Evaluation method for storage stability of modified emulsified asphalt

Abstract

The invention discloses a method for evaluating the storage stability of modified emulsified asphalt, and belongs to the field of road engineering regeneration. According to the evaluation method, an ultraviolet lamp is utilized to excite the modifier to generate a fluorescence effect, and the storage stability of the modified emulsified asphalt is evaluated by observing the distribution change condition of the modifier. Preparing modified emulsified asphalt by adopting an external doping method, and placing the modified emulsified asphalt in a container for standing; in the standing period, modified emulsified asphalt samples are extracted from different depths of the container respectively, the samples are observed through a fluorescence microscope, binary images of an emulsified asphalt phase and a modifier phase are obtained after filtering analysis and segmentation treatment, and the content of the modified emulsified asphalt is calculated by comparing the fluorescence area difference. And analyzing the distribution change condition of the modifier phase in the emulsified asphalt phase along with the change of the storage time so as to evaluate the storage stability of the modified emulsified asphalt. Compared with a traditional method, the problem that the storage stability of the modified emulsified asphalt cannot be quantitatively evaluated is solved, and a solid foundation is laid for follow-up research on the technical performance of the modified emulsified asphalt.

Description

Technical Field

[0001] The invention relates to a method for evaluating the storage stability of modified emulsified asphalt, and belongs to the field of road engineering regeneration. Background Art

[0002] Emulsified asphalt refers to a homogeneous liquid formed by asphalt and emulsifier under mechanical shear force. It has the advantages of convenient construction, low cost, and environmental protection, and is widely used in road construction. Emulsified asphalt has good fluidity, but its rheological properties, durability, and adhesion to aggregates are poor. Adding an appropriate amount of modifier can significantly improve the technical performance of emulsified asphalt. Due to the difference in the properties of the modifier and emulsified asphalt, modified emulsified asphalt is prone to phase separation and other segregation phenomena during storage and use. This segregation phenomenon will reduce the modification effect of the modifier, thereby affecting the quality and performance of the emulsified asphalt. Therefore, it is of great significance to ensure the good storage stability of modified emulsified asphalt. However, the existing evaluation method for the storage stability of modified emulsified asphalt cannot quantitatively determine the distribution of the modifier in the emulsified asphalt, and cannot scientifically evaluate the storage stability of modified emulsified asphalt. Therefore, there is an urgent need for a method that can quantitatively evaluate the storage stability of modified emulsified asphalt. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for evaluating the storage stability of modified emulsified asphalt. The method proposes to treat the modifier with ultraviolet light to stimulate its fluorescence effect, and measure the fluorescence intensity and color number distribution of the same batch of modified emulsified asphalt at different storage times and different depths, which are used as technical indicators for evaluating the storage stability of modified emulsified asphalt. The greater the difference in the amount of modifier in the modified emulsified asphalt obtained at different depths, the worse the storage stability of the modified emulsified asphalt; conversely, the better the storage stability of the modified emulsified asphalt. The evaluation method can accurately reflect the distribution of the modifier in the emulsified asphalt, and the evaluation process is simple and efficient.

[0004] The present invention adopts the following technical solutions to solve the above technical problems:

[0005] 1. A method for evaluating the storage stability of modified emulsified asphalt, characterized in that it comprises the following steps:

[0006] Step 1: Use ultraviolet light to irradiate the modifier to stimulate its fluorescence effect and shoot it with a camera and use image J image processing software to record the gray value of the modifier;

[0007] Step 2: put the packaged 70# matrix asphalt into an oven and heat it at 155°C for 40 minutes. When the 70# matrix asphalt is in a flowing state, take it out for use. Then weigh a certain mass of distilled water in a beaker and place it on an electric furnace for heating. Then add emulsifier and other additives to the water in sequence according to the proportion and stir it thoroughly with a glass rod. Use a thermometer to measure the temperature of the liquid in the beaker in real time and keep it below 70°C. After there is no obvious sediment in the liquid, weigh the modifier according to the proportion, slowly add it to the soap solution in four times, stir it thoroughly with a glass rod, until there is no obvious agglomeration on the surface of the soap solution, turn on the colloid mill, preheat it with hot water, and when the temperature of the colloid mill reaches 65°C, slowly pour the thermochromic soap solution and the 70# matrix asphalt heated to 155°C into the colloid mill in proportion, shear it at a speed of 3000rpm for 5 minutes to make modified emulsified asphalt.

[0008] Step 3: slowly pour the modified emulsified asphalt into a container and seal it to let it stand. After 0h, 24h, 72h and 120h, extract the modified emulsified asphalt solution at a depth of 5cm and 25cm from the container, respectively, and observe and record it under a fluorescence microscope;

[0009] Step 4: Filter and analyze the collected fluorescence microscopic color image, and perform segmentation processing to obtain binary images of the emulsified asphalt phase and the modifier phase, extract the modifier phase state in the binary image, and perform block operation on the binary image main matrix, divide the binary image main matrix into several binary image sub-matrices, extract the number of connected domains of the binary image main matrix and the number of modifier particles in each binary image sub-matrix, calculate the proportion of the modifier fluorescence area and the gray value to characterize the distribution of the modifier;

[0010] Step 5: Determine the storage stability of the modified emulsified asphalt by comparing the gray values ​​at the depths of 5 cm and 25 cm after standing for 0 h, 24 h, 72 h and 120 h to determine the storage stability of the modified emulsified asphalt:

[0011]

[0012] Where: S refers to the fluorescence intensity ratio;

[0013] H t is the initial gray value of modified emulsified asphalt at a depth of 5 cm;

[0014] H′ t It is the gray value of the modified emulsified asphalt at a depth of 5 cm after standing for n hours;

[0015] H b is the initial gray value of modified emulsified asphalt at a depth of 25 cm;

[0016] H′ bIt is the gray value of the modified emulsified asphalt at a depth of 25 cm after being left standing for n hours.

[0017] Furthermore, the modifier selected in step 1 is a powdered particle, which can be excited to fluoresce under ultraviolet light, is insoluble in asphalt, and can be dispersed in emulsified asphalt.

[0018] Furthermore, during the filtering analysis in step 4, the color image is converted into a grayscale image to facilitate the calculation of the area ratio, the grayscale image is filtered using Wiener filters at different neighborhood levels, and the number of modifier particles in the filtered image is extracted.

[0019] Furthermore, the color image selected in step 4 should be a square, and the color and brightness of the modifier presented in the captured image should be used as variables, and the final grayscale value should be calculated using image J image processing software.

[0020] Furthermore, in step 4, the neighborhood level corresponding to when the number of particles tends to be stable is taken as the optimal neighborhood level, and the corresponding filtered image is taken as the final research object.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention uses a fluorescence microscope to measure the distribution of modifiers in the same batch of modified emulsified asphalt at different days and different depths, and proposes to use the ratio of the area of ​​the image occupied by modifier particles in the emulsified asphalt solution as a technical indicator of the storage stability of the modified emulsified asphalt. The operation is simple and efficient, and it is convenient for quantitatively evaluating the storage stability of the modified emulsified asphalt. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is described clearly and completely below.

[0024] The idea of ​​the present invention is to first use ultraviolet light to excite the modifier in the modified emulsified asphalt to produce a fluorescence effect, then extract modified emulsified asphalt samples at different storage times and different depths, observe and record them through a fluorescence microscope, and perform filtering analysis and segmentation processing to obtain binary images of emulsified asphalt and modifiers, extract the phase state of the modifier in the binary image, perform block operations on the main matrix of the binary image, divide the main matrix of the binary image into several binary image sub-matrices, extract the number of connected domains of the main matrix of the binary image and the number of modifier particles in each binary image sub-matrix, calculate the proportion of the modifier fluorescence area to characterize the distribution of the modifier, and quantitatively evaluate the storage stability of the modified emulsified asphalt.

[0025] In order to further understand the technical features of the present invention, the following will introduce the evaluation method of the storage stability of modified emulsified asphalt in combination with an implementation case, and the specific steps are as follows:

[0026] Step 1: Use ultraviolet light to irradiate the modifier to stimulate its fluorescence effect and shoot it with a camera and use image J image processing software to record the gray value of the modifier;

[0027] Step 2: put the packaged 70# matrix asphalt into an oven and heat it at 155°C for 40 minutes. When the 70# matrix asphalt is in a flowing state, take it out for use. Then weigh a certain mass of distilled water in a beaker and place it on an electric furnace for heating. Then add emulsifier and other additives to the water in sequence according to the proportion and stir it thoroughly with a glass rod. Use a thermometer to measure the temperature of the liquid in the beaker in real time and control it within 70°C. After there is no obvious sediment in the liquid, weigh the modifier according to the proportion, slowly add it to the soap solution in four times, stir it thoroughly with a glass rod, until there is no obvious agglomeration on the surface of the soap solution, turn on the colloid mill, preheat it with hot water, and when the temperature of the colloid mill reaches 65°C, slowly pour the thermochromic soap solution and the 70# matrix asphalt heated to 155°C into the colloid mill in proportion, shear at a speed of 3000rpm for 5 minutes to make modified emulsified asphalt;

[0028] Step 3: slowly pour the modified emulsified asphalt into a container and seal it to let it stand. After 0h, 24h, 72h and 120h, extract the modified emulsified asphalt solution at a depth of 5cm and 25cm from the container, respectively, and observe and record it under a fluorescence microscope;

[0029] Step 4: Filter and analyze the collected fluorescence microscopic color image, and perform segmentation processing to obtain binary images of the emulsified asphalt phase and the modifier phase, extract the modifier phase state in the binary image, and perform block operation on the binary image main matrix, divide the binary image main matrix into several binary image sub-matrices, extract the number of connected domains of the binary image main matrix and the number of modifier particles in each binary image sub-matrix, calculate the proportion of the modifier fluorescence area and the gray value to characterize the distribution of the modifier;

[0030] Step 5: Determine the storage stability of the modified emulsified asphalt by comparing the gray values ​​at the depths of 5 cm and 25 cm after standing for 0 h, 24 h, 72 h and 120 h to determine the storage stability of the modified emulsified asphalt:

[0031]

[0032] Where: S refers to the fluorescence intensity ratio;

[0033] H t is the initial gray value of modified emulsified asphalt at a depth of 5 cm;

[0034] H′ t It is the gray value of the modified emulsified asphalt at a depth of 5 cm after standing for n hours;

[0035] Hb is the initial gray value of modified emulsified asphalt at a depth of 25 cm;

[0036] H′ b It is the gray value of the modified emulsified asphalt at a depth of 25 cm after being left standing for n hours.

[0037] The relevant calculation parameters in this embodiment are shown in Table 1. The calculation shows that the fluorescence intensity ratio of the modified emulsified asphalt at 24h is 2.03, the fluorescence intensity ratio at 72h is 2.06, and the fluorescence intensity ratio at 120h is 2.10.

[0038] Table 1 Gray value data

[0039] Standing time 0h 24h 72h 120h Gray value at 5cm depth 277 290 299 312 Gray value at a depth of 25 cm 325 320 320 317

[0040] In summary, the evaluation method proposed in the present invention can evaluate the storage stability of modified emulsified asphalt more accurately, is simple and efficient to operate, and can also lay a solid foundation for the subsequent tests related to the technical performance of modified emulsified asphalt.

[0041] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. A method for evaluating the storage stability of modified emulsified asphalt, characterized in that: The following steps are involved: Step 1: Use ultraviolet light to irradiate the modifier to stimulate its fluorescence effect and shoot it with a camera and use image J image processing software to record the gray value of the modifier; Step 2: put the packaged 70# matrix asphalt into an oven and heat it at 155°C for 40 minutes. When the 70# matrix asphalt is in a flowing state, take it out for use. Then weigh a certain mass of distilled water in a beaker and place it on an electric furnace for heating. Then add emulsifier and other additives to the water in sequence according to the proportion and stir it thoroughly with a glass rod. Use a thermometer to measure the temperature of the liquid in the beaker in real time and control it within 70°C. After there is no obvious sediment in the liquid, weigh the modifier according to the proportion, slowly add it to the soap solution in four times, stir it thoroughly with a glass rod, until there is no obvious agglomeration on the surface of the soap solution, turn on the colloid mill, preheat it with hot water, and when the temperature of the colloid mill reaches 65°C, slowly pour the thermochromic soap solution and the 70# matrix asphalt heated to 155°C into the colloid mill in proportion, shear at a speed of 3000rpm for 5 minutes to make modified emulsified asphalt; Step 3: slowly pour the modified emulsified asphalt into a container and seal it to let it stand. After 0h, 24h, 72h and 120h, extract the modified emulsified asphalt solution at a depth of 5cm and 25cm from the container, respectively, and observe and record it under a fluorescence microscope; Step 4: Filter and analyze the collected fluorescence microscopic color image, and perform segmentation processing to obtain binary images of the emulsified asphalt phase and the modifier phase, extract the modifier phase state in the binary image, and perform block operation on the binary image main matrix, divide the binary image main matrix into several binary image sub-matrices, extract the number of connected domains of the binary image main matrix and the number of modifier particles in each binary image sub-matrix, calculate the proportion of the modifier fluorescence area and the gray value to characterize the distribution of the modifier; Step 5: Determine the storage stability of the modified emulsified asphalt by comparing the gray values ​​at the depths of 5 cm and 25 cm after standing for 0 h, 24 h, 72 h and 120 h to determine the storage stability of the modified emulsified asphalt: Where: S refers to the fluorescence intensity ratio; H t is the initial gray value of modified emulsified asphalt at a depth of 5 cm; H′ t It is the gray value of the modified emulsified asphalt at a depth of 5 cm after standing for n hours; H b is the initial gray value of modified emulsified asphalt at a depth of 25 cm; H′ b It is the gray value of the modified emulsified asphalt at a depth of 25 cm after being left standing for n hours.

2. According to the storage stability evaluation method of modified emulsified asphalt according to claim 1, the modifier selected in step 1 is a powdery particle, which can be excited to fluoresce under ultraviolet irradiation, is insoluble in asphalt, and can be dispersed in the emulsified asphalt.

3. According to the storage stability evaluation method of modified emulsified asphalt according to claim 1, during the filtering analysis in step 4, the color image is converted into a grayscale image to facilitate the calculation of the area ratio, the grayscale image is filtered using Wiener filters at different neighborhood levels, and the number of modifier particles in the filtered image is extracted.

4. According to the storage stability evaluation method of modified emulsified asphalt according to claim 1, the color image selected in step 4 is a square, the color and brightness of the modifier presented in the captured image are used as variables, and the final grayscale value is calculated using image J image processing software.

5. According to the storage stability evaluation method of modified emulsified asphalt according to claim 1, in step 4, the neighborhood level corresponding to when the number of particles tends to be stable is taken as the optimal neighborhood level, and the corresponding filtered image is taken as the final research object.

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