Asphalt recycling agent suitable for hot-mixed recycled asphalt mixture and preparation method of asphalt recycling agent

Abstract

The invention relates to the technical field of recycling of asphalt pavement waste materials, in particular to an asphalt regenerant suitable for a hot-mixed recycled asphalt mixture and a preparation method of the asphalt regenerant. Wherein the mineral oil softens the aged asphalt, supplements lost light components in the aged asphalt and disperses other materials, and plays a continuous regeneration role in the regenerated asphalt mixture; the plasticizer improves the plasticity of the regenerated asphalt, so that the regenerated asphalt has better toughness, mechanical properties and impact resistance, and other materials are further dispersed under the synergistic effect of the plasticizer and the mineral oil; the anti-aging agent enhances the aging resistance and thermal stability of the recycled asphalt, and reduces the possibility of secondary aging of the recycled asphalt; the surfactant improves the interface state between the new asphalt and the old asphalt in the regenerated asphalt mixture, enhances the permeability of the regenerant and promotes mutual fusion of the new asphalt and the old asphalt; and the anti-stripping agent enhances the adhesion performance between the recycled asphalt and the aggregate, so that the recycled asphalt mixture has good thermal aging resistance and water damage resistance.

Description

Technical Field

[0001] The invention relates to the technical field of recycling and reusing waste asphalt pavement materials, and in particular to an asphalt regeneration agent suitable for hot-mix regenerated asphalt mixture and a preparation method thereof. Background Art

[0002] Asphalt pavement has the advantages of smooth surface without joints, comfortable driving, low vibration, low noise, wear resistance and short construction period, but it also has the obvious disadvantage of expensive asphalt. Under the influence of factors such as light, oxygen, temperature, humidity and load, asphalt gradually ages and hardens, resulting in cracks, collapse, degassing and large-scale cracking on the road surface. With the large-scale application of asphalt mixture in road engineering, roads built in the early stage also face the need for maintenance and repair. A large amount of maintenance and repair work is carried out every year for road diseases. Milling the road surface and paving new asphalt mixture is a common pavement maintenance method. Due to the large amount of road maintenance engineering, milling produces a large amount of recycled asphalt pavement (RAP material), and a large amount of new stone needs to be mined. The accumulation of RAP material will not only seriously waste land, but also produce harmful substances and endanger human health. In addition, asphalt resources are limited natural resources, and the accumulation and waste of them is not conducive to the sustainable use of resources. In order to renovate the road surface, it is inevitable to mine new asphalt and stone, which not only leads to a sharp reduction in non-renewable resources, but also seriously affects the ecological environment. Therefore, the reuse of RAP materials has broad prospects in practical applications.

[0003] The key to asphalt recycling technology is to mix the RAP material obtained by milling with new materials and regeneration agents to achieve the performance standards of conventional road use. According to the mixing temperature and site, asphalt concrete regeneration is mainly divided into hot regeneration in situ, hot regeneration in plant, cold regeneration in situ, cold regeneration in plant and warm regeneration. Hot regeneration in plant means that the old asphalt pavement is excavated and transported back to the mixing plant. After centralized crushing, the mix ratio is designed according to the quality requirements of different pavement layers, the addition ratio of the old asphalt mixture is determined, and the regeneration agent, new asphalt material, new aggregate, etc. are remixed in a mixer according to a certain proportion to form a new mixture, and the regenerated asphalt pavement is paved. Compared with other methods, hot regeneration in plant has become the most widely used recycling technology in my country due to its low cost, relatively low construction conditions and high economic benefits. However, hot regeneration in plant also has obvious disadvantages: on the one hand, the RAP material milled is not a regular aggregate, and the temperature is not easy to rise, resulting in a small amount of RAP material; on the other hand, the high construction mixing temperature may cause secondary aging of asphalt, affecting its performance and service life.

[0004] The key to hot regeneration in factory mix is ​​the use of regeneration agent. The main function of the regeneration agent is to restore the performance indicators of aged asphalt to their original state, while increasing the adhesion between the recycled asphalt and the aggregate, thereby resisting water damage, rutting and other diseases. Therefore, a good regeneration agent can significantly improve the performance of recycled asphalt. The ratio of new material, RAP material and regeneration agent is also particularly important. When the amount of RAP material is small, the purpose of secondary utilization of high-dosage RAP material cannot be achieved, and its performance is almost the same as that of new material; when the amount of RAP material is large, although the purpose of recycling RAP material is met, the performance of the asphalt mixture may not meet the standard. Therefore, under the condition of ensuring that the road performance is achieved, high-dosage RAP material should be used as much as possible. At the same time, the dosage of the regeneration agent must also be reasonable. If the regeneration agent is used excessively, the road performance of the asphalt mixture will exceed the applicable range; if the amount of regeneration agent used is insufficient, the aged asphalt cannot be completely regenerated, resulting in the road performance of the asphalt mixture not meeting the standard. Therefore, whether from the perspective of resource utilization, environmental protection or social and economic benefits, the research on high dosage of RAP materials is of great significance, and the development of an asphalt regeneration agent with excellent performance and low price is the top priority. Summary of the invention

[0005] In view of the technical problems in the prior art, the purpose of the present invention is to provide an asphalt regeneration agent suitable for hot-mix regenerated asphalt mixture, which solves the problem that the current asphalt regeneration agent has uneven regeneration effects and poor aging resistance, and at the same time effectively utilizes the RAP material generated during the road repair process, that is, the asphalt regeneration agent in the present invention has better compatibility with the RAP material, has excellent construction and workability, good aging resistance and excellent regeneration effect. At the same time, the present invention provides a preparation method thereof.

[0006] To achieve the above purpose, the technical solution provided by the present invention is:

[0007] An asphalt regeneration agent suitable for hot mix recycled asphalt mixture, comprising the following components in weight fractions:

[0008] 6-9 parts of mineral oil, 1-4 parts of plasticizer, 0.2-0.8 parts of anti-aging agent, 0.4-1 parts of surfactant and 0.4-1.2 parts of anti-stripping agent.

[0009] The present invention provides an asphalt regeneration agent suitable for hot mix recycled asphalt mixture. Compared with the asphalt regeneration agent in the prior art, the asphalt regeneration agent in the present invention is a solvent-based regeneration agent, which contains additives for asphalt regeneration agents such as mineral oil, plasticizers, anti-aging agents, surfactants and anti-stripping agents. This asphalt regeneration agent has a low viscosity at room temperature, indicating that it has excellent construction and workability, and can play a good penetration effect on aged asphalt; after being fused with aged asphalt, it was found through a rotary thin film oven test that the regenerated asphalt has a lower mass loss rate and rotational viscosity ratio, indicating that the regeneration agent can effectively improve the anti-aging properties of the regenerated asphalt and reduce the possibility of secondary aging of the regenerated asphalt; through a needle penetration test, it was found that the needle penetration of the regenerated asphalt was significantly higher than that of the aged asphalt, and close to the level of the base asphalt, indicating that the regeneration agent can effectively soften the aged asphalt and it has excellent permeability to the aged asphalt; Through the softening point test, it was found that the softening point of the regenerated asphalt was reduced and close to the level of the base asphalt, indicating that the degree of integration of the regenerator and the aged asphalt was high, which could effectively enhance the construction and workability of the aged asphalt; through the ductility test, it was found that the ductility of the regenerated asphalt was significantly improved or even slightly higher than that of the base asphalt, indicating that the addition of the regenerator effectively supplemented the light components lost inside the aged asphalt and enhanced the ductility of the aged asphalt, verifying the regeneration effect of the regenerator on the aged asphalt; through the cost analysis, it was found that the raw materials of the regenerator were cheap, and some of the raw materials came from the secondary utilization of bulk solid waste, which had good economic and environmental benefits. Therefore, the asphalt regenerator in the present invention has better compatibility with the RAP material, not only has excellent construction and workability, permeability and anti-aging properties, but also has excellent regeneration effect on the service performance of aged asphalt.

[0010] During the preparation process, it is first necessary to prepare the mineral oil and plasticizer into the base oil of the regeneration agent, and then mix the regeneration agent with an anti-aging agent, a surfactant and an anti-stripping agent to prepare an asphalt regeneration agent suitable for hot mix recycled asphalt mixture. The asphalt regeneration agent can ensure that the aged asphalt in the RAP material is softened and penetrated by the regeneration agent through the synergistic effect of the five materials, thereby replenishing the light components lost in the aged asphalt to a certain extent; this enables the regeneration agent and the RAP material to have good construction and workability at the initial mixing stage, ensuring the early strength of the recycled asphalt mixture. In particular, during long-term storage and transportation, the components in the regeneration agent can play a continuous regeneration role and reduce the possibility of secondary aging of the recycled asphalt, thereby realizing the recycling of RAP material in the recycled asphalt mixture.

[0011] Specifically, the mineral oil and plasticizer as the base oil of the asphalt regeneration agent can be used as dispersants to disperse the other three materials in the regeneration agent. At the same time, they can also be used to soften aged asphalt and replenish the light components lost in the aged asphalt, playing a continuous regeneration role in the regenerated asphalt mixture; the anti-aging agent as one of the components of the asphalt regeneration agent can reduce the possibility of secondary aging of the regenerated asphalt during mixing and paving at high temperatures, which is beneficial to enhance the anti-aging property of the regenerated asphalt mixture. In particular, the material used for the anti-aging agent comes from whiskers synthesized from bulk solid waste phosphogypsum. Its application in asphalt regeneration agent can not only effectively improve the service performance of the regenerated asphalt, but also recycle and reuse the phosphogypsum, which has significant economic benefits. Economic and environmental benefits; surfactants, as one of the components of asphalt regeneration agents, can enhance the compatibility of the regeneration agent with aged asphalt, help to restore the viscoelastic properties of aged asphalt, thereby improving the performance of the regenerated asphalt mixture, and can reduce the surface tension of the regeneration agent, promote the uniform distribution of the regeneration agent in the aged asphalt, and make the regeneration agent more effectively penetrate into the aged asphalt to achieve better regeneration effect; anti-stripping agent, as one of the components of asphalt regeneration agents, mainly forms a strong adhesion between asphalt and aggregate through physical adsorption or its unique chemical structure, so that the asphalt mixture has good resistance to heat aging and water damage, and ultimately achieves the purpose of effectively extending the service life of the road surface.

[0012] Based on the above technical solution, the mineral oil is naphthenic oil with a density of 0.95 g / cm 3 , 40℃ kinematic viscosity is 140mm 2 / s, flash point 185°C, pour point -33°C. The naphthenic oil is the base material for preparing the asphalt regeneration agent. When it works in synergy with the plasticizer, it can be used as a dispersant to disperse the other three materials in the asphalt regeneration agent. At the same time, it can also supplement the light components lost by the aged asphalt in the RAP material and soften the aged asphalt, playing a continuous regeneration role in the regenerated asphalt mixture.

[0013] On the basis of the above technical solution, the plasticizer is one or a mixture of dioctyl phthalate and dioctyl adipate. The plasticizer can improve the fluidity of the regeneration agent, making it easier to mix with the aged asphalt, so that it is evenly distributed in the entire asphalt mixture, and the regeneration effect is enhanced. In addition, the aged asphalt usually becomes hard and brittle and loses its original flexibility, while the plasticizer can soften the aged asphalt and restore its flexibility, thereby improving the crack resistance of the regenerated asphalt. At the same time, the plasticizer can also be used as a dispersant to disperse the other three materials in the asphalt regeneration agent under the synergistic effect of mineral oil, thereby further increasing the regeneration effect of the regeneration agent.

[0014] On the basis of the above technical scheme, the anti-aging agent is one or a mixture of phosphogypsum whiskers and tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester. In particular, phosphogypsum whiskers are waste products after secondary refining of industrial solid waste phosphogypsum, and its main component is calcium sulfate, which is non-toxic and has the advantages of high strength and high aspect ratio. The mechanism of action of phosphogypsum whiskers is to be evenly dispersed inside the asphalt under the synergistic effect of mineral oil and plasticizer, thereby forming a certain cross-linked network structure inside the asphalt and reinforcing the asphalt, and its excellent high temperature resistance can also enhance the asphalt structural stability while improving its anti-aging property, thereby ensuring that the regenerated asphalt has better anti-aging property. The mechanism of action of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester is that it contains multiple antioxidant groups in its molecular structure, which can provide multiple antioxidant protection effects, and the structure of pentaerythritol ester makes it have good dispersibility and durability in asphalt, and can play an anti-aging effect in a long-term and stable manner.

[0015] On the basis of the above technical solution, the surfactant is a mixture of one or two of non-ionic natural fatty alcohol and ethylene oxide adduct, isomeric fatty alcohol polyoxyethylene ether. The action mechanism of the surfactant is that it can enhance the compatibility of the regeneration agent with the aged asphalt, help to restore the viscoelastic properties of the aged asphalt, thereby improving the performance of the regenerated asphalt mixture, and it can reduce the surface tension of the regeneration agent, promote the uniform distribution of the regeneration agent in the aged asphalt, and make the regeneration agent more effectively penetrate into the aged asphalt to achieve a better regeneration effect.

[0016] On the basis of the above technical solution, the anti-stripping agent is one or a mixture of two or more of JW-AS1 type non-amine amphoteric active organic polymer compounds and ZZ-A2 type non-amine amphoteric active organic polymer compounds (relative molecular weight greater than 2000). It mainly forms a strong adhesion between asphalt and aggregate through physical adsorption or its unique chemical structure, so that the asphalt mixture has good heat aging resistance and water damage resistance, and finally achieves the purpose of effectively extending the service life of the road surface.

[0017] The method for preparing the asphalt regeneration agent suitable for hot mix regenerated asphalt mixture comprises the following steps:

[0018] Step 1, preparing premix A; mixing mineral oil and plasticizer evenly to obtain premix A;

[0019] Step 2, preparing mixture B; placing premix A in a constant temperature oil bath at 155-175° C., and shearing with a high-speed shearing machine at a speed of 1500-2500 rpm for 0.3-0.7 h to obtain a fully fused mixture B;

[0020] Step three, prepare asphalt regeneration agent; add antioxidant, surfactant and anti-stripping agent to mixture B in small amounts in sequence, and use a high-speed shearing machine to continuously shear and stir at a speed of 3500-4500rpm for 0.3-0.7h to obtain the final product, i.e., asphalt regeneration agent.

[0021] The beneficial effects of the technical solution provided by the present invention are:

[0022] 1. The present invention provides an asphalt regeneration agent suitable for hot-mix recycled asphalt mixture, which solves the problems of uneven regeneration effects, poor aging resistance and high prices of current asphalt regeneration agents. At the same time, it also effectively utilizes the RAP material generated during the road repair process, that is, the asphalt regeneration agent in the present invention has better compatibility with the RAP material, has excellent construction and workability, good aging resistance and excellent regeneration effect. Specifically, the mineral oil, as the base oil component of the additive for the regeneration agent, can not only soften the aged asphalt, but also replenish the light components lost in the aged asphalt and disperse the remaining materials, thereby playing a continuous regeneration role in the regenerated asphalt mixture; the plasticizer improves the plasticity of the regenerated asphalt, making it have better toughness, mechanical properties and impact resistance, and further disperses the remaining materials under the synergistic effect with the mineral oil; the anti-aging agent enhances the aging resistance and thermal stability of the regenerated asphalt, and reduces the possibility of secondary aging of the regenerated asphalt; the surfactant improves the interface state between the new and old asphalt in the regenerated asphalt mixture, enhances the penetration performance of the regeneration agent, and promotes the mutual fusion of the new and old asphalt; the anti-stripping agent enhances the adhesion performance between the regenerated asphalt and the aggregate through physical adsorption and its unique chemical structure, so that the regenerated asphalt mixture has good resistance to heat aging and water damage.

[0023] 2. At the same time, the present invention also provides a method for preparing the above-mentioned asphalt regeneration agent, which has a simple preparation process, convenient construction, and excellent practical performance. DETAILED DESCRIPTION

[0024] The specific implementation of the present invention is further described below in conjunction with the technical solution.

[0025] Example 1

[0026] An asphalt regeneration agent suitable for hot mix recycled asphalt mixture, comprising the following components in weight fractions:

[0027] 7 parts of cyclohexane oil, 3 parts of dioctyl phthalate, 0.2 parts of phosphogypsum whiskers, 0.4 parts of non-ionic natural fatty alcohol and ethylene oxide adduct and 0.4 parts of JW-AS1 type non-amine amphoteric active organic polymer compound.

[0028] The method for preparing the asphalt regeneration agent suitable for hot mix regenerated asphalt mixture comprises the following steps:

[0029] Step 1, preparing premix A; mixing accurately weighed naphthenic oil and dioctyl phthalate at room temperature to obtain premix A;

[0030] Step 2, preparing mixture B; placing premix A in a 160° C. constant temperature oil bath, and shearing with a high-speed shearing machine at a speed of 2000 rpm for 0.5 h to obtain a fully fused mixture B;

[0031] Step three, preparing an asphalt regeneration agent; adding phosphogypsum whiskers, non-ionic natural fatty alcohol and ethylene oxide adducts, and JW-AS1 non-amine amphoteric active organic polymer compounds to mixture B in sequence by multiple small additions, and continuously shearing and stirring at a speed of 4000 rpm for 0.5 h using a high-speed shearing machine to obtain the final product, i.e., the asphalt regeneration agent.

[0032] Example 2

[0033] An asphalt regeneration agent suitable for hot mix recycled asphalt mixture, comprising the following components in weight fractions:

[0034] 6 parts of cyclohexane oil, 4 parts of dioctyl adipate, 0.5 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 0.7 parts of non-ionic natural fatty alcohol and ethylene oxide adduct and 0.8 parts of JW-AS1 type non-amine amphoteric active organic polymer compound.

[0035] The method for preparing the asphalt regeneration agent suitable for hot mix regenerated asphalt mixture comprises the following steps:

[0036] Step 1, preparing premix A; stirring accurately weighed cyclohexane oil and dioctyl adipate at room temperature to obtain premix A;

[0037] Step 2, preparing mixture B; placing premix A in a 160° C. constant temperature oil bath, and shearing with a high-speed shearing machine at a speed of 1500 rpm for 0.3 h to obtain a fully fused mixture B;

[0038] Step three, preparing an asphalt regeneration agent; adding pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], a non-ionic natural fatty alcohol and ethylene oxide adduct, and a JW-AS1 type non-amine amphoteric active organic polymer compound to the mixture B in sequence by multiple small additions, and continuously shearing and stirring at a speed of 3500rpm for 0.7h using a high-speed shearing machine to obtain the final product, i.e., the asphalt regeneration agent.

[0039] Example 3

[0040] An asphalt regeneration agent suitable for hot mix recycled asphalt mixture, comprising the following components in weight fractions:

[0041] 8 parts of cyclohexane oil, 2 parts of dioctyl adipate, 0.8 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1 part of isomeric fatty alcohol polyoxyethylene ether and 1.2 parts of ZZ-A2 type non-amine amphoteric active organic polymer compound.

[0042] The method for preparing the asphalt regeneration agent suitable for hot mix regenerated asphalt mixture comprises the following steps:

[0043] Step 1, preparing premix A; stirring accurately weighed cyclohexane oil and dioctyl adipate at room temperature to obtain premix A;

[0044] Step 2, preparing mixture B; placing premix A in a 160° C. constant temperature oil bath, and shearing with a high-speed shearing machine at a speed of 2500 rpm for 0.5 h to obtain a fully fused mixture B;

[0045] Step three, preparing an asphalt regeneration agent; adding pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], isomeric fatty alcohol polyoxyethylene ether and ZZ-A2 type non-amine amphoteric active organic polymer compound to mixture B in sequence by multiple small additions, and continuously shearing and stirring at a speed of 4500rpm for 0.3h using a high-speed shearing machine to obtain the final product, i.e., the asphalt regeneration agent.

[0046] Example 4

[0047] An asphalt regeneration agent suitable for hot mix recycled asphalt mixture, comprising the following components in weight fractions:

[0048] 9 parts of naphthenic oil, 1 part of dioctyl phthalate, 0.5 parts of phosphogypsum whiskers, 1 part of isomeric fatty alcohol polyoxyethylene ether and 0.8 parts of ZZ-A2 type non-amine amphoteric active organic macromolecular compound.

[0049] The method for preparing the asphalt regeneration agent suitable for hot mix regenerated asphalt mixture comprises the following steps:

[0050] Step 1, preparing a premix A; stirring accurately weighed naphthenic oil and dioctyl phthalate at room temperature to obtain a premix A;

[0051] Step 2, preparing mixture B; placing premix A in a 160° C. constant temperature oil bath, and shearing with a high-speed shearing machine at a speed of 2000 rpm for 0.7 h to obtain a fully fused mixture B;

[0052] Step three, prepare asphalt regeneration agent; add phosphogypsum whiskers, isomerized fatty alcohol polyoxyethylene ether and ZZ-A2 type non-amine amphoteric active organic polymer compound to mixture B in sequence by multiple small additions, and use a high-speed shearing machine to continuously shear and stir at a speed of 3500rpm for 0.7h to obtain the final product, i.e., asphalt regeneration agent.

[0053] Example 5

[0054] An asphalt regeneration agent suitable for hot mix recycled asphalt mixture, comprising the following components in weight fractions:

[0055] 7 parts of cyclohexane oil, 3 parts of dioctyl phthalate, 0.8 parts of phosphogypsum whiskers, 1 part of isomeric fatty alcohol polyoxyethylene ether and 0.4 parts of JW-AS1 type non-amine amphoteric active organic polymer compound.

[0056] The method for preparing the asphalt regeneration agent suitable for hot mix regenerated asphalt mixture comprises the following steps:

[0057] Step 1, preparing a premix A; stirring accurately weighed naphthenic oil and dioctyl phthalate at room temperature to obtain a premix A;

[0058] Step 2, preparing mixture B; placing premix A in a 160° C. constant temperature oil bath, and shearing with a high-speed shearing machine at a speed of 2500 rpm for 0.5 h to obtain a fully fused mixture B;

[0059] Step three, prepare asphalt regeneration agent; add phosphogypsum whiskers, isomerized fatty alcohol polyoxyethylene ether and JW-AS1 type non-amine amphoteric active organic polymer compound to mixture B in sequence by multiple small additions, and use a high-speed shearing machine to continuously shear and stir at a speed of 4500rpm for 0.7h to obtain the final product, i.e., asphalt regeneration agent.

[0060] Comparative Example 1

[0061] Compared with Example 1, Comparative Example 1 did not add an anti-aging agent, and the remaining components and preparation methods were the same;

[0062] Comparative Example 2

[0063] Comparative Example 2 Compared with Example 2, no surfactant was added, and the remaining components and preparation methods were the same;

[0064] Comparative Example 3

[0065] Compared with Example 3, Comparative Example 3 does not add an anti-stripping agent, and the remaining components and preparation methods are the same.

[0066] Comparative Example 4

[0067] Compared with Example 4, Comparative Example 4 does not add mineral oil, and the remaining components and preparation methods are the same.

[0068] Experimental results and performance analysis

[0069] According to the "Highway Engineering Asphalt and Asphalt Mixture Test Procedure" JTG E20-2011, the samples of Examples 1-5 and Comparative Examples 1-3 were subjected to a rotating film oven test, and several tests were subjected to physical property tests, and the regeneration effect of the regeneration agent was measured by the needle penetration, elongation and softening point indicators. In addition, in order to further characterize the regeneration effect of the regeneration agent, 50% of the RAP material was mixed with 4% of the asphalt regeneration agent and a certain amount of new asphalt and new aggregate to prepare a regenerated asphalt mixture, and the dynamic stability, maximum failure strain and freeze-thaw splitting strength ratio of the regenerated asphalt mixture were tested by rutting test, beam bending test and freeze-thaw splitting test. The test results are shown in Tables 1 and 2.

[0070] Table 1 Test results of anti-aging property and regeneration effect of recycled asphalt

[0071] sample Mass loss rate / % Viscosity ratio Needle penetration / 0.1mm Softening point / ℃ 15℃ elongation / cm Example 1 0.91 1.31 74 48.5 91.3 Example 2 0.84 1.26 72 48.9 89.5 Example 3 0.86 1.27 78 47.8 93.7 Example 4 0.87 1.29 79 47.4 94.1 Example 5 0.85 1.26 74 48.3 91.6 Comparative Example 1 1.25 1.51 76 48.1 91.5 Comparative Example 2 0.86 1.27 70 49.2 89.1 Comparative Example 3 0.88 1.29 77 47.9 92.6 Comparative Example 4 1.21 1.41 62 53.5 71.1

[0072] A comparative analysis of the mass loss rate and viscosity ratio of Examples 1-5 and Comparative Examples 1-3 shows that: the mass loss rate of the prepared regenerated asphalt ranges from 0.84% ​​to 1.25%, and the viscosity ratio ranges from 1.26 to 1.51. The mass loss rate and viscosity of Example 2 of the present invention are relatively low. This is because it not only uses a higher amount of plasticizer, but also adds a high amount of anti-aging agent. The increase in the amount of plasticizer can effectively reduce the volatilization of asphalt during use, thereby improving its anti-aging performance, and the increase in the amount of anti-aging agent also further improves the anti-aging property of the regenerated asphalt; the mass loss rate and viscosity of Comparative Example 1 are relatively high. This is because no anti-aging agent is added compared with Example 1; but it should be noted that the addition of anti-aging agent will increase the viscosity of the regenerated asphalt while increasing the anti-aging property of the regenerated asphalt, and too much anti-aging agent is prone to uneven dispersion inside the asphalt and cause stress concentration, so the amount added should not be too much. The mass loss rate and viscosity ratio of the remaining embodiments and comparative examples are all within a reasonable range, which indicates that changes in the dosage of surfactants and anti-stripping agents will not cause significant changes in the anti-aging properties of the regenerated asphalt. Therefore, under the synergistic effect of mineral oil, plasticizer and anti-aging agent, the regenerated asphalt has suitable anti-aging properties, which effectively reduces the possibility of secondary aging of the regenerated asphalt during mixing, transportation and construction.

[0073] The regeneration effect of the regeneration agent on aged asphalt was evaluated by needle penetration test, softening point test and ductility test. A comparative analysis of the three indicators of Examples 1-5 and Comparative Examples 1-4 shows that when the ratio of mineral oil to plasticizer changes, the three indicators of the regenerated asphalt show an obvious fluctuation trend. This is because mineral oil and plasticizer, as the base oil of the regeneration agent, occupy an important proportion in the regeneration agent, and under the synergistic effect of the two, the aged asphalt is quickly softened and the light components lost inside it are gradually replenished, which eventually manifests as the restoration of service performance. Therefore, the ratio of mineral oil to plasticizer seriously affects the regeneration effect of the regeneration agent. In addition, it is found from Examples 2-3 and Comparative Examples 2-3 that surfactants and anti-stripping agents have a certain influence on the regeneration effect of the regeneration agent, but because the proportion of the two in the regeneration agent is low, the fluctuation range of the three indicators of the regenerated asphalt is also low. In particular, it can be found from Example 4 and Comparative Example 4 that mineral oil has a significant impact on the regeneration effect of the regeneration agent. This is because mineral oil is the main component of the regeneration agent and accounts for a large proportion. It has a softening effect on aged asphalt. Therefore, the fluctuation range of the three indicators of regenerated asphalt is more obvious.

[0074] Table 2 Road performance test results of recycled asphalt mixture

[0075] sample Dynamic stability / (times / mm) Maximum failure strain / με Freeze-thaw splitting strength ratio / % Example 1 4580 2830 84.1 Example 2 4620 2787 82.3 Example 3 4470 2861 84.9 Example 4 4360 2808 83.4 Example 5 4530 2845 84.3 Comparative Example 1 4560 2825 84.2 Comparative Example 2 4260 2627 79.8 Comparative Example 3 4290 2694 79.4 Comparative Example 4 4750 2360 74.3

[0076] In order to characterize the regeneration effect of the regeneration agent on the road performance of the regenerated asphalt mixture, the dynamic stability, maximum failure strain and freeze-thaw splitting strength ratio of the regenerated asphalt mixture were studied to evaluate its high temperature performance, low temperature performance and water stability. A comparative analysis of the dynamic stability, maximum failure strain and freeze-thaw splitting strength ratio of Examples 1-5 and Comparative Examples 1-4 shows that the initial strengths of Examples 1-5 and Comparative Examples 1-2 are both greater than 4000 times / mm, much higher than the 2400 times / mm specified in JTG F40-2004, indicating that although the change in the proportion of the components inside the regeneration agent will cause a certain volatility in the high temperature performance of the regenerated asphalt mixture, the fluctuation range is limited. This is because the dynamic stability of the regenerated asphalt mixture mainly comes from the RAP material inside it, which often has higher stiffness and deformation resistance, and can therefore provide significant high temperature deformation resistance for the regenerated asphalt mixture. In addition, it can be found that the maximum failure strains of Example 2 and Comparative Example 2-4 are significantly lower than 2800 με specified in JTG F40-2004; this is because compared with other examples, the mineral oil and plasticizer ratio in the regeneration agent used in Example 2 is the lowest, and the lower mineral oil ratio has a poor softening and penetration effect on the aged asphalt in the RAP material, which reduces the construction and workability of the regenerated asphalt mixture, and ultimately causes the attenuation of the crack resistance of the regenerated asphalt mixture at low temperatures. The difference between Comparative Example 2-4 and Example 2-4 is that the regeneration agent lacks surfactants, anti-stripping agents and mineral oil. The surfactant can enhance the compatibility of the regeneration agent with the aged asphalt, which helps to restore the viscoelastic properties of the aged asphalt, and it can reduce the surface tension of the regeneration agent, so that the regeneration agent can penetrate into the aged asphalt more effectively, achieving a better regeneration effect; the anti-stripping agent can form a strong adhesion between the new asphalt and the RAP material, so that the regenerated asphalt mixture has good heat aging resistance and water damage resistance; mineral oil, as the main component of the regeneration agent, softens and reduces the viscosity of the aged asphalt, thereby reducing the possibility of brittle fracture of the asphalt mixture. Since the regeneration agent used in Comparative Examples 2-4 lacks surfactant, anti-stripping agent and mineral oil, the prepared regeneration agent has poor penetration effect and regeneration effect on aged asphalt in RAP material, which eventually causes the attenuation of low temperature performance of regenerated asphalt mixture, while it can be found from Comparative Example 1 that the anti-aging agent does not cause significant changes in the low temperature performance of regenerated asphalt mixture. In addition, it can be found that the freeze-thaw splitting strength ratio of Comparative Examples 2-4 is significantly lower than 80% specified in JTG F40-2004; although the freeze-thaw splitting strength ratio of regenerated asphalt mixture in other embodiments and Comparative Example 1 is different due to the different proportions of components in the regeneration agent, the difference is not obvious.It can be found that when the ratio of mineral oil to plasticizer in the regeneration agent is reduced, the freeze-thaw splitting strength ratio will be adversely affected. This is because less mineral oil is difficult to soften the aged asphalt in the RAP material more comprehensively, and the degree of fusion between the regeneration agent and the RAP material cannot be effectively guaranteed, which will cause the water stability of the regenerated asphalt mixture to change. From Comparative Example 1 and Example 1, it can be found that the absence of an anti-aging agent in the regeneration agent does not cause a significant change in the freeze-thaw splitting strength ratio of the regenerated asphalt mixture, because the mechanism of action of the anti-aging agent is to improve the anti-aging performance of the regenerated asphalt, and its dispersion and interaction relationship inside the asphalt will not affect the water stability of the regenerated asphalt mixture. Comparative Examples 2-4 show that surfactants, anti-stripping agents and mineral oil have a significant effect on the water stability of the regenerated asphalt mixture. This is because surfactants can enhance the compatibility of regeneration agents with aged asphalt, promote the uniform distribution of regeneration agents in aged asphalt, and make regeneration agents more effectively penetrate into aged asphalt to achieve better regeneration effects; while anti-stripping agents can form strong adhesion between new asphalt and RAP materials in the regenerated asphalt mixture, so that the regenerated asphalt mixture has good resistance to water damage; mineral oil can soften the aged asphalt, improve the adhesion of the regenerated asphalt and reduce the possibility of brittle fracture of the asphalt mixture. Thus, the regenerated asphalt mixture has good resistance to water damage.

[0077] According to the performance test results of the above embodiments and comparative examples, the asphalt regeneration agent suitable for hot mix recycled asphalt mixture provided by the present invention has good construction and workability, and can improve the good anti-aging properties and regeneration effect of recycled asphalt and recycled asphalt mixture. According to the comparison results of mass loss rate and viscosity ratio, needle penetration, softening point, ductility, dynamic stability, maximum failure strain and freeze-thaw splitting strength ratio, it is found that mineral oil and plasticizer, as the base oil of asphalt regeneration agent, can be used as dispersants to disperse the other three materials in the regeneration agent. At the same time, they can also be used to soften aged asphalt and replenish the light components lost in aged asphalt, playing a continuous regeneration role in the regenerated asphalt mixture; anti-aging agent can reduce the possibility of secondary aging of regenerated asphalt during mixing and paving at high temperature, which is beneficial to enhance the anti-aging property of regenerated asphalt mixture; surfactant can enhance the compatibility of regeneration agent with aged asphalt, improve the performance of regenerated asphalt mixture, reduce the surface tension of regeneration agent, and make regeneration agent more effectively penetrate into aged asphalt to achieve better regeneration effect; anti-stripping agent can promote the formation of strong adhesion between asphalt and aggregate inside the regenerated asphalt mixture, so that the regenerated asphalt mixture has good heat aging resistance and water damage resistance, and finally achieve the purpose of effectively extending the service life of the road surface.

[0078] When designing asphalt regeneration agent, combined with the changing trends of multiple service performances of recycled asphalt and recycled asphalt mixture, it was found that the formula of asphalt regeneration agent needs to include four ingredients: mineral oil, plasticizer, anti-aging agent, surfactant and anti-stripping agent: 6-9 parts of mineral oil, 1-4 parts of plasticizer, 0.2-0.8 parts of anti-aging agent, 0.4-1 parts of surfactant and 0.4-1.2 parts of anti-stripping agent. The five materials can play a synergistic role to ensure the anti-aging and regeneration effect of the regeneration agent on aged asphalt in RAP material, and improve the service performance of recycled asphalt and recycled asphalt mixture.

Claims

1. An asphalt regeneration agent suitable for hot mix recycled asphalt mixture, characterized in that: The asphalt regeneration agent suitable for hot mix recycled asphalt mixture includes the following components by weight: 6-9 parts of mineral oil, 1-4 parts of plasticizer, 0.2-0.8 parts of anti-aging agent, 0.4-1 parts of surfactant and 0.4-1.2 parts of anti-stripping agent.

2. The asphalt regeneration agent suitable for hot mix regenerated asphalt mixture according to claim 1, characterized in that: The mineral oil is naphthenic oil.

3. The asphalt regeneration agent suitable for hot mix regenerated asphalt mixture according to claim 1, characterized in that: The plasticizer is one of dioctyl phthalate and dioctyl adipate or a mixture of the two.

4. The asphalt regeneration agent suitable for hot mix regenerated asphalt mixture according to claim 1, characterized in that: The anti-aging agent is one of phosphogypsum whiskers and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate or a mixture of two of them.

5. The asphalt regeneration agent suitable for hot mix regenerated asphalt mixture according to claim 1, characterized in that: The surfactant is a mixture of one or two of non-ionic natural fatty alcohol and ethylene oxide adduct, isomeric fatty alcohol polyoxyethylene ether.

6. The asphalt regeneration agent suitable for hot mix regenerated asphalt mixture according to claim 1, characterized in that: The anti-stripping agent is one or a mixture of two or more of W-AS1 type non-amine amphoteric active organic polymer compounds and ZZ-A2 type non-amine amphoteric active organic polymer compounds, and the relative molecular mass of the organic polymer compound is greater than 2000.

7. The method for preparing the asphalt regeneration agent suitable for hot mix regenerated asphalt mixture according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1, preparing premix A; mixing mineral oil and plasticizer evenly to obtain premix A; Step 2, preparing mixture B; placing premix A in a constant temperature oil bath at 155-175° C., and shearing with a high-speed shearing machine at a speed of 1500-2500 rpm for 0.3-0.7 h to obtain a fully fused mixture B; Step three, prepare asphalt regeneration agent; add antioxidant, surfactant and anti-stripping agent to mixture B in small amounts in sequence, and use a high-speed shearing machine to continuously shear and stir at a speed of 3500-4500rpm for 0.3-0.7h to obtain the final product, i.e., asphalt regeneration agent.