An evaluation method and device for asphalt mixture carbon emission behavior and attenuation law

Abstract

The application provides a hot-mixed asphalt mixture carbon emission behavior and attenuation law evaluation device and method, which comprises the following steps: construction and pre-operation of a test environment; preparation and storage of asphalt mixture; preparation of carbon emission test; reading and collection of test data; drawing of a correlation diagram of different carbon emission data, test time and environmental temperature based on the obtained data; calculation of a baseline emission difference number envelope area and evaluation index; and determination of carbon emission behavior and attenuation law. The application is suitable for carbon emission behavior evaluation of different types of hot-mixed or warm-mixed asphalt mixtures in road engineering, can accurately evaluate and estimate the carbon emission amount and attenuation law of the asphalt mixture after mixing, can serve as an effective basis for carbon emission evaluation, can effectively improve the carbon emission accounting accuracy of road engineering construction, and thus provides relevant basis for effective control of carbon emission of road engineering construction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon emission accounting of road construction engineering, and particularly relates to a hot-mixed asphalt mixture carbon emission behavior and attenuation law evaluation device and apparatus. BACKGROUND

[0002] With the increasing global greenhouse gas emissions, problems such as glacier melting and frequent extreme weather have attracted close attention of countries around the world. The highway transportation industry is a "heavy disaster area" of greenhouse gas emissions. Therefore, it is imminent to explore energy saving and emission reduction in highway engineering.

[0003] Asphalt mixture is often used as the surface layer material of asphalt pavement due to its good road performance and mature construction technology, but a large amount of greenhouse gases will be generated in its production, transportation and construction process. The production and transportation of hot-mixed asphalt mixture are at a high temperature (usually not less than 135℃), which will lead to a large amount of energy consumption and high greenhouse gas emissions, and have many adverse effects on the environment. The mixing temperature of warm-mixed asphalt mixture is reduced by more than 30~40℃, but the manufacturing temperature of warm-mixed asphalt mixture still needs to be between 100~130℃, which means that warm-mixed asphalt mixture still produces a large amount of greenhouse gases.

[0004] Existing researches mainly focus on reducing carbon emissions in pavement construction through technical measures, but ignore the carbon emissions generated by different types of asphalt mixtures themselves in high temperature environment, and lack an index system and method for accurately evaluating the emission behavior and characteristics of asphalt mixture. SUMMARY

[0005] The present application aims to provide an asphalt mixture carbon emission behavior and attenuation law evaluation scheme to solve the problems in the prior art. The scheme is suitable for carbon emission behavior evaluation of different types of hot-mixed or warm-mixed asphalt mixtures in road engineering, can accurately evaluate and predict the carbon emissions and attenuation law of asphalt mixture after mixing, and can be used as an effective basis for carbon emission evaluation, thereby improving the accuracy of carbon emission accounting in road engineering construction.

[0006] To achieve the above purpose, the present application provides a hot-mixed asphalt mixture carbon emission behavior and attenuation law evaluation method, which comprises the following steps:

[0007] S1, construction and pre-operation of the test environment, installation of the sealed box, and test of the air tightness, heat preservation and accuracy of the sensor of the sealed box;

[0008] S2, preparation and storage of asphalt mixture, mix the asphalt mixture according to the specification, and store the prepared asphalt mixture in a constant temperature oven at a preset temperature for a preset time to ensure the constant temperature of the asphalt mixture;

[0009] S3, carbon emission test preparation, place the sealed box in the constant temperature oven, and fill the mixed asphalt mixture into the bottom of the sealed box in multiple times, and use a tamper to insert and tamp after each filling to ensure that there is no gap in the asphalt mixture, and close the sealed box after filling;

[0010] S4, reading and collecting test data, place the sealed test box for a period of time, and start recording carbon emission data after the sensor temperature stabilizes, divide the internal space of the test box into multiple height regions, use the height h at the center position as the space geometric calibration parameter, and obtain the carbon emission data based on the data at the calibration position, the obtained data includes gas concentration P, environment temperature t and test time T;

[0011] S5, based on the obtained data, draw a correlation diagram of different carbon emission data and test time and environment temperature, calculate the baseline emission difference envelope area and evaluation index, and determine the carbon emission behavior and decay law.

[0012] Further, in S1, the sealed box is placed in the laboratory ventilation to ensure that there is no obstruction within a certain space range around the box; gas sensors, temperature sensors and corresponding reading devices are installed inside the sealed box; the upper cover of the sealed box is closed, a certain amount of CO2 is filled through the inflation hole of the upper cover, and then the inflation hole is closed; after the CO2 concentration reading data is stable, the initial data is recorded, and the CO2 concentration is recorded again after a period of time, and the concentration data difference is less than 0.5% to confirm the airtightness of the sealed box; the test accuracy of the temperature sensor and the heat preservation of the sealed box are detected by heat preservation of the sealed box.

[0013] Further, in S2, the mixing temperature of the asphalt mixture is 150-170℃, and the mixing time is controlled in the range of 90-120s; the prepared asphalt mixture is placed in a constant temperature oven with a temperature range of 150-170℃ for 5-10min.

[0014] Further, in S3, the sealed box is placed in the constant temperature oven for heat preservation, and the mixing of the asphalt mixture is synchronized; the mixed asphalt mixture is filled into the bottom of the sealed box in 3-5 times.

[0015] Further, in S4, the sealed box is left for 5-10 minutes, and after the sensor temperature is stable, the carbon emission data recording is started; the test time T is determined according to the temperature change range of the asphalt mixture, the temperature change range of the asphalt mixture is 90-160℃, and the test time is the time experienced by the asphalt mixture temperature from 160℃ to 90℃; within the time range, the gas concentration and environmental temperature data of different test positions are recorded every 5-10 minutes; when the lower limit of the test temperature is reached, the final data is recorded, and the recorded data is arranged and the subsequent carbon emission behavior evaluation is carried out; each group of carbon emission tests is carried out for multiple parallel tests, and the test data is summarized and arranged.

[0016] Further, in S5, the carbon emission data and test time correlation graph takes the test time T as the independent variable X and the gas concentration P as the dependent variable Y, and an X-Y line graph is drawn, and n correlation curves are drawn in the same coordinate system, each curve corresponding to the test height standard value h n ; the carbon emission data and environmental temperature correlation graph takes the test height standard value environmental temperature t as the independent variable X and the gas concentration P as the dependent variable Y, and an X-Y line graph is drawn, and n correlation curves are drawn in the independent coordinate system, each curve in the independent coordinate system corresponding to the test height standard value h n .

[0017] Further, in S5, the reference emission difference number envelope area S T-h of the carbon emission data and test time T is calculated, based on the carbon emission data and test time T relationship line graph in the same coordinate system, for each test height standard value h corresponding to the line, taking the test starting point as the first reference point, drawing a first reference line parallel to the X axis, and then taking the test endpoint as the second reference point, drawing a second reference line perpendicular to the first reference line, the area of the figure enclosed by the first reference line, the second reference line and the related relationship line is the reference emission difference number envelope area S T-h under the condition of the corresponding test height standard value h;

[0018] The reference emission difference number envelope area S t-h of the carbon emission data and environmental temperature is calculated, based on the carbon emission data and environmental temperature t relationship line graph in the independent coordinate system, for each test time T corresponding to the line, taking the test starting point as the first reference point, drawing a first reference line parallel to the X axis, and then taking the test endpoint as the second reference point, drawing a second reference line perpendicular to the first reference line, the area of the figure enclosed by the first reference line, the second reference line and the related relationship line is the reference emission difference number envelope area S t-h under the condition of the corresponding test height standard value h.

[0019] Further, the reference emission difference number envelope area ST-h The specific calculation method is that the linear regression of the relationship between the carbon emission data and the test time T is carried out, the regression curve and the regression formula with a correlation coefficient greater than 0.96 are obtained, and the definite integral value S is obtained by carrying out the definite integral calculation of the regression formula in the interval [0, T] d Then, the definite integral value S d is subtracted from the test starting point ordinate Y q , and the product of the test total time T is obtained to obtain the reference emission difference number envelope area S T-h .

[0020] Further, the evaluation indexes of the carbon emission behavior and the attenuation law include the reference emission difference number envelope area S h , the envelope area standard value S o , the deviation degree W, the maximum diffusion rate K and the limit diffusion concentration P max ; the meanings and calculation methods are as follows:

[0021] S o = (S h1 +S h2 +S h3 +…+ S hn ) / n, wherein n is the number of test height partitions;

[0022] W=Max{|S hi -S o |}, i=1, 2, 3, 4, …, n;

[0023] P max is the maximum diffusion concentration value of the emission gas.

[0024] The application also provides a hot-mixed asphalt mixture carbon emission behavior and attenuation law evaluation device, which adopts the hot-mixed asphalt mixture carbon emission behavior and attenuation law evaluation device as described above, and comprises a sealing box made of organic glass, a temperature insulation layer is arranged on the outer surface of the sealing box, the sealing box is provided with an upper cover capable of being opened or closed, the upper cover is provided with an inflation hole for inflating the inside, and a gas sensor, a temperature sensor, a gas reading device and a temperature reading device are installed in the sealing box, the gas sensor adopts a sensor capable of detecting CO x and NO x , the temperature sensor adopts a sensor of a thermistor, and the gas reading device and the temperature reading device are respectively used for reading the temperature of the gas sensor and the temperature sensor.

[0025] The gas sensor and the temperature sensor are provided in multiple groups and are connected to different height positions in the sealing box through sensor connecting rods, so as to obtain the data at each height h in the sealing box.

[0026] The above-mentioned scheme of the present application has the following beneficial effects:

[0027] The hot-mixed asphalt mixture carbon emission behavior and attenuation law evaluation scheme provided by the present application is suitable for carbon emission behavior evaluation of different types of hot-mixed or warm-mixed asphalt mixtures in road engineering, can realize accurate evaluation and estimation of the carbon emission amount and attenuation law of the asphalt mixture after mixing, can also serve as an effective basis for carbon emission evaluation, can effectively improve the carbon emission accounting accuracy of road engineering construction, and thus provides relevant basis for effective control of carbon emission of road engineering construction.

[0028] Other beneficial effects of the present application will be described in detail in the subsequent specific embodiment part. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The present application is a method flow chart;

[0030] Figure 2 The present application is a device schematic diagram;

[0031] Figure 3 The present application is an emission gas and test time relationship curve diagram;

[0032] Figure 4 The present application is an emission gas and test temperature relationship curve diagram;

[0033] Figure 5 The present application is an emission gas and test time relationship curve baseline emission difference number envelope area schematic diagram;

[0034] Figure 6 The present application is an emission gas and test temperature relationship curve baseline emission difference number envelope area schematic diagram;

[0035] Figure 7 The present application is an emission gas and test time relationship curve diagram under different height conditions in the embodiment;

[0036] Figure 8 The present application is an emission gas and test temperature relationship curve diagram under h1 height condition in the embodiment;

[0037] Figure 9 The present application is an emission gas and test temperature relationship curve diagram under h2 height condition in the embodiment;

[0038] Figure 10 The present application is an emission gas and test temperature relationship curve diagram under h3 height condition in the embodiment;

[0039] Figure 11A graph of the relationship between the exhaust gas and the test temperature under the h4 height condition in the embodiment of the present application;

[0040] Figure 12 A graph of the relationship between the exhaust gas and the test temperature under the h5 height condition in the embodiment of the present application;

[0041] Figure 13 A graph of the relationship between the exhaust gas and the test temperature under the h6 height condition in the embodiment of the present application.

[0042] REFERENCE NUMERALS

[0043] 1 - sealed box; 2 - gas sensor; 3 - temperature sensor; 4 - gas reading device; 5 - temperature reading device; 6 - upper cover; 7 - air filling hole; 8 - sensor connecting rod; 9 - center column; 10 - temperature insulation layer. DETAILED DESCRIPTION

[0044] Other advantages and novel features of the present disclosure will be readily appreciated by those skilled in the art from the following detailed description, when taken in conjunction with the drawings.

[0045] It should be apparent that the foregoing description is merely illustrative of the embodiments of the present disclosure and that numerous other embodiments are possible without departing from the spirit and scope of the present disclosure. It should also be apparent that features described herein in the context of separate embodiments can be combined with each other, where appropriate.

[0046] It is also necessary to note that the drawings provided in the following embodiments only illustrate the basic concept of the present disclosure in a schematic manner, and only show the components related to the present disclosure in the drawings, not drawn according to the number, shape and size of the components when actually implemented, and the type, number and proportion of each component when actually implemented can be a random change, and the component layout type can also be more complex. In addition, in the following description, specific details are provided in order to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the aspects can be practiced without these specific details.

[0047] As shown in Figure 1 , Figure 2 , the embodiment of the present application provides a hot-mixed asphalt mixture carbon emission behavior and attenuation law evaluation method, which specifically comprises:

[0048] S1, construction and pre-operation of test environment.

[0049] In this embodiment, the organic glass sealed box 1 used for testing is placed at the laboratory ventilation, and it is ensured that there is no obstruction within the space range of 2m around the sealed box 1; the gas sensor 2, the temperature sensor 3, the gas reading device 4 and the temperature reading device 5 are installed inside the sealed box 1; the upper cover 6 of the sealed box 1 is closed, a certain amount of CO2 is filled through the inflation hole 7 of the upper cover 6, and then the inflation hole 7 is closed; after the CO2 concentration reading data is stable, the initial data is recorded, and the CO2 concentration is recorded again after 6h, the concentration data difference is less than 0.5%, and the air tightness of the sealed box 1 is confirmed; at the same time, the test accuracy of the temperature sensor 5 and the heat preservation of the sealed box 1 are detected by heat preservation of the sealed box 1.

[0050] S2, preparation and storage of asphalt mixture.

[0051] In this embodiment, the asphalt mixture is mixed according to the specification (for example, Highway Engineering Asphalt and Asphalt Mixture Test Regulations (JTGE20-2019)). The asphalt can use common base asphalt or modified asphalt, and warm mix asphalt can also be used; the aggregate can use common aggregate such as basalt and diabase; and the filler can use limestone powder and other materials. The mixing temperature of the asphalt mixture is 150℃-170℃, and the mixing time is controlled in the range of 90s-120s. According to the above technical index, the preparation of the asphalt mixture is completed, and the prepared asphalt mixture is placed in a constant temperature oven with a temperature range of 150℃-170℃ for storage for 5min-10min, so as to ensure the constant temperature of the asphalt mixture.

[0052] S3, carbon emission test preparation.

[0053] In the embodiment, the sealed box 1 with the installed sensor is placed in a constant temperature oven, and the internal temperature ranges from 150°C to 170°C. The step can be performed synchronously with the asphalt mixture mixing. The mixed asphalt mixture is loaded into the bottom of the sealed box 1 in 3-5 times, and the tamping rod is used for tamping after each loading to ensure that there is no gap in the internal asphalt mixture. After the loading is completed, the sealed box 1 is closed.

[0054] S4, reading and collecting of test data.

[0055] In the embodiment, the sealed box 1 is placed for 5-10 minutes, and the carbon emission data recording is started after the temperature sensor 3 reading is stable. The internal space of the sealed box is divided into 6 height regions (h1, h2, h3, h4, h5 and h6 from top to bottom), and the height h at the center position of each height region is used as a space geometric calibration parameter. The carbon emission data is obtained based on the data of the calibration position. The obtained data mainly includes the gas concentration P, the environmental temperature t and the test time T.

[0056] The test time T is determined based on the temperature change range of the asphalt mixture, the temperature change range of the asphalt mixture is 90°C-160°C, and the test time is the time experienced by the asphalt mixture temperature from 160°C to 90°C. In the time range, the gas concentration, environmental temperature and other related data of different test positions are recorded every 5-10 minutes. When the lower limit of the test temperature is reached, the final data is recorded, and the recorded data is arranged and the subsequent carbon emission behavior evaluation is performed.

[0057] It should be noted that in the embodiment, each group of carbon emission test is performed three times in parallel, and the test data is collected and arranged.

[0058] S5, carbon emission behavior and attenuation law evaluation. The step specifically includes the following sub-steps:

[0059] S51, drawing a correlation graph of different carbon emission data and test time and environmental temperature, including drawing a correlation graph of carbon emission data and test time and drawing a correlation graph of carbon emission data and environmental temperature.

[0060] The correlation graph of carbon emission data and test time takes the test time T as the independent variable X and the gas concentration P as the dependent variable Y, and draws an X-Y line graph. In the same coordinate system, n correlation curves are drawn, and each curve corresponds to the test height standard value h n Please refer to Figure 3The correlation between carbon emission data and ambient temperature is plotted using the ambient temperature t (standard test altitude) as the independent variable X and the gas concentration P as the dependent variable Y, forming an XY line graph. Since the ambient temperature t varies at different test times T, n relationship curves are plotted in an independent coordinate system. Each independent curve in the coordinate system corresponds to the standard test altitude h. n For reference Figure 4 .

[0061] S52, calculate the envelope area of ​​the baseline emission difference and related indicators.

[0062] The envelope area S of the carbon emission data versus the baseline emission difference at test time T. T-h Calculation, such as Figure 5 As shown, based on the line graph of the relationship between carbon emission data and test time T in the same coordinate system, for each test height standard value h, a first baseline parallel to the X-axis is drawn with the test start point as the first baseline point, and a second baseline perpendicular to the first baseline is drawn with the test end point as the second baseline point. The area of ​​the figure enclosed by the first baseline, the second baseline, and the related line is the envelope area S of the baseline emission difference under the corresponding test height standard value h. T-h .

[0063] The specific numerical calculation method is as follows: A linear regression is performed on the broken line representing the relationship between carbon emission data and the testing time T to obtain a regression curve and regression formula with a correlation coefficient greater than 0.96. A definite integral is then calculated on the regression formula over the interval [0, T] to obtain the definite integral value S. d Then use the definite integral value S d Subtract the y-coordinate of the test starting point q The product of the baseline emission difference number and the total test time T yields the envelope area S. T-h .

[0064] For the calculation of the envelope area St-h of the difference between carbon emission data and the baseline emission data at ambient temperature, such as... Figure 6 As shown, based on the line graph of carbon emission data versus ambient temperature t in an independent coordinate system, for each test time T, a first baseline parallel to the X-axis is drawn with the test start point as the first baseline point. Then, a second baseline perpendicular to the first baseline is drawn with the test end point as the second baseline point. The area enclosed by the first baseline, the second baseline, and the related line graph is the area S of the baseline emission difference under the corresponding test height standard value h. T-h For ambient temperature t and carbon emission data, the baseline emission difference envelope area S t-h The relationship needs to be calculated separately for each test height standard value h within an independent coordinate system. The specific numerical calculation method is the same as for S.T-h .

[0065] S53, determine the carbon emission behavior and attenuation law.

[0066] Wherein, the evaluation index of carbon emission behavior and attenuation law contains the baseline emission difference envelope area S h (S T-h Or S t-h ), envelope area standard value S o , deviation W, maximum diffusion rate K and limit diffusion concentration P max , the meaning and calculation method of each evaluation index are as follows:

[0067] S o = (S h1 +S h2 +S h3 +……+ S hn ) / n, wherein n is the number of test height partitions;

[0068] W=Max{|S hi -S o |}, i=1, 2, 3, 4, …, n;

[0069] P max is the maximum diffusion concentration value of the emission gas.

[0070] The carbon emission behavior and attenuation law are evaluated through these evaluation indexes.

[0071] Based on the same inventive concept, the embodiment also provides a hot-mixed asphalt mixture carbon emission behavior and attenuation law evaluation device, which comprises a sealed box 1 made of organic glass, which is used to provide a sealed environment for hot-mixed asphalt mixture carbon emission test. Wherein, the sealed box 1 is provided with an upper cover 6, the upper cover 6 is provided with an inflation hole 7 for inflating the inside, and the upper cover 6 can be filled with asphalt mixture for testing after being opened. As a preferred embodiment, the sealed box 1 is made of organic glass material with a thickness of 2-4cm, which is bonded at the joint position by glass cement to ensure sealing, and the air tightness needs to be tested and confirmed.

[0072] The sealed box 1 is internally provided with a gas sensor 2, a temperature sensor 3 and corresponding gas reading equipment 4 and temperature reading equipment 5. Wherein, the gas sensor 2 mainly adopts a sensor capable of detecting CO x and NO x , and the working temperature range is 60-200℃. The CO x sensor test range is 0-1000ppm, and the test accuracy is 0.5ppm; the NO xThe sensor test range is 0-2500ppm, the test accuracy is 0~100ppm:+ / -10ppm, 100ppm~500ppm:+ / -10%, 500ppm~1500ppm:+ / -15%, 1500~2500ppm:+ / -30%. The temperature sensor 3 mainly adopts a sensor of thermistor, the working temperature range is -55℃-250℃, and the test accuracy is 0.1℃. The gas reading device 4 and the temperature reading device 5 are respectively used for reading the temperature of the gas sensor 2 and the temperature sensor 3, so as to facilitate the recording of corresponding data.

[0073] In the embodiment, the gas sensor 2 and the temperature sensor 3 are respectively arranged at different height positions in the sealed box 1 through the sensor connecting rod 8, so as to obtain the data at each h in the sealed box 1. As a preferred embodiment, the sensor connecting rod 8 is a stainless steel rod with a diameter of 0.5cm. The gas sensor 2 is connected with the side wall of the sealed box 1 through the sensor connecting rod 8, the tail end of the sensor connecting rod 8 is connected with the threaded hole of the side wall of the sealed box 1 through screw thread, and the front end is fixedly bonded with the gas sensor 2 through adhesive. The temperature sensor 3 is connected with the center column 9 located in the center of the sealed box 1 through the sensor connecting rod 8, and is also fixed through screw thread and bonding. The center column 9 is a cylindrical steel column with a diameter of 6cm-8cm, and the middle part of the steel column is reserved for the arrangement of the temperature sensor 3 and the reading device, and the arrangement gap is filled and sealed with sealing glue.

[0074] In addition, in order to further ensure the heat preservation of the sealed box 1, a temperature insulation layer 10 is arranged on the outer surface of the sealed box 1, which is coated on the outer surface of the sealed box 1 by using high-temperature-resistant heat-insulating and heat-preserving paint with a preferred thermal conductivity of 0.2W / m•K and a coating thickness range of 1-3mm.

[0075] It can be understood that, based on the foregoing need to obtain the data of 6 height positions, therefore, in the embodiment, the gas sensor 2 and the temperature sensor 3 are arranged at 6 height positions with 6 groups (including corresponding reading devices) respectively, so as to facilitate the subsequent evaluation of carbon emission behavior and decay law.

[0076] The following will further illustrate the scheme through a specific case. The sealed box 1 used for testing is placed in a ventilated place in the laboratory, and no obstructions are arranged within a space range of 2m around the sealed box 1. The gas sensor 2, the temperature sensor 3 and the related reading devices are installed in the sealed box 1. The upper cover 6 is closed, a certain amount of CO2 is filled through the inflation hole of the upper cover 6, and then the inflation hole 7 is closed. After the CO2 concentration reading data is stable, the initial data is recorded, and the CO2 concentration is recorded again after 6h. The recorded data is shown in Table 1. As shown in Table 1, the concentration data difference is 0.00408%, which is lower than 0.5%, and the test air tightness meets the requirements.

[0077] Table 1: CO2 concentration detection results

[0078]

[0079] At the same time, the heat preservation of the sealed box 1 is used to test the heat preservation and the test accuracy of the temperature sensor 3. When the temperature test results in the sealed box 1 are basically consistent, that is, the test accuracy of the temperature sensor 3 is good, it can be used for subsequent tests.

[0080] Table 2: Temperature detection results in the sealed box

[0081]

[0082] The asphalt mixture is mixed according to the “Highway Engineering Asphalt and Asphalt Mixture Test Regulations” (JTGE20-2019). The commonly used 70# base asphalt is used, the aggregate is basalt, the filler is limestone powder, and the asphalt mixture gradation is AC-13 dense gradation, which is specifically based on the gradation median value specified in the “Highway Asphalt Pavement Design Specification” (JTG D50-2017). The mixing temperature of the asphalt mixture is 160°C, and the mixing time is controlled within 90s. The prepared asphalt mixture is placed in a constant temperature oven with a temperature range of 160°C for 5min to ensure the temperature of the asphalt mixture is constant.

[0083] The sealed box 1 with the installed sensor is also placed in the constant temperature oven, and the internal temperature range is 160°C. This step is synchronized with the mixing of the asphalt mixture.

[0084] The mixed asphalt mixture is divided into three parts and placed in the bottom of the sealed box 1. After each filling is completed, a tamper is used for tamping to ensure that there is no gap in the asphalt mixture. After filling is completed, the sealed box 1 is closed.

[0085] The sealed sealed box 1 is placed for 5min, and the sensor temperature is stabilized before starting the carbon emission data recording. The test time is determined based on the temperature change range of the asphalt mixture, which is 90°C-160°C. The test time is the time taken for the temperature of the asphalt mixture to drop from 160°C to 90°C. In the sealed box 1 wrapped with the temperature insulation layer 10, the test time is about 100min. Within this time range, the gas concentration, ambient temperature and other related data at different test positions are recorded every 10min. When the lower limit of the test temperature is reached, the final data is recorded, and the recorded data is arranged and evaluated for subsequent carbon emission behavior. Each group of carbon emission tests is performed three times in parallel, and the test data is summarized. CO x is used as the main test gas, and the carbon emission data is mainly as follows:

[0086] Table 3: Ambient temperature test results at different test times and spatial positions

[0087]

[0088] Table 4: Gas emission test results at different test times and spatial positions

[0089]

[0090] Based on the aforementioned steps, a correlation diagram of different carbon emission data and test time and ambient temperature is drawn, which can be referred to as Figures 7-13 , the baseline emission difference envelope area and related indicators are calculated, and finally the carbon emission behavior and decay law are determined. The evaluation indicators include the baseline emission difference envelope area S h , the envelope area standard value S o , the deviation degree W, and the limit diffusion concentration P max . The evaluation indicator calculation values are shown in Table 5:

[0091] Table 5: Evaluation indicator calculation values (emission-time)

[0092]

[0093] Table 6: Evaluation indicator calculation values (emission-temperature)

[0094]

[0095] As can be seen from the curve diagram, the baseline emission difference envelope area S h-i has a good correlation with time, temperature, and test height, and increases significantly with the increase of temperature and time. High temperature can accelerate the diffusion and movement of emission gas, and at the same time, the change of height also affects the diffusion concentration of gas. Therefore, the quantitative analysis and evaluation of the carbon emission behavior and decay law of road construction asphalt mixture can be realized.

[0096] The technical features of the above embodiments can be combined in any way. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0097] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the application. It should be noted that for those skilled in the art, without departing from the concept of the present application, some modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A method for evaluating the carbon emission behavior and attenuation law of hot-mix asphalt mixtures, characterized in that, Includes the following steps: S1, the test environment is built and pre-run, the sealed box is installed, and the airtightness, heat preservation and accuracy of the sealed box and the sensor are tested; S2, Preparation and storage of asphalt mixture: Mix the asphalt mixture according to the specifications, put the prepared asphalt mixture into a constant temperature oven and store it at the preset temperature for a preset time to ensure that the temperature of the asphalt mixture is constant. S3, carbon emission test preparation: Place the sealed box in a constant temperature oven, and fill the bottom of the sealed box with the mixed asphalt mixture in multiple batches. After each filling, use a tamping stick to tamp the mixture to ensure that there are no voids inside the asphalt mixture. After filling, close the sealed box. S4, Reading and collecting test data: After the sealed test chamber is left to stand for a period of time, carbon emission data will be recorded after the sensor temperature stabilizes. The internal space of the test chamber is divided into multiple height zones. The height h at the center position of each height zone is used as the spatial geometric calibration parameter. The carbon emission data is obtained based on the data at the calibration position. The acquired data includes gas concentration P, ambient temperature t and test time T. S5. Based on the acquired data, plot the correlation between different carbon emission data and test time and ambient temperature, calculate the envelope area of ​​the baseline emission difference and evaluation indicators, and determine the carbon emission behavior and decay pattern. The correlation between carbon emission data and testing time is plotted using testing time T as the independent variable X and gas concentration P as the dependent variable Y. An XY line graph is created, and n relationship curves are plotted on the same coordinate system, with each curve corresponding to the standard value h of the testing height. n The correlation between carbon emission data and ambient temperature is plotted using the ambient temperature t (standard test altitude) as the independent variable X and the gas concentration P as the dependent variable Y. An XY line graph is then drawn, and n relationship curves are plotted in an independent coordinate system. Each independent curve in the coordinate system corresponds to the standard test altitude h. n ; The envelope area S of the difference between carbon emission data and the baseline emissions at test time T T-h The calculation is based on a line graph showing the relationship between carbon emission data and test time T in the same coordinate system. For each test height standard value h, a first baseline is drawn parallel to the X-axis, using the test start point as the first baseline point. Then, a second baseline is drawn perpendicular to the first baseline, using the test end point as the second baseline point. The area enclosed by the first baseline, the second baseline, and the related line graph is the area S of the baseline emission difference under the corresponding test height standard value h. T-h ; The envelope area S of the difference between carbon emission data and baseline emissions at ambient temperature t-h The calculation is based on a line graph showing the relationship between carbon emission data and ambient temperature t in an independent coordinate system. For each test time T, a first baseline is drawn parallel to the X-axis, using the test start point as the first baseline point. Then, a second baseline is drawn perpendicular to the first baseline, using the test end point as the second baseline point. The area enclosed by the first baseline, the second baseline, and the related line graph is the envelope area S of the baseline emission difference under the corresponding test height standard value h. t-h ; The evaluation indicators for carbon emission behavior and decay patterns include the baseline emission difference envelope area S. h Standard value of envelope area S o Deviation W, maximum diffusion rate K, and limiting diffusion concentration P max The meaning and calculation method are as follows: S o =(S h1 +S h2 +S h3 +……+ S hn ) / n, where n is the number of test height partitions; W=Max{|S hi -S o |},i=1,2,3,4,……,n; An evaluation device for the carbon emission behavior and attenuation law of hot-mix asphalt mixtures is provided. The device includes a sealed box made of plexiglass, with an insulation layer on the outer surface. The sealed box has an openable / closeable top cover with an inflation port for inflating the interior. Inside the sealed box are installed gas sensors, temperature sensors, and gas and temperature reading devices. The gas sensors are capable of detecting CO2. x and NO x The sensor is a thermistor sensor, and the gas reading device and the temperature reading device are used to read the temperature of the gas sensor and the temperature sensor, respectively. Multiple sets of gas sensors and temperature sensors are provided, and they are respectively connected to different height positions inside the sealed box through sensor connecting rods to obtain data at various heights h inside the sealed box.

2. The method for evaluating the carbon emission behavior and attenuation law of hot-mix asphalt mixtures according to claim 1, characterized in that, In step S1, the sealed box is placed in a well-ventilated area of ​​the laboratory, ensuring that there are no obstructions within a certain space around the box. Gas sensors, temperature sensors, and corresponding reading devices are installed inside the sealed box. The top cover of the sealed box is closed, and a certain amount of CO2 is introduced through the inflation port on the top cover, and then the inflation port is closed. After the CO2 concentration reading data stabilizes, the initial data is recorded. The CO2 concentration is recorded again after a period of time. If the difference in concentration data is less than 0.5%, the airtightness of the sealed box is confirmed. The accuracy of the temperature sensor test and the insulation performance of the sealed box are tested by insulating the sealed box.

3. The method for evaluating the carbon emission behavior and attenuation law of hot-mix asphalt mixtures according to claim 1, characterized in that, The mixing temperature range for S2 asphalt mixture is 150℃-170℃, and the mixing time range is 90s-120s. The prepared asphalt mixture is then placed in a constant temperature oven with a temperature range of 150℃-170℃ and stored for 5min-10min.

4. The method for evaluating the carbon emission behavior and attenuation law of hot-mix asphalt mixtures according to claim 1, characterized in that, In S3, the sealed box is placed in a constant temperature oven for heat preservation, and the mixing of asphalt mixture is carried out simultaneously; the mixed asphalt mixture is then poured into the bottom of the sealed box in 3-5 batches.

5. The method for evaluating the carbon emission behavior and attenuation law of hot-mix asphalt mixtures according to claim 1, characterized in that, In S4, the sealed chamber is left to stand for 5-10 minutes until the sensor temperature stabilizes before carbon emission data recording begins. The test time T is determined based on the temperature variation range of the asphalt mixture, which is 90℃-160℃. The test time is the time it takes for the asphalt mixture temperature to drop from 160℃ to 90℃. Within this time range, gas concentration and ambient temperature data at different test locations are recorded every 5-10 minutes. After the lower limit of the test temperature is reached and the final data is recorded, the recorded data is organized and subsequent carbon emission behavior is evaluated. Each group of carbon emission tests is conducted in parallel multiple times, and the test data are summarized and organized.

6. The method for evaluating the carbon emission behavior and attenuation law of hot-mix asphalt mixtures according to claim 1, characterized in that, The envelope area S of the difference between carbon emission data and the baseline emissions at test time T T-h The specific calculation method is as follows: A linear regression is performed on the broken line representing the relationship between carbon emission data and the testing time T to obtain a regression curve and regression formula with a correlation coefficient greater than 0.

96. A definite integral is then calculated on the regression formula over the interval [0, T] to obtain the definite integral value S. d Then use the definite integral value S d Subtract the y-coordinate of the test starting point q The product of the baseline emission difference number and the total test time T yields the envelope area S. T-h .

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