Aged SBS (Styrene Butadiene Styrene) modified asphalt repair type regenerant and preparation method thereof

Abstract

The invention discloses an aged SBS modified asphalt repair type regenerant and a preparation method thereof, and the regenerant is prepared by mixing aromatic hydrocarbon oil with 1, 4-butanediol diglycidyl ether and then mixing with rubber powder. Wherein the dosage of each component is as follows: 3-8 parts of aromatic hydrocarbon oil, 0.5-2 parts of 1, 4-butanediol diglycidyl ether and 8-10 parts of rubber powder. The repairing type regenerant can uniformly improve the high-temperature performance, ductility, recovery rate and other performance of SBS asphalt, and the problem of imbalance caused by prominent or backward individual indexes due to single components is avoided. And finally, the comprehensive performance of the regenerated asphalt is superior to that of the aged asphalt and is better than that of the common mixed regenerated asphalt, so that the comprehensive quality improvement of the performance of the aged SBS modified asphalt is realized.

Description

Technical Field

[0001] This invention relates to the field of road materials, and in particular to an aged SBS modified asphalt repair regenerator and its preparation method. Background Technology

[0002] SBS modified asphalt, with its superior properties, has become a core material for pavement engineering in heavy-duty traffic roads and special climate zones. As existing roads age, a large number of SBS modified asphalt pavements require renovation due to aging and load-bearing wear. However, because the cost of SBS modified asphalt is 30% to 50% higher than that of ordinary base asphalt, directly constructing new road sections during renovation would pose a significant challenge to the overall pavement budget. Furthermore, the asphalt components in many old pavements are difficult to degrade naturally, leading to environmental pollution problems. Therefore, research on the recycling of aged SBS modified asphalt to achieve performance restoration and resource recycling has become a research hotspot in the field of road engineering.

[0003] In existing regenerator research and development, aromatic oils are a relatively common base asphalt regenerator. 1,4-Butanediol diglycidyl ether (BUDGE) has the ability to repair degraded SBS and has also appeared in related studies on the regeneration of aged SBS-modified asphalt. Aromatic oils have excellent compatibility with asphalt components, effectively softening the hardened asphaltenes in aged SBS-modified asphalt, replenishing lost light active components, and significantly improving the low-temperature ductility and plastic deformation capacity of asphalt. BUDGE can repair the SBS molecular network that is broken due to aging through molecular chain cross-linking, enhancing the elastic recovery performance and high-temperature shear strength of asphalt. However, both of these components have obvious shortcomings when used alone as regenerators: aromatic oils tend to lower the softening point of asphalt, have insufficient high-temperature stability, and are prone to secondary aging caused by the volatilization of light components with long-term use. BUDGE, on the other hand, has poor interfacial wettability with aged asphalt, making it difficult to disperse evenly, which can easily cause excessive local elasticity and insufficient plasticity in asphalt, and the low-temperature crack resistance cannot be guaranteed.

[0004] If the two are directly mixed, the hydrophobicity of BUDGE will cause it to gradually aggregate in the mixture, resulting in poor stability of the treated modified asphalt and even precipitation. Not only will they fail to complement each other, but they will also exacerbate the separation of components in the recycled asphalt, leading to a comprehensive decline in its various performance indicators. Therefore, how to solve the synergistic effect problem of aromatic oil and BUDGE through component design and process optimization, and develop a repair-type 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 overcoming existing technological bottlenecks. Summary of the Invention

[0005] One of the objectives of this invention is to provide a regenerator for repairing aged SBS modified asphalt, which can comprehensively improve multiple properties of SBS modified asphalt and avoid the imbalance caused by individual indicators being prominent or lagging behind due to single components.

[0006] The second objective of this invention is to provide a method for preparing a regenerator for repairing aged SBS modified asphalt, which can yield a regenerator with balanced performance in various aspects. Ultimately, the overall performance of the regenerated asphalt is not only superior to that of aged asphalt, but also surpasses that of ordinary mixed regenerated asphalt, thus achieving a comprehensive improvement in the performance of aged SBS modified asphalt.

[0007] The third objective of this invention is to provide the application of aged SBS modified asphalt repair regenerator in the recycling and reuse of bridge deck and pavement materials.

[0008] The first aspect of this invention discloses a regenerating agent for repairing aged SBS modified asphalt, which is added to recycled SBS modified asphalt. It is prepared by first mixing aromatic oil with 1,4-butanediol diglycidyl ether, and then mixing with rubber powder. The weight parts of each component are: 3-8 parts aromatic oil, 0.5-2 parts 1,4-butanediol diglycidyl ether, and 8-10 parts rubber powder.

[0009] Preferably, the amount of aromatic oil is 4 parts, the amount of 1,4-butanediol diglycidyl ether is 1 part, and the amount of adhesive powder is 10 parts.

[0010] The aged SBS modified asphalt repair regenerator also includes 0.1-0.3 parts sulfur powder and 0.1-0.45 parts polyvinyl alcohol.

[0011] Preferably, the amount of sulfur powder is 0.1 parts and the amount of polyvinyl alcohol is 0.15 parts.

[0012] The second aspect of this invention discloses a method for preparing the aged SBS modified asphalt repair rejuvenator, comprising the following steps: S1. After recovering SBS modified bitumen, take 3-8 parts of aromatic oil and 0.5-2 parts of 1,4-butanediol diglycidyl ether and mix them at room temperature for 3 minutes. S2. Take 8-10 parts of the adhesive powder, put it into 100℃ water and heat for 10 minutes, then remove and air dry to keep it dry; S3. In order to reduce the hardness of the rubber powder and improve its activity, the air-dried rubber powder was preheated at 60°C for 5 minutes, and then the rubber powder was stirred at 1000 rpm. Then, the mixture of aromatic oil and 1,4-butanediol diglycidyl ether in S1 was added while stirring continuously, and stirring was continued for 5 minutes. S4. Simultaneously add 0.1-0.2 parts sulfur powder and 0.15-0.3 parts polyvinyl alcohol, and stir at 1500 rpm for 5 minutes to obtain aged SBS modified asphalt repair regenerator.

[0013] The third aspect of this invention discloses the application of the aged SBS modified asphalt repair regenerator in the recycling and reuse of bridge deck and pavement materials.

[0014] First, the repair-type regenerator obtained by this invention effectively improves five properties: irreversible creep compliance, recovery rate, ductility, creep rate-to-stiffness modulus ratio, and softening point difference. Unlike the pure superposition of three main materials, the special treatment method makes the values ​​of each parameter close to those of new SBS modified asphalt. Second, irreversible creep compliance, recovery rate, and ductility are interrelated. The formulation and treatment method of this invention ensure that all three are increased uniformly and in a balanced manner, avoiding a situation where one parameter is outstanding while others are not, or even seriously dragging down the performance. Finally, the new repair-type regenerator improves the storage stability of modified asphalt. A major drawback of traditional regenerated asphalt is its poor storage stability. After treatment with the repair-type regenerator of this invention, the old SBS modified asphalt not only shows a significant recovery in performance but also a substantial improvement in stability.

[0015] The remedial regenerator of this invention uses readily available raw materials, has a simple preparation process, and is highly compatible with existing asphalt recycling equipment, requiring no additional investment in large-scale equipment. SBS modified asphalt recycled using the method of this invention can be directly applied to plant-mixed hot recycling and in-situ hot recycling projects for old asphalt pavements, significantly improving the recycling rate of old asphalt mixtures, reducing the consumption of new asphalt raw materials, and minimizing waste pollution from waste asphalt mixtures. Simultaneously, the recycled asphalt exhibits excellent road performance, extending pavement service life and significantly reducing pavement maintenance costs, resulting in significant economic, social, and environmental benefits. Attached Figure Description

[0016] Figure 1 These are fluorescence micrographs of the polymer network distribution of SBS-modified bitumen after different treatments.

[0017] Figure 2 This is a graph showing the proportion of fluorescence area quantification. Detailed Implementation

[0018] 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.

[0019] 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.

[0020] 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. Example 1: Preparation of a regenerator for repairing aged SBS modified asphalt.

[0021] Prepare the test materials as shown in Table 1;

[0022] Next, prepare the aged SBS modified asphalt repair regeneration agent according to the following steps: 1) Add 400g of aromatic oil to a beaker, stir manually at room temperature and add 100g of BUDGE, and continue stirring for 3 minutes.

[0023] 2) Take 1 kg of adhesive powder, put it into 100℃ water and heat for 10 minutes, then take it out and air dry it to keep it dry.

[0024] 3) Place the air-dried rubber powder in a 60℃ oven for 5 minutes to soften it and keep it active. Then add the rubber powder to a magnetic stirring pot and stir at 1000 rpm. Then add the prepared aromatic oil and BUDGE mixture while stirring continuously and continue stirring for 5 minutes.

[0025] 4) Add 10g of sulfur powder and 15g of polyvinyl alcohol to the well-stirred mixture, and stir at 1500rpm for 5min to obtain aged SBS modified asphalt repair regenerator. Example 2: Regeneration of aged SBS modified bitumen.

[0026] Take 10 kg of aged SBS modified asphalt from the road to be renovated and recycle it according to the following steps: 1) Heat the aged SBS modified asphalt to 160℃ until it reaches a fluid state, add 50g of N,N-dimethylbenzylamine, and shear at 1000rpm for 5min.

[0027] 2) Add 800g of the repair-type regenerant prepared in Example 1, increase the shearing speed to 3000rpm, and shear for 20min.

[0028] 3) Place the sheared mixture in an environment of 180℃ for 30 minutes to swell and develop, and obtain the regenerated SBS modified asphalt. Example 3: Preparation of a regenerator for repairing aged SBS modified asphalt.

[0029] Prepare the test materials as shown in Table 2;

[0030] Next, prepare the aged SBS modified asphalt repair regeneration agent according to the following steps: 1) Add 600g of aromatic oil to a beaker, stir manually at room temperature and add 200g of BUDGE, and continue stirring for 3 minutes.

[0031] 2) Take 900g of adhesive powder, put it into 100℃ water and heat for 10 minutes, then take it out and air dry it to keep it dry.

[0032] 3) Place the air-dried rubber powder in a 60℃ oven for 5 minutes to soften it and keep it active. Then add the rubber powder to a magnetic stirring pot and stir at 1000 rpm. Then add the prepared aromatic oil and BUDGE mixture while stirring continuously and continue stirring for 5 minutes.

[0033] 4) Add 20g of sulfur powder and 30g of polyvinyl alcohol to the well-stirred mixture, and stir at 1500rpm for 5min to obtain aged SBS modified asphalt repair regenerator. Example 4: Verification of the effect of the regenerant.

[0034] The recycled SBS modified asphalt obtained in Example 2 was compared with SBS modified asphalt obtained through different treatment methods to conduct asphalt function tests. All tests were conducted in accordance with the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering". The specific contents are as follows: The irreversible creep compliance test, referring to JTG 3410-2025 T0647, simulates the creep-recovery behavior of asphalt under light and heavy load conditions using a dynamic shear rheometer (DSR) to conduct multi-stress creep and recovery tests on asphalt. Irreversible creep compliance is a high-temperature performance evaluation index; within a certain range, a smaller value reflects better rutting resistance of asphalt at high temperatures.

[0035] The recovery rate test was conducted according to JTG 3410-2025 T0647. The recovery rate reflects the elastic properties of asphalt, which is related to the spatial dispersion structure of the polymer in the asphalt. Within a certain range, we generally believe that the higher the recovery rate, the better the elasticity of the asphalt, and the stronger its ability to recover its original shape after being deformed under pressure.

[0036] The ductility test, conducted according to JTG 3410-2011 T0605, measures the length of the asphalt specimen at fracture under specified temperature and tensile speed, reflecting the plastic deformation capacity of asphalt. Ductility reflects the ductility of asphalt at low temperatures; within a certain range, a higher value indicates stronger ductility.

[0037] The creep rate and stiffness modulus ratio test was conducted according to JTG 3410-2025 T0627. The creep rate and stiffness modulus ratio reflects the crack resistance of asphalt at low temperatures; within a certain range, the higher the value, the stronger the crack resistance.

[0038] The softening point difference test was conducted according to JTG 3410-2011 T0606. The softening point difference reflects the storage stability of asphalt; within a certain range, a larger value indicates a more severe segregation of the asphalt.

[0039] The experimental groups are shown below, with both the experimental and control groups treated with the old SBS modified asphalt according to the method in Example 2.

[0040] Experimental group: Regenerated SBS modified bitumen obtained according to Example 2.

[0041] New Asphalt Group: New SBS Modified Asphalt.

[0042] Old Asphalt Group: Recycled old SBS modified asphalt.

[0043] Control group 1: Products obtained by treating old SBS modified bitumen with only aromatic oil.

[0044] Control group 2: Products obtained by treating old SBS modified bitumen with only rubber powder.

[0045] Control group 3: Products obtained by treating old SBS modified bitumen with only BUDGE.

[0046] Control group 4: The product obtained by treating old SBS modified bitumen with aromatic oil + BUDGE.

[0047] Control group 5: The product obtained by treating old SBS modified bitumen with aromatic oil and rubber powder.

[0048] Control group 6: The product obtained by treating old SBS modified bitumen with rubber powder and BUDGE.

[0049] Control group 7: First, mix the rubber powder and aromatic oil, stir evenly, then add BUDGE, and add sulfur powder and polyvinyl alcohol as per Example 1. After mixing evenly, use it to treat old SBS modified asphalt to obtain the product.

[0050] The experimental results are shown in Table 3. It can be seen that aromatic oil, rubber powder, and BUDGE have different effects on the five properties. Compared with the old asphalt group, some parameters were improved after treatment with aromatic oil, rubber powder, and BUDGE individually, while others deteriorated. For example, control group 1 showed worse performance in irreversible creep compliance and recovery rate; control group 2 showed worse performance in ductility and softening point difference; and control group 3 showed worse performance in irreversible creep compliance, recovery rate, and softening point difference. Therefore, it is impossible to determine the performance of the aromatic oil, rubber powder, and BUDGE combination; further comparison of the performance parameters after pairwise combinations is needed.

[0051] Based on mathematical logic, when aromatic oil, rubber powder, and BUDGE are combined in pairs, the combination of two positive results on the same parameter will yield a positive result, which may be better than the result of treating them individually; the combination of two negative results on the same parameter will yield a negative result, which may be worse than the result of treating them individually; the conclusion of the combination of one positive and one negative result on the same parameter is uncertain.

[0052] However, some conclusions suggest that the above mathematical logic does not hold true. For example, regarding the difference in softening point, the results of treatment with rubber powder and BUDGE alone were worse than those of the old asphalt group, but after three sets of repeated tests, the results of treatment with both in combination were better. In other combinations, the degree of superposition varied, some approaching the sum of numbers, while others were multiples, making it impossible to infer from common sense.

[0053] For the experimental group, all five performance indicators were superior to those of the old asphalt group, and all parameters were optimized. The only areas where the experimental group was inferior were ductility (below control group 4) and recovery rate (below control group 6). Ductility, recovery rate, and non-recoverable creep compliance are dynamically correlated; as ductility increases, non-recoverable creep compliance also increases, leading to decreased rutting resistance at high temperatures and a lower recovery rate. Control group 4 had higher ductility than the experimental group, but its associated non-recoverable creep compliance was significantly higher than the other groups, indicating an imbalance in this aspect. The prominence of one indicator negatively impacted other performances, rendering it impractical. Similarly, in control group 6, although the recovery rate was higher, the improvement in ductility was not significant, and the non-recoverable creep compliance showed almost no improvement compared to old asphalt, resulting in unremarkable overall performance.

[0054] The experimental group and control group 7, using the same materials but with different treatment sequences, showed differences in five performance parameters. Overall, the experimental group's data were superior to control group 7. Control group 7 even had lower performance than the old asphalt group in two aspects: irreversible creep compliance, creep rate, and stiffness modulus ratio. BUDGE is prone to deterioration at room temperature due to reaction with moisture in the air. Aromatic oil is a highly hydrophobic and low-polarity oil with high compatibility with BUDGE. After mixing, the aromatic oil can protect BUDGE and slow down the deterioration rate. Pre-mixing aromatic oil and BUDGE forms a uniform aromatic oil film on the BUDGE surface, allowing the aromatic oil to penetrate the cross-linked network of the rubber powder during later mixing. This relaxes the rubber molecular chains, causes surface swelling, reduces the hardness and brittleness of the rubber powder, and enhances its fluidity. Furthermore, BUDGE has slightly weaker fluidity than aromatic oil; pre-mixing the two improves BUDGE's fluidity, ensuring uniform mixing on the rubber powder surface and better mixing with the degraded SBS in the asphalt after the addition of aged SBS-modified asphalt. The mixing method used in control group 7 would prevent BUDGE from performing optimally, leading to decreased stability of the final product and even precipitation, which would affect the concentration of the regenerator and the recycling efficiency of the old asphalt. Example 5: Fluorescence microscopy experiment.

[0055] Fluorescence microscopy can be used to observe the distribution of the internal polymer network in aged SBS-modified asphalt before and after regeneration. Fluorescence microscopy experiments were conducted on different groups of asphalt in Example 4, and the results are as follows: Figure 1 As shown, the fluorescence area decreased sharply after aging, indicating degradation of the polymer network. The fluorescence image area of ​​asphalt regenerated solely by aromatic oil, rubber powder, or BUDGE remained small, indicating that the regeneration effect of these three materials was not excellent. Adding a combination of two of these materials to aged SBS-modified asphalt increased the fluorescence area. When the reparative regenerator obtained according to this invention was added to aged SBS-modified asphalt, the corresponding regenerated asphalt fluorescence image area was larger and more uniformly distributed, demonstrating the superiority of the reparative rubber powder regenerator.

[0056] 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. A regenerator for repairing aged SBS modified asphalt, which is added to recycled SBS modified asphalt. It is prepared by first mixing aromatic oil with 1,4-butanediol diglycidyl ether, and then mixing with rubber powder. The weight parts of each component are: 3-8 parts aromatic oil, 0.5-2 parts 1,4-butanediol diglycidyl ether, and 8-10 parts rubber powder.

2. The aged SBS modified asphalt repair regenerator according to claim 1, wherein the aromatic oil is 4 parts, the 1,4-butanediol diglycidyl ether is 1 part, and the rubber powder is 10 parts.

3. The remediation rejuvenator for aged SBS modified asphalt according to claim 1, characterized in that: It also includes 0.1-0.3 parts sulfur powder and 0.1-0.45 parts polyvinyl alcohol.

4. The aged SBS modified asphalt repair regenerator according to claim 3, wherein the amount of sulfur powder is 0.1 parts and the amount of polyvinyl alcohol is 0.15 parts.

5. The preparation method of the aged SBS modified asphalt repair rejuvenator according to claim 1, comprising the following steps: S1. After recovering SBS modified bitumen, take 3-8 parts of aromatic oil and 0.5-2 parts of 1,4-butanediol diglycidyl ether and mix them at room temperature; S2. Take 8-10 parts of the adhesive powder, put it into 100℃ water and heat for 10 minutes, then remove and air dry to keep it dry; S3. Place the air-dried rubber powder in a 60℃ preheater for 5 minutes, stir the rubber powder at 1000 rpm, and then add the mixture of aromatic oil and 1,4-butanediol diglycidyl ether from S1 while stirring continuously, and continue stirring for 5 minutes. S4. Simultaneously add 0.1-0.2 parts sulfur powder and 0.15-0.3 parts polyvinyl alcohol, and stir at 1500 rpm for 5 minutes to obtain aged SBS modified asphalt repair regenerator.

6. The application of the aged SBS modified asphalt repair regenerator as described in claim 1 in the recycling and reuse of bridge deck and pavement materials.

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