A warm mix foamed recycled asphalt production equipment and process

Abstract

The present application discloses a warm-mix foamed regenerated asphalt production device and process, which relates to the field of pavement asphalt technology. A warm-mix foamed regenerated asphalt production device includes a flexible separator, a first countercurrent roller, a second countercurrent roller, a foaming machine, a solution storage tank, a stabilizer storage tank, a mixing tank, and a coupling agent storage tank. The two ends of the flexible separator are respectively connected to the first countercurrent roller and the second countercurrent roller. The first countercurrent roller is connected to the foaming machine through a pipeline. The second countercurrent roller is connected to the mixing tank through a pipeline. The solution storage tank is connected to the upper side of the foaming machine through a pipeline. The stabilizer storage tank is connected to the lower side of the foaming machine through a pipeline. The outlet end of the foaming machine is connected to the mixing tank through a pipeline. The coupling agent storage tank is connected to the mixing tank pipeline. The production equipment and process of the present application improve the reuse rate of old asphalt recycled materials, can also achieve asphalt mixing at a lower temperature, improve the warm-mix foaming effect, and reduce the foam burst rate.

Description

Technical Field

[0001] The present application relates to the technical field of pavement asphalt, and in particular to a warm mix foamed recycled asphalt production device and process. Background Art

[0002] Asphalt pavement recycling technology is a primary means of achieving the recycling of pavement materials. Depending on the specific needs of recycled asphalt and the requirements of road renovation, recycled asphalt can be partially or entirely used. By adding specific asphalt or additives, the resulting mixture can achieve the same quality as newly mixed asphalt, avoiding duplication of investment and saving costs. Foamed asphalt is produced by adding a small amount of water to hot asphalt, which creates fine foam and causes the asphalt to expand. This temporarily changes the asphalt's physical properties and significantly reduces its viscosity, allowing it to be easily mixed evenly with cold, wet aggregate without the additional emulsification process required for emulsified asphalt or the high-temperature heating required for hot mix, which consumes a lot of energy.

[0003] Traditional hot recycling technology for recycled asphalt suffers from issues such as high processing temperatures, which can cause the asphalt to age and clump easily. This also limits the reuse of recycled asphalt. Furthermore, during warm-mix foaming, the foam easily collapses, affecting the effectiveness of the warm-mix foaming process. Therefore, a warm-mix foamed recycled asphalt production equipment and process are proposed. Summary of the Invention

[0004] The main purpose of this application is to provide a warm mix foamed recycled asphalt production equipment and process, aiming to solve the technical problems in the existing technology of low utilization rate of old asphalt recycled materials and poor foaming effect.

[0005] To achieve the above-mentioned purpose, the present application proposes a warm-mix foamed recycled asphalt production equipment, including a flexible separator, a first countercurrent roller, a second countercurrent roller, a foaming machine, a solution storage tank, a stabilizer storage tank, a mixing tank and a coupling agent storage tank. The two ends of the above-mentioned flexible separator are respectively connected to the above-mentioned first countercurrent roller and the above-mentioned second countercurrent roller, the above-mentioned first countercurrent roller is connected to the above-mentioned foaming machine through a pipeline, the above-mentioned second countercurrent roller is connected to the above-mentioned mixing tank through a pipeline, the above-mentioned solution storage tank is connected to the upper side of the above-mentioned foaming machine through a pipeline, the above-mentioned stabilizer storage tank is connected to the lower side of the above-mentioned foaming machine through a pipeline, the outlet end of the above-mentioned foaming machine is connected to the above-mentioned mixing tank through a pipeline, and the above-mentioned coupling agent storage tank is connected to the above-mentioned mixing tank pipeline.

[0006] Optionally, a bag dust collector is also included, which is respectively connected to the exhaust gas outlet end of the first countercurrent drum and the exhaust gas outlet end of the second countercurrent drum, and the exhaust gas end of the bag dust collector is connected to the processor, and the processor is connected to the waste liquid pool.

[0007] Optionally, the outlet end of the bag filter is connected to a powder tank, the powder tank is connected to the mixing tank via a pipeline, and a fifth flow meter is provided between the powder tank and the mixing tank.

[0008] Optionally, a vibrating screen and a coarse material storage tank are connected to the second countercurrent drum and the mixing tank in sequence through pipelines, and a second flow meter is provided between the coarse material storage tank and the mixing tank.

[0009] Optionally, a solution pump is connected to the lower side of the solution storage tank, and the other end of the solution pump is connected to a first two-position three-way valve. One path of the first two-position three-way valve is connected to the upper side of the solution storage tank, and the other path of the first two-position three-way valve is connected to a third flow meter. A one-way valve is provided between the third flow meter and the foaming machine.

[0010] Optionally, a stabilizer pump is connected to the lower side of the stabilizer storage tank, and the other end of the stabilizer pump is connected to a second two-position three-way valve. One path of the second two-position three-way valve is connected to the upper side of the stabilizer storage tank, and the other path of the second two-position three-way valve is connected to a fourth flow meter. A control valve is provided between the fourth flow meter and the foaming machine.

[0011] This application also proposes a warm mix foamed regenerated asphalt production process, based on the aforementioned warm mix foamed regenerated asphalt production equipment, comprising the following steps:

[0012] After the old asphalt recycling material is crushed and screened by a flexible separator, coarse material with a particle size greater than 3mm and fine material with a particle size less than 3mm are obtained respectively;

[0013] The coarse material is subjected to an asphalt stripping operation to strip and collect the old asphalt on the surface of the aggregate of the coarse material to obtain the old asphalt; the coarse material after the asphalt stripping is heated to 110-120°C by a second countercurrent drum, and then screened by a vibrating screen to obtain the recycled hot material;

[0014] The old asphalt and the fine material are mixed and put into the first countercurrent drum and heated to 160-170°C. Then, the old asphalt and the fine material are put into the foaming machine. At the same time, the H2CO3 solution in the solution storage tank and the stabilizer in the stabilizer storage tank are added into the foaming machine for foaming and stirring by the stirring roller in the foaming machine. After the foaming is completed, foamed asphalt is obtained.

[0015] The tail gas generated when the coarse material and the fine material are heated is treated by a bag dust collector to obtain a recovered powder;

[0016] The above-mentioned regenerated hot material, the above-mentioned foamed asphalt and the above-mentioned recycled powder are mixed in a mixing tank, and the coupling agent in the coupling agent storage tank is added into the mixing tank for stirring to obtain warm-mixed foamed regenerated asphalt.

[0017] Optionally, the step of treating the exhaust gas generated when the above-mentioned coarse material and the above-mentioned fine material are heated by a bag dust collector includes: recovering the exhaust gas generated when the above-mentioned coarse material and the above-mentioned fine material are heated by a bag dust collector and removing dust to obtain recovered powder and waste gas, desulfurizing the above-mentioned waste gas in a processor, and storing it in a waste liquid pool after treatment.

[0018] Optionally, the stabilizer includes aluminum silicate mineral, montan wax, sodium α-olefin sulfonate and calcium stearate.

[0019] Optionally, the coupling agent is 3-aminopropyltriethoxysilane.

[0020] The production equipment of the present application first crushes and screens the old asphalt recycling material through a flexible separator, and then heats the fine material through the first countercurrent drum, while the coarse material enters the second countercurrent drum through a pipeline for heating. The tail gas generated during the heating of the coarse and fine materials is recovered and processed through a bag dust collector, and the obtained powder enters the mixing tank. The unusable waste gas enters the processor through a pipeline for desulfurization treatment and then humidified and discharged into the waste liquid pool. The coarse material enters the mixing tank after countercurrent heating, and the fine material enters the foaming machine after countercurrent heating. At the same time, the solution storage tank injects H2CO3 solution from the upper side of the foaming machine to stabilize the The stabilizer is injected from the bottom of the foaming machine into the agent storage tank to foam the asphalt. The H2CO3 solution enters from the top of the foaming machine, and the stabilizer enters from the bottom of the foaming machine. H2CO3 is easily decomposed when it encounters hot fine materials, and the stabilizer enters from the bottom of the foaming machine when the asphalt has begun to foam, which avoids the stabilizer staying only on the surface of the asphalt foam and reduces the foam bursting rate. The obtained foamed asphalt is then injected into the mixing tank, and the coupling agent is added to the mixing tank from the coupling agent storage tank. The coupling agent can enhance the adhesion between the foamed asphalt and the aggregate. After stirring together, warm-mix foamed recycled asphalt is prepared. The production equipment of the present application adopts a countercurrent thermal regeneration method to heat the coarse material and the fine material separately, and recovers and processes the exhaust gas generated by the heating, and collects the powder, thereby realizing the full regeneration of the old asphalt recycled material and improving the reuse rate of the old asphalt recycled material. And because the coarse material is easy to age, its heating temperature is lowered, while the fine material is easy to foam at high temperature and prepared into foamed asphalt. At this time, the viscosity of the foamed asphalt is reduced, and the asphalt can be warm mixed at a lower temperature, thereby realizing the temperature control of the old asphalt recycling material, and performing countercurrent thermal regeneration separately, not only can control the aging degree of asphalt, but also can solve to a certain extent the problems of uneven heating of materials, easy agglomeration, and low proportion of old asphalt recycling materials added in the downstream regeneration technology. The foamed asphalt warm mixing technology can save energy consumption and reduce emissions.

[0021] In addition, in the production process of the present application, the old asphalt recycling material is first crushed and screened to separate the coarse material with a particle size greater than 3 mm and the fine material with a particle size less than 3 mm. The coarse material can be stripped of asphalt to obtain the old asphalt. After the old asphalt is mixed with the fine material, the asphalt content in the fine material can be made higher, reaching 80%, ensuring the foaming effect, and the asphalt content in the coarse material is low, and can be used as aggregate later; since the heating temperature of the coarse material should not be too high, it is controlled at 110-120°C, and the fine material is easy to foam at high temperature, so the heating temperature is controlled at 160-170°C, and then H2CO3 solution and stabilizer are added for foaming. H2CO3 is easily decomposed by heat, and will produce CO2 and water, and CO2 can be used as foaming The gas enters the interior of the foamed asphalt, and then the foam shape is stabilized with a stabilizer to prevent the foam from bursting, thereby preparing foamed asphalt with better foaming performance. During the countercurrent heating process of coarse and fine materials, the tail gas generated is recovered and treated. Not only can the recovered powder be reused, but the unusable waste gas is also desulfurized to avoid environmental pollution. Finally, the recycled hot material, foamed asphalt and recycled powder are mixed, and a coupling agent is added. The coupling agent can enhance the adhesion between the foamed asphalt and the aggregate. This production process not only realizes the full regeneration of old asphalt recycled materials and improves the reuse rate of old asphalt recycled materials, but also can achieve asphalt mixing at a lower temperature, and can also improve the warm mixing foaming effect and reduce the foam bursting rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0023] Figure 1 This is a schematic structural diagram of the warm mix foamed regenerated asphalt production equipment described in an embodiment of the present application;

[0024] Figure 2 This is a schematic diagram of the material flow inside the first countercurrent drum in an embodiment of the present application.

[0025] Reference numerals:

[0026] 1-flexible separator; 2-first countercurrent drum; 21-first flowmeter; 3-second countercurrent drum; 31-vibrating screen; 32-coarse material storage tank; 33-second flowmeter; 4-foaming machine; 5-solution storage tank; 51-solution pump; 52-first two-position three-way valve; 53-third flowmeter; 54-one-way valve; 6-stabilizer storage tank; 61-stabilizer pump; 62-second two-position three-way valve; 63-fourth flowmeter; 64-control valve; 7-mixing tank; 8-bag collector; 81-processor; 82-waste liquid tank; 83-powder tank; 84-fifth flowmeter; 9-coupling agent storage tank; 91-conveyor.

[0027] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0029] The current hot regeneration technology of old asphalt recycling materials has the problem of aging and easy agglomeration of old asphalt due to the high processing temperature. The reuse rate of old asphalt recycling materials is not high, and the foam is easy to burst when the asphalt is warm-mixed and foamed, which affects the warm-mixing and foaming effect.

[0030] In order to solve the above technical problems, an embodiment of the present application provides a warm-mix foamed recycled asphalt production equipment, including a flexible separator 1, a first countercurrent roller 2, a second countercurrent roller 3, a foaming machine 4, a solution storage tank 5, a stabilizer storage tank 6, a mixing tank 7 and a coupling agent storage tank 9. The two ends of the above-mentioned flexible separator 1 are respectively connected to the above-mentioned first countercurrent roller 2 and the above-mentioned second countercurrent roller 3, the above-mentioned first countercurrent roller 2 is connected to the above-mentioned foaming machine 4 through a pipeline, the above-mentioned second countercurrent roller 3 is connected to the above-mentioned mixing tank 7 through a pipeline, the above-mentioned solution storage tank 5 is connected to the upper side of the above-mentioned foaming machine 4 through a pipeline, the above-mentioned stabilizer storage tank 6 is connected to the lower side of the above-mentioned foaming machine 4 through a pipeline, the outlet end of the above-mentioned foaming machine 4 is connected to the above-mentioned mixing tank 7 through a pipeline, and the above-mentioned coupling agent storage tank 9 is connected to the above-mentioned mixing tank 7 through a pipeline.

[0031] like Figure 1 As shown, in this application, the old asphalt recycling material is first crushed and screened by the flexible separator 1, and the first countercurrent drum 2 heats the fine material (such as Figure 2As shown), the coarse material enters the second countercurrent drum 3 through the pipeline for heating. After countercurrent heating, the coarse material enters the mixing tank 7, and the fine material enters the foaming machine 4 after countercurrent heating. At the same time, the solution storage tank 5 injects the solution from the upper side of the foaming machine 4, and the stabilizer storage tank 6 injects the stabilizer from the lower side of the foaming machine 4 to foam the asphalt. The stabilizer enters from the lower side of the foaming machine 4 when the asphalt has started to foam, avoiding the stabilizer staying only on the surface of the asphalt foam and reducing the foam bursting rate. The obtained foamed asphalt is then injected into the mixing tank 7, and the coupling agent is added to the mixing tank 7 from the coupling agent storage tank 9. The coupling agent can enhance the adhesion between the foamed asphalt and the aggregate. After stirring together, warm-mix foamed regenerated asphalt is prepared. The production equipment of the present application adopts a countercurrent thermal regeneration method to heat the coarse material and the fine material separately, and recovers and processes the exhaust gas generated by the heating, and collects the powder, thereby realizing the full regeneration of the old asphalt recycling material and improving the reuse rate of the old asphalt recycling material. And because the content of old asphalt in the coarse material is low and it is easy to age, its heating temperature is lowered, and the fine material is easy to foam at high temperature and prepared into foamed asphalt. At this time, the viscosity of the foamed asphalt is reduced, and the asphalt can be warm mixed at a lower temperature, thereby realizing the temperature control of the old asphalt recycling material, and performing countercurrent thermal regeneration separately, not only can control the aging degree of asphalt, but also can solve to a certain extent the problems of uneven heating of materials, easy agglomeration, and low proportion of old asphalt recycling materials added in the downstream regeneration technology. The foamed asphalt warm mixing technology can save energy consumption and reduce emissions.

[0032] As an embodiment of the present application, a bag dust collector 8 is further included. The bag dust collector 8 is respectively connected to the exhaust gas outlet end of the first countercurrent drum 2 and the exhaust gas outlet end of the second countercurrent drum 3. The exhaust gas end of the bag dust collector 8 is connected to a processor 81, and the processor 81 is connected to a waste liquid tank 82. The exhaust gas generated during the heating of the coarse and fine materials can be recovered and processed by the bag dust collector 8. The unusable exhaust gas enters the processor 81 through a pipeline for desulfurization treatment and is then humidified and discharged into the waste liquid tank 82 to avoid environmental pollution.

[0033] As one possible embodiment of the present application, the outlet of the bag filter 8 is connected to a powder tank 83, which is connected to the mixing tank 7 via a pipeline. A fifth flowmeter 84 is provided between the powder tank 83 and the mixing tank 7. The powder removed by the bag filter 8 enters the mixing tank 7 and can be used as a filler for mixing with asphalt, further increasing the reuse rate of recycled asphalt.

[0034] As one possible embodiment of the present application, a vibrating screen 31 and a coarse material storage tank 32 are connected in sequence between the second countercurrent drum 3 and the mixing tank 7 via pipelines. A second flow meter 33 is provided between the coarse material storage tank 32 and the mixing tank 7. The coarse material heated by the second countercurrent drum 3 is further screened by the vibrating screen 31 and then stored in the coarse material storage tank 32. The coarse material is then metered by the second flow meter 33 before entering the mixing tank 7.

[0035] As one possible embodiment of the present application, a solution pump 51 is connected to the bottom of the solution storage tank 5. The other end of the solution pump 51 is connected to a first, two-position, three-way valve 52. One end of the first, two-position, three-way valve 52 is connected to the top of the solution storage tank 5. The other end of the first, two-position, three-way valve 52 is connected to a third flowmeter 53. A one-way valve 54 is provided between the third flowmeter 53 and the foaming machine 4. The solution stored in the solution storage tank 5 is pumped out by the solution pump 51, passes through the first, two-position, three-way valve 52, the third flowmeter 53, and the one-way valve 54 in sequence, and then enters the foaming machine 4. The first, two-position, three-way valve 52 is connected to the top of the solution storage tank 5 on one end and to the third flowmeter 53 on the other end. When in operation, the first, two-position, three-way valve 52 is reversed, allowing the solution and the fine material to enter the foaming machine 4 simultaneously. When not in operation, the solution storage tank 5 can be circulated through the first, two-position, three-way valve 52 to ensure uniform mixing of the solutions in the solution storage tank 5.

[0036] As one possible embodiment of the present application, the stabilizer storage tank 6 is connected to a stabilizer pump 61 at its lower side, and a second, two-position, three-way valve 62 at its other end. One end of the second, two-position, three-way valve 62 communicates with the upper side of the stabilizer storage tank 6, and the other end of the second, two-position, three-way valve 62 communicates with a fourth flowmeter 63. A control valve 64 is provided between the fourth flowmeter 63 and the foaming machine 4. The stabilizer stored in the stabilizer storage tank 6 is pumped out by the stabilizer pump 61, passes through the second, two-position, three-way valve 62, the fourth flowmeter 63, and the control valve 64, and then enters the foaming machine 4. The second, two-position, three-way valve 62 communicates with the upper side of the stabilizer storage tank 6 on one end and with the fourth flowmeter 63 on the other end. When in operation, the second, two-position, three-way valve 62 is switched to allow the stabilizer to enter the foaming machine 4. When not in operation, the stabilizer storage tank 6 can be circulated through the second, two-position, three-way valve 62 to ensure uniform mixing of the stabilizer in the stabilizer storage tank 6.

[0037] The embodiments of the present application further provide a warm mix foamed regenerated asphalt production process, which is based on the warm mix foamed regenerated asphalt production equipment of the aforementioned embodiments and specifically includes the following steps:

[0038] After the old asphalt recycling material is crushed and screened by the flexible separator 1, coarse material with a particle size greater than 3mm and fine material with a particle size less than 3mm are obtained respectively;

[0039] The coarse material is subjected to an asphalt stripping operation to strip and collect the old asphalt on the surface of the aggregate of the coarse material to obtain the old asphalt; the coarse material after the asphalt stripping is heated to 110-120°C by the second countercurrent drum 3, and then screened by the vibrating screen 31 to obtain the recycled hot material;

[0040] The old asphalt and the fine material are mixed and enter the first countercurrent drum 2 together and heated to 160-170°C. Then, they enter the foaming machine 4. At the same time, the H2CO3 solution in the solution storage tank 5 and the stabilizer in the stabilizer storage tank 6 are added to the foaming machine 4 for foaming and stirring by the stirring roller in the foaming machine. After the foaming is completed, foamed asphalt is obtained;

[0041] The tail gas generated when the coarse material and the fine material are heated is processed by the bag filter 8 to obtain a recovered powder;

[0042] The above-mentioned regenerated hot material, the above-mentioned foamed asphalt and the above-mentioned recycled powder are mixed in the mixing tank 7, and the coupling agent in the coupling agent storage tank 9 is added into the mixing tank 7 for stirring to obtain warm-mixed foamed regenerated asphalt.

[0043] The present application first crushes and screens the old asphalt recycling material to separate the coarse material with a particle size greater than 3mm and the fine material with a particle size less than 3mm. The coarse material can be stripped of asphalt to obtain the old asphalt. After the old asphalt is mixed with the fine material, the asphalt content in the fine material can be higher, reaching 80%, ensuring the foaming effect. The asphalt content in the coarse material is low and can be used as aggregate later. Since the heating temperature of the coarse material should not be too high, it is controlled at 110-120°C. The fine material is easy to foam at high temperature, so the heating temperature is controlled at 160-170°C, and then H2CO3 solution and stabilizer are added for foaming. H2CO3 is easily decomposed by heat, producing CO2 and water. CO2 can enter the interior of the foamed asphalt as a foaming gas, and then a stabilizer is used to stabilize the foam form to prevent the foam from bursting, thereby preparing foamed asphalt with good foaming performance. Finally, the recycled hot material, foamed asphalt and recycled powder are mixed, and a coupling agent is added. The coupling agent can enhance the adhesion between the foamed asphalt and the aggregate. This production process not only realizes the full regeneration of old asphalt recycled materials and improves the reuse rate of old asphalt recycled materials, but also can achieve warm mixing of asphalt at a lower temperature, and can also improve the warm mixing foaming effect and reduce the foam bursting rate.

[0044] As one possible implementation method of the present application, the step of treating the exhaust gas generated when the coarse and fine materials are heated by a bag dust collector includes: recovering the exhaust gas generated when the coarse and fine materials are heated by a bag dust collector and removing dust to obtain recovered powder and waste gas, desulfurizing the waste gas in a processor, and storing the recovered waste gas in a waste liquid tank after treatment. During the countercurrent heating process of the coarse and fine materials, the exhaust gas generated is recovered and treated, not only the recovered powder is reused, but also the unusable waste gas is desulfurized to avoid environmental pollution.

[0045] As one possible embodiment of the present application, the stabilizer includes aluminum silicate minerals, montan wax, sodium α-olefin sulfonate, and calcium stearate. Aluminum silicate minerals contain cavities and channels of uniform size, which absorb a large number of water molecules. During the asphalt foaming process, the aluminum silicate minerals will volatilize water vapor, which can cause the asphalt to expand faster and form foamed asphalt. Montan wax converts to a liquid state at around 115°C. After being added to the asphalt, it can improve the asphalt's softening properties and prevent the aluminum silicate minerals from causing the asphalt to foam rapidly due to excessive internal pressure and collapse. Sodium α-olefin sulfonate can entrain a large amount of air to form bubbles, further improving the foaming efficiency. However, because the bubbles are thin and unevenly distributed, calcium stearate is used to reduce the surface tension of the bubbles. Calcium stearate also has an air entraining effect, synergistically working with sodium α-olefin sulfonate to stabilize and evenly distribute the bubbles within the foamed asphalt, thereby preventing the foamed asphalt from collapsing during the molding process. Therefore, through the coordination of the stabilizer, the foaming effect of asphalt can be significantly improved and the breakage rate of foam can be reduced.

[0046] As one possible embodiment of the present application, the coupling agent is 3-aminopropyltriethoxysilane. The molecular structure of 3-aminopropyltriethoxysilane contains an active primary amino functional group and three easily hydrolyzed ethoxy groups. The ethoxy groups hydrolyze to form active silanol groups, which can undergo a condensation reaction with hydroxyl groups on the filler surface to form a chemical bond. The primary amino functional group of 3-aminopropyltriethoxysilane then chemically reacts with the asphalt. This two-way reaction improves the adhesion between the asphalt and the filler, compensating for the defect of foamed asphalt that suffers from reduced adhesion due to internal water content and is therefore prone to flaking.

[0047] The above technical solutions of the present application are described in detail below with reference to specific embodiments.

[0048] Example 1

[0049] A warm mix foamed recycled asphalt is prepared by the following steps:

[0050] The old asphalt recycling material is added to the flexible separator for crushing and screening to obtain coarse material with a particle size greater than 3mm and fine material with a particle size less than 3mm;

[0051] The coarse material is subjected to an asphalt stripping operation to strip and collect the old asphalt on the aggregate surface of the coarse material to obtain the old asphalt; the coarse material after the asphalt stripping is heated to 115° C. by a second countercurrent drum, and then screened by a vibrating screen, and stored in a coarse material storage tank to obtain recycled hot material;

[0052] The old asphalt and the fine material are mixed, and the mixture is fed into a first countercurrent drum and heated to 165° C. The mixture is then measured by a first flow meter and fed into a foaming machine. At the same time, the H2CO3 solution stored in the solution storage tank is pumped out by a solution pump, passes through a first two-position three-way valve, a third flow meter, and a one-way valve in sequence, and then enters the foaming machine. After 10 seconds, the stabilizer stored in the stabilizer storage tank is pumped out by a stabilizer pump, passes through a second two-position three-way valve, a fourth flow meter, and a control valve in sequence, and then enters the foaming machine for foaming and stirring by a stirring roller in the foaming machine. After the foaming is completed, foamed asphalt is obtained, wherein the stabilizer comprises aluminum silicate mineral, montan wax, sodium α-olefin sulfonate, and calcium stearate.

[0053] The tail gas generated during countercurrent thermal regeneration of coarse and fine materials is recovered by a bag dust collector and dust is removed to obtain recovered powder, which is stored in a powder tank. The unusable waste gas enters the processor through a pipeline for desulfurization treatment and is then humidified and discharged into the waste liquid pool.

[0054] The recycled hot material in the coarse material storage tank is measured by the second flow meter and then enters the mixing tank. At the same time, the foamed asphalt in the foaming machine is discharged from the bottom of the foaming machine and sprayed into the mixing tank through the pipeline. The recovered powder in the powder tank is measured by the fifth flow meter and then enters the mixing tank. The 3-aminopropyltriethoxysilane stored in the coupling agent storage tank is conveyed by the conveyor and then enters the mixing tank. They are mixed together and the warm-mixed foamed recycled asphalt is obtained.

[0055] Example 2

[0056] A warm mix foamed recycled asphalt is prepared by the following steps:

[0057] The old asphalt recycling material is added to the flexible separator for crushing and screening to obtain coarse material with a particle size greater than 3mm and fine material with a particle size less than 3mm;

[0058] The coarse material is subjected to an asphalt stripping operation to strip and collect the old asphalt on the surface of the aggregate of the coarse material to obtain the old asphalt; the coarse material after the asphalt stripping is heated to 110° C. by a second countercurrent drum, and then screened by a vibrating screen, and stored in a coarse material storage tank to obtain recycled hot material;

[0059] The old asphalt and the fine material are mixed, and the mixture is fed into a first countercurrent drum and heated to 160° C. The mixture is then measured by a first flow meter and fed into a foaming machine. At the same time, the H2CO3 solution stored in the solution storage tank is pumped out by a solution pump, passes through a first two-position three-way valve, a third flow meter, and a one-way valve in sequence, and then enters the foaming machine. After 10 seconds, the stabilizer stored in the stabilizer storage tank is pumped out by a stabilizer pump, passes through a second two-position three-way valve, a fourth flow meter, and a control valve in sequence, and then enters the foaming machine for foaming and stirring by a stirring roller in the foaming machine. After the foaming is completed, foamed asphalt is obtained, wherein the stabilizer comprises aluminum silicate mineral, montan wax, sodium α-olefin sulfonate, and calcium stearate.

[0060] The tail gas generated during countercurrent thermal regeneration of coarse and fine materials is recovered by a bag dust collector and dust is removed to obtain recovered powder, which is stored in a powder tank. The unusable waste gas enters the processor through a pipeline for desulfurization treatment and is then humidified and discharged into the waste liquid pool.

[0061] The recycled hot material in the coarse material storage tank is measured by the second flow meter and then enters the mixing tank. At the same time, the foamed asphalt in the foaming machine is discharged from the bottom of the foaming machine and sprayed into the mixing tank through the pipeline. The recovered powder in the powder tank is measured by the fifth flow meter and then enters the mixing tank. The 3-aminopropyltriethoxysilane stored in the coupling agent storage tank is conveyed by the conveyor and then enters the mixing tank. They are mixed together and the warm-mixed foamed recycled asphalt is obtained.

[0062] Example 3

[0063] A warm mix foamed recycled asphalt is prepared by the following steps:

[0064] The old asphalt recycling material is added to the flexible separator for crushing and screening to obtain coarse material with a particle size greater than 3mm and fine material with a particle size less than 3mm;

[0065] The coarse material is subjected to an asphalt stripping operation to strip and collect the old asphalt on the aggregate surface of the coarse material to obtain the old asphalt; the coarse material after the asphalt stripping is heated to 120° C. by a second countercurrent drum, and then screened by a vibrating screen, and stored in a coarse material storage tank to obtain a recycled hot material;

[0066] The old asphalt and the fine material are mixed, and the mixture is fed into a first countercurrent drum and heated to 170° C. The mixture is then measured by a first flow meter and fed into a foaming machine. At the same time, the H2CO3 solution stored in the solution storage tank is pumped out by a solution pump, passes through a first two-position three-way valve, a third flow meter, and a one-way valve in sequence, and then enters the foaming machine. After 10 seconds, the stabilizer stored in the stabilizer storage tank is pumped out by a stabilizer pump, passes through a second two-position three-way valve, a fourth flow meter, and a control valve in sequence, and then enters the foaming machine for foaming and stirring by a stirring roller in the foaming machine. After the foaming is completed, foamed asphalt is obtained, wherein the stabilizer comprises aluminum silicate mineral, montan wax, sodium α-olefin sulfonate, and calcium stearate.

[0067] The tail gas generated during countercurrent thermal regeneration of coarse and fine materials is recovered by a bag dust collector and dust is removed to obtain recovered powder, which is stored in a powder tank. The unusable waste gas enters the processor through a pipeline for desulfurization treatment and is then humidified and discharged into the waste liquid pool.

[0068] The recycled hot material in the coarse material storage tank is measured by the second flow meter and then enters the mixing tank. At the same time, the foamed asphalt in the foaming machine is discharged from the bottom of the foaming machine and sprayed into the mixing tank through the pipeline. The recovered powder in the powder tank is measured by the fifth flow meter and then enters the mixing tank. The 3-aminopropyltriethoxysilane stored in the coupling agent storage tank is conveyed by the conveyor and then enters the mixing tank. They are mixed together and the warm-mixed foamed recycled asphalt is obtained.

[0069] Comparative Example 1

[0070] Compared with Example 1, no stabilizer was added, and the remaining steps were the same.

[0071] Comparative Example 2

[0072] Compared with Example 1, 3-aminopropyltriethoxysilane was not added, and the remaining steps were the same.

[0073] Comparative Example 3

[0074] Compared with Example 1, the H2CO3 solution was replaced by water, and the remaining steps were the same.

[0075] Experimental example

[0076] The warm-mix foamed regenerated asphalt prepared in the examples and comparative examples of the present application was subjected to freeze-thaw cycle simulation. The freeze-thaw test method was adopted, and the water temperature was controlled at (15±1)°C to prepare a warm-mix foamed regenerated asphalt Marshall specimen. The warm-mix foamed regenerated asphalt Marshall specimen was vacuum-saturated with water for 30 minutes and then placed in a plastic bag. To ensure a moist environment in the bag, 10 mL of water was added, and the specimen was then placed in a -18°C environment and frozen for 16 hours. After freezing, it was placed in a constant temperature box at 15°C for 8 hours to complete a freeze-thaw cycle. The cycle was repeated 5 times, 10 times, 20 times, and 30 times.

[0077] 1. High temperature performance test

[0078] The standard Marshall test was used to characterize the high-temperature performance of warm-mix foamed recycled asphalt under different freeze-thaw cycles. The prepared warm-mix foamed recycled asphalt Marshall specimens were placed in a 60°C constant temperature water tank for 30 to 45 minutes, with a loading speed of (50 ± 5) mm / min. -1 , measure the stability of the corresponding specimens. The test results are shown in Table 1.

[0079] Table 1

[0080]

[0081]

[0082] It can be seen from Table 1 that with the increase of the number of freeze-thaw cycles, the Marshall stability of the warm-mix foamed regenerated asphalt decreases. After 15 freeze-thaw cycles, the Marshall stability of Comparative Example 1 and Comparative Example 2 is lower than the minimum standard of 8KN required by the specification. However, after 30 freeze-thaw cycles, the Marshall stability of the warm-mix foamed regenerated asphalt prepared in the embodiment of the present application is still above 8KN, indicating that the stabilizer and 3-aminopropyltriethoxysilane have a greater influence on the freeze-thaw resistance of the warm-mix foamed regenerated asphalt, and the H2CO3 solution can also improve the freeze-thaw resistance of the warm-mix foamed regenerated asphalt compared to water.

[0083] 2. Low temperature stability test

[0084] The Marshall specimen was compacted with a 12.7 mm wide strip, the temperature was controlled at -10°C ± 0.5°C, and the loading rate was 1 mm min -1 Before the test, the Marshall specimen was placed in a -10°C temperature-controlled box for at least 8 hours. After the internal and external temperatures of the specimen reached the test standard requirements, the specimen was quickly removed from the temperature-controlled box and placed in the splitting instrument. After the temperature was stabilized for 15 minutes, the splitting tensile strength test was started. The corresponding calculation formula is as follows:

[0085] RT=0.006287PT / h

[0086] Where: RT is the splitting tensile strength (MPa); PT is the maximum test load (N); h is the specimen height (mm).

[0087] The test results are shown in Table 2.

[0088] Table 2

[0089]

[0090]

[0091] As shown in Table 2, with the increase of freeze-thaw cycles, the low-temperature splitting strength of the warm-mix foamed regenerated asphalt decreases. In Comparative Example 1, no stabilizer is added, which affects the warm-mix foaming effect and makes the prepared warm-mix foamed regenerated asphalt unstable. In Comparative Example 2, no 3-aminopropyltriethoxysilane is added, and 3-aminopropyltriethoxysilane can react with water to form an organic siloxane film on the surface of the mineral powder, thereby enhancing the adhesion between the foamed asphalt and the mineral powder, slowing down the peeling of the asphalt and enhancing the splitting strength of the asphalt. Therefore, the low-temperature splitting strength of the warm-mix foamed regenerated asphalt in Comparative Example 2 increases with the increase of freeze-thaw cycles. The increase in the number of freeze-thaw cycles significantly reduces the splitting strength; in Comparative Example 3, water is used instead of H2CO3 solution for foaming, and the replacement of asphalt by water during the freeze-thaw cycle will cause the asphalt to fall off, resulting in a decrease in the adhesion between the asphalt and the mineral powder. As the number of freeze-thaw cycles increases, the internal damage of the mixture gradually accumulates, the porosity continues to increase, and the peeling of the asphalt intensifies, which is manifested as a decrease in splitting strength. H2CO3 can decompose to produce CO2, which can act as a foaming gas and enter the interior of the asphalt, causing the asphalt to continue foaming, reducing the porosity, and effectively improving the low-temperature splitting strength of the warm-mix foamed recycled asphalt.

[0092] 3. Foaming effect test

[0093] Warm-mix foamed regenerated asphalt prepared in the Examples and Comparative Examples of this application was stored for 48 hours, and then its expansion rate and half-life were measured. The expansion rate is the ratio of the maximum volume of the asphalt measured in the foamed state to the volume in the unfoamed state. A higher expansion rate indicates better quality of the foamed asphalt mixture. The half-life is the time it takes for the foamed asphalt to shrink from its maximum volume to half of that volume. It is used to evaluate the stability of the foamed asphalt. A longer half-life indicates that the foam is less likely to decay. The results are shown in Table 3 below.

[0094] Table 3

[0095] Group Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Expansion rate 25.3 23.2 22.7 9.7 13.9 15.8 Half-life 20.4 18.3 19.6 13.5 11.6 15.1

[0096] It can be seen from Table 3 that the expansion rate and half-life of the warm-mix foamed regenerated asphalt prepared in Comparative Examples 1-3 are significantly lower than those in the warm-mix foamed regenerated asphalt in the examples. Since the foaming effect of the foamed asphalt meets the requirements only when the expansion rate is greater than 10 and the half-life is less than 12s, it can be seen that the warm-mix foamed regenerated asphalt in Comparative Examples 1 and 2 does not meet the requirements, indicating that the stabilizer and 3-aminopropyltriethoxysilane have a greater influence on the asphalt foaming effect. In Comparative Example 3, water is used instead of H2CO3 as the foaming agent. Since H2CO3 is easily decomposed by heat, CO2 can be produced, which can act as a foaming gas and enter the interior of the asphalt, causing the asphalt to continue foaming. Therefore, the foaming effect of the warm-mix foamed regenerated asphalt in Comparative Example 3 is affected.

[0097] The above description is merely an optional embodiment of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made using the contents of the present application specification and drawings under the inventive concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A warm mix foamed regenerated asphalt production equipment, characterized in that: The invention comprises a flexible separator, a first countercurrent roller, a second countercurrent roller, a foaming machine, a solution storage tank, a stabilizer storage tank, a stirring tank and a coupling agent storage tank, wherein both ends of the flexible separator are connected to the first countercurrent roller and the second countercurrent roller respectively, the first countercurrent roller is connected to the foaming machine via a pipeline, the second countercurrent roller is connected to the stirring tank via a pipeline, the solution storage tank is connected to the upper side of the foaming machine via a pipeline, the stabilizer storage tank is connected to the lower side of the foaming machine via a pipeline, the outlet end of the foaming machine is connected to the stirring tank via a pipeline, and the coupling agent storage tank is connected to the stirring tank via a pipeline; The lower side of the stabilizer storage tank is connected to a stabilizer pump, the other end of the stabilizer pump is connected to a second two-position three-way valve, one side of the second two-position three-way valve is connected to the upper side of the stabilizer storage tank, the other side of the second two-position three-way valve is connected to a fourth flow meter, and a control valve is provided between the fourth flow meter and the foaming machine; Wherein, the solution storage tank contains H2CO3 solution; The stabilizer storage box stores stabilizers, wherein the stabilizers include aluminum silicate mineral, montan wax, sodium α-olefin sulfonate and calcium stearate; When the heating temperature in the foaming machine is 160-170° C., the H 2 CO 3 solution and the stabilizer are added to perform foaming, and the stabilizer is injected into the foaming machine 10 seconds later than the H 2 CO 3 solution.

2. The warm mix foamed regenerated asphalt production equipment according to claim 1, characterized in that: It also includes a bag dust collector, which is connected to the exhaust gas outlet end of the first countercurrent drum and the exhaust gas outlet end of the second countercurrent drum respectively. The exhaust gas end of the bag dust collector is connected to the processor, and the processor is connected to the waste liquid pool.

3. The warm mix foamed regenerated asphalt production equipment according to claim 2, characterized in that: The outlet end of the bag filter is connected to a powder tank, which is connected to the mixing cylinder through a pipeline. A fifth flow meter is provided between the powder tank and the mixing cylinder.

4. The warm mix foamed regenerated asphalt production equipment according to claim 1, characterized in that: A vibrating screen and a coarse material storage tank are connected to the second countercurrent drum and the mixing tank in sequence through pipelines, and a second flow meter is provided between the coarse material storage tank and the mixing tank.

5. The warm mix foamed regenerated asphalt production equipment according to claim 1, characterized in that: A solution pump is connected to the lower side of the solution storage tank, and the other end of the solution pump is connected to a first two-position three-way valve. One path of the first two-position three-way valve is connected to the upper side of the solution storage tank, and the other path of the first two-position three-way valve is connected to a third flow meter. A one-way valve is provided between the third flow meter and the foaming machine.

6. A warm mix foamed regenerated asphalt production process, characterized in that: The warm mix foamed regenerated asphalt production equipment according to any one of claims 1 to 5 comprises the following steps: After the old asphalt recycling material is crushed and screened by a flexible separator, coarse material with a particle size greater than 3mm and fine material with a particle size less than 3mm are obtained respectively; The coarse material is subjected to an asphalt stripping operation to strip and collect the old asphalt on the surface of the aggregate of the coarse material to obtain the old asphalt; the coarse material after the asphalt stripping is heated to 110-120°C by a second countercurrent drum, and then screened by a vibrating screen to obtain the recycled hot material; The old asphalt and the fine material are mixed and put into the first countercurrent drum and heated to 160-170°C. Then, the old asphalt and the fine material are put into the foaming machine. At the same time, the H2CO3 solution in the solution storage tank and the stabilizer in the stabilizer storage tank are added into the foaming machine for foaming and stirring by the stirring roller in the foaming machine. After the foaming is completed, foamed asphalt is obtained. The tail gas generated when the coarse material and the fine material are heated is processed by a bag dust collector to obtain a recovered powder; The regenerated hot material, the foamed asphalt and the recycled powder are mixed in a mixing tank, and the coupling agent in the coupling agent storage tank is added into the mixing tank for stirring to obtain warm-mixed foamed regenerated asphalt.

7. The warm mix foamed regenerated asphalt production process according to claim 6, characterized in that: The step of treating the tail gas generated when the coarse material and the fine material are heated by a bag dust collector includes: recovering the tail gas generated when the coarse material and the fine material are heated by a bag dust collector and removing dust to obtain recovered powder and waste gas, desulfurizing the waste gas in a processor, and storing the waste gas in a waste liquid pool after treatment.

8. The warm mix foamed regenerated asphalt production process according to claim 6, characterized in that: The coupling agent is 3-aminopropyltriethoxysilane.

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