Regenerated asphalt composition, asphalt regeneration agent and use thereof

Abstract

The present invention provides a regenerated asphalt composition, an asphalt regeneration agent and uses thereof. Based on the total weight of the asphalt regeneration agent, the asphalt regeneration agent comprises 65wt% to 99.9wt% of a softener and 0.1wt% to 35wt% of a dispersant, wherein the softener is compatible with the soft asphaltene component in the aged asphalt, and the dispersant comprises a polar group that interacts with the asphaltene in the aged asphalt. The softener of the present invention is used as a diluent to soften the old asphalt and acts as a carrier of the dispersant; the dispersant can interact with the asphaltene to disperse and depolymerize the asphaltene, and the combination of the softener and the dispersant can restore the aged asphalt to a level close to the original performance.

Description

Technical Field

[0001] The invention belongs to the technical field of asphalt regeneration, and in particular relates to a regenerated asphalt composition, an asphalt regeneration agent and uses thereof. Background Art

[0002] Asphalt pavement is subjected to dynamic and static loads such as compressive stress, shear stress and tensile stress under the action of wheel loads. Asphalt pavement is exposed to the nature for a long time, and therefore is affected by various natural factors such as oxygen, sunlight, temperature, water and wind, which causes physical and chemical changes in the properties of asphalt and aggregate in the mixture, and ultimately manifests as increased viscosity, aging and refinement of asphalt in the asphalt mixture. When asphalt is affected by natural factors in the pavement, it will cause the asphalt components to "migrate", that is, the asphalt increases accordingly, which leads to asphalt aging and increased viscosity. As the viscosity increases, the penetration, elongation and softening point of asphalt will also change regularly, and at the same time, the asphalt performance will decrease.

[0003] The major challenge of recycling reclaimed asphalt pavement (RAP) is how to activate and restore the construction, workability and road performance of the old asphalt. At present, regenerated RAP (especially for high-mixed and deeply aged) usually requires adding a certain amount of regeneration agent according to the degree of aging of the old asphalt, replenishing the light components lost during the mixing construction and long-term service of the asphalt, improving the compatibility between the various components of the asphalt, diluting and dispersing the asphalt, and restoring the various properties of the old asphalt to the same level as the original asphalt.

[0004] Traditional asphalt regeneration agents are mainly based on petroleum or bio-oil refining and processing, with a high content of low-polarity light components. However, due to different raw materials, the chemical properties of their constituent molecules and the corresponding macroscopic regeneration effects vary greatly. Aromatic oil extracted from petroleum is similar to the aromatic components of asphalt in chemical composition, and shows good compatibility and aging resistance when used for regenerated asphalt. Paraffin and cycloparaffin oils extracted from petroleum are not compatible with asphalt. Oils, fatty acids, etc. extracted from animal and plant materials may cause insufficient durability of regenerated asphalt due to their own easy oxidation. Summary of the invention

[0005] The purpose of the present invention is to improve an asphalt regeneration agent obtained by compounding a softener and a dispersant for recycling road asphalt. The asphalt regeneration agent has both low viscosity and high fluidity, and can disperse and depolymerize asphaltene through effective interaction to restore the performance of aged asphalt.

[0006] In order to achieve the above-mentioned purpose, the present invention provides an asphalt regeneration agent, which comprises 65wt% to 99.9wt% of a softener and 0.1wt% to 35wt% of a dispersant, based on the total weight of the asphalt regeneration agent, wherein the softener is compatible with the soft asphalt component in the aged asphalt, and the dispersant includes a polar group that interacts with the asphaltene in the aged asphalt.

[0007] In a specific embodiment, the softener is aromatic oil, and the dispersant is hydrophobic ionic liquid or long-chain alkylphenol.

[0008] In a specific embodiment, the asphalt regeneration agent includes aromatic oil and hydrophobic ionic liquid. Based on the total weight of the asphalt regeneration agent, the content of the aromatic oil is 99.9wt% to 99.5wt%, and the content of the hydrophobic ionic liquid is 0.1wt% to 0.5wt%.

[0009] In a specific embodiment, the hydrophobic ionic liquid is an imidazolium ionic liquid, the number of carbon atoms on the imidazolium cation side chain is not less than 4, and the anion is one of a hexafluorophosphate ion and a bistrifluoromethylsulfonyl imide anion.

[0010] In a specific embodiment, the asphalt regeneration agent includes aromatic oil and long-chain alkylphenol. Based on the total weight of the asphalt regeneration agent, the aromatic oil content is 65wt% to 80wt%, and the long-chain alkylphenol content is 20wt% to 35wt%.

[0011] In a specific embodiment, the tail chain of the long-chain alkylphenol has 6 to 12 carbon atoms.

[0012] In a specific embodiment, the softener is cyclohexylbenzene, and the dispersant is 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid or dodecylphenol.

[0013] The present invention also provides a use of the asphalt regeneration agent described above for recycling road asphalt.

[0014] The present invention also provides a regenerated asphalt composition, comprising aged asphalt and the asphalt regeneration agent described above, wherein the content of the asphalt regeneration agent is 5 to 15 wt % based on the total weight of the aged asphalt.

[0015] In a specific embodiment, the regenerated asphalt composition is prepared by the following method, including: adding an asphalt regeneration agent at room temperature to aged asphalt in a melted state, and mixing the two under preset conditions to obtain regenerated asphalt, wherein the preset conditions include: shearing and stirring in a shearing machine for 30 minutes, a shearing temperature of 150°C-165°C, and a shear rate of 1500-2500rpm.

[0016] The beneficial effects of the present invention include at least:

[0017] 1. The asphalt regeneration agent provided by the present invention includes a softener and a dispersant. The softener has low viscosity, low polarity and high fluidity, does not significantly interact with asphaltene, and is used as a diluent to soften old asphalt, and at the same time acts as a carrier of the dispersant; the dispersant has a high polarity and molecular weight, and can interact with asphaltene to achieve the effect of destroying the stability of asphaltene associations and then depolymerizing them; in this way, the combination of softener and dispersant can improve the compatibility relationship between the various components of asphalt, disperse and depolymerize asphaltene, and restore the aged asphalt to near its original performance.

[0018] 2. The asphalt regeneration agent provided by the present invention is compounded by a softener and a dispersant. Compared with the asphalt regeneration agent in the prior art which is only composed of a softener, the amount of softener used is greatly reduced. Especially when the dispersant is a hydrophobic ionic liquid, only an extremely low dosage is required, which can greatly improve the economic and environmental benefits. At the same time, it also provides a more homogeneous colloidal structure on a microscopic scale, and the prepared asphalt composition has potentially superior long-term performance.

[0019] 3. The softener and dispersant in the asphalt regeneration agent provided by the present invention can be evenly stirred at room temperature. Compared with the asphalt regeneration agent in the prior art, the composition and preparation method are simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 (a) Rheological properties characterization (crossover frequency) corresponding to multiple experimental objects provided in Example 9;

[0021] Figure 1 (b) rheological properties characterization (GR parameters) corresponding to multiple experimental objects provided in Example 9;

[0022] Figure 2 Fatigue performance characterization corresponding to multiple experimental objects provided in Example 9;

[0023] Figure 3 Characterization of water loss performance corresponding to multiple experimental objects provided in Example 9;

[0024] FIG. 4( a) is absorbance data corresponding to infrared spectroscopy analysis of multiple experimental objects provided in Example 9;

[0025] FIG4( b ) is a functional group index in infrared spectrum analysis corresponding to multiple experimental objects provided in Example 9;

[0026] Figure 5 Molecular dynamics simulation system and model molecules corresponding to the composite regeneration of aromatic oil and ionic liquid;

[0027] Figure 6 is the asphaltene aggregation number and its average association size obtained by simulation. DETAILED DESCRIPTION

[0028] The present invention is described in detail below with reference to the accompanying drawings and embodiments, but the present invention can be implemented in many different ways as limited and covered by the claims.

[0029] The present invention mainly proposes a composition design method of asphalt regeneration agent from a molecular perspective, that is, preparing asphalt regeneration agent by doping a softener with a small amount of asphaltene dispersant. Specifically, the softener is composed of small molecules with low viscosity, low polarity, and compatibility with the soft asphaltene component in the asphalt. Such molecules have high fluidity but do not interact significantly with asphaltene. The role they play is essentially an asphaltene diluent, which is used to soften the old asphalt. At the same time, they act as a carrier of the dispersant, and use their own high fluidity to transport and distribute the dispersant in the old asphalt system. The dispersant contains polar groups (or large aromatic ring structures), which have relatively high polarity and molecular weight, and can interact significantly with asphaltene, thereby achieving the effect of destroying the stability of asphaltene associations and then depolymerizing them. The dispersant can improve the dispersibility of asphaltene and the homogeneity of the asphalt colloid structure, and also play an auxiliary softener effect to further soften the old asphalt.

[0030] Based on the above design method, the present invention provides an asphalt regeneration agent, which comprises 65wt% to 99.9wt% of a softener and 0.1wt% to 35wt% of a dispersant, based on the total weight of the asphalt regeneration agent, wherein the softener is compatible with the soft asphalt component in the aged asphalt, and the dispersant includes a polar group that interacts with the asphaltene in the aged asphalt.

[0031] In the present invention, the total content of the softener and the dispersant is 100%. In other embodiments, the asphalt regeneration agent may further include other conventional additives that do not affect the functions of the softener and the dispersant.

[0032] Preferably, the softener is aromatic oil, and more preferably, the softener is cyclohexylbenzene.

[0033] Aromatic oil is the main component of most petroleum-based regeneration agents at present, and can be used as a softener in the present invention. Cyclohexylbenzene, as a softener, has excellent chemical stability, low viscosity, high boiling point (240°C) and other characteristics. It is a common aromatic small molecule, and its molecular structure is similar to the aromatic components of asphalt, which can ensure compatibility with soft asphalt components. At the same time, because its molecular structure contains only one benzene ring and no polar groups, its dispersing effect on asphalt is weak and can be ignored, and it is suitable as a softener.

[0034] It should be noted that the softener of the present invention is not limited to cyclohexylbenzene, and other aromatic oils that meet the requirements of low viscosity, low polarity and high fluidity can be used.

[0035] Preferably, the dispersant is a hydrophobic ionic liquid or a long-chain alkylphenol.

[0036] More preferably, the hydrophobic ionic liquid is an imidazolium ionic liquid, the number of carbon atoms on the side chain of the imidazolium cation is not less than 4, and the anion is one of a hexafluorophosphate ion and a bistrifluoromethylsulfonyl imide anion.

[0037] More preferably, the dispersant is 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid.

[0038] 1-Butyl-3-methylimidazolium hexafluorophosphate ionic liquid (IL) is a hydrophobic room temperature ionic liquid of the imidazole class. Indoor experiments and simulation calculations show that it can effectively disperse asphaltene and depolymerize aggregates with the help of cation-π and other interaction forms. Generally speaking, the dispersion and depolymerization ability of ionic liquids increases with the increase of cation aromaticity, tail chain length and anion hydrophobicity, and it has great potential to solve the asphaltene aggregation problem in crude oil extraction and post-processing.

[0039] More preferably, the tail chain of the long-chain alkylphenol has 6 to 12 carbon atoms.

[0040] More preferably, the dispersant is dodecylphenol.

[0041] Dodecylphenol (DP) belongs to the family of amphiphilic molecules derived from alkylbenzenes. Its effect of dispersing and depolymerizing asphaltene is mainly controlled by the polarity of the head group (hydroxyl functional group) and the length of the alkyl tail chain. The stronger the polarity of the head group, the stronger the interaction with asphaltene through hydrogen bonds and other forms, while the longer the tail chain, the easier it is to hinder the aggregation of asphaltene in the form of steric hindrance.

[0042] Preferably, the asphalt regeneration agent comprises aromatic oil and hydrophobic ionic liquid. Based on the total weight of the asphalt regeneration agent, the content of the aromatic oil is 99.9wt% to 99.5wt%, and the content of the hydrophobic ionic liquid is 0.1wt% to 0.5wt%, wherein the hydrophobic ionic liquid is an imidazole ionic liquid, the number of carbon atoms on the imidazole cation side chain is not less than 4, and the anion is one of a hexafluorophosphate ion and a bistrifluoromethylsulfonyl imide anion.

[0043] More preferably, the asphalt regeneration agent includes cyclohexylbenzene and 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid. Based on the total weight of the asphalt regeneration agent, the cyclohexylbenzene content is 99.7wt%, and the 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid content is 0.03wt%.

[0044] Preferably, the asphalt regeneration agent comprises aromatic oil and long-chain alkylphenol. Based on the total weight of the asphalt regeneration agent, the content of the aromatic oil is 65wt% to 80wt%, and the content of the long-chain alkylphenol is 20wt% to 35wt%, wherein the number of carbon atoms in the tail chain of the long-chain alkylphenol is 6 to 12.

[0045] More preferably, the asphalt regeneration agent comprises cyclohexylbenzene and dodecylphenol. Based on the total weight of the asphalt regeneration agent being 100wt%, the content of the cyclohexylbenzene is 72.5wt%, and the content of the dodecylphenol is 27.5wt%.

[0046] The softener in the asphalt regeneration agent provided by the present invention realizes the softening of the material on a macro scale, and the dispersant realizes the depolymerization and dispersion of the asphaltene association on a micro scale, that is, the performance of the aged asphalt is restored by compounding the softener and the dispersant.

[0047] The preparation method of the asphalt regeneration agent provided by the present invention comprises: stirring a softener and a dispersant evenly at room temperature.

[0048] The present invention also provides use of the above-mentioned asphalt rejuvenating agent for recycling road asphalt.

[0049] That is, by adding the asphalt regeneration agent mentioned above to road asphalt, the performance of the road asphalt can be restored, and the recovered asphalt composition can be used again.

[0050] The present invention also provides a regenerated asphalt composition, comprising aged asphalt and the asphalt regeneration agent described above, wherein the content of the asphalt regeneration agent is 5 to 15 wt % based on the total weight of the aged asphalt.

[0051] That is, the asphalt regeneration agent is added to the aged asphalt in an amount of 5 to 15 wt %. When the total mass of the aged asphalt is 100 grams, the added amount of the asphalt regeneration agent is 5 to 15 grams.

[0052] Preferably, the regenerated asphalt composition comprises aged asphalt and an asphalt regeneration agent composed of aromatic oil and hydrophobic ionic liquid, and the content of the asphalt regeneration agent is 5-10wt% based on the total weight of the aged asphalt.

[0053] Preferably, the regenerated asphalt composition comprises aged asphalt and an asphalt regeneration agent composed of aromatic oil and long-chain alkylphenol, and the content of the asphalt regeneration agent is 9-15wt% based on the total weight of the aged asphalt.

[0054] It is understandable that due to the different aging degrees of aged asphalt, the amount of asphalt regeneration agent added will also be different. Technical personnel in this field can obtain the optimal amount of asphalt regeneration agent added through experiments. However, as long as an appropriate amount of asphalt regeneration agent is added, the performance of aged asphalt can be improved. Asphalt compositions with different contents of asphalt regeneration agent can be recycled and reused.

[0055] Preferably, the regenerated asphalt composition is prepared by the following method, comprising: adding an asphalt regeneration agent at room temperature to aged asphalt in a melted state, and mixing the two under preset conditions to obtain a regenerated asphalt composition, wherein the preset conditions include: shearing and stirring in a shearing machine for 30 minutes, a shearing temperature of 150°C-165°C, and a shear rate of 1500-2500rpm.

[0056] In a specific embodiment, No. 70 petroleum asphalt was selected and treated indoors by a standard pressure aging vessel (PAV) method for 40 hours to prepare aged asphalt. Three strategies were used for its regeneration for comparative study, one of which was to use only aromatic oil cyclohexylbenzene (to prepare traditional regenerated asphalt), and the other two were to use aromatic oil doped with hydrophobic ionic liquid and long-chain alkylphenol as asphalt regeneration agents.

[0057] At the same time, for the combination of aromatic oil + hydrophobic ionic liquid and the combination of aromatic oil + long-chain alkylphenol, the optimal dosage is first determined by matching the high-temperature performance grade of the original asphalt, and then the regeneration effect of the optimal dosage is demonstrated, including viscoelastic rheology, fatigue and water loss performance tests, infrared spectroscopy analysis, and molecular dynamics simulation.

[0058] Embodiment 1 to Embodiment 4

[0059] The optimal dosage of hydrophobic ionic liquid is determined by matching the high temperature performance grade of the original asphalt.

[0060] The high-temperature PG (high-temperature performance grade) of No. 70 petroleum asphalt in its original state is 66.8℃.

[0061] Example 1

[0062] Step 1: prepare aged asphalt. Treat No. 70 petroleum asphalt by the standard method of indoor pressure aging container (PAV) for 40 hours to obtain 200 grams of aged asphalt, and heat it to 150°C-165°C to melt it to obtain aged asphalt in a melted state.

[0063] Step 2: Prepare an asphalt regeneration agent by stirring 20 grams of cyclohexylbenzene and 0.0514 grams of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid at room temperature to obtain 20.0514 grams of asphalt regeneration agent.

[0064] Step three: add 20.0514 grams of asphalt regeneration agent at room temperature to 200 grams of melted aged asphalt, shear and stir in a shearing machine for 30 minutes, the shear temperature is 150°C-165°C, the shear rate is 1500-2500rpm, and the obtained regenerated asphalt composition is expressed as PAV40+10%CHB+0.0257%IL.

[0065] The high-temperature PG corresponding to the regenerated asphalt composition prepared in Example 1 is 65.0°C.

[0066] Example 2

[0067] Example 2 is basically the same as Example 1, the only difference is that the asphalt regeneration agent added in step 2 is different. The mass of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid in the asphalt regeneration agent added in Example 1 is 0.0514 grams, while the mass of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid in the asphalt regeneration agent added in Example 2 is 0.0542 grams. The obtained regenerated asphalt composition is expressed as PAV40+10% CHB+0.0271% IL.

[0068] The high-temperature PG corresponding to the regenerated asphalt composition prepared in Example 2 is 66.8°C.

[0069] Example 3

[0070] Example 2 is basically the same as Example 1, the only difference is that the asphalt regeneration agent added in step 2 is different. The mass of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid in the asphalt regeneration agent added in Example 1 is 0.0514 grams, while the mass of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid in the asphalt regeneration agent added in Example 3 is 0.0566 grams. The obtained regenerated asphalt composition is expressed as PAV40+10% CHB+0.0283% IL.

[0071] The high-temperature PG corresponding to the regenerated asphalt composition prepared in Example 2 is 68.5°C.

[0072] Example 4

[0073] Example 4 is basically the same as Example 1, the only difference is that the asphalt regeneration agent added in step 2 is different. The mass of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid in the asphalt regeneration agent added in Example 1 is 0.0514 grams, while the mass of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid in the asphalt regeneration agent added in Example 4 is 0 grams. The obtained regenerated asphalt composition is expressed as PAV40+10% CHB.

[0074] The high-temperature PG corresponding to the regenerated asphalt composition prepared in Example 4 is 82.3°C.

[0075] By comparing the experimental results of Examples 1 to 4, it can be seen that the high-temperature PG corresponding to the asphalt regeneration agent without the addition of liquid (1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid) is the highest. Adding a small amount of ionic liquid can reduce the high-temperature PG of the asphalt composition. For 200 grams of aged asphalt and when the cyclohexylbenzene in the asphalt regeneration agent is fixed at 20 grams, the optimal amount of ionic liquid added is 0.0542 grams. At this time, the corresponding high-temperature PG is the same as the high-temperature PG of the original state of the asphalt, that is, the optimal dosage corresponding to PAV40 is 10% CHB+0.0271% IL.

[0076] Embodiment 5 to Embodiment 8

[0077] Determining the optimal dosage of long-chain alkylphenol by matching the high-temperature performance grading of the original asphalt

[0078] The high-temperature PG (high-temperature performance grade) of No. 70 petroleum asphalt in its original state is 66.8℃.

[0079] Example 5

[0080] Step 1: prepare aged asphalt. Treat No. 70 petroleum asphalt by the standard method of indoor pressure aging container (PAV) for 40 hours to obtain 200 grams of aged asphalt, and heat it to 150°C-165°C to melt it to obtain aged asphalt in a melted state.

[0081] Step 2: Prepare an asphalt regeneration agent by mixing 20 grams of cyclohexylbenzene and 7 grams of dodecylphenol at room temperature to obtain 20.7 grams of asphalt regeneration agent.

[0082] Step three: add 27 grams of asphalt regeneration agent at room temperature to 200 grams of melted aged asphalt, shear and stir in a shearing machine for 30 minutes, the shear temperature is 150°C-165°C, the shear rate is 1500-2500rpm, and the obtained regenerated asphalt composition is expressed as PAV40+10%CHB+3.5%DP.

[0083] The high-temperature PG corresponding to the regenerated asphalt composition prepared in Example 1 is 69.7°C.

[0084] Example 6

[0085] Example 6 is basically the same as Example 5, the only difference is that the asphalt regeneration agent added in step 2 is different. The mass of dodecylphenol in the asphalt regeneration agent added in Example 5 is 7 grams, while the mass of dodecylphenol in the asphalt regeneration agent added in Example 6 is 7.6 grams. The obtained regenerated asphalt composition is expressed as PAV40+10%CHB+3.8%DP.

[0086] The high-temperature PG corresponding to the regenerated asphalt composition prepared in Example 6 is 66.6°C.

[0087] Example 7

[0088] Example 7 is basically the same as Example 5, the only difference is that the asphalt regeneration agent added in step 2 is different. The mass of dodecylphenol in the asphalt regeneration agent added in Example 5 is 7 grams, while the mass of dodecylphenol in the asphalt regeneration agent added in Example 7 is 8 grams. The obtained regenerated asphalt composition is expressed as PAV40+10%CHB+4.0%DP.

[0089] The high-temperature PG corresponding to the regenerated asphalt composition prepared in Example 6 is 64.1°C.

[0090] Example 8

[0091] Example 8 is basically the same as Example 5, the only difference is that the asphalt regeneration agent added in step 2 is different. The mass of dodecylphenol in the asphalt regeneration agent added in Example 1 is 7 grams, while the mass of dodecylphenol in the asphalt regeneration agent added in Example 8 is 0 grams. The obtained regenerated asphalt composition is expressed as PAV40+10% CHB.

[0092] The high-temperature PG corresponding to the regenerated asphalt composition prepared in Example 8 is 82.3°C.

[0093] By comparing the experimental results of Examples 5 to 8, it can be seen that the high-temperature PG corresponding to the asphalt composition without the addition of dodecylphenol is the highest. Adding a certain amount of dodecylphenol can reduce the high-temperature PG of the regenerated asphalt composition. When 200 grams of aged asphalt and cyclohexylbenzene in the asphalt regeneration agent is fixed at 20 grams, the optimal addition amount of dodecylphenol is 7.6 grams. At this time, the corresponding high-temperature PG is 66.6°C, which is closest to the high-temperature PG in the original state, that is, the optimal dosage corresponding to PAV40 is 10% CHB+3.8% DP.

[0094] It should be noted that the percentages of CHB, IL and DP specified in Examples 1 to 8 are all mass percentages, and the total mass of the aged asphalt is 100%. For ease of understanding, for example, PAV40+10% CHB+0.0.027% IL means that the asphalt aging time is 40h, and 10g CHB and 0.027g IL are added to every 100g PAV40.

[0095] Example 9

[0096] Comparison of the regeneration effects of the regenerated asphalt compositions obtained by adding different regeneration agents

[0097] Example 9 The performance of the original sample (unaged asphalt), aged asphalt, and IL aromatic oil composite regeneration, DP aromatic oil composite regeneration and aromatic oil regenerated asphalt composition were tested respectively. Specifically, the IL aromatic oil composite regeneration asphalt composition consisted of 200 grams of aged asphalt, 20 grams of cyclohexylbenzene and 0.054 grams of ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid); the DP aromatic oil composite regeneration asphalt composition consisted of 200 grams of aged asphalt, 20 grams of cyclohexylbenzene and 7.6 grams of dodecylphenol; the aromatic oil regeneration asphalt composition consisted of 200 grams of aged asphalt and 38 grams of cyclohexylbenzene.

[0098] (1) Viscoelasticity and fatigue characterization

[0099] Viscoelasticity and fatigue characterization are mainly based on dynamic shear rheometer (DSR), linear viscoelasticity theory and viscoelastic continuous damage model. First, a multi-temperature frequency sweep test was carried out on each asphalt sample. The frequency sweep range was 0.1 to 100 rad / s, the temperature range was about 0°C to 60°C (depending on the high temperature viscosity of different materials), and the strain amplitude was controlled at 0.1%. The obtained test data were processed based on the time-temperature equivalence principle to obtain the shear modulus and phase angle master curves at a reference temperature of 20°C, which were used to further obtain the crossover frequency and GR (Glover-Rowe) parameters. The crossover frequency is defined as the reduced angular frequency corresponding to the phase angle equal to 45°, which is an indicator of the overall hardness and consistency of asphalt. The GR parameter is widely used to evaluate the crack resistance of asphalt binders, is closely related to the ductility index, and can be calculated by the following formula:

[0100] GR=|G * |cos 2 δ / sinδ

[0101] Where |G*| is the modulus of the complex shear modulus, and δ represents the phase angle, both of which are obtained at 15°C and 0.005 rad / s. The fatigue characterization adopts a linear amplitude sweep test, that is, at 20°C and 10Hz, the asphalt sample is continuously cyclically loaded for 300s, 600s, and 900s, during which the strain amplitude increases linearly from 0.1% to 30%. The data analysis is based on the more mature viscoelastic continuous damage model system in the literature, and the fatigue envelope (the corresponding relationship between fatigue life and strain level) is obtained to evaluate the fatigue performance.

[0102] See also Figure 1 and Figure 2 , Figure 1 (a) is the cross-frequency diagram for rheological properties characterization, Figure 1 (b) is the GR parameter diagram for rheological properties characterization. Figure 2 Fatigue performance characterization results. Figure 1 The corresponding experimental data are shown in Table 1:

[0103] Table 1 Crossover frequencies and GR parameters corresponding to different experimental objects

[0104] Serial number Experimental subjects Crossover frequency (rad / s) GR parameter (Pa) 1 As is 290 725 2 Aged asphalt 0.33 370454 3 IL sesame oil compound regeneration 148.35 834 4 DP aromatic oil composite regeneration 175.43 583 5 Fragrance oil regeneration 138.16 680

[0105] Figure 1 The results of the frequency sweep test are shown. Figure 1 It can be seen that the aging treatment significantly increased the hardness of the original asphalt and reduced its crack resistance, while the three asphalt regeneration agents used effectively reversed the adverse effects of aging, and the overall regeneration effect was similar. Figure 2 The results of fatigue performance characterization based on linear amplitude sweep test are shown. It can be seen from the relative positions of the envelopes shown that the three asphalt regeneration agents significantly improved the fatigue crack resistance of aged asphalt, and the fatigue life of the resulting regenerated asphalt composition was even better than that of the original asphalt at a given strain level.

[0106] (2) Water loss performance evaluation

[0107] The water damage performance was evaluated by asphalt pulling test. A 0.2mm thick asphalt film was placed between a 70mm diameter limestone specimen and a 50mm diameter pulling head. The reference group was left at room temperature for 48 hours, and the experimental group was placed in a 60℃ constant temperature water bath for 48 hours and then cooled in a 20℃ room temperature environment for 2 hours. The test temperature was 20℃, the pulling rate was controlled at 0.7MPa / s, and the retention rate of the pulling strength after immersion in water was used as the water damage index to evaluate the asphalt's water damage resistance.

[0108] Water loss performance evaluation results are as follows Figure 3 As shown, Figure 3 The corresponding experimental data are shown in Table 2.

[0109] Table 2 Water damage index corresponding to different experimental objects

[0110] Serial number Experimental subjects Water Damage Index MDI 1 As is 0.79 2 Aged asphalt 0.55 3 IL sesame oil compound regeneration 0.79 4 DP aromatic oil composite regeneration 0.72 5 Fragrance oil regeneration 0.76

[0111] based on Figure 3 From the water damage index in Table 2, it can be seen that the retention rate of the adhesion strength between asphalt and stone interface decreases significantly after aging. The three regeneration methods can effectively restore the water loss performance to the same level as the original asphalt. Among them, the regeneration effect of ionic liquid combined with aromatic oil at extremely low dosage is slightly better than the other two regeneration agents.

[0112] (3) Infrared spectrum analysis results

[0113] Fourier transform infrared spectroscopy was used to investigate the concentration changes of characteristic functional groups before and after regeneration. The asphalt film was prepared by potassium bromide tableting method with a scanning wavenumber range of 4000 to 500 cm -1 , resolution 4cm -1 Each sample was scanned 16 times using the area method at 1330 cm -1 Up to 1490cm -1 The vibration peak of the interval was used as a reference to calculate the carbonyl index and sulfoxide index.

[0114] The infrared spectrum analysis structure is shown in Figure 4. In Figure 4(a), compared with the original asphalt, the aging asphalt at 1700cm -1 A new characteristic peak is introduced at , corresponding to the carbonyl functional group, which is in line with expectations. Compared with the spectrum of aged asphalt, the three regenerated asphalt compositions do not show obvious new characteristic peaks, indicating that all reagents used do not react chemically with asphalt, and regeneration is achieved only through physical mixing. Figure 4 (b) Carbonyl and sulfoxide indexes of all asphalt materials. It can be seen that aging increases the concentration of the two functional groups in the asphalt system, which is attributed to the volatilization and polymerization of light components and the introduction of polar oxygen-containing functional groups. The three regeneration methods have different degrees of reduction in both indexes, and the effect is consistent with the total dose of the regeneration agent, that is, the more the total dosage, the more significant the reduction effect on the two indexes, which is derived from the dilution effect of the two polar groups after the addition of the regeneration agent. Because the additives investigated in this embodiment do not contain carbonyl and sulfoxide groups, but have methyl and methylene groups that have a reducing effect on the functional group index, and considering that it is a physical regeneration, when interpreting the infrared spectrum quantitative analysis data with external additives, it is clear that the reduction in the functional group index is due to its dilution and reduced concentration. The composition of asphalt changes after regeneration, so that the carbonyl and sulfoxide indices are no longer strongly correlated with its macroscopic properties. Therefore, Figure 4(b) cannot be simply used to compare the regeneration effects.

[0115] The experimental results corresponding to Figure 4(b) are shown in Table 3.

[0116] Table 3 Carbonyl and sulfoxide indexes corresponding to different experimental objects

[0117] Serial number Experimental subjects Hydroxyl Index Sulfoxide Index sum 1 As is 0.11 0.39 0.50 2 Aged asphalt 0.40 0.63 1.03 3 IL sesame oil compound regeneration 0.25 0.59 0.83 4 DP aromatic oil composite regeneration 0.18 0.57 0.75 5 Fragrance oil regeneration 0.17 0.48 0.65

[0118] (4) Molecular dynamics simulation results

[0119] Molecular dynamics simulation is used to investigate the mechanism and effectiveness of different dispersants in depolymerizing and dispersing asphaltene at the molecular scale. Gromacs software (version 2022.4) is used in combination with the OPLS-AA force field. The reference group contains two molecular systems, one is 40 asphaltene molecules and 2500 aromatic oil molecules, which is used to investigate the aggregation behavior of asphaltene in aromatic oil; the other is to add 40 colloid molecules to the former to investigate the dispersing effect of colloid on asphaltene. The experimental group contains two systems, namely, 8 ionic liquids and 8 alkylphenol molecules are added to the second reference system. The initial cubic box has a side length of 11.5nm. The equilibrium process uses 2ns annealing in the temperature range of 300K to 800K (NVT ensemble), and 7ns dynamic simulation at 298K and atmospheric pressure to achieve the balance of system density and energy (NPT ensemble), which produces a phase with a temperature of 298K and a long-term dynamic simulation of 50ns under the NVT ensemble. Data are collected every 10ps and combined into trajectories for subsequent analysis. The obtained molecular system (after equilibrium) and the model molecule used in the simulation are as follows Figure 5 As shown (taking the composite regeneration of ionic liquid and aromatic oil as an example). The aggregation number is calculated for the obtained trajectory, as shown in the following formula:

[0120]

[0121] In the formula, g i is the clustering number, n i Indicates that it contains g i The aggregation number is the number of associations of asphaltene monomers. The aggregation number is between 1 and the total number of asphaltene molecules. A larger value means a higher degree of aggregation (1 means all asphaltene is well dispersed without any aggregation; g z When it is equal to the total number of asphaltene molecules, it indicates that all asphaltene has aggregated into a single large association). In addition, trajectory processing also obtains the average association size, that is, the average number of asphaltene molecules contained in the association.

[0122] See also Figure 6 , Figure 6 Shown are the asphaltene aggregation number and average association size results obtained from molecular dynamics simulation. Figure 6The corresponding molecular dynamics simulation results are as follows: the aggregation number of asphaltene is 22.5, and the average size of the association body is 9.3; the aggregation number of asphaltene + colloid is 22.5, and the average size of the association body is 9.3; the aggregation number of asphaltene + colloid + IL is 4.4, and the average size of the association body is 2.7; the aggregation number of asphaltene + colloid + DP is 3.7, and the average size of the association body is 2.4. Figure 6 It can be seen that the aggregation behavior of asphalt in the aromatic oil environment is very obvious. The presence of colloid has a significant dispersing effect on asphaltenes. On this basis, a small amount of ionic liquid and alkylphenol are added. Both types of dispersants show the effect of synergistically dispersing and depolymerizing asphaltenes with colloids and reducing their aggregation degree, and the efficacy of ionic liquids is slightly better than that of alkylphenols.

[0123] From the regeneration effect of Example 9, it can be seen that the regeneration agent obtained by mixing aromatic oil with a small amount of asphalt dispersant can effectively restore multiple macroscopic properties of old asphalt. The effect is similar to that of traditional aromatic oil, but the required dosage is greatly reduced, especially when more environmentally friendly ionic liquids are used as dispersants, only extremely low dosages are required. The resulting high regeneration efficiency can greatly improve economic and environmental benefits, while also providing a more homogeneous colloidal structure on a microscopic scale. The resulting regenerated asphalt has potentially superior long-term performance.

[0124] The present invention uses a softener as a continuous phase and is doped with a small amount of asphaltene dispersant. The resulting composite regeneration agent should have the characteristics of low viscosity, high fluidity, and the ability to disperse and depolymerize asphaltene through effective interaction. In the embodiment, the softener is represented by a aromatic oil cyclohexylbenzene, but is not limited to cyclohexylbenzene or aromatic oil; the dispersant is represented by 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid and dodecylphenol, but is not limited to these two. Other reagents that meet the similar molecular characteristics described in the article can be used for the compounding of asphalt regeneration agents.

[0125] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions and substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A regenerated asphalt composition, characterized in that: Comprising aged asphalt and an asphalt rejuvenator, based on the total weight of the asphalt rejuvenator, the asphalt rejuvenator is composed of 99.9wt% to 99.5wt% of cyclohexylbenzene and 0.1wt% to 0.5wt% of a hydrophobic ionic liquid or is composed of 65wt% to 80wt% of cyclohexylbenzene and 20wt% to 35wt% of a long-chain alkylphenol, the hydrophobic ionic liquid is an imidazole ionic liquid, and the tail chain carbon number of the long-chain alkylphenol is 6 to 12, wherein, when the asphalt rejuvenator is composed of cyclohexylbenzene and the hydrophobic ionic liquid, the addition amount of the asphalt rejuvenator is 5% to 10% of the total weight of the aged asphalt, and when the asphalt rejuvenator is composed of cyclohexylbenzene and a long-chain alkylphenol, the addition amount of the asphalt rejuvenator is 9% to 15% of the total weight of the aged asphalt; The high temperature PG grade of the regenerated asphalt composition is the same as the high temperature PG grade of the original asphalt corresponding to the aged asphalt.

2. The regenerated asphalt composition according to claim 1, characterized in that: The regenerated asphalt composition is prepared by the following method, including: adding an asphalt regeneration agent at room temperature to aged asphalt in a melted state, and mixing the two under preset conditions to obtain a regenerated asphalt composition, wherein the preset conditions include: shearing and stirring in a shearing machine for 30 minutes, a shearing temperature of 150°C-165°C, and a shear rate of 1500-2500 rpm.

3. The regenerated asphalt composition according to claim 1, characterized in that: The number of carbon atoms on the side chain of the imidazolium cation of the hydrophobic ionic liquid is not less than 4, and the anion is one of a hexafluorophosphate ion and a bistrifluoromethylsulfonyl imide anion.

4. The regenerated asphalt composition according to claim 3, characterized in that: The hydrophobic ionic liquid is 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid.

5. The regenerated asphalt composition according to claim 1, characterized in that: The long-chain alkylphenol is dodecylphenol.

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