Preparation method of warm-mixed modified asphalt and preparation method of mixture

Abstract

The invention discloses a preparation method of warm-mixed modified asphalt and a preparation method of a mixture. Preparing LDHs-H2O (layered double hydroxides); heating matrix asphalt to 120-150 DEG C for melting, adding the prepared LDHs-H2O into the molten matrix asphalt according to 4-10% of the mass of the matrix asphalt, and quickly stirring to obtain the warm-mixed modified asphalt. Organic acid radical anions carrying water molecules are intercalated into LDHs layers, a novel anti-aging material LDHs-H2O with ultraviolet shielding and bubble controlled release characteristics is prepared, the controlled release effect of interlayer water molecules and the barrier effect of laminates on oxygen and ultraviolet light are utilized, the thermo-oxidative aging resistance and the ultraviolet aging resistance of asphalt are improved, and the service life of the asphalt is prolonged. Meanwhile, the compatibility of the LDHs and the asphalt is improved by utilizing the organic modification effect of the acid radical anions on the LDHs and the fixing effect of the LDHs laminate on the acid radical anions, and LDHs-H2O comprehensively improves the anti-aging performance of the asphalt and the asphalt mixture from three aspects of reducing the mixing temperature of the asphalt mixture, blocking oxygen from permeating into the asphalt and isolating ultraviolet light.

Description

Technical Field

[0001] This invention relates to the field of road construction materials technology, specifically to a method for preparing warm-mix modified asphalt and a method for preparing the mixture. Background Technology

[0002] Throughout the entire life cycle of asphalt, short-term thermo-oxidative aging encompasses stages such as asphalt production, storage and transportation, and the mixing and compaction of asphalt concrete. The temperature during the mixing stage can reach 170℃, leading to significant volatilization of lightweight components and resulting in the primary thermal damage to asphalt, causing noticeable aging. Long-term thermo-oxidative damage to asphalt is usually accompanied by damage from ultraviolet radiation, primarily occurring during the service life of asphalt pavements, especially in summer when sunlight and ultraviolet radiation are intense. These aging factors ultimately lead to various defects in asphalt roads. To improve the long-term service performance of asphalt pavements, the two major aging problems mentioned above must be addressed first.

[0003] Improving the aging resistance of asphalt has always been a research hotspot both domestically and internationally. Researchers mainly enhance the aging resistance of asphalt by incorporating different types of anti-aging materials, such as antioxidants, layered silicates, inorganic nanoparticles, carbon black, organic UV absorbers, and supramolecular UV blocking materials. However, existing anti-aging technologies are all individual countermeasures targeting either thermo-oxidative aging or UV aging, only improving the asphalt's resistance to either one, and failing to address the simultaneous thermo-oxidative and UV aging problems that occur during the service life of asphalt pavements.

[0004] Warm-mix asphalt technology exhibits significant advantages in resisting thermo-oxidative aging damage. By reducing the mixing temperature of asphalt concrete, it mitigates the volatilization of lightweight components in asphalt under short-term high-energy heat radiation, thereby extending the service life of asphalt concrete products. It also offers technical advantages in suppressing smoke and saving energy and reducing emissions.

[0005] Therefore, it is necessary to design a method for preparing warm-mix modified asphalt. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing warm-mix modified asphalt and a method for preparing the mixture, so as to overcome the shortcomings of the prior art.

[0007] This invention provides a method for preparing warm-mix modified asphalt, comprising the following preparation steps;

[0008] Preparation of LDHs-H2O;

[0009] The base asphalt is heated to 120-150℃ to melt, and the prepared LDHs-H2O is added to the molten base asphalt at 4%-10% of the mass of the base asphalt, and then stirred rapidly to obtain warm-mix modified asphalt.

[0010] The method for preparing warm-mix modified asphalt and the method for preparing the mixture as described above, wherein, preferably, the preparation of LDHs-H2O is carried out by co-precipitation method or calcination reconstruction method, wherein the co-precipitation method includes the following steps:

[0011] Prepare a dilute acid solution and gradually add it to the dried blast furnace slag powder. Stir with a glass rod. When the pH of the solution in the blast furnace slag powder is 1, stop adding the dilute acid solution. Stir magnetically and heat. After reacting for a period of time, stop stirring and heating. After filtration, a light yellow solution and brownish-gray filter residue are obtained.

[0012] Prepare a dilute alkali solution, slowly add the dilute alkali solution dropwise to the pale yellow solution while stirring, adjust the pH to 4, a flocculent precipitate appears, stop stirring, filter to obtain a transparent solution and a brownish-yellow filter residue;

[0013] Magnesium salt and / or aluminum salt are added to the obtained transparent solution to adjust the metal ion concentration ratio so that the concentration ratio of trivalent metal ions to divalent metal ions in the transparent solution is 4:1-1:1; then, sodium hydroxide solution with a molar concentration of 1-4 mol / L is added dropwise to the solution with adjusted metal ion concentration and stirred and heated until pH=10, at which point the addition of sodium hydroxide solution is stopped, and the solution is aged to obtain a supramolecular hydroxide emulsion.

[0014] An intercalating agent was added to the obtained supramolecular hydroxide emulsion, and the mixture was stirred, aged, filtered, and washed to obtain a white precipitate, which was then dried to obtain LDHs-H2O.

[0015] In the warm-mix modified asphalt preparation method and the mixture preparation method described above, preferably, the dilute acid is one of hydrochloric acid, nitric acid, bromic acid, phosphoric acid, carbonic acid and sulfuric acid, and the hydrogen ion concentration in the dilute acid is greater than 0.01 mol / L.

[0016] In the warm-mix modified asphalt preparation method and the mixture preparation method described above, it is preferred that the dilute acid is hydrochloric acid.

[0017] In the warm-mix modified asphalt preparation method and mixture preparation method described above, preferably, the dilute alkali is sodium hydroxide, and the hydroxide ion concentration in the dilute alkali is greater than 0.0001 mol / L.

[0018] In the warm-mix modified asphalt preparation method and mixture preparation method described above, preferably, the anionic intercalating agent is one of sodium dodecylbenzene sulfonate, sodium dodecyl sulfonate, anionic polyacrylamide, and antioxidant.

[0019] In the warm-mix modified asphalt preparation method and the mixture preparation method described above, it is preferred that the concentration ratio of trivalent metal ions to divalent metal ions in the transparent solution is adjusted to 1:2.

[0020] In the warm-mix modified asphalt preparation method and the mixture preparation method described above, preferably, the addition of dilute acid solution is stopped when the pH of the solution in the blast furnace slag powder is 1, the heating temperature is 35℃-60℃, and stirring is stopped after 4.5-6.5 hours and heating is also stopped.

[0021] The warm-mix modified asphalt preparation method and the mixture preparation method described above, wherein, preferably, the calcination and reconstruction method includes the following steps:

[0022] Calcine LDHs at high temperature for 3-6 hours, cool to room temperature, remove, seal and store for later use;

[0023] Prepare an anion solution of acid radicals, add calcined LDHs to the solution, stir, let stand, filter, wash, and dry to obtain LDHs-H2O.

[0024] This invention provides a method for preparing a mixture, comprising the following steps:

[0025] The aggregates are screened and blended according to the gradation design, and then placed in a mixing pot and stirred for 88-95 seconds at a temperature of 130℃-160℃.

[0026] Heat the base asphalt to a molten state, pour it into the mixing pot according to the asphalt-aggregate ratio design, and add 4%-10% of LDHs-H2O powder by weight of asphalt, and stir for 88-95 seconds;

[0027] Add mineral powder and mix for 88-95 seconds, then pour into a mold to form a mixture.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] This invention prepares a novel anti-aging material (supramolecular polymer LDHs-H2O) with both controlled water vapor release and UV shielding properties. Through co-precipitation and structural reconstruction methods, acid anions carrying water molecules are intercalated into the LDH interlayer to form water-rich organic crystals. Utilizing the controlled release of water molecules within the interlayers and the barrier effect of the interlayers against oxygen and UV light, the thermo-oxidative aging and UV aging resistance of asphalt are improved. Simultaneously, the organic modification of LDHs by acid anions and the fixation of acid anions by the LDH interlayers enhance the compatibility between LDHs and asphalt. LDHs-H2O comprehensively improves the anti-aging properties of asphalt and asphalt mixtures by reducing the mixing temperature of asphalt mixtures, blocking oxygen penetration into asphalt, and isolating UV light. The application of LDHs-H2O in asphalt mixtures has significant economic and environmental benefits: it reduces construction temperature, energy consumption, equipment wear and tear, and material costs; it increases the service life of asphalt pavements; it reduces road maintenance and repair costs; it reduces harmful gas emissions; and it improves the construction environment and air quality. Attached Figure Description

[0030] Figure 1 This is the XRD pattern of LDHs-H2O prepared by the coprecipitation method. Detailed Implementation

[0031] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0032] LDHs are layered bimetallic hydroxides. This invention involves intercalating organic acid anions carrying water molecules into the interlayer of LDHs to prepare a novel anti-aging material with both UV shielding and controlled-release bubble properties. Utilizing the controlled-release effect of interlayer water molecules and the barrier effect of the layers against oxygen and UV light, the material enhances the resistance of asphalt to thermo-oxidative aging and UV aging. Simultaneously, the organic modification of LDHs by acid anions and the fixation of acid anions by the LDH layers improve the compatibility between LDHs and asphalt.

[0033] Example 1 of the present invention: The present invention discloses a method for preparing warm-mix modified asphalt, comprising the following preparation steps;

[0034] Preparation of LDHs-H2O; LDHs-H2O refers to "supramolecular polymers".

[0035] The base asphalt is heated to 120-150℃ to melt, and the prepared LDHs-H2O is added to the molten base asphalt at 4%-10% of the mass of the base asphalt, and then stirred rapidly to obtain warm-mix modified asphalt.

[0036] LDHs-H2O can be prepared using either a co-precipitation method or a calcination-reconstruction method. The co-precipitation method uses blast furnace slag as raw material. Blast furnace slag is rich in Ca. 2+ Al 3+ Mg 2+ Besides silicon dioxide and ferrous sulfide, more than 60% of SiO2 can be used to prepare supramolecular hydroxides, which has significant economic benefits and environmental value.

[0037] The coprecipitation method includes the following steps:

[0038] Prepare a dilute acid solution, wherein the dilute acid is one of hydrochloric acid, nitric acid, bromic acid, phosphoric acid, carbonic acid, and sulfuric acid, and the hydrogen ion concentration in the dilute acid is greater than 0.01 mol / L. Hydrochloric acid is preferred. Gradually add the dilute acid solution to the dried blast furnace slag powder, stirring with a glass rod. When the pH of the solution in the blast furnace slag powder reaches 1, stop adding the dilute acid solution. Stir magnetically and heat at 35℃-60℃ for 4.5-6.5 hours, then stop stirring and heating. After filtration, a pale yellow solution and a brownish-gray filter residue are obtained.

[0039] Prepare a dilute alkali solution, wherein the dilute alkali is sodium hydroxide and the hydroxide ion concentration in the dilute alkali is greater than 0.0001 mol / L. Slowly add the dilute alkali solution dropwise to the pale yellow solution while stirring. Adjust the pH to 4. When flocculent precipitate appears, stop stirring. After filtration, a transparent solution and brownish-yellow filter residue are obtained.

[0040] Magnesium salt and / or aluminum salt are added to the obtained transparent solution to adjust the ratio of metal ion concentrations, so that the ratio of trivalent metal ion concentration to divalent metal ion concentration in the transparent solution is 4:1-1:1; then, sodium hydroxide solution with a molar concentration of 1-4 mol / L is added dropwise to the solution with adjusted metal ion concentration, and the mixture is stirred and heated. The heating temperature is set at 75℃-115℃. When the pH is adjusted to 10, the addition of sodium hydroxide solution is stopped, the stirring speed is increased, and stirring is continued for 1.9-2.3 hours. After stirring is stopped, the temperature is kept constant and the mixture is aged for 7.5-10.5 hours to obtain a supramolecular hydroxide emulsion.

[0041] An intercalating agent was added to the obtained supramolecular hydroxide emulsion, and the mixture was stirred, aged, filtered, and washed to obtain a white precipitate, which was then dried to obtain LDHs-H2O. The intercalating agent was one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfonate, anionic polyacrylamide, or an antioxidant.

[0042] Preferably, the ratio of the concentration of trivalent metal ions to the total concentration of divalent metal ions in the transparent solution is adjusted to 1:2.

[0043] The preparation of LDHs-H2O by the calcination reconstruction method includes the following steps:

[0044] Calcine LDHs at high temperature for 3-6 hours, cool to room temperature, remove, seal and store for later use;

[0045] Prepare an anion solution of acid radicals, add calcined LDHs to the solution, stir, let stand, filter, wash, and dry to obtain LDHs-H2O.

[0046] Figure 1 XRD patterns of LDHs and typical intercalator-modified LDHs were compared. The main crystal planes of LDHs include (003), (006), and (009), among which the d-value of the (003) crystal plane is the interlayer spacing of the LDHs. θ The value is 11.62°, and the d value is 7.6094 Å, meaning the interlayer spacing is 0.76 nm. After LDHs are intercalated with the intercalating agent, the 2 of the (003) crystal plane... θ Moving forward to 5.02°, the d value is 17.5888 angstroms, which means the interlayer spacing is 1.76 nm, an increase of 1 nm compared to LDHs.

[0047] Table 1 shows the main performance parameters of LDHs-H2O prepared by the coprecipitation method.

[0048]

[0049] LDHs-H2O was prepared by co-precipitation. The blast furnace slag used was sourced from Xuanhua Iron and Steel Group Co., Ltd., and its chemical composition is shown in the table. The main oxide contents of SiO2, Al2O3, CaO, and MgO were 41.42%, 15.31%, 39.12%, and 9.4%, respectively, making it suitable for the preparation of LDHs-H2O.

[0050] Table 2. Metal Oxide Content in Blast Furnace Slag of Xuan Steel

[0051] metal oxides CaO <![CDATA[SiO2]]> <![CDATA[Al2O3]]> MgO FeO <![CDATA[TiO2]]> MnO content% 39.12 31.42 15.31 9.40 0.58 2.95 0.30

[0052] The finished LDHs were purchased from Beijing Techleil Technology Co., Ltd., and their chemical formula is (Mg 0.667 Al 0.333 (OH)2(CO3) 0.167 (H2O) 0.5 The average particle size is 5 micrometers.

[0053] This invention also discloses a method for preparing a mixture, comprising the following steps:

[0054] The aggregates are screened and blended according to the gradation design, and then placed in a mixing pot and stirred for 88-95 seconds at a temperature of 130℃-160℃.

[0055] Heat the base asphalt to a molten state, pour it into the mixing pot according to the asphalt-aggregate ratio design, and add 4%-10% of LDHs-H2O powder by weight of asphalt, and stir for 88-95 seconds;

[0056] Add mineral powder and mix for 88-95 seconds, then pour into a mold to form the mixture. The amount of mineral powder added should follow the test procedures for asphalt mixtures, generally specifying that mineral powder accounts for 2%-5% of the mass of the asphalt mixture.

[0057] Specific Example 1 of the LDHs-H2O warm mix modified asphalt preparation method:

[0058] To prepare a dilute acid solution, place 115 mL of 35% concentrated hydrochloric acid and 230 mL of distilled water in a beaker and stir magnetically until fully mixed to obtain a diluted hydrochloric acid solution. Let it stand for later use.

[0059] Hydrochloric acid solution was added dropwise to 60g of dried blast furnace slag. The addition was stopped when the pH of the solution reached 1. The temperature was set to 40℃, and the mixture was magnetically stirred for 6 hours before stirring and heating were stopped. The solution was filtered through a clean suction flask to obtain a pale yellow solution and silica residue.

[0060] A 5% sodium hydroxide solution was added dropwise to the above pale yellow solution to adjust the pH to 4. A flocculent precipitate appeared, and after filtration, a transparent chloride solution and a small amount of ferrous hydroxide residue were obtained.

[0061] Add 5% sodium hydroxide dropwise to a pale yellow solution to adjust the pH to 4. A flocculent precipitate appears. After filtration, a transparent chloride solution and a small amount of ferrous hydroxide residue are obtained.

[0062] Add 10g of magnesium chloride nonahydrate to a transparent chloride solution and stir for 2 hours until fully dissolved. Add 2mol / L sodium hydroxide solution dropwise while slowly stirring magnetically, setting the temperature to 80℃. Once the pH is adjusted to 10, stir vigorously for 2 hours, then stop stirring and maintain the temperature for 10 hours to obtain a supramolecular hydroxide emulsion.

[0063] 34.8 g of sodium dodecylbenzenesulfonate was added to a supramolecular hydroxide emulsion and stirred at room temperature for 2 hours to obtain a white precipitate. After filtration, washing and drying, LDHs-H2O was obtained.

[0064] Heat 500 grams of base bitumen to 130°C and maintain the temperature for 60 minutes.

[0065] Add 30 grams of LDHs-H2O to the molten base asphalt and stir rapidly. The base asphalt will produce a large number of bubbles and expand to its maximum volume in about 20 seconds. Then the volume will collapse rapidly. After the volume stabilizes, LDHs-H2O warm mix modified asphalt is obtained.

[0066] Specific Example 2 of LDHs-H2O Warm Mix Modified Asphalt Preparation Method:

[0067] Calcine 50 grams of LDHs at 400℃ for 3 hours, cool to room temperature, seal and store for later use.

[0068] 61 g of anionic polyacrylamide was dissolved in 500 mL of distilled water and stirred at high speed at 50 °C for 2 hours. Calcinated LDHs were added and stirring was continued for 1 hour to obtain a white precipitate. After filtration, washing and drying, LDHs-H2O was obtained.

[0069] Add 20 grams of LDHs-H2O to 330 grams of molten base asphalt and stir rapidly. The volume will first expand and then collapse. Once the volume stabilizes, LDHs-H2O warm-mix modified asphalt is obtained.

[0070] Example 3 of LDHs-H2O warm mix modified asphalt mixture:

[0071] Place 150 mL of 35% HCl concentrated hydrochloric acid and 300 mL of distilled water in a beaker and stir magnetically until fully mixed to obtain a diluted hydrochloric acid solution. Let it stand for later use.

[0072] Hydrochloric acid solution was added dropwise to 75g of dried blast furnace slag. The addition was stopped when the pH of the solution reached 1. The temperature was set to 50℃, and the mixture was magnetically stirred for 5 hours before stirring and heating were stopped. The solution was filtered through a clean suction flask to obtain a pale yellow solution and silica residue.

[0073] Add 8% sodium hydroxide dropwise to a pale yellow solution to adjust the pH to 4. A flocculent precipitate appears. After filtration, a transparent chloride solution and a small amount of ferrous hydroxide residue are obtained.

[0074] Add 11 g of aluminum chloride hexahydrate to a transparent chloride salt solution and stir magnetically for 4 hours at 60°C.

[0075] A 2 mol / L sodium hydroxide solution was added dropwise while the container was placed in an oil bath and stirred at 110°C. After adjusting the pH to 10, the mixture was stirred vigorously for 2 hours, then stirring was stopped, and the temperature was maintained for 8 hours to obtain the supramolecular hydroxide.

[0076] 50 g of sodium dodecylbenzenesulfonate was added to supramolecular hydroxide and stirred at room temperature for 1 hour to obtain a white precipitate. The precipitate was filtered, washed and dried to obtain LDHs-H2O.

[0077] According to the gradation design of the "Technical Specification for Construction of Asphalt Pavement of Highway" (JTG F40-2004), 6 kg of basalt aggregate of each particle size is weighed, the asphalt-aggregate ratio is 4.8%, and the mineral powder accounts for 3% of the mass of asphalt and aggregate.

[0078] Add the prepared basalt aggregate to the mixing pot, heat to 140℃, and premix for 90 seconds;

[0079] Heat 70# base asphalt to 140℃, add 288g of 70# base asphalt according to the asphalt-aggregate ratio design, and add 23g of LDHs-H2O powder at 8% of the asphalt mass, then mix for 90s.

[0080] Add 189 grams of mineral powder, mix for 90 seconds, and mold to obtain LDHs-H2O warm-mix modified asphalt mixture.

[0081] This invention prepares a novel anti-aging material (supramolecular polymer LDHs-H2O) with both controlled water vapor release and UV shielding properties. Through co-precipitation and structural reconstruction methods, acid anions carrying water molecules are intercalated into the LDHs interlayer to form water-rich organic crystals. LDHs-H2O comprehensively improves the anti-aging properties of asphalt and asphalt mixtures from three aspects: reducing the mixing temperature of asphalt mixtures, blocking oxygen penetration into asphalt, and isolating ultraviolet light. The application of LDHs-H2O in asphalt mixtures has significant economic and environmental benefits: reducing construction temperature, decreasing energy consumption, equipment wear and tear, and material costs; increasing the service life of asphalt pavements; reducing road maintenance and repair costs; reducing harmful gas emissions; and improving the construction environment and air quality.

[0082] The LDHs-based controlled-release bubble-type warm-mix asphalt preparation process utilizes the controlled-release characteristics of the LDHs layered structure. Through structural design, water vapor is stably released to form bubbles, thus achieving the warm-mix effect. Simultaneously, the UV-shielding properties of LDHs enhance the asphalt's anti-aging properties, overcoming the shortcomings of existing technologies. This process has significant theoretical and practical implications for improving the warm-mix asphalt technology system and promoting the development of road engineering materials.

[0083] The basic principles of the present invention have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in the present invention are merely examples and not limitations, and should not be considered as essential features of each embodiment of the present invention. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the present invention to the necessity of employing the aforementioned specific details.

[0084] The block diagrams of devices, apparatuses, devices, and systems involved in this invention are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0085] Additionally, as used herein, the “or” used in a list of items beginning with “at least one” indicates a separate list, such that a list of, for example, “at least one of A, B, or C” means A or B or C, or AB or AC or BC, or ABC (i.e., A and B and C). Furthermore, the word “exemplary” does not imply that the described example is preferred or better than other examples.

[0086] It should also be noted that in the system and method of the present invention, the components or steps can be decomposed and / or recombined. These decompositions and / or recombinations should be considered as equivalent solutions of the present invention.

[0087] Various changes, substitutions, and modifications can be made to the technology described herein without departing from the teachings defined by the appended claims. Furthermore, the scope of the claims is not limited to the specific aspects of the processes, machines, manufacturing processes, events, means, methods, and actions described above. Currently existing or later-developed processes, machines, manufacturing processes, events, means, methods, or actions that perform substantially the same function or achieve substantially the same result as the corresponding aspects described herein can be utilized. Therefore, the appended claims include such processes, machines, manufacturing processes, events, means, methods, or actions within their scope.

[0088] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the invention. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the invention. Therefore, the invention is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0089] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the invention to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

Claims

1. A method for preparing warm-mix modified asphalt, characterized in that: The preparation steps include the following; Preparation of LDHs-H2O; The base asphalt is heated to 120-150℃ to melt, and the prepared LDHs-H2O is added to the molten base asphalt at 4%-10% of the mass of the base asphalt, and then stirred rapidly to obtain warm-mix modified asphalt.

2. The method for preparing warm-mix modified asphalt according to claim 1, characterized in that: LDHs-H2O can be prepared by co-precipitation or calcination reconstruction. The co-precipitation method includes the following steps: Prepare a dilute acid solution and gradually add it to the dried blast furnace slag powder. Stir with a glass rod. When the pH of the solution in the blast furnace slag powder is 1, stop adding the dilute acid solution. Stir magnetically and heat. After reacting for a period of time, stop stirring and heating. After filtration, a light yellow solution and brownish-gray filter residue are obtained. Prepare a dilute alkali solution, slowly add the dilute alkali solution dropwise to the pale yellow solution while stirring, adjust the pH to 4, a flocculent precipitate appears, stop stirring, filter to obtain a transparent solution and a brownish-yellow filter residue; Magnesium salt and / or aluminum salt are added to the obtained transparent solution to adjust the metal ion concentration ratio so that the concentration ratio of trivalent metal ions to divalent metal ions in the transparent solution is 4:1-1:1; then, sodium hydroxide solution with a molar concentration of 1-4 mol / L is added dropwise to the solution with adjusted metal ion concentration and stirred and heated until pH=10, at which point the addition of sodium hydroxide solution is stopped, and the solution is aged to obtain a supramolecular hydroxide emulsion. An intercalating agent was added to the obtained supramolecular hydroxide emulsion, and the mixture was stirred, aged, filtered, and washed to obtain a white precipitate, which was then dried to obtain LDHs-H2O.

3. The method for preparing warm-mix modified asphalt according to claim 2, characterized in that: The dilute acid is one of hydrochloric acid, nitric acid, bromic acid, phosphoric acid, carbonic acid, and sulfuric acid, and the hydrogen ion concentration in the dilute acid is greater than 0.01 mol / L.

4. The method for preparing warm-mix modified asphalt according to claim 3, characterized in that: The dilute acid is preferably hydrochloric acid.

5. The method for preparing warm-mix modified asphalt according to claim 2, characterized in that: The dilute alkali is sodium hydroxide, and the concentration of hydroxide ions in the dilute alkali is greater than 0.0001 mol / L.

6. The method for preparing warm-mix modified asphalt according to claim 2, characterized in that: The anionic intercalating agent is one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfonate, anionic polyacrylamide, and antioxidant.

7. The method for preparing warm-mix modified asphalt according to claim 2, characterized in that: Adjust the ratio of trivalent metal ion concentration to divalent metal ion concentration in the transparent solution to 1:

2.

8. The method for preparing warm-mix modified asphalt according to claim 2, characterized in that: When the pH of the solution in the blast furnace slag powder is 1, stop adding dilute acid solution. The heating temperature is 35℃-60℃. After stirring for 4.5-6.5 hours, stop stirring and stop heating.

9. The method for preparing warm-mix modified asphalt according to claim 2, characterized in that: The calcination reconstruction method includes the following steps: Calcine LDHs at high temperature for 3-6 hours, cool to room temperature, remove, seal and store for later use; Prepare an anion solution of acid radicals, add calcined LDHs to the solution, stir, let stand, filter, wash, and dry to obtain LDHs-H2O.

10. A method for preparing a mixture, characterized in that: Includes the following steps: The aggregates are screened and blended according to the gradation design, and then placed in a mixing pot and stirred for 88-95 seconds at a temperature of 130℃-160℃. Heat the base asphalt to a molten state, pour it into the mixing pot according to the asphalt-aggregate ratio design, and add 4%-10% of LDHs-H2O powder by weight of asphalt, and stir for 88-95 seconds; Add mineral powder and mix for 88-95 seconds, then pour into a mold to form a mixture.

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