Chemically Reactive SBS Modified Asphalt Recycler and Formulation Design Method

Abstract

The present invention belongs to the technical field of asphalt pavement material regeneration, and specifically discloses a chemical reaction type SBS modified asphalt regeneration agent and a formula design method. The regeneration agent includes 6-10 parts of base oil, 1-2 parts of penetrant, 1-3 parts of molecular repair agent, and 0.01-0.05 parts of catalyst by mass; the base oil is waste edible vegetable oil, the penetrant is isooctyl alcohol polyoxyethylene ether, the molecular repair agent is hexamethylene diisocyanate, and the catalyst is dibutyltin dilaurate. The regeneration agent is used for the regeneration of aged SBS modified asphalt, and the ranking of the comprehensive performance of the regenerated asphalt is obtained by the TOPSIS method, and then the optimal regeneration agent formula and dosage are obtained, providing a scientific and reasonable reference for the efficient application of the regeneration agent.

Description

Technical Field

[0001] The invention belongs to the technical field of asphalt pavement material regeneration, and specifically relates to a chemical reaction type SBS modified asphalt regeneration agent and a formula design method. Background Art

[0002] SBS modified asphalt not only enhances the high temperature rutting resistance of the pavement, but also significantly improves its fatigue cracking resistance, low temperature cracking resistance and water damage resistance, thus achieving all-round optimization of asphalt pavement performance, and is therefore highly favored in high-strength pavement construction. However, as the service time increases, asphalt mixtures inevitably age under the influence of multiple factors such as vehicle load, high temperature, ultraviolet radiation, water, wind, acid rain and chloride corrosion.

[0003] SBS modified asphalt has a typical two-phase structure, and its aging process involves the hardening of the asphalt phase and the degradation of polymers. Specifically, the aging of the asphalt phase is manifested as the migration of the four components of asphalt, that is, the saturated and aromatic components are gradually converted into asphaltene and colloid; while the degradation of polymers refers to the reduction in the particle size of SBS particles and the oxidation and fracture of the polybutadiene block. Therefore, the regeneration of the aged SBS modified asphalt should also consider the regeneration of the asphalt phase and the regeneration of the SBS phase. Light oil is usually used for the regeneration of the asphalt phase, such as waste engine oil, aromatic oil, vegetable oil, waste cooking oil, etc. For the regeneration of the SBS phase, studies have found that isocyanates and diepoxy or triepoxy compounds can connect broken SBS. The road performance of aged SBS modified asphalt is comprehensively improved by regenerating the two-phase structure.

[0004] Selecting the appropriate dosage of regeneration agent is a crucial issue. Too high dosage may weaken the high-temperature anti-rutting performance and medium-temperature anti-fatigue performance of asphalt, while insufficient dosage may affect construction efficiency and low-temperature anti-cracking performance. At present, there is no unified standard for the selection of regeneration agent dosage. Most construction practices still rely on simple indicators such as needle penetration and softening point restored to unaged asphalt, but these methods often cannot fully reflect the performance of materials under long-term use and low-temperature environments. The method of ranking by close proximity to ideal solutions (TOPSIS) is a comprehensive evaluation method. By measuring the distance between each sample and the positive and negative ideal solutions, the relative closeness to the ideal solution is obtained, and the advantages and disadvantages of each alternative solution are ranked, thereby evaluating the comprehensive performance of each alternative solution. Applying the TOPSIS method to the selection of regeneration agent formula and dosage can provide a certain theoretical basis for the efficient regeneration of aged SBS modified asphalt. Summary of the invention

[0005] The purpose of the present invention is to provide a chemical reaction type SBS modified asphalt regeneration agent and a formulation design method, aiming to provide an optimal ratio scheme and optimal dosage of the regeneration agent, achieve efficient regeneration of aged SBS modified asphalt, and improve the recycling rate of pavement materials.

[0006] To achieve the above object, the first aspect of the present invention provides a chemical reaction type SBS modified asphalt regeneration agent, which comprises 6 to 10 parts of base oil, 1 to 2 parts of penetrant, 1 to 3 parts of molecular repair agent, and 0.01 to 0.05 parts of catalyst in parts by mass;

[0007] The base oil is waste edible vegetable oil, the penetrant is isooctyl alcohol polyoxyethylene ether, the molecular repair agent is hexamethylene diisocyanate, and the catalyst is dibutyltin dilaurate.

[0008] Preferably, the base oil is waste edible vegetable oil that has been purified by filtration, etc., and its main component is long-chain alkanes as determined by infrared spectroscopy. The catalyst can accelerate the reaction rate between the isocyanate group and the hydroxyl group or the carboxyl group.

[0009] In a second aspect, the present invention provides a method for preparing a chemical reaction type SBS modified asphalt regeneration agent, comprising the following steps:

[0010] S1, prepare base oil, penetrant, molecular repair agent and catalyst according to the mass fractions, and set them aside;

[0011] S2, mixing the base oil and the penetrant, stirring at a speed of 200 to 500 rpm for 3 to 5 minutes to obtain Agent A;

[0012] S3, mixing the molecular repair agent and the catalyst, stirring at a speed of 200 to 500 rpm for 3 to 5 minutes, to obtain agent B.

[0013] In a third aspect, a method for designing a formula of a chemical reaction type SBS modified asphalt regeneration agent based on the TOPSIS method is provided, characterized in that the method comprises the following steps:

[0014] S1', using the regeneration agent obtained by the preparation method of claim 2 to prepare regenerated SBS modified asphalt with different regeneration agent dosages, as an alternative; the regenerated SBS modified asphalt includes unaged SBS modified asphalt and aged SBS modified asphalt and the regeneration agent;

[0015] S2', select performance indicators and construct an evaluation matrix X; the performance indicators include high, medium and low temperature performance indicators, where high temperature refers to >45°C, medium temperature refers to 0-45°C, and low temperature refers to <0°C;

[0016] S3', performing data forward processing and normalization processing on the evaluation matrix X to obtain a matrix Y;

[0017] S4', use the entropy weight method to calculate the objective weight of each indicator in the matrix Y;

[0018] S5', calculate the correct solution set A+ and negative ideal solution set A - ;

[0019] S6', calculate the positive ideal solution distance D + and negative ideal solution distance D - , as well as the relative proximity, and rank the comprehensive performance of recycled SBS modified asphalt;

[0020] S7', by comparing the comprehensive ranking of the alternative schemes with the unaged SBS modified asphalt, the optimal regeneration agent ratio and dosage are obtained.

[0021] Further, in S1', the preparation of the regenerated SBS modified asphalt comprises the following steps:

[0022] The molten unaged SBS modified asphalt and the aged SBS modified asphalt are mixed, and firstly agent B is added thereto, and stirred at 1000-1500 rpm and 165°C for 10 minutes, and then agent A is added thereto, and stirred at 1000-1500 rpm and 165°C for 20-30 minutes to obtain regenerated SBS modified asphalt.

[0023] Furthermore, the mass ratio of the unaged SBS modified asphalt to the aged SBS modified asphalt is (5-8):3, preferably 7:3.

[0024] Furthermore, the aged SBS modified asphalt is obtained by first aging the unaged SBS modified asphalt in a rotary film oven at 163° C. for 85 minutes and then aging it in a pressure aging container at 100° C. and 2.1 MPa for 20 hours.

[0025] Furthermore, the addition amount of the chemical reaction type SBS modified asphalt regeneration agent is 1% to 15% of the mass of the aged SBS modified asphalt, preferably 4% to 12%.

[0026] Furthermore, in S2', the performance index includes high, medium and low temperature performance indexes, wherein the high temperature performance index is the irreversible creep compliance J at 3.2 kPa. nr 3.2, Medium temperature performance index is selected as fatigue life under 5% strain N f 5%, the low temperature performance index is selected from the bending beam rheological test results at -12°C. Since the stiffness modulus S value is less than 300MPa, the creep rate m is preferred;

[0027] The expression of the evaluation matrix X is:

[0028]

[0029] In the formula, x ip represents the Pth index of the ith alternative;

[0030] In S3', the following formula is used to process extremely small data in a positive direction:

[0031]

[0032] Among them, max refers to the maximum value of the data in this column; x i Refers to the i-th data in this column.

[0033] The evaluation matrix X is normalized, and the formula is as follows:

[0034]

[0035] And thus we get the matrix Y:

[0036]

[0037] Further, in S4', the entropy weight method includes the following steps:

[0038] (1) Calculate the entropy value of the jth indicator:

[0039]

[0040] Where k = 1 / ln(n)>0, satisfying e j ≥0; p ij It is the proportion of each sample value to the total value under the same index. y ij is the i-th data of the j-th indicator.

[0041] (2) Calculate the information utility value:

[0042] d j =1-e j ,j=1,2,…,p

[0043] (3) Calculate the weight of each indicator:

[0044]

[0045] Among them, ω j is the weight of the jth indicator; d j is the information utility value of the j-th indicator;

[0046] In S5', the positive ideal solution set A is calculated according to the following formula + and negative ideal solution set A - :

[0047] Positive ideal solution set:

[0048] Negative ideal solution set:

[0049] In S6', the positive ideal solution distance D + and negative ideal solution distance D - Calculated according to the following formula:

[0050] Positive ideal solution distance:

[0051] Negative ideal solution distance:

[0052] The relative proximity is calculated according to the following formula:

[0053]

[0054] Among them, C i Indicates the relative closeness of the ith alternative. Used to evaluate comprehensive performance, C i The larger the value, the better the overall performance of the corresponding alternative.

[0055] The present invention also provides a method for preparing regenerated SBS modified asphalt, comprising: mixing unaged SBS modified asphalt and aged SBS modified asphalt in a molten state, first adding agent B thereto, stirring at 1000-1500 rpm and 165° C. for 10 min, then adding agent A, stirring at 1000-1500 rpm and 165° C. for 20-30 min, to obtain regenerated SBS modified asphalt; the mass ratio of the unaged SBS modified asphalt to the aged SBS modified asphalt is (5-8):3, preferably 7:3, and the dosage of the regeneration agent (the sum of agent A and agent B) is 12% of the mass of the aged SBS modified asphalt.

[0056] Compared with the prior art, the beneficial results and advantages of the present invention are as follows:

[0057] (1) The chemical reaction type SBS modified asphalt regeneration agent provided by the present invention targets the two-phase structure of SBS modified asphalt, utilizes the long-chain alkanes rich in the base oil, supplements the light components in the aged SBS modified asphalt, and realizes component adjustment. The molecular repair agent is hexamethylene diisocyanate, which can connect the broken SBS through the interaction of the isocyanate group with -OH and -COOH, thereby realizing the reconstruction of the SBS disconnected structure. The penetrant in the regeneration agent can enhance the diffusion ability of the regeneration agent to the aged asphalt, accelerate the reduction of the viscosity of the aged asphalt, and thus enable the new and old asphalt to be mixed evenly.

[0058] (2) The formula design method of the chemical reaction type SBS modified asphalt regeneration agent based on the TOPSIS method provided by the present invention adopts a comprehensive performance evaluation method, which can take into account the high, medium and low temperature performance of the regeneration agent applied to aged SBS modified asphalt, making the application of the regeneration agent more reasonable and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 The preparation flow chart of the chemical reaction type SBS modified asphalt regeneration agent provided by the present invention;

[0060] Figure 2 The present invention provides a flow chart for the implementation of the regeneration agent ratio and dosage selection method based on the TOPSIS method. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] In the following examples and comparative examples, the linear SBS mass content in the unaged SBS modified asphalt used is 4%, wherein the base asphalt is Shell 70# road petroleum base asphalt, and the linear SBS is YH-791E produced by Sinopec Baling Chemical Co., Ltd. In the laboratory, a rotary film oven was used to simulate short-term aging at 163°C for 85 minutes, and then a pressure aging container was used to simulate long-term aging at 100°C and 2.1MPa for 20 hours to obtain an aged SBS modified asphalt for subsequent tests. Waste edible vegetable oil was provided by Zhonglu Qiming Transportation Technology Co., Ltd., and the molecular repair agent was hexamethylene diisocyanate, which was provided by Shanghai McLean Biochemical Technology Co., Ltd. The catalyst was dibutyltin dilaurate, which was provided by Shanghai Aladdin Biochemical Technology Co., Ltd.

[0063] Example 1

[0064] A regenerated SBS modified asphalt, the preparation method comprises the following steps:

[0065] (1) Weigh 8 parts of waste edible vegetable oil and 2 parts of isooctyl alcohol polyoxyethylene ether by mass, add them into the same container, and stir them at 300 rpm for 5 minutes to obtain agent A;

[0066] (2) Weigh 1 part of hexamethylene diisocyanate and 0.01 part of dibutyltin dilaurate by mass, add them into another container, and stir them at 300 rpm for 5 minutes to obtain Agent B;

[0067] (3) Weigh 70 parts of the above-mentioned unaged SBS modified asphalt and 30 parts of aged SBS modified asphalt in a molten state and add them to a stirring tank, first add agent B thereto and stir at 1500 rpm and 165°C for 10 minutes, then add agent A to the stirring tank and stir at 1500 rpm and 165°C for 20 minutes to obtain regenerated SBS modified asphalt. The total mass of agent A and agent B is 4% of the mass of aged SBS modified asphalt (agent A and agent B are added at a mass ratio of 10:1.01, that is, the mass ratio of waste edible vegetable oil, polyoxyethylene isooctyl alcohol ether, hexamethylene diisocyanate and dibutyltin dilaurate is 8:2:1:0.01).

[0068] Example 2

[0069] A regenerated SBS modified asphalt, the preparation method comprises the following steps:

[0070] (1) Weigh 8 parts of waste edible vegetable oil and 2 parts of isooctyl alcohol polyoxyethylene ether by mass, add them into the same container, and stir them at 300 rpm for 5 minutes to obtain agent A;

[0071] (2) Weigh 1 part of hexamethylene diisocyanate and 0.01 part of dibutyltin dilaurate by mass, add them into another container, and stir them at 300 rpm for 5 minutes to obtain Agent B;

[0072] (3) Weigh 70 parts of the above unaged SBS modified asphalt and 30 parts of aged SBS modified asphalt in a molten state and add them to a stirring kettle, first add agent B thereto and stir at 1500 rpm and 165°C for 10 min, then add agent A to the stirring kettle and stir at 1500 rpm and 165°C for 20 min to obtain regenerated SBS modified asphalt. The total mass of agent A and agent B is 8% of the mass of aged SBS modified asphalt (agent A and agent B are added at a mass ratio of 10:1.01).

[0073] Example 3

[0074] A regenerated SBS modified asphalt, the preparation method comprises the following steps:

[0075] (1) Weigh 8 parts of waste edible vegetable oil and 2 parts of isooctyl alcohol polyoxyethylene ether by mass, add them into the same container, and stir them at 300 rpm for 5 minutes to obtain agent A;

[0076] (2) Weigh 1 part of hexamethylene diisocyanate and 0.01 part of dibutyltin dilaurate by mass, add them into another container, and stir them at 300 rpm for 5 minutes to obtain Agent B;

[0077] (3) Weigh 70 parts of the above unaged SBS modified asphalt and 30 parts of aged SBS modified asphalt in a molten state and add them to a stirring kettle, first add agent B thereto and stir at 1500 rpm and 165°C for 10 min, then add agent A to the stirring kettle and stir at 1500 rpm and 165°C for 20 min to obtain regenerated SBS modified asphalt. The total mass of agent A and agent B is 12% of the mass of aged SBS modified asphalt (agent A and agent B are added at a mass ratio of 10:1.01).

[0078] Comparative Example 1

[0079] Comparative Example 1 provides unaged SBS modified asphalt, which serves as a basis for selecting the optimal dosage of the regeneration agent.

[0080] Comparative Example 2

[0081] (1) Weigh 8 parts of waste edible vegetable oil and 2 parts of isooctyl alcohol polyoxyethylene ether by mass, add them into the same container, and stir them at 300 rpm for 5 minutes to obtain agent A;

[0082] (2) Weigh 70 parts of the above unaged SBS modified asphalt and 30 parts of aged SBS modified asphalt in a molten state and add them into a stirring kettle, add Agent A into the stirring kettle and stir at 1500 rpm and 165° C. for 20 minutes to obtain regenerated SBS modified asphalt. The amount of Agent A added is 4% of the mass of the aged SBS modified asphalt.

[0083] Comparative Example 3

[0084] (1) Weigh 8 parts of waste edible vegetable oil and 2 parts of isooctyl alcohol polyoxyethylene ether by mass, add them into the same container, and stir them at 300 rpm for 5 minutes to obtain agent A;

[0085] (2) Weigh 70 parts of the above unaged SBS modified asphalt and 30 parts of aged SBS modified asphalt in a molten state and add them into a stirring kettle, add agent A into the stirring kettle and stir at 1500 rpm and 165° C. for 20 minutes to obtain regenerated SBS modified asphalt. The amount of agent A added is 8% of the mass of the aged SBS modified asphalt.

[0086] Comparative Example 4

[0087] (1) Weigh 8 parts of waste edible vegetable oil and 2 parts of isooctyl alcohol polyoxyethylene ether by mass, add them into the same container, and stir them at 300 rpm for 5 minutes to obtain agent A;

[0088] (2) Weigh 70 parts of the above unaged SBS modified asphalt and 30 parts of aged SBS modified asphalt in a molten state and add them into a stirring kettle, add Agent A into the stirring kettle and stir at 1500 rpm and 165° C. for 20 minutes to obtain regenerated SBS modified asphalt. The amount of Agent A added is 12% of the mass of the aged SBS modified asphalt.

[0089] Next, the entropy weight-TOPSIS method is used to conduct a comprehensive performance evaluation of the above candidate solutions. The steps are as follows:

[0090] (1) With reference to the "Testing Procedure for Asphalt and Asphalt Mixtures for Highway Engineering JTGE20-2011", the regenerated SBS modified asphalt obtained in the above examples and comparative examples was tested for high, medium and low temperature rheological properties using a dynamic shear rheometer and a bending beam rheometer, wherein high temperature refers to >45°C, medium temperature refers to 0-45°C, and low temperature refers to <0°C. Specifically, it includes a multi-stress repeated creep recovery test, a linear amplitude sweep test and a bending beam rheological test, and the relevant parameters are calculated. Since the stiffness modulus S value is less than 300MPa, the creep rate m is preferred.

[0091] (2) Select performance indicators, listed in Table 1, and construct the evaluation matrix X based on them.

[0092] Table 1 Performance indicators of alternative solutions

[0093]

[0094]

[0095] (3) Perform data normalization to obtain the matrix Y.

[0096]

[0097] The processing formula is as follows:

[0098]

[0099] (4) The objective weight of each indicator is calculated using the entropy weight method. The results are shown in Table 2.

[0100] The entropy weight method comprises the following steps:

[0101] (1) Calculate the entropy value of the jth indicator:

[0102]

[0103] Where k = 1 / ln(n)>0, satisfying e j ≥0; p ij It is the proportion of each sample value to the total value under the same index. y ijis the i-th data of the j-th indicator;

[0104] (2) Calculate the information utility value:

[0105] d j =1-e j ,j=1,2,…,p

[0106] (3) Calculate the weight of each indicator:

[0107]

[0108] Among them, ω j is the weight of the jth indicator; d j is the information utility value of the j-th indicator.

[0109] Table 2 Calculation results of entropy weight method

[0110] Performance Indicators Information entropy value e Information utility value d Weight (%) high temperature 0.849 0.151 18.171 Medium temperature 0.531 0.469 56.403 Low temperature 0.788 0.212 25.426

[0111] (5) Calculate the positive ideal solution set A according to the following formula + and negative ideal solution set A - :

[0112] Positive ideal solution set:

[0113] Negative ideal solution set:

[0114] In S6', the positive ideal solution distance D + and negative ideal solution distance D - Calculated according to the following formula:

[0115] Positive ideal solution distance:

[0116] Negative ideal solution distance:

[0117] The relative proximity is calculated according to the following formula:

[0118]

[0119] Among them, C i represents the relative closeness of the ith alternative. The results are shown in Table 3.

[0120] Table 3 TOPSIS calculation results

[0121]

[0122]

[0123] Table 1 shows the representative indicators of the rheological properties of the examples and comparative examples at high, medium and low temperatures. nr 3.2 The larger the value, the worse the high temperature rutting resistance of the asphalt material; N f The larger the m is, the better the medium-temperature fatigue cracking resistance of the asphalt material is; the larger the m is, the better the stress relaxation ability of the asphalt material is and the better the low-temperature cracking resistance is. The formulas of Examples 1, 2, and 3 are the same but the dosage of the regeneration agent is different. It can be found that with the increase of the dosage, the J of the regenerated asphalt increases. nr 3.2 gradually increases, N f The significant increase of 5% indicates that the increase of the amount of the regeneration agent of the present invention reduces the high-temperature anti-rutting performance and improves the medium-temperature anti-fatigue performance.

[0124] Comparison between Example 1, Example 2 and Example 3 and Comparative Example 1 shows that the regeneration agent of the present invention has excellent regeneration effect. The high temperature anti-rutting performance of the example can be restored to the level of Comparative Example 1 when the dosage is 4%. As the dosage increases, the high temperature anti-rutting performance gradually decreases. When the dosage reaches 8%, the high temperature anti-rutting performance is worse than that of Comparative Example 1. The medium temperature performance is better than that of Comparative Example 1 at 4%, but the low temperature stress relaxation ability of the example is worse than that of Comparative Example 1. Comparative Examples 2, 3 and 4 have the same formula but different dosages. Comparison of the three shows that as the dosage increases, the high temperature anti-rutting performance of the comparative example deteriorates, the low temperature anti-cracking performance is improved, and the medium temperature anti-fatigue performance first improves and then deteriorates. Comparing Comparative Examples 2, 3, and 4 with Comparative Example 1, it is found that the high-temperature anti-rutting performance and low-temperature anti-cracking performance of the first three are inferior to those of Comparative Example 1; the medium-temperature fatigue life will gradually increase when the dosage is 4% to 8%. At 8%, the medium-temperature fatigue life is greater than that of Comparative Example 1, but at 12%, the medium-temperature fatigue life is less than 8% and lower than that of Comparative Example 1, indicating that the higher dosage of the comparative example has an adverse effect on the medium-temperature fatigue resistance.

[0125] Comparing Example 1 with Comparative Example 2, Example 2 with Comparative Example 3, and Example 3 with Comparative Example 4, it is found that under the same dosage, J nr 3.2 lower than comparative example 4, N f 5% is much larger than that of comparative example 4, indicating that the high temperature anti-rutting performance and medium temperature fatigue performance of the embodiment are better than those of comparative example 4. However, at the same dosage, m of the embodiment is slightly smaller than that of the comparative example, indicating that the embodiment has limited improvement on the low temperature performance of aged SBS modified asphalt. The difference between Examples 1, 2, 3 and Comparative Examples 2, 3, and 4 is whether they contain molecular repair agents and catalysts, indicating that molecular repair agents and catalysts play an important role in the regeneration of SBS modified asphalt, especially in the significant improvement of medium temperature fatigue performance. This is because the molecular repair agent can efficiently connect the degraded SBS, thereby realizing the repair of the network structure in the aged asphalt, so the fatigue performance is significantly improved.

[0126] Table 2 is the calculation result of the entropy weight method. It can be found that the weight of the medium-temperature performance index is 56.403%, which is much larger than the weight of the high-temperature and low-temperature indexes. This is because the regeneration agent of the present invention can significantly improve the fatigue life of the aged SBS modified asphalt, so the numerical dispersion of the fatigue life is very large. Therefore, the weight of the medium-temperature performance index is much higher than that of the high-temperature and low-temperature indexes.

[0127] From the results of TOPSIS calculation in Table 3, the ranking of comprehensive performance of regenerated asphalt can be obtained. It can be found that among several alternatives, the comprehensive performance of Example 3 is the best. Comparative Example 1 is unaged SBS modified asphalt, and its comprehensive ranking is 2. Only the comprehensive performance of Example 3 is better than that of Comparative Example 1, indicating that when the dosage of the regeneration agent of the present invention is 12%, the comprehensive performance of the regenerated asphalt can be better than that of the unaged SBS modified asphalt, and the best regeneration effect can be achieved. Among Comparative Examples 2 to 4, Comparative Example 3 has the highest comprehensive ranking, that is, the comprehensive performance of the comparative example is the best when the dosage of the regeneration agent A is 8%, but it is still inferior to Comparative Example 1, so its regeneration effect on the aged SBS modified asphalt is limited and cannot be restored to the unaged state.

[0128] The above embodiments are only for illustrating the technical concept and features of the present invention. The purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing regenerated SBS modified asphalt, comprising the following steps: The molten unaged SBS modified asphalt and the aged SBS modified asphalt are mixed, and the B agent is first added thereto, and stirred at 1000-1500 rpm and 165° C. for 10 minutes, and then the A agent is added thereto, and stirred at 1000-1500 rpm and 165° C. for 20-30 minutes to obtain the regenerated SBS modified asphalt; The mass ratio of the unaged SBS modified asphalt to the aged SBS modified asphalt is 7:3, and the total amount of the agent A and the agent B is 12% of the mass of the aged SBS modified asphalt; The preparation methods of the A and B agents are as follows: S1. Prepare 8 parts of base oil, 2 parts of penetrant, 1 part of molecular repair agent, and 0.01 parts of catalyst for standby use; the base oil is waste edible vegetable oil, the penetrant is isooctyl alcohol polyoxyethylene ether, the molecular repair agent is hexamethylene diisocyanate, and the catalyst is dibutyltin dilaurate; S2, mixing the base oil and the penetrant, stirring at a speed of 200 to 500 rpm for 3 to 5 minutes, to obtain Agent A; S3, mixing the molecular repair agent and the catalyst, stirring at a speed of 200-500 rpm for 3-5 minutes to obtain agent B; The process of obtaining the total dosage of the A agent and the B agent being 12% of the mass of the aged SBS modified asphalt comprises the following steps: S1', using a regeneration agent composed of agent A and agent B to prepare regenerated SBS modified asphalt with different regeneration agent dosages as an alternative; the regenerated SBS modified asphalt includes unaged SBS modified asphalt and aged SBS modified asphalt and the regeneration agent; the mass ratio of the unaged SBS modified asphalt to the aged SBS modified asphalt is 7:3; S2', select performance indicators and construct an evaluation matrix X; the performance indicators include high, medium and low temperature performance indicators, where high temperature refers to >45°C, medium temperature is 0-45°C, and low temperature is <0°C; the high temperature performance indicator selects the irrecoverable creep compliance J under 3.2kPa nr 3.2, Medium temperature performance index is selected as fatigue life under 5% strain N f 5%, the low temperature performance index is selected from the bending beam rheological test results at -12℃, that is, the creep rate m; S3', performing data normalization processing on the evaluation matrix X to obtain a matrix Y; S4', use the entropy weight method to calculate the objective weight of each indicator in the matrix Y; S5', calculate the correct solution set A + and negative ideal solution set A - ; S6', calculate the positive ideal solution distance D + and negative ideal solution distance D - , and relative proximity, and rank the comprehensive performance of recycled SBS modified asphalt; S7', by comparing the relative closeness of the alternative schemes with the unaged SBS modified asphalt, the regeneration agent dosage in the alternative scheme with the largest relative closeness is the optimal regeneration agent dosage.

2. The preparation method according to claim 1, wherein the aged SBS modified asphalt is obtained by first aging the unaged SBS modified asphalt in a rotary thin film oven at 163° C. for 85 min and then aging it in a pressure aging container at 100° C. and 2.1 MPa for 20 h.

3. The preparation method according to claim 1, characterized in that: In S2', the expression of the evaluation matrix X is: In the formula, x ip represents the Pth index of the ith alternative; In S3', the following formula is used to process extremely small data in a positive direction: Among them, max refers to the maximum value of the data in this column; x i Refers to the i-th data in this column; The evaluation matrix X is normalized, and the formula is as follows: And thus we get the matrix Y:

4. The preparation method according to claim 1, characterized in that: In S4', the entropy weight method includes the following steps: (1) Calculate the entropy value of the jth indicator: Where k = 1 / ln(n)>0, satisfying e j ≥0; p ij It is the proportion of each sample value to the total value under the same index. y ij is the i-th data of the j-th indicator; (2) Calculate the information utility value: d j =1-e j ,j=1,2,…,p… (3) Calculate the weight of each indicator: Among them, ω j is the weight of the jth indicator; d j is the information utility value of the j-th indicator; In S5', the positive ideal solution set A is calculated according to the following formula + and negative ideal solution set A - : Positive ideal solution set: Negative ideal solution set: In S6', the positive ideal solution distance D + and negative ideal solution distance D - Calculated according to the following formula: Positive ideal solution distance: Negative ideal solution distance: The relative proximity is calculated according to the following formula: Among them, C i represents the relative closeness of the ith alternative.

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