Asphalt and aggregate adhesiveness evaluation method and equipment based on improved boiling method

Abstract

The invention discloses an asphalt and aggregate adhesiveness evaluation method and equipment based on an improved water boiling method, and relates to the technical field of hydraulic engineering asphalt concrete.The method comprises the steps that original stones are machined and polished, and aggregate with the uniform shape size and surface roughness is obtained; respectively heating the asphalt and the aggregate in a drying oven; weighing asphalt with a set mass, smearing the asphalt on the surface of the aggregate, and cooling to obtain an asphalt-aggregate sample; the set mass is equal to the sum of the standard mass and the loss mass; the standard mass is calculated according to the density of asphalt, the thickness of an asphalt film and the diameter of aggregate; the method comprises the following steps: performing a water boiling test on an asphalt-aggregate sample, recording the initial spalling time of asphalt, and determining the change rule of asphalt spalling area percentage and asphalt spalling rate along with time by adopting a continuous test method so as to judge the adhesiveness of the asphalt and the aggregate. According to the method, the adhesiveness of the asphalt and the aggregate can be quantitatively evaluated, and a more objective and accurate evaluation result is obtained.

Description

Technical Field

[0001] The present application relates to the technical field of hydraulic asphalt concrete, and in particular to a method and device for evaluating the adhesion between asphalt and aggregate based on an improved water boiling method. Background Art

[0002] During the operation of the dam, the asphalt concrete face plate or core wall is corroded by water molecules and the pressure of reservoir water for a long time, which can easily cause water stability damage. The main reason is that under the action of long-term water load, water molecules penetrate into the bonding interface between asphalt and aggregate, resulting in reduced adhesion between asphalt and aggregate, and then causing the performance of asphalt concrete to deteriorate. Therefore, the adhesion between asphalt and aggregate is the most important factor affecting the water stability of asphalt concrete. At present, the most commonly used method for evaluating the adhesion between asphalt and aggregate is the boiling method or water immersion method specified in the current specification "Test Procedure for Hydraulic Asphalt Concrete" (DL / T 5362-2018). This method is affected by parameters such as aggregate size, shape, surface roughness, and thickness of the coated asphalt film, and the test conditions and influencing factors are difficult to control. In addition, the degree of adhesion between asphalt and aggregate is not obvious, and there is a lack of quantitative evaluation indicators. The test results are mainly based on the visual judgment of the observer. The evaluation results vary from person to person, and are greatly affected by human subjective factors. Summary of the invention

[0003] The purpose of this application is to provide a method and device for evaluating the adhesion between asphalt and aggregate based on an improved water boiling method, which can quantitatively evaluate the adhesion between asphalt and aggregate and obtain more objective and accurate evaluation results.

[0004] To achieve the above objectives, this application provides the following solutions.

[0005] In the first aspect, the present application provides an asphalt-aggregate adhesion evaluation method based on an improved water boiling method, comprising: processing and grinding the original stone to obtain aggregates with uniform shape, size and surface roughness; placing the asphalt and aggregate in an oven for heating respectively; weighing a set mass of asphalt and applying it on the surface of the aggregate, and obtaining an asphalt-aggregate sample after cooling; the set mass is equal to the sum of the standard mass and the loss mass; the standard mass is calculated based on the density of the asphalt, the thickness of the asphalt film and the diameter of the aggregate; performing a water boiling test on the asphalt-aggregate sample, recording the initial peeling time of the asphalt, and using a continuity test method to determine the change pattern of the asphalt peeling area percentage and the asphalt peeling rate with time to judge the adhesion between the asphalt and the aggregate; wherein, the longer the initial peeling time of the asphalt, the smaller the asphalt peeling area percentage and the asphalt peeling rate at the same measurement time, and the better the adhesion between the asphalt and the aggregate; the shorter the initial peeling time of the asphalt, the larger the asphalt peeling area percentage and the asphalt peeling rate at the same measurement time, and the worse the adhesion between the asphalt and the aggregate.

[0006] In a second aspect, the present application provides a computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-mentioned asphalt-aggregate adhesion evaluation method.

[0007] According to the specific embodiments provided in this application, this application discloses the following technical effects.

[0008] The present application provides an asphalt-aggregate adhesion evaluation method and device based on an improved water boiling method, wherein the original stone is processed and polished to obtain aggregates with uniform shape, size and surface roughness, the asphalt and aggregate are respectively placed in an oven for heating, a set mass of asphalt is weighed and smeared on the surface of the aggregate, and an asphalt-aggregate sample is obtained after cooling, and the effects of the shape, size and surface roughness of the aggregate and the thickness of the asphalt film on the adhesion of the asphalt and the aggregate are taken into consideration, and the adhesion of the asphalt and the aggregate is quantitatively evaluated based on three evaluation indicators, namely, the initial peeling time of the asphalt, the percentage of the asphalt peeling area and the change law of the asphalt peeling rate over time, so as to obtain a more objective and accurate evaluation result. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0010] Figure 1 Flowchart of the asphalt-aggregate adhesion evaluation method provided for this application.

[0011] Figure 2 Experimental flow chart of the improved water boiling method provided for this application.

[0012] Figure 3 A two-dimensional topographic image of the aggregate provided for this application; Figure 3 Part (a) shows the two-dimensional morphology of limestone aggregate. Figure 3 Part (b) shows the two-dimensional morphology of basalt aggregate. Figure 3 Part (c) shows the two-dimensional morphology of granite aggregate.

[0013] Figure 4 This is a graph showing the test results of the improved water boiling method provided in this application.

[0014] Figure 5 Grayscale image of the test results of the improved water boiling method provided in this application.

[0015] Figure 6A graph showing the change in asphalt peeling area percentage over time provided for this application.

[0016] Figure 7 A schematic diagram of the structure of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0018] In order to solve the problems of the water boiling method, such as the large influence of human factors and the inability to quantify, the present application provides an asphalt-aggregate adhesion evaluation method and equipment based on the improved water boiling method, proposes a multi-dimensional evaluation standard for asphalt-aggregate adhesion, quantitatively studies the adhesion of asphalt and aggregate, solves the defects and shortcomings of the water boiling method in evaluating the adhesion of asphalt and aggregate, and provides a certain reference basis for evaluating the adhesion of asphalt and aggregate.

[0019] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0020] In an exemplary embodiment, the present application provides a method for evaluating the adhesion between asphalt and aggregate based on an improved water boiling method. In the present application embodiment, Figure 1 and Figure 2 As shown, the method includes the following steps S1 to S4.

[0021] Step S1: Processing and grinding the original stone to obtain aggregates with uniform shape, size and surface roughness. This step specifically includes the following steps (1) to (2).

[0022] Step (1) Preparation of test piece: using a core drilling sampler with a diameter of 50 mm to sample the original stone to obtain a core sample; using a CNC cutting and grinding machine to cut the core sample into a cylindrical standard sample with a height of 30 mm.

[0023] like Figure 3 As shown, the original stone is limestone, basalt or granite. The shape of the aggregate has an important influence on the adhesion evaluation results. In order to eliminate the influence of the aggregate shape, the aggregate is processed into a cylindrical standard specimen with uniform size.

[0024] Step (2) grinding the specimen: grinding the surface of the cylindrical standard specimen for 30 minutes using a vibration grinder equipped with 600-grit sandpaper to obtain an aggregate (i.e., a specimen), ensuring that the surface roughness of the aggregate is similar.

[0025] The vibration grinder is equipped with 600-grit sandpaper. There is a certain correspondence between the mesh number of the sandpaper and the roughness. The smaller the roughness of the sandpaper, the smoother the surface. During the grinding process, keeping the surface moist helps reduce friction and sandpaper clogging. According to the texture of the aggregate, grind in a uniform direction to avoid scratches and dents. Use a laser confocal microscope to evaluate whether the grinding accuracy of the aggregate surface is qualified. Place the polished aggregate sample on the stage and use a 10x focusing objective to observe the surface morphology of the aggregate. Before the test, adjust the brightness and upper and lower ranges of the view, and then obtain the information of the scanning area. Each scanning area is 2×2mm 2 , a total of 6 × 6 areas are scanned. Finally, the images of all the collected areas are stitched together, the surface texture data is extracted, and the surface roughness of the aggregate is calculated.

[0026] Step S2: asphalt and aggregate are placed in an oven for heating. This step specifically includes the following step (3).

[0027] Step (3) Heating: Heat the asphalt in an oven at 150°C to 160°C for 1 hour, and heat the aggregate in an oven at 105°C ± 5°C for 1 hour.

[0028] Step S3: Weigh a set mass of asphalt and apply it on the surface of the aggregate, and obtain an asphalt-aggregate sample after cooling. The set mass is equal to the sum of the standard mass and the loss mass. The standard mass is calculated based on the density of the asphalt, the thickness of the asphalt film and the diameter of the aggregate. This step specifically includes the following steps (4) to (5).

[0029] Step (4) Weighing: Determine the density of asphalt to be 1.0 g / cm 3 , the thickness of the asphalt film is 200mm, the diameter of the aggregate is 50mm, the mass of the asphalt can be approximately calculated as mg, and considering that the applicator will be stained with asphalt, the mass of the asphalt is determined to be m+0.2g; weigh the set mass (i.e. m+0.2g) of asphalt.

[0030] The density of asphalt is measured according to the requirements of the "Test Procedure for Hydraulic Asphalt Concrete" (DL / T 5362-2018). The specific formula is: Then according to the formula Calculate the mass of asphalt.

[0031] Where: is the density of asphalt, in g / cm 3; m1 is the mass of the density bottle, in g; m2 is the mass of the density bottle and water, in g; m3 is the mass of the density bottle and asphalt sample, in g; m4 is the mass of the density bottle, asphalt sample and water, in g; is the density of water. The density of water at 20°C is 0.998 g / cm 3 m is the standard mass of asphalt, in g; h is the thickness of asphalt film, in mm; r is the radius of aggregate, in mm.

[0032] Step (5) Applying asphalt: First, drop the weighed asphalt on the surface of the aggregate, and use a 200 mm thick applicator to slide evenly at a speed of 150 mm / s to form a 200 mm thick asphalt film on the surface of the aggregate. Then, place the aggregate coated with the asphalt film in a vacuum drying oven and cool for 1 hour to obtain an asphalt-aggregate sample, which is placed in a desiccator for curing and standby use.

[0033] The coater is a steel rod with four convex wave curves processed by cold extrusion technology. The surface is smooth and consists of a coating rod and a handle. It is used for high-precision coating of wet film thickness and is easy to operate. Before coating, the coater needs to be heated with a spray gun for 5 minutes. Considering that the coater will be stained with asphalt, the mass of asphalt is determined to be m+0.2g.

[0034] Step S4: Perform a water boiling test on the asphalt-aggregate sample, record the initial peeling time of the asphalt, and use a continuous test method to determine the variation of the asphalt peeling area percentage and the asphalt peeling rate over time to determine the adhesion between the asphalt and the aggregate. The longer the initial peeling time of the asphalt, the smaller the asphalt peeling area percentage and the asphalt peeling rate at the same measurement time, and the better the adhesion between the asphalt and the aggregate; the shorter the initial peeling time of the asphalt, the larger the asphalt peeling area percentage and the asphalt peeling rate at the same measurement time, and the worse the adhesion between the asphalt and the aggregate. This step specifically includes the following steps (6) to (9).

[0035] Step (6) Boiling: Immerse the asphalt-aggregate sample in the center of a beaker filled with water, and set the temperature of the heating furnace so that the water temperature in the beaker is 100° C. Perform a boiling test on the asphalt-aggregate sample and record the initial peeling time of the asphalt.

[0036] The initial peeling time of asphalt is the time from the beginning of recording the peeling of asphalt during water boiling to the time when the asphalt film begins to peel off from the surface of aggregate, resulting in the exposure of aggregate. Generally, the asphalt film begins to peel off from the periphery of the aggregate surface, and attention should be paid to observe the peeling of the asphalt film.

[0037] Step (7) Drying: Using the continuous test (5 min, 10 min, 15 min) method, at set intervals (e.g., 5 min) from the start of the water boiling test, remove the asphalt-aggregate sample from the water with a clamp and place it in a vacuum drying oven to dry for 1 h or use a hair dryer to dry the surface moisture.

[0038] Step (8) Image acquisition: The image acquisition system is used to acquire images of the dried asphalt-aggregate sample, and the asphalt stripping area percentage and asphalt stripping rate are calculated by digital image processing technology. The asphalt stripping area percentage is the ratio of the asphalt stripping area to the aggregate area.

[0039] Step (9) Adhesion determination: Determine the adhesion between asphalt and aggregate based on the initial asphalt peeling time, asphalt peeling area percentage and asphalt peeling rate changing over time.

[0040] Among them, the asphalt stripping area percentage and asphalt stripping rate are calculated by digital image processing technology, including: threshold processing of the collected image to obtain a grayscale image; calculating the ratio of the total number of pixels of the asphalt stripping area to the total number of pixels of the aggregate area to obtain the asphalt stripping area percentage; calculating the ratio of the asphalt stripping area percentage to time to obtain the asphalt stripping rate.

[0041] The water boiling test results were captured by an image acquisition system, and the images were analyzed using digital image processing technology to obtain the percentage of asphalt peeling on the aggregate surface to quantitatively evaluate the adhesion between asphalt and aggregate. There is no shadow in the acquired image, and the asphalt surface does not emit light. Figure 4 As shown, the acquired image is thresholded and converted into an 8-bit grayscale image, such as Figure 5 As shown in Figure 2, the grayscale thresholds representing the aggregate area and asphalt coating area range from 0 to 255. The total number of pixels in the asphalt peeling area S b Total number of pixels of aggregate area S a The ratio is the asphalt stripping rate R, and the calculation formula is: The asphalt peeling area percentages of the three groups of samples were calculated respectively, and the average value was taken as the final result.

[0042] Three examples are provided below to evaluate the adhesion between different types of asphalt and aggregate.

[0043] Example 1, a method for evaluating the adhesion between Karamay 70, 90, SBS and Haiyun 70, 90, SBS asphalt and limestone aggregate based on an improved water boiling method, is specifically implemented according to the following steps.

[0044] Step 1: Use a core drilling sampler with a diameter of 50 mm to sample the limestone block, and then use a CNC cutting and grinding machine to cut the drilled limestone core sample into a limestone cylinder standard sample with a height of 30 mm.

[0045] Step 2: Select 600-grit sandpaper and use a vibration grinder to uniformly grind the aggregate surface for 30 minutes. During the grinding process, keeping the surface moist helps reduce friction and sandpaper clogging. According to the texture of the aggregate, grind in a uniform direction to avoid scratches and dents. Place the polished aggregate sample on the stage and use a 10x focusing objective to observe the surface morphology of the aggregate. Before the test, adjust the brightness and upper and lower range of the view, and then obtain the information of the scan area. Each scan area is 2×2mm 2 , a total of 6 × 6 areas were scanned. Finally, the images of all the acquired areas were stitched together, the surface texture data were extracted, and the surface roughness of the limestone aggregate was calculated to be 5.168 μm.

[0046] Step 3: Heat Karamay No. 70, 90, SBS and Haiyun No. 70, 90, SBS asphalts in an oven at 150℃~160℃ for 1h, and heat the limestone aggregate in an oven at 105℃±5℃ for 1h.

[0047] Step 4: Determine the density of Karamay 70, 90, SBS and Haiyun 70, 90, SBS asphalt to be 0.986 g / cm 3 、0.963g / cm 3 , 1.026g / cm 3 , 1.035g / cm 3 , 1.031g / cm 3 , 1.025g / cm 3 , the thickness of the asphalt film is 200mm, and the diameter of the limestone aggregate is 50mm. According to the density formula, the approximate asphalt mass can be calculated to be 0.783g, 0.789g, 1.012g, 1.024g, 1.021g, and 1.009g respectively.

[0048] Step 5: Considering that the applicator will be stained with asphalt, the asphalt masses are determined to be 0.983g, 0.989g, 1.212g, 1.224g, 1.221g, and 1.209g, respectively. The weighed asphalt is dropped on the surface of the limestone aggregate with a small spoon. Before coating, the applicator needs to be heated. Use a spray gun to heat the applicator for 5 minutes. Use a 200mm thick applicator to slide at a constant speed of 150mm / s to form a 200mm thick asphalt film on the surface of the limestone aggregate.

[0049] Step 6: After the limestone specimen is cooled in the vacuum drying oven for 1 hour, it is placed in a desiccator for curing.

[0050] Step 7. Use a clamp to immerse the prepared limestone specimen into the center of a beaker filled with water. Set the heating furnace temperature so that the temperature in the beaker is 100°C. Record the initial peeling time of the asphalt. Generally, the asphalt film begins to peel off from the periphery of the aggregate surface. Pay attention to observe the peeling of the asphalt film.

[0051] Step 8. Use the continuous test method (5min, 10min, 15min) to determine the change in the asphalt peeling area of ​​the limestone specimen during the water boiling and peeling process. When the water boiling time reaches the set time, first use a clamp to take the limestone specimen out of the water, then use a hair dryer to dry the moisture on the surface of the limestone specimen, and use the image acquisition system to capture the image of the limestone specimen, and analyze the asphalt peeling area percentage through digital image processing technology. Among them, there is no shadow in the acquired image, and the asphalt surface does not emit light. The acquired image is gray-processed and converted into an 8-bit gray-scale image, in which the gray-scale threshold value range of the aggregate area and the asphalt coating area is between 0 and 255. The total number of pixels of the asphalt peeling area S b Total number of pixels of aggregate area S a The ratio is the asphalt peeling area percentage R.

[0052] The asphalt peeling area percentages of the three groups of samples were calculated respectively, and the average value was taken as the final result. The asphalt peeling rates R of limestone and Karamay 70, 90, SBS and Haiyun 70, 90, SBS were 2.41%, 3.45%, 2.48%, 2.53%, 3.56%, and 2.86%, respectively.

[0053] Example 2, a method for evaluating the adhesion between Karamay 70, 90, SBS and Haiyun 70, 90, SBS asphalt and basalt aggregate based on an improved water boiling method, is specifically implemented according to the following steps.

[0054] Step 1: Select a core drilling sampler with a diameter of 50 mm to sample the basalt block, and then cut the drilled basalt core sample into a basalt cylindrical standard sample with a height of 30 mm using a CNC cutting and grinding machine.

[0055] Step 2: Select 600-grit sandpaper and use a vibration grinder to uniformly grind the aggregate surface for 30 minutes. During the grinding process, keeping the surface moist helps reduce friction and sandpaper clogging. According to the texture of the aggregate, grind in a uniform direction to avoid scratches and dents. Place the polished aggregate sample on the stage and use a 10x focusing objective to observe the surface morphology of the aggregate. Before the test, adjust the brightness and upper and lower range of the view, and then obtain the information of the scan area. Each scan area is 2×2mm 2 , a total of 6 × 6 areas were scanned. Finally, the images of all the acquired areas were stitched together, the surface texture data were extracted, and the surface roughness of the basalt aggregate was calculated to be 5.258 μm.

[0056] Step 3: Heat Karamay No. 70, No. 90, SBS and Haiyun No. 70, No. 90, SBS asphalts in an oven at 150℃~160℃ for 1 hour, and heat basalt aggregate in an oven at 105℃±5℃ for 1 hour.

[0057] Step 4: Determine the density of Karamay 70, 90, SBS and Haiyun 70, 90, SBS asphalt to be 0.986 g / cm 3 、0.963g / cm 3 , 1.026g / cm 3 , 1.035g / cm 3 , 1.031g / cm 3 , 1.025g / cm 3 , the thickness of the asphalt film is 200mm, and the diameter of the limestone aggregate is 50mm. According to the density formula, the approximate mass of asphalt can be calculated as 0.783g, 0.789g, 1.012g, 1.024g, 1.021g, and 1.009g respectively.

[0058] Step 5: Considering that the applicator will be stained with asphalt, the asphalt masses are determined to be 0.983g, 0.989g, 1.212g, 1.224g, 1.221g, and 1.209g, respectively. The weighed asphalt is dropped on the surface of the basalt aggregate with a small spoon. Before coating, the applicator needs to be heated. The applicator is heated with a spray gun for 5 minutes. A 200mm thick asphalt film can be formed on the surface of the basalt aggregate by sliding the applicator at a constant speed of 150mm / s with a thickness of 200mm.

[0059] Step 6: After the basalt specimen is cooled in the vacuum drying oven for 1 hour, it is placed in a desiccator for curing.

[0060] Step 7. Use a clamp to immerse the prepared basalt specimen into the center of a beaker filled with water. Set the heating furnace temperature so that the temperature in the beaker is 100°C. Record the initial peeling time of the asphalt. Generally, the asphalt film begins to peel off from the periphery of the aggregate surface. Pay attention to observe the peeling of the asphalt film.

[0061] Step 8. Use the continuous test method (5min, 10min, 15min) to determine the change of asphalt peeling area over time during the water boiling and peeling process of basalt specimens. When the water boiling time reaches the set time, first use a clamp to remove the basalt specimen from the water, then use a hair dryer to dry the moisture on the surface of the basalt specimen, and use the image acquisition system to capture the image of the basalt specimen, and analyze the asphalt peeling area percentage R through digital image processing technology. Among them, there is no shadow in the acquired image, and the asphalt surface does not emit light. The acquired image is threshold processed and converted into an 8-bit grayscale image, where the grayscale threshold value representing the aggregate area and the asphalt coating area ranges from 0 to 255. The total number of pixels of the asphalt peeling area S b Total number of pixels of aggregate area S a The ratio is the asphalt peeling area percentage R.

[0062] The asphalt stripping area percentages of the three groups of samples were calculated respectively, and the average value was taken as the final result. The asphalt stripping rates R of basalt and Karamay 70, 90, SBS and Haiyun 70, 90, SBS were 15.22%, 24.74%, 9.37%, 9.16%, 11.48%, and 7.27%, respectively.

[0063] Example 3, a method for evaluating the adhesion between Karamay 70, 90, SBS and Haiyun 70, 90, SBS asphalt and granite aggregate based on an improved water boiling method, is specifically implemented according to the following steps.

[0064] Step 1: Use a core drilling sampler with a diameter of 50 mm to sample the granite block, and then use a CNC cutting and grinding machine to cut the drilled granite core sample into a 30 mm high granite cylindrical standard sample.

[0065] Step 2: Select 600-grit sandpaper and use a vibration grinder to uniformly grind the aggregate surface for 30 minutes. During the grinding process, keeping the surface moist helps reduce friction and sandpaper clogging. According to the texture of the aggregate, grind in a uniform direction to avoid scratches and dents. Place the polished aggregate sample on the stage and use a 10x focusing objective to observe the surface morphology of the aggregate. Before the test, adjust the brightness and upper and lower range of the view, and then obtain the information of the scan area. Each scan area is 2×2mm 2, a total of 6 × 6 areas were scanned. Finally, the images of all the acquired areas were stitched together, the surface texture data were extracted, and the surface roughness of the granite aggregate was calculated to be 5.346 μm.

[0066] Step 3: Heat Karamay No. 70, No. 90, SBS and Haiyun No. 70, No. 90, SBS asphalts in an oven at 150℃~160℃ for 1 hour, and heat basalt aggregate in an oven at 105℃±5℃ for 1 hour.

[0067] Step 4: Determine the density of Karamay 70, 90, SBS and Haiyun 70, 90, SBS asphalts to be 0.986 g / cm 3 、0.963g / cm 3 , 1.026g / cm 3 , 1.035g / cm 3 , 1.031g / cm 3 , 1.025g / cm 3 , the thickness of the asphalt film is 200mm, and the diameter of the limestone aggregate is 50mm. According to the density formula, the approximate asphalt mass can be calculated to be 0.783g, 0.789g, 1.012g, 1.024g, 1.021g, and 1.009g respectively.

[0068] Step 5: Considering that the applicator will be stained with asphalt, the asphalt masses are determined to be 0.983g, 0.989g, 1.212g, 1.224g, 1.221g, and 1.209g, respectively. The weighed asphalt is dropped on the surface of the granite aggregate with a small spoon. Before coating, the applicator needs to be heated. Use a spray gun to heat the applicator for 5 minutes. Use a 200mm thick applicator to slide at a constant speed of 150mm / s to form a 200mm thick asphalt film on the surface of the granite aggregate.

[0069] Step 6: After the granite specimen is cooled in the vacuum drying oven for 1 hour, place it in a desiccator for curing.

[0070] Step 7. Use a clamp to immerse the prepared granite specimen into the center of a beaker filled with water. Set the heating furnace temperature so that the temperature in the beaker is 100°C. Record the initial peeling time of the asphalt. Generally, the asphalt film begins to peel off from the periphery of the aggregate surface. Pay attention to observe the peeling of the asphalt film.

[0071] Step 8. Use the continuous test method (5min, 10min, 15min) to determine the change of asphalt spalling area over time during the water boiling and spalling process of the granite specimen. When the water boiling time reaches the set time, first use a clamp to take the granite specimen out of the water, then use a hair dryer to dry the moisture on the surface of the granite specimen, and use the image acquisition system to capture the image of the granite specimen, and analyze the percentage of asphalt spalling area through digital image processing technology. Among them, there is no shadow in the acquired image, and the asphalt surface does not emit light. The acquired image is threshold processed and converted into an 8-bit grayscale image, where the grayscale threshold value representing the aggregate area and the asphalt coating area ranges from 0 to 255. The total number of pixels of the asphalt spalling area S b Total number of pixels of aggregate area S a The ratio is the asphalt peeling area percentage R.

[0072] The asphalt stripping area percentages of the three groups of samples were calculated respectively, and the average value was taken as the final result. The asphalt stripping rates R of granite and Karamay 70, 90, SBS and Haiyun 70, 90, SBS were 35.16%, 48.79%, 22.41%, 38.48%, 46.72%, and 6.68%, respectively.

[0073] The adhesion evaluation results and test items of asphalt and aggregate of Examples 1 to 3 are as follows: Figure 1-Figure 6 As shown in Table 1-Table 2. Among them, Table 1 is the initial peeling time table of asphalt, and Table 2 is the variation rule table of asphalt peeling area percentage over time.

[0074] Table 1 Initial stripping schedule of asphalt

[0075] Table 2 Changes of asphalt peeling area percentage over time

[0076] As shown in Table 1, Table 2 and Figure 6 As shown in the figure, the adhesion test results of asphalt and aggregate measured by the improved boiling method show that with the increase of boiling time, the difference between the groups gradually increases, the percentage of asphalt peeling area increases, and the adhesion level between asphalt and aggregate decreases. At 15 minutes, the difference between the groups is obvious. The adhesion level between asphalt and aggregate is ranked as follows: HSBS>KSBS>K70>H70>H90>K90. The order of asphalt according to the length of initial peeling time is: HSBS>KSBS>K70>H70>H90>K90. The lower the asphalt grade, the smaller the needle penetration, and the better the adhesion between asphalt and aggregate.

[0077] In summary, the asphalt-aggregate adhesion evaluation method based on the improved water boiling method provided by the present application abandons the method of evaluating adhesion by observing the degree of peeling of the asphalt film, and considers the influence of aggregate shape, surface roughness and asphalt film thickness parameters on it, thereby quantitatively evaluating the adhesion of asphalt and aggregate, which is more objective and accurate than the adhesion grade of the water boiling method, and reduces the test error caused by human or other factors. The three evaluation indicators of the initial peeling time of asphalt, the percentage of asphalt peeling area, and the change law of asphalt peeling rate over time are used to judge the adhesion grade of asphalt and aggregate more accurately than visual inspection.

[0078] In an exemplary embodiment, the present application further provides a computer device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0079] In an exemplary embodiment, the present application also provides a computer device, which may be a server or a terminal, and its internal structure diagram may be as follows: Figure 7 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store processing data. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for evaluating the adhesion between asphalt and aggregate based on an improved water boiling method is implemented.

[0080] Those skilled in the art will understand that Figure 7 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0081] All actions to obtain signals, information or data in this application are carried out in compliance with the relevant data protection laws and policies of the country where they are located, and with the authorization given by the owner of the corresponding device.

[0082] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0083] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for evaluating adhesion between asphalt and aggregate based on an improved water boiling method, characterized in that: include: The original stones are processed and polished to obtain aggregates with uniform shape, size and surface roughness; The asphalt and aggregate are placed in an oven for heating; Weigh a set mass of asphalt and apply it on the surface of the aggregate, and obtain an asphalt-aggregate sample after cooling; the set mass is equal to the sum of the standard mass and the loss mass; the standard mass is calculated based on the density of the asphalt, the thickness of the asphalt film and the diameter of the aggregate; A boiling test was carried out on the asphalt-aggregate samples, the initial peeling time of the asphalt was recorded, and the continuity test method was used to determine the change pattern of the asphalt peeling area percentage and the asphalt peeling rate with time to judge the adhesion between the asphalt and the aggregate; among them, the longer the initial peeling time of the asphalt, the smaller the asphalt peeling area percentage and the asphalt peeling rate at the same measurement time, and the better the adhesion between the asphalt and the aggregate; the shorter the initial peeling time of the asphalt, the larger the asphalt peeling area percentage and the asphalt peeling rate at the same measurement time, and the worse the adhesion between the asphalt and the aggregate.

2. The asphalt-aggregate adhesion evaluation method based on the improved water boiling method according to claim 1 is characterized in that: The original stones are processed and polished to obtain aggregates with uniform shape, size and surface roughness, including: The original stone was sampled using a core drilling sampler with a diameter of 50 mm to obtain core samples; The core sample is cut into a cylindrical standard specimen with a height of 30 mm using a CNC cutting and grinding machine; The surface of the cylindrical standard sample was polished for 30 minutes using a vibration grinder equipped with 600-grit sandpaper to obtain aggregate.

3. The asphalt-aggregate adhesion evaluation method based on the improved water boiling method according to claim 1 is characterized in that: The asphalt and aggregate are placed in an oven for heating separately, including: Heat the asphalt in an oven at 150℃~160℃ for 1h, and heat the aggregate in an oven at 105℃±5℃ for 1h.

4. The method for evaluating adhesion between asphalt and aggregate based on the improved water boiling method according to claim 1, characterized in that: Weigh a set amount of asphalt and apply it on the surface of the aggregate. After cooling, the asphalt-aggregate sample is obtained, including: Weigh a set amount of asphalt and drop it on the surface of the aggregate. Use a 200mm thick applicator to slide evenly at a speed of 150mm / s to form a 200mm thick asphalt film on the surface of the aggregate. The aggregate coated with the asphalt film was placed in a vacuum drying oven to cool for 1 hour to obtain an asphalt-aggregate sample, which was placed in a desiccator for curing before use.

5. The method for evaluating adhesion between asphalt and aggregate based on the improved water boiling method according to claim 1, characterized in that: The asphalt-aggregate samples were boiled in water, the initial asphalt peeling time was recorded, and the asphalt peeling area percentage and the asphalt peeling rate were measured with the continuity test method to determine the adhesion between asphalt and aggregate, including: Immerse the asphalt-aggregate sample in the center of a beaker filled with water, and set the heating furnace temperature so that the water temperature in the beaker is 100°C. Perform a water boiling test on the asphalt-aggregate sample and record the initial peeling time T0 of the asphalt. A continuous test method is used. The asphalt-aggregate sample is taken out of the water and dried at set intervals from the start of the water boiling test. The image acquisition system is used to acquire images of the asphalt-aggregate sample, and the asphalt stripping area percentage and asphalt stripping rate are calculated by digital image processing technology. The adhesion between asphalt and aggregate is determined based on the initial asphalt peeling time, the percentage of asphalt peeling area and the change pattern of asphalt peeling rate over time.

6. The method for evaluating adhesion between asphalt and aggregate based on the improved water boiling method according to claim 5, characterized in that: The asphalt stripping area percentage and asphalt stripping rate are calculated by digital image processing technology, including: Perform threshold processing on the collected image to obtain a grayscale image; The ratio of the total number of pixels of the asphalt stripping area to the total number of pixels of the aggregate area is calculated to obtain the asphalt stripping area percentage; The ratio of the asphalt stripping area percentage to time is calculated to obtain the asphalt stripping rate.

7. The method for evaluating adhesion between asphalt and aggregate based on improved water boiling method according to claim 5, characterized in that: The set time is ∆tmin; the times for taking the asphalt-aggregate sample out of water are T0+∆tmin, T0+2∆tmin and T0+3∆tmin after the start of the water boiling test; wherein the value of ∆t is 5.

8. The method for evaluating adhesion between asphalt and aggregate based on the improved water boiling method according to claim 1, characterized in that: The loss mass of asphalt is 0.2g; the calculation formula of the standard mass of asphalt is: ； Wherein, m is the standard mass of asphalt, in g; is the density of asphalt, in g / cm 3 ; h is the thickness of the asphalt film, in mm; r is the radius of the aggregate, in mm.

9. The method for evaluating adhesion between asphalt and aggregate based on the improved water boiling method according to claim 1, characterized in that: The calculation formula of asphalt density is: ； in, is the density of asphalt, in g / cm 3 ; m1 is the mass of the density bottle, in g; m2 is the mass of the density bottle and water, in g; m3 is the mass of the density bottle and asphalt sample, in g; m4 is the mass of the density bottle, asphalt sample and water, in g; is the density of water. The density of water at 20°C is 0.998 g / cm 3 .

10. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the asphalt-aggregate adhesion evaluation method based on the improved water boiling method as described in any one of claims 1 to 9.

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