Durable recycled rubber asphalt and preparation method thereof

Abstract

The invention discloses a durable regenerated rubber asphalt and a preparation method thereof, and relates to the technical field of rubber asphalt preparation. The present invention first realizes chloropalm oil methyl ester coating diatomaceous earth through surface tension and capillary action, so that it is converted into hydrophobicity, improves cold resistance, and at the same time, the diatomaceous earth has a low thermal conductivity, achieving a flame retardant effect; then combined with phosphorus enol pyruvic acid to prepare a modified powder, introduces phosphorus element, and decomposes to produce substances such as phosphorus oxyacid and phosphate during combustion to achieve a flame retardant effect; then vinyl trihydroxy silane is combined with asphalt to prepare a modified asphalt, forming a stable network structure, improving heat resistance, while introducing a longer Si-O bond, reducing low-temperature molecular agglomeration, and improving low-temperature resistance; finally, the unsaturated double bond in the modified asphalt is combined with the activated powder and the rubber powder by addition reaction to form a cross-linked structure to achieve heat resistance, cold resistance, and flame retardant effects.

Description

Technical Field

[0001] The present invention relates to the technical field of rubber asphalt preparation, in particular to a durable regenerated rubber asphalt and a preparation method thereof. Background Art

[0002] Asphalt pavement has become the main type of highway pavement structure in my country due to its good road performance, comfortable driving environment and high economy. However, at the same time, due to the continuous increase in traffic volume, large and heavy vehicles have put forward higher requirements for highway pavements. How to improve the structural performance of asphalt pavements, such as high and low temperature stability, water stability, and fatigue resistance, is an urgent problem that needs to be solved in the current asphalt pavement design. Among the many modified asphalts, rubber modified asphalt has always been a hot research direction. Compared with SBS modified asphalt, rubber asphalt has the advantages of relatively low price, easy availability of modifiers, and easier process preparation. In addition, rubber asphalt has advantages that other modified asphalts do not have in improving road noise and improving driving comfort.

[0003] Because rubber undergoes oxidation reactions in the presence of sunlight and oxygen, rubber asphalt pavement materials age over time, significantly reducing their elasticity and viscosity, which in turn affects the pavement's service life and performance. Rubber asphalt is particularly susceptible to aging in areas with significant temperature fluctuations. Currently, research on the regeneration of rubber-modified asphalt is still in its early stages. Therefore, developing a highly durable recycled rubber asphalt has significant economic and theoretical value. Summary of the Invention

[0004] The purpose of the present invention is to provide a durable regenerated rubber asphalt and a preparation method thereof to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a durable regenerated rubber asphalt, wherein the durable regenerated rubber asphalt is prepared by a mixed reaction of modified asphalt, rubber powder, and modified powder.

[0006] Furthermore, the asphalt is prepared from vinyl trihydroxysilane and base asphalt.

[0007] Furthermore, the matrix asphalt is any one of 70# heavy traffic asphalt and 90# heavy traffic asphalt.

[0008] Furthermore, the rubber powder is 40-60 mesh waste tire powder.

[0009] Furthermore, the modified powder is prepared from diatomaceous earth, chloropalm oil methyl ester and phosphoenolpyruvic acid.

[0010] Furthermore, a method for preparing durable recycled rubber asphalt comprises the following preparation steps:

[0011] (1) 12 to 24 parts of diatomaceous earth were placed in a muffle furnace and calcined at 350 to 450°C for 1 to 2 hours, cooled to 30 to 40°C, added with 60 to 120 parts of anhydrous ethanol, ultrasonicated for 1 to 2 hours, filtered to obtain the solid, washed with deionized water three times, dried at 50 to 60°C for 8 to 12 hours, added with 48 to 96 parts of petroleum ether and 10 to 20 parts of chloropalm oil methyl ester, stirred at 55 to 65°C and 1000 rpm for 1 to 2 hours, heated to 70 to 80°C, continued to stir for 3 to 5 hours, filtered to obtain the solid, and dried at 80 to 90°C for 10 to 16 hours to obtain modified diatomaceous earth;

[0012] (2) Add 6-12 parts of phosphoenolpyruvic acid and 9-17 parts of triethylamine to 14-28 parts of modified diatomaceous earth under stirring at 60 rpm, react for 0.5-1.5 hours, filter and collect the solid, wash it with deionized water three times, and dry it at 60-70°C for 5-9 hours to obtain a modified powder;

[0013] (3) heating 110-150 parts of base asphalt to 130-140°C, stirring at 800 rpm for 10-20 minutes, adding 3-9 parts of vinyl trihydroxysilane dropwise, and continuing stirring for 1-2 hours to obtain modified asphalt;

[0014] (4) Place 93-117 parts of modified asphalt in a high-speed shearing machine, add 186-234 parts of ethanol, 5-18 parts of modified powder, and 1-3 parts of catalyst while stirring at 600 rpm, add 40-60 mesh rubber powder three times, 6-8 parts each time, react for 5-9 hours, heat to 170-190°C, accelerate stirring to 4000 rpm at a certain rate, continue for 60-80 minutes, then stir at 300 rpm for 2-4 hours, cool to 20-30°C, and obtain durable recycled rubber asphalt.

[0015] Furthermore, the frequency of the ultrasound in step (1) is 60 to 80 kHz.

[0016] Furthermore, the dripping rate in step (3) is 1 drop / s.

[0017] Furthermore, the catalyst in step (4) is any one of boron trifluoride, tributyl boron, and titanium tetrachloride.

[0018] Furthermore, the stirring speed in step (4) is accelerated to 340 r / min.

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

[0020] First, the present invention fully contacts chloropalm oil methyl ester through the pore structure of diatomaceous earth, and achieves chloropalm oil methyl ester coating of diatomaceous earth under surface tension and capillary action, thereby improving the flexibility and elasticity of the material in a cold environment, preventing the material from becoming brittle and cracking at low temperatures, and enhancing durability. At the same time, the palm oil coating changes the diatomaceous earth from hydrophilic to hydrophobic, blocking the entry of water, thereby achieving an antifreeze effect. On this basis, the diatomaceous earth, the main component of which is silicon dioxide, has a low thermal conductivity, thereby effectively blocking the transfer of heat, thereby achieving a flame retardant effect. Then, the chlorine groups in the diatomaceous earth are combined with the hydroxyl groups of phosphoenolpyruvic acid to prepare a modified powder, and phosphorus is introduced. During combustion, the modified powder decomposes to produce substances such as phosphorus oxyacid and phosphate esters, which can react with hydrogen and free radicals to form non-combustion products such as phosphates and phosphate ester salts, thereby suppressing the spread of flames, thereby achieving a flame retardant effect.

[0021] Secondly, modified asphalt is prepared by combining vinyl trihydroxysilane with asphalt to form a stable network structure, which improves the elasticity of asphalt at high temperatures, thereby improving the high temperature resistance. At the same time, longer Si-O bonds are introduced to increase the flexibility of the material, reduce low-temperature molecular agglomeration, and improve low-temperature resistance, thereby achieving high durability. Finally, the unsaturated double bonds in the modified asphalt are combined with the activated powder and rubber powder through addition reactions to form a cross-linked structure to achieve heat resistance, cold resistance, and flame retardant effects. DETAILED DESCRIPTION

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

[0023] In order to more clearly illustrate the method provided by the present invention, the following examples are provided in detail. The test methods for various indicators of the durable regenerated rubber asphalt prepared in the following examples are as follows:

[0024] Softening point: Take the same mass of the embodiment and the comparative example and measure it in accordance with GB / T 4507.

[0025] Freeze-thaw splitting residual strength ratio: Take the same mass of the embodiment and the comparative example and measure it according to the method T0729-2000 in JTJ052-2000 "Test Procedure for Asphalt and Asphalt Mixture in Highway Engineering".

[0026] Fatigue test: Take the same mass of the embodiment and the comparative example and measure it according to NF P98

[0027] Oxygen index: measured according to NB / SH / T 0815 on the same mass of the examples and comparative examples.

[0028] Example 1

[0029] (1) 12 parts of diatomaceous earth were placed in a muffle furnace and calcined at 350°C for 1 hour, cooled to 30°C, added with 60 parts of anhydrous ethanol, ultrasonicated at 60kHz for 1 hour, filtered to obtain the solid, washed with deionized water 3 times, dried at 50°C for 8 hours, added with 48 parts of petroleum ether and 10 parts of chloropalm oil methyl ester, stirred at 55°C and 1000 rpm for 1 hour, heated to 70°C, continued to stir for 3 hours, filtered to obtain the solid, and dried at 80°C for 10 hours to obtain modified diatomaceous earth;

[0030] (2) 6 parts of phosphoenolpyruvic acid and 9 parts of triethylamine were added to 14 parts of modified diatomaceous earth under stirring at 60 rpm, and the reaction was carried out for 0.5 h. The solid was filtered, washed with deionized water three times, and dried at 60°C for 5 h to obtain a modified powder;

[0031] (3) Heat 110 parts of 90# heavy traffic asphalt to 130°C, stir at 800 rpm for 10 min, add 3 parts of vinyl trihydroxysilane dropwise at a rate of 1 drop / s, and continue stirring for 1 h to obtain modified asphalt;

[0032] (4) Place 93 parts of modified asphalt in a high-speed shearing machine, add 186 parts of ethanol, 5 parts of modified powder, and 1 part of boron trifluoride while stirring at 600 rpm, add 40-mesh rubber powder three times, 6 parts each time, react for 5 hours, heat to 170°C, accelerate stirring to 4000 rpm at 340 r / min, continue for 60 minutes, then stir at 300 rpm for 2 hours, cool to 20°C, and obtain durable recycled rubber asphalt.

[0033] Example 2

[0034] (1) 18 parts of diatomaceous earth were placed in a muffle furnace and calcined at 400°C for 1.5 hours, cooled to 35°C, added with 90 parts of anhydrous ethanol, ultrasonicated at 70kHz for 1.5 hours, filtered to obtain the solid, washed three times with deionized water, dried at 55°C for 10 hours, added with 72 parts of petroleum ether and 15 parts of chloropalm oil methyl ester, stirred at 60°C and 1000 rpm for 1.5 hours, heated to 75°C, continued to stir for 4 hours, filtered to obtain the solid, and dried at 85°C for 13 hours to obtain modified diatomaceous earth;

[0035] (2) 8 parts of phosphoenolpyruvic acid and 13 parts of triethylamine were added to 21 parts of modified diatomaceous earth under stirring at 60 rpm, and the reaction was carried out for 1.0 h. The solid was filtered, washed with deionized water three times, and dried at 65°C for 7 h to obtain a modified powder;

[0036] (3) Heat 130 parts of 70# heavy traffic asphalt to 135°C, stir at 800 rpm for 15 min, add 6 parts of vinyl trihydroxysilane at a rate of 1 drop / s, and continue stirring for 1.5 h to obtain modified asphalt;

[0037] (4) Place 105 parts of modified asphalt in a high-speed shearing machine, add 210 parts of ethanol, 12 parts of modified powder, and 2 parts of tributyl boron while stirring at 600 rpm, add 50-mesh rubber powder three times, 7 parts each time, react for 7 hours, heat to 180°C, accelerate stirring to 4000 rpm at 340 r / min, continue for 70 minutes, then stir at 300 rpm for 3 hours, cool to 25°C, and obtain durable recycled rubber asphalt.

[0038] Example 3

[0039] (1) 24 parts of diatomaceous earth were placed in a muffle furnace and calcined at 450°C for 2 hours, cooled to 40°C, added with 120 parts of anhydrous ethanol, ultrasonicated at 80kHz for 2 hours, filtered to obtain the solid, washed with deionized water three times, dried at 60°C for 12 hours, added with 96 parts of petroleum ether and 20 parts of chloropalm oil methyl ester, stirred at 65°C and 1000 rpm for 2 hours, heated to 80°C, continued to stir for 5 hours, filtered to obtain the solid, and dried at 90°C for 16 hours to obtain modified diatomaceous earth;

[0040] (2) 12 parts of phosphoenolpyruvic acid and 17 parts of triethylamine were added to 28 parts of modified diatomaceous earth under stirring at 60 rpm, and the reaction was carried out for 1.5 hours. The solid was filtered, washed with deionized water three times, and dried at 70°C for 9 hours to obtain a modified powder;

[0041] (3) Heat 150 parts of 70# heavy traffic asphalt / 90# heavy traffic asphalt to 140°C, stir at 800 rpm for 20 min, add 9 parts of vinyl trihydroxysilane at a rate of 1 drop / s, and continue stirring for 2 h to obtain modified asphalt;

[0042] (4) Place 117 parts of modified asphalt in a high-speed shearing machine, add 234 parts of ethanol, 18 parts of modified powder, and 3 parts of titanium tetrachloride while stirring at 600 rpm, add 60-mesh rubber powder three times, 8 parts each time, react for 9 hours, heat to 190°C, accelerate stirring to 4000 rpm at 340 r / min, continue for 80 minutes, then stir at 300 rpm for 4 hours, cool to 30°C, and obtain durable recycled rubber asphalt.

[0043] Comparative Example 1

[0044] Comparative Example 1 differs from Example 1 in that step (1) is omitted, and step (2) is modified as follows: 8 parts of phosphoenolpyruvic acid and 13 parts of triethylamine are added to 21 parts of chloropalm oil methyl ester while stirring at 60 rpm, and the reaction is carried out for 1.0 h. The solid is filtered, washed three times with deionized water, and dried at 65° C. for 7 h to obtain a modified powder. The remaining steps are the same as those of Example 2.

[0045] Comparative Example 2

[0046] Comparative Example 2 differs from Example 2 in that step (1) is omitted, and step (2) is modified as follows: 8 parts of phosphoenolpyruvic acid and 13 parts of triethylamine are added to 21 parts of diatomaceous earth while stirring at 60 rpm, and the reaction is carried out for 1.0 h. The solid is filtered, washed three times with deionized water, and dried at 65° C. for 7 h to obtain a modified powder. The remaining steps are the same as in Example 2.

[0047] Comparative Example 3

[0048] Comparative Example 3 differs from Example 1 in that step (2) is omitted, and step (4) is modified as follows: 105 parts of 70# base asphalt are placed in a high-speed shearing machine, and 210 parts of ethanol, 12 parts of modified diatomaceous earth, and 2 parts of tributyl boron are added while stirring at 600 rpm. 50-mesh rubber powder is then added in three portions, 7 parts each time, for a reaction of 7 hours. The mixture is then heated to 180°C, stirred at 340 rpm to 4000 rpm for 70 minutes, then stirred at 300 rpm for 3 hours, and cooled to 25°C to obtain a durable regenerated rubber asphalt. The remaining steps are the same as in Example 2.

[0049] Comparative Example 4

[0050] Comparative Example 4 differs from Example 1 in that step (3) is omitted. Step (4) is modified as follows: 105 parts of 70# base asphalt are placed in a high-speed shearing machine, stirred at 600 rpm, 210 parts of ethanol, 12 parts of modified powder, and 2 parts of tributyl boron are added, and 50-mesh rubber powder is added in three portions, 7 parts each time, for 7 hours. The mixture is heated to 180°C, stirred at 340 rpm to 4000 rpm for 70 minutes, then stirred at 300 rpm for 3 hours, and cooled to 25°C to obtain durable regenerated rubber asphalt. The remaining steps are the same as those in Example 2.

[0051] Effect Examples

[0052] Table 1 below shows the performance analysis results of the durable regenerated rubber asphalt using Examples 1 to 3 of the present invention and Comparative Examples 1 to 4.

[0053] Table 1

[0054]

[0055]

[0056] From the comparison of the experimental data of Examples 1, 2, and 3 with Comparative Example 1, it can be found that the main component of diatomaceous earth is silicon dioxide, which has a low thermal conductivity and can effectively block the transfer of heat, thereby achieving flame retardant and heat-resistant effects; from the comparison of the experimental data of Examples 1, 2, and 3 with Comparative Example 2, it can be found that chloropalm oil methyl ester successfully coats diatomaceous earth under surface tension and capillary action, significantly improving the flexibility and elasticity of the material in a cold environment, preventing the material from becoming brittle and cracking at low temperatures. At the same time, the palm oil coating changes the diatomaceous earth from hydrophilic to hydrophobic, blocking water from entering, thereby achieving an antifreeze effect ... Compared with the experimental data of Comparative Example 3, it can be found that the introduction of phosphorus element through phosphoenolpyruvate decomposes during combustion to produce substances such as phosphorus oxide and phosphate esters, which can react with hydrogen and free radicals to form non-combustible products such as phosphates and phosphate ester salts, thereby inhibiting the spread of flame and achieving a flame retardant effect; from the comparison of the experimental data of Examples 1, 2, and 3 with Comparative Example 4, it can be found that the addition of vinyl trihydroxy silane can form a stable network structure, improve the elasticity of asphalt at high temperatures, thereby improving the high temperature resistance effect, and at the same time introduce longer Si-O bonds, improve the flexibility of the material, reduce low-temperature molecular agglomeration, and improve cold resistance.

[0057] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed therein. Any reference in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A method for preparing durable recycled rubber asphalt, characterized in that: The method comprises the following preparation steps: (1) Place 12-24 parts of diatomaceous earth in a muffle furnace and calcine at 350-450°C for 1-2 hours, cool to 30-40°C, add 60-120 parts of anhydrous ethanol, ultrasonicate for 1-2 hours, filter out the solid, wash with deionized water 3 times, dry at 50-60°C for 8-12 hours, add 48-96 parts of petroleum ether and 10-20 parts of chloropalm oil methyl ester, stir at 55-65°C and 1000 rpm for 1-2 hours, heat to 70-80°C, continue stirring for 3-5 hours, filter out the solid, and dry at 80-90°C for 10-16 hours to obtain modified diatomaceous earth; (2) Add 6-12 parts of phosphoenolpyruvic acid and 9-17 parts of triethylamine to 14-28 parts of modified diatomaceous earth under stirring at 60 rpm, react for 0.5-1.5 hours, filter and collect the solid, wash it with deionized water three times, and dry it at 60-70 ° C for 5-9 hours to obtain a modified powder; (3) Heat 110-150 parts of base asphalt to 130-140°C, stir at 800 rpm for 10-20 min, add 3-9 parts of vinyl trihydroxysilane dropwise, and continue stirring for 1-2 h to obtain modified asphalt; (4) Place 93-117 parts of modified asphalt in a high-speed shearing machine, add 186-234 parts of ethanol, 5-18 parts of modified powder, and 1-3 parts of catalyst while stirring at 600 rpm, add rubber powder three times, 6-8 parts each time, react for 5-9 hours, heat to 170-190 °C, accelerate stirring to 4000 rpm at a certain speed, continue for 60-80 minutes, then stir at 300 rpm for 2-4 hours, and cool to 20-30 °C to obtain durable recycled rubber asphalt; The frequency of the ultrasound in step (1) is 60-80 kHz; the drop acceleration rate in step (3) is 1 drop / s; the catalyst in step (4) is any one of boron trifluoride, tributyl boron, and titanium tetrachloride; the stirring rate in step (4) is 340 r / min.

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