A method and system for intelligent control of process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling process.

Abstract

This invention discloses an intelligent control method and system for the process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling, relating to the field of road engineering technology. It includes: S1: Dividing the pavement to be recycled into multiple pavement units, determining the dynamic heat transfer coefficient and heat retention time corresponding to each pavement unit through multi-dimensional data collection, and adjusting the energy output mode of the heating machine; S2: Obtaining the optimal parameter set corresponding to the remixing host through a constructed multi-objective optimization control model and objective function, and dynamically adjusting the optimal parameter set according to the heat retention time; S3: Collecting the discharge temperature and real-time apparent viscosity of the mixture, and determining the corresponding compensation action by comparing the results with preset temperature threshold ranges and preset viscosity threshold ranges. This invention improves the compaction degree of the recycled pavement, reduces the incidence of early-stage defects such as rutting and cracking, and significantly extends the service life of the pavement.

Description

Technical Field

[0001] This invention relates to the field of road engineering technology, specifically to an intelligent control method and system for the process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling. Background Technology

[0002] As a core component of modern transportation infrastructure, asphalt pavement's performance directly impacts driving safety, comfort, and the road's life-cycle cost. SBS (styrene-butadiene-styrene block copolymer) modified asphalt, with its excellent high-temperature rutting resistance, low-temperature crack resistance, and elastic recovery properties, is widely used in the surface paving of high-grade highways and urban arterial roads. However, during long-term service, SBS modified asphalt pavement is inevitably affected by the coupled influence of multiple environmental and mechanical factors, including ultraviolet radiation, oxygen oxidation, moisture intrusion, and repeated traffic loads, leading to severe physical and chemical aging of the material. Specifically, ultraviolet energy excites the carbon-carbon double bonds in SBS molecules, initiating chain breakage and cross-linking reactions, damaging the polymer network structure; oxygen attacks the butadiene segments, generating polar oxygen-containing functional groups such as carbonyl and carboxyl groups, causing an imbalance in the asphalt colloidal structure, increased viscosity, and a significant decrease in flexibility. This aging and deterioration manifests as cracks, potholes, loosening, and rutting on the pavement, severely weakening its structural strength and service function.

[0003] To extend road lifespan and achieve resource recycling, in-situ thermal recycling technology has been widely used as a green, environmentally friendly, and economical preventative maintenance method. This technology involves heating and softening the old pavement using specialized equipment, milling and loosening it, adding recycling agents and new asphalt mixtures, and then hot-mixing, paving, and compacting to form a recycled surface layer. Among these, the remixing recycling process, due to its ability to more fully adjust gradation and restore asphalt properties, is suitable for scenarios with deep damage or requiring improved structural strength, and has become a current research hotspot. Although traditional in-situ thermal recycling technology has accumulated some experience in engineering practice, many technical bottlenecks and challenges remain in the remixing recycling process for SBS modified asphalt.

[0004] Chinese invention patent CN120447403A discloses a method for adaptive speed adjustment in tomato transportation based on road condition feedback. The method includes: acquiring road images, vibration waveforms, and altitude data through a multi-source sensing unit to construct real-time road condition information; identifying driving modes and extracting corresponding bump parameters; combining multispectral and thermal imaging to detect tomato maturity levels and calculating cargo damage thresholds by querying a maturity-compressive strength correspondence table; constructing a dynamic mapping model under multiple operating conditions to predict vibration response and convert it into equivalent pressure; comparing the equivalent pressure with the damage threshold to obtain a safety margin; constructing a speed adjustment decision tree and generating the maximum permissible speed value for each road segment; and dynamically generating segmented speed control commands based on the speed decision matrix to control the coordinated speed change of the throttle and braking system. This invention has advantages such as accurate operating condition identification, dynamic fruit adaptation, and closed-loop speed control, making it suitable for precise speed control in highly sensitive fruit and vegetable transportation scenarios.

[0005] However, the above-mentioned and similar technical solutions still have the following shortcomings: In actual 100-meter-level working conditions, the construction speed of existing in-situ thermal recycling units inevitably fluctuates due to the ultra-long working distance and the interference of complex road conditions such as climbing and avoidance. This causes the residence time of the same road surface in the whole process of "heating-loosening-mixing-paving" to change non-linearly. At the same time, since SBS modified asphalt is sensitive to temperature, speed fluctuations will disrupt its construction temperature window. As a result, when decelerating uphill, the road surface is prone to thermal oxidative aging of SBS modifier due to excessive heating. When accelerating downhill, insufficient heating time and short mixing residence time will cause the mixture temperature to drop sharply and the compaction work to be insufficient. Consequently, the mixture has exceeded the optimal temperature mixing window when it reaches the rolling stage, which seriously affects the compaction degree and long-term service performance of the recycled pavement. Summary of the Invention

[0006] The purpose of this invention is to provide an intelligent control method and system for the process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for intelligent control of process parameters for in-situ hot recycling of SBS modified asphalt pavement, comprising: S1: Spatiotemporal mapping reconstruction temperature control: Through the vehicle-mounted multi-source sensing system, relevant multi-dimensional data is collected and acquired. At the same time, the road surface to be regenerated is divided into multiple road surface units. Through the multi-dimensional data, the dynamic heat transfer coefficient and heat retention time corresponding to the road surface unit are determined. Based on the dynamic heat transfer coefficient and heat retention time, the energy output mode of the heater is adjusted. S2: Coordinated adjustment of compound mixing adaptation: By constructing a multi-objective optimization control model and objective function, the optimal parameter set corresponding to the compound mixing host is obtained, and the rotor tip linear velocity and cavity filling rate in the optimal parameter set are dynamically adjusted according to the thermal residence time. S3: Real-time compensation of gradation heat capacity: Collect the discharge temperature and real-time apparent viscosity of the mixture from the discharge port of the mixing host, and determine the corresponding compensation action by comparing the results with the preset temperature threshold range and preset viscosity threshold range.

[0008] Furthermore, the energy output mode of the heater is adjusted, including: S1.1: Data Mapping: Through the vehicle-mounted multi-source perception system, relevant multi-dimensional data are collected in real time. At the same time, based on the multi-dimensional data, the dynamic heat transfer coefficient and heat retention time of the road unit are determined, and the corresponding SBS thermo-oxidative aging index and temperature drop gradient are extracted. S1.2: Operating condition processing: The thermal retention time and the longitudinal slope angle in the multi-dimensional data are compared with the preset time threshold range and the preset slope threshold range, respectively, and the corresponding energy output mode is determined according to the comparison results; S1.3: Energy Reconfiguration: In the uphill deceleration condition, the corresponding reference power is set according to the rated power of the flat slope uniform speed condition. The corresponding pulse duty cycle is obtained according to the dwell time, and the reference power is adjusted. At the same time, the heat reflection guide plates on both sides of the heating wall are deployed, and the injection volume of inert cold mist is determined according to the SBS thermo-oxidative aging index.

[0009] Furthermore, the corresponding SBS thermo-oxidative aging index and temperature drop gradient are extracted, including: S1.1.1: Data Acquisition: Through the vehicle-mounted multi-source sensing system, relevant multi-dimensional data are acquired, including unit operation data, road surface basic data, and real-time material rheological data. The unit operation data includes the unit's travel speed, longitudinal slope angle, and ambient temperature. The road surface basic data includes the three-dimensional elevation model and damage depth of the road surface to be recycled. The real-time material rheological data includes the mixing resistance torque of the mixing chamber and the apparent viscosity of the SBS modified asphalt mixture. S1.1.2: Model Calculation: Based on the overall length of the unit, the road surface to be recycled is divided into multiple road surface units. At the same time, based on the multi-dimensional data, the dynamic heat transfer coefficient and heat retention time corresponding to the road surface unit are determined, and the corresponding SBS thermo-oxidative aging index and temperature drop rate are obtained.

[0010] Furthermore, the minimum length of the road surface unit is greater than three times the length of the entire unit, and each road surface unit can correspond to a complete set of timing actions.

[0011] Furthermore, based on the comparison results of the heat retention time and longitudinal slope angle with preset time threshold ranges and preset slope threshold ranges, respectively, the corresponding energy output mode is determined, specifically as follows: When the longitudinal slope angle is greater than the upper limit of the preset slope threshold range and the thermal residence time is greater than the upper limit of the preset time threshold range, the corresponding operating condition is an uphill deceleration condition, in which case the energy output mode of intermittent pulse, flow guidance, and cold fog is adopted; when the longitudinal slope angle is less than the lower limit of the preset slope threshold range and the thermal residence time is less than the lower limit of the preset time threshold range, the corresponding operating condition is a downhill acceleration condition, in which case the energy output mode of stepped power increase and full filling rate is adopted; conversely, the corresponding operating condition is a flat slope uniform speed condition, in which case the energy output mode of continuous radiation and fine-tuning power is adopted.

[0012] Furthermore, the rotor blade tip linear velocity and cavity filling rate in the optimal parameter set are dynamically adjusted, including: S2.1: Model Solving: Based on the apparent viscosity and SBS thermo-oxidative aging index, a corresponding multi-objective optimization control model is set. Based on the discharge viscosity of the SBS modified asphalt mixture and the aging degree of the SBS modifier, a corresponding objective function is set. At the same time, the corresponding unit speed and old material temperature are determined through multi-dimensional data. Based on the unit speed and old material temperature, the corresponding initial parameter set is obtained. The initial parameter set is verified through the objective function and the multi-objective optimization control model. Based on the verification results, the corresponding optimal parameter set is obtained. S2.2: Dynamic Execution: Based on the working condition category and the optimal parameter set, the execution actions of the mixing host corresponding to the uphill deceleration working condition and the downhill acceleration working condition are adjusted in real time.

[0013] Furthermore, the actions of the mixing unit are adjusted in real time for uphill deceleration and downhill acceleration conditions, including: S2.2.1: Deceleration Control: Based on the optimal parameter set, determine the corresponding optimal rotor tip linear velocity, adjust the current rotor tip linear velocity of the mixing host, switch the return material baffle inside the mixing hopper to the blocking position, and determine the corresponding road elevation difference based on the road surface basic data in the multi-dimensional data, and determine the corresponding processing method based on the comparison result between the road elevation difference and the preset leveling threshold. S2.2.2: Acceleration Control: Adjust the current rotor tip linear velocity and cavity filling rate of the mixing host according to the optimal rotor blade tip linear velocity and optimal cavity filling rate.

[0014] Furthermore, based on the three-dimensional elevation model of the pavement to be recycled, the corresponding reference pavement height is obtained. Then, based on the comparison between the reference pavement height and the depth of damage on the pavement to be recycled, the corresponding pavement elevation difference is obtained. Finally, based on the comparison between the pavement elevation difference and a preset smoothing threshold, the corresponding processing method is determined, specifically: When the elevation difference of the road surface is greater than the preset flatness threshold, the flatness of the corresponding road surface to be recycled is low. At this time, the unfolding angle of the heat reflection guide plates on both sides of the heating wall is increased, the large return material channel is opened at full power, and the blending ratio of the newly added fine aggregate is finely adjusted. Conversely, the flatness of the corresponding road surface to be recycled is high. At this time, the rake drum is controlled to descend, and the lower cold material and the surface hot material are mixed.

[0015] Furthermore, by comparing the discharge temperature and the real-time apparent viscosity of the mixture with preset temperature threshold ranges and preset viscosity threshold ranges, respectively, the corresponding compensation action is determined, specifically as follows: When the discharge temperature is greater than the upper limit of the preset temperature threshold range, the optimal oil-stone ratio target value is determined through the optimal parameter set, and the blending ratio of mineral powder or limestone chips is adjusted according to the optimal oil-stone ratio target value; when the discharge temperature is less than the lower limit of the preset temperature threshold range, the optimal spray pump frequency is determined through the optimal parameter set, and the frequency of the regenerant spray pump is adjusted according to the optimal spray pump frequency; otherwise, the current state is maintained and operation continues. When the real-time apparent viscosity of the mixture is greater than the upper limit of the preset viscosity threshold range, the vibration frequency and amplitude of the mixing host are increased; when the real-time apparent viscosity of the mixture is less than the lower limit of the preset viscosity threshold range, the vibration excitation force of the mixing host is reduced and the static pressure mode is switched; otherwise, the current state is maintained and operation continues.

[0016] An intelligent control system for the process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling uses any one of the above-mentioned intelligent control methods for the process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling.

[0017] Compared with the prior art, the beneficial effects of the present invention are: Firstly, this invention divides the road surface to be recycled into independent road units at least three times the length of the unit. It combines multi-source sensing data to calculate the dynamic heat transfer coefficient and heat retention time of each unit in real time, and matches an automatic switching heating strategy for three working conditions: uphill deceleration, downhill acceleration, and flat slope constant speed. When decelerating uphill, intermittent pulse heating, heat reflection guide plates, and inert cold mist spraying are used. This not only avoids the breakage of SBS molecular chains and cross-linking aging caused by prolonged heating of the road surface, but also blocks oxygen contact and reduces the peak temperature by 5-10°C. When accelerating downhill, stepped power increase and full filling rate heating are used to make up for the temperature drop gap caused by insufficient heating time, thus completely solving the problem of "temperature disorder when speed changes and performance degradation when temperature exceeds the limit" in traditional processes. Secondly, this invention constructs a multi-objective optimization model based on SBS aging kinetics and the viscosity-temperature characteristics of the mixture. First, it combines the unit speed and the temperature of the old material to match the optimal rotor tip linear velocity and cavity filling rate. Then, it dynamically adjusts the rotor speed and switches the return baffle to increase the material stroke when decelerating uphill, so as to avoid strong shearing under high viscosity damaging the SBS polymer network. When accelerating downhill, it increases the rotor speed and reduces the opening of the feed gate in conjunction with microwave heating to ensure the mixing uniformity under short residence time. Thus, it not only avoids the degradation of the modifier caused by excessive shearing, but also solves the problem of "uneven mixing and insufficient temperature" in the traditional fixed parameter mode. Thirdly, this invention forms a closed-loop control through real-time monitoring of the outlet temperature and apparent viscosity. When the temperature is too high, the ratio of mineral powder / limestone chips is automatically adjusted; when the temperature is too low, the frequency of regenerating agent spraying is automatically increased; when the viscosity is too high, the vibration frequency is increased to enhance kneading and compaction; and when the viscosity is too low, the static pressure mode is switched to avoid aggregate breakage. Thus, the temperature fluctuation of the recycled mixture can be controlled within ±3℃, and the viscosity can always fall within the optimal compaction window. This can improve the compaction degree of the recycled pavement, reduce the incidence of early defects such as rutting and cracking, and significantly extend the service life of the pavement. Fourthly, when the flatness is poor, the present invention achieves heat capacity buffering through the adjustment of the guide plate angle, the large return channel, and the fine aggregate fine adjustment, without the need for additional machine stoppage intervention. When the flatness is high, the cold material in the lower layer and the hot material on the surface can be directly mixed by rake and drum to make them naturally balance the temperature, thus eliminating the need for frequent manual parameter adjustments. At the same time, it also reduces the excessive addition of regenerator and the waste of resources such as waste material, which is in line with the development trend of green and low-carbon maintenance. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the process parameter intelligent control method in this invention; Figure 2 This is a schematic diagram of the data mapping process in this invention; Figure 3 This is a schematic diagram of the process for confirming the working condition category in this invention; Figure 4 This is a schematic flowchart of the synergistic adjustment method for compound mixing and adaptation in this invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] refer to Figure 1 This embodiment provides an intelligent control method for the process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling process. The intelligent control method for process parameters specifically includes the following steps: Step S1: Spatiotemporal Mapping Reconstruction and Temperature Control. This involves using an onboard multi-source sensing system to collect real-time multi-dimensional data, including unit operation data (i.e., travel speed, longitudinal slope angle, and ambient temperature), road surface basic data (i.e., the three-dimensional morphology data of the road surface to be recycled and the depth distribution of defects), and real-time material rheological data (i.e., the mixing torque of the mixing unit and the compactability of the material). Simultaneously, using a 100-meter-level unit spatial distribution model, the road surface to be recycled is divided into multiple road surface units. Based on the collected multi-dimensional data, the dynamic heat transfer coefficient and heat retention time of each road surface unit in the entire process of heating, loosening, and remixing are determined. The determined dynamic heat transfer coefficient and heat retention time are then combined with the collected multi-dimensional data to adjust the energy output mode of the heating machine.

[0021] Step S2: Coordinated Adjustment of Compound Mixing. This involves constructing a multi-objective optimization control model based on the aging kinetics of SBS modifier and the viscosity-temperature characteristics of the mixture. The optimal parameter set for the compound mixing host is then obtained through a set objective function. Simultaneously, based on the thermal residence time determined in Step S1, the rotor tip linear velocity and cavity filling rate of the compound mixing host are dynamically adjusted within the obtained optimal parameter set.

[0022] Step S3: Real-time compensation of gradation heat capacity. This involves using an infrared thermometer and viscosity monitoring module (i.e., a "power-viscosity" lookup table set up at the discharge port of the mixing host; this table can be customized according to actual needs, so it is not specifically described in this embodiment) to obtain the corresponding apparent viscosity value by reading the three-phase current and speed encoder data of the mixing host drive motor. The corresponding discharge temperature and real-time apparent viscosity of the mixture are then collected. Simultaneously, the collected discharge temperature and real-time apparent viscosity of the mixture are compared with preset temperature threshold ranges and preset viscosity threshold ranges, respectively. Based on the comparison results, the corresponding compensation action is determined. Specifically: When the collected discharge temperature exceeds the upper limit of the preset temperature threshold range, the optimal oil-aggregate ratio target value is determined based on the optimal parameter set obtained in step S2, and the blending ratio of mineral powder or limestone chips is increased (e.g., by 0.5%-1.5%) according to the determined optimal oil-aggregate ratio target value. When the collected discharge temperature is below the lower limit of the preset temperature threshold range, the optimal spray pump frequency is determined based on the optimal parameter set obtained in step S2, and the current frequency of the regenerant spray pump is adjusted (e.g., by 3%-8%) according to the determined optimal spray pump frequency. Conversely, when the collected discharge temperature is within the preset temperature threshold range, the current state is maintained and operation continues.

[0023] When the real-time apparent viscosity of the mixture is greater than the upper limit of the preset viscosity threshold range, the vibration frequency and amplitude of the mixing unit are increased to enhance the kneading effect and force the SBS modified asphalt mixture particles to interlock and compact. When the real-time apparent viscosity of the mixture is less than the lower limit of the preset viscosity threshold range, the vibration excitation force of the mixing unit is reduced, and the system switches to static pressure mode to prevent the aggregate from being crushed or developing wavy patterns. Conversely, when the real-time apparent viscosity of the mixture is within the preset viscosity threshold range, the system continues to operate in the current state.

[0024] This embodiment also provides an intelligent control system for the process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling, which uses the above-mentioned intelligent control method for the process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling.

[0025] In this embodiment, by collecting multi-dimensional data, the dynamic heat transfer coefficient and heat retention time corresponding to each pavement unit at the site to be recycled are determined. Based on the determined dynamic heat transfer coefficient and heat retention time, the energy output mode of the heater is adjusted. (Reference) Figure 2 and Figure 3 This embodiment provides a method for reconstructing temperature control based on spatiotemporal mapping, which specifically includes the following steps: Step S1.1: Data Mapping. This involves using an onboard multi-source sensing system to collect relevant multi-dimensional data in real time. Based on this data, the dynamic heat transfer coefficient and heat retention time of each pavement unit in the area to be recycled are determined, and the corresponding SBS thermo-oxidative aging index and temperature drop gradient are extracted. Details are as follows: Step S1.1.1: Data Acquisition. This involves acquiring multi-dimensional data in real time through the onboard multi-source sensing system, including unit operation data, road surface data, and real-time material rheological data. Specifically, the unit's driving axle wheel speed sensors and GPS locator acquire the corresponding travel speed; the dual-axis tilt sensors mounted on the fuselage acquire the corresponding longitudinal slope angle; and the temperature sensor at the front of the heater acquires the corresponding ambient temperature. In other words, the unit's operating data is obtained by acquiring the travel speed, longitudinal slope angle, and ambient temperature.

[0026] Furthermore, a vehicle-mounted LiDAR scanner is used to scan the three-dimensional topography of the pavement to be recycled, identifying the location and depth of ruts, potholes, and other defects. Based on the identified locations and depths, a three-dimensional elevation model of the pavement is constructed. A three-dimensional ground-penetrating device (such as a vehicle-mounted ground-penetrating radar) is then used to continuously scan the direction of travel, using the time difference of electromagnetic wave reflection between the asphalt layer and the base course to obtain the corresponding defect depth. In other words, the corresponding pavement foundation data is obtained by acquiring the three-dimensional elevation model and defect depth.

[0027] Furthermore, based on the three-phase current of the mixing host drive motor and the encoder speed, the corresponding mixing resistance torque within the mixing chamber is determined. Simultaneously, based on the rheological properties of road asphalt, the SBS modified asphalt mixture is treated as a power-law fluid, and the corresponding apparent viscosity is determined using the power-law fluid constitutive equation. In this embodiment, the formulas for obtaining the mixing resistance torque and apparent viscosity are as follows:

[0028] in: The torque representing the stirring resistance generated by the material in the mixing chamber. The torque constant of the main mixing motor is... This refers to the real-time operating current of the stator of the main mixing motor. This is the equivalent moment of inertia between the mixing rotor and the motor shaft. The angular velocity of the mixing rotor is... The time rate of change of the rotor angular velocity. The real-time apparent viscosity of SBS modified asphalt mixture. This is the consistency coefficient. For power-law fluid rheological index. This is the rotational speed of the mixing rotor.

[0029] In other words, by determining the stirring resistance torque and apparent viscosity, the corresponding real-time rheological data of the material can be obtained.

[0030] Step S1.1.2: Model Calculation. This involves setting the origin point based on the unit's current position. Specifically, the unit's current position is set as the origin, and the direction of travel is divided according to the unit's overall length to obtain multiple road surface units. Specifically, the length range of each road surface unit is set based on the unit's overall length, with the minimum length of each unit being greater than three times the unit's overall length. This ensures that each road surface unit corresponds to a complete sequence of actions: "heating → loosening → remixing." For example, if the unit's overall length is 30m, the length of each road surface unit is set to 100m.

[0031] Furthermore, by applying a modified Newton's law of cooling, the convective heat transfer coefficient, thermal radiation coefficient, and thermal conductivity coefficient corresponding to the road surface unit are obtained. These coefficients are then combined to determine the dynamic heat transfer coefficient corresponding to the road surface unit. Specifically:

[0032] in: The dynamic heat transfer coefficient, The convective heat transfer coefficient is... The thermal emissivity, The thermal conductivity coefficient, This refers to the real-time travel speed of the generator set. To heat the absolute temperature of the wall surface, The absolute temperature of the road surface. It is the Stefan-Boltzmann constant. The infrared emissivity of SBS modified asphalt pavement, The thermal conductivity of the asphalt mixture. For effective heat transfer thickness.

[0033] Furthermore, the effective action time for the heating process is determined by the ratio between the effective heating length of the heating wall and the real-time travel speed of the unit. The effective action time for the loosening process is determined by the ratio between the number of cuts required by the loosening machine and the speed of the loosening machine. The effective volume of the mixing chamber and the filling rate of the mixing chamber (usually set to 0.4-0.7) are combined to obtain the real-time effective volume of the mixture within the mixing chamber. The effective action time for the mixing process is then determined by the ratio between the real-time effective volume of the mixture within the mixing chamber and the feeding rate of the mixing chamber.

[0034] Furthermore, based on the effective action time determined for each process, the corresponding operating section length for each process is determined, including the operating section lengths for the heating process, the loosening process, and the remixing process. Simultaneously, the determined operating section lengths for the heating process, the loosening process, and the remixing process are combined, and the corresponding heat retention time is determined based on the real-time travel speed of the unit. Specifically:

[0035] in: For thermal residence time, The length of the heating process section. This refers to the length of the working section in the loosening process. This refers to the length of the remixing process section. For device response delay time, The effective operating time of the heating process. The effective working time of the loosening process, This refers to the effective action time of the remixing process. This represents the real-time travel speed of the generator set.

[0036] Furthermore, by determining the heat retention time and dynamic heat transfer coefficient, the formulas for obtaining the corresponding SBS thermo-oxidative aging index and temperature drop rate are obtained, specifically as follows:

[0037] in: The SBS thermo-oxidative aging index, The aging reaction rate constant is 1.2 * 10⁻⁶ (the aging reaction rate constant for SBS modified asphalt is 1.2 * 10⁻⁶). 10 s -1 ), The activation energy for SBS oxidation is 85 kJ / mol. This is the gas constant (valued at 8.314 J / (mol·K)). Let τ be the temperature of the road surface element at time τ. Let τ be the oxygen concentration of the pavement element at time τ. For the rate of temperature drop, The dynamic heat transfer coefficient, The surface area of ​​the road surface unit. The instantaneous temperature of the road surface unit. For ambient temperature, For the volume of the road surface unit, Specific heat capacity (valued at 920 J / (kg·K)). The density of SBS modified asphalt mixture. This refers to the thermal residence time.

[0038] Step S1.2: Operating Condition Processing. Based on the longitudinal slope angle acquired in Step S1.1.1 and the heat retention time determined in Step S1.1.2, the acquired longitudinal slope angle is compared with a preset slope threshold range (e.g., -3 to 3°), and the determined heat retention time is compared with a preset time threshold range (e.g., 8 to 12 seconds). Based on the comparison results, the corresponding energy output mode is determined. Specifically: When the acquired longitudinal slope angle is greater than the upper limit of the preset slope threshold range (i.e., 3°) and the determined heat residence time is greater than the upper limit of the preset time threshold range (i.e., 12s), the corresponding operating condition is an uphill deceleration condition, in which case the energy output mode of intermittent pulse, diversion, and cold fog is adopted. When the acquired longitudinal slope angle is less than the lower limit of the preset slope threshold range (i.e., -3°) and the determined heat residence time is less than the lower limit of the preset time threshold range (i.e., 8s), the corresponding operating condition is a downhill acceleration condition, in which case the energy output mode of stepped power increase and full filling rate is adopted. Conversely, the corresponding operating condition is a flat slope uniform speed condition, in which case the energy output mode of continuous radiation and fine-tuning power is adopted.

[0039] Step S1.3: Energy Reconfiguration. Based on the uphill deceleration condition determined in Step S1.2, a corresponding reference power is set according to the rated power of the flat-slope constant-speed condition. The corresponding pulse duty cycle is obtained using the thermal residence time determined in Step S1.1.2, and the set reference power is adjusted based on the obtained pulse duty cycle. Simultaneously, the heat-reflecting guide plates on both sides of the heating wall are deployed to guide excess heat energy during the heating process to the lower layers. Specifically, the deployment angle of the heat-reflecting guide plates is determined based on the rut depth of the unit. The formulas for obtaining the pulse duty cycle and the deployment angle of the heat-reflecting guide plates in this embodiment (note that only data calculation is performed here, and the unit conversion of related data can be done according to the relevant coefficient unit conversion, which is not specifically explained here) are as follows:

[0040] in: The pulse duty cycle. The deployment angle of the heat-reflecting guide plate. The depth of the ruts of the generator set. This refers to the thermal residence time.

[0041] Furthermore, based on the SBS thermo-oxidative aging index determined in step S1.1.2, the corresponding injection volume of inert cold fog (i.e., generated by ultrasonic atomization of liquid nitrogen or carbon dioxide) is determined to block the contact between the road surface and oxygen on the road to be recycled, thereby inhibiting heat accumulation and reducing the peak road surface temperature by 5-10℃. Specifically, the formula for obtaining the inert cold fog injection volume in this embodiment (it is worth noting that only data calculation is performed here, and the unit conversion of the relevant data can be performed according to the relevant coefficient unit conversion, which is not specifically explained here) is as follows:

[0042] in: This refers to the amount of inert cold mist sprayed. The SBS thermo-oxidative aging index.

[0043] In this embodiment, the optimal parameter set corresponding to the mixing host is determined by constructing a multi-objective optimization control model and setting an objective function. Then, the rotor tip linear velocity and cavity filling rate of the mixing host are dynamically adjusted using the thermal residence time determined in step S1.1.2. (Reference) Figure 4 This embodiment provides a synergistic adjustment method for compound mixing and adaptation, which specifically includes the following steps: Step S2.1: Model Solving. Based on the apparent viscosity obtained in Step S1.1.1 and the SBS thermo-oxidative aging index determined in Step S1.1.2, a corresponding multi-objective optimization control model is set. In other words, the corresponding multi-objective optimization control model is constructed by obtaining the maximum apparent viscosity and the minimum SBS thermo-oxidative aging index. Simultaneously, a corresponding objective function is set based on the discharge viscosity of the SBS modified asphalt mixture and the aging degree of the SBS modifier. That is, the corresponding objective function is constructed by setting the compaction window of the SBS modified asphalt mixture discharge viscosity to within the optimal compaction window and setting the aging degree of the SBS modifier to the minimum. (It is worth noting that the objective function and multi-objective optimization control model in this embodiment are conventional model construction methods, therefore, they are not specifically described in this embodiment.) Furthermore, based on the multi-dimensional data obtained in step S1.1.1, the corresponding unit speed and old material temperature are determined. Using the determined unit speed and old material temperature, the corresponding rotor tip linear velocity and cavity filling rate are determined from a preset "Operating Condition-Parameter Comparison Master Table" (which can be specifically set according to actual needs, therefore not specifically described in this embodiment, and is only illustrative in this embodiment). Simultaneously, the determined rotor tip linear velocity and cavity filling rate are verified through the constructed objective function and multi-objective optimization control model to obtain the corresponding optimal parameter set.

[0044] During the specific implementation process, the "Working Condition-Parameter Comparison Master Table" is shown in Table 1 below: Table 1: Operating Condition-Parameter Comparison Master Table

[0045] Specifically, when the unit speed is 3 m / s and the raw material temperature is 140℃, the current operating condition is within the transition range between operating condition B and operating condition C in the "Operating Condition-Parameter Comparison Master Table". At this time, based on the recommended rotor tip linear velocity and recommended cavity filling rate corresponding to operating conditions B and C respectively, a linear interpolation algorithm is used to obtain the corresponding optimal rotor tip linear velocity (e.g., 28 m / s) and optimal cavity filling rate (e.g., 65%). Simultaneously, the obtained optimal rotor tip linear velocity and optimal cavity filling rate are verified using the constructed objective function and multi-objective optimization control model. If all verifications pass, then the corresponding optimal parameter set is 28 m / s and 65%. It is worth noting that the "Operating Condition-Parameter Comparison Master Table" here only provides a portion of the parameters and does not elaborate on all of them; it is only for illustrative purposes.

[0046] Step S2.2: Dynamic Execution. Based on the operating condition categories determined in Step S1.2, including uphill deceleration, downhill acceleration, and flat-slope constant-speed conditions, and using the optimal parameter set obtained in Step S2.1, the execution actions of the mixing unit corresponding to the uphill deceleration and downhill acceleration conditions are adjusted in real time. Specifically: Step S2.2.1: Deceleration Control. Based on the optimal parameter set obtained in Step S2.1, the corresponding optimal rotor tip linear velocity is determined. The current rotor tip linear velocity of the mixing unit is adjusted to reach the optimal rotor tip linear velocity to prevent SBS molecular chain breakage due to strong shear under high viscosity. Simultaneously, the return material baffle inside the mixing bin of the mixing unit is switched from the "straight-through position" to the "blocking position" to increase the travel distance of the SBS modified asphalt mixture within the mixing bin. This allows the returned material to carry away the generated heat, thereby preventing localized overheating.

[0047] Furthermore, based on the multi-dimensional data obtained in step S1.1.1, the corresponding pavement base data is determined, namely the three-dimensional elevation model and damage depth of the pavement to be regenerated. That is, through the three-dimensional elevation model of the pavement to be regenerated, the reference pavement height is obtained, and the obtained reference pavement height is compared with the damage depth of the pavement to be regenerated to obtain the corresponding pavement elevation difference. Simultaneously, the obtained pavement elevation difference is compared with a preset smoothing threshold (which can be specifically set according to actual needs, and therefore is not specifically described in this embodiment), and based on the comparison result, the corresponding processing method is determined, specifically as follows: When the obtained road surface elevation difference is greater than the preset smoothness threshold, the corresponding road surface to be recycled has low smoothness. At this time, the deployment angle of the heat reflective guide plates on both sides of the heating wall will be increased to forcibly introduce the heat originally accumulated on the road surface into the middle and lower layers, thereby avoiding the thermal-oxidative aging phenomenon of SBS modified asphalt mixture at the road surface stage. At the same time, the large return material channel is opened at full power to ensure that the return material baffle inside the mixing bin is in the maximum blocking position, so that the hot material can be repeatedly tumbled and crushed inside the mixing bin, and then more heat can be carried away by air convection. At the same time, the blending ratio of the newly added fine aggregate (i.e., mineral powder / limestone chips) is finely adjusted (it can be adjusted according to actual needs, so it is not specifically described in this embodiment), so as to absorb the excess heat generated by the upper superheated material by increasing the proportion of fine aggregate without changing the asphalt-aggregate ratio, thereby stabilizing the temperature at about 145℃ through the heat capacity buffering effect.

[0048] When the obtained road surface elevation difference is not greater than the preset smoothing threshold, the corresponding road surface to be recycled has high smoothness. At this time, the rake drum can be lowered by controlling the hydraulic system so that the rake drum blades cut into the lower layer (about 5-8cm), and the lower layer of cold material (its temperature is usually 50-80℃) is turned over, so that the lower layer of cold material and the surface hot material (its temperature is above 160℃) can be mixed inside the mixing bin. In other words, through the mixing between cold and hot materials, the overall temperature will drop to about 145℃, so that there is no need to turn on the microwave or cold mist for additional intervention.

[0049] Step S2.2.2: Acceleration and Control. Based on the optimal parameter set obtained in Step S2.1, the corresponding optimal rotor tip linear velocity is determined. The current rotor tip linear velocity of the mixing unit is adjusted to reach the optimal rotor tip linear velocity to prevent SBS molecular chain degradation caused by high temperature and high shear. Simultaneously, the jacketed microwave module of the mixing chamber is activated to allow microwaves to penetrate the SBS modified asphalt mixture and directly act on the aggregates and asphalt molecules, thereby generating volumetric heating.

[0050] Furthermore, based on the optimal parameter set obtained in step S2.1, the corresponding optimal cavity filling rate is determined. Based on this determined optimal cavity filling rate, the opening of the feed hopper door of the mixing unit is adjusted by pulling the baffle plate of the feed hopper door via a hydraulic push rod, thereby reducing the opening of the feed hopper door. In other words, the current cavity filling rate within the mixing hopper of the mixing unit is adjusted based on the determined optimal cavity filling rate. Specifically, by adjusting (i.e., reducing) the opening of the feed hopper door, the amount of material fed in decreases, the material level within the mixing hopper drops, and each aggregate in the SBS modified asphalt mixture within the mixing hopper can come into contact with the heated cavity wall and microwave field, thus maximizing the heated area.

[0051] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended embodiments and their equivalents.

Claims

1. A method for intelligent control of process parameters in in-situ hot recycling of SBS modified asphalt pavement, characterized in that, Including: S1: Spatiotemporal mapping reconstruction temperature control: Through the vehicle-mounted multi-source sensing system, relevant multi-dimensional data is collected and acquired. At the same time, the road surface to be regenerated is divided into multiple road surface units. Through the multi-dimensional data, the dynamic heat transfer coefficient and heat retention time corresponding to the road surface unit are determined. Based on the dynamic heat transfer coefficient and heat retention time, the energy output mode of the heater is adjusted. S2: Coordinated adjustment of compound mixing adaptation: By constructing a multi-objective optimization control model and objective function, the optimal parameter set corresponding to the compound mixing host is obtained, and the rotor tip linear velocity and cavity filling rate in the optimal parameter set are dynamically adjusted according to the thermal residence time. S3: Real-time compensation of gradation heat capacity: Collect the discharge temperature and real-time apparent viscosity of the mixture from the discharge port of the mixing host, and determine the corresponding compensation action by comparing the results with the preset temperature threshold range and preset viscosity threshold range.

2. The intelligent control method for process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling according to claim 1, characterized in that, Adjusting the energy output mode of the heater includes: S1.1: Data Mapping: Through the vehicle-mounted multi-source perception system, relevant multi-dimensional data are collected in real time. At the same time, based on the multi-dimensional data, the dynamic heat transfer coefficient and heat retention time of the road unit are determined, and the corresponding SBS thermo-oxidative aging index and temperature drop gradient are extracted. S1.2: Operating condition processing: The thermal retention time and the longitudinal slope angle in the multi-dimensional data are compared with the preset time threshold range and the preset slope threshold range, respectively, and the corresponding energy output mode is determined according to the comparison results; S1.3: Energy Reconfiguration: In the uphill deceleration condition, the corresponding reference power is set according to the rated power of the flat slope uniform speed condition. The corresponding pulse duty cycle is obtained according to the dwell time, and the reference power is adjusted. At the same time, the heat reflection guide plates on both sides of the heating wall are deployed, and the injection volume of inert cold mist is determined according to the SBS thermo-oxidative aging index.

3. The intelligent control method for process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling process according to claim 2, characterized in that, Extract the corresponding SBS thermo-oxidative aging index and temperature drop gradient, including: S1.1.1: Data Acquisition: Through the vehicle-mounted multi-source sensing system, relevant multi-dimensional data are acquired, including unit operation data, road surface basic data, and real-time material rheological data. The unit operation data includes the unit's travel speed, longitudinal slope angle, and ambient temperature. The road surface basic data includes the three-dimensional elevation model and damage depth of the road surface to be recycled. The real-time material rheological data includes the mixing resistance torque of the mixing chamber and the apparent viscosity of the SBS modified asphalt mixture. S1.1.2: Model Calculation: Based on the overall length of the unit, the road surface to be recycled is divided into multiple road surface units. At the same time, based on the multi-dimensional data, the dynamic heat transfer coefficient and heat retention time corresponding to the road surface unit are determined, and the corresponding SBS thermo-oxidative aging index and temperature drop rate are obtained.

4. The intelligent control method for process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling process according to claim 3, characterized in that, The minimum length of the road surface unit is more than three times the length of the entire unit, and each road surface unit can correspond to a complete set of timing actions.

5. The intelligent control method for process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling according to claim 2, characterized in that, Based on the comparison results of the heat retention time and longitudinal slope angle with the preset time threshold range and preset slope threshold range, respectively, the corresponding energy output mode is determined, specifically: When the longitudinal slope angle is greater than the upper limit of the preset slope threshold range and the thermal residence time is greater than the upper limit of the preset time threshold range, the corresponding operating condition is an uphill deceleration condition, in which case the energy output mode of intermittent pulse, flow guidance, and cold fog is adopted; when the longitudinal slope angle is less than the lower limit of the preset slope threshold range and the thermal residence time is less than the lower limit of the preset time threshold range, the corresponding operating condition is a downhill acceleration condition, in which case the energy output mode of stepped power increase and full filling rate is adopted; conversely, the corresponding operating condition is a flat slope uniform speed condition, in which case the energy output mode of continuous radiation and fine-tuning power is adopted.

6. The intelligent control method for process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling according to claim 1, characterized in that, Dynamic adjustment of the rotor blade tip linear velocity and cavity filling rate in the optimal parameter set includes: S2.1: Model Solving: Based on the apparent viscosity and SBS thermo-oxidative aging index, a corresponding multi-objective optimization control model is set. Based on the discharge viscosity of the SBS modified asphalt mixture and the aging degree of the SBS modifier, a corresponding objective function is set. At the same time, the corresponding unit speed and old material temperature are determined through multi-dimensional data. Based on the unit speed and old material temperature, the corresponding initial parameter set is obtained. The initial parameter set is verified through the objective function and the multi-objective optimization control model. Based on the verification results, the corresponding optimal parameter set is obtained. S2.2: Dynamic Execution: Based on the working condition category and the optimal parameter set, the execution actions of the mixing host corresponding to the uphill deceleration working condition and the downhill acceleration working condition are adjusted in real time.

7. The intelligent control method for process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling process according to claim 6, characterized in that, The actions of the mixing unit are adjusted in real time for uphill deceleration and downhill acceleration conditions, including: S2.2.1: Deceleration Control: Based on the optimal parameter set, determine the corresponding optimal rotor tip linear velocity, adjust the current rotor tip linear velocity of the mixing host, switch the return material baffle inside the mixing hopper to the blocking position, and determine the corresponding road elevation difference based on the road surface basic data in the multi-dimensional data, and determine the corresponding processing method based on the comparison result between the road elevation difference and the preset leveling threshold. S2.2.2: Acceleration Control: Adjust the current rotor tip linear velocity and cavity filling rate of the mixing host according to the optimal rotor blade tip linear velocity and optimal cavity filling rate.

8. The intelligent control method for process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling according to claim 7, characterized in that, Based on the three-dimensional elevation model of the pavement to be recycled, the corresponding reference pavement height is obtained. Then, based on the comparison between the reference pavement height and the depth of damage on the pavement to be recycled, the corresponding pavement elevation difference is obtained. Finally, based on the comparison between the pavement elevation difference and a preset smoothing threshold, the corresponding processing method is determined, specifically: When the elevation difference of the road surface is greater than the preset flatness threshold, the flatness of the corresponding road surface to be recycled is low. At this time, the unfolding angle of the heat reflection guide plates on both sides of the heating wall is increased, the large return material channel is opened at full power, and the blending ratio of the newly added fine aggregate is finely adjusted. Conversely, the flatness of the corresponding road surface to be recycled is high. At this time, the rake drum is controlled to descend, and the lower cold material and the surface hot material are mixed.

9. The intelligent control method for process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling according to claim 1, characterized in that, By comparing the discharge temperature and the real-time apparent viscosity of the mixture with preset temperature threshold ranges and preset viscosity threshold ranges, respectively, the corresponding compensation action is determined, specifically as follows: When the discharge temperature is greater than the upper limit of the preset temperature threshold range, the optimal oil-stone ratio target value is determined through the optimal parameter set, and the blending ratio of mineral powder or limestone chips is adjusted according to the optimal oil-stone ratio target value; when the discharge temperature is less than the lower limit of the preset temperature threshold range, the optimal spray pump frequency is determined through the optimal parameter set, and the frequency of the regenerant spray pump is adjusted according to the optimal spray pump frequency; otherwise, the current state is maintained and operation continues. When the real-time apparent viscosity of the mixture is greater than the upper limit of the preset viscosity threshold range, the vibration frequency and amplitude of the mixing host are increased; when the real-time apparent viscosity of the mixture is less than the lower limit of the preset viscosity threshold range, the vibration excitation force of the mixing host is reduced and the static pressure mode is switched; otherwise, the current state is maintained and operation continues.

10. An intelligent control system for the process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling, characterized in that, The method for intelligent control of process parameters of SBS modified asphalt pavement remixing and in-situ hot recycling as described in any one of claims 1-9 is used.

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