CN114481749A

CN114481749A - Hot plant-mixing regeneration premixing step-by-step mixing control method for old asphalt material

Info

Publication number: CN114481749A
Application number: CN202210251024.9A
Authority: CN
Inventors: 宋小金; 吴超凡; 王亚平; 谈忠坤; 潘勤学; 樊亮; 董昭
Original assignee: Hunan Huacheng Testing Technology Co ltd
Current assignee: Hunan Huacheng Testing Technology Co ltd
Priority date: 2022-03-15
Filing date: 2022-03-15
Publication date: 2022-05-13
Anticipated expiration: 2042-03-15
Also published as: CN114481749B

Abstract

The invention discloses a plant-mixing hot recycling pre-mixing step-by-step mixing control method for old asphalt materials, which solves the problem of asphalt aging in the prior art. The method comprises two important improvement steps of precooling and cutting carbon fiber filaments, wherein an old asphalt material is put into a cold water pool, and is soaked in cold water to carry out cold exchange between the old asphalt material and the cold water, so that the temperature of the old asphalt material is reduced to be within the range of 0-5 ℃; putting the new aggregate into a No. 1 rotary kiln for heating, putting RAP into a No. 2 rotary kiln for heating, wherein the temperature of the heated new aggregate is not lower than 200 ℃, the best is 220 ℃, the temperature of the RAP is not higher than 80 ℃, adding a regenerated SBS modified old asphalt material modifier and cut carbon fiber yarns into the No. 2 rotary kiln, and stirring; the invention realizes the purpose of premixing and mixing step by step through mixing of the mixing pot, heat-preservation spiral conveying and mixing of the mixing plant, improves the mixing uniformity, reduces the high-temperature time period of the asphalt and is beneficial to the maintenance of the high performance of the asphalt.

Description

Hot plant-mixing regeneration premixing step-by-step mixing control method for old asphalt material

Technical Field

The invention relates to the technical field of hot plant recycling production of old asphalt materials.

Background

The regeneration technology of old asphalt materials is a technology of milling, recovering, crushing and screening old asphalt pavements, then re-mixing the old asphalt pavements with a regenerant, a new asphalt material, a new aggregate and the like according to a certain proportion to form a mixture meeting a certain pavement performance, and re-paving the mixture on the pavements.

The technical route comprises on-site regeneration and plant-mixed regeneration, and can also be divided into hot regeneration and cold regeneration. The plant mixing heat regeneration is the key point of research and development of all units at present, and the research and development of the plant mixing heat regeneration technology are important subjects about the highway maintenance technology and the recycling rate of renewable resources in China.

The application of the plant mixing heat regeneration technology has four difficulties at present:

first, in the process of breaking old asphalt materials obtained by milling, jaw crushers, impact crushers or hammer crushers are adopted at present, the efficiency of the jaw crushers, the impact crushers or the hammer crushers is high, but in the crushing process, the existence of shearing force can cause the temperature rise of the old asphalt materials, the uniformity of crushed particles is poor, and the crushing force is great.

Secondly, RAP (reclaimed asphalt) in the old asphalt material is heated. In the plant-mixed hot recycling production process, RAP needs to be heated, and the heating process generally adopts a fuel nozzle heating mode to exchange heat. Theoretically, the uniform heating process is more beneficial to asphalt stabilization, and in practice, factors such as the heating temperature of RAP in the rotary kiln, the selection of the heating mode, whether the heated structure is reasonable and the like have great influence on the stability of the finished product materials in the later period, the running reliability and the continuity of equipment. Therefore, in the process of making the process, the problems of the selection of the heating mode and the heating equipment are particularly emphasized.

Thirdly, the RAP bonding problem is a derivative problem of the plant mixing hot recycling technology, and from the moment when the RAP temperature is increased, the bonding problem restricts the whole production process. The problem of bonding exists in rotary kilns, temporary storage bins and conveying channels. The reclaimed tack of asphalt has a positive side that is bi-directional and a negative side. Among them, asphalt is heated to reduce its adhesiveness, and the asphalt is repeatedly heated to change its mechanism and chemical composition, thereby reducing its adhesiveness. Meanwhile, the bonding performance of the adhesive is reduced due to dust pollution and impurity introduction in the production field. Therefore, the problem of the reduction of the bonding performance of the waste asphalt material is particularly solved in the process of process formulation.

Fourthly, the asphalt smoke and the asphalt reclaimed materials can generate the asphalt smoke after being heated, and the influence factors are numerous, wherein the heating temperature is the main factor influencing the chemical components of the asphalt smoke. The asphalt smoke pollutes the environment, and the collection and the treatment of the asphalt smoke are very difficult. At present, the collection and treatment commonly used are incineration, mechanical separation, spray tower water film washing, activated carbon adsorption, electric dust removal, and the like. In the current engineering practice, several methods are adopted and used for reducing the emission of the asphalt smoke to the maximum extent, but neither method can reduce the generation of the asphalt smoke from the source.

Disclosure of Invention

The invention mainly aims to provide a plant-mixing hot-recycling pre-mixing step-by-step mixing control method for old asphalt materials, provides a new process route under the condition of keeping the asphalt caking property as much as possible not to be reduced, and solves the defects in the technical background.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the plant-mixing hot recycling premixing step-by-step mixing control method for the old asphalt material comprises the following steps in sequence:

s1: putting an old asphalt material into a cold water pool, installing a scraper conveyor belt in the cold water pool, arranging the scraper conveyor belt along the length direction of the cold water pool, putting the old asphalt material obtained by milling and planing on the scraper conveyor belt in the cold water pool, wherein the scraper conveyor belt is partially immersed in cold water and slowly runs, and the old asphalt material and the cold water are subjected to cold exchange through immersion in the cold water, so that the temperature of the old asphalt material is reduced to be within the range of 0-5 ℃;

s2: the method comprises the following steps of putting low-temperature old asphalt materials into a centrifugal impact crusher, enabling the centrifugal acceleration of the centrifugal impact crusher to be not lower than 5G, enabling the speed of the materials to be not lower than 100 m/s after acceleration, enabling impact crushing effect to be achieved due to obvious increase of brittleness of the low-temperature old asphalt materials, and then screening the crushed materials to obtain RAP materials with different particle size specifications;

s3: respectively stacking RAP materials with different granularity specifications in different bins to be in a standby state;

s4: randomly sampling and detecting the modifiers of the new aggregate, the new asphalt and the asphalt regenerated SBS modified old asphalt materials;

s5: designing mineral aggregate gradation, wherein gradation parameters meet the relevant technical specifications of pavement construction, and the process is developed based on data obtained by a laboratory and the requirements of the technical specifications;

s6: heating in a rotary kiln, putting the new aggregate into a No. 1 rotary kiln for heating, putting RAP into a No. 2 rotary kiln for heating, wherein the temperature of the heated new aggregate is not lower than 200 ℃, the best is 220 ℃, the temperature of the heated RAP is not higher than 80 ℃, adding a regenerated SBS modified old asphalt material modifier and cut carbon fiber filaments into the No. 2 rotary kiln, and stirring;

s7: putting the new aggregate and RAP generated in the step S3 into a mixing pot according to the grading proportion for premixing, wherein the premixing time is strictly controlled in the premixing process, and the mixing time is controlled within 1 minute;

s8: adding new asphalt in a conveying path of a heat-insulating spiral elevator before entering a mixing plant, and realizing secondary step-by-step mixing of materials by utilizing a spiral lifting process;

s9: after being mixed, the mixture is transported to a paving site in a heat preservation state for paving.

The mixing plant and the mixing pot are designed to be inert gas space, so that the generation amount of asphalt smoke is reduced from the source.

The cold water pool is provided with a circulating filtration and purification system.

The cold water in the cold water pool is in the state of ice-water mixture.

And (4) extracting asphalt from the asphalt tank by using a heat-preservation three-screw pump and conveying the asphalt into a conveying path of a heat-preservation screw elevator.

The centrifugal impact type crusher can be divided into two parts which are connected in series.

The centrifugal impact crusher has a dewatering function for generating RAP by crushing.

The invention has the beneficial effects that:

one of innovations is that the centrifugal impact crusher is used for cooling and centrifugally crushing the recovered blocky old asphalt material for the first time, so that the mechanical damage of the traditional jaw crusher to particles in the old pavement material is avoided, the integrity of the particles is favorably maintained, and the performance of new raw materials is favorably maintained.

And secondly, the invention effectively reduces the generation amount of asphalt smoke from the source and is more environment-friendly by implementing far infrared heating transformation and inert environment transformation on the rotary kiln.

Thirdly, the invention realizes the purpose of premixing and mixing step by step through mixing of a mixing pot, heat preservation screw conveying mixing and mixing of a mixing plant, improves the mixing uniformity, reduces the high-temperature time period of the asphalt and is beneficial to the maintenance of the high performance of the asphalt.

Drawings

FIG. 1 is a process diagram of the present invention.

FIG. 2 is a system diagram of the present invention.

Detailed Description

The conventional mixing in the traditional process refers to a process route of mixing RAP, new aggregate, new asphalt and the like all at once, and has the defects of long heating time, long mixing process, poor uniformity, reduced asphalt performance, more asphalt smoke and the like.

In order to improve the binding property of the mixture, reduce the generation amount of asphalt smoke and avoid the degradation and layer lowering of waste asphalt pavement materials, the invention provides a plant-mixing hot regeneration process for regenerating old asphalt materials, and the comprehensive binding property is improved by adopting effective control of pre-mixing and step-by-step mixing.

The premixing and sub-step mixing in the embodiment refers to that the original mixing process is divided into a plurality of sub-steps, mixing objects and mixing environments in each step are different, and fine screening of mixed materials is improved through the design of the sub-steps. And through reasonable arrangement of the inert gas supplementing system, the generation amount of asphalt smoke is reduced from the source, the subsequent asphalt smoke treatment investment is reduced, and the environment is protected.

The waste asphalt material obtained by milling and other recovery is mainly composed of asphalt, coarse aggregate, fine aggregate, mineral powder and a small amount of impurities (including but not limited to dust and gravel), and is called as the waste asphalt material in this embodiment. Because various materials in the old asphalt materials are uniformly distributed, the old asphalt materials can not be directly used by simply recycling the old asphalt materials. The process comprises the steps of firstly carrying out premixing such as fine screening and impurity removal or primary RAP, and then mixing with new aggregate, new asphalt and cut carbon fiber yarns step by step to form a regenerated old asphalt material meeting the requirement of engineering paving.

After the pre-mixing step-by-step mixing process of the embodiment, the mixing components of a specific recycled old asphalt material comprise the following components in percentage by mass: 71 to 75 percent of RAP, 20 to 25 percent of new aggregate, 7 to 8 percent of new asphalt, 0.01 to 0.3 percent of cut carbon fiber filament and 0.1 to 0.2 percent of regenerated SBS modified old asphalt material modifier; the dosage of each component can be selected in a given range according to actual needs, the total amount is 100 percent, and the length of the cut carbon fiber filament is controlled between 2 centimeters and 8 centimeters. The segmented carbon fiber yarns are obtained from various existing waste recycled industrial products, such as various disassembled carbon fiber fan blades and the like, and are obtained through full cracking and segmentation, and the implementation of the process also increases a carbon fiber waste utilization channel and is environment-friendly. If the conditions do not allow, the cut carbon fiber yarns can be omitted.

The RAP described in this embodiment is a material that is obtained by a mixing station through a crushing and screening process using a crushing device and a screening device, and the obtained RAP contains asphalt, coarse aggregate, fine aggregate, mineral powder and a small amount of impurities (including but not limited to dust and gravel). In the process, a low-temperature cracking process is adopted, adverse effects on the performance of the asphalt in the RAP are avoided by introducing the low-temperature cracking process, the granularity is kept favorably, and the specific process is elaborated in detail in the subsequent implementation process.

The new aggregate is used for common highways, and the proper particle size is selected according to the actual engineering requirements.

The new asphalt is used as an additive to make up for the defect of the reduced bonding property of RAP.

The regenerated SBS modified old asphalt material modifier mainly contains SBS, a tackifying component, a compatibilization component and the like, and is used for improving the adhesive property of old asphalt materials. For example, as a general alternative, the old SBS modified asphalt modifier can be a GN-01 asphalt high viscosity additive or a RMA thermal recycling composite modifier in Hunan-Crossful-department, which is merely an example and is not limited by manufacturers and brands.

For the convenience of further understanding of the technical scheme of the invention, the method for controlling the mixing of the old asphalt material by hot plant recycling and pre-mixing step by step is illustrated as follows:

example 1

Referring to fig. 1 and 2, the process of this example is described from the beginning of milling and the end of recycling the asphalt mix:

(1) precooling is first performed by a loading hopper 10 into which the old material is unloaded by a truck 10. Adding a step of cooling the recovered blocky materials, specifically, adding a rectangular cold water tank 20, installing a scraper conveyor belt 21 in the cold water tank, arranging the scraper conveyor belt along the length direction of the cold water tank, and putting the blocky materials obtained by milling into the scraper conveyor belt in the cold water tank through a storage bin, wherein the scraper conveyor belt is partially immersed in cold water, and performing cold exchange between the blocky materials and the cold water by soaking in the cold water to reduce the temperature of the blocky materials to be within the range of 0-5 ℃, wherein the best cold water is in an ice water mixture state. The low temperature state is more beneficial to the crushing of the blocky pavement materials. The waste asphalt material in the low-temperature state has stronger brittleness, the crushing effect is easier to generate in the process of impacting the inner wall in the centrifugal impact crusher, the crushing efficiency is improved, and the original granularity and viscosity of the asphalt and the blocky materials are kept.

The cold water soaking process can further clean the blocky materials, improve the cleanliness of RAP materials and improve the bonding performance of the constructed pavement.

The cold water is subjected to circulating filtration and purification treatment, the turbid cold water can enter the filtering system 22 for recycling, and a water purification system is introduced into the system to basically prevent wastewater from being discharged.

By implementing the precooling process, the problem that the centrifugal crushing equipment cannot be efficiently applied in RAP material treatment is synchronously solved.

(2) Centrifugal crushing and screening

A centrifugal impact crusher 30 is installed at the discharge end of the cold water tank and is used for crushing the cooled materials. The centrifugal acceleration of the centrifugal impact crusher is up to 10G, and the speed of the material after acceleration is up to 200 m/s, so that the blocky material can be completely cracked at one time. The concrete process is, microthermal material gets into this equipment from the top blanking mouth of breaker, then the material is accelerated by high-speed rotatory centrifugal flywheel to throw away striking equipment inner wall, form effectual the explaiing. In the process, the centrifugal impact crusher replaces the traditional jaw crusher and plays a role in breaking a hammer and the like, the materials are crushed by being impacted with equipment, and the crushing process does not generate heat or generates heat very little, so that the physical performance of the materials is influenced minimally.

Meanwhile, in the centrifugal cracking process, along with the natural temperature rise of the low-temperature material, the temperature rise range is limited and is generally lower than the ambient temperature.

Further, if the crushing effect of one centrifugal impact crusher is not ideal, secondary centrifugal crushing can be performed according to design requirements, so that particles generated by centrifugal crushing are finer, and the technical requirements of secondary use are met.

Further, after the preliminary impact, screening is carried out to form 1# RAP and 2# RAP with the thickness of 16-30 mm, 1-16 mm and 0-1 mm and powder, and the screened material is basically in a normal temperature state.

For the processing of the RAP, it is also conceivable to use more screens for classification after crushing it in the mixing plant, e.g. to divide the crushed material into multiple stages after screening. After being crushed and screened and the gradation meets the production requirement, the materials can be sent to a mixing plant for production, and can also be stacked and stored for later use.

The centrifugal crushing process is combined with the cold water soaking process, the material temperature is low, the temperature rise problem of the RAP material in the crushing process of the traditional crusher is solved, the problem that the RAP material is easy to agglomerate again under the combined action of the dead weight, the temperature and the old asphalt is reduced, and the centrifugal crushing process has positive significance for improving the quality of the RAP. Meanwhile, the method has positive significance for preventing the asphalt from being aged continuously, and the old material from being segregated, hardened or agglomerated and ensuring the quality stability of the old material.

The above centrifugal crushing process also achieves the preliminary dehydration of the RAP so that the RAP is in a substantially dehydrated state.

(3) Separate storehouse stacking

And (3) uniformly stacking the 1# RAP, the 2# RAP and the powder obtained in the step (2) in different bins respectively, wherein the RAP and the powder are in a standby state, and the temperature of the RAP is mainly influenced by the air temperature and is not greatly fluctuated during the storage period. Wherein, the design of feed bin satisfies conventional design can.

Further the above-mentioned # 1 RAP, # 2 RAP and powder are respectively lifted by different lifts 40 and stored in dedicated silos 41 for standby.

(4) Raw material detection

The quality of the selected materials such as new aggregate, new asphalt and the like is randomly sampled and detected, and each index needs to meet the requirements of technical Specifications for road asphalt pavement regeneration (JTG/T5521-2019) and technical Specifications for road asphalt pavement construction (JTG F40-2004).

Selecting two grades of RAP and powder in the step (2), extracting and screening, and respectively carrying out performance tests on the extracted and recovered old asphalt and old aggregate, wherein each index needs to meet the requirements of technical Specification for road asphalt pavement regeneration (JTG/T5521-2019);

and screening the old aggregate to obtain the mineral aggregate gradation. The more the grades are, the more stable the grading of the regenerated mixture is, and the grade number is 2-5 grades.

Selecting new asphalt and an asphalt regenerated SBS modified old asphalt material modifier, and performing performance test on the regenerated SBS modified old asphalt material modifier, wherein the new asphalt can be common SBS modified asphalt or high-viscosity asphalt. The selected new asphalt is SBS modified asphalt, the regenerated SBS modified old asphalt material modifier is GN-01 asphalt high-viscosity additive in Xiang Jiake department, and all indexes need to meet the requirements of technical Specifications for road asphalt pavement regeneration (JTG/T5521-2019) and technical Specifications for road asphalt pavement construction (JTG F40-2004).

(5) Grading design

According to specific engineering requirements, mineral aggregate gradation is designed, gradation parameters meet related pavement construction technical specifications, and the process is developed based on data obtained by a laboratory and the technical specification requirements.

(6) Heating in a rotary kiln, firstly selecting an RAP material in a 1# RAP and 2# RAP storage bin and a new aggregate (broken stone, gravel, sand, slag and the like) in a new aggregate storage bin to be mixed according to the grading requirement, wherein the mixing place is the rotary kiln 50, the quantity of the rotary kiln is two, the new aggregate and the RAP are heated in advance before mixing, and the temperature of the heated new aggregate is slightly higher than 220 ℃ (the optimal temperature range is 200-230 ℃) and the RAP temperature is slightly lower than 80 ℃. Low-temperature RAP has certain fluidity, so that the RAP is not adhered to the wall of the hopper, and the adhesion effect caused by overhigh RAP temperature in the traditional process is effectively solved.

In the heating process, the temperature of the new aggregate is obviously higher than 220 ℃, more heat energy is stored in the new aggregate, the new aggregate does not contain asphalt components, heat exchange can be carried out between the new aggregate and the RAP in the subsequent mixing process of the new aggregate and the RAP, the new aggregate and the RAP reach the new heat balance, and meanwhile, the new aggregate with higher temperature has the effect of locally and quickly melting the asphalt on the surface layer of the RAP material.

In the heating process, the new aggregate is heated by a rotary kiln No. 1, the RAP is heated by a rotary kiln No. 2 to form different heating temperatures, the regenerated SBS modified old asphalt material modifier is added into the rotary kiln No. 2 to be uniformly mixed, the cut carbon fiber filaments are mixed with the RAP in the rotary kiln No. 2, the cut carbon fiber filaments and the RAP surface in the rotary kiln No. 2 have an adhesion effect, and the temperature of the RAP is controlled below 80 ℃, so that the cut carbon fiber filaments are attached to the RAP particle surface.

After the cut carbon fiber yarns are added into asphalt, the cut carbon fiber yarns are directly contacted with new aggregates with higher temperature, so that the flexibility of the cut carbon fiber yarns is increased, and the tensile property of the asphalt is improved under the adhesion state of the asphalt on the surface.

The cutting length in the present embodiment is preferably within 10 cm, for example, 3 cm or 5 cm.

The old asphalt material is granular in original state, is still in a granular non-sticky state at 80 ℃, has better trafficability in a rotary kiln, and solves the adhesion defect of the old asphalt material in a No. 2 rotary kiln.

(7) Mixing in a mixing pot

And (3) putting the new aggregate and RAP generated in the step (6) into a mixing pot (60) according to the grading proportion for premixing, wherein the premixing time is strictly controlled in the premixing process, the total mixing time is controlled within 1 minute, heat exchange is generated between the high-temperature new aggregate and the RAP material with the second high temperature in the mixing process, the mixing pot does not need to be heated in the process, the temperature of the mixed material after mixing is controlled between 120 and 140 ℃, and the mixed material is randomly conveyed to the subsequent process.

In the traditional process, the theoretical heating temperature (discharge temperature) of the RAP should be between 120 to 140 ℃, this embodiment breaks through the above limitation, pre-softening is performed on old asphalt materials by adopting a temperature reduction mode, after the old pre-softened asphalt materials are mixed with new aggregates up to 220 ℃, heat exchange is completed in the mixing process, so that the temperature of the mixed old asphalt materials reaches the optimal 120 to 140 ℃ temperature range, through direct mixing of two materials with different temperatures, the high temperature time period of the old asphalt materials is shortened, the high temperature aging of asphalt can be effectively prevented, and this is for improvement.

In the process, the proportion of various materials is controlled by the matching of the opening degree of the gate and the meter.

And then, using a heat-preservation spiral elevator with a heat-preservation function to perform height lifting, wherein the heat-preservation spiral elevator is a measure of adding a heat-preservation layer on the outer side of a conveying cylinder of a conventional spiral conveyor. So that the internal materials are in a heat preservation state in the conveying process.

In the mixing process, the RAP temperature is increased, and the cut carbon fiber filaments are further attached between RAP particles and new aggregate particles, so that the adhesion enhancing effect is achieved.

(8) Spirally lifted mixing

Before entering a mixing plant, a procedure of adding new asphalt in a conveying path of the heat-preserving spiral elevator 70 is added, the spiral lifting process is fully utilized, secondary step-by-step mixing of materials is realized, meanwhile, the implementation of the procedure effectively reduces the mixing time in the mixing plant procedure, and the reduction of the mixing time has positive significance for reducing the aging of the asphalt.

For example, the asphalt is pumped from an asphalt tank by a heat-insulating three-screw pump, fed into an asphalt weighing scale to be metered, uniformly added in a conveying path of a heat-insulating screw elevator until the asphalt is conveyed to a mixing plant, and mixed uniformly.

Meanwhile, the new asphalt is added into the heat-preservation spiral lifting channel in proportion and is fully mixed with the mixture, and compared with the traditional mode of directly adding the new asphalt into a mixing plant, the method has positive significance in shortening the mixing time of the mixing plant.

(9) Mixing in a mixing plant

The mixture is conveyed to a mixing plant 80 and is mixed evenly, the process is compressed to about 1 minute, and because the mixing time of the step is compressed, the process preferably uses mixing plant equipment with continuous mixing function, and the production can be continuous. The mixing time is shortened, the defects caused by asphalt aging can be avoided, and the method has positive significance for maintaining the performance of asphalt materials.

And finally, transporting the concrete to a paving site in a heat preservation state for paving.

Example two

The rotary kiln in this embodiment adopts countercurrent heating, including rotary kiln, far infrared heating rod, and the discharge end of rotary kiln is adopted in this far infrared heating rod installation, adopts the mode of rolling + cloud infrared heating to heat the old material of pitch. The heating mode has the advantages that the heat exchange efficiency is extremely high, the temperature of the reclaimed materials can be quickly raised, the electric heating is adopted, open fire is avoided, the reduction of the content of asphalt smoke is facilitated, and a large amount of radiant heat can be fully utilized.

Further, carry out dynamic seal in foretell # 2 rotary kiln to at the external one set of nitrogen gas replenishing device that increases of rotary kiln, this nitrogen gas replenishing device carries out the supplementary nitrogen gas to # 2 rotary kiln inside, forms the environment of inertia, avoids or reduces the oxidation reaction of pitch and oxygen, is favorable to reducing the oxidation of pitch, reduces the output of pitch cigarette from the source.

Further, carry out dynamic seal in foretell blending pot and the blending plant to increase a set of nitrogen gas replenishing device in the rotary kiln external world, this nitrogen gas replenishing device carries out the supplementary nitrogen gas to 2# rotary kiln inside, forms inert environment, is favorable to reducing the activity of pitch, reduces the output of pitch cigarette from the source.

A batching conveying system based on above-mentioned technology: the device comprises a centrifugal impact crusher, a storage bin, a belt feeder, a belt conveyor, a cold vibration sieve, a rotary kiln, a heat-preservation spiral elevator, a metering weighing hopper, a mixing pot, a mixing plant, a tail gas treatment module and an electric control system.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention and do not limit the scope of the present invention, and various modifications and improvements of the present invention by those skilled in the art without departing from the spirit of the present invention are intended to fall within the scope of the present invention defined by the claims.

Claims

1. The plant-mixing hot recycling premixing step-by-step mixing control method for the old asphalt material comprises the following steps in sequence:

s2: throwing low-temperature old asphalt materials into a centrifugal impact crusher, wherein the centrifugal acceleration of the centrifugal impact crusher is not lower than 5G, the speed of the accelerated materials is not less than 100 m/s, and then screening the crushed materials to obtain RAP materials with different granularity specifications;

s4: randomly sampling and detecting the modifiers for the new aggregate, the new asphalt and the asphalt regeneration SBS modified old asphalt material;

s6: heating in a rotary kiln, putting the new aggregate into a No. 1 rotary kiln for heating, putting RAP into a No. 2 rotary kiln for heating, putting RAP into the No. 2 rotary kiln for heating, and adding a regenerated SBS modified old asphalt material modifier and cut carbon fiber yarns into the No. 2 rotary kiln for stirring, wherein the temperature of the heated new aggregate is not lower than 200 ℃;

s7: putting the new aggregate and RAP generated in the step S3 into a mixing pot according to the grading proportion for pre-mixing, wherein the mixing time is controlled within 1 minute in the pre-mixing process;

2. The method for controlling the stepwise mixing and mixing of the hot plant recycling ready-mixed old asphalt material according to claim 1, wherein the method comprises the following steps: and filling inert gas into the mixing space of the mixing plant and the mixing pot.

3. The method for controlling the stepwise mixing of the hot mix plant recycling ready-mix of the old asphalt material according to claim 1, which is characterized by comprising the following steps: the cold water pool is provided with a circulating filtration and purification system.

4. The method for controlling the stepwise mixing and mixing of the hot plant recycling ready-mixed old asphalt material according to claim 1, wherein the method comprises the following steps: the cold water in the cold water pool is in the state of ice-water mixture.

5. The method for controlling the stepwise mixing and mixing of the hot plant recycling ready-mixed old asphalt material according to claim 1, wherein the method comprises the following steps: and (4) extracting asphalt from the asphalt tank by using a heat-preservation three-screw pump and conveying the asphalt into a conveying path of a heat-preservation screw elevator.

6. The method for controlling the stepwise mixing and mixing of the hot plant recycling ready-mixed old asphalt material according to claim 1, wherein the method comprises the following steps: the centrifugal impact type crusher comprises two centrifugal impact type crushers which are sequentially connected in series.

7. The method for controlling the stepwise mixing and mixing of the hot plant recycling ready-mixed old asphalt material according to claim 1, wherein the method comprises the following steps: the centrifugal impact crusher has a dewatering function for generating RAP by crushing.