Rapid in-situ detection method for curing degree of epoxy asphalt mixture based on ultrasonic waves

Abstract

The invention discloses a rapid in-situ detection method for the curing degree of an epoxy asphalt mixture based on ultrasonic waves. The rapid in-situ detection method comprises the following steps: 1, preparing a plurality of epoxy asphalt mixture rut plate test pieces for engineering; 2, grouping the rut plate test pieces, and respectively carrying out natural curing outdoors and curing in a 60 DEG C drying oven; 3, testing the wave amplitude of the rut plate test piece based on an ultrasonic detector; 4, establishing a curing degree equation of the epoxy asphalt mixture; and 5, testing the amplitude of the pavement on site, and substituting the amplitude into the curing degree equation to calculate the curing degree alpha. According to the method, the epoxy asphalt pavement does not need to be subjected to core drilling sampling, the curing degree of the epoxy asphalt pavement can be rapidly and nondestructively measured in actual field application, and the method is suitable for large-scale popularization and application.

Description

Technical Field

[0001] The invention belongs to the technical field of road engineering detection, and in particular is a rapid in-situ detection method for the curing degree of epoxy asphalt mixture based on ultrasound. Background Art

[0002] Epoxy asphalt mixture is a high-performance road construction material that uses epoxy resin as a modifier, is added to asphalt mixture, and is supplemented with a curing agent to promote the curing process. Unlike the thermoplastic modifier used in ordinary asphalt mixtures, epoxy asphalt uses thermosetting epoxy resin as a modifier. When used, epoxy resin and curing agent can form an irreversible cross-linking network through chemical reaction, which completely changes the physical properties of epoxy asphalt, so that epoxy asphalt mixture has higher strength, better high temperature stability and fatigue resistance. Since epoxy asphalt materials are mainly modified by the curing reaction of epoxy resin, the implementation process is significantly different from that of ordinary asphalt and modified asphalt. Epoxy asphalt mixtures need to go through certain curing conditions and curing time before they can finally cure. In addition, during the curing process, the mechanical behavior of epoxy asphalt mixtures is closely related to their degree of curing, which is mainly affected by factors such as temperature and time. Opening traffic too early will lead to insufficient mechanical strength and cause early damage to the road surface, which will have an adverse effect on the final performance of epoxy asphalt mixtures. Therefore, determining the curing degree of epoxy asphalt mixture is of great engineering significance for on-site pavement opening.

[0003] Studying the curing of epoxy asphalt mixtures is essentially similar to studying the curing of epoxy resins. Currently, the evaluation of epoxy resin curing includes measuring the concentration of consumed and generated functional groups during the curing reaction (differential scanning calorimeter (DSC)) and testing the influence of the network structure of the cured product on the physical and mechanical properties (dynamic mechanical properties DMA). These test methods are typical indirect research methods. Although the results are not very intuitive, they are simple in test and very suitable for mixed structures with other substances besides epoxy asphalt. The evaluation of the curing degree of epoxy asphalt mixtures is also characterized by the mechanical strength of the cured product, such as Marshall strength. However, this type of technology has cumbersome procedures such as on-site sampling, which has an adverse effect on the integrity of the pavement structure, especially when sampling steel bridge decks, there may be a risk of damaging the steel plate. Therefore, a non-destructive, in-situ method for testing the curing degree of epoxy asphalt is needed. In recent years, many foreign experts have used ultrasound to monitor the curing process of polymers online. For example, experts from South Korea, Australia and other countries have conducted ultrasonic monitoring tests on epoxy resins with titanium, silicon, aluminum oxide and other fillers. Lionetto et al. in Italy used ultrasound to study the curing behavior of unsaturated polyester resins. The results show that the speed of sound and amplitude will change significantly during the curing process of the resin, and the change pattern of the amplitude is consistent with the test of the curing degree of epoxy resin using DSC and DMA methods. Summary of the invention

[0004] The purpose of the invention is to provide a rapid in-situ detection method for the curing degree of epoxy asphalt mixture based on ultrasound. The method is simple to operate and has good repeatability, and can achieve rapid and in-situ measurement of the curing degree of epoxy asphalt mixture.

[0005] Technical solution: A rapid in-situ detection method for curing degree of epoxy asphalt mixture based on ultrasound, comprising the following steps:

[0006] Step 1: Prepare several rutting plate specimens and Marshall specimens with the aggregate, asphalt, epoxy system, gradation and asphalt-stone ratio selected for the project;

[0007] Step 2: Divide a number of wheel rutting specimens and Marshall specimens into two groups, with each group having no less than 3 wheel rutting specimens and Marshall specimens; the first group of specimens are placed outdoors for natural curing, and the second group of specimens are placed in a 60°C oven for curing for 4 days;

[0008] Step 3: Use an ultrasonic detector to detect the amplitude of the two groups of test pieces by ultrasonic rebound method;

[0009] Step 4: Take the mean amplitude AM of the rutting specimens in group 1 that have been cured for 0 days 0 and the mean amplitude AM of the Marshall specimens in group 2 Final , establish the curing degree equation of epoxy asphalt mixture:

[0010]

[0011] Among them, AM i is the mean amplitude of the i-day health regimen, AM 0 is the mean amplitude on day 0 of the regimen, AM Final is the mean amplitude of the i-day regimen;

[0012] Step 5: Test the amplitude of the epoxy asphalt pavement to be tested on site, and substitute it into the curing degree equation in step 4 to obtain the curing degree α of the epoxy asphalt mixture on site.

[0013] Among them, preferably, the aggregate in step 1 is a mineral material that has been demonstrated to be used in epoxy asphalt pavement, including but not limited to basalt, limestone, and diabase; the asphalt is an asphalt binder that has been demonstrated to be used in epoxy asphalt pavement, including but not limited to 70# asphalt, 90# asphalt and SBS modified asphalt; the epoxy system is an epoxy system that has been demonstrated to be used in epoxy asphalt pavement, including but not limited to domestic epoxy, Japanese epoxy and American epoxy systems; the gradation includes the dense gradation and discontinuous gradation recommended in JTGF40-2004, but does not include open gradation.

[0014] Among them, preferably, the number of rutting plate specimens prepared in step 1 should not be less than 10 pieces, and the rutting plate specimens should be formed using the method in JTGE20-2011, with the length and width of the dimensions not less than 10 cm and the thickness between 2 and 10 cm.

[0015] Among them, preferably, the ultrasonic detector described in step 3 is a non-metallic ultrasonic detector, and the distance between the two detectors during the test should not be less than 3 cm; the amplitude of the rutting plate specimen is tested no less than 5 times; before testing the amplitude of the rutting specimen, a filling agent should be used to smooth the surface potholes, and the filling agent includes but is not limited to vaseline; the temperature for testing the amplitude of the rutting plate specimen should be between 10 and 40°C.

[0016] Preferably, the temperature when detecting the amplitude of the on-site road surface in step 5 should be detected and recorded using a device with a temperature testing function. More preferably, an infrared imager is used to scan the surface and the average value is taken as the final result.

[0017] Beneficial effects: The scheme of the present invention is easy to operate and has good repeatability, and can realize rapid and in-situ measurement of the curing degree of epoxy asphalt mixture. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a waveform detection diagram of the ultrasonic rebound method of the present invention.

[0019] Figure 2It is a process diagram of testing the amplitude of epoxy asphalt mixture rutting plate by the ZBL-U520 non-metallic ultrasonic detector of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention is clearly and completely described. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Example

[0022] A rapid in-situ detection method for curing degree of epoxy asphalt mixture based on ultrasound is carried out in the following steps:

[0023] Step 1: Based on basalt aggregate, 70# matrix asphalt, self-developed epoxy system, AC-13 grading and 6.2% asphalt-stone ratio, rutting plate specimens and Marshall specimens were molded, with the molding quantity of 10 and 30 respectively;

[0024] Step 2, divide the 10 and 30 Marshall rutting specimens into 2 groups, 5 rutting specimens in each group and 5 Marshall specimens in each group, one group is placed outdoors for natural curing, and the other group of specimens is placed in a 60°C oven for curing for 4 days;

[0025] Step 3, using an ultrasonic detector, the ultrasonic rebound method is used to detect the amplitude of the rutting plate specimens that have been cured naturally for 0-8 days (2 days apart) and cured in a 60°C oven for 4 days (see Table 1). Similarly, the amplitude of the Marshall specimen is tested by the ultrasonic rebound method (see Table 2), and the Marshall stability of the specimen is tested after the amplitude test is completed (see Table 3). It can be seen from Tables 1 and 2 that the mean values ​​of the amplitude results of the rutting and Marshall specimen tests are similar, indicating that the ultrasonic rebound method for testing the curing degree of epoxy asphalt mixture has nothing to do with the shape of the specimen, and has good repeatability under the same curing conditions. In addition, the curing degree predicted by the acoustic wave test results is close to the curing degree predicted by the Marshall stability, with an error of less than 10%.

[0026] Table 1 Amplitude test results of rutting specimens with different curing times

[0027]

[0028] Table 2 Amplitude test results of Marshall specimens at different curing times

[0029]

[0030]

[0031] Table 3 Average amplitude and average stability test results of Marshall specimens at different curing times

[0032]

[0033] Step 4: Establish the curing degree equation of epoxy asphalt mixture based on the amplitude mean value AM0 of curing for 0 days and the amplitude mean value AMfinal of Marshall specimens cured in a 60°C oven for 4 days:

[0034]

[0035] Among them, AMi is the mean amplitude of the i-day regimen, AM0 is the mean amplitude of the 0-day regimen, and AMfinal is the mean amplitude of the i-day regimen;

[0036] Step 5, test the amplitude of the epoxy asphalt pavement to be tested on site (see Table 4), substitute it into the curing degree equation in step 4 to calculate the curing degree of the epoxy asphalt mixture on site α=74.2%, which meets the requirements for open traffic.

[0037] Table 4 Field test results of epoxy asphalt pavement amplitude

[0038]

[0039]

[0040] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes in form and details may be made without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A rapid in-situ detection method for curing degree of epoxy asphalt mixture based on ultrasound, characterized in that: The following steps are involved: Step 1: Prepare several rutting plate specimens and Marshall specimens with the aggregate, asphalt, epoxy system, gradation and asphalt-stone ratio selected for the project; Step 2: Divide a number of rutting specimens and Marshall specimens into two groups, with each group having no less than 3 rutting plates and Marshall specimens; the first group of specimens are placed outdoors for natural curing, and the second group of specimens are placed in a 60°C oven for curing for 4 days; Step 3: Use an ultrasonic detector to detect the amplitude of the two groups of test pieces by ultrasonic rebound method; Step 4: Take the mean amplitude value AM0 of the rutting plate specimens cured for 0 days in group 1 and the mean amplitude value AM of the Marshall specimens in group 2 Final , establish the curing degree equation of epoxy asphalt mixture: Among them, AM i is the mean amplitude of the i-th day of health care, AM0 is the mean amplitude of the 0-th day of health care, AM Final is the mean amplitude of the i-day regimen; Step 5: Test the amplitude of the epoxy asphalt pavement to be tested on site, and substitute it into the curing degree equation in step 4 to obtain the curing degree α of the epoxy asphalt mixture on site.

2. The rapid in-situ detection method of curing degree of epoxy asphalt mixture based on ultrasound according to claim 1 is characterized in that: The aggregate in step 1 is a mineral material that has been demonstrated to be applicable to epoxy asphalt pavement, including but not limited to basalt, limestone, and diabase; the asphalt is an asphalt binder that has been demonstrated to be applicable to epoxy asphalt pavement, including but not limited to 70# asphalt, 90# asphalt, and SBS modified asphalt; the epoxy system is an epoxy system that has been demonstrated to be applicable to epoxy asphalt pavement, including but not limited to domestic epoxy, Japanese epoxy, and American epoxy systems; the gradation includes the dense gradation and discontinuous gradation recommended in JTG F40-2004, but does not include open gradation.

3. The rapid in-situ detection method of curing degree of epoxy asphalt mixture based on ultrasound according to claim 1 is characterized in that: There should be no less than 10 rutting plate specimens prepared in step 1. The rutting plate specimens should be formed using the method in JTG E20-2011. The length and width of the rutting plate specimens should not be less than 10 cm, and the thickness should be between 2 and 10 cm.

4. The rapid in-situ detection method of curing degree of epoxy asphalt mixture based on ultrasound according to claim 1 is characterized in that: The ultrasonic detector described in step 3 is a non-metallic ultrasonic detector. During the test, the distance between the two detectors should not be less than 3 cm. The amplitude of the rutting plate specimen should be tested no less than 5 times. Before testing the amplitude of the rutting specimen, a filler should be used to smooth the surface holes. The filler includes but is not limited to vaseline. The temperature for testing the amplitude of the rutting plate specimen should be between 10 and 40°C.

5. The rapid in-situ detection method of curing degree of epoxy asphalt mixture based on ultrasound according to claim 1 is characterized in that: The temperature when detecting the amplitude of the on-site road surface in step 5 should be detected and recorded using equipment with temperature testing function.

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