Asphalt anti-stripping agent and preparation method thereof

Abstract

The invention discloses an asphalt anti-stripping agent and a preparation method thereof, and the anti-stripping agent is prepared from the following components in parts by weight: 80 to 90 parts of core-shell polymer emulsion, 1 to 3 parts of siloxane modified nano calcium silicate hydrate gel, 5 to 8 parts of bio-based elastomer / hindered phenol modified bio-based elastomer, 0.5 to 1.5 parts of surfactant and 0.1 to 0.3 part of quaternary ammonium salt. The siloxane-modified nano calcium silicate hydrate gel can be chemically bonded with the core-shell structure polymer emulsion and the bio-based elastomer respectively, so that a three-layer gradient composite structure comprising the core-shell structure polymer emulsion, the siloxane-modified nano calcium silicate hydrate gel and the bio-based elastomer from inside to outside is formed; the gradient composite structure has a larger specific surface area, enhances interface contact and interaction with asphalt, remarkably improves the anti-stripping performance of the asphalt, and enables the asphalt to still keep excellent durability and stability in a complex environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of petrochemical engineering, and particularly relates to an asphalt anti-stripping agent and a preparation method thereof. Background Art

[0002] Asphalt concrete, as an important building material, is widely used in the anti-seepage and protection of structures such as dam panels, spillways, and channels. However, due to the special environment of water conservancy and hydropower projects, such as long-term immersion, wet-dry alternation, and water flow scouring, asphalt concrete faces serious problems of stripping and durability.

[0003] The prior art usually adopts the method of adding an anti-stripping agent. The anti-stripping agent can enhance the physical-chemical bonding effect between asphalt concrete and aggregates, and improve the adhesion between asphalt concrete and aggregates.

[0004] However, although traditional anti-stripping agents can improve adhesion to a certain extent, in the long-term working environment, the adhesion effect gradually weakens, and they cannot maintain good bonding between asphalt and aggregates for a long time, which affects the durability and overall performance of asphalt concrete. Summary of the Invention

[0005] To solve the above problems, the present invention discloses an asphalt anti-stripping agent and a preparation method thereof.

[0006] The present invention discloses an asphalt anti-stripping agent, which, by weight, comprises: 80 parts - 90 parts of core-shell polymer emulsion, 1 part - 3 parts of silicone-modified nano-hydrated calcium silicate gel, 5 parts - 8 parts of bio-based elastomer / hindered phenol-modified bio-based elastomer, 0.5 part - 1.5 parts of surfactant, and 0.1 part - 0.3 part of quaternary ammonium salt.

[0007] The core-shell polymer emulsion is an acrylate-silicone polymer emulsion;

[0008] The core layer monomer of the core-shell polymer emulsion is acrylate, and the shell layer monomer of the core-shell polymer emulsion is silicone.

[0009] The glass transition temperature of the core layer monomer is 15°C - 20°C;

[0010] The glass transition temperature of the shell layer monomer is -55°C - -65°C.

[0011] The silicone-modified nano-hydrated calcium silicate gel is γ-aminopropyltrimethoxysilane-modified nano-hydrated calcium silicate gel.

[0012] The present invention also discloses a preparation method of an asphalt anti-stripping agent, which comprises the following steps:

[0013] Prepare 80 to 90 parts of core-shell polymer emulsion using 56 to 63 parts of core layer monomer and 24 to 27 parts of shell layer monomer by weight;

[0014] After heating 80 to 90 parts of core-shell polymer emulsion by weight to the first preset temperature, add 1 to 3 parts of silicone-modified nano-hydrated calcium silicate gel, 5 to 8 parts of bio-based elastomer / hindered phenol modified bio-based elastomer, 0.5 to 1.5 parts of surfactant, and 0.1 to 0.3 parts of quaternary ammonium salt to the core-shell polymer emulsion in sequence, and stir for the first preset time at a preset speed to obtain an asphalt anti-stripping agent.

[0015] The preparation method of the core-shell polymer emulsion is specifically as follows:

[0016] Uniformly mix 160 to 200 parts of deionized water, 0.15 to 0.3 parts of emulsifier, and 0.05 to 0.15 parts of initiator by weight and heat to the second preset temperature to obtain a first mixed solution;

[0017] Dropwise add 56 to 63 parts of core layer monomer by weight to the first mixed solution at a constant temperature for the second preset time, and then carry out a constant temperature reaction for the third preset time to obtain a core layer emulsion;

[0018] Mix 24 to 27 parts of shell layer monomer and 0.35 to 0.7 parts of emulsifier by weight evenly to obtain a second mixed solution;

[0019] Dropwise add the second mixed solution to the core layer emulsion at a constant temperature for the fourth preset time, and then carry out a constant temperature reaction for the fifth preset time to obtain 80 to 90 parts of core-shell polymer emulsion.

[0020] The preparation method of the silicone-modified nano-hydrated calcium silicate gel is specifically as follows:

[0021] Disperse 1 to 3 parts of nano-hydrated calcium silicate gel by weight in an ethanol solution, and perform ultrasonic treatment for the sixth preset time to obtain a dispersion; the volume of the ethanol solution is 5 to 10 times the mass of the nano-hydrated calcium silicate gel;

[0022] Add γ-aminopropyltrimethoxysilane to the dispersion, and carry out a reflux reaction at the third preset temperature for 2 to 3 hours to obtain a third mixed solution; the addition amount of γ-aminopropyltrimethoxysilane is 3% to 5% of the mass of the nano-hydrated calcium silicate gel;

[0023] Carry out centrifugation, washing, and drying treatments on the third mixed solution respectively to obtain silicone-modified nano-hydrated calcium silicate gel.

[0024] The preparation method of the hindered phenol modified bio-based elastomer is specifically as follows:

[0025] Heat a bio - based elastomer weighing 5 parts - 8 parts by weight to a fourth preset temperature to obtain the melted bio - based elastomer;

[0026] Add a hindered phenol antioxidant to the melted bio - based elastomer and stir evenly to obtain a hindered phenol - modified bio - based elastomer;

[0027] The dosage of the hindered phenol antioxidant is 0.1% - 0.5% of the mass of the bio - based elastomer.

[0028] The first preset temperature is 40°C - 50°C, the second preset temperature is 70°C - 80°C, the third preset temperature is 60°C - 70°C, and the fourth preset temperature is 60°C - 70°C;

[0029] The first preset time is 30 min - 60 min, the second preset time is 1 h - 1.5 h, the third preset time is 1 h - 1.5 h, the fourth preset time is 1 h - 2 h, the fifth preset time is 2 h - 3 h, and the sixth preset time is 30 min - 60 min;

[0030] The preset speed is 500 rpm - 1000 rpm.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The surface of the nano - hydrated calcium silicate gel modified by siloxane in the present invention has active groups, which can respectively form chemical bonds with the core - shell structure polymer emulsion and the bio - based elastomer, forming a three - layer gradient composite structure from the inside to the outside including the core - shell polymer emulsion, the siloxane - modified nano - hydrated calcium silicate gel, and the bio - based elastomer. This gradient composite structure has a larger specific surface area, enhances the interfacial contact and interaction with asphalt, significantly improves the anti - stripping performance of asphalt, and enables it to maintain excellent durability and stability in complex environments;

[0033] (2) After being modified by silane, the dispersibility of the nano - hydrated calcium silicate gel in the present invention is significantly improved, forming a reinforcing network of 50 - 200 nm, increasing the specific surface area of the material, and further enhancing the interfacial bonding force; the bio - based elastomer forms an interpenetrating polymer network structure through in - situ grafting, improving the low - temperature crack resistance of the material. The three components of this gradient composite structure form a tight synergistic effect through chemical bonding and physical entanglement, significantly improving the interfacial bonding force and stress transfer efficiency, enabling a continuous stress transfer path to be formed between the layers, and significantly improving the overall performance of the asphalt concrete;

[0034] (3) In the present invention, the outer bio-based elastomer has flexibility and crack resistance, the middle nano-hydrated calcium silicate gel has strong mechanical properties and waterproofness, and the inner acrylate-siloxane polymer emulsion can improve the adhesion and weather resistance of asphalt concrete, thereby forming a multi-layer protection for asphalt concrete and significantly improving the anti-stripping performance of asphalt concrete;

[0035] (4) The glass transition temperatures of the core layer and the shell layer of the core-shell polymer emulsion of the present invention are different. Among them, the acrylate core emulsion (glass transition temperature 15-20 °C) has high hardness and can provide high-temperature anti-deformation ability. The siloxane shell emulsion (glass transition temperature -55--65 °C) has low-temperature flexibility. The bio-based elastomer (glass transition temperature -40 °C) grafted with the core-shell emulsion can form an interpenetrating crosslinked IPN network structure, forming a gradient matching relationship of shear modulus, which can effectively disperse temperature stress, thereby improving the high-temperature stability and low-temperature crack resistance of the asphalt anti-stripping agent;

[0036] (5) In the preparation method of the present invention, the prepared core-shell polymer emulsion is heated to a first preset temperature, and then the siloxane-modified nano-hydrated calcium silicate gel and the hindered phenol-modified bio-based elastomer are added in sequence; heating enhances the fluidity of the core-shell polymer emulsion, facilitating the uniform dispersion of subsequent components, and an appropriate temperature helps the subsequent interfacial reaction to proceed. The modified nano-hydrated calcium silicate gel chemically bonds with the core-shell structure polymer emulsion and the bio-based elastomer respectively; and the molten bio-based elastomer can better mix with other components and form a stable interface through physical entanglement and chemical bonding. Therefore, the preparation method of the present invention realizes the close synergistic effect among various components through hierarchical grafting and interface optimization, thereby effectively dispersing stress, inhibiting crack propagation, and enhancing the adaptability to environmental changes, thus comprehensively improving the durability and anti-stripping property of asphalt;

[0037] (6) The present invention uses bio-based elastomer and siloxane-modified nano-hydrated calcium silicate gel, which have lower synthesis costs than traditional materials and a high proportion of bio-based components, significantly reducing manufacturing carbon emissions; and the design of the gradient composite structure optimizes the material usage efficiency while improving performance, achieving a breakthrough balance between cost and performance;

[0038] (7) In the present invention, on the one hand, γ-aminopropyltrimethoxysilane-modified nano-hydrated calcium silicate gel can form a hydrogen bond network with the hydroxyl groups on the surface of the aggregate, reduce the porosity at the asphalt-aggregate interface, and enhance the interfacial bonding force, thereby significantly improving the anti-stripping performance; on the other hand, the dispersibility of the modified nano-hydrated calcium silicate gel is significantly improved, forming a reinforcing network with a size of 50-200 nm, further enhancing the mechanical strength of the asphalt. In addition, the bio-based elastomer is in-situ grafted onto the γ-aminopropyltrimethoxysilane-modified nano-hydrated calcium silicate gel to form an interpenetrating polymer network structure, significantly improving the low-temperature crack resistance of the asphalt;

[0039] (8) In the present invention, the hindered phenol-modified bio-based elastomer can effectively inhibit the oxidation reaction and delay the aging of the asphalt, thereby improving the freeze-thaw cycle resistance of the asphalt. Description of the Drawings

[0040] Figure 1 is a comparative infrared absorption spectrum diagram of the gradient composite structure of Example 1 of the present invention and Comparative Example 1 and Comparative Example 2;

[0041] Figure 2 is a SEM diagram of the appearance morphology of the core-shell structure of the anti-stripping agent of the present invention, with a scale of 50 μm;

[0042] Figure 3 is a SEM diagram of the microscopic morphology of the interpenetrating network formed after the surface of the anti-stripping agent of the present invention is grafted and modified with nano-hydrated calcium silicate gel and bio-based elastomer, with a scale of 1 μm. Detailed Embodiments

[0043] In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present invention. However, those skilled in the art should clearly understand that the present invention can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present invention.

[0044] The present invention discloses an asphalt anti-stripping agent. The anti-stripping agent, by weight, comprises: 80-90 parts of core-shell polymer emulsion, 1-3 parts of siloxane-modified nano-hydrated calcium silicate gel, 5-8 parts of bio-based elastomer / hindered phenol-modified bio-based elastomer, 0.5-1.5 parts of surfactant, and 0.1-0.3 parts of quaternary ammonium salt.

[0045] In the present invention, the nano-hydrated calcium silicate gel modified by siloxane can form chemical bonds with the core-shell structure polymer emulsion and the bio-based elastomer respectively, forming a three-layer gradient composite structure from the inside to the outside, including the core-shell polymer emulsion, siloxane-modified nano-hydrated calcium silicate gel, and bio-based elastomer (asFigure 1 As shown in the figure, this gradient composite structure has a larger specific surface area, enhances the interfacial contact and interaction with asphalt, significantly improves the anti-stripping performance of asphalt, and enables it to maintain excellent durability and stability in complex environments.

[0046] In the present invention, in addition to binding with the silicone-modified nano-hydrated calcium silicate gel, the bio-based elastomer can also bind with the core-shell structured polymer emulsion. This multiple binding method enables the anti-stripping agent of the present invention to form a tight gradient composite structure, further strengthening the performance of the anti-stripping agent, and enabling the asphalt anti-stripping agent of the present invention to significantly improve the anti-stripping property, freeze-thaw cycle resistance, low-temperature crack resistance and mechanical strength of asphalt.

[0047] The core-shell polymer emulsion is an acrylate-silicone polymer emulsion;

[0048] The core layer monomer of the core-shell polymer emulsion is acrylate, and the shell layer monomer of the core-shell polymer emulsion is silicone.

[0049] The glass transition temperature of the core layer monomer is 15°C - 20°C;

[0050] The glass transition temperature of the shell layer monomer is -55°C - -65°C.

[0051] The silicone-modified nano-hydrated calcium silicate gel is a γ-aminopropyltrimethoxysilane-modified nano-hydrated calcium silicate gel, with a particle size of 50 - 200 nm and a grafting rate ≥ 30%.

[0052] The bio-based elastomer is a polylactic acid-polycaprolactone copolymer, with an average molecular weight of 30000 - 50000 and a glass transition temperature of -40°C.

[0053] As Figure 3 shown, the bio-based elastomer of the present invention in-situ grafts on the γ-aminopropyltrimethoxysilane-modified nano-hydrated calcium silicate gel to form an interpenetrating polymer network structure, significantly improving the low-temperature crack resistance of asphalt.

[0054] The present invention also discloses a method for preparing an asphalt anti-stripping agent, comprising the following steps:

[0055] Using 56 parts - 63 parts by weight of the core layer monomer and 24 parts - 27 parts by weight of the shell layer monomer to prepare 80 parts - 90 parts of the core-shell polymer emulsion;

[0056] The preparation method of the core-shell polymer emulsion is specifically as follows:

[0057] Mix 160 to 200 parts by weight of deionized water, 0.15 to 0.3 parts of an emulsifier, and 0.05 to 0.15 parts of an initiator uniformly and heat to a second preset temperature to obtain a first mixed solution; the initiator is potassium persulfate, and the emulsifier is sodium dodecylbenzenesulfonate;

[0058] Dropwise add 56 to 63 parts by weight of the core layer monomer to the first mixed solution at a constant temperature according to a second preset time, and then carry out a reaction at a constant temperature for a third preset time to obtain a core layer emulsion;

[0059] Mix 24 to 27 parts by weight of the shell layer monomer and 0.35 to 0.7 parts of an emulsifier uniformly to obtain a second mixed solution, wherein the emulsifier is sodium dodecyl sulfate;

[0060] Dropwise add the second mixed solution to the core layer emulsion at a constant temperature within a fourth preset time, and then carry out a reaction at a constant temperature for a fifth preset time to obtain 80 to 90 parts of a core-shell polymer emulsion.

[0061] Heat 80 to 90 parts by weight of the core-shell polymer emulsion to a first preset temperature, and then successively add 1 to 3 parts by weight of a silicone-modified nano hydrated calcium silicate gel, 5 to 8 parts of a bio-based elastomer / hindered phenol-modified bio-based elastomer, 0.5 to 1.5 parts of a surfactant, and 0.1 to 0.3 parts of a quaternary ammonium salt thereto, and stir at a preset speed for a first preset time to obtain an asphalt anti-stripping agent.

[0062] The preparation method of the silicone-modified nano hydrated calcium silicate gel is as follows:

[0063] Disperse 1 to 3 parts by weight of the nano hydrated calcium silicate gel in an ethanol solution, and perform ultrasonic treatment for a sixth preset time to obtain a dispersion; the volume of the ethanol solution is 5 to 10 times the mass of the nano hydrated calcium silicate gel;

[0064] Add γ-aminopropyltrimethoxysilane to the dispersion, and carry out a reflux reaction at a third preset temperature for 2 to 3 hours to obtain a third mixed solution; the addition amount of γ-aminopropyltrimethoxysilane is 3% to 5% of the mass of the nano hydrated calcium silicate gel;

[0065] Carry out centrifugation, washing, and drying treatments on the third mixed solution respectively to obtain the silicone-modified nano hydrated calcium silicate gel.

[0066] The preparation method of the hindered phenol-modified bio-based elastomer is as follows:

[0067] Heat 5 to 8 parts by weight of the bio-based elastomer to a fourth preset temperature to obtain a molten bio-based elastomer;

[0068] Add a hindered phenol antioxidant to the molten bio-based elastomer and stir evenly to obtain a hindered phenol-modified bio-based elastomer;

[0069] The dosage of the hindered phenol antioxidant is 0.1%-0.5% of the mass of the bio-based elastomer.

[0070] The first preset temperature is 40°C - 50°C, the second preset temperature is 70°C - 80°C, the third preset temperature is 60°C - 70°C, and the fourth preset temperature is 60°C - 70°C;

[0071] The first preset time is 30 min - 60 min, the second preset time is 1 h - 1.5 h, the third preset time is 1 h - 1.5 h, the fourth preset time is 1 h - 2 h, the fifth preset time is 2 h - 3 h, and the sixth preset time is 30 min - 60 min;

[0072] The preset speed is 500 rpm - 1000 rpm.

[0073] The dosage of the anti-stripping agent of the present invention is 0.3%-0.8% of the weight of the asphalt.

[0074] The present invention will be described in detail below with reference to examples and comparative examples.

[0075] Example 1

[0076] The present invention discloses an asphalt anti-stripping agent, which includes by weight: 80 parts of acrylate-siloxane polymer emulsion, 1 part of γ-aminopropyltrimethoxysilane-modified nano-hydrated calcium silicate gel, 5 parts of hindered phenol-modified bio-based elastomer, 1.5 parts of sulfobetaine surfactant, and 0.1 part of chitosan quaternary ammonium salt.

[0077] The acrylate-siloxane polymer emulsion has a core-shell structure and a glass transition temperature of 15°C.

[0078] The particle size of the γ-aminopropyltrimethoxysilane-modified nano-hydrated calcium silicate gel is 200 nm, and the grafting rate ≥ 30%.

[0079] The bio-based elastomer is a polylactic acid-polycaprolactone copolymer with an average molecular weight of 50,000 and a melting point of 55°C.

[0080] The preparation method of the asphalt anti-stripping agent includes the following steps:

[0081] Add 160 parts by weight of deionized water to the reaction kettle, then successively add 0.15 parts by weight of emulsifier and 0.05 - 0.15 parts by weight of initiator. After stirring evenly and heating to 70 °C, dropwise add 56 parts by weight of acrylate monomer. Control the dropping time within 1 hour. After the dropping is completed, keep the reaction at a constant temperature for 1 hour to form the core layer emulsion; among them, the initiator is potassium persulfate, and the emulsifier is sodium dodecylbenzenesulfonate;

[0082] Mix 24 parts by weight of siloxane monomer with 0.35 parts by weight of emulsifier evenly. After the reaction of the core layer emulsion is completed, slowly drop the mixture into the core layer emulsion. Control the dropping time within 1 hour. Keep the reaction temperature at 70 °C during the dropping process. After the dropping is completed, continue to keep the reaction at a constant temperature for 2 hours to polymerize the siloxane monomer on the surface of the core layer to form a shell layer, and obtain an acrylate - siloxane polymer emulsion with a core - shell structure; among them, the emulsifier is sodium dodecyl sulfate;

[0083] Disperse nano - hydrated calcium silicate gel in an ethanol solution. The volume of the ethanol solution is 5 times the mass of the nano - hydrated calcium silicate gel. Perform ultrasonic treatment for 30 minutes to form a uniform dispersion; add γ - aminopropyltrimethoxysilane to the dispersion. The addition amount of γ - aminopropyltrimethoxysilane is 3% of the mass of the nano - hydrated calcium silicate gel. Carry out reflux reaction at 60 °C for 2 hours, and then successively carry out centrifugation, washing, and drying to obtain γ - aminopropyltrimethoxysilane - modified nano - hydrated calcium silicate gel;

[0084] Heat the bio - based elastomer to 60 °C to make it melt, then add an appropriate amount of antioxidant and stir evenly. The antioxidant is a hindered phenol antioxidant, and the dosage of the antioxidant is 0.1% of the mass of the bio - based elastomer to obtain a hindered phenol - modified bio - based elastomer;

[0085] Heat the acrylate - siloxane polymer emulsion with a core - shell structure to 40 °C, and successively add the γ - aminopropyltrimethoxysilane - modified nano - hydrated calcium silicate gel, hindered phenol - modified bio - based elastomer, surfactant, and chitosan quaternary ammonium salt obtained in step. The stirring speed is 500 rpm, and the stirring time is 30 minutes to obtain an asphalt anti - stripping agent.

[0086] The usage method of the asphalt anti - stripping agent in this example is to add the asphalt anti - stripping agent to the heated asphalt at 0.3% of the mass of the asphalt, stir evenly, and then mix the asphalt added with the anti - stripping agent with the aggregate to obtain an asphalt mixture.

[0087] After doping the anti - stripping agent in this example, the performance test results of the asphalt concrete are shown in Table 1.

[0088] Example 2

[0089] The difference from Example 1 is that it includes: 85 parts of acrylate - siloxane polymer emulsion by weight.

[0090] After doping the anti-stripping agent in this embodiment, the performance test results of the asphalt concrete are shown in Table 1.

[0091] Example 3

[0092] The difference from Example 1 is that it includes 90 parts by weight of acrylate-siloxane polymer emulsion.

[0093] After doping the anti-stripping agent in this embodiment, the performance test results of the asphalt concrete are shown in Table 1.

[0094] Example 4

[0095] The difference from Example 1 is that it includes 2 parts by weight of γ-aminopropyltrimethoxysilane modified nano-hydrated calcium silicate gel.

[0096] After doping the anti-stripping agent in this embodiment, the performance test results of the asphalt concrete are shown in Table 1.

[0097] Example 5

[0098] The difference from Example 1 is that it includes 3 parts by weight of γ-aminopropyltrimethoxysilane modified nano-hydrated calcium silicate gel.

[0099] After doping the anti-stripping agent in this embodiment, the performance test results of the asphalt concrete are shown in Table 1.

[0100] Example 6

[0101] The difference from Example 1 is that it includes 7 parts by weight of hindered phenol modified bio-based elastomer.

[0102] After doping the anti-stripping agent in this embodiment, the performance test results of the asphalt concrete are shown in Table 1.

[0103] Example 7

[0104] The difference from Example 1 is that it includes 8 parts by weight of hindered phenol modified bio-based elastomer.

[0105] After doping the anti-stripping agent in this embodiment, the performance test results of the asphalt concrete are shown in Table 1.

[0106] Example 8

[0107] The difference from Example 1 is that the dosage of the anti-stripping agent is 0.5% of the weight of the asphalt.

[0108] After doping the anti-stripping agent in this embodiment, the performance test results of the asphalt concrete are shown in Table 1.

[0109] Example 9

[0110] The difference from Example 1 is that the dosage of the anti-stripping agent is 0.8% of the weight of the asphalt.

[0111] After doping the anti-stripping agent in this example, the performance test results of the asphalt concrete are shown in Table 1.

[0112] Comparative Example 1

[0113] The difference from Example 1 is that 5 parts of bio-based elastomer are used to replace the original 5 parts of hindered phenol-modified bio-based elastomer.

[0114] After doping the anti-stripping agent in this comparative example, the performance test results of the asphalt concrete are shown in Table 1.

[0115] Comparative Example 2

[0116] The difference from Example 1 is that it includes 1 part of nano-hydrated calcium silicate gel by weight.

[0117] After doping the anti-stripping agent in this comparative example, the performance test results of the asphalt concrete are shown in Table 1.

[0118] Comparative Example 3

[0119] The difference from Example 1 is that in the process of preparing the core-shell structured acrylate-siloxane polymer emulsion, by weight, the acrylate monomer is 55 parts and the siloxane monomer is 24 parts.

[0120] After doping the anti-stripping agent in this comparative example, the performance test results of the asphalt concrete are shown in Table 1.

[0121] Comparative Example 4

[0122] The difference from Example 1 is that in the process of preparing the core-shell structured acrylate-siloxane polymer emulsion, by weight, the acrylate monomer is 65 parts and the siloxane monomer is 24 parts.

[0123] After doping the anti-stripping agent in this comparative example, the performance test results of the asphalt concrete are shown in Table 1.

[0124] Comparative Example 5

[0125] The difference from Example 1 is that in the process of preparing the core-shell structured acrylate-siloxane polymer emulsion, by weight, the acrylate monomer is 56 parts and the siloxane monomer is 23 parts.

[0126] After doping the anti-stripping agent in this comparative example, the performance test results of the asphalt concrete are shown in Table 1.

[0127] Comparative Example 6

[0128] The difference from Example 1 is that in the process of preparing the core-shell structured acrylate-siloxane polymer emulsion, by weight, the acrylate monomer is 56 parts and the siloxane monomer is 28 parts.

[0129] After doping the anti-stripping agent in this comparative example, the performance test results of the asphalt concrete are shown in Table 1.

[0130] Table 1 Test results of asphalt anti-stripping performance

[0131]

[0132]

[0133] It can be seen from Table 1 that the following conclusions can be drawn:

[0134] It can be seen from Examples 1-3 that as the content of the polymer emulsion in the anti-stripping agent increases, the anti-stripping property and high- and low-temperature stability of the asphalt gradually increase; it can be seen from Examples 1, 4, and 5 that as the content of the siloxane-modified nano-hydrated calcium silicate gel increases, the anti-stripping property and high- and low-temperature stability of the asphalt gradually increase; it can be seen from Examples 1, 6, and 7 that as the content of the hindered phenol-modified bio-based elastomer increases, the anti-stripping property and high- and low-temperature stability of the asphalt gradually increase; it can be seen from Examples 1, 8, and 9 that as the dosage of the anti-stripping agent increases, the anti-stripping property and high- and low-temperature stability of the asphalt gradually increase; it can be seen from Example 1 and Comparative Example 1 that compared with the bio-based elastomer, using the anti-stripping agent added with the hindered phenol-modified bio-based elastomer has a more obvious improvement effect on the anti-freeze-thaw cycle performance of the asphalt; it can be seen from Example 1 and Comparative Example 2 that the anti-stripping agent added with the siloxane-modified nano-hydrated calcium silicate gel has a more significant improvement effect on the anti-stripping property and high- and low-temperature stability of the asphalt than the anti-stripping agent added with the nano-hydrated calcium silicate gel. Combining Figure 1 and Figure 2 it can be known that this is because the anti-stripping agent added with the siloxane-modified nano-hydrated calcium silicate gel has a three-layer composite gradient structure; it can be seen from Example 1 and Comparative Examples 4-6 that the core-shell structure with the glass transition temperature of the present invention cannot be prepared with the core layer monomer or shell layer monomer exceeding the preset range. Therefore, the high- and low-temperature stability and anti-stripping performance of the asphalt added with Comparative Examples 4-6 are poor.

[0135] Compared with the prior art, the present invention has the following beneficial effects:

[0136] (1) The surface of the nano-hydrated calcium silicate gel modified by siloxane in the present invention has active groups, which can respectively form chemical bonds with the core-shell structure polymer emulsion and the bio-based elastomer, forming a three-layer gradient composite structure from the inside out, including the core-shell polymer emulsion, the siloxane-modified nano-hydrated calcium silicate gel, and the bio-based elastomer. This gradient composite structure has a larger specific surface area, enhances the interfacial contact and interaction with asphalt, significantly improves the anti-stripping performance of asphalt, and enables it to maintain excellent durability and stability in complex environments;

[0137] (2) After being modified by silane, the dispersibility of the nano-hydrated calcium silicate gel in the present invention is significantly improved, forming a reinforcing network with a size of 50-200 nm, increasing the specific surface area of the material, and further enhancing the interfacial bonding force; the bio-based elastomer forms an interpenetrating polymer network structure through in-situ grafting, improving the low-temperature crack resistance of the material. The three components of this gradient composite structure form a close synergistic effect through chemical bonding and physical entanglement, significantly improving the interfacial bonding force and stress transfer efficiency, forming a continuous stress transfer path between the layers, and significantly improving the overall performance of asphalt concrete;

[0138] (3) In the present invention, the outer bio-based elastomer has flexibility and crack resistance, the middle nano-hydrated calcium silicate gel has strong mechanical properties and waterproofness, and the inner acrylate-siloxane polymer emulsion can improve the bonding force and weather resistance of asphalt concrete, thereby forming multi-level protection for asphalt concrete and significantly improving the anti-stripping performance of asphalt concrete;

[0139] (4) The core layer and the shell layer of the core-shell polymer emulsion in the present invention have different glass transition temperatures, forming a gradient change in shear modulus, which can effectively disperse temperature stress, thereby improving the high-temperature stability of the asphalt anti-stripping agent;

[0140] (5) In the preparation method of the present invention, the prepared core-shell polymer emulsion is heated to the first preset temperature, and then the siloxane-modified nano-hydrated calcium silicate gel and the hindered phenol-modified bio-based elastomer are added in sequence; heating enhances the fluidity of the core-shell polymer emulsion, facilitating the uniform dispersion of subsequent components, and an appropriate temperature helps the subsequent interfacial reaction to proceed. The modified nano-hydrated calcium silicate gel forms chemical bonds with the core-shell structure polymer emulsion and the bio-based elastomer respectively; and the molten bio-based elastomer can better mix with other components and form a stable interface through physical entanglement and chemical bonding. Therefore, the preparation method of the present invention realizes the close synergistic effect between components through hierarchical grafting and interface optimization, thereby effectively dispersing stress, inhibiting crack propagation, and enhancing the adaptability to environmental changes, comprehensively improving the durability and anti-stripping property of asphalt;

[0141] (6) The present invention uses a bio-based elastomer and a siloxane-modified nano-hydrated calcium silicate gel, which has a lower synthesis cost than traditional materials and a high proportion of bio-based components, significantly reducing manufacturing carbon emissions; moreover, the design of the gradient composite structure improves the performance while optimizing the material usage efficiency, achieving a breakthrough balance between cost and performance;

[0142] (7) In the present invention, the γ-aminopropyltrimethoxysilane-modified nano-hydrated calcium silicate gel can, on the one hand, form a hydrogen bond network with the hydroxyl groups on the surface of the aggregate, reduce the porosity at the interface between the asphalt and the aggregate, and enhance the interfacial bonding force, thereby significantly improving the anti-stripping performance; on the other hand, the dispersibility of the modified nano-hydrated calcium silicate gel is significantly improved, forming a reinforcing network with a size of 50 - 200 nm, further improving the mechanical strength of the asphalt. In addition, the bio-based elastomer is in-situ grafted onto the γ-aminopropyltrimethoxysilane-modified nano-hydrated calcium silicate gel to form an interpenetrating polymer network structure, significantly enhancing the low-temperature anti-cracking performance of the asphalt;

[0143] (8) In the present invention, the bio-based elastomer modified with hindered phenol can effectively inhibit the oxidation reaction and delay the aging of the asphalt, thereby improving the anti-freeze-thaw cycle performance of the asphalt.

[0144] The above are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed with preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, making some changes or modifications using the disclosed technical content is equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. An asphalt anti-stripping agent, characterized in that: The anti-stripping agent comprises, by weight: 80-90 parts of core-shell polymer emulsion, 1-3 parts of siloxane-modified nano-hydrated calcium silicate gel, 5-8 parts of bio-based elastomer / hindered phenol-modified bio-based elastomer, 0.5-1.5 parts of surfactant, and 0.1-0.3 parts of quaternary ammonium salt.

2. The asphalt anti-stripping agent according to claim 1, characterized in that The core-shell polymer emulsion is an acrylate-siloxane polymer emulsion; The core layer monomer of the core-shell polymer emulsion is acrylate, and the shell layer monomer of the core-shell polymer emulsion is siloxane.

3. The asphalt anti-stripping agent according to claim 2, characterized in that: The glass transition temperature of the core layer monomer is 15°C-20°C; The glass transition temperature of the shell monomer is -55°C to -65°C.

4. The asphalt anti-stripping agent according to claim 2, characterized in that: The siloxane-modified nano-hydrated calcium silicate gel is γ-aminopropyltrimethoxysilane-modified nano-hydrated calcium silicate gel.

5. A method for preparing an asphalt anti-stripping agent, characterized in that: The following steps are involved: 80-90 parts of a core-shell polymer emulsion are prepared using 56-63 parts by weight of a core layer monomer and 24-27 parts by weight of a shell layer monomer; After heating 80-90 parts by weight of a core-shell polymer emulsion to a first preset temperature, 1-3 parts by weight of a siloxane-modified nano-hydrated calcium silicate gel, 5-8 parts by weight of a bio-based elastomer / hindered phenol-modified bio-based elastomer, 0.5-1.5 parts of a surfactant and 0.1-0.3 parts of a quaternary ammonium salt are sequentially added to the core-shell polymer emulsion, and the mixture is stirred at a preset speed for a first preset time to obtain an asphalt anti-stripping agent.

6. The method for preparing an asphalt anti-stripping agent according to claim 5, characterized in that: The preparation method of the core-shell polymer emulsion is specifically as follows: 160-200 parts by weight of deionized water, 0.15-0.3 parts by weight of an emulsifier, and 0.05-0.15 parts by weight of an initiator are uniformly mixed and heated to a second preset temperature to obtain a first mixed solution; Adding 56 to 63 parts by weight of the core layer monomer dropwise to the first mixed solution for a second preset time, and then reacting for a third preset time to obtain a core layer emulsion; 24 to 27 parts by weight of the shell monomer and 0.35 to 0.7 parts by weight of the emulsifier are mixed evenly to obtain a second mixed solution; The second mixed liquid is added dropwise to the core layer emulsion under heat preservation for a fourth preset time, and then the mixture is reacted under heat preservation for a fifth preset time to obtain 80-90 parts of a core-shell polymer emulsion.

7. The method for preparing an asphalt anti-stripping agent according to claim 5 or 6, characterized in that: The preparation method of the siloxane-modified nano-hydrated calcium silicate gel is specifically as follows: Dispersing 1-3 parts by weight of nano calcium silicate hydrate gel in an ethanol solution, and ultrasonically treating for a sixth preset time to obtain a dispersion; the volume of the ethanol solution is 5-10 times the mass of the nano calcium silicate hydrate gel; Adding γ-aminopropyltrimethoxysilane to the dispersion, and reflux reacting at a third preset temperature for 2h-3h to obtain a third mixed solution; wherein the amount of γ-aminopropyltrimethoxysilane added is 3%-5% of the mass of the nano-hydrated calcium silicate gel; The third mixed liquid is centrifuged, washed and dried to obtain siloxane-modified nano-hydrated calcium silicate gel.

8. The method for preparing an asphalt anti-stripping agent according to claim 7, characterized in that: The preparation method of the hindered phenol-modified bio-based elastomer is specifically as follows: heating 5 to 8 parts by weight of a bio-based elastomer to a fourth preset temperature to obtain a molten bio-based elastomer; Adding a hindered phenol antioxidant to the melted bio-based elastomer and stirring evenly to obtain a hindered phenol-modified bio-based elastomer; The amount of the hindered phenol antioxidant is 0.1%-0.5% of the mass of the bio-based elastomer.

9. The method for preparing an asphalt anti-stripping agent according to claim 8, characterized in that: The first preset temperature is 40°C-50°C, the second preset temperature is 70°C-80°C, the third preset temperature is 60°C-70°C, and the fourth preset temperature is 60°C-70°C; The first preset time is 30min-60min, the second preset time is 1h-1.5h, the third preset time is 1h-1.5h, the fourth preset time is 1h-2h, the fifth preset time is 2h-3h, and the sixth preset time is 30min-60min; The preset speed is 500rpm-1000rpm.

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