An aging sbs modified asphalt regenerant, and a preparation method and application thereof
By generating a regenerator with a monoisocyanate structure, the problem of repairing the degraded SBS structure in aged SBS modified asphalt was solved, the high-temperature and low-temperature performance of recycled asphalt was improved, and an environmentally friendly recycling effect was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHANGAN UNIV
- Filing Date
- 2026-04-29
- Publication Date
- 2026-06-02
AI Technical Summary
Existing technologies cannot effectively repair the degraded SBS structure in aged SBS-modified asphalt, leading to increased construction costs and environmental pollution. Furthermore, traditional diisocyanate compounds have problems such as high toxicity and poor low-temperature performance.
A regenerator based on the reaction of diisocyanate compounds and primary amine compounds to generate a monoisocyanate structure was developed. By controlling the reaction at low temperature, components A and B were prepared for the regeneration of aged SBS modified asphalt, thereby improving its high-temperature performance and low-temperature crack resistance.
It effectively restores various properties of aged SBS modified asphalt, improves environmental benefits and construction safety, and the performance of the recycled asphalt even exceeds that of the original asphalt, realizing efficient recycling and resource utilization of aged SBS modified asphalt.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of road engineering, specifically to an aged SBS modified asphalt rejuvenator, its preparation method, and its application. Background Technology
[0002] SBS modified asphalt was widely used in highway construction in the early days. However, with increasing service life, these roads face problems such as insufficient strength, rutting, and cracking, requiring repaving. This undoubtedly generates a large amount of waste asphalt mixture, leading to substantial costs due to waste accumulation, and improper disposal of this waste poses a significant environmental hazard. Through in-depth research and extensive testing of current asphalt recycling agents, it is concluded that the asphalt recycling process must consider not only the aging of the base asphalt caused by long-term ultraviolet radiation, oxygen, and environmental factors, but also the performance degradation caused by the degraded SBS modifier in aged SBS modified asphalt. Traditional recycling agents can only restore the performance of the base asphalt in aged SBS modified asphalt, but cannot effectively repair the degraded SBS structure.
[0003] Some scholars have focused on combining new SBS modifiers with lightweight components for the recycling of aged SBS-modified asphalt. While this method effectively replenishes the degraded SBS, it neglects the degraded SBS modifiers already present in the aged SBS-modified asphalt. This not only increases construction costs but also fails to fully utilize solid waste resources. Furthermore, it remains unknown whether the degraded SBS in the aged SBS-modified asphalt will interact with the new SBS modifiers.
[0004] Isocyanate groups can react with degraded SBS, repairing the degraded SBS modifier, reforming the spatial network structure of SBS, and restoring the properties of aged SBS-modified asphalt. Some researchers have used 4,4-diisocyanate dicyclohexylmethane (HMDI) to effectively repair degraded SBS, and a composite regenerator composed of traditional regenerators effectively restored the properties of aged SBS-modified asphalt. However, HMDI has the disadvantages of high toxicity and volatility, making it unsuitable for practical engineering applications. Furthermore, the high-strength characteristics of the cycloalkane inert groups of HMDI lead to poor low-temperature performance of the recycled asphalt, with deficiencies in crack resistance, stress relaxation properties, and ductility at low temperatures.
[0005] Therefore, how to repair degraded SBS modifiers by utilizing diisocyanate compounds while addressing their inability to be applied in practical engineering, and how to develop a regenerator that can comprehensively improve the high-temperature performance, elasticity, stability, and low-temperature crack resistance of aged SBS modified asphalt, has become a key requirement for breaking through existing technological bottlenecks. Summary of the Invention
[0006] One objective of this invention is to provide a novel regenerator based on diisocyanate compounds for the regeneration of aged SBS-modified asphalt. This overcomes the limitation of diisocyanate compounds in practical engineering applications, improving environmental benefits and construction safety. Furthermore, it enables efficient regeneration of aged SBS-modified asphalt and enhances some properties of the regenerated asphalt, allowing it to meet road use requirements and thus significantly reducing road construction costs.
[0007] A second objective of this invention is to provide a method for preparing a rejuvenator for aged SBS modified asphalt based on diisocyanate compounds. The rejuvenator prepared using this method achieves diverse restoration of the properties of aged SBS modified asphalt, and effectively restores the high-temperature and low-temperature resistance of the aged SBS modified asphalt.
[0008] A third objective of this invention is to provide a method for applying a regenerator for aged SBS-modified asphalt based on diisocyanate compounds. The asphalt regenerated using this method exhibits better overall performance, even exceeding that of the original asphalt, thus achieving the recycling of aged SBS-modified asphalt.
[0009] The first aspect of this invention discloses an aged SBS modified asphalt rejuvenator, comprising component A and component B. Component A, by mass fraction, comprises: 2.2-2.64 parts of diisocyanate compound, 1-1.2 parts of primary amine compound, and 0.1 parts of stabilizer; the diisocyanate compound and primary amine compound can react to generate a monoisocyanate compound. Component B comprises light oil components, and components A and B are used in combination.
[0010] Furthermore, component A also includes 1.5-1.8 parts of solvent, which is prepared by mixing primary amine compounds with solvent and stabilizer in sequence at a stable reaction temperature, then adding diisocyanate compounds dropwise at a medium speed and stirring until homogeneous, and finally distilling the solvent after restoring to room temperature.
[0011] Furthermore, the mass ratio of the diisocyanate compound to the primary amine compound is 2.2:1.
[0012] Furthermore, the solvent is at least one of dichloromethane, toluene, and tetrahydrofuran.
[0013] Further, the diisocyanate compound is at least one selected from 4,4-diisocyanate dicyclohexylmethane, toluene diisocyanate, and 4,4'-diphenylmethane diisocyanate.
[0014] Furthermore, the primary amine compound is a methoxyaniline compound, specifically including at least one of 4-methoxyaniline, 2-methoxy-5-methylaniline, or ethoxyaniline.
[0015] Furthermore, the stabilizer is at least one of acetone and acetylacetone.
[0016] Furthermore, the light oil is divided into at least one of aromatic oil, soybean oil, and catalytic cracking oil.
[0017] The second aspect of this invention discloses a method for preparing an aged SBS modified asphalt recycling agent, comprising the following steps: S1. Maintain the system temperature at 5℃, then add the primary amine compound to the solvent and mix evenly to obtain a primary amine-solvent mixed solution.
[0018] S2. Add the stabilizer evenly to the mixed solution of S1, and maintain the mixing temperature at 5℃ to obtain a dark brown liquid.
[0019] S3. The diisocyanate compound is added uniformly to the dark brown liquid obtained in S2 at a dropping rate of 0.5 ml / min. The reaction is stirred continuously until the diisocyanate compound is completely added. After the reaction is completed, the mixture is allowed to stand for 1 hour. Then, it is distilled under reduced pressure at 39°C to remove the residual solvent in the system, and a white emulsion-like regenerator component A is obtained for later use.
[0020] S4. Store component A in a sealed brown reagent bottle, and store it separately from component B (light oil) at room temperature, away from moisture and light. When needed, prepare the mixture according to the specified ratio for the regeneration of aged SBS modified bitumen materials.
[0021] In the preparation of regenerants, reaction temperature and reaction rate are key factors affecting the yield of the target product. The two ends of diisocyanate compounds readily react with the phenylamino group in primary amine compounds, leading to the formation of byproducts.
[0022] The third aspect of this invention discloses the application of aged SBS modified asphalt recycler in the recycling of waste asphalt. When preparing recycled asphalt, the aged SBS modified asphalt is heated to a fluid state, and then 4% of the asphalt mass of recycler component B is added at a stirring temperature of 150°C, and stirred continuously at a speed of 800 rpm for 10 minutes; then 0.5% to 1.5% of the asphalt mass of recycler component A is added, and stirred continuously at a speed of 800 rpm for 15 minutes before use.
[0023] Preferably, the amount of the regenerator component A is 1% of the asphalt mass. Beneficial effects
[0024] (1) The regenerator provided by this invention includes component A and component B. Component B is a light oil, which can soften aged SBS modified asphalt and effectively restore the viscosity and ductility of aged base asphalt. Component A uses diisocyanate compounds and primary amine compounds as raw materials. Due to the high mechanical properties of the dicycloalkane structure, the stable scaffold effect formed by the diisocyanate compound inhibits the movement of molecular chains, thus deteriorating its low-temperature performance. In this invention, functional groups such as methoxy and urea groups, which are beneficial to low-temperature performance, are introduced through the reaction of primary amine compounds and diisocyanate compounds, resulting in a monoisocyanate structure. Monoisocyanate compounds differ from diisocyanate compounds in their repair mechanism. Monoisocyanate compounds reconstruct the structure of degraded SBS by unilaterally extending the chain, resulting in a more complex spatial network structure after SBS repair. Compared with diisocyanates, the monoisocyanate regenerator proposed in this invention can more comprehensively restore the performance of aged SBS modified asphalt, improve asphalt elasticity, and achieve improved low-temperature performance of regenerated asphalt. The recycler provided by this invention improves the safety and environmental benefits of recycler use, effectively restores the high-temperature and low-temperature resistance of recycled asphalt, and achieves diverse restoration of the properties of aged SBS modified asphalt; it also effectively treats hazardous chemicals such as methoxyaniline, reducing environmental harm.
[0025] (2) In the preparation process of the regenerant provided by this invention, the main reaction is that a compound of methoxyaniline is unilaterally linked to a diisocyanate compound to obtain a monoisocyanate structure compound. If the process is not properly selected, side reactions will occur, i.e., both sides of the diisocyanate compound will be linked. In this case, the isocyanate groups on both sides of the diisocyanate compound will be completely consumed. The side reaction product, lacking active groups, cannot react with the hydroxyl or carboxyl groups in the free SBS fragment, thus losing the possibility of network structure repair. To effectively suppress the occurrence of side reactions and ensure a stable and controllable reaction, it has been determined that reaction temperature and reaction rate are the key factors for regulating the reaction process, determining the structural purity of the target product, and the final yield. In this invention, a reaction temperature of 5℃ and a dropping rate of 0.5 ml / min are used to efficiently and stably prepare the regenerant with the monoisocyanate structure described in this invention.
[0026] (3) When the regenerator proposed in this invention is used to prepare recycled asphalt, the overall performance of the recycled asphalt is better when the amount of light oil component B is 4% of the mass of asphalt and the amount of regenerator component A is 1% of the mass of asphalt. Some properties even exceed those of the original asphalt. Through experiments on the changes in the performance of aged SBS modified asphalt by the regenerator proposed in this application under different dosages, it was found that the regenerator proposed in this application can have a good regeneration effect on the high temperature rutting resistance, medium temperature fatigue resistance and low temperature cracking resistance of aged SBS modified asphalt at medium and low dosages. Overall, the performance is best when the dosage is 1%. Attached Figure Description
[0027] Figure 1 The chemical reaction formulas for 4,4-diisocyanate dicyclohexylmethane and 4-methoxyaniline provided in the embodiments of the present invention; Figure 2 Infrared spectra provided in the embodiments of the present invention; Figure 3 The embodiments provided by this invention include curves showing the variation of the logarithmic and complex modulus of asphalt with temperature for each group. Figure 4 The phase angle of each group of asphalt as a function of temperature is shown in the embodiments provided by the present invention. Figure 5 A bar chart comparing the elastic recovery rates of asphalt at different temperatures in the embodiments provided by the present invention; Figure 6 A comparative bar chart of the irreversible compliance of asphalt at different temperatures in the embodiments provided by the present invention; Figure 7 The fatigue life variation curves of each group of asphalt in the embodiments provided by the present invention; Figure 8 A bar chart comparing the low-temperature recycling effects of different groups of asphalt in the embodiments provided by the present invention; Figure 9 Fluorescence micrographs of each group of asphalt in the embodiments provided by the present invention; Figure 10 A bar chart comparing the fluorescence area of each group of asphalt in the embodiments provided by the present invention; Figure 11 A quantitative comparison diagram of the functional group area of recycled asphalt in each group of asphalt in the embodiments provided by the present invention.
[0028] In the figure: HC is the regenerator component A, HMDI is 4,4-diisocyanate dicyclohexylmethane, PA is 4-methoxyaniline; SMB is the new asphalt group, ASMB is the old asphalt group, KL-AR is the experimental group, AR is the control group 1, HMDI-AR is the control group 2, and HP-AR is the control group 3. Detailed Implementation
[0029] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, examples, and comparative examples. The following examples and comparative examples are only used to more clearly illustrate the technical solutions of the present invention, so that those skilled in the art can better understand and utilize the present invention, and are not intended to limit the scope of protection of the present invention.
[0030] The experimental methods, production processes, instruments, and equipment involved in the embodiments and comparative examples of this invention are all conventional names in the art, and are very clear and distinct in the relevant application fields. Those skilled in the art can understand the conventional process steps and apply the corresponding equipment based on the names, and implement them according to conventional conditions or conditions recommended by the manufacturer.
[0031] The raw materials or reagents used in the embodiments and comparative examples of this invention are not subject to any special restrictions on their source and are all conventional products that can be purchased commercially.
[0032] Example 1 Preparation of regenerant
[0033] I. Preparation of Regenerant
[0034] This embodiment provides an aged SBS modified asphalt rejuvenator, comprising component A and component B. Component A, by mass parts, includes: 2.2-2.64 parts of diisocyanate compound, 1-1.2 parts of primary amine compound, 1.5-1.8 parts of solvent, and 0.1 parts of stabilizer; a monoisocyanate compound is generated through the reaction of the diisocyanate compound and the primary amine compound. Component B includes light oil. In this embodiment, the light oil is aromatic oil, the diisocyanate compound is 4,4-diisocyanate dicyclohexylmethane (HMDI), the primary amine compound is 4-methoxyaniline (PA), the solvent is dichloromethane, and the stabilizer is acetone. The mass ratio of HMDI to PA is 2.2:1. Those skilled in the art will readily understand that replacing 4,4-diisocyanate dicyclohexylmethane, 4-methoxyaniline, dichloromethane, and acetone in the examples with similar functional substances such as diisocyanate compounds, primary amine compounds, solvents, and stabilizers will achieve essentially the same effect. The inventors have verified this in experiments, and will not elaborate further here. Only HMDI and PA are used as representatives of diisocyanate compounds and primary amine compounds in the experiments.
[0035] The specific quality of the materials used to prepare component A of the aged SBS modified asphalt recycling agent is shown in Table 1.
[0036]
[0037] Prepare aged SBS modified asphalt recycling agent according to the following steps: 1) Add 150g of dichloromethane to a dry three-necked flask, then add 100g of PA, start the stirrer and maintain a speed of 200 rpm, control the water bath temperature at 5℃, and stop stirring after PA is completely dissolved to obtain a mixed solution of primary amine and solvent.
[0038] 2) Add 10g of acetone evenly to the above mixed solution, and maintain the mixing temperature at 5℃ to obtain a dark brown liquid.
[0039] 3) Add 220g HMDI to a burette and add it slowly and evenly to the above dark brown liquid at a dropping rate of 0.5ml / min while stirring continuously at a speed of 200rpm. Continue stirring until the diisocyanate compounds are completely added. During the reaction, take out a portion of the sample to determine the isocyanate content to ensure that the reaction proceeds normally. After the reaction is completed, let it stand for 1 hour. Perform low-temperature distillation at 39℃ to remove dichloromethane from the product and obtain a white emulsion-like regenerant component A for later use.
[0040] 4) Store component A of the regenerator in a sealed brown reagent bottle, and store it separately from component B (aromatic oil) of the regenerator at room temperature, away from moisture and light. When needed, prepare the solution according to the specified ratio for the regeneration of aged SBS modified bitumen-based materials.
[0041] II. Verification: Determination of Isocyanate Content
[0042] In this embodiment, HMDI and PA react to generate a monoisocyanate compound, as shown in the chemical reaction formula below. Figure 1 As shown. To verify the reaction effect of HMDI and PA, infrared spectroscopy analysis was performed on regenerant component A (HC), HMDI, and PA, respectively. Figure 2 As shown, HMDI and HC at 2250cm -1 The appearance of a high-intensity peak indicates the presence of isocyanate groups, suggesting that isocyanate groups are still retained in the product after the synthesis reaction. PA values range from 3300 to 3500 cm⁻¹. -1 The presence of a distinctive double peak at this point is a hallmark of significant stretching vibrations in primary amines. When HMDI and PA react, the peak value is between 3300 and 3500 cm⁻¹. -1 The disappearance of the peak at 3361 cm⁻¹ indicates that the amino group in PA has been completely consumed. It is noteworthy that the peak at 3361 cm⁻¹ in HC... -1 The relatively broad weak peak at 1627 cm⁻¹ represents the stretching vibration of the nitrogen-hydrogen bond in the urea bond. -1 The moderately intense peaks at 1558 cm⁻¹ represent the stretching vibrations of the carbon-oxygen double bonds in the urea bond. -1 The moderately intense peaks at 1226 cm⁻¹ represent in-plane bending vibrations of the nitrogen-hydrogen bonds in the urea bond. The presence of these peaks indicates the existence of the urea bond. Additionally, at 1226 cm⁻¹... -1The new peak at the point represents the asymmetric stretching vibration of the methoxy group in PA. Therefore, the reaction process involves both the formation of urea bonds and the retention of some isocyanate functional groups, indicating that PA was successfully added to one side of HMDI, and the monoisocyanate compound was successfully prepared.
[0043] Example 2: Preparation of Recycled Asphalt
[0044] In this embodiment, the original asphalt was made of finished SBS modified asphalt, and its basic properties are shown in Table 2.
[0045]
[0046] In this embodiment, the SBS modified asphalt was aged in a thin-film oven at 163°C for 5 hours. The short-term aged asphalt was then placed in a pressurized aging container and aged at 2.1 MPa and 100°C for 25 hours to simulate the long-term aging of asphalt.
[0047] Take 1 kg of aged SBS modified asphalt and prepare recycled SBS modified asphalt with different amounts of recycling agent. The aromatic oil content is 4% of the asphalt mass. Without changing the aromatic oil content, change the content of recycling agent component A to 0.5%, 1% and 1.5% of the asphalt mass. The prepared materials are shown in Table 3.
[0048]
[0049] Regenerate it by following these steps: Aged SBS modified asphalt was heated to a fluid state at a stirring temperature of 150°C, and 4% aromatic oil was added. The mixture was stirred continuously at 800 rpm for 10 minutes. Recycling agent component A was then added to the homogeneous mixture at dosages of 0.5%, 1%, and 1.5%, respectively, and the mixture was stirred continuously at 800 rpm for 15 minutes to obtain recycled SBS modified asphalt.
[0050] Example 3: Changes in the performance of regenerant at different dosages
[0051] This embodiment verifies the effect of the rejuvenator proposed in this application on the performance of aged SBS modified asphalt under different dosages. The asphalt from Example 2 was used as the test object in this embodiment. Temperature scanning, linear amplitude scanning, and bending beam rheological tests were conducted on virgin asphalt, aged asphalt, and rejuvenated asphalt with different rejuvenator dosages. The results were compared by examining the complex shear modulus and phase angle measured by temperature scanning, the fatigue life measured by linear amplitude scanning, and the creep modulus and creep rate measured by bending beam rheological tests. The test results are shown in Table 4. It can be seen that the performance of the asphalt rejuvenated by the rejuvenator provided in this application can reach the level of virgin asphalt and meet road application requirements.
[0052]
[0053] As shown in Table 4, with the increase of the recycling agent content proposed in this application, the complex shear modulus of the recycled asphalt gradually increases, while the phase angle gradually decreases. Its complex shear modulus is significantly higher than that of the undiluted asphalt, indicating that the addition of the recycling agent effectively increases the hardness of the asphalt. The phase angle, however, is lower than that of the undiluted asphalt, indicating that the recycling agent reduces the viscosity of the asphalt and improves its elasticity. The degree of recovery of both the complex shear modulus and the phase angle meets the technical requirements for SBS modified asphalt, demonstrating a significant recycling effect.
[0054] The fatigue life gradually decreased with increasing recycling agent dosage, and only at a dosage of 0.5% did it effectively restore the fatigue resistance of asphalt, even surpassing that of undisturbed asphalt. The fatigue life at a dosage of 1% also met the requirements for use with SBS modified asphalt, indicating that the recycling agent proposed in this application can effectively restore the fatigue resistance of aged SBS modified asphalt at medium to low dosages.
[0055] The creep rate initially increased and then decreased with increasing rejuvenator dosage, and the values at 0.5% and 1% dosages were higher than those of the virgin asphalt, indicating that the rejuvenator effectively restored the resistance of aged SBS modified asphalt to creep failure at low temperatures. The change in stiffness modulus was similar to that of creep rate; at 0.5% and 1% dosages, the rejuvenating effect on aged SBS modified asphalt was superior to that on virgin asphalt. This demonstrates that the rejuvenator proposed in this application can effectively restore the low-temperature cracking resistance of asphalt at medium to low dosages.
[0056] In summary, the test results show that the rejuvenator proposed in this study, while retaining the excellent high-temperature resistance of HMDI, can further improve the fatigue resistance and low-temperature cracking resistance of asphalt, thus compensating for the low recovery efficiency of HMDI in medium and low temperature performance. Through experiments on the changes in the properties of aged SBS modified asphalt by the rejuvenator proposed in this application at different dosages, it was found that the rejuvenator proposed in this application can achieve good rejuvenation effects on the high-temperature rutting resistance, medium-temperature fatigue resistance, and low-temperature cracking resistance of aged SBS modified asphalt at medium and low dosages, even exceeding the level of the original asphalt, indicating that the rejuvenator has a good rejuvenation effect.
[0057] Example 4: Performance Verification of Regenerant
[0058] This embodiment verifies the effect and significance of the recycling agent provided in this application on the recycling of aged SBS modified asphalt. The asphalt from Example 2 was used as the test object. Original asphalt was designated as the new asphalt group, aged asphalt as the old asphalt group, and recycled SBS modified asphalt with 1% of recycling agent component A was designated as the experimental group. Aging asphalt was treated with aromatic oil to obtain control group 1; aging asphalt was treated with aromatic oil and 1% HMDI to obtain control group 2; and aging asphalt was treated with a mixture of aromatic oil and 1% HMDI+PA to obtain control group 3. The performance differences of the four recycled asphalt samples were compared using macroscopic and microscopic testing methods to explore the influence of the recycling agent on the recycling effect. In the control groups, the aromatic oil content was 4% of the added asphalt mass, and 1% referred to 1% of the added asphalt mass. Asphalt function tests were conducted on the recycled SBS modified asphalt obtained through the above different treatment methods, and all tests were conducted in accordance with the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering". The test groups are shown in Table 5 below.
[0059]
[0060] Preparation of recycled asphalt in control group 1: After heating the aged SBS modified asphalt to a fluid state, 4% aromatic oil by weight of the asphalt was added to the aged SBS modified asphalt, and the mixture was continuously stirred at 800 rpm for 10 minutes to obtain control group 1.
[0061] Preparation of recycled asphalt in control group 2: After heating aged SBS modified asphalt to a fluid state, 4% aromatic oil (by weight of the asphalt) was added to the aged SBS modified asphalt, and the mixture was continuously stirred at 800 rpm for 10 minutes. Subsequently, HMDI was added at a dosage of 1% to the aged asphalt containing 4% aromatic oil, and the mixture was continuously stirred at 800 rpm for 15 minutes to obtain control group 2.
[0062] Preparation of recycled asphalt in control group 3: After heating aged SBS modified asphalt to a fluid state, 4% aromatic oil (by weight of the asphalt) was added to the aged SBS modified asphalt, and the mixture was continuously stirred at 800 rpm for 10 minutes. Then, 0.31% PA was added to the aged asphalt containing 4% aromatic oil, followed by 0.69% HMDI, and the mixture was continuously stirred at 800 rpm for 15 minutes to obtain control group 3.
[0063] I. Macroscopic performance effect
[0064] 1. High-temperature deformation resistance
[0065] (1) Dynamic shear modulus and phase angle
[0066] The hardness and recycling effect of each group of recycled asphalt were evaluated by dynamic shear modulus. For example... Figure 3 As shown in the figure, the temperature scan results reveal that the logarithmic and complex moduli of KL-AR and HMDI-AR are very close, indicating that KL-AR retains the restorative effect of HMDI-AR on the high-temperature properties of asphalt. The logarithmic and complex moduli of HP-AR and AR are basically the same, and lower than that of KL-AR, indicating that simply adding the two unsynthesized materials cannot effectively restore the logarithmic and complex modulus of ASMB.
[0067] The viscoelastic regeneration effect of each group of recycled asphalt was evaluated by phase angle. For example... Figure 4 As shown in the figure. Based on the phase angle data, the phase angle changes of KL-AR and HMDI-AR are very similar, both initially decreasing and then increasing. This further illustrates that KL-AR can retain the inhibitory effect of HMDI-AR on the viscoelasticity of ASMB at high temperatures. HP-AR and AR have very similar phase angles, both exhibiting an enhancement of ASMB viscosity and a weakening of ASMB elasticity.
[0068] (2) Recovery rate and irreversible creep compliance
[0069] The regeneration effect of each group of recycled asphalt was characterized by the R value obtained from the multiple stress creep (MSCR) test. Figure 5 As shown in the figure, the elastic recovery rate (R value) of MSCR shows that the R values of HMDI-AR and KL-AR are close to those of SMB, indicating that KL-AR effectively retains the elastic recovery ability of HMDI-AR for ASMB at high temperatures. The R value of AR is even lower than that of ASMB, indicating that the addition of aromatic oil alone weakens the elastic recovery ability of ASMB. The R value of HP-AR is between that of KL-AR and AR, indicating that HP-AR inhibits the weakening of the elastic recovery ability of AR for ASMB, but it is still far inferior to the elastic recovery ability of KL-AR for ASMB.
[0070] The irreversible compliance (Jnr) of each group of recycled asphalt was characterized by its rutting resistance and recycling effectiveness through the MSCR test. For example... Figure 6 As shown, the Jnr of KL-AR is also between that of HMDI-AR and HP-AR, and close to that of HMDI-AR, indicating that KL-AR retains the recovery effect of HMDI-AR on the rutting resistance of ASMB at high temperatures. The Jnr of HP-AR is similar to that of AR, but significantly higher than that of HMDI-AR and KL-AR, indicating that HP-AR failed to further recover the Jnr of ASMB based on AR, showing poor rutting resistance recovery effect.
[0071] 2. Mid-temperature fatigue resistance
[0072] (1) Fatigue life
[0073] The fatigue life obtained through linear amplitude scanning tests characterizes the fatigue performance and regeneration effect of each group of recycled asphalt, such as... Figure 7 As shown in the figure, the fatigue life of KL-AR is higher than that of HMDI-AR at all stress levels, indicating that KL-AR can effectively improve the mid-temperature fatigue resistance of ASMB. The fatigue life of AR remains at a relatively high level among the four regenerators under all stresses, indicating that AR has a better effect on restoring the fatigue resistance of ASMB. HP-AR has the lowest fatigue life, even approaching the level of ASMB, indicating that HP-AR cannot effectively restore the fatigue resistance of ASMB.
[0074] 3. Low-temperature crack resistance
[0075] The stiffness modulus (S) and creep rate (m) obtained by bending beam rheological tests characterize the low-temperature recycling effect of each group of recycled asphalt, such as... Figure 8 As shown, the stiffness modulus of KL-AR is lower than that of AR, HMDI-AR, and HP-AR at all temperatures, and close to that of SMB, indicating that KL-AR has the best recovery effect on the low-temperature crack resistance of ASMB. In terms of creep rate, the values of KL-AR at all temperatures are higher than those of AR, HMDI-AR, and HP-AR, indicating that KL-AR has the best recovery effect on the low-temperature creep resistance of ASMB. This shows that the regenerator provided in this application improves the ability of HMDI to recover the low-temperature crack resistance of ASMB.
[0076] II. Microscopic Performance Effects
[0077] This embodiment investigates the effects of AR, HMDI-AR, KL-AR, and HP-AR on the microstructure properties of aged SBS modified asphalt using fluorescence microscopy and Fourier transform infrared spectroscopy (FTIR).
[0078] 1. Surface micromorphology
[0079] The surface microstructure of different recycled asphalt samples was investigated using fluorescence microscopy. Figure 9 Fluorescence images and Figure 10The quantitative results of the corresponding polymer area ratio in asphalt were analyzed. Compared with AR, the fluorescence area ratios of HMDI-AR, KL-AR, and HP-AR in the fluorescence images increased by 1021%, 1073%, and 438%, respectively. The significant increase in the number of fluorescent particles and the larger area of individual fluorescent particles indicate that the experimental group, HMDI-AR, and HP-AR all have the function of repairing the polymer network. HP-AR also has a rebuilding effect on the polymer network in aged asphalt, which is attributed to the repairing effect of HMDI in HP-AR, but the rebuilding efficiency is significantly lower than that of HMDI-AR and KL-AR. Therefore, KL-AR has the best repair effect on the polymer network of aged asphalt, indicating that the regenerator provided in this application improves the repair efficiency of HMDI on degraded SBS.
[0080] 2. Chemical functional groups
[0081] The functional group evolution of recycled asphalt was quantitatively evaluated using the Base Bituminous Aging Index (BBSI) and the SBS Structural Integrity Index (SSDI). For example... Figure 11 As shown, the SSDI of HMDI-AR, KL-AR, and HP-AR increased by 45%, 38%, and 24% respectively compared to AR, indicating that all three compounds can significantly repair the SBS polymer network structure. Among them, HMDI-AR showed the best repair effect on SBS, followed by KL-AR, with HP-AR showing the worst. HP-AR's BBSI was significantly lower than AR, indicating a significant regeneration effect on the base asphalt phase. HMDI-AR's BBSI was significantly higher than AR, indicating that HMDI does not have the ability to regenerate base asphalt. Therefore, the significant decrease in HP-AR's BBSI is due to the regeneration effect of PA on the base asphalt. In contrast, the change in KL-AR's BBSI relative to AR was not significant, indicating that KL-AR primarily targets the degradation of SBS, rather than the base asphalt.
[0082] The experimental group (KL-AR), control group 1 (AR), control group 2 (HMDI-AR), and control group 3 (HP-AR) of recycled asphalt used in this application, respectively, demonstrated the regeneration advantages of the regenerator provided in this application on the performance of recycled asphalt through macroscopic and microscopic tests. The SBS modified asphalt regenerated by the regenerator provided in this application significantly improved its medium and low temperature performance while ensuring the superior high-temperature performance of HMDI. It significantly mitigated the mutually exclusive effects of HMDI and PA on the performance of recycled asphalt, compensated for the low recovery efficiency of HMDI in medium and low temperature performance, and even exceeded the level of the original asphalt in terms of regeneration effect, indicating that the regenerator has a significant regeneration effect.
[0083] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.
Claims
1. An aged SBS modified asphalt recycling agent, characterized in that, It includes component A and component B; by mass parts, component A includes: 2.2-2.64 parts of diisocyanate compound, 1-1.2 parts of primary amine compound, and 0.1 parts of stabilizer, wherein the diisocyanate compound and primary amine compound can react to generate monoisocyanate compound; component B includes light oil, and components A and B are used in combination.
2. The aged SBS modified asphalt rejuvenator according to claim 1, characterized in that, Component A further includes 1.5-1.8 parts of solvent; the mass ratio of the diisocyanate compound to the primary amine compound is 2.2:
1.
3. The aged SBS modified asphalt rejuvenator according to claim 2, characterized in that, The solvent is at least one of dichloromethane, toluene, and tetrahydrofuran.
4. The aged SBS modified asphalt rejuvenator according to claim 1, characterized in that, The diisocyanate compound is at least one selected from 4,4-diisocyanate dicyclohexylmethane, toluene diisocyanate, and 4,4'-diphenylmethane diisocyanate.
5. The aged SBS modified asphalt rejuvenator according to claim 1, characterized in that, The primary amine compound is a compound of methoxyaniline.
6. The aged SBS modified asphalt rejuvenator according to claim 1, characterized in that, The stabilizer is at least one of acetone and acetylacetone.
7. The aged SBS modified asphalt recycling agent according to claim 1, characterized in that, The light oil is classified into at least one of aromatic oil, soybean oil, and catalytic cracking oil.
8. A method for preparing an asphalt recycling agent as described in claim 2, characterized in that, Includes the following steps: S1. Maintain the system temperature at 5℃, then add the primary amine compound to the solvent and mix evenly to obtain a primary amine-solvent mixed solution; S2. Add the stabilizer to the mixed solution of S1, and maintain the mixing temperature at 5°C to obtain a dark brown liquid. S3. Add the diisocyanate compound to the dark brown liquid obtained in S2 at a dropping rate of 0.5 ml / min. Continue stirring until the diisocyanate compound is completely added. After the reaction is complete, let it stand for 1 hour. Then, perform vacuum distillation at 39°C to remove the residual solvent in the system and obtain a white emulsion-like regenerator component A for later use. S4. Place component A in a brown reagent bottle and seal it for storage. Store it separately from component B at room temperature, away from moisture and light. When needed, prepare it according to the ratio for the regeneration of aged SBS modified bitumen materials.
9. The application of an asphalt recycling agent as described in any one of claims 1-7 in the recycling of waste asphalt, characterized in that, When preparing recycled asphalt, the aged SBS modified asphalt is heated to a fluid state, and then 4% of the asphalt mass of recycling agent component B is added at a stirring temperature of 150°C, and stirred continuously at 800 rpm for 10 minutes; then 0.5%~1.5% of the asphalt mass of recycling agent component A is added, and stirred continuously at 800 rpm for 15 minutes before use.
10. The application of the asphalt recycling agent according to claim 9 in the recycling of waste asphalt, characterized in that, The amount of the recycling agent component A is 1% of the asphalt mass.