% by mass acrylic acid solution was prepared with deionized water, and a 40% by mass sodium hydroxide (NaOH) solution was slowly added dropwise to adjust the pH to 7; (2) 6.6 parts of the prepared modified montmorillonite was gradually added, and magnetic stirring was carried out at 200 rpm for 30 minutes, and then the mixture was placed in a water bath at 60°C for 15 minutes; (3) 0.74 parts of potassium persulfate was added to the mixture, and magnetic stirring was carried out at 400 rpm for 15 minutes. in to promote free radical polymerization reaction; (4) increase the water bath temperature to 70℃, continue stirring for 20 minutes, and at the same time, add 0.022 parts of N,N'-methylenebisacrylamide dropwise to react and form a stable montmorillonite-SAP composite gel material; (5) place the beaker in a 0℃ ice water bath and let it stand for 6 hours to promote the stabilization of the polymer chain material; (6) wash with deionized water 7 times to remove unreacted substances, and then dry in a vacuum drying oven at 55℃ for 4 hours; (7) grind to 100-300 mesh powder after drying to obtain a montmorillonite-SAP composite material.

[0052] Example 3

[0053] This embodiment is a high-toughness active cooling asphalt mortar, which includes the following raw materials according to mass measurement: 75 parts of AH-70 matrix asphalt, 40 parts of mineral powder, 0.4 parts of ceramic fiber, and 40 parts of montmorillonite-SAP composite material.

[0054] The preparation method of the high-toughness active cooling asphalt mortar comprises the following steps:

[0055] S1. Heat 75 parts of base asphalt in an oven to 165°C and continuously stir magnetically at 600 rpm for 3 minutes to maintain uniform fluidity.

[0056] S2. Gradually add 40 parts of mineral powder to the base asphalt treated in S1, and perform high-speed shear stirring at 1200 rpm for 10 minutes to obtain mixture 1;

[0057] S3. Slowly add 40 parts of montmorillonite-SAP composite material to the mixture 1 obtained in S2, and continue high-speed shear stirring at 1200 rpm for 10 minutes to obtain mixture 2;

[0058] S4, uniformly coating a 3% paraffin solution on the surface of 0.4 parts of the ceramic fiber, and drying the coated ceramic fiber at 180° C. for 2 hours to remove the solvent and form a stable lubricating layer, thereby obtaining a ceramic fiber containing a lubricating layer;

[0059] S5. Add the ceramic fiber containing the lubricating layer obtained in S4 to the mixture 2 obtained in S3, and shear and stir at 600 rpm for 10 minutes to prepare a high-toughness active cooling asphalt mortar.

[0060] The preparation method of the montmorillonite-SAP composite material is as follows:

[0061] First, the modified montmorillonite was prepared as follows: (1) 10.0 parts of sodium montmorillonite was placed in a beaker containing deionized water to prepare a suspension, and ultrasonic treatment was performed at 40 kHz for 30 min to improve the dispersibility of the montmorillonite; (2) 1.0 part of dodecyltrimethylammonium bromide was slowly added dropwise and stirred at 450 rpm for 1.3 h; (3) the mixture was centrifuged and filtered, and then washed three times with deionized water to remove unreacted impurities; (4) the obtained material was dried in a vacuum drying oven at 70°C for 5 h and ground into a 200-300 mesh powder, which is the modified montmorillonite;

[0062] Then, montmorillonite-SAP composite material was prepared: (1) 31.2 parts of acrylic acid were added to a beaker, and a 25% by mass acrylic acid solution was prepared with deionized water. A 30% by mass sodium hydroxide (NaOH) solution was slowly added dropwise to adjust the pH to 7; (2) 6.0 parts of the prepared modified montmorillonite were gradually added, and magnetic stirring was carried out at 300 rpm for 25 minutes, and then the mixture was placed in a water bath at 55°C for 20 minutes; (3) 0.8 parts of potassium persulfate were added to the mixture, and magnetic stirring was carried out at 300 rpm for 15 minutes. in to promote free radical polymerization reaction; (4) increase the water bath temperature to 75℃, continue stirring for 15 minutes, and at the same time add 0.02 parts of N,N'-methylenebisacrylamide dropwise to react and form a stable montmorillonite-SAP composite gel material; (5) place the beaker in a 0℃ ice water bath and let it stand for 7 hours to promote the stabilization of the polymer chain material; (6) wash with deionized water 6 times to remove unreacted substances, and then dry in a vacuum drying oven at 55℃ for 5 hours; (7) grind to 100-300 mesh powder after drying to obtain a montmorillonite-SAP composite material.

[0063] Example 4

[0064] This embodiment is a high-toughness active cooling asphalt mortar, which includes the following raw materials according to mass measurement: 70 parts of AH-90 matrix asphalt, 37.5 parts of mineral powder, 0.5 parts of ceramic fiber, and 45 parts of montmorillonite-SAP composite material.

[0065] The preparation method of the high-toughness active cooling asphalt mortar comprises the following steps:

[0066] S1. Heat 70 parts of base asphalt in an oven to 170°C and continuously stir magnetically at 650 rpm for 4 minutes to maintain uniform fluidity.

[0067] S2. Gradually add 37.5 parts of mineral powder to the base asphalt treated in S1, and perform high-speed shear stirring at 1100 rpm for 12 minutes to obtain mixture 1;

[0068] S3. Slowly add 45 parts of montmorillonite-SAP composite material to the mixture 1 obtained in S2, and continue high-speed shear stirring at 1100 rpm for 12 minutes to obtain mixture 2;

[0069] S4, uniformly coating a 3% paraffin solution on the surface of 0.5 parts of the ceramic fiber, and drying the coated ceramic fiber at 180° C. for 2 hours to remove the solvent and form a stable lubricating layer, thereby obtaining a ceramic fiber containing a lubricating layer;

[0070] S5. Add the ceramic fiber containing the lubricating layer obtained in S4 to the mixture 2 obtained in S3, and shear and stir at 650 rpm for 12 minutes to prepare a high-toughness active cooling asphalt mortar.

[0071] The preparation method of the montmorillonite-SAP composite material is as follows:

[0072] First, the modified montmorillonite was prepared as follows: (1) 9.0 parts of sodium montmorillonite was placed in a beaker containing deionized water to prepare a suspension, and ultrasonic treatment was performed at 40 kHz for 30 min to improve the dispersibility of the montmorillonite; (2) 1.0 part of dodecyltrimethylammonium bromide was slowly added dropwise and stirred at 500 rpm for 1.4 h; (3) the mixture was centrifuged and filtered, and then washed three times with deionized water to remove unreacted impurities; (4) the obtained material was dried in a vacuum drying oven at 75°C for 5 h and ground into a 200-300 mesh powder, which is the modified montmorillonite;

[0073] Then, a montmorillonite-SAP composite material was prepared: (1) 31.2 parts of acrylic acid were added to a beaker, and a 25% by mass acrylic acid solution was prepared with deionized water. A 45% by mass sodium hydroxide (NaOH) solution was slowly added dropwise to adjust the pH to 7; (2) 6.75 parts of the prepared modified montmorillonite were gradually added, and magnetic stirring was carried out at 400 rpm for 15 minutes, and then the mixture was placed in a water bath at 60°C for 20 minutes; (3) 0.9 parts of potassium persulfate were added to the mixture, and magnetic stirring was carried out at 200 rpm for 15 minutes. , to promote free radical polymerization reaction; (4) increase the water bath temperature to 80℃, continue stirring for 20 minutes, and at the same time, add 0.0225 parts of N,N'-methylenebisacrylamide dropwise to react to form a stable montmorillonite-SAP composite gel material; (5) place the beaker in a 0℃ ice water bath and let it stand for 8 hours to promote the stabilization of the polymer chain material; (6) wash with deionized water 5 times to remove unreacted substances, and then dry in a vacuum drying oven at 55℃ for 5.5 hours; (7) after drying, grind to 100-300 mesh powder to obtain montmorillonite-SAP composite material.

[0074] Example 5

[0075] This embodiment is a high-toughness active cooling asphalt mortar, which includes the following raw materials according to mass measurement: 85 parts of AH-70 matrix asphalt, 45 parts of mineral powder, 0.2 parts of ceramic fiber, and 30 parts of montmorillonite-SAP composite material.

[0076] The preparation method of the high-toughness active cooling asphalt mortar comprises the following steps:

[0077] S1. Heat 85 parts of base asphalt in an oven to 160°C and continuously stir magnetically at 700 rpm for 5 minutes to maintain uniform fluidity.

[0078] S2. Gradually add 45 parts of mineral powder to the base asphalt treated in S1, and perform high-speed shear stirring at 1000 rpm for 15 minutes to obtain mixture 1;

[0079] S3. Slowly add 30 parts of montmorillonite-SAP composite material to the mixture 1 obtained in S2, and continue high-speed shear stirring at 1000 rpm for 15 minutes to obtain mixture 2;

[0080] S4, uniformly coating 0.2 parts of the ceramic fiber surface with a 3% paraffin solution, and drying the coated ceramic fiber at 180° C. for 2 hours to remove the solvent and form a stable lubricating layer, thereby obtaining a ceramic fiber containing a lubricating layer;

[0081] S5. Add the ceramic fiber containing the lubricating layer obtained in S4 to the mixture 2 obtained in S3, and shear and stir at 700 rpm for 10 minutes to prepare a high-toughness active cooling asphalt mortar.

[0082] The preparation method of the montmorillonite-SAP composite material is as follows:

[0083] First, the modified montmorillonite was prepared as follows: (1) 9.0 parts of sodium montmorillonite was placed in a beaker containing deionized water to prepare a suspension, and ultrasonic treatment was performed at 40 kHz for 30 minutes to improve the dispersibility of the montmorillonite; (2) 1.0 parts of hexadecyltrimethylammonium bromide was slowly added dropwise and stirred at 400 rpm for 1.5 hours; (3) the suspension was centrifuged and filtered, and then washed three times with deionized water to remove unreacted impurities; (4) the obtained material was dried in a vacuum drying oven at 60°C for 6 hours and ground into a 200-300 mesh powder, which is the modified montmorillonite;

[0084] Then, montmorillonite-SAP composite material was prepared: (1) 23.4 parts of acrylic acid were added to a beaker, and a 25% by mass acrylic acid solution was prepared with deionized water, and a 35% by mass sodium hydroxide (NaOH) solution was slowly added dropwise to adjust the pH to 7; (2) 4.5 parts of the prepared modified montmorillonite were gradually added, and magnetic stirring was carried out at 400 rpm for 15 minutes, and then the mixture was placed in a 50°C water bath for 20 minutes; (3) 0.6 parts of potassium persulfate were added to the mixture, and magnetic stirring was carried out at 400 rpm for 10 minutes. n, to promote free radical polymerization reaction; (4) increase the water bath temperature to 80℃, continue stirring for 15 minutes, and at the same time, add 0.015 parts of N,N'-methylenebisacrylamide dropwise to react and form a stable montmorillonite-SAP composite gel material; (5) place the beaker in a 0℃ ice water bath and let it stand for 8 hours to promote the stabilization of the polymer chain material; (6) wash with deionized water 5 times to remove unreacted substances, and then dry in a vacuum drying oven at 50℃ for 6 hours; (7) after drying, grind to 100-300 mesh powder to obtain a montmorillonite-SAP composite material.

[0085] Example 6

[0086] This embodiment is a high-toughness active cooling asphalt mortar, which includes the following raw materials according to mass measurement: 85 parts of AH-70 matrix asphalt, 45 parts of mineral powder, 0.2 parts of ceramic fiber, and 30 parts of montmorillonite-SAP composite material.

[0087] The preparation method of the high-toughness active cooling asphalt mortar comprises the following steps:

[0088] S1. Heat 85 parts of base asphalt in an oven to 160°C and continuously stir magnetically at 700 rpm for 5 minutes to maintain uniform fluidity.

[0089] S2. Gradually add 45 parts of mineral powder to the base asphalt treated in S1, and perform high-speed shear stirring at 1000 rpm for 15 minutes to obtain mixture 1;

[0090] S3. Slowly add 30 parts of montmorillonite-SAP composite material to the mixture 1 obtained in S2, and continue high-speed shear stirring at 1000 rpm for 15 minutes to obtain mixture 2;

[0091] S4, uniformly coating 0.2 parts of the ceramic fiber surface with a 3% paraffin solution, and drying the coated ceramic fiber at 180° C. for 2 hours to remove the solvent and form a stable lubricating layer, thereby obtaining a ceramic fiber containing a lubricating layer;

[0092] S5. Add the ceramic fiber containing the lubricating layer obtained in S4 to the mixture 2 obtained in S3, and shear and stir at 700 rpm for 10 minutes to prepare a high-toughness active cooling asphalt mortar.

[0093] The preparation method of the montmorillonite-SAP composite material is as follows:

[0094] First, the modified montmorillonite was prepared as follows: (1) 9.0 parts of sodium montmorillonite was placed in a beaker containing deionized water to prepare a suspension, and ultrasonic treatment was performed at 40 kHz for 30 minutes to improve the dispersibility of the montmorillonite; (2) 1.0 parts of dodecyltrimethylammonium bromide was slowly added dropwise and stirred at 400 rpm for 1.5 hours; (3) the mixture was centrifuged and filtered, and then washed three times with deionized water to remove unreacted impurities; (4) the obtained material was dried in a vacuum drying oven at 60°C for 6 hours and ground into a powder of 200-300 mesh, which is the modified montmorillonite;

[0095] Then, montmorillonite-SAP composite material was prepared: (1) 23.4 parts of acrylamide were added to a beaker, and a 30% acrylamide solution was prepared with deionized water. A 35% sodium hydroxide (NaOH) solution was slowly added dropwise to adjust the pH to 7; (2) 4.5 parts of the prepared modified montmorillonite were gradually added, and magnetic stirring was carried out at 400 rpm for 15 minutes, and then the mixture was placed in a 50°C water bath for 20 minutes; (3) 0.6 parts of potassium persulfate were added to the mixture, and magnetic stirring was carried out at 400 rpm for 10 minutes. in to promote free radical polymerization reaction; (4) increase the water bath temperature to 80℃, continue stirring for 15 minutes, and at the same time add 0.015 parts of N,N'-methylenebisacrylamide dropwise to react and form a stable montmorillonite-SAP composite gel material; (5) place the beaker in a 0℃ ice water bath and let it stand for 8 hours to promote the stabilization of the polymer chain material; (6) wash with deionized water 5 times to remove unreacted substances, and then dry in a vacuum drying oven at 50℃ for 6 hours; (7) grind to 100-300 mesh powder after drying to obtain a montmorillonite-SAP composite material.

[0096] Comparative Example 1

[0097] The preparation of asphalt mortar without adding montmorillonite-SAP composite material and ceramic fiber includes the following steps:

[0098] S1. Heat 85 parts of AH-70 matrix asphalt in an oven to 160°C and continuously stir magnetically at 700 rpm for 5 minutes to maintain uniform fluidity.

[0099] S2. Gradually add 75 parts of mineral powder to the base asphalt treated in S1, and perform high-speed shear stirring at 1000 rpm for 15 minutes to prepare the asphalt mortar material.

[0100] In order to verify the cooling effect of the high-toughness active cooling asphalt mortar provided by the present invention, referring to the relevant provisions of the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011), the high-toughness active cooling asphalt mortars obtained in Examples 1 to 6 and the asphalt mortar obtained in Comparative Example 1 were used to prepare AC-16 asphalt mixture, and the method is as follows: (1) weighing the coarse and fine aggregates required by the test, heating them to 170-180°C, and maintaining them at a constant temperature for 2-4 hours; (2) pouring the heated aggregates into a mixing pot or an intermittent mixer, starting the stirring device, and stirring them thoroughly; (3) slowly pouring the prepared asphalt mortar (temperature 160-170°C, oil-to-stone ratio of 4.0%) and mixing them for 30-60 seconds, and then the asphalt mixture can be obtained after the molding process.

[0101] The AC-16 asphalt mixture prepared using the asphalt mortar of Examples 1 to 6 and Comparative Example 1 was further made into a rutting board with a size of 30 cm*30 cm*5 cm. Temperature sensors were placed on the surface, 5 cm away, and at the bottom of the rutting board. The specimen was moved into a homemade test box, and a 500W iodine tungsten lamp was used to simulate the sunlight light source and placed on the upper part of the specimen. The light source was turned on for irradiation, and a thermometer was used to read the sensor temperature during the irradiation process.

[0102] Figure 1 and Figure 2 The invention relates to a heating process of a rutting plate made of the asphalt mortar prepared by the invention and a temperature measurement process of each layer of the rutting plate.

[0103] Tables 1 to 3 are the test results of temperature changes on the surface, 5 cm away and at the bottom of the rutting plate respectively.

[0104] Table 1 Test results of surface temperature change of rutting plate

[0105]

[0106] Table 2 Test results of temperature change at 5 cm from the rutting plate

[0107]

[0108] Table 3 Test results of temperature change at the bottom of the rutting plate

[0109]

[0110]

[0111] In order to verify the improvement effect of the high-toughness active cooling asphalt mortar prepared by the present invention on the low-temperature crack resistance compared to ordinary asphalt mortar, referring to the relevant provisions of the AASHTO T313 standard, 6.35mm (thickness) × 12.7mm (width) × 127mm (length) asphalt mortar beam specimens were prepared using the asphalt mortars of Examples 1 to 6 and Comparative Example 1, and the BBR test was performed using a CANNON low-temperature bending rheometer to test its stiffness modulus and creep rate. Among them, the greater the stiffness modulus, the harder the asphalt mortar and the worse the low-temperature crack resistance; the greater the creep rate, the better the toughness of the asphalt mortar, the better the stress relaxation ability, and the less likely it is to crack in a low-temperature environment. The specific test results are shown in Table 4.

[0112] Table 4 Test results of high-toughness active cooling asphalt mortar BBR

[0113]

[0114] To verify the improved high-toughness active cooling asphalt mortar prepared by the present invention compared to conventional asphalt mortar in terms of high-temperature deformation resistance, in accordance with the relevant provisions of the AASHTO T315 standard, asphalt mortar samples of 25 mm (diameter) × 1 mm (thickness) were prepared using the asphalt mortars of Examples 1 to 6 and Comparative Example 1. DSR tests were performed using a Malvern dynamic shear rheometer to measure the complex shear modulus and phase angle. A larger complex shear modulus indicates greater rigidity and stronger resistance to deformation; a larger phase angle indicates poorer elasticity and greater susceptibility to flow deformation. The specific test results are shown in Table 5.

[0115] Table 5 DSR test results of high-toughness active cooling asphalt mortar

[0116]

[0117]

[0118] The present invention provides a high-toughness active cooling asphalt mortar and a preparation method thereof. The asphalt mortar uses matrix asphalt, mineral powder, ceramic fiber and montmorillonite-SAP composite material as raw materials. The preparation process is simple. The obtained asphalt mortar can not only effectively reduce the temperature of the asphalt pavement and effectively reduce rutting and other diseases caused by high temperature of the pavement in summer, but also significantly improve its own toughness, thereby improving the fatigue resistance of the asphalt pavement structure.

[0119] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent variation made to the above embodiment based on the essence of the invention technology shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A high-toughness active cooling asphalt mortar, characterized in that: The asphalt mortar comprises the following raw materials in parts by weight: 70 to 85 parts of matrix asphalt, 37.5 to 45 parts of mineral powder, 0.2 to 0.5 parts of ceramic fiber, and 30 to 45 parts of montmorillonite-SAP composite material.

2. The asphalt mortar according to claim 1, characterized in that The matrix asphalt is AH-70 or AH-90; The length of the ceramic fiber is 3 to 10 mm; The mineral powder is limestone powder or silicate mineral powder, and its particle size distribution satisfies: the mass percentage passing through a 0.075mm sieve is ≥85%, and the specific surface area is 350-550m 2 / kg.

3. The asphalt mortar according to claim 1, characterized in that The preparation method of the montmorillonite-SAP composite material is: An organic matrix is ​​prepared into a solution with deionized water, the pH is adjusted to 7, and then modified montmorillonite is added, and the mixture is stirred at 200-400 rpm for 15-30 minutes, and then placed in a water bath at 50-60°C for 15-20 minutes to obtain a mixed solution; an initiator is added to the mixed solution, and the mixture is stirred at 200-400 rpm for 10-15 minutes to promote a free radical polymerization reaction; the water bath temperature is increased to 70-80°C, and stirring is continued for 15-20 minutes, while a cross-linking agent is added dropwise to react to form a stable montmorillonite-SAP composite gel-like material, which is then placed in an ice water bath at 0°C for 6-8 hours to promote the stabilization of the polymer chain material; unreacted substances are washed away with deionized water, and the mixture is dried and ground to obtain a montmorillonite-SAP composite material.

4. The asphalt mortar according to claim 3, characterized in that The preparation method of the modified montmorillonite is: Montmorillonite is added to deionized water and uniformly dispersed by ultrasonication to prepare a suspension; an organic modifier is then added dropwise to the suspension, and the mixture is stirred at 400-500 rpm for 1.2-1.5 hours. The resulting mixture is centrifuged and washed, and then vacuum-dried at 60-80°C for 4-6 hours, and ground into a 200-300 mesh powder to obtain the modified montmorillonite; The montmorillonite is sodium montmorillonite with a particle size of 100 to 300 μm and a specific surface area of ​​50 to 150 m 2 / g; The organic modifier is one of dodecyltrimethylammonium bromide and hexadecyltrimethylammonium bromide, and the mass ratio of the montmorillonite to the organic modifier is (8-10):

1.

5. The asphalt mortar according to claim 3, characterized in that The organic matrix is ​​acrylic acid or acrylamide, and the neutralizing solution used for adjusting pH is sodium hydroxide solution with a mass fraction of 30% to 45%.

6. The asphalt mortar according to claim 3, characterized in that The initiator is potassium persulfate.

7. The asphalt mortar according to claim 3, characterized in that The cross-linking agent is N,N'-methylenebisacrylamide.

8. The asphalt mortar according to claim 3, characterized in that The mass ratio of the organic matrix, the modified montmorillonite, the initiator and the crosslinking agent is (23.4-31.2): (4.5-6.75): (0.6-0.9): (0.015-0.0225).

9. The asphalt mortar according to claim 3, characterized in that The montmorillonite-SAP composite material was obtained by washing with deionized water for 5 to 7 times to remove unreacted substances, drying in a vacuum drying oven at 50 to 55° C. for 4 to 6 hours, and grinding into 100 to 300 mesh powder.

10. A method for preparing the high-toughness active cooling asphalt mortar according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Heat the base asphalt to 160-170°C and stir continuously at 500-700 rpm for 3-5 minutes to maintain uniform fluidity; S2. Add mineral powder to the base asphalt treated in S1, and stir at a high speed of 1000-1200 rpm for 10-15 minutes to obtain mixture 1; S3, adding the montmorillonite-SAP composite material to the mixture 1 obtained in S2, and continuing high-speed shear stirring at 1000-1200 rpm for 10-15 minutes to obtain a mixture 2; S4. Uniformly coating the surface of the ceramic fiber with a lubricant, and then drying the ceramic fiber at 180° C. for 2 hours to remove the solvent and form a stable lubricating layer, thereby obtaining a ceramic fiber comprising a lubricating layer; the lubricant is a 3% by mass paraffin solution; S5. Add the ceramic fiber containing the lubricating layer obtained in S4 to the mixture 2 obtained in S3, and shear and stir at 500-700 rpm for 10-15 minutes to prepare a high-toughness active cooling asphalt mortar.

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