A method for recycling waste asphalt road surface

Abstract

The present invention relates to a method for recycling waste pavement asphalt, and specifically provides a method for recycling waste pavement asphalt without a regeneration agent. The recycling method uses crushed pavement asphalt milling material, new asphalt, new aggregate, and fiber that have been crushed and screened multiple times, controls the temperature of each reaction process and the way in which the new asphalt is introduced, realizes the use of a large amount of recycled asphalt pavement materials, and does not use a regeneration agent, effectively realizes the reuse of waste asphalt, reduces the cost of road maintenance or paving, and has high economic and environmental benefits.

Description

Technical Field

[0001] The invention relates to the field of highway asphalt pavement construction materials, and in particular to a method for recycling waste asphalt pavement materials. Background Art

[0002] Asphalt pavement is used for 80% of my country's first-class highways and expressways due to its good driving comfort and road performance. Although the design service life of general asphalt mixture pavement is 15 years, there will be some quality defects during pavement construction. At the same time, the pavement will be affected and acted upon by various factors such as changes in high and low temperature external environment, ultraviolet radiation, water scouring, oil corrosion, vehicle overloading, etc., which will cause the asphalt pavement to be damaged to varying degrees and various road performances to deteriorate prematurely. Most asphalt pavements need to be repaired after 3 to 5 years of use, and some even earlier; some asphalt pavements need to be overhauled after 8 years of use.

[0003] Generally, the damage of asphalt pavement is mainly concentrated in the surface layer. When repairing it, the main method is planing and re-paving, that is, the surface layer of the original asphalt mixture pavement is milled, and then new asphalt mixture is spread as the surface layer. This planing and re-paving method will produce a large amount of waste asphalt mixture. According to statistics, the annual amount of waste asphalt mixture on highways alone has reached 2.2 million tons, and this number will increase at a rate of 15% per year. For these waste asphalt mixtures that have been milled, if they are simply discarded, they will not only occupy a large amount of land, but also cause pollution to the surrounding environment; at the same time, the mining of a large amount of new stones will also bring about serious ecological damage such as vegetation destruction and soil erosion. The recycling of asphalt mixture is an economical, environmentally friendly, and sustainable road repair technology that meets the requirements of sustainable development.

[0004] Waste asphalt concrete recycling technology can be divided into hot recycling and cold recycling, which can be divided into: ① In-situ cold recycling technology; ② Plant-mixed cold recycling technology; ③ In-situ hot recycling technology; ④ Plant-mixed hot recycling technology; ⑤ Full-depth recycling technology. Among them, plant-mixed hot recycling technology is being adopted and promoted by more and more projects because it can make the most of waste asphalt concrete materials and can produce high-quality recycled asphalt materials that can meet the requirements of pavement construction. The key to factory-mixed hot-recycled asphalt and asphalt concrete technology is to add a certain amount of regeneration agent. The main function of the regeneration agent is to adjust the composition of asphalt. By adding the regeneration agent, the rheological index of asphalt can be improved and its viscosity can be reduced, so that the performance of aged asphalt can be restored and it can be well bonded with new asphalt, new aggregate and old materials to achieve the purpose of regeneration. The use of regeneration agent will increase material costs, and the regeneration agent needs to be dispersed and mixed for a long time when regenerating waste asphalt, making the process complicated and time-consuming. The use of regeneration agent will also affect the high-temperature stability and ductility of recycled asphalt to a certain extent. In addition, it is generally believed in the industry that when the proportion of old asphalt exceeds 15%, a special regeneration agent must be used for asphalt regeneration. Therefore, the current interest rate for waste asphalt materials in asphalt road construction is generally not high. At the same time, when using the regeneration agent, it is necessary to accurately determine the addition ratio of the old asphalt mixture and the regeneration agent, which has high requirements for the process.

[0005] CN111304991A discloses a factory-mixed hot regeneration maintenance method for drainage asphalt pavement, which mixes old materials, regeneration agent, new aggregate, new asphalt, mineral powder and fiber to obtain factory-mixed hot regeneration drainage asphalt mixture, wherein the factory-mixed hot regeneration drainage asphalt mixture includes: 10-50% of the old materials, 3-4% of the mineral powder, 0.1-0.3% of the fiber, and the total amount of asphalt contained in the old materials and the new asphalt is 4-5%. The high-quality coarse aggregate and high-viscosity asphalt material of the old drainage asphalt pavement are effectively utilized, and the regeneration agent, new aggregate and new asphalt are reasonably mixed. By optimizing the mix ratio design and construction process, the performance indicators of the regenerated mixture and the regenerated drainage asphalt pavement can meet the technical requirements of the newly built drainage asphalt pavement. However, the method adds a regeneration agent, which increases the cost and the process is complicated.

[0006] CN112174576A discloses a factory-mixed hot-regenerated asphalt mixture and a processing method thereof, comprising the following components: by weight, 60-70 parts of recycled old materials, 1-3 parts of new asphalt, 20-30 parts of new aggregate, 4-6 parts of mineral powder and 1-4 parts of modified components; wherein the modified components include the following components by weight: 20-30 parts of polyethylene glycol, 1-3 parts of reinforcing fiber, 8-10 parts of anti-stripping agent, 60-70 parts of solubilizer, 5-8 parts of warm mix agent and 10-15 parts of regeneration agent. The hot-regenerated asphalt mixture has a high dosage and high regeneration efficiency; the hot-regenerated asphalt mixture has a uniform texture, stable performance and meets the performance requirements of hot-mix asphalt mixture, but a large amount of regeneration agent is also used, and the new and old asphalt of the product cannot achieve good dispersion and compounding.

[0007] CN113668328A discloses a method for realizing high-quality recycling of RAP with large dosage, optimizing the pretreatment process of RAP, firstly screening RAP, then crushing and grading the RAP on the screen, until the treated RAP meets the requirements of large dosage and controllable use, significantly improving the efficiency and quality of standardized treatment. However, this method is also relatively complicated and cumbersome, and cannot be applied in industry.

[0008] CN115925324A discloses a high-dosage RAP plant-mixed AC-25 hot-regenerated asphalt mixture and its preparation method. The RAP particle size variation trend obtained by the combustion method is used to obtain the qualified gradation by the trial mixing method to increase the RAP dosage to 30%-40%. On the basis of ensuring the performance of the finished hot-regenerated mixture, RAP is used in a high dosage. The amount of new asphalt is saved by regenerating the old asphalt, and the amount of asphalt is reduced by adding the waste oil regeneration agent, which greatly saves production costs and produces obvious economic benefits. This method is also relatively cumbersome and uses a regeneration agent.

[0009] Through the recycling technology, discarded asphalt mixture can be recycled, which reduces the mining of new materials and the consumption of non-renewable resources such as sand and asphalt, reduces the cost of pavement, and saves asphalt. The use of recycled asphalt mixture has good economic, social and environmental benefits. However, in actual production, factory-mixed hot recycled asphalt mixture still has the problems of low RAP utilization rate, complicated process or the need to use regeneration agent. Therefore, on the basis of meeting the relevant asphalt mixture performance, how to increase the RAP incorporation in asphalt concrete and not use regeneration agent to improve the utilization rate of recycled asphalt mixture is an urgent problem to be solved in the industry. Summary of the invention

[0010] In view of the limitations of the above-mentioned prior art, the present invention provides a method for recycling waste pavement asphalt. The method for recycling waste pavement asphalt of the present invention is simple and easy to implement, does not require a regeneration agent, and the proportion of waste pavement asphalt in the regenerated asphalt concrete is high, and the regenerated asphalt concrete meets the requirements of pavement construction.

[0011] A method for recycling waste road asphalt, wherein the raw materials of the recycling method include m parts by weight of road asphalt milling material, n parts by weight of new asphalt, t parts by weight of new aggregate, and s parts by weight of fiber, wherein the particle size of the new aggregate is greater than 5 mm;

[0012] The recycling method comprises the following steps:

[0013] Step 1, crushing the road surface asphalt milling material: the particle size of the road surface asphalt milling material after crushing is less than 5mm;

[0014] Step 2, road asphalt milling material testing: randomly select p parts by weight of crushed road asphalt milling material, wash and dry it with tri-filter ethylene to obtain q parts by weight of fine aggregate;

[0015] Step 3, preparation of recycled asphalt concrete: place m parts by weight of crushed road asphalt milling material in a stirring pot for heating, add 0.2n-0.3n parts by weight of new asphalt and stir evenly, wherein the heating temperature is 100-120°C; continue to add t parts by weight of new aggregate and s parts by weight of fiber to the stirring pot, while raising the temperature of the stirring pot to 130-150°C, and stir the mixture evenly; continue to add 0.45n-0.55n parts by weight of new asphalt to the stirring pot, raise the temperature of the stirring pot to 160-170°C, and stir the mixture evenly; finally, add the remaining amount of new asphalt and stir evenly to obtain recycled asphalt concrete;

[0016] In step 1, the pavement asphalt milling material is crushed into smaller particles, so that the coarse aggregate in the pavement asphalt milling material can expose more of the surface without asphalt inside, and then in step 3, 20% by weight of new asphalt is initially added, and at a temperature of 100-120° C., the new asphalt mixes and evenly wraps the broken pavement asphalt milling material, and then large particles of new aggregate and fiber are added, and the temperature is increased to 130-150° C. The fiber can adhere to the surface of the broken pavement asphalt milling material wrapped with the new asphalt, and at the same time, the broken pavement asphalt milling material wrapped with the new asphalt and fiber is evenly mixed with the large particles of new aggregate by stirring, and then 50% by weight of new asphalt is added respectively, and the mixture is mixed and stirred evenly, and then the remaining 30% of new asphalt is added.

[0017] In the entire preparation process, there is no need to use solvents to wash the pavement asphalt milling material to remove the influence of old asphalt on the regeneration of old aggregates, nor is there a need to add a regeneration agent, which saves costs. At the same time, the present invention ingeniously crushes the surface pavement asphalt milling material to obtain a large number of new cut surfaces that are not adhered to old asphalt. The contact and bonding strength of the new cut surfaces with the new asphalt are similar to those of new aggregates. Therefore, a small portion of new asphalt is first mixed evenly with the crushed pavement asphalt milling material, so that the new asphalt can be evenly attached to the surface of the pavement asphalt milling material, and then mixed with large particles of new aggregate and fiber. The mixing of large and small particles can reduce the gaps between aggregates and is easier to mix evenly. The addition of fiber is also very beneficial to the strength improvement of recycled asphalt concrete. In actual experiments and construction, it is found that adding new asphalt to the mixture in batches according to a certain proportion is more conducive to the coating of aggregates and RAP than adding it to the mixture in a conventional concentrated manner, and the obtained asphalt concrete has a longer service stability.

[0018] Wherein, m, n, t, s, p, q are all greater than 0, and m<t, and the weight parts of each raw material satisfy the relationship (I)-(III):

[0019]

[0020]

[0021] 2m(1-q)3p≤s≤n(Ⅲ);

[0022] As a preferred solution, the inventors observed different asphalt milling materials on the road surface and found that the amount of new asphalt added depends on the content of the original asphalt on the one hand, and is also related to the total weight of the newly added components on the other hand. It is speculated that this is due to the appearance of new cross-sections of old aggregates, which can largely avoid the impact of old asphalt on recycling and reuse; and adding new asphalt in batches is, on the one hand, to ensure more complete contact with the recycled old materials, and on the other hand, to ensure more uniform mixing, so as to obtain more uniform recycled asphalt concrete.

[0023] As a preferred solution, the specific operation steps of milling and removing the asphalt from the broken road surface in step 1 are:

[0024] Step 1.1, initial crushing: firstly, the road asphalt milling material is initially crushed to obtain crushed material 1;

[0025] Step 1.2, initial screening: screening the crushed material 1 through a 5-mesh sieve to separate the pavement asphalt milling material with a particle size of less than 5 mm from other large-particle pavement asphalt milling material in the crushed material 1;

[0026] Step 1.3, secondary crushing: crushing other large-particle road asphalt milling materials to obtain crushed material 2;

[0027] Step 1.4, multiple screening and crushing: Repeat steps 1.2-1.3 until all the road asphalt milling materials can pass through the 5-mesh sieve.

[0028] As a preferred solution, the equipment used in the comminution method is one or more of an impact crusher, a jaw crusher, a cone crusher, a mobile crusher or a hammer crusher.

[0029] As a preferred solution, the fiber is one or more of rubber fiber, glass fiber, and plant fiber;

[0030] As a preferred solution, the fibers are preferably glass fibers.

[0031] Compared with the prior art, the present invention has the following advantages and outstanding effects:

[0032] It can achieve the use of large amounts of recycled materials in asphalt pavement, and no regeneration agent is used in the raw materials, which effectively realizes the reuse of asphalt waste and reduces the cost of road maintenance or paving, with high economic and environmental benefits; the preparation process is simple, without the need for complex procedures, and simply controlling asphalt preparation parameters such as temperature can effectively improve the performance of recycled asphalt materials and meet the requirements of pavement construction; when using fiber additives, the mechanical strength and crack resistance of the product are improved. At the same time, combined with a specific production process, the addition of fibers also improves the low-temperature stability of recycled asphalt concrete to a certain extent, effectively reducing the occurrence of low-temperature cracking.

[0033] The asphalt pavement thermal regeneration technology in the present invention directly uses the collected asphalt waste from old pavement. By crushing and screening the waste asphalt materials, the particle size of the asphalt waste during mixing is effectively controlled. Combined with the gradual addition of new asphalt, the adhesion and coating performance of asphalt and aggregate in the asphalt concrete product and the asphalt waste are effectively improved, and a more uniform recycled asphalt concrete can be obtained. The large amount of asphalt waste generated in the current road maintenance can be directly utilized, saving a large amount of asphalt and sand and gravel materials; in addition, it can also effectively solve the secondary pollution of the asphalt concrete waste to the disposal site environment, which can not only effectively protect the forest land, but also maintain the natural landscape and ecological environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the process steps of the method for recycling waste pavement asphalt in Example 1. DETAILED DESCRIPTION

[0035] The present invention is described in detail below in conjunction with specific drawings and embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the content of the present invention still fall within the scope of protection of the present invention.

[0036] Example 1

[0037] Prepare pavement asphalt milling material m=1000 weight parts, new asphalt n=125 weight parts, new aggregate t=1300 weight parts, glass fiber s=75 weight parts, wherein the particle size of the new aggregate is greater than 5 mm, and the crushed pavement asphalt milling material p=10 weight parts is used in step 2. The specific recycling method includes the following steps:

[0038] Step 1, crushing the road surface asphalt milling material: the particle size of the road surface asphalt milling material after crushing is less than 5mm;

[0039] Step 1.1, primary crushing: firstly, the road asphalt milling material is crushed by an impact crusher to obtain crushed material 1;

[0040] Step 1.2, initial screening: screening the crushed material 1 through a 5-mesh sieve to separate the pavement asphalt milling material with a particle size of less than 5 mm from other large-particle pavement asphalt milling material in the crushed material 1;

[0041] Step 1.3, secondary crushing: crushing other large-particle road asphalt milling materials with an impact crusher to obtain crushed material II;

[0042] Step 1.4, multiple screening and crushing: Repeat steps 1.2-1.3 until all the road asphalt milling materials can pass through the 5-mesh sieve.

[0043] Step 2, road asphalt milling material testing: randomly select p = 10 parts by weight of crushed road asphalt milling material, wash and dry it with tri-filter ethylene to obtain fine aggregate q = 9.4 parts by weight;

[0044] Step 3, preparation of recycled asphalt concrete: place m = 1000 parts by weight of crushed road asphalt milling material in a stirring pot and heat it, add 0.25n = 31.25 parts by weight of new asphalt and stir evenly, wherein the heating temperature is 100-120°C; continue to add t = 1300 parts by weight of new aggregate and s = 75 parts by weight of glass fiber into the stirring pot, while raising the temperature of the stirring pot to 130-150°C, and stirring the mixture evenly; continue to add 0.5n = 62.5 parts by weight of new asphalt into the stirring pot, raise the temperature of the stirring pot to 160-170°C, and stir the mixture evenly; finally, add the remaining 0.25n = 31.25 parts by weight of new asphalt and stir evenly to obtain recycled asphalt concrete.

[0045] Embodiment 2-5

[0046] In step 3 of Example 2-5, the weight portions of new asphalt added three times are different, see Table 1 for details, and other parameters and processes are the same as in Example 1.

[0047] Table 1 Weight parts of new asphalt added three times in step 3 of Example 2-5

[0048] First weight portion Second weight portion The third weight portion Example 2 0.2n＝25 0.55n＝68.75 0.25n＝31.25 Example 3 0.3n＝37.5 0.45n＝56.25 0.25n＝31.25 Example 4 0.25n＝31.25 0.55n＝68.75 0.2n＝25 Example 5 0.25n＝31.25 0.45n＝56.25 0.3n＝37.5

[0049] Example 6

[0050] In Example 6, except that n=120 and s=80, other parameters and processes are the same as in Example 1, that is, the three addition ratios of new asphalt in step 3 are still 0.25n, 0.5n and 0.25n.

[0051] Example 7

[0052] In Example 7, except that n=130 and s=70, other parameters and processes are the same as in Example 1, that is, the three addition ratios of new asphalt in step 3 are still 0.25n, 0.5n and 0.25n.

[0053] Example 8

[0054] In Example 8, except that n=144 and s=56, other parameters and processes are the same as in Example 1, that is, the three addition ratios of new asphalt in step 3 are still 0.25n, 0.5n and 0.25n.

[0055] Example 9

[0056] In Example 9, except t=1250, other parameters and processes are the same as those in Example 1.

[0057] Example 10

[0058] In Example 10, except t=1570, other parameters and processes are the same as those in Example 1.

[0059] Comparative Example 1

[0060] Comparative Example 1 does not include step 1, and other parameters and processes are the same as those of Example 1.

[0061] Comparative Example 2

[0062] In step 3 of comparative example 2, the milled asphalt material of the crushed road surface is directly mixed with all the new asphalt, glass fiber and new aggregate, and heated to 160-170° C. and stirred evenly to obtain recycled asphalt concrete; other parameters and processes are the same as those in example 1.

[0063] Comparative Example 3

[0064] In step 3 of comparative example 3, no glass fiber was added; other parameters and processes were the same as those of example 1.

[0065] Comparative Examples 4-7

[0066] In step 3 of comparative examples 4-7, the weight portions of new asphalt added three times are different, see Table 2 for details, and other parameters and processes are the same as those of Example 1.

[0067] Table 2 Weight parts of new asphalt added three times in step 3 of comparative examples 4-7

[0068]

[0069]

[0070] Comparative Example 8

[0071] In Comparative Example 8, except that n=165 and s=35, other parameters and processes are the same as those in Example 1, that is, the three addition ratios of new asphalt in step 3 are still 0.25n, 0.5n and 0.25n.

[0072] Comparative Example 9

[0073] In Comparative Example 9, except that n=90 and s=110, other parameters and processes are the same as those in Example 1, that is, the three addition ratios of new asphalt in Step 3 are still 0.25n, 0.5n and 0.25n.

[0074] Comparative Example 10

[0075] In Comparative Example 10, except t=1100, other parameters and processes are the same as those in Example 1.

[0076] Comparative Example 11

[0077] In Comparative Example 11, except t=1600, other parameters and processes are the same as those in Example 1.

[0078] The prepared recycled asphalt concrete was subjected to Marshall test, -10℃ low temperature splitting test and 60℃ rutting test, and the relevant experimental data were obtained and shown in Table 3.

[0079] Table 3 Performance parameters of recycled asphalt concrete obtained in the examples and comparative examples

[0080]

[0081]

[0082] It can be seen from the data in Table 3 that the performance parameters of the Marshall test of the product of the scheme of the present invention all meet the requirements of the road construction standard. In the embodiments of the present invention, a relatively high RAP addition amount is adopted and the waste asphalt material is not treated with a regeneration agent. It can be seen that the scheme of the present invention can realize the large-scale reuse of waste road asphalt materials and has good economic and environmental value.

[0083] By comparing Example 1 with Comparative Example 1, it can be seen that since the comparative example does not carry out multiple crushing and screening in step 1 and crush the pavement asphalt milling material to a particle size of less than 5 mm, even if new asphalt is added in steps, the pavement asphalt milling material does not have many fresh cut surfaces and cannot be excessively wrapped by new asphalt, which makes the low-temperature stability of the asphalt material worse and the tensile strength relatively low, which can easily lead to cracking and damage of the asphalt pavement at low temperatures.

[0084] From the comparison of comparative example 3, it can be seen that the addition of a small amount of fiber can effectively improve the low-temperature degradation caused by the introduction of waste asphalt recycled materials into asphalt concrete materials. The addition of fiber materials can be dispersed inside the asphalt concrete, play a certain connecting role between aggregate particles, and improve the overall stability of the material. From comparative examples 4-7, it can be seen that the use of the specific new asphalt introduction method of the present application can effectively promote the adhesion and dispersion between asphalt materials and RAP and aggregates, and improve the high-temperature and low-temperature performance of asphalt concrete materials as a whole. In comparative example 2, since step 3 is not mixed in steps and heated in a gradient, although the road asphalt milling material is broken, it is not well wrapped by the new asphalt, and the new asphalt excessively wraps the large particles of new aggregate, which ultimately leads to poor uniformity and wrapping of the recycled asphalt concrete. The obtained asphalt concrete material has poor high-temperature performance and poor low-temperature crack resistance.

[0085] By comparing Examples 1-5 with Comparative Examples 4-7, it can be seen that in Examples 1-5, in process step 3, the three additions of new asphalt meet 0.2-0.3n and 0.45-0.55n respectively and the balance is added last, and the regenerated asphalt concrete has better performance, and the obtained asphalt concrete material has better overall performance and can meet the construction requirements; while in Comparative Examples 4-7, the three addition amounts are not strictly in accordance with the above range. When the first addition is too little (Comparative Examples 4 and Comparative Examples 6), the new asphalt cannot wrap the broken pavement asphalt milling material well, resulting in the pavement asphalt milling material not being fully utilized. Even if new asphalt is added later, it will be more wrapped on the large new aggregate, and the final regenerated asphalt concrete has poor strength due to poor uniformity; on the contrary, when too much is added for the first time (Comparative Examples 5 and Comparative Examples 7), the broken pavement asphalt milling material is better wrapped by the new asphalt, but after subsequent mixing with the large new aggregate, due to the lack of new asphalt in the last two times, the new aggregate wrapping is poor, and the final regenerated asphalt concrete has poor strength due to poor uniformity.

[0086] By comparing Example 1 with Examples 6-8 and Comparative Examples 8-9, it can be seen that when n and s of Comparative Example 1 and Examples 6-8 satisfy formula (III), recycled concrete with better performance is obtained. On the contrary, in Comparative Example 8-9, too little glass fiber and too much new asphalt will cause asphalt waste. At the same time, the strength is low due to the small amount of glass fiber, and too much glass fiber and too little new asphalt, and the poor wrapping property does not result in high-strength recycled asphalt concrete.

[0087] By comparing Example 1 with Examples 9-10 and Comparative Examples 10-11, it can be seen that when the new aggregate is too little (Comparative Example 10), the performance is poor. This is because too much asphalt is milled off from the road surface and the new asphalt cannot be blended with too much waste. When there is too much new aggregate (Comparative Example 11), although the performance is acceptable, the proportion of waste utilization is too small and the commercial value is low.

[0088] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for recycling waste road asphalt, wherein the raw materials of the recycling method include m parts by weight of road asphalt milling material, n parts by weight of new asphalt, t parts by weight of new aggregate, and s parts by weight of fiber, wherein the particle size of the new aggregate is greater than 5 mm; The recycling method comprises the following steps: Step 1, crushing the road surface asphalt milling material: the particle size of the road surface asphalt milling material after crushing is less than 5mm; Step 2, road asphalt milling material testing: randomly select p parts by weight of crushed road asphalt milling material, wash and dry it with tri-filter ethylene to obtain q parts by weight of fine aggregate; Step 3, preparation of recycled asphalt concrete: place m parts by weight of crushed road asphalt milling material in a stirring pot for heating, add 0.2n-0.3n parts by weight of new asphalt and stir evenly, wherein the heating temperature is 100-120°C; continue to add t parts by weight of new aggregate and s parts by weight of fiber to the stirring pot, while raising the temperature of the stirring pot to 130-150°C, and stir the mixture evenly; continue to add 0.45n-0.55n parts by weight of new asphalt to the stirring pot, raise the temperature of the stirring pot to 160-170°C, and stir the mixture evenly; finally, add the remaining amount of new asphalt and stir evenly to obtain recycled asphalt concrete; Wherein, m, n, t, s, p, q are all greater than 0, and m<t, and the weight parts of each raw material satisfy the relationship (I)-(III): 2m(1-q) / 3p≤s≤n (III); The fiber is one or more of rubber fiber, glass fiber and plant fiber.

2. The method for recycling waste road asphalt according to claim 1, characterized in that: The specific operation steps of milling and removing the asphalt from the broken road surface in step 1 are as follows: Step 1.1, initial crushing: firstly, the road asphalt milling material is initially crushed to obtain crushed material 1; Step 1.2, initial screening: screening the crushed material 1 through a 5-mesh sieve to separate the pavement asphalt milling material with a particle size of less than 5 mm from other large-particle pavement asphalt milling material in the crushed material 1; Step 1.3, secondary crushing: crushing other large-particle road asphalt milling materials to obtain crushed material 2; Step 1.4, multiple screening and crushing: Repeat steps 1.2-1.3 until all the road asphalt milling materials can pass through the 5-mesh sieve.

3. The method for recycling waste road asphalt according to claim 2, characterized in that: The equipment used in the comminution method is one or more of an impact crusher, a jaw crusher, a cone crusher, a mobile crusher or a hammer crusher.

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