A kind of preparation method of anti-aging asphalt regeneration agent and regenerated asphalt mixture

Abstract

The present invention discloses a method for preparing an anti-aging asphalt regeneration agent and a regenerated asphalt mixture. The anti-aging asphalt regeneration agent includes component A and component B. In terms of weight, component A includes: 10 to 12 parts of base oil, 6 to 8 parts of polyaspartic acid ester, and 3 to 5 parts of polyaspartic acid ester intercalation modified montmorillonite; component B includes an isocyanate curing agent. The present invention uses asparagine polyurea resin and low-viscosity oil as asphalt regeneration agents, which can effectively restore the viscoelasticity and rheology of aged asphalt and improve its road performance; and adds montmorillonite modified by polyaspartic acid ester intercalation as an anti-aging agent, which can effectively improve the anti-aging performance of the regenerated asphalt mixture.

Description

Technical Field

[0001] The invention relates to the technical field of regenerated asphalt concrete, and in particular to a method for preparing an aging-resistant asphalt regeneration agent and a regenerated asphalt mixture. Background Art

[0002] Asphalt concrete pavement will slowly age under natural conditions after a period of use, which can easily cause the asphalt to harden and become brittle, and lose its proper physical properties, thus affecting road performance. Coupled with the effects of water and vehicle load, the road surface disease will be aggravated. With the increasing number of pavement maintenance and renovation and expansion projects, the amount of waste asphalt will become larger and larger. Recycling asphalt pavements that do not meet performance standards can make full use of the waste generated by the original asphalt pavement, save a lot of asphalt, reduce construction costs, and at the same time reduce the occupation of land resources by waste and protect the environment.

[0003] Asphalt pavement regeneration technology is to dig up, recycle, crush, and screen old pavement materials that need to be renovated or abandoned, and then mix them with regeneration agents, new aggregates, and new asphalt materials appropriately to form a regenerated asphalt mixture with certain road performance. The restoration of the road performance of the abandoned asphalt mixture mainly depends on the restoration of its asphalt viscoelasticity, which is mostly achieved with the help of regeneration agents. It can be seen that the performance of the regeneration agent directly affects the regeneration effect of the abandoned asphalt mixture.

[0004] At present, a mixture of low-viscosity oil and resin is generally used as an asphalt regeneration agent to soften aged asphalt and restore its rheological properties and viscoelasticity. The existing regeneration agent generally uses epoxy resin as its resin component to improve the adhesion and fatigue resistance of the regenerated asphalt. However, epoxy resin has poor toughness and weather resistance. Using it as a regeneration agent component is not conducive to improving the road performance of the regenerated asphalt mixture. In addition, the aging resistance of the regenerated asphalt mixture will also be lower than that of the new asphalt mixture, resulting in a shorter service life of the regenerated asphalt pavement. Summary of the invention

[0005] The present invention aims to overcome the problems in the prior art that when epoxy resin is used as a component of a waste asphalt mixture regeneration agent, its toughness and weather resistance are poor, which is not conducive to improving the road performance of the regenerated asphalt mixture; and the aging resistance of the obtained regenerated asphalt mixture is also reduced compared with that of a new asphalt mixture, resulting in a shorter service life of the regenerated asphalt pavement. The present invention provides an aging-resistant asphalt regeneration agent and a method for preparing a regenerated asphalt mixture. Asparagus polyurea resin and low-viscosity oil are used as regeneration agents, which can effectively restore the viscoelasticity and rheology of aged asphalt and improve its road performance; and intercalated modified montmorillonite is added as an anti-aging agent, which can effectively improve the aging resistance of the regenerated asphalt mixture.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] An anti-aging asphalt rejuvenating agent comprises a component A and a component B; in parts by weight, the component A comprises: 10 to 12 parts of base oil, 6 to 8 parts of polyaspartic acid ester, and 3 to 5 parts of polyaspartic acid ester intercalated modified montmorillonite; the component B comprises an isocyanate curing agent;

[0008] The preparation method of the polyaspartic acid ester intercalation modified montmorillonite comprises the following steps:

[0009] (1) subjecting dimethyl maleate to a Michael addition reaction with a C12-C16 straight-chain aliphatic diamine to obtain an initial polyaspartic acid ester; the molar ratio of the straight-chain aliphatic diamine to dimethyl maleate is 1:2-2.4;

[0010] (2) subjecting the initial polyaspartic acid ester to an ester exchange reaction with 2-hydroxypropyltrimethylammonium chloride to obtain a quaternary ammonium salt modified polyaspartic acid ester; the molar ratio of 2-hydroxypropyltrimethylammonium chloride to dimethyl maleate added in step (1) is 2 to 2.4:1;

[0011] (3) respectively adding quaternary ammonium salt modified polyaspartic acid ester and sodium montmorillonite into water, stirring evenly to obtain a quaternary ammonium salt modified polyaspartic acid ester solution and a montmorillonite dispersion, mixing the quaternary ammonium salt modified polyaspartic acid ester solution and the montmorillonite dispersion, stirring and reacting to obtain the polyaspartic acid ester intercalation modified montmorillonite; the mass ratio of the quaternary ammonium salt modified polyaspartic acid ester to the sodium montmorillonite is 7-8:10.

[0012] In the asphalt regeneration agent of the present invention, the base oil can increase the content of oil in the asphalt to achieve the effect of softening and reconciling the aged asphalt, so that the rheological properties of the waste asphalt can be restored. In order to further improve the high and low temperature performance and viscosity toughness of the regenerated asphalt, so that the regenerated asphalt mixture can meet the use requirements of high-grade asphalt pavement, the present invention adds polyaspartic acid ester and isocyanate curing agent to the regeneration agent, and polyaspartic acid ester and isocyanate curing agent can generate asparagine polyurea resin after reaction, which has the advantages of high toughness and good weather resistance compared with epoxy resin. The addition of asparagine polyurea resin can enhance the elastic skeleton of the asphalt microstructure, improve the extension ability and bonding performance of the regenerated asphalt, and improve the high temperature recovery performance, anti-rutting performance and anti-low temperature cracking ability of the regenerated asphalt mixture.

[0013] At the same time, polyaspartic acid ester intercalation modified montmorillonite is added to the regeneration agent of the present invention as an anti-aging agent. The addition of montmorillonite can enhance the resistance of asphalt to permanent deformation, and its lamellar structure can effectively block the penetration of oxygen in asphalt, thereby slowing down the thermal oxygen aging of asphalt, improving the aging resistance of regenerated asphalt, and extending the service life of regenerated asphalt pavement. However, montmorillonite has a huge specific surface area and is very easy to agglomerate. In addition, the compatibility between inorganic montmorillonite and organic asphalt matrix is ​​poor. If montmorillonite is directly added to regenerated asphalt, it will cause a decrease in the road performance of regenerated asphalt. In order to improve the bonding force between montmorillonite and the regenerated asphalt matrix, the present invention uses polyaspartic acid ester to intercalate montmorillonite. The present invention introduces cationic quaternary ammonium salt groups into polyaspartic acid esters, and through the exchange reaction between the quaternary ammonium salt groups and the inorganic cations between the sodium-based montmorillonite layers, the polyaspartic acid esters enter between the montmorillonite layers, increase the interlayer spacing, and the surface is also covered by organic cations, so that the montmorillonite changes from hydrophilic to lipophilic; when the regeneration agent is mixed and added to the waste asphalt, the polyaspartic acid esters between the intercalated modified montmorillonite layers can react with the isocyanate curing agent to obtain asparagine polyurea resin, so that the interlayer spacing of the montmorillonite is further increased to obtain an intercalated or peeled composite material, effectively improving the dispersibility of montmorillonite between the regenerated asphalt matrix and its binding force with the regenerated asphalt matrix, which is conducive to the improvement of the road performance and aging resistance of the regenerated asphalt. The present invention adopts C12~C16 straight-chain aliphatic diamines to react with dimethyl maleate to prepare polyaspartic acid esters, which can improve the flexibility of the polyaspartic acid ester molecular chain and facilitate its entry into the interlayer of montmorillonite.

[0014] Preferably, the reaction conditions of step (1) are as follows: a linear aliphatic diamine is mixed with dimethyl maleate, 200-500 ppm of sodium methoxide catalyst is added, and the mixture is reacted at 60-80° C. for 6-8 hours under nitrogen protection to obtain the initial polyaspartic acid ester.

[0015] Preferably, the reaction conditions of step (2) are as follows: the initial polyaspartic acid ester is mixed with a 2-hydroxypropyltrimethylammonium chloride solution, and 200-500 ppm of p-toluenesulfonic acid catalyst is added, and the mixture is stirred evenly and reacted at 130-150° C. for 4-6 hours, and the quaternary ammonium salt-modified polyaspartic acid ester is obtained after removing the solvent.

[0016] Preferably, in step (3), the quaternary ammonium salt modified polyaspartic acid ester solution and the montmorillonite dispersion are mixed, and then stirred at 60-80° C. for 2-4 hours to obtain the polyaspartic acid ester intercalation modified montmorillonite.

[0017] Preferably, the polyaspartic acid ester is modified by silane and hydroxytyrosol, and its preparation method is:

[0018] (a) subjecting ethylene glycol monoallyl ether to a hydrosilylation reaction with triethoxysilane to obtain terminal hydroxyl triethoxysilane; the molar ratio of ethylene glycol monoallyl ether to triethoxysilane is 1:1-1.2; the reaction conditions are: adding ethylene glycol monoallyl ether and triethoxysilane to tetrahydrofuran, adding 5-10 ppm of chloroplatinic acid catalyst, refluxing at 120-150° C. for 2-3 hours, and removing the solvent to obtain the terminal hydroxyl triethoxysilane;

[0019] (b) firstly subjecting hydroxytyrosol to transesterification reaction with dimethyl maleate, and then adding the terminal hydroxy triethoxy silane obtained in step (b) to continue transesterification reaction to obtain modified maleate; the molar ratio of hydroxytyrosol, terminal hydroxy triethoxy silane and dimethyl maleate is 1-2:2-3:2; the reaction conditions are: mixing dimethyl maleate and xylene solution of hydroxytyrosol, adding 200-500 ppm of p-toluenesulfonic acid catalyst, stirring evenly and reacting at 130-150° C. for 1-2 hours; then adding terminal hydroxy triethoxy silane dropwise, continuing the reaction at 130-150° C. for 3-5 hours, and removing the solvent to obtain modified maleate;

[0020] (c) subjecting the modified dimethyl maleate obtained in step (b) to a Michael addition reaction with a C6-C12 straight-chain aliphatic diamine to obtain the polyaspartic acid ester; the molar ratio of the straight-chain aliphatic diamine to the modified dimethyl maleate is 1:2-2.4; the reaction conditions are: mixing the straight-chain aliphatic diamine with the modified maleate, adding 200-500 ppm of sodium methoxide catalyst, and reacting at 60-80° C. for 6-8 hours under nitrogen protection to obtain the polyaspartic acid ester.

[0021] Asphalt is a high molecular weight concentrated solution formed by asphaltene as solute and soft asphaltene (saturated fraction, aromatic fraction, etc.) as solvent. During the aging process of asphalt, the content and structure of each component compound change, causing the solubility parameters of asphaltene and soft asphaltene to change, resulting in a decrease in the compatibility of asphaltene and soft asphaltene, which ultimately manifests as a decrease in the road performance of asphalt. In order to increase the compatibility of asphaltene and soft asphaltene in the aged asphalt, thereby realizing the regeneration of the aged asphalt, in the process of preparing polyaspartic acid ester, the present invention uses hydroxytyrosol to modify maleic acid ester, and adopts C6~C12 straight-chain aliphatic diamine to react with the modified maleic acid ester. Through the ester exchange reaction of hydroxytyrosol and maleic acid ester, an aromatic group with a polar group can be introduced into the molecular chain of the product. Therefore, the polyaspartic acid ester obtained by the present invention contains polar aromatic groups and non-polar straight-chain alkyl groups at the same time, so that it has amphiphilicity: the non-polar straight-chain alkyl chain segment can be combined with soft asphaltene with weaker polarity, and the part with polar groups can adsorb asphaltene with strong polarity. Therefore, the polyaspartic acid ester in the present invention can be used as an interface agent to form a stable solution of asphaltene and soft asphaltene, two components with different polarities, effectively improving the compatibility of each component in the asphalt, so that the regenerated asphalt has good road performance.

[0022] At the same time, the present invention introduces ether bonds and siloxane groups into polyaspartic acid esters through the ester exchange reaction of terminal hydroxy triethoxy silane and maleic acid ester, thereby increasing the flexibility of the resin molecular chain, reducing the viscosity of the resin, and improving its permeability in asphalt, thereby improving the mixing properties of the regeneration agent and waste asphalt mixture; and through the control of the length of the straight-chain alkyl molecular chain in the diamine, the curing time of the resin is extended, so that the regenerated asphalt mixture has sufficient operating time, ensuring that the regeneration agent has good performance.

[0023] Preferably, the base oil is an aromatic oil with an aromatic content of ≥75wt%.

[0024] Preferably, the mass ratio of component A to component B is 15:2-5.

[0025] The present invention also provides a method for preparing a recycled asphalt mixture, comprising the following steps:

[0026] S1: milling the aged asphalt pavement to obtain waste asphalt mixture;

[0027] S2: preheating and keeping the waste asphalt mixture, aggregate and new asphalt warm;

[0028] S3: adding an anti-aging asphalt regeneration agent to the preheated waste asphalt mixture and mixing; then adding the preheated aggregate and continuing to mix; and then adding new asphalt and mineral powder in sequence, and obtaining the regenerated asphalt mixture after mixing.

[0029] Preferably, the addition amount of each component in S3 is, in parts by weight: 300-500 parts of waste asphalt mixture, 400-600 parts of aggregate, 10-30 parts of new asphalt, and 50-200 parts of mineral powder; the added mass of the anti-aging asphalt regeneration agent is 8-12% of the mass of the waste asphalt mixture.

[0030] Preferably, the preheating temperature of the waste asphalt mixture in S2 is 100~140°C, the preheating temperature of the aggregate is 170~210°C, and the preheating temperature of the new asphalt is 160~170°C; the mixing temperature in S3 is 175~185°C.

[0031] Therefore, the present invention has the following beneficial effects:

[0032] (1) Using asparagus polyurea resin and base oil as components of asphalt regeneration agent can effectively restore the performance of aged asphalt. By utilizing the good toughness and weather resistance of asparagus polyurea resin, the recycled asphalt mixture can have good resistance to low-temperature cracking and high-temperature rutting, thereby improving its road performance;

[0033] (2) Polyaspartic acid ester intercalated modified montmorillonite is added to the regeneration agent as an anti-aging agent. The addition of montmorillonite can enhance the asphalt's ability to resist permanent deformation, and its lamellar structure can effectively block the penetration of oxygen in the asphalt, thereby slowing down the thermal oxidation aging of the asphalt; the polyaspartic acid ester between the intercalated modified montmorillonite layers can react with the isocyanate curing agent to obtain asparagine polyurea resin, which further increases the interlayer spacing of the montmorillonite to obtain an intercalated or exfoliated composite material, effectively improving the dispersibility of montmorillonite in the regenerated asphalt matrix and its bonding strength with the regenerated asphalt matrix;

[0034] (3) Polyaspartic acid esters are prepared by reacting maleic acid esters modified with hydroxytyrosol with C6-C12 straight-chain aliphatic diamines, so that the polyaspartic acid esters in the regeneration agent have amphiphilicity, which can improve the compatibility between asphaltene and soft asphaltene in asphalt, thereby improving the performance of the regenerated asphalt;

[0035] (4) The polyaspartic acid ester was modified with end-hydroxy triethoxysilane to reduce the viscosity of the resin and improve the mixing properties of the regeneration agent with the waste asphalt mixture. By controlling the length of the linear alkyl molecular chain in the diamine, the curing time of the resin was extended, so that the recycled asphalt mixture had sufficient operating time. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with specific implementation methods.

[0037] Embodiment 1:

[0038] An anti-aging asphalt rejuvenating agent, comprising component A and component B in a mass ratio of 5:1, wherein, in parts by weight, component A comprises 11 parts of second-line extraction oil (aromatic content 76.7%), 7 parts of polyaspartic acid ester and 4 parts of polyaspartic acid ester intercalated modified montmorillonite; component B is an isocyanate curing agent (Wanhua HT100);

[0039] Wherein, the preparation method of polyaspartic acid ester is:

[0040] (a) Ethylene glycol monoallyl ether and triethoxysilane were added to tetrahydrofuran in a molar ratio of 1:1.1, and 8 ppm of chloroplatinic acid catalyst was added, and the mixture was refluxed at 130° C. for 2.5 h, and the solvent was removed to obtain terminal hydroxy triethoxysilane;

[0041] (b) mixing dimethyl maleate and a xylene solution of hydroxytyrosol, adding 300 ppm of p-toluenesulfonic acid catalyst, stirring evenly, and performing an ester exchange reaction at 140° C. for 1.5 hours; then dripping the terminal hydroxy triethoxy silane obtained in step (a), continuing the reaction at 140° C. for 4 hours, and removing the solvent to obtain a modified maleate; wherein the molar ratio of the added hydroxytyrosol, terminal hydroxy triethoxy silane and dimethyl maleate is 1.5:2.5:2;

[0042] (c) mixing dodecanediamine and the modified maleate obtained in step (b) at a molar ratio of 1:2.1, adding 300 ppm of sodium methoxide catalyst, and reacting at 70° C. for 7 hours under nitrogen protection to obtain the polyaspartic acid ester;

[0043] The preparation method of polyaspartic acid ester intercalation modified montmorillonite is:

[0044] (1) dodecanediamine and dimethyl maleate were mixed in a molar ratio of 1:2.1, and 300 ppm of sodium methoxide catalyst was added, and the mixture was reacted at 70° C. for 7 h under nitrogen protection to obtain initial polyaspartic acid ester;

[0045] (2) mixing the initial polyaspartic acid ester with an ethanol solution of 2-hydroxypropyltrimethylammonium chloride, adding 300 ppm of p-toluenesulfonic acid catalyst, stirring evenly, and performing an ester exchange reaction at 140° C. for 5 hours. After removing the solvent, a quaternary ammonium salt-modified polyaspartic acid ester is obtained; the molar ratio of 2-hydroxypropyltrimethylammonium chloride to dimethyl maleate added in step (1) is 2.2:1;

[0046] (3) Adding quaternary ammonium salt-modified polyaspartic acid ester and commercially available sodium montmorillonite (ion exchange capacity: 130 mmol / 100 g) into water respectively, stirring evenly to obtain a quaternary ammonium salt-modified polyaspartic acid ester solution with a concentration of 1 g / L and a montmorillonite dispersion with a concentration of 2 g / L, mixing the quaternary ammonium salt-modified polyaspartic acid ester solution and the montmorillonite dispersion to make a mass ratio of the quaternary ammonium salt-modified polyaspartic acid ester to the sodium montmorillonite of 7.5:10; stirring and reacting at 70° C. for 3 h to obtain the polyaspartic acid ester intercalation-modified montmorillonite.

[0047] A method for preparing a recycled asphalt mixture, comprising the following steps:

[0048] S1: milling the aged asphalt pavement to obtain waste asphalt mixture, crushing and screening the waste asphalt mixture to obtain RAP fine material with a particle size of less than 4.75 mm and RAP coarse material with a particle size of 4.75-26.5 mm;

[0049] S2: Preheat RAP fine material and RAP coarse material at 120℃ for 1h and keep them warm; preheat new No. 70 asphalt at 165℃ for 3h and keep them warm; preheat aggregate at 190℃ for 3h and keep them warm; the aggregate includes coarse aggregate and fine aggregate, the coarse aggregate is basalt aggregate with a particle size of 4.75~26.5mm, and the fine aggregate is machine-made sand with a particle size of ≤2.36mm;

[0050] S3: In parts by weight, 100 parts of preheated RAP fine aggregate and 200 parts of preheated RAP coarse aggregate are mixed, and 25 parts of component A of aging-resistant asphalt regeneration agent and 5 parts of component B of aging-resistant asphalt regeneration agent are added, and the mixture is stirred at 180°C for 35 seconds; then 250 parts of preheated coarse aggregate and 320 parts of preheated fine aggregate are added, and the mixture is stirred at 180°C for 35 seconds; then 30 parts of new No. 70 asphalt are added, and the mixture is stirred at 180°C for 30 seconds, and finally 130 parts of mineral powder are added, and the mixture is stirred at 180°C to obtain the regenerated asphalt mixture.

[0051] Embodiment 2:

[0052] An anti-aging asphalt rejuvenator, comprising component A and component B in a mass ratio of 3:1, wherein, in parts by weight, component A comprises 10 parts of second-line extraction oil (aromatic content 76.7%), 6 parts of polyaspartic acid ester and 3 parts of polyaspartic acid ester intercalated modified montmorillonite; component B is an isocyanate curing agent (Wanhua HT100);

[0053] Wherein, the preparation method of polyaspartic acid ester is:

[0054] (a) Ethylene glycol monoallyl ether and triethoxysilane are added to tetrahydrofuran in a molar ratio of 1:1, and 5 ppm of chloroplatinic acid catalyst is added, and the mixture is refluxed at 150° C. for 2 h, and the solvent is removed to obtain terminal hydroxy triethoxysilane;

[0055] (b) mixing dimethyl maleate and a xylene solution of hydroxytyrosol, adding 200 ppm of p-toluenesulfonic acid catalyst, stirring evenly, and performing an ester exchange reaction at 150° C. for 1 hour; then dripping the terminal hydroxy triethoxy silane obtained in step (a), continuing the reaction at 150° C. for 3 hours, and removing the solvent to obtain a modified maleate; wherein the molar ratio of the added hydroxytyrosol, terminal hydroxy triethoxy silane and dimethyl maleate is 1:3:2;

[0056] (c) mixing dodecanediamine and the modified maleate obtained in step (b) at a molar ratio of 1:2.4, adding 200 ppm of sodium methoxide catalyst, and reacting at 80° C. for 6 hours under nitrogen protection to obtain the polyaspartic acid ester;

[0057] The preparation method of polyaspartic acid ester intercalation modified montmorillonite is:

[0058] (1) dodecanediamine and dimethyl maleate in a molar ratio of 1:2 were mixed, and 500 ppm of sodium methoxide catalyst was added, and the mixture was reacted at 60° C. for 8 h under nitrogen protection to obtain initial polyaspartic acid ester;

[0059] (2) mixing the initial polyaspartic acid ester with an ethanol solution of 2-hydroxypropyltrimethylammonium chloride, adding 500 ppm of p-toluenesulfonic acid catalyst, stirring evenly, and performing an ester exchange reaction at 130° C. for 6 hours. After removing the solvent, a quaternary ammonium salt-modified polyaspartic acid ester is obtained; the molar ratio of 2-hydroxypropyltrimethylammonium chloride to dimethyl maleate added in step (1) is 2.4:1;

[0060] (3) Adding quaternary ammonium salt-modified polyaspartic acid ester and commercially available sodium montmorillonite (ion exchange capacity: 130 mmol / 100 g) into water respectively, stirring evenly to obtain a quaternary ammonium salt-modified polyaspartic acid ester solution with a concentration of 1 g / L and a montmorillonite dispersion with a concentration of 2 g / L, mixing the quaternary ammonium salt-modified polyaspartic acid ester solution and the montmorillonite dispersion to make a mass ratio of the quaternary ammonium salt-modified polyaspartic acid ester to the sodium montmorillonite of 7:10; stirring and reacting at 60° C. for 4 h to obtain the polyaspartic acid ester intercalation-modified montmorillonite.

[0061] A method for preparing a recycled asphalt mixture, comprising the following steps:

[0062] S1: milling the aged asphalt pavement to obtain waste asphalt mixture, crushing and screening the waste asphalt mixture to obtain RAP fine material with a particle size of less than 4.75 mm and RAP coarse material with a particle size of 4.75-26.5 mm;

[0063] S2: Preheat RAP fine material and RAP coarse material at 100℃ for 2h and keep them warm; preheat new No. 70 asphalt at 160℃ for 3h and keep them warm; preheat aggregate at 170℃ for 3h and keep them warm; the aggregate includes coarse aggregate and fine aggregate, the coarse aggregate is basalt aggregate with a particle size of 4.75~26.5mm, and the fine aggregate is machine-made sand with a particle size of ≤2.36mm;

[0064] S3: In parts by weight, 150 parts of preheated RAP fine aggregate and 250 parts of preheated RAP coarse aggregate are mixed, and 24 parts of component A of aging-resistant asphalt regeneration agent and 8 parts of component B of aging-resistant asphalt regeneration agent are added, and the mixture is stirred at 175°C for 35 seconds; then 200 parts of preheated coarse aggregate and 300 parts of preheated fine aggregate are added, and the mixture is stirred at 175°C for 35 seconds; then 15 parts of new No. 70 asphalt are added, and the mixture is stirred at 175°C for 30 seconds, and finally 100 parts of mineral powder are added, and the mixture is stirred at 175°C to obtain the regenerated asphalt mixture.

[0065] Embodiment 3:

[0066] An anti-aging asphalt rejuvenating agent, comprising component A and component B in a mass ratio of 15:2, wherein, in parts by weight, component A comprises 12 parts of second-line extraction oil (aromatic content 76.7%), 8 parts of polyaspartic acid ester and 5 parts of polyaspartic acid ester intercalated modified montmorillonite; component B is an isocyanate curing agent (Wanhua HT100);

[0067] Wherein, the preparation method of modified polyaspartic acid ester is:

[0068] (a) Ethylene glycol monoallyl ether and triethoxysilane are added to tetrahydrofuran in a molar ratio of 1:1.2, and 10 ppm of chloroplatinic acid catalyst is added, and the mixture is refluxed at 120° C. for 3 h, and the solvent is removed to obtain terminal hydroxy triethoxysilane;

[0069] (b) mixing dimethyl maleate and a xylene solution of hydroxytyrosol, adding 500 ppm of p-toluenesulfonic acid catalyst, stirring evenly, and then performing an ester exchange reaction at 130° C. for 2 hours; then dripping the terminal hydroxy triethoxy silane prepared in step (a), continuing the reaction at 130° C. for 5 hours, and removing the solvent to obtain a modified maleate; wherein the molar ratio of the added hydroxytyrosol, terminal hydroxy triethoxy silane and dimethyl maleate is 2:2:2;

[0070] (c) mixing 1,6-hexanediamine and the modified maleate obtained in step (b) at a molar ratio of 1:2, adding 500 ppm of sodium methoxide catalyst, and reacting at 60° C. for 8 hours under nitrogen protection to obtain the modified polyaspartic acid ester;

[0071] The preparation method of polyaspartic acid ester intercalation modified montmorillonite is:

[0072] (1) Tetradecanediamine and dimethyl maleate in a molar ratio of 1:2.4 were mixed, and 200 ppm of sodium methoxide catalyst was added, and the mixture was reacted at 80° C. for 6 h under nitrogen protection to obtain initial polyaspartic acid ester;

[0073] (2) mixing the initial polyaspartic acid ester with an ethanol solution of 2-hydroxypropyltrimethylammonium chloride, adding 200 ppm of p-toluenesulfonic acid catalyst, stirring evenly, and performing an ester exchange reaction at 150° C. for 4 hours. After removing the solvent, a quaternary ammonium salt-modified polyaspartic acid ester is obtained; the molar ratio of 2-hydroxypropyltrimethylammonium chloride to dimethyl maleate added in step (1) is 2:1;

[0074] (3) Adding quaternary ammonium salt-modified polyaspartic acid ester and commercially available sodium montmorillonite (ion exchange capacity: 130 mmol / 100 g) into water respectively, stirring evenly to obtain a quaternary ammonium salt-modified polyaspartic acid ester solution with a concentration of 1 g / L and a montmorillonite dispersion with a concentration of 2 g / L, mixing the quaternary ammonium salt-modified polyaspartic acid ester solution and the montmorillonite dispersion to make a mass ratio of the quaternary ammonium salt-modified polyaspartic acid ester to the sodium montmorillonite of 8:10; stirring and reacting at 80° C. for 2 h to obtain the polyaspartic acid ester intercalation-modified montmorillonite.

[0075] A method for preparing a recycled asphalt mixture, comprising the following steps:

[0076] S1: milling the aged asphalt pavement to obtain waste asphalt mixture, crushing and screening the waste asphalt mixture to obtain RAP fine material with a particle size of less than 4.75 mm and RAP coarse material with a particle size of 4.75-26.5 mm;

[0077] S2: Preheat RAP fine material and RAP coarse material at 140℃ for 1h and keep them warm; preheat new No. 70 asphalt at 170℃ for 2h and keep them warm; preheat aggregate at 210℃ for 2h and keep them warm; the aggregate includes coarse aggregate and fine aggregate, the coarse aggregate is basalt aggregate with a particle size of 4.75~26.5mm, and the fine aggregate is machine-made sand with a particle size of ≤2.36mm;

[0078] S3: In parts by weight, 200 parts of preheated RAP fine aggregate and 300 parts of preheated RAP coarse aggregate are mixed, and 53 parts of component A of aging-resistant asphalt regeneration agent and 7 parts of component B of aging-resistant asphalt regeneration agent are added, and the mixture is stirred at 185°C for 35 seconds; then 175 parts of preheated coarse aggregate and 275 parts of preheated fine aggregate are added, and the mixture is stirred at 185°C for 35 seconds; then 20 parts of new No. 70 asphalt are added, and the mixture is stirred at 185°C for 30 seconds, and finally 50 parts of mineral powder are added, and the mixture is stirred at 185°C to obtain the regenerated asphalt mixture.

[0079] Comparative Example 1:

[0080] In the asphalt regeneration agent of Comparative Example 1, no polyaspartic acid ester intercalation modified montmorillonite is added to component A, and the rest is the same as in Example 1.

[0081] Comparative Example 2:

[0082] In the asphalt regeneration agent of Comparative Example 2, the preparation method of the polyaspartic acid ester intercalation modified montmorillonite in component A is:

[0083] (1) Mixing ethylenediamine and dimethyl maleate in a molar ratio of 1:2.1, adding 300 ppm of sodium methoxide catalyst, and reacting at 70°C for 7 hours under nitrogen protection to obtain initial polyaspartic acid ester;

[0084] (2) mixing the initial polyaspartic acid ester with an ethanol solution of 2-hydroxypropyltrimethylammonium chloride, adding 300 ppm of p-toluenesulfonic acid catalyst, stirring evenly, and performing an ester exchange reaction at 140° C. for 5 hours. After removing the solvent, a quaternary ammonium salt-modified polyaspartic acid ester is obtained; the molar ratio of 2-hydroxypropyltrimethylammonium chloride to dimethyl maleate added in step (1) is 2.2:1;

[0085] (3) adding quaternary ammonium salt-modified polyaspartic acid ester and commercially available sodium montmorillonite (ion exchange capacity 130 mmol / 100 g) to water respectively, stirring evenly to obtain a quaternary ammonium salt-modified polyaspartic acid ester solution with a concentration of 1 g / L and a montmorillonite dispersion with a concentration of 2 g / L, mixing the quaternary ammonium salt-modified polyaspartic acid ester solution and the montmorillonite dispersion to make the mass ratio of the quaternary ammonium salt-modified polyaspartic acid ester to the sodium montmorillonite be 7.5:10; stirring and reacting at 70° C. for 3 h to obtain the polyaspartic acid ester intercalation modified montmorillonite;

[0086] The rest are the same as in Example 1.

[0087] Comparative Example 3:

[0088] In the asphalt regeneration agent of comparative example 3, component A includes, by weight, 11 parts of second-line extraction oil (aromatic content 76.7%), 7 parts of polyaspartic acid ester and 4 parts of dodecyl dimethyl ammonium chloride intercalated modified montmorillonite;

[0089] The preparation method of dodecyldimethylammonium chloride intercalation modified montmorillonite is as follows: dodecyldimethylammonium chloride and commercially available sodium montmorillonite (ion exchange capacity 130mmol / 100g) are added into water respectively, stirred evenly to obtain a dodecyldimethylammonium chloride solution with a concentration of 1g / L and a montmorillonite dispersion liquid with a concentration of 2g / L, the dodecyldimethylammonium chloride solution and the montmorillonite dispersion liquid are mixed to make the mass ratio of dodecyldimethylammonium chloride to sodium montmorillonite be 7.5:10; the mixture is stirred and reacted at 70°C for 3h to obtain the dodecyldimethylammonium chloride intercalation modified montmorillonite;

[0090] The rest are the same as in Example 1.

[0091] Comparative Example 4:

[0092] In the asphalt regeneration agent of Comparative Example 4, polyaspartic acid ester is not added to component A, and the rest is the same as in Example 1.

[0093] Comparative Example 5:

[0094] In the asphalt regeneration agent used in Comparative Example 5, the preparation method of the polyaspartic acid ester in component A is:

[0095] (1) Ethylene glycol monoallyl ether and triethoxysilane were added to tetrahydrofuran in a molar ratio of 1:1.1, and 8 ppm of chloroplatinic acid catalyst was added, and the mixture was refluxed at 130° C. for 2.5 h. After removing the solvent, terminal hydroxy triethoxysilane was obtained;

[0096] (2) dimethyl maleate and terminal hydroxy triethoxy silane are mixed, and 300 ppm of p-toluenesulfonic acid catalyst is added, and after stirring evenly, an ester exchange reaction is carried out at 140° C. for 5 hours to obtain a modified maleate; wherein the molar ratio of the added terminal hydroxy triethoxy silane to dimethyl maleate is 4:2;

[0097] (3) mixing dodecanediamine and the modified maleate obtained in step (2) at a molar ratio of 1:2.1, adding 300 ppm of sodium methoxide catalyst, and reacting at 70° C. for 7 h under nitrogen protection to obtain the modified polyaspartic acid ester;

[0098] The rest are the same as in Example 1.

[0099] Comparative Example 6:

[0100] In the asphalt regeneration agent used in Comparative Example 6, the preparation method of the polyaspartic acid ester in component A is:

[0101] (1) Ethylene glycol monoallyl ether and triethoxysilane were added to tetrahydrofuran in a molar ratio of 1:1.1, and 8 ppm of chloroplatinic acid catalyst was added, and the mixture was refluxed at 130° C. for 2.5 h. After removing the solvent, terminal hydroxy triethoxysilane was obtained;

[0102] (2) Mix dimethyl maleate and a xylene solution of hydroxytyrosol, add 300 ppm of p-toluenesulfonic acid catalyst, stir evenly, and perform ester exchange reaction at 140° C. for 1.5 hours; then dropwise add the terminal hydroxy triethoxy silane obtained in step (1), continue the reaction at 140° C. for 4 hours, and remove the solvent to obtain a modified maleate; wherein the molar ratio of the added hydroxytyrosol, terminal hydroxy triethoxy silane and dimethyl maleate is 1.5:2.5:2;

[0103] (3) mixing ethylenediamine and the modified maleate obtained in step (2) at a molar ratio of 1:2.1, adding 300 ppm of sodium methoxide catalyst, and reacting at 70° C. for 7 h under nitrogen protection to obtain the modified polyaspartic acid ester;

[0104] The rest are the same as in Example 1.

[0105] 1. Test of regeneration performance and aging resistance of regeneration agent

[0106] The waste asphalt mixture was extracted by centrifugal separation, and the solvent was separated by rotary evaporation to obtain waste aged asphalt; the asphalt regeneration agent prepared in the above embodiment and comparative example was mixed with the waste aged asphalt at a mass ratio of 1:10, and stirred at 150° C. for 1 hour to obtain regenerated asphalt; the properties of the regenerated asphalt and the waste aged asphalt were tested according to the method in JTG E20 2011 "Testing Procedures for Asphalt and Asphalt Mixtures for Highway Engineering", and the results are shown in Table 1;

[0107] The film oven aging method was used to simulate the aging of the recycled asphalt. The aging temperature was 165°C and the aging time was 5 h. The various properties of the asphalt after simulated aging were tested. The results are shown in Table 2.

[0108] Table 1: Recycled asphalt performance test results.

[0109] Needle penetration / 0.1mm Softening point / ℃ Elongation (15℃) / cm 135℃ viscosity / Pa·S New asphalt (70#) 68.8 48.5 ＞150 0.55 Waste aged asphalt 30.5 69.5 8.7 2.03 Example 1 68.0 49.3 ＞150 30.6 Example 2 68.5 48.9 ＞150 33.5 Example 3 67.9 49.5 ＞150 35.3 Comparative Example 1 69.4 48.2 ＞150 28.7 Comparative Example 2 63.7 51.6 138 36.2 Comparative Example 3 66.5 50.8 133 31.1 Comparative Example 4 70.5 47.2 92 11.5 Comparative Example 5 65.2 51.2 116 27.3 Comparative Example 6 66.1 50.7 122 31.8

[0110] Table 2: Asphalt performance test results after film oven aging.

[0111] Penetration residual ratio / % Softening point increase value / ℃ Elongation residual ratio / % Example 1 83.5 2.8 56.5 Example 2 84.6 2.6 57.3 Example 3 85.1 2.3 58.6 Comparative Example 1 62.6 5.7 22.5 Comparative Example 2 71.3 3.6 38.5 Comparative Example 3 79.3 3.1 48.8 Comparative Example 4 70.6 4.0 43.3 Comparative Example 5 82.8 2.6 55.8 Comparative Example 6 83.6 2.8 54.7

[0112] It can be seen from Table 1 and Table 2 that compared with new asphalt, the penetration and ductility of waste aged asphalt are reduced, and the softening point is increased, indicating that asphalt tends to harden with the use of asphalt pavement. The regeneration agent of the present invention is used in Examples 1 to 3 to effectively regenerate waste aged asphalt and restore its viscoelasticity; and after the regenerated asphalt is aged in a film oven, a relatively high penetration and ductility remain, and the regenerated asphalt has good aging resistance.

[0113] In Comparative Example 1, polyaspartic acid ester intercalation modified montmorillonite is not added to the regeneration agent. The penetration and ductility of the regenerated asphalt after aging in the film oven are significantly reduced compared with those in Example 1, and the aging resistance of the regenerated asphalt is significantly reduced. In Comparative Example 2, when preparing polyaspartic acid ester intercalation modified montmorillonite, ethylenediamine is used instead of dodecanediamine in Example 1 to react with maleic acid ester. The penetration and ductility of the regenerated asphalt are reduced compared with those in Example 1, the softening point is increased, and the aging resistance of the regenerated asphalt is reduced. This may be due to the poor flexibility of the polyaspartic acid ester molecular chain prepared by ethylenediamine, which is difficult to enter the interlayer of montmorillonite, resulting in a decrease in the performance of the regenerated asphalt. In Comparative Example 3, dodecyl dimethyl ammonium chloride intercalation modified montmorillonite is used as a component in the regeneration agent. The intercalation agent cannot react with the isocyanate curing agent, and the various properties of the regenerated asphalt are also reduced compared with those in Example 1, indicating that the type of intercalation agent has a significant effect on the performance of the regenerated asphalt.

[0114] 2. Road performance test of recycled asphalt mixture

[0115] The road performance of the recycled asphalt mixtures obtained in the above examples and comparative examples was tested, and the results are shown in Table 3.

[0116] The water stability of each recycled asphalt mixture was tested using the method in JTG E20-2011 "Testing Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" to evaluate its water stability;

[0117] The dynamic stability test was conducted using the rutting test procedure in JTG E20-2011 "Test Procedure for Asphalt and Asphalt Mixtures in Highway Engineering"; the test size was 300mm*300mm*50mm plate specimen, the test temperature was 60℃, the wheel pressure load was 0.7MPa, and the repeated wheel pressure time was 60min;

[0118] The low-temperature crack resistance experiment was carried out using the asphalt mixture bending test procedure in JTG E20-2011 "Test Procedure for Asphalt and Asphalt Mixtures in Highway Engineering"; the specimen dimensions were 250 mm ± 2 mm in length, 30 mm ± 2 mm in width, 35 mm ± 2 mm in height, 200 mm ± 0.5 mm in span, the test temperature was -10 °C ± 0.5 °C, and the loading rate was 50 mm / min.

[0119] Table 3: Test results of road performance of recycled asphalt mixture.

[0120] Residual stability after immersion in water (%) Dynamic stability (times / mm) Maximum bending strain (με) Example 1 92.1 4211 3303.1 Example 2 88.7 4508 3276.2 Example 3 86.6 5187 3122.7 Comparative Example 1 89.8 4097 3238.1 Comparative Example 2 90.8 4088 3194.3 Comparative Example 3 91.3 4175 3238.5 Comparative Example 4 85.0 3607 2916.7 Comparative Example 5 91.2 4033 3038.2 Comparative Example 6 90.7 3849 3014.1

[0121] It can be seen from Table 3 that the water-residual stability of the regenerated asphalt mixtures prepared by using the regeneration agent of the present invention in Examples 1 to 3 is higher than ≥85% of the specification requirement, and the water stability meets the use requirements of high-grade asphalt pavement; the dynamic stability is higher than the requirement of 2800 times / mm, and the high-temperature rutting resistance meets the use requirements of hot summer areas; the maximum bending tensile strain is ≥3000με, and the low-temperature crack resistance meets the use requirements of cold winter areas.

[0122] Combining Table 1 and Table 3, it can be seen that in Comparative Example 4, polyaspartic acid ester is not added to the regeneration agent, and the regeneration ability of the regeneration agent for asphalt is reduced compared with that in Example 1, and the reinforcing effect of aspartic acid polyurea resin is lacking, and the water stability, high temperature rutting resistance and low temperature crack resistance of the regenerated asphalt mixture are significantly reduced compared with that in Example 1. In Comparative Example 5, polyaspartic acid ester is not modified by hydroxytyrosol, and polar aromatic groups are not introduced into its molecular chain. The compatibility of the regeneration agent with asphaltene in asphalt is reduced, which also leads to a decrease in the regeneration ability of the regeneration agent for aged asphalt, and the high temperature rutting resistance and low temperature crack resistance of the regenerated asphalt mixture are reduced compared with those in Example 1. In Comparative Example 6, ethylenediamine with a shorter molecular chain is used to react with modified maleic acid ester, and the non-polar chain of the obtained polyaspartic acid ester is too short, and the amphiphilic effect is reduced. The regeneration ability of the regeneration agent for aged asphalt is also reduced, and the high temperature rutting resistance and low temperature crack resistance of the obtained regenerated asphalt mixture are also reduced accordingly.

Claims

1. An anti-aging asphalt regeneration agent, characterized in that: It includes component A and component B; In parts by weight, component A includes: 10 to 12 parts of base oil, 6 to 8 parts of polyaspartic acid ester, and 3 to 5 parts of polyaspartic acid ester intercalated modified montmorillonite; component B includes an isocyanate curing agent; The preparation method of the polyaspartic acid ester intercalation modified montmorillonite comprises the following steps: (1) subjecting dimethyl maleate to a Michael addition reaction with a C12-C16 straight-chain aliphatic diamine to obtain an initial polyaspartic acid ester; the molar ratio of the straight-chain aliphatic diamine to dimethyl maleate is 1:2-2.4; (2) subjecting the initial polyaspartic acid ester to an ester exchange reaction with 2-hydroxypropyltrimethylammonium chloride to obtain a quaternary ammonium salt-modified polyaspartic acid ester; the molar ratio of 2-hydroxypropyltrimethylammonium chloride to the dimethyl maleate added in step (1) is 2 to 2.4:1; (3) adding quaternary ammonium salt-modified polyaspartic acid ester and sodium montmorillonite to water respectively, stirring evenly to obtain a quaternary ammonium salt-modified polyaspartic acid ester solution and a montmorillonite dispersion, mixing the quaternary ammonium salt-modified polyaspartic acid ester solution and the montmorillonite dispersion, stirring and reacting to obtain the polyaspartic acid ester intercalation modified montmorillonite; The mass ratio of quaternary ammonium salt modified polyaspartic acid ester to sodium montmorillonite is 7-8:10; the polyaspartic acid ester is modified by silane and hydroxytyrosol, and the preparation method thereof is as follows: (a) subjecting ethylene glycol monoallyl ether to a hydrosilylation reaction with triethoxysilane to obtain hydroxy-terminated triethoxysilane; the molar ratio of ethylene glycol monoallyl ether to triethoxysilane is 1:1 to 1.2; (b) firstly subjecting hydroxytyrosol to an ester exchange reaction with dimethyl maleate, and then adding the terminal hydroxy triethoxy silane obtained in step (a) to continue the ester exchange reaction to obtain a modified maleate; the molar ratio of hydroxytyrosol, terminal hydroxy triethoxy silane and dimethyl maleate is 1 to 2:2 to 3:2; (c) subjecting the modified maleate obtained in step (b) to a Michael addition reaction with a C6-C12 straight-chain aliphatic diamine to obtain the polyaspartic acid ester; the molar ratio of the straight-chain aliphatic diamine to the modified maleate is 1:2-2.

4.

2. The anti-aging asphalt regeneration agent according to claim 1, characterized in that: The reaction conditions of step (1) are as follows: a linear aliphatic diamine is mixed with dimethyl maleate, 200-500 ppm of sodium methoxide catalyst is added, and the mixture is reacted at 60-80° C. for 6-8 hours under nitrogen protection to obtain the initial polyaspartic acid ester.

3. The anti-aging asphalt regeneration agent according to claim 1, characterized in that: The reaction conditions of step (2) are as follows: the initial polyaspartic acid ester is mixed with a 2-hydroxypropyltrimethylammonium chloride solution, and 200 to 500 ppm of p-toluenesulfonic acid catalyst is added, and the mixture is stirred evenly and reacted at 130 to 150° C. for 4 to 6 hours, and the quaternary ammonium salt-modified polyaspartic acid ester is obtained after removing the solvent.

4. The anti-aging asphalt regeneration agent according to claim 1, characterized in that: Step (3) After mixing the quaternary ammonium salt modified polyaspartic acid ester solution and the montmorillonite dispersion, stirring and reacting at 60-80° C. for 2-4 hours, the polyaspartic acid ester intercalation modified montmorillonite is obtained.

5. The anti-aging asphalt regeneration agent according to claim 1, characterized in that: The base oil is an aromatic oil with an aromatic content of ≥75wt%.

6. The anti-aging asphalt regeneration agent according to claim 1, characterized in that: The mass ratio of component A to component B is 15:2-5.

7. A method for preparing a recycled asphalt mixture, characterized in that: The steps include: S1: milling the aged asphalt pavement to obtain waste asphalt mixture; S2: preheating and keeping the waste asphalt mixture, aggregate and new asphalt warm; S3: adding the anti-aging asphalt regeneration agent as described in any one of claims 1 to 6 to the preheated waste asphalt mixture and mixing; then adding the preheated aggregate and continuing to mix; then adding new asphalt and mineral powder in sequence, and mixing to obtain the regenerated asphalt mixture.

8. The method for preparing a regenerated asphalt mixture according to claim 7, characterized in that: In parts by weight, the addition amount of each component in S3 is: 300-500 parts of waste asphalt mixture, 400-600 parts of aggregate, 10-30 parts of new asphalt, and 50-200 parts of mineral powder; the added mass of the anti-aging asphalt regeneration agent is 8-12% of the mass of the waste asphalt mixture.

9. The method for preparing a recycled asphalt mixture according to claim 7, characterized in that: The preheating temperature of the waste asphalt mixture in S2 is 100-140°C, the preheating temperature of the aggregate is 170-210°C, and the preheating temperature of the new asphalt is 160-170°C; the mixing temperature in S3 is 175-185°C.