A quantitative evaluation method for aggregate adhesion based on the water boiling method

Abstract

A quantitative evaluation method for aggregate adhesion based on the boiling method is provided to solve the technical problem that the boiling method can only be used to qualitatively evaluate the adhesion performance of asphalt and aggregate, but cannot be used to quantify it. Quantitative evaluation method: 1. The boiling method is used to conduct a boiling test on the adhesion performance of asphalt and aggregate; 2. An industrial camera is used to capture four side images of the asphalt-coated aggregate and four side images of the boiled asphalt aggregate; 3. The background color of the side images is unified, and then the reflective area on the aggregate surface is eliminated by a two-stage de-reflection method to obtain a de-reflected aggregate image; 4. The asphalt spalling rate on the aggregate surface is calculated by calculating the area of ​​the four sides of the aggregate and the area of ​​asphalt spalling. The present invention combines the boiling method with an image processing method, eliminates the highlight area of ​​the image through a de-reflection algorithm, and accurately calculates the asphalt spalling area through an image method, thereby accurately judging the adhesion level of the aggregate.

Description

Technical Field

[0001] The invention belongs to the field of asphalt-aggregate adhesion evaluation, and particularly relates to a quantitative evaluation method for aggregate adhesion based on a water boiling method. Background Art

[0002] The adhesion between asphalt and aggregate is a key indicator of asphalt mixture resistance to water damage and durability. The current "Testing Procedures for Asphalt Mixtures for Highway Engineering" (JTG E20-2011) recommends using the water boiling method for adhesion testing. This method involves placing asphalt-coated aggregate in slightly boiling water for a period of time. The asphalt peeling off the stone surface is then visually observed to determine the adhesion between the asphalt and aggregate. This test, which relies on visual evaluation, provides only a qualitative assessment of asphalt-aggregate adhesion and lacks specific analytical indicators. Summary of the Invention

[0003] The present invention aims to solve the technical problem that the adhesion performance of asphalt and aggregate tested by the water boiling method can only be evaluated qualitatively but not quantified, and provides a quantitative evaluation method for aggregate adhesion based on the water boiling method.

[0004] The quantitative evaluation method of aggregate adhesion based on the water boiling method of the present invention is implemented by the following steps:

[0005] 1. Aggregate boiling test:

[0006] The aggregate particles are immersed in heated asphalt to completely coat the aggregate particles with the asphalt to obtain coated asphalt aggregates. The adhesion performance of the asphalt and the aggregate is then tested by boiling water to obtain boiled asphalt aggregates.

[0007] 2. Take four side images of the aggregate:

[0008] An industrial camera was used to obtain four side images of the coated asphalt aggregate and four side images of the boiled asphalt aggregate.

[0009] 3. Background and reflection removal of aggregate images:

[0010] Image processing software was used to uniformly color the four side images of the coated asphalt aggregate and the four side images of the boiled asphalt aggregate. Then, a two-stage de-reflection method was used to eliminate the reflective areas on the aggregate surface to obtain de-reflected aggregate images.

[0011] The process of the two-stage de-reflection method is as follows:

[0012] The first stage: grayscale processing is performed on the side image of the aggregate after the background color is unified. The following formula (1) is used to grayscale process the pixels of each side image to obtain the grayscale processed image;

[0013] c E =0.2989c R +0.5870c G +0.1140c B (1)

[0014] Where: c R ,c G and c B are the red channel intensity value, green channel intensity value and blue channel intensity value of each pixel respectively, c E Represents the grayscale value of each pixel;

[0015] The intensity at the 95th percentile is used as the highlight judgment, and the value r of the 95th percentile of the green intensity is calculated respectively. GE and the 95% percentile value of blue intensity r BE ;

[0016]

[0017] Among them, P 95 (c G ) is the 95% green channel intensity value, P 95 (c E ) is the 95% grayscale image intensity value, P 95 (c B ) is the 95th percentile blue channel intensity value;

[0018] Then the highlight pixel position is determined by the following formula (3), and the grayscale value of the pixel position x is c E (x), the green channel intensity value of pixel position x is c G (x), the blue channel intensity value of pixel position x is c B (x), the red channel intensity value of pixel position x is c R (x), T1 is the first threshold, when the pixel position x that satisfies formula (3) is the highlight pixel position;

[0019] c G (x)>r GE T1 and c B (x)>r BE T1 and c E (x)>T1 (3)

[0020] The second stage: median filtering is performed on the side image of the aggregate after the background color is unified. After median filtering, the red channel intensity value of each pixel at position x is The green channel intensity value is and the blue channel intensity value is The maximum value of the red channel intensity ratio, green channel intensity ratio and blue channel intensity ratio before and after median filtering is calculated according to the following formula (4);

[0021]

[0022] Set the second threshold When ε max (x) The pixel position x that satisfies formula (5) is the highlight pixel position;

[0023]

[0024] After the highlight detection in the first and second stages, the highlight pixels that satisfy formula (3) and formula (5) are all highlight areas. The highlight areas are eliminated and smoothing is performed using neighboring pixels to obtain the aggregate image after de-reflection.

[0025] 4. Calculate the spalling rate on each side of the aggregate and determine the adhesion grade:

[0026] The de-reflected aggregate image is binarized to obtain the black and white images of the asphalt-coated aggregate on the four sides and the black and white images of the asphalt-coated aggregate after boiling on the four sides. By counting the number of black pixels n in the black and white images, the asphalt-coated aggregate areas of the four sides are calculated as S and S, respectively. c1 、S c2 、S c3 and S c4 Calculate the asphalt peeling area of ​​the asphalt coated aggregate after boiling on the four sides in the black and white images respectively. p1 、S p2 、S p3 and S p4 , the asphalt stripping rate pr of the aggregate surface is calculated according to the following formula (6);

[0027]

[0028] The asphalt stripping rate pr of the aggregate surface is obtained by calculation, thereby determining the aggregate adhesion grade.

[0029] The present invention combines the water boiling method and image processing method to evaluate asphalt-aggregate adhesion. The highlight area of ​​the image is eliminated by a de-reflection algorithm, thereby improving the calculation accuracy of the asphalt spalling area. At the same time, the asphalt spalling area can be accurately calculated through the image method, thereby being able to (relatively) accurately judge the adhesion level of the aggregate and reduce the error of human eye judgment.

[0030] The quantitative evaluation method for aggregate adhesion based on the water boiling method of the present invention has the following beneficial effects:

[0031] (1) It avoids the subjectivity of the current “boiling method” in evaluating aggregate adhesion;

[0032] (2) The present invention optimizes the image processing method, which can more accurately calculate the asphalt stripping rate of the aggregate surface, thereby accurately evaluating the adhesion of the aggregate;

[0033] (3) This test method reduces test errors by unifying the background and eliminating reflection algorithms. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Flow chart of the quantitative evaluation method of aggregate adhesion based on the water boiling method of the present invention;

[0035] Figure 2 This is an experimental photo of the asphalt aggregate after drying and boiling in the embodiment;

[0036] Figure 3 Images of four sides (Figures a-d) of the tuff aggregate beneath the long-term aged asphalt after water boiling in step 2 of Example;

[0037] Figure 4 The four side views (Figures a to d) of the boiled asphalt aggregate in step 3 of the embodiment are processed with a uniform background color;

[0038] Figure 5 for Figure 4 a Pixel histogram before and after background uniformization and de-reflection processing;

[0039] Figure 6 for Figure 4 b Pixel histogram before and after background uniformization and de-reflection processing;

[0040] Figure 7 for Figure 4 c Pixel histogram before and after background uniformization and de-reflection processing;

[0041] Figure 8 for Figure 4 d Pixel histogram before and after background uniformization and de-reflection processing;

[0042] Figure 9 These are the four side images of the coated asphalt aggregate after binarization in step 4 of the embodiment and the four side images of the asphalt aggregate after boiling in water. DETAILED DESCRIPTION

[0043] Specific embodiment 1: The quantitative evaluation method of aggregate adhesion based on the water boiling method in this embodiment is implemented according to the following steps:

[0044] 1. Aggregate boiling test:

[0045] The aggregate particles are immersed in heated asphalt to completely coat the aggregate particles with the asphalt to obtain coated asphalt aggregates. The adhesion performance of the asphalt and the aggregate is then tested by boiling water to obtain boiled asphalt aggregates.

[0046] 2. Take four side images of the aggregate:

[0047] An industrial camera was used to obtain four side images of the coated asphalt aggregate and four side images of the boiled asphalt aggregate.

[0048] 3. Background and reflection removal of aggregate images:

[0049] Image processing software was used to uniformly color the four side images of the coated asphalt aggregate and the four side images of the boiled asphalt aggregate. Then, a two-stage de-reflection method was used to eliminate the reflective areas on the aggregate surface to obtain de-reflected aggregate images.

[0050] The process of the two-stage de-reflection method is as follows:

[0051] The first stage: grayscale processing is performed on the side image of the aggregate after the background color is unified. The following formula (1) is used to grayscale process the pixels of each side image to obtain the grayscale processed image;

[0052] c E =0.2989c R +0.5870c G +0.1140c B (1)

[0053] Where: c R ,c G and c B are the red channel intensity value, green channel intensity value and blue channel intensity value of each pixel respectively, c E Represents the grayscale value of each pixel;

[0054] The intensity at the 95th percentile is used as the highlight judgment, and the value r of the 95th percentile of the green intensity is calculated respectively. GE and the 95% percentile value of blue intensity r BE ;

[0055]

[0056] Among them, P 95 (c G ) is the 95% green channel intensity value, P 95 (c E ) is the 95% grayscale image intensity value, P 95 (c B) is the 95th percentile blue channel intensity value;

[0057] Then the highlight pixel position is determined by the following formula (3), and the grayscale value of the pixel position x is c E (x), the green channel intensity value of pixel position x is c G (x), the blue channel intensity value of pixel position x is c B (x), the red channel intensity value of pixel position x is c R (x), T1 is the first threshold, when the pixel position x that satisfies formula (3) is the highlight pixel position;

[0058] c G (x)>r GE T1 and c B (x)>r BE T1 and c E (x)>T1 (3)

[0059] The second stage: median filtering is performed on the side image of the aggregate after the background color is unified. After median filtering, the red channel intensity value of each pixel at position x is The green channel intensity value is and the blue channel intensity value is The maximum value of the red channel intensity ratio, green channel intensity ratio and blue channel intensity ratio before and after median filtering is calculated according to the following formula (4);

[0060]

[0061] Set the second threshold When ε max (x) The pixel position x that satisfies formula (5) is the highlight pixel position;

[0062]

[0063] After the highlight detection in the first and second stages, the highlight pixels that meet formula (3) and formula (5) are all highlight areas. The highlight areas are eliminated and smoothing is performed using neighboring pixels to obtain the aggregate image after de-reflection.

[0064] 4. Calculate the spalling rate on each side of the aggregate and determine the adhesion grade:

[0065] The de-reflected aggregate image is binarized to obtain the black and white images of the asphalt-coated aggregate on the four sides and the black and white images of the asphalt-coated aggregate after boiling on the four sides. By counting the number of black pixels n in the black and white images, the asphalt-coated aggregate areas of the four sides are calculated as S and S, respectively. c1 、S c2 、Sc3 and S c4 Calculate the asphalt peeling area of ​​the asphalt coated aggregate after boiling on the four sides in the black and white images respectively. p1 、S p2 、S p3 and S p4 , the asphalt stripping rate pr of the aggregate surface is calculated according to the following formula (6);

[0066]

[0067] The asphalt stripping rate pr of the aggregate surface is obtained by calculation, thereby determining the aggregate adhesion grade.

[0068] The aggregate boiling method in step 1 of this embodiment is based on the "Test Procedures for Asphalt Mixtures for Highway Engineering" (JTGE20-2011), which proposes the use of the boiling method for adhesion testing.

[0069] This embodiment P 95 (c G ) is the 95% green channel intensity value, which means that the green channel intensity values ​​of all pixels in the image are arranged from low to high, and the 95% green channel intensity value (high value) is selected as P 95 (c G ).

[0070] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the water boiling test process in step 1 is as follows:

[0071] a. Wrap a thin wire around the middle of the aggregate particles, heat them in an oven at 100-110°C, immerse the heated aggregate particles in heated asphalt, and then hang the aggregate on a test stand and cool it at room temperature to obtain asphalt-coated aggregate;

[0072] b. Immerse the coated asphalt aggregate in a beaker filled with boiling water, take out the aggregate from the boiling water, and then put it into a container filled with room temperature water to cool to room temperature to obtain boiled asphalt aggregate.

[0073] Specific embodiment three: The difference between this embodiment and specific embodiment two is that in step a, the aggregate is placed in an oven at 100-110° C. and heated for 1 hour.

[0074] Specific embodiment 4: This embodiment differs from specific embodiment 2 in that the boiling time in step b is 3 minutes.

[0075] Specific embodiment 5: The difference between this embodiment and any one of specific embodiments 1 to 4 is that the image processing software described in step 3 adopts Photoshop software.

[0076] Specific embodiment six: The difference between this embodiment and any one of specific embodiments one to five is that in step three, the four side images of the coated asphalt aggregate and the four side images of the boiled asphalt aggregate are respectively processed with a unified background color, and the background color is set to purple.

[0077] Specific embodiment seven: This embodiment differs from any one of specific embodiments one to six in that the value of the first threshold T1 in step three is 220.

[0078] Specific embodiment eight: The difference between this embodiment and any one of specific embodiments one to seven is that in step four, when the asphalt stripping rate pr=0, the adhesion level=5; when the asphalt stripping rate 0<pr<10%, the adhesion level=4.

[0079] Specific embodiment 9: The difference between this embodiment and any one of specific embodiments 1 to 7 is that in step 4, when the asphalt stripping rate is 10%≦pr<30%, the adhesion level = 3; when the asphalt stripping rate is 30%≦pr<100%, the adhesion level = 2.

[0080] Specific embodiment 10: The difference between this embodiment and any one of specific embodiments 1 to 7 is that in step 4, when the asphalt stripping rate = 100%, the adhesion level = 1.

[0081] Example 1: The quantitative evaluation method of aggregate adhesion based on the water boiling method in this example is implemented according to the following steps:

[0082] 1. Aggregate boiling test:

[0083] Four types of lithologic aggregates (basalt, diabase, limestone and tuff) were selected as original samples and long-term aged No. 70 asphalt. The adhesion performance of asphalt and aggregate was tested by boiling method. Aggregates were fastened in the middle with a thin wire one by one and heated in a 105℃ oven for 1 hour. Then, the heated aggregates were immersed in the heated asphalt one by one and gently taken out so that the aggregate particles were completely covered by the asphalt film. After that, the aggregate particles covered with asphalt were hung on the test frame (such as Figure 2 As shown), excess asphalt is drained off and cooled at room temperature for 15 minutes to obtain coated asphalt aggregate, which is then immersed in a beaker filled with boiling water and boiled for 3 minutes. The aggregate is then taken out of the water and placed in a container filled with room temperature water to cool to room temperature, and then dried to obtain boiled asphalt aggregate;

[0084] 2. Take four side images of the aggregate:

[0085] An industrial camera was used to obtain four side images of the coated asphalt aggregate and four side images of the boiled asphalt aggregate.

[0086] 3. Background and reflection removal of aggregate images:

[0087] Image processing software was used to uniformly color the four side images of the coated asphalt aggregate and the four side images of the boiled asphalt aggregate. Then, a two-stage de-reflection method was used to eliminate the reflective areas on the aggregate surface to obtain de-reflected aggregate images.

[0088] The process of the two-stage de-reflection method is as follows:

[0089] The first stage: grayscale processing is performed on the side image of the aggregate after the background color is unified. The following formula (1) is used to grayscale process the pixels of each side image to obtain the grayscale processed image;

[0090] c E =0.2989c R +0.5870c G +0.1140c B (1)

[0091] Where: c R ,c G and c B are the red channel intensity value, green channel intensity value and blue channel intensity value of each pixel respectively, c E Represents the grayscale value of each pixel;

[0092] The intensity at the 95th percentile is used as the highlight judgment, and the value r of the 95th percentile of the green intensity is calculated respectively. GE and the 95% percentile value of blue intensity r BE ;

[0093]

[0094] Among them, P 95 (c G ) is the 95% green channel intensity value, P 95 (c E ) is the 95% grayscale image intensity value, P 95 (c B ) is the 95th percentile blue channel intensity value;

[0095] Then the highlight pixel position is determined by the following formula (3), and the grayscale value of the pixel position x is c E (x), the green channel intensity value of pixel position x is c G (x), the blue channel intensity value of pixel position x is c B (x), the red channel intensity value of pixel position x is c R (x), T1 is the first threshold, T1 is 220, when the pixel position x that satisfies formula (3) is the highlight pixel position;

[0096] c G (x)>r GE T1 and c B (x)>r BE T1 and c E (x)>T1 (3)

[0097] The second stage: median filtering is performed on the side image of the aggregate after the background color is unified. After median filtering, the red channel intensity value of each pixel at position x is The green channel intensity value is and the blue channel intensity value is The maximum value of the red channel intensity ratio, green channel intensity ratio and blue channel intensity ratio before and after median filtering is calculated according to the following formula (4);

[0098]

[0099] Set the second threshold When ε max (x) The pixel position x that satisfies formula (5) is the highlight pixel position;

[0100]

[0101] After the highlight detection in the first and second stages, the highlight pixels that meet formula (3) or formula (5) are all highlight areas. The highlight areas are eliminated and smoothing is performed using neighboring pixels to obtain the aggregate image after de-reflection.

[0102] 4. Calculate the spalling rate on each side of the aggregate and determine the adhesion grade:

[0103] The de-reflected aggregate image was binarized and the background color was removed to obtain the black and white images of the asphalt-coated aggregate on the four sides and the black and white images of the asphalt-coated aggregate after boiling on the four sides. The number of black pixels n in the black and white images was counted and the image size (l×b) and the total number of pixels were used to calculate (n p ×n l ), calculate the area of ​​asphalt-coated aggregate S c and water-boiled asphalt coated aggregate area S l , (the area calculation method is shown in formula (6)), the area of ​​asphalt peeling S p Calculated by formula (7);

[0104]

[0105] S p =S c -S l (7)

[0106] The calculated areas of the asphalt-coated aggregate on the four sides are S c1 、S c2 、S c3 and S c4 The areas of asphalt peeling in the black and white images of the asphalt-coated aggregate after boiling on the four sides are S p1 、S p2 、S p3 and S p4 , the asphalt stripping rate pr of the aggregate surface is calculated according to the following formula (8);

[0107]

[0108] The asphalt stripping rate pr of the aggregate surface is obtained by calculation, thereby determining the aggregate adhesion grade.

[0109] This embodiment unifies the background of the aggregate as follows Figure 4 As shown in the figure. Using Matlab to analyze the pixel histograms before and after image processing, it can be seen that the original image has a large pixel span. Without processing, it is easy to identify parts of the image that are not asphalt-covered or peeling as asphalt-covered or peeling areas. After using a unified background, the pixel frequency of a small segment is very high, that is, background image pixels, making them more easily identified as background. This background removal method can improve recognition accuracy. Furthermore, it can be seen that the reflective surface of the aggregate is eliminated, which also improves recognition accuracy.

[0110] In this embodiment, the aggregate image is converted to black and white by adjusting the image binarization threshold, and the area S of each image is calculated respectively. c and S l , and then use the following formula to calculate the asphalt peeling area S on the aggregate surface p The area of ​​each part is shown in Table 2. The calculated S c Area 22.35cm 2 , asphalt peeling of aggregate surface S p Area 2.63cm 2 Based on this, the asphalt spalling rate on the aggregate surface was calculated to be 11.8%. Based on the standards in Table 1, the aggregate adhesion grade was determined to be Level 3. Table 3 shows a comparison of the image calculation results with those obtained by experienced testers using this method for several types of lithologic aggregates and different asphalt boiling methods. As can be seen from the table, the results obtained using the improved evaluation method are generally consistent with the empirical evaluation results. However, for test results at the boundary of the adhesion grading index, the modified evaluation method of this embodiment showed higher accuracy.

[0111] Table 1 Adhesion grade of asphalt and aggregate

[0112]

[0113]

[0114] Table 2 Area of ​​each figure (cm 2 )

[0115] picture <![CDATA[S c ]]> <![CDATA[S l ]]> <![CDATA[S p ]]> Figure 4 a 6.1 5 1.1 Figure 4 b 5.3 4.94 0.36 Figure 4 c 5.27 4.37 0.9 Figure 4 d 5.68 5.41 0.27

[0116] Table 3 Evaluation results of improved evaluation method and empirical method

[0117]

Claims

1. A quantitative evaluation method for aggregate adhesion based on the water boiling method, characterized in that The quantitative evaluation method is implemented according to the following steps:

1. Aggregate boiling test: The aggregate particles are immersed in heated asphalt to completely coat the aggregate particles with the asphalt to obtain coated asphalt aggregates. The adhesion performance of the asphalt and the aggregate is then tested by boiling water to obtain boiled asphalt aggregates.

2. Take four side images of the aggregate: An industrial camera was used to obtain four side images of the coated asphalt aggregate and four side images of the boiled asphalt aggregate.

3. Background and reflection removal of aggregate images: Image processing software was used to uniformly color the four side images of the coated asphalt aggregate and the four side images of the boiled asphalt aggregate. Then, a two-stage de-reflection method was used to eliminate the reflective areas on the aggregate surface to obtain de-reflected aggregate images. The process of the two-stage de-reflection method is as follows: The first stage: grayscale processing is performed on the side image of the aggregate after the background color is unified. The following formula (1) is used to grayscale process the pixels of each side image to obtain the grayscale processed image; c E =0.2989c R +0.5870c G +0.1140c B (1) Where: c R ,c G and c B are the red channel intensity value, green channel intensity value and blue channel intensity value of each pixel respectively, c E Represents the grayscale value of each pixel; The intensity at the 95th percentile is used as the highlight judgment, and the value r of the 95th percentile of the green intensity is calculated respectively. GE and the 95% percentile value of blue intensity r BE ; Among them, P 95 (c G ) is the 95% green channel intensity value, P 95 (c E ) is the 95% grayscale image intensity value, P 95 (c B ) is the 95th percentile blue channel intensity value; Then the highlight pixel position is determined by the following formula (3), and the grayscale value of the pixel position x is c E (x), the green channel intensity value of pixel position x is c G (x), the blue channel intensity value of pixel position x is c B (x), the red channel intensity value of pixel position x is c R (x), T1 is the first threshold, when the pixel position x that satisfies formula (3) is the highlight pixel position; c G (x) > r GE ·T1 and c B (x) > r BE ·T1 and c E (x) > T1 (3) The second stage: median filtering is performed on the side image of the aggregate after the background color is unified. After median filtering, the red channel intensity value of each pixel at position x is The green channel intensity value is and the blue channel intensity value is The maximum value of the red channel intensity ratio, green channel intensity ratio and blue channel intensity ratio before and after median filtering is calculated according to the following formula (4); Set the second threshold When ε max (x) The pixel position x that satisfies formula (5) is the highlight pixel position; After the highlight detection in the first and second stages, the highlight pixels that meet formula (3) and formula (5) are all highlight areas. The highlight areas are eliminated and smoothing is performed using neighboring pixels to obtain the aggregate image after de-reflection.

4. Calculate the spalling rate on each side of the aggregate and determine the adhesion grade: The de-reflected aggregate image is binarized to obtain the black and white images of the asphalt-coated aggregate on the four sides and the black and white images of the asphalt-coated aggregate after boiling on the four sides. By counting the number of black pixels n in the black and white images, the asphalt-coated aggregate areas of the four sides are calculated as S and S, respectively. c1 、S c2 、S c3 and S c4 Calculate the asphalt peeling area of ​​the asphalt coated aggregate after boiling on the four sides in the black and white images respectively. p1 、S p2 、S p3 and S p4 , the asphalt stripping rate pr of the aggregate surface is calculated according to the following formula (6); The asphalt stripping rate pr of the aggregate surface is obtained by calculation, thereby determining the aggregate adhesion grade.

2. The quantitative evaluation method for aggregate adhesion based on the water boiling method according to claim 1 is characterized in that The boiling test process in step 1 is as follows: a. Wrap a thin wire around the middle of the aggregate particles, heat them in an oven at 100-110°C, immerse the heated aggregate particles in heated asphalt, and then hang the aggregate on a test stand and cool it at room temperature to obtain asphalt-coated aggregate; b. Immerse the coated asphalt aggregate in a beaker filled with boiling water, take out the aggregate from the boiling water, and then put it into a container filled with room temperature water to cool to room temperature to obtain boiled asphalt aggregate.

3. The quantitative evaluation method for aggregate adhesion based on the water boiling method according to claim 2, characterized in that In step a, the aggregate is placed in an oven at 100-110° C. and heated for 1 hour.

4. The quantitative evaluation method for aggregate adhesion based on the water boiling method according to claim 2, characterized in that The boiling time in step b is 3 minutes.

5. The quantitative evaluation method for aggregate adhesion based on the water boiling method according to claim 1, characterized in that The image processing software described in step 3 adopts Photoshop software.

6. The quantitative evaluation method for aggregate adhesion based on the water boiling method according to claim 1, characterized in that In step 3, the four side images of the coated asphalt aggregate and the four side images of the boiled asphalt aggregate are respectively processed with a unified background color, and the background color is set to purple.

7. The quantitative evaluation method for aggregate adhesion based on the water boiling method according to claim 1, characterized in that The value of the first threshold T1 in step three is 220.

8. The quantitative evaluation method for aggregate adhesion based on the water boiling method according to claim 1, characterized in that In step 4, when the asphalt stripping rate pr=0, the adhesion level=5; when the asphalt stripping rate 0<pr<10%, the adhesion level=4.

9. The quantitative evaluation method for aggregate adhesion based on the water boiling method according to claim 1, characterized in that In step 4, when the asphalt stripping rate is 10%≦pr<30%, the adhesion level is 3; when the asphalt stripping rate is 30%≦pr<100%, the adhesion level is 2.

10. The quantitative evaluation method of aggregate adhesion based on the water boiling method according to claim 1, characterized in that In step 4, when the asphalt stripping rate = 100%, the adhesion level = 1.

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