Recovery and regeneration process based on old asphalt pavement material

Abstract

The invention discloses a recycling and regenerating process based on an old material of an asphalt pavement, and belongs to the technical field of asphalt pavement regeneration, the recycling and regenerating process comprises the following steps: S1, heating and uniformly stirring epoxy resin and petroleum asphalt, then adding a reactive diluent and an accelerant, and uniformly stirring to obtain an epoxy component; s2, stirring and heating the isocyanate tripolymer to a constant temperature, slowly dropwise adding the cardanol, after the cardanol is completely dropwise added, keeping the temperature, carrying out a reaction, and completely reacting the isocyanate tripolymer with the cardanol to obtain a blocked isocyanate tripolymer; s3, mixing the blocked isocyanate tripolymer with an epoxy component to obtain a cementing material; s4, stirring and heating the old graded asphalt material, then heating the cementing material, continuing to stir uniformly, paving the mixture on the pavement, leveling, compacting and curing to form a recycled asphalt pavement; the utilization rate of old asphalt pavement resources can be increased, and the mechanical strength of the recycled asphalt pavement can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of asphalt pavement regeneration, and in particular to a recycling process based on old asphalt pavement materials. Background Art

[0002] The paving of asphalt pavement requires a large amount of non-renewable resources such as petroleum asphalt and sand and gravel materials. Recycling and reusing old asphalt pavement materials can reduce the demand for new asphalt materials, which is of great significance for protecting limited natural resources and promoting sustainable development.

[0003] At present, there are two main ways to regenerate asphalt pavement. One is to heat and loosen the asphalt pavement on site, then add new asphalt, regeneration agent and new stone, and then mix and pave it on site through combined regeneration equipment to form a regenerated asphalt pavement. The other is to transport the old asphalt pavement materials recovered by milling back to the asphalt mixing site, reheat and mix them, add new asphalt and new stone to form a new hot mix asphalt mixture, and then use conventional asphalt concrete construction methods to pave and compact it to form a regenerated asphalt pavement. However, it is usually necessary to add more new asphalt, new stone and other materials to the regenerated asphalt pavement, and the utilization rate of old asphalt pavement materials is still low.

[0004] Based on the above situation, a Chinese patent document with publication number CN101845227A discloses a common asphalt regeneration agent and its preparation and application. The common asphalt regeneration agent is mainly prepared by heating, mixing and stirring base asphalt, regenerated oil, plasticizer and high-temperature stabilizer; the specific preparation method is: firstly heat the base asphalt at 115℃~135℃, then heat the regenerated oil, plasticizer and high-temperature stabilizer at 115℃~135℃ and stir to obtain a mixture, finally stir the base asphalt and the mixture at 115℃~135℃, and cool to obtain the common asphalt regeneration agent; when using, first take the aged asphalt and heat it at 110℃~135℃, then add the common asphalt regeneration agent thereto, the added amount is more than 30% of the amount of the aged asphalt, and then stir at a temperature of 100℃~110℃ to obtain the regenerated asphalt.

[0005] The above patent document discloses a method for making regenerated asphalt using aged asphalt. The method is to prepare a common asphalt regeneration agent with base asphalt, regenerated oil, plasticizer and high-temperature stabilizer, and then mix it with aged asphalt to form regenerated asphalt. The regenerated asphalt can form a new asphalt pavement after conventional asphalt pavement paving operations. However, the amount of common asphalt regeneration agent added must be more than 30% of the amount of aged asphalt. A large amount of new materials need to be consumed in the recycling process of asphalt pavement, and the utilization rate of old asphalt pavement materials is not high. Therefore, the method of regenerating asphalt still has room for improvement. Summary of the invention

[0006] In view of the technical defects existing in the background technology, the present invention proposes a recycling process based on old asphalt pavement materials, which solves the above technical problems and meets the actual needs. The specific technical solution is as follows: A recycling process based on old asphalt pavement materials, comprising the following steps: S1. Adding epoxy resin and petroleum asphalt into a stirring kettle, heating and stirring evenly, then adding active diluent and accelerator, stirring evenly and cooling to room temperature to obtain epoxy component; S2, adding isocyanate trimer into a reactor and heating and stirring, after the isocyanate trimer is heated to a constant temperature, slowly dripping cardanol into the reactor through a dropping funnel, and after the dropwise addition of cardanol is completed, keeping the temperature to react, and the isocyanate trimer in the reactor completely reacts with cardanol to obtain a blocked isocyanate trimer; S3, after the blocked isocyanate trimer is cooled to room temperature, it is mixed with the epoxy component to obtain a bonding material; S4. The old asphalt pavement material is crushed and screened to obtain graded asphalt old material, the graded asphalt old material is stirred and heated, and then the binder material is heated. After continuing to stir evenly, the mixture is spread on the road surface, and then leveled, compacted, and solidified to form a recycled asphalt pavement.

[0007] As a further technical solution of the present invention, the epoxy component includes the following components by mass percentage: 70% to 85% epoxy resin, 5% to 15% petroleum asphalt, 5% to 15% active diluent, and 0.5% to 1% accelerator.

[0008] As a further technical solution of the present invention, during the process of the isocyanate trimer and cardanol reacting in the reactor while being kept warm, the content of isocyanate groups in the product in the reactor is detected at regular intervals, and when the mass percentage of the isocyanate group is less than 0.05%, it is determined that the isocyanate trimer and cardanol in the reactor have completely reacted.

[0009] As a further technical solution of the present invention, in step S2, the temperature at which the isocyanate trimer is heated in the reactor is 70-80°C, and the temperature at which the isocyanate trimer and cardanol are kept warm in the reactor for reaction is 70-90°C for 1-4h.

[0010] As a further technical solution of the present invention, the isocyanate trimer is selected from hexamethylene diisocyanate trimer, isophorone diisocyanate trimer or a mixture of the two.

[0011] As a further technical solution of the present invention, in step S2, the mass ratio of the hexamethylene diisocyanate trimer to cardanol is 1:(0.6~0.7).

[0012] As a further technical solution of the present invention, in step S2, the mass ratio of the isophorone diisocyanate trimer to cardanol is 1:(0.5-0.6).

[0013] As a further technical solution of the present invention, in step S3, the mass ratio of the blocked isocyanate trimer to the epoxy component is 1:(1.5-2).

[0014] As a further technical solution of the present invention, in step S4, the heating temperature of the asphalt waste material is 120-140°C; The regenerated asphalt pavement includes the following components by mass percentage: 93% to 98% of old asphalt material and 2% to 7% of bonding material.

[0015] As a further technical solution of the present invention, the epoxy resin is selected from one or more of E20 epoxy resin, E44 epoxy resin, and E51 epoxy resin; The petroleum asphalt is selected from 70# petroleum asphalt, 90# petroleum asphalt, or a mixture of the two; The active diluent is selected from one or more of C12-14 alkyl glycidyl ether, butyl glycidyl ether, and benzyl glycidyl ether; The accelerator is γ-glycidyloxypropyltrimethoxysilane.

[0016] The beneficial effects of the present invention are: The present invention uses a binder and old asphalt materials as raw materials to produce regenerated asphalt, and a blocked isocyanate trimer is used as a cross-linking agent in the binder, so that the binder requires a higher temperature to cross-link and solidify, thereby improving the convenience of the binder in daily storage and transportation, and can improve the bonding strength of the binder and the toughness after curing, which is beneficial to improving the mechanical strength of the regenerated asphalt pavement. In addition, the present invention does not require component analysis of old asphalt materials and has a high utilization rate of old asphalt materials, simplifies the regeneration operation of old asphalt materials and efficiently recycles old asphalt pavement resources. DETAILED DESCRIPTION

[0017] The implementation mode of the present invention is described below in conjunction with relevant embodiments. The implementation mode of the present invention is not limited to the following embodiments, and the present invention relates to relevant necessary components in the technical field, which should be regarded as the known technology in the technical field and can be known and mastered by the technical personnel in the technical field.

[0018] A recycling process based on old asphalt pavement materials, comprising the following steps: S1. Adding epoxy resin and petroleum asphalt into a stirring kettle, heating and stirring evenly, then adding active diluent and accelerator, stirring evenly and cooling to room temperature to obtain epoxy component; S2, adding isocyanate trimer into a reactor and heating and stirring, after the isocyanate trimer is heated to a constant temperature, slowly dripping cardanol into the reactor through a dropping funnel, and after the dropwise addition of cardanol is completed, keeping the temperature to react, and the isocyanate trimer in the reactor completely reacts with cardanol to obtain a blocked isocyanate trimer; S3, after the blocked isocyanate trimer is cooled to room temperature, it is mixed with the epoxy component to obtain a bonding material; S4. The old asphalt pavement material is crushed and screened to obtain graded asphalt old material, the graded asphalt old material is stirred and heated, and then a binder is added. After continuing to stir evenly, the mixture is spread on the road surface and then leveled, compacted, and solidified to form a recycled asphalt pavement.

[0019] The asphalt pavement waste material of the present invention is obtained by planing and milling old asphalt pavement. The asphalt pavement waste material is crushed and screened to form asphalt waste materials of different sizes. These asphalt waste materials can be divided into four grades according to their sizes, namely, larger than 10mm, 10-5mm, 5-1mm, and smaller than 1mm. The four grades of asphalt waste materials are mixed in appropriate proportions to obtain graded asphalt waste materials. In the graded asphalt waste materials, the mass percentages of asphalt waste materials with sizes larger than 10mm, 10-5mm, 5-1mm, and smaller than 1mm are 35%-45%, 25%-35%, 15%-25%, and 5%-15%, respectively. The graded asphalt waste materials obtained by mixing asphalt waste materials of different sizes through reasonable grading can be better filled with small particles of asphalt waste materials into the gaps between large particles of asphalt waste materials, which is beneficial to improving the compactness inside the regenerated asphalt pavement and the mechanical strengths such as compressive strength and tensile strength, and can also improve the uniformity of solid mixing after the graded asphalt waste materials are mixed with the binder.

[0020] The adhesive material of the present invention is obtained by mixing a blocked isocyanate trimer as a cross-linking agent with an epoxy component. The isocyanate groups in the blocked isocyanate trimer are blocked by cardanol, so that they can remain stable under certain conditions and do not react with the epoxy resin, thereby improving the convenience of the adhesive material in daily storage and transportation. The adhesive material can restore its reaction activity by unblocking when a reaction is required. The unblocking temperature of the blocked isocyanate trimer is 120° C. When the temperature rises to above 120° C., the isocyanate groups in the blocked isocyanate trimer will restore their reaction activity, and the curing of the epoxy resin will be promoted by a cross-linking reaction. The binder component formed by the curing reaction of the closed isocyanate trimer and the epoxy resin has excellent bonding strength and toughness, which is beneficial to improving the mechanical strength of the regenerated asphalt pavement. In addition, due to the presence of a large number of polar hydroxyl groups in cardanol, it has a good wettability for the graded asphalt old materials, which is beneficial for the binder to evenly wrap the graded asphalt old materials. The granular graded asphalt old materials are adhered to each other through the binder to form regenerated asphalt. After the regenerated asphalt is evenly spread on the base surface of the pavement, it is leveled and compacted to form the prototype of the regenerated asphalt pavement. After the closed isocyanate trimer and the epoxy component are cured, the regenerated asphalt forms a solid whole, thereby obtaining a solid regenerated asphalt pavement.

[0021] It needs to be further explained that the medium-graded asphalt materials in recycled asphalt are mainly wrapped with binder materials and then cured by heating and cross-linking. Therefore, there is no need to consider operations such as oil, colloid, asphalt content analysis when traditional asphalt materials are recycled. It is only necessary to crush, screen and grade the asphalt materials, which is of positive significance to the promotion and application of efficient utilization of old recycled asphalt pavement resources.

[0022] As one of the preferred embodiments of the present invention, the epoxy component includes the following components by mass percentage: 70% to 85% epoxy resin, 5% to 15% petroleum asphalt, 5% to 15% active diluent, and 0.5% to 1% accelerator; the epoxy resin is selected from one or more of E20 epoxy resin, E44 epoxy resin, and E51 epoxy resin; the petroleum asphalt is selected from one or a mixture of 70# petroleum asphalt and 90# petroleum asphalt; the active diluent is selected from one or more of C12-14 alkyl glycidyl ether, butyl glycidyl ether, and benzyl glycidyl ether; the accelerator is γ-glycidyloxypropyl trimethoxysilane.

[0023] In the epoxy component of the present invention, the epoxy resin has excellent mechanical properties, chemical properties and thermal stability, and can significantly improve the shear resistance, cementation, adhesion and elastic modulus of the regenerated asphalt pavement, thereby making the regenerated asphalt pavement more stable and durable. During the curing process of the regenerated asphalt, the epoxy resin can undergo a cross-linking curing reaction with the isocyanate to form a stable network structure and serve as the basis for ensuring the strength of the regenerated asphalt pavement.

[0024] Furthermore, petroleum asphalt is the main film-forming substance of recycled asphalt. After forming a film, it will cover the surface of graded asphalt old material, playing a role of isolation and protection. Petroleum asphalt itself has excellent waterproof properties, which can effectively prevent the penetration of water and improve the waterproof performance of recycled asphalt pavement. Petroleum asphalt can resist the erosion of chemical substances, so that the recycled asphalt pavement has a certain resistance to corrosive substances such as acids, alkalis and salts.

[0025] Furthermore, active diluents can reduce the viscosity of epoxy resin, improve operability and reduce construction difficulty, making recycled asphalt easier to process and handle. Active diluents not only play a dilution role, but also participate in the cross-linking and curing reaction of epoxy resin and isocyanate, becoming a part of the cured product network structure, thereby improving the mechanical properties, adhesion and flexibility of the recycled asphalt pavement.

[0026] Furthermore, the accelerator can accelerate the cross-linking and curing reaction between epoxy resin and isocyanate, shorten the curing time and improve the processing efficiency. By adding an appropriate amount of accelerator, the progress and degree of the cross-linking and curing reaction can be regulated, thereby obtaining a regenerated asphalt pavement with higher performance.

[0027] As one of the preferred embodiments of the present invention, during the reaction of the isocyanate trimer and the cardanol in the reactor while being kept warm, the content of the isocyanate group of the product in the reactor is detected at regular intervals, and when the mass percentage of the isocyanate group is less than 0.05%, it is determined that the isocyanate trimer and the cardanol in the reactor have completely reacted; in order to determine whether the isocyanate trimer and the cardanol in the reactor have completely reacted, the isocyanate group content of the substance in the reactor is usually detected every 10 min, 15 min, 20 min or 30 min after the reaction is kept warm for 1 hour. The detection method can usually be chemical titration or chromatography. When the isocyanate group content is detected to be lower than 0.05%, it means that most of the isocyanate trimer in the reactor has completed the blocking reaction, and only a very small amount of isocyanate trimer remains that has not completed the blocking reaction. This part of isocyanate trimer will not cause the recycled asphalt to solidify at room temperature. Therefore, it can be regarded that the isocyanate trimer in the reactor has completely reacted with cardanol, the reactor can be cooled to terminate the reaction, and a highly pure blocked isocyanate trimer can be obtained from the reactor.

[0028] As one of the preferred embodiments of the present invention, in step S2, the temperature at which the isocyanate trimer is heated in the reactor is 70-80°C, and the temperature at which the isocyanate trimer and cardanol are kept warm in the reactor for reaction is 70-90°C, and the insulation time is 1-4h; during the blocking reaction of the isocyanate trimer and cardanol in the reactor, heating the isocyanate trimer can promote its activation and ensure the normal progress of the blocking reaction, and slowly adding cardanol can control the rate of the blocking reaction to avoid excessively violent reaction, which may lead to a decrease in product quality or the generation of by-products. Subsequently, the unreacted isocyanate trimer and cardanol continue to react by keeping warm to ensure that the two react fully, thereby improving the purity and quality of the product.

[0029] As one of the preferred embodiments of the present invention, the isocyanate trimer is selected from hexamethylene diisocyanate trimer, isophorone diisocyanate trimer, or a mixture of the two; hexamethylene diisocyanate trimer has good weather resistance and is not easily affected by environmental factors such as light and temperature to cause yellowing or degradation. The coating or material formed after the hexamethylene diisocyanate trimer is cured usually has high hardness and adhesion, and exhibits good wear resistance and chemical resistance. These excellent physical properties enable the hexamethylene diisocyanate trimer to provide excellent strength and durability in recycled asphalt; isophorone diisocyanate trimer has excellent thermal stability, can maintain stable performance under high temperature conditions, is not prone to degradation or failure, and exhibits good reactivity and cross-linking properties during the cross-linking and curing reaction between isophorone diisocyanate trimer and isocyanate, which helps to form a tight and solid structure in the recycled asphalt and improve the overall strength and stability.

[0030] As one of the preferred embodiments of the present invention, in step S2, the mass ratio of hexamethylene diisocyanate trimer to cardanol is 1:(0.6~0.7); the mass ratio of isophorone diisocyanate trimer to cardanol is 1:(0.5~0.6); in the process of preparing the blocked isocyanate trimer, the addition amount of isocyanate trimer and cardanol needs to adopt a suitable addition ratio to ensure that the isocyanate trimer can react completely after the blocking reaction, avoid the blocked isocyanate trimer containing more unblocked isocyanate groups, thereby avoiding the curing phenomenon of the bonding material during storage or transportation at room temperature.

[0031] As one of the preferred embodiments of the present invention, in step S3, the mass ratio of the blocked isocyanate trimer to the epoxy component is 1:(1.5~2); the mixing ratio of the blocked isocyanate trimer and the epoxy component needs to be controlled within a reasonable range to ensure that the blocked isocyanate trimer can completely undergo cross-linking and curing reaction with the epoxy resin, thereby improving the utilization rate of the raw materials.

[0032] As one of the preferred embodiments of the present invention, in step S4, the heating temperature of the old asphalt material is 120~140℃. Heating the old asphalt material can soften the asphaltene inside it and increase its fluidity, thereby making it easier to mix evenly with the binder. Heating can also promote the regeneration of asphaltene in the old asphalt material, so that it can restore or partially restore its original adhesion, flexibility and other properties. The regenerated asphalt pavement includes the following components in mass percentage: 93%~98% of old asphalt material and 2%~7% of binder. A large amount of old asphalt material is added to the regenerated asphalt pavement, which improves the utilization rate of the old asphalt material and is conducive to the recycling of resources.

[0033] In summary, the present invention uses a binder and old asphalt materials as raw materials to produce regenerated asphalt, and a closed isocyanate trimer is used as a cross-linking agent in the binder, so that the binder requires a higher temperature to cross-link and cure, thereby improving the convenience of the binder in daily storage and transportation, and can improve the bonding strength of the binder and the toughness after curing, which is beneficial to improving the mechanical strength of the regenerated asphalt pavement. In addition, the present invention does not require component analysis of old asphalt materials and has a high utilization rate of old asphalt materials, which simplifies the regeneration operation of old asphalt materials and efficiently recycles old asphalt pavement resources.

[0034] The present invention is further described below by way of examples and comparative examples.

[0035] Example 1

[0036] S1. Add E20 epoxy resin and 70# petroleum asphalt into a stirring kettle, heat to 50°C and stir evenly, then add C12-14 alkyl glycidyl ether and γ-glycidyloxypropyl trimethoxysilane and stir evenly, then cool to room temperature to obtain an epoxy component; The epoxy component includes the following components by mass percentage: E20 epoxy resin 80%, 70# petroleum asphalt 105%, C12-14 alkyl glycidyl ether 9%, γ-glycidyl ether oxypropyl trimethoxy silane 1%; S2, adding hexamethylene diisocyanate trimer to a reactor, stirring and heating to 75°C, and after the hexamethylene diisocyanate trimer is heated to a constant temperature, slowly dripping cardanol into the reactor through a dropping funnel, and keeping the temperature at 80°C for reaction after the cardanol is added after 40 minutes. After keeping the temperature for reaction for 1 hour, the content of isocyanate groups in the product in the reactor is detected at regular intervals. When the mass percentage of isocyanate groups is less than 0.05%, it is determined that the hexamethylene diisocyanate trimer and cardanol in the reactor have completely reacted. After the hexamethylene diisocyanate trimer and cardanol in the reactor are completely reacted, a blocked hexamethylene diisocyanate trimer is obtained; In the reactor, the mass ratio of hexamethylene diisocyanate trimer to cardanol was 1:0.65; S3, after the blocked hexamethylene diisocyanate trimer is cooled to room temperature, it is mixed with the epoxy component at a mass ratio of 1:1.75 to obtain a bonding material; S4, crushing and screening the old asphalt pavement material to obtain graded asphalt old material, stirring the graded asphalt old material and heating it to 135° C., adding a binder, continuing to stir evenly, spreading the mixture on the road surface, and then leveling, compacting, and curing to form a regenerated asphalt pavement; The recycled asphalt pavement includes the following components by mass percentage: 98% old asphalt material and 2% binder.

[0037] Example 2

[0038] The difference between this embodiment and the above-mentioned embodiment 1 is that in step S4, the regenerated asphalt pavement includes the following components in percentage by mass: 95.5% of old asphalt material and 4.5% of binder material, and the remaining operations are the same as the raw material components.

[0039] Example 3

[0040] The difference between this embodiment and the above-mentioned embodiment 1 is that in step S4, the regenerated asphalt pavement includes the following components in percentage by mass: 93% of old asphalt material and 7% of binder material, and the remaining operations are the same as the raw material components.

[0041] Example 4

[0042] S1. Add E20 epoxy resin and 70# petroleum asphalt into a stirring kettle, heat to 50°C and stir evenly, then add C12-14 alkyl glycidyl ether and γ-glycidyloxypropyl trimethoxysilane and stir evenly, then cool to room temperature to obtain an epoxy component; The epoxy component includes the following components by mass percentage: E20 epoxy resin 80%, 70# petroleum asphalt 105%, C12-14 alkyl glycidyl ether 9%, γ-glycidyl ether oxypropyl trimethoxy silane 1%; S2, adding hexamethylene diisocyanate trimer to a reactor, stirring and heating to 75°C, and after the hexamethylene diisocyanate trimer is heated to a constant temperature, slowly dripping cardanol into the reactor through a dropping funnel, and keeping the temperature at 80°C for reaction after the cardanol is added after 40 minutes. After keeping the temperature for reaction for 1 hour, the content of isocyanate groups in the product in the reactor is detected at regular intervals. When the mass percentage of isocyanate groups is less than 0.05%, it is determined that the hexamethylene diisocyanate trimer and cardanol in the reactor have completely reacted. After the hexamethylene diisocyanate trimer and cardanol in the reactor are completely reacted, a blocked hexamethylene diisocyanate trimer is obtained; In the reactor, the mass ratio of hexamethylene diisocyanate trimer to cardanol was 1:0.65; S3, after the blocked hexamethylene diisocyanate trimer is cooled to room temperature, it is mixed with the epoxy component at a mass ratio of 1:1.75 to obtain a bonding material; S4, heating the paraffin until it is melted, adding iron powder and a paraffin-specific emulsifier, and stirring evenly, then adding a sodium chloride solution, an inorganic salt stabilizer, and an alcohol emulsifier, and then emulsifying the sodium chloride solution wrapped in paraffin through a common emulsification operation, stirring the emulsion while gradually cooling the emulsion, the paraffin will gradually solidify to form granular oxygen-absorbing particles, the shell of the oxygen-absorbing particles is composed of paraffin and iron powder, and the interior is wrapped with a sodium chloride solution; Among them, the addition amount of paraffin-specific emulsifier, inorganic salt stabilizer, and alcohol emulsifier is appropriately added based on the current common paraffin emulsification process. The number of carbon atoms in paraffin is 30. In the oxygen-absorbing particles, the mass ratio of paraffin, iron powder, and sodium chloride solution is 1:0.5:1.5, and the concentration of sodium chloride solution is 2%; S5. After crushing and screening the old asphalt pavement materials, the graded asphalt old materials are obtained. The graded asphalt old materials are stirred and heated to 135° C., and then a binder and oxygen-absorbing particles are added. After further stirring, the mixture is spread on the pavement, and then leveled, compacted, and solidified to form a regenerated asphalt pavement. The recycled asphalt pavement includes the following components by mass percentage: 94.5% old asphalt material, 4.5% binder, and 1% oxygen-absorbing particles.

[0043] Comparative Example 1 Based on Example 6 in the specification of the Chinese patent document Common Asphalt Rejuvenator and Its Preparation and Application (Publication No.: CN101845227A), a regenerated asphalt with a regeneration agent blending ratio of 30.6% is prepared. The regenerated asphalt is spread on the road surface and then leveled, compacted and cured to form a regenerated asphalt pavement.

[0044] It should be noted that, for the same graded asphalt waste materials in all the above embodiments and comparative examples, the mass percentages of asphalt waste materials with sizes greater than 10 mm, 10-5 mm, 5-1 mm, and less than 1 mm in the graded asphalt waste materials are 38%, 30%, 20%, and 12%, respectively.

[0045] Based on the standard document "Regenerated Asphalt Concrete" (GB / T 25033-2010), the regenerated asphalt of all the above embodiments and comparative examples was tested for void ratio, stability, flow value, dynamic stability, residual stability of Marshall test after immersion in water, residual strength ratio of freeze-thaw splitting test, and failure strain index of low-temperature bending test. The test results are shown in Table 1 below.

[0046]

[0047] Table 1 According to the data in Table 1, various performance indicators of Example 1, Example 2 and Example 3 based on the technical solution of the present invention all meet the technical requirements of regenerated asphalt, and various performance indicators of Comparative Example 1 also meet the technical requirements of regenerated asphalt. A certain performance indicator in Comparative Example 1 is close to that in Example 1 or Example 2 or Example 3. It can be seen that the technical solution of the present invention and the technical solution of Comparative Example 1 can both recycle and regenerate old asphalt materials well and apply them to regenerated asphalt pavements; however, it should be noted that 30.6% of regeneration agent is added to Comparative Example 1, and its utilization rate of old asphalt materials is low. Comparative Example 1 needs to consume more new raw materials to obtain technical effects close to those of the technical solution of the present invention. The technical solution of the present invention can improve the utilization rate of old asphalt materials and reduce the production cost of regenerated asphalt pavements.

[0048] Furthermore, Example 4 adds oxygen-absorbing particles on the basis of Example 1. During the paving and gradual solidification of the regenerated asphalt pavement, the high temperature will melt the paraffin shell of the oxygen-absorbing particles, so that the iron powder can contact the sodium chloride solution. The electrolyte environment provided by the sodium chloride causes the iron powder, water, and oxygen to react in a high temperature environment to generate iron hydroxide. The reaction occurs inside the regenerated asphalt pavement. The reaction consumes the oxygen in the internal voids of the regenerated asphalt pavement, causing a negative pressure to form inside the voids, so that the regenerated asphalt pavement can be better compacted and the internal porosity can be reduced. The deeper the voids in the regenerated asphalt pavement, the lower the possibility of the voids being connected to the outside world, and the better the effect of the negative pressure formed by the voids at these locations. Therefore, the oxygen-absorbing particles can more efficiently reduce the porosity deep in the regenerated asphalt pavement. After the porosity inside the regenerated asphalt pavement is reduced, its technical indicators and mechanical properties will be better.

[0049] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A recycling process based on old asphalt pavement materials, characterized in that: The following steps are involved: S1. Adding epoxy resin and petroleum asphalt into a stirring kettle, heating and stirring evenly, then adding active diluent and accelerator, stirring evenly and cooling to room temperature to obtain epoxy component; S2, adding isocyanate trimer into a reactor and heating and stirring, after the isocyanate trimer is heated to a constant temperature, slowly dripping cardanol into the reactor through a dropping funnel, and after the dropwise addition of cardanol is completed, keeping the temperature to react, and the isocyanate trimer in the reactor completely reacts with cardanol to obtain a blocked isocyanate trimer; S3, after the blocked isocyanate trimer is cooled to room temperature, it is mixed with the epoxy component to obtain a bonding material; S4. The old asphalt pavement material is crushed and screened to obtain graded asphalt old material, the graded asphalt old material is stirred and heated, and then the binder material is heated. After continuing to stir evenly, the mixture is spread on the road surface, and then leveled, compacted, and solidified to form a recycled asphalt pavement.

2. The recycling process based on asphalt pavement waste materials according to claim 1 is characterized in that: The epoxy component includes the following components by mass percentage: 70% to 85% epoxy resin, 5% to 15% petroleum asphalt, 5% to 15% active diluent, and 0.5% to 1% accelerator.

3. The recycling process based on asphalt pavement waste materials according to claim 1 is characterized in that: During the process of the isocyanate trimer and cardanol reacting in the reactor while being kept warm, the content of isocyanate groups in the product in the reactor is detected at regular intervals. When the mass percentage of the isocyanate group is less than 0.05%, it is determined that the isocyanate trimer and cardanol in the reactor have completely reacted.

4. The recycling process based on asphalt pavement waste materials according to claim 1 is characterized in that: In step S2, the temperature at which the isocyanate trimer is heated in the reactor is 70-80° C., and the temperature at which the isocyanate trimer and cardanol are kept warm in the reactor for reaction is 70-90° C. for 1-4 hours.

5. The recycling process based on asphalt pavement waste materials according to claim 1 is characterized in that: The isocyanate trimer is selected from hexamethylene diisocyanate trimer and isophorone diisocyanate trimer, or a mixture of the two.

6. The recycling process based on asphalt pavement waste materials according to claim 5 is characterized in that: In step S2, the mass ratio of the hexamethylene diisocyanate trimer to cardanol is 1:(0.6-0.7).

7. The recycling process based on asphalt pavement waste materials according to claim 5 is characterized in that: In step S2, the mass ratio of the isophorone diisocyanate trimer to cardanol is 1:(0.5-0.6).

8. The recycling process based on asphalt pavement waste materials according to claim 1 is characterized in that: In step S3, the mass ratio of the blocked isocyanate trimer to the epoxy component is 1:(1.5-2).

9. The recycling process based on asphalt pavement waste materials according to claim 1 is characterized in that: In step S4, the heating temperature of the asphalt waste material is 120-140°C; The regenerated asphalt pavement includes the following components by mass percentage: 93% to 98% of old asphalt material and 2% to 7% of bonding material.

10. The recycling process based on asphalt pavement waste materials according to claim 1 is characterized in that: The epoxy resin is selected from one or more of E20 epoxy resin, E44 epoxy resin, and E51 epoxy resin; The petroleum asphalt is selected from 70# petroleum asphalt, 90# petroleum asphalt, or a mixture of the two; The active diluent is selected from one or more of C12-14 alkyl glycidyl ether, butyl glycidyl ether, and benzyl glycidyl ether; The accelerator is γ-glycidyloxypropyltrimethoxysilane.

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