Method and device for detecting diffusion characteristic of RAP coarse aggregate

Abstract

The invention discloses a method and a device for detecting diffusion characteristics of RAP coarse aggregate, and relates to the technical field of determination of road building materials, and the method comprises the following steps: weighing transparent colloid, new aggregate and RAP coarse aggregate according to a matching proportion; respectively heating the new aggregate and the transparent colloid; pouring the heated new aggregate and transparent colloid into stirring equipment at the same time, and stirring to obtain a first mixture; pouring RAP coarse aggregate to be detected into stirring equipment, and stirring the RAP coarse aggregate with the first mixture to obtain a second mixture; pouring the second mixture into a test mold, cooling and demolding to obtain a detection sample; measuring the detection sample, and calculating the diffusion coefficient of the RAP coarse aggregate in the detection sample; and determining the diffusion characteristic of the RAP coarse aggregate according to the diffusion coefficient. Through introduction of transparent colloid and stirring equipment, RAP coarse aggregate distribution in a detection sample is closer to actual pavement construction, and the reliability and authenticity of a test result are improved.

Description

Technical Field

[0001] The invention relates to the technical field of determination of road construction materials, and in particular to a method and a device for detecting diffusion characteristics of RAP coarse aggregate. Background Art

[0002] In the field of road engineering, accurate evaluation of the diffusion characteristics of RAP coarse aggregate in asphalt mixtures with RAP coarse aggregate is crucial to ensure the quality of pavement. However, the existing detection methods include simulation molding method and on-site sampling analysis method.

[0003] The simulation molding method is to mix RAP coarse aggregate with asphalt and new aggregate in proportion in the laboratory, use a press and other equipment to mold test pieces, and then measure the distribution of RAP coarse aggregate by cutting, microscopic observation or chemical analysis, and calculate the diffusion coefficient. The molding process of this method is very different from the actual construction, and it cannot simulate the dynamic distribution and compaction during the paving process. The experimental results cannot truly reflect the diffusion situation in the actual project. The operation is complicated, requires professional equipment and technicians, and the detection efficiency is low. The on-site sampling and analysis method is to extract mixture samples containing RAP coarse aggregate from the paved road surface, and evaluate the diffusion situation through physical property testing, image analysis, etc. The on-site sampling and analysis method can only obtain limited samples and cannot cover various road conditions. The sampled samples are prone to change during transportation and analysis, affecting the reliability of the test results. Therefore, the existing detection methods are difficult to effectively simulate construction conditions, and lack clear diffusion characteristics evaluation standards, resulting in the inability to accurately judge the performance of RAP mixtures in actual applications. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a detection method and a detection device which can simulate construction conditions, accurately measure diffusion coefficients to characterize diffusion characteristics, and have clear evaluation standards.

[0005] In order to solve the above technical problems, the present invention provides a method for detecting the diffusion characteristics of RAP coarse aggregate in a first aspect, comprising the following steps:

[0006] Weigh the transparent colloid, new aggregate and RAP coarse aggregate according to the mixing ratio;

[0007] The new aggregate and the transparent colloid are heated separately;

[0008] Pour the heated new aggregate and the transparent colloid into a stirring device at the same time and stir them to obtain a first mixed material;

[0009] Pour the RAP coarse aggregate to be tested into a mixing device and mix it with the first mixed material to obtain a second mixed material;

[0010] Pour the second mixed material into a test mold, and demould it after cooling to obtain a test sample;

[0011] Measuring the test sample and calculating the diffusion coefficient of RAP coarse aggregate in the test sample;

[0012] The diffusion characteristics of the RAP coarse aggregate are determined based on the diffusion coefficient.

[0013] As an improvement of the above scheme, the specific steps of measuring the test sample and calculating the diffusion coefficient of the RAP coarse aggregate in the test sample are:

[0014] Placing the test sample on a horizontal surface, defining two transverse sides of the test sample as a first side and a second side, and defining two longitudinal sides of the test sample as a third side and a fourth side;

[0015] Measuring the transverse length a and the longitudinal length b of the test sample;

[0016] Respectively measuring and calculating the lateral diffusion length Lx and the longitudinal diffusion length Ly of the RAP coarse aggregate on the test sample;

[0017] The diffusion coefficient D in the test sample is calculated using the formula: D=(Lx+Ly) / (a+b).

[0018] As an improvement of the above scheme, the specific steps of measuring and calculating the lateral diffusion length Lx of the RAP coarse aggregate on the test sample are:

[0019] Select at least three RAP coarse aggregates closest to the first side, measure the distance from each of the RAP coarse aggregates to the first side, and calculate an average value L1;

[0020] Select at least three RAP coarse aggregates closest to the second side, measure the distance from each of the RAP coarse aggregates to the second side, and calculate an average value L2;

[0021] The lateral diffusion length Lx=a-L1-L2.

[0022] As an improvement of the above scheme, the specific steps of measuring and calculating the longitudinal diffusion length Ly of the RAP coarse aggregate on the test sample are:

[0023] Select at least three RAP coarse aggregates closest to the third side, measure the distance from each of the RAP coarse aggregates to the third side, and calculate an average value L3;

[0024] Select at least three RAP coarse aggregates closest to the fourth side, measure the distance from each of the RAP coarse aggregates to the fourth side, and calculate an average value L4;

[0025] The longitudinal diffusion length Ly=b-L3-L4.

[0026] As an improvement of the above scheme, the specific steps of determining the diffusion characteristics of RAP coarse aggregate according to the diffusion coefficient are:

[0027] If the diffusion coefficient D is greater than or equal to the set value, it is determined that the diffusion performance of the RAP coarse aggregate under the mix ratio is good and meets the engineering requirements;

[0028] If the diffusion coefficient D is less than the set value, it is determined that the diffusivity of the RAP coarse aggregate under the mix ratio does not meet the requirements.

[0029] As an improvement of the above scheme, the specific steps of heating the new aggregate and the transparent colloid respectively are:

[0030] The transparent colloid is heated to 130°C to 150°C to melt the transparent colloid into liquid; and the new aggregate is heated to 100°C to 120°C.

[0031] As an improvement on the above scheme, the heated new aggregate and transparent colloid are poured into the stirring device at the same time for stirring for 5 minutes to 8 minutes, and the stirring speed is 60r / min to 90r / min. During stirring, the temperature in the stirring device is maintained greater than or equal to 135°C.

[0032] As an improvement of the above scheme, the RAP coarse aggregate to be tested is poured into a mixing device and mixed with the first mixture for a mixing time of 3 minutes to 5 minutes and a mixing speed of 20 r / min to 50 r / min. During mixing, the temperature in the mixing device is maintained greater than or equal to 135°C.

[0033] As an improvement of the above solution, the transparent colloid is hot melt adhesive or polymethyl methacrylate, and the density of the transparent colloid is 1.00 g / cm3 to 1.20 g / cm3.

[0034] In a second aspect, the present invention provides a device for detecting the diffusion characteristics of RAP coarse aggregate, comprising: a silo for storing materials; a heating component disposed in the silo; a spiral shaft rotatably disposed in the silo, the spiral shaft being used to stir the materials; a drive motor disposed outside the silo, the power output end of the drive motor being connected to the spiral shaft; a test mold disposed below the discharge port of the silo; and a measuring component for detecting a test sample demolded from the test mold.

[0035] The beneficial effects of implementing the present invention are:

[0036] The present invention discloses a method for detecting the diffusion characteristics of RAP coarse aggregate. The method uses a transparent colloid to simulate asphalt for heating and stirring. After the test sample is formed, the diffusion state of the RAP coarse aggregate in the sample can be clearly observed. The transparent colloid, new aggregate and RAP coarse aggregate are stirred by using a stirring device, so that the distribution of the RAP coarse aggregate in the test sample is closer to the actual pavement construction, thereby improving the reliability and authenticity of the test result. The concept of diffusion coefficient is established, and a diffusion coefficient evaluation standard is proposed, which is helpful to quickly judge whether the mixture meets the engineering requirements and improve the quality control efficiency.

[0037] A detection device for the diffusion characteristics of RAP coarse aggregate in the present invention can simulate the actual mixing work at the construction site in the test room by arranging a spiral shaft in the silo, so that the test samples obtained by mixing in the experiment are closer to the actual pavement construction, and the reliability and authenticity of the test results are improved; while ensuring the accuracy of the detection, the equipment requirements are simplified, and the test can be carried out without purchasing expensive and complex equipment. The construction site can also use the device to conduct preliminary detection of the quality of the mixture, which is simple to operate, low cost, and easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a process flow chart of a method for detecting diffusion characteristics of RAP coarse aggregate in this embodiment;

[0039] Figure 2 It is a structural schematic diagram of a detection device for the diffusion characteristics of RAP coarse aggregate in this embodiment.

[0040] The following are the descriptions of the reference numerals:

[0041] 100. silo; 200. spiral shaft; 300. drive motor; 400. test mold. DETAILED DESCRIPTION

[0042] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0043] In this embodiment, RAP aggregate refers to recycled asphalt mixture, which is a mixture made by digging up, recycling, crushing, and screening old asphalt pavement and then remixing it with asphalt materials, new aggregates, etc. in a certain proportion. New aggregate refers to new aggregate.

[0044] See also Figure 1 , Figure 1 is a process flow chart of a method for detecting diffusion characteristics of RAP coarse aggregate in this embodiment, such as Figure 1 As shown, the detection method comprises the following steps:

[0045] S1: Weigh transparent colloid, new aggregate and RAP coarse aggregate according to the mixing ratio;

[0046] Specifically, the transparent colloid, new aggregate and RAP coarse aggregate are screened, cleaned, dried and weighed according to the mix ratio. The transparent colloid is hot melt adhesive or polymethyl methacrylate; it has good thermal stability, does not react with the mixture components, and has stable heating and cooling performance; after processing, the distribution state of new aggregate and RAP coarse aggregate can be clearly observed in the test sample; the density of the transparent colloid is: 1.00g / cm3~1.20g / cm3, which is close to the density of new asphalt during actual processing, and the density of new asphalt is 1.0g / cm3~1.1g / cm3, which can more realistically simulate the actual mixing effect.

[0047] S2: heating the new aggregate and the transparent colloid respectively;

[0048] Specifically, the transparent colloid is heated to 130° C. to 150° C. to melt the transparent colloid into liquid; the new aggregate is heated to 100° C. to 120° C. to keep the new aggregate dry for easy mixing.

[0049] S3: pouring the heated new aggregate and the transparent colloid into a stirring device at the same time and stirring them to obtain a first mixed material;

[0050] Specifically, the heated new aggregate and the transparent colloid are poured into the stirring device at the same time for stirring for 5 minutes to 8 minutes, and the stirring speed is 60r / min to 90r / min; during stirring, the temperature in the stirring device is maintained greater than or equal to 135°C to ensure that the transparent colloid does not solidify; the stirring speed is the same as the stirring speed during construction, which can more realistically simulate the stirring effect.

[0051] S4: pouring the RAP coarse aggregate to be tested into a mixing device and mixing it with the first mixed material to obtain a second mixed material;

[0052] Specifically, the RAP coarse aggregate to be tested is poured into the mixing equipment and mixed with the first mixture for a mixing time of 3min to 5min, and a mixing speed of 20r / min to 50r / min; during mixing, the temperature in the mixing equipment is maintained greater than or equal to 135°C to ensure that the transparent colloid does not solidify. The rotation speed can be accurately controlled at 20r / min to 50r / min by the frequency converter, which matches the speed range of the spiral distributor of the actual construction paver. By first mixing the new aggregate and the transparent colloid, and then adding the RAP coarse aggregate, the material can be prevented from agglomerating and the uniformity of the test sample can be controlled; the rap aggregate does not need to be heated. During mixing, the liquid colloid is coated with a protective film on its surface due to the cold, ensuring that during the mixing process, the old asphalt on the rap surface is not dissolved due to mixing friction or high temperature.

[0053] S5: pouring the second mixture into a test mold, demoulding after cooling, and obtaining a test sample;

[0054] Specifically, the second mixed material is dropped into the mold; the uniformity of the material in the mold is observed, the surface of the mold opening is scraped flat with a steel ruler, and the mold is placed on a horizontal table to cool naturally to room temperature to form a test sample.

[0055] S6: measuring the test sample and calculating the diffusion coefficient of the RAP coarse aggregate in the test sample;

[0056] Specifically, the specific steps of measuring the test sample and calculating the diffusion coefficient of the RAP coarse aggregate in the test sample are:

[0057] Placing the test sample on a horizontal surface, defining two transverse sides of the test sample as a first side and a second side, and defining two longitudinal sides of the test sample as a third side and a fourth side;

[0058] Measuring the transverse length a and the longitudinal length b of the test sample;

[0059] Respectively measuring and calculating the lateral diffusion length Lx and the longitudinal diffusion length Ly of the RAP coarse aggregate on the test sample;

[0060] The specific steps of measuring and calculating the lateral diffusion length Lx of the RAP coarse aggregate on the test sample are as follows:

[0061] At least three RAP coarse aggregates closest to the first side are selected, and the distance from each of the RAP coarse aggregates to the first side is measured respectively, and an average value L1 is calculated. Preferably, 6 to 8 RAP coarse aggregates are selected for measurement.

[0062] Select at least 3 RAP coarse aggregates closest to the second side, measure the distance from each of the RAP coarse aggregates to the second side, and calculate the average value L2; preferably, select 6 to 8 RAP coarse aggregates for measurement.

[0063] The lateral diffusion length Lx=a-L1-L2.

[0064] The specific steps of measuring and calculating the longitudinal diffusion length Ly of the RAP coarse aggregate on the test sample are as follows:

[0065] Select at least 3 RAP coarse aggregates closest to the third side, measure the distance from each RAP coarse aggregate to the third side, and calculate the average value L3; preferably, select 6 to 8 RAP coarse aggregates for measurement

[0066] Select at least 3 RAP coarse aggregates closest to the fourth side, measure the distance from each RAP coarse aggregate to the fourth side, and calculate to obtain an average value L4; preferably, select 6 to 8 RAP coarse aggregates for measurement.

[0067] The longitudinal diffusion length Ly=b-L3-L4.

[0068] The diffusion coefficient D in the test sample is calculated using the formula: D=(Lx+Ly) / (a+b).

[0069] S7: Determine the diffusion characteristics of the RAP coarse aggregate based on the diffusion coefficient.

[0070] Specifically, if the diffusion coefficient D is greater than or equal to a set value, and the set value is 60% to 80%, it is determined that the diffusion performance of the RAP coarse aggregate under the mixing ratio is good and meets the engineering requirements;

[0071] If the diffusion coefficient D is less than the set value, it is determined that the diffusion of the RAP coarse aggregate under the mix ratio does not meet the requirements; the reasons can also be comprehensively analyzed based on the diffusion coefficient, and improvement suggestions can be made through analysis of its formula, process, etc., such as adjusting the RAP coarse aggregate dosage, gradation or mixing, and the speed of the spiral distribution. At the same time, the test data under the formula and process are recorded, and the relationship between the diffusion coefficient and the mixing speed, distribution speed, RAP coarse aggregate content and other factors is analyzed to establish a quantitative relationship model.

[0072] In other embodiments, the evaluation standard of the diffusion coefficient can be appropriately adjusted according to the engineering requirements and material properties of different regions. For example, in some areas with higher requirements for road quality, the evaluation standard can be increased to more than 90%; while in some special projects, such as low-traffic roads, the evaluation standard can be appropriately lowered. However, such adjustments require a lot of experimental verification and engineering practice experience support, otherwise it may affect the quality of the project.

[0073] Further, when measuring the distance from the RAP coarse aggregate to any side, place the test sample on a horizontal surface, use a steel ruler to mark a measurement position every 5 cm in the length and width directions of the test sample, and use a vernier caliper to measure the distance from the outer edge of the RAP coarse aggregate to the side. Each coarse aggregate is measured three times, and the middle value is taken to ensure the accuracy of the measurement. In other embodiments, an electronic distance meter can be used instead of a vernier caliper and a steel ruler for measurement. Electronic distance meters have higher measurement accuracy and automation, but they are expensive and require power supply, which may not be convenient to use at some construction sites. Although the vernier caliper and steel ruler have relatively low accuracy, the method of taking the average value through multiple measurements can also meet the test requirements, and they are low-cost, simple to operate, and do not require additional power supply, which is more suitable for the actual application scenario of this test.

[0074] As can be seen from the above, a method for detecting the diffusion characteristics of RAP coarse aggregate in the present invention uses a transparent colloid to simulate asphalt for heating and stirring, and the diffusion state of the RAP coarse aggregate in the sample can be clearly observed after the test sample is formed; by using a stirring device to stir the transparent colloid, new aggregate and RAP coarse aggregate, the distribution of RAP coarse aggregate in the test sample is closer to the actual pavement construction, thereby improving the reliability and authenticity of the test results; the concept of diffusion coefficient is established, and a diffusion coefficient evaluation standard is proposed, which helps to quickly determine whether the mixture meets the engineering requirements and improves the quality control efficiency.

[0075] See also Figure 2 , Figure 2 It is a structural schematic diagram of a detection device for the diffusion characteristics of RAP coarse aggregate in this embodiment. In the second aspect, the present invention provides a detection device for the diffusion characteristics of RAP coarse aggregate, including: a silo 100 for storing materials; a heating component, arranged in the silo; a spiral shaft 200, rotatably arranged in the silo 100, and the spiral shaft 200 is used to stir the materials; a driving motor 300, arranged outside the silo 100, and the power output end of the driving motor 300 is connected to the spiral shaft 200; a test mold 400, arranged below the discharge port of the silo 100; a measuring component, used to detect the demolded test sample in the test mold.

[0076] Specifically, in this embodiment, the heating component includes a heating resistor and a temperature sensor disposed on the inner wall of the silo 100. The temperature sensor and the heating resistor are used to keep the temperature in the silo 100 constant during stirring to prevent the transparent colloid from solidifying.

[0077] Specifically, in this embodiment, the silo 100 is made of stainless steel, with a capacity of 25L to 35L. The lower end of the silo 100 is bucket-shaped to facilitate the falling of the mixed material. The discharge port of the silo 100 is located at the bottom of the silo 100, and the discharge port is 25cm to 35cm long and 15cm to 25cm wide.

[0078] Specifically, in this embodiment, the spiral shaft 200 is arranged on one side of the silo 100 close to the discharge port, the diameter of the spiral shaft 200 is 8cm~10cm, the pitch is 8cm~12cm, the spiral blade thickness is 2.5mm~3.5mm, and the spiral shaft 200 is made of high-strength alloy steel, which is strong and wear-resistant.

[0079] Specifically, in this embodiment, the power of the driving motor 300 is 500W, and the speed is adjustable from 0 r / min to 100 r / min. The speed of the driving motor 300 is controlled by a frequency converter.

[0080] Specifically, in this embodiment, the test mold 400 is a rectangular parallelepiped, and a card slot is provided on the test mold 400. The card slot is 4 cm to 8 cm high, and the transverse cross-sectional area of ​​the card slot matches the size of the discharge port; the inner wall of the card slot is polished to a roughness of less than 0.8 μm to facilitate demolding; the experimental mold is made of steel plate or hard plastic plate.

[0081] Furthermore, the slot of the test mold 400 is connected to the discharge port of the silo 100 through a quick bayonet for easy disassembly and installation, and a sealing gasket is provided at the connection between the slot and the discharge port to ensure that the mixed material does not leak during the transmission process.

[0082] Furthermore, four adjusting bolts for leveling are provided at the bottom of the test mold 400. The adjusting precision of the adjusting bolts is 0.1 mm, which ensures that the mold is level and the thickness of the test piece is uniform.

[0083] Furthermore, the measuring assembly includes a steel ruler and a vernier caliper, which are low-cost, simple to operate, and do not require an additional power supply, and are more suitable for the actual application scenario of this experiment.

[0084] As can be seen from the above, a detection device for the diffusion characteristics of RAP coarse aggregate in the present invention can simulate the actual mixing work at the construction site in the test room by arranging a spiral shaft 200 in the silo 100, so that the test samples obtained by mixing in the experiment are closer to the actual pavement construction, and the reliability and authenticity of the test results are improved; while ensuring the accuracy of the detection, the equipment requirements are simplified, and the test can be carried out without purchasing expensive and complex equipment. The construction site can also use this device to conduct preliminary detection of the quality of the mixture. The operation is simple, the cost is low, and it is easy to promote.

[0085] The diffusion characteristics of RAP coarse aggregate are tested in combination with specific embodiments below:

[0086] Step 1: Weigh transparent colloid, new aggregate and RAP coarse aggregate according to the mixing ratio of 5:2:3; the transparent colloid is hot melt adhesive, and the density of the hot melt adhesive is 1.1 g / cm3; set the setting value of the diffusion coefficient D to 60%.

[0087] Step 2: Heat the transparent colloid to 145° C. to melt the transparent colloid into liquid; heat the new aggregate to 100° C. to keep the new aggregate dry for easy mixing.

[0088] Step 3: Pour the heated new aggregate and the transparent colloid into the silo 100 at the same time for stirring. The stirring time is 6 minutes and the stirring speed is 80 r / min. During stirring, the temperature in the silo 100 is greater than or equal to 135° C. through the heating component to ensure that the transparent colloid does not solidify.

[0089] Step 4: Pour the RAP coarse aggregate into the silo 100 for stirring, the stirring time is 5 minutes, and the stirring speed is 50 r / min; during stirring, the temperature in the silo 100 is greater than or equal to 135° C. through the heating component to ensure that the transparent colloid does not solidify.

[0090] Step 5: Pour the stirred material into the test mold 400, observe the uniformity of the material in the mold, use a steel ruler to scrape the surface of the mold opening flat, place it on a horizontal table and cool it naturally to room temperature to form a test sample.

[0091] Step 6: measuring the test sample and calculating the diffusion coefficient of the RAP coarse aggregate in the test sample;

[0092] Specifically, the test sample is placed on a horizontal surface, two transverse sides of the test sample are defined as a first side and a second side, and two longitudinal sides of the test sample are defined as a third side and a fourth side;

[0093] The transverse length a of the test sample is measured to be 30.1 cm, and the longitudinal length b is measured to be 19.9 cm;

[0094] Select 7 RAP coarse aggregates closest to the first side, measure the distances from each RAP coarse aggregate to the first side, measure each distance three times, and take the average value. The specific data are as follows:

[0095]

[0096] From the above, we can see that L1=6.04cm.

[0097] Select 7 RAP coarse aggregates closest to the second side, measure the distance from each RAP coarse aggregate to the second side, measure each distance three times, and take the average value. The specific data are as follows:

[0098]

[0099] From the above, we can know that L2 = 4.01cm. According to the formula Lx = a-L1-L2, we can calculate Lx = 20.05cm

[0100] Select 7 RAP coarse aggregates closest to the third side, measure the distance from each RAP coarse aggregate to the third side, measure each distance three times, and take the average value. The specific data are as follows:

[0101]

[0102] From the above, we can see that L3=2.01cm.

[0103] Select 7 RAP coarse aggregates closest to the fourth side, measure the distance from each RAP coarse aggregate to the fourth side, measure each distance three times, and take the average value. The specific data are as follows:

[0104]

[0105] From the above, we can see that L4=3.01cm. According to the formula Ly=b-L3-L4, we can calculate that Ly=14.88cm.

[0106] According to the calculation formula of diffusion coefficient D, we know that D = (20.05 + 14.88) / (30.1 + 19.9) = 70%

[0107] Step 7: Since the calculated diffusion coefficient is greater than the set value, the diffusion performance of the RAP coarse aggregate under the mix ratio in this embodiment is good and meets the engineering requirements.

[0108] In summary, the present invention can accurately evaluate the diffusion characteristics of RAP coarse aggregate, the test results have high reliability and authenticity, can clearly define the diffusion characteristic evaluation standard, and can accurately judge the performance of RAP coarse aggregate in practical applications.

[0109] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for detecting diffusion characteristics of RAP coarse aggregate, characterized in that: The following steps are involved: Weigh the transparent colloid, new aggregate and RAP coarse aggregate according to the mixing ratio; The new aggregate and the transparent colloid are heated separately; Pour the heated new aggregate and the transparent colloid into a stirring device at the same time and stir them to obtain a first mixed material; Pour the RAP coarse aggregate to be tested into a mixing device and mix it with the first mixed material to obtain a second mixed material; Pour the second mixed material into a test mold, and demould it after cooling to obtain a test sample; Measuring the test sample and calculating the diffusion coefficient of RAP coarse aggregate in the test sample; The diffusion characteristics of the RAP coarse aggregate are determined based on the diffusion coefficient.

2. The method for detecting diffusion characteristics of RAP coarse aggregate according to claim 1, characterized in that: The specific steps of measuring the test sample and calculating the diffusion coefficient of the RAP coarse aggregate in the test sample are: Placing the test sample on a horizontal surface, defining two transverse sides of the test sample as a first side and a second side, and defining two longitudinal sides of the test sample as a third side and a fourth side; Measuring the transverse length a and the longitudinal length b of the test sample; Respectively measuring and calculating the lateral diffusion length Lx and the longitudinal diffusion length Ly of the RAP coarse aggregate on the test sample; The diffusion coefficient D in the test sample is calculated using the formula: D=(Lx+Ly) / (a+b).

3. The method for detecting diffusion characteristics of RAP coarse aggregate according to claim 2, characterized in that: The specific steps of measuring and calculating the lateral diffusion length Lx of the RAP coarse aggregate on the test sample are: Select at least three RAP coarse aggregates closest to the first side, measure the distance from each of the RAP coarse aggregates to the first side, and calculate an average value L1; Select at least three RAP coarse aggregates closest to the second side, measure the distance from each of the RAP coarse aggregates to the second side, and calculate an average value L2; The lateral diffusion length Lx=a-L1-L2.

4. The method for detecting diffusion characteristics of RAP coarse aggregate according to claim 2, characterized in that: The specific steps of measuring and calculating the longitudinal diffusion length Ly of the RAP coarse aggregate on the test sample are: Select at least three RAP coarse aggregates closest to the third side, measure the distance from each of the RAP coarse aggregates to the third side, and calculate an average value L3; Select at least three RAP coarse aggregates closest to the fourth side, measure the distance from each of the RAP coarse aggregates to the fourth side, and calculate an average value L4; The longitudinal diffusion length Ly=b-L3-L4.

5. The method for detecting diffusion characteristics of RAP coarse aggregate according to claim 2, characterized in that: The specific steps of determining the diffusion characteristics of RAP coarse aggregate according to the diffusion coefficient are: If the diffusion coefficient D is greater than or equal to the set value, it is determined that the diffusion performance of the RAP coarse aggregate under the mix ratio is good and meets the engineering requirements; If the diffusion coefficient D is less than the set value, it is determined that the diffusivity of the RAP coarse aggregate under the mix ratio does not meet the requirements.

6. The method for detecting diffusion characteristics of RAP coarse aggregate according to claim 1, characterized in that: The specific steps of heating the new aggregate and the transparent colloid respectively are: The transparent colloid is heated to 130°C to 150°C to melt the transparent colloid into liquid; and the new aggregate is heated to 100°C to 120°C.

7. The method for detecting diffusion characteristics of RAP coarse aggregate according to claim 1, characterized in that: The heated new aggregate and the transparent colloid are poured into the stirring device at the same time for stirring for 5 to 8 minutes, and the stirring speed is 60 to 90 r / min. During stirring, the temperature in the stirring device is maintained to be greater than or equal to 135°C.

8. The method for detecting diffusion characteristics of RAP coarse aggregate according to claim 1, characterized in that: The RAP coarse aggregate to be tested is poured into a mixing device and mixed with the first mixed material for a mixing time of 3 to 5 minutes and a mixing speed of 20 to 50 r / min. During mixing, the temperature in the mixing device is maintained greater than or equal to 135°C.

9. The method for detecting diffusion characteristics of RAP coarse aggregate according to claim 1, characterized in that: The transparent colloid is hot melt adhesive or polymethyl methacrylate, and the density of the transparent colloid is 1.00 g / cm3 to 1.20 g / cm3.

10. A device for detecting diffusion characteristics of RAP coarse aggregate, characterized in that: include: Silos, used to store materials; A heating component is arranged in the silo; A spiral shaft is rotatably disposed in the silo, and the spiral shaft is used to stir the material; A driving motor is arranged outside the silo, and a power output end of the driving motor is connected to the spiral shaft; A test mold is arranged below the discharge port of the silo; The measuring component is used to detect the demoulding test sample in the test mold.

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