Testing device and method for testing mesoscopic cracks of asphalt pavement material

Abstract

The invention provides a testing device for testing mesoscopic cracks of an asphalt pavement material. The testing device comprises a sample barrel; a sealing cover; the communicating pipe is vertically inserted into the sealing cover, the lower end of the communicating pipe is positioned below the liquid surface of the sample barrel, and a plurality of scales are arranged on the peripheral side of the communicating pipe; an output port of the pressurizing equipment is mutually inserted into the sealing cover and is communicated with the interior of the sample barrel, and the output port of the pressurizing equipment is hermetically connected with the inserting part of the sealing cover; the device further comprises a balance. According to the technical scheme, aiming at the tiny cracks, the width of the tiny cracks is smaller than 0.1 mm, and other media are difficult to enter the tiny cracks if external pressure is not intervened, the water is pressed into the cracks of the core sample in a pressure applying mode, and the volume of the tiny cracks can be calculated through the liquid level change; the device is simple in overall structure, and is matched with the precise scale of the communicating pipe and the precise measurement of the balance, so that the precision and the accuracy of the overall test measurement are guaranteed.

Description

Technical Field

[0001] The present invention generally relates to the field of asphalt testing equipment, and in particular to a testing device and method for testing mesoscopic cracks of asphalt pavement materials. Background Art

[0002] Mesoscopic cracks in asphalt refer to those cracks that are between the microscopic and macroscopic scales. Their width is usually small, generally between tens of micrometers and a few millimeters. Compared with macroscopic cracks that are visible to the naked eye, mesoscopic cracks require the aid of certain tools, such as magnifying glasses, microscopes, etc. to observe. From the appearance, mesoscopic cracks may appear as tiny cracks on the surface of asphalt or tiny cracks inside.

[0003] Mesoscopic cracks have three main effects on asphalt: the durability of asphalt, the waterproof performance of asphalt, and the appearance and performance of asphalt pavement. All acceptance measurements of asphalt mesoscopic cracks are extremely important. Common methods for measuring asphalt mesoscopic cracks include: laser sensor detection, radar detection, digital image analysis technology, ultrasonic detection, etc. Existing instruments are used to test pavement surface cracks on the road site, and they all measure the number, length, width, and depth of cracks from the surface, and then classify the cracks based on these measured crack sizes, especially the width size, and perform corresponding repairs.

[0004] However, the common measurement methods have the following shortcomings: on the one hand, they cannot test the crack conditions within the overall thickness of the structural layer of the asphalt; on the other hand, surface testing is more accurate for crack sealing and width testing, but it is difficult to accurately obtain depth testing, and it is difficult to obtain the asphalt volume indicator. Summary of the invention

[0005] According to the present invention, in view of the problems existing in the above-mentioned prior art, a testing device for testing the micro-cracks of asphalt pavement materials is provided, which is characterized by comprising: a sample barrel for containing liquid and drilled pavement core samples; a sealing cover, which is arranged on the top of the sample barrel; a connecting pipe, which is vertically inserted with the sealing cover, and its lower end is located below the liquid surface of the sample barrel, and a plurality of scales are arranged on the circumference of the connecting pipe along its length direction, and the connecting pipe is sealed and connected with the plug-in part of the sealing cover; a pressurizing device, whose output port is mutually plugged with the sealing cover and communicated with the inside of the sample barrel, and the output port of the pressurizing device is sealed and connected with the plug-in part of the sealing cover; and also includes a balance. By having the above-mentioned technical features, the core sample is immersed in liquid, and pressure is applied, so that the liquid is pressed into the tiny holes of the core sample, and the volume of the micro-cracks can be calculated by the change of the liquid level, so as to make a comprehensive judgment on the micro-cracks of the overall structure of the core sample.

[0006] In some embodiments, it also includes: an air valve, one end of which is sealed and connected to the sealing cover and communicated with the inside of the sample barrel; the other end of the air valve is used to be sealed and connected to the output port of the pressurizing device. Therefore, the setting of the air valve can achieve pressure maintenance and pressure stabilization on the one hand, reducing the occurrence of air leakage; on the other hand, by cooperating with the pressurizing device, it can reduce the occurrence of air leakage during pressurization.

[0007] In some embodiments, the pressurizing device is a syringe, and the output port of the syringe is sealed and plugged into the air inlet port of the air valve. Therefore, the syringe has a simple structure, low cost, and is easy to carry, which simplifies the difficulty of experimental operation. It can not only perform gas injection operations, but also liquid injection operations, and its own structure can replace the function of the funnel.

[0008] In some embodiments, a supporting seal is provided between the connecting tube and the sealing cover, and the supporting seal includes a sealing pressure plate, on which a through hole is provided to match the connecting tube, and the inner wall of the through hole is sealed and connected to the connecting tube; a threaded tube is fixed to the bottom of the sealing pressure plate, and the inner wall diameter of the threaded tube is larger than the diameter of the through hole, and the through hole is located within the range of the threaded tube; a supporting tube is fixed to the top of the sealing pressure plate and is coaxial with the through hole, and the inner wall diameter of the supporting tube matches the connecting tube; and a thread groove is provided on the sealing cover on the side of the connecting tube plug-in to match the thread of the threaded tube. Thus, the supporting seal can play a sealing role at the connection between the connecting tube and the sealing cover, and is not prone to air leakage; it can also increase the contact area with the connecting tube, improve the stability of the connecting tube support, and ensure that the connecting tube is always in a vertical state, thereby improving the test accuracy.

[0009] In some embodiments, the diameter of the inner wall of the end of the support tube connected to the sealing plate gradually increases to the inner wall of the other end of the support tube. Therefore, when the connecting tube is subjected to stress, the gap between the support tube and the connecting tube provides a deformation space for the connecting tube, thereby ensuring the safety of the connecting tube in use.

[0010] In some embodiments, an abutting sealing ring is disposed inside the support pipe port. Thus, the abutting sealing ring abuts against the outer wall of the connecting pipe, which not only plays a sealing role, but also ensures the vertical arrangement of the connecting pipe. When the connecting pipe is subjected to external stress, the abutting sealing ring can also increase the deformation space of the connecting pipe by deforming itself, thereby ensuring the safety of the connecting pipe itself.

[0011] A method for testing mesoscopic cracks of asphalt pavement materials, comprising:

[0012] Sampling: Drill core samples from the road surface to be tested;

[0013] Dust removal: Use cleaning tools to remove dust from the core sample and remove floating dust on the surface of the core sample;

[0014] Weigh the core, use a balance to weigh the mass of the core sample as m, and slowly put the core sample into the sample bucket;

[0015] Fill water, slowly inject clean water into the sample barrel until the water level exceeds the core sample height, and record the water level as H;

[0016] Closing the cover, placing the sealing cover on the port of the sample barrel;

[0017] Put it in place, and plug the connecting pipe into the sealing cover, so that the lower end of the connecting pipe is below the horizontal plane, and the 0 scale on the side of the connecting pipe is flush with the horizontal plane, connect the supporting seal to keep the connecting pipe vertical; then plug the output port of the syringe into the input port of the air valve;

[0018] Adjust the initial height, and reciprocate the syringe by controlling the air valve to pressurize the inside of the sample barrel, and accurately adjust the height change of the liquid level in the connecting tube until the liquid level in the connecting tube rises to the height h1, close the air valve, and remove the syringe;

[0019] Second weighing: put the device without the syringe on a balance and weigh the whole device with an accuracy of 0.002g, and record the mass at this time as M1;

[0020] For pressurized measurement, reconnect the syringe to the air inlet of the air valve, open the air valve, and pressurize the sample barrel again through the cooperation of the syringe and the air valve, so that the liquid level inside the connecting tube rises by at least 100 cm, close the air valve, and record the liquid level height of the connecting tube at this time as h2;

[0021] One-time error weighing, using a balance to weigh the entire mass of the device excluding the syringe as M2;

[0022] Let it stand for 2-3 hours, record the liquid level in the connecting pipe, and record the liquid level as h3;

[0023] Secondary error weighing, using a balance to weigh the entire mass of the device excluding the syringe is M3, and the microscopic crack volume of the sample can be calculated through the inner wall diameter of the connecting tube (3), h3, and h2 data.

[0024] In some embodiments, the following steps may be performed after the pressure measurement:

[0025] Take out the core sample, take it out of the sample barrel, and air-dry it with normal temperature air;

[0026] Apply load to the core sample, place the core sample on a plane according to the drilling state, and use a rubber hammer to hammer the core sample at a fixed frequency from the top of the core sample to simulate the vehicle load. The number of hammering times is 5-10 times;

[0027] Weigh the core sample again, weigh the core sample after hammering, and take the mass of the core sample as m0. Then collect the particle residue dropped during the hammering process and weigh it together with the core sample. The weighed weight is (m0);

[0028] Reset the test conditions so that the water level in the sample bucket remains at height H and the connecting pipe returns to its original position;

[0029] Put in the core sample slowly, seal the sealing cover with the port of the sample barrel, and adjust the liquid level of the connecting tube to h again through the syringe, and remove the syringe;

[0030] Weigh three times, place the device without the syringe on a balance and weigh the whole device with an accuracy of 0.002g, and record the mass at this time as M load ;

[0031] Synchronize the mass, insert the syringe, and slowly inject clean water into the sample barrel until M load =M1, let it stand until the water surface is still, and read the water level of the connecting pipe as h1 load , then |h1 load -h1| is the effect of the initial load on the material volume;

[0032] Secondary pressurization test: Use a syringe to push air into the sample barrel until the liquid level in the connecting tube reaches h2, and then close the air valve;

[0033] Weigh four times, using a balance to weigh the entire mass of the device excluding the syringe as M2;

[0034] Let it stand for 2-3 hours and record the liquid level in the connecting pipe as h3 load ;

[0035] Weigh five times, using a balance to weigh the entire mass of the device excluding the syringe as M3, then |h2-h3 load | is the volume of micro cracks in the core sample that cannot be penetrated by water under normal pressure after the core sample is subjected to simulated load.

[0036] In some embodiments, the following steps may be performed after the pressure measurement:

[0037] Take out the core sample, take it out of the sample barrel, air-dry it with normal temperature air, isolate and seal the sample, put it in a refrigerator, set the specific temperature according to the lowest temperature in the area plus or minus ten degrees, and freeze it in a low temperature environment for 24 days, then take out the core sample;

[0038] Weigh the core sample again, weigh the frozen core sample, and take the mass of the core sample as m0. Then collect the particle residues that fall during the freezing process and weigh them together with the core sample. The weighed weight is (m0);

[0039] Reset the test conditions so that the water level in the sample bucket remains at height H and the connecting pipe returns to its original position;

[0040] Put in the core sample slowly, seal the sealing cover with the port of the sample barrel, and adjust the liquid level of the connecting tube to h again through the syringe, and remove the syringe;

[0041] Weigh three times, put the device without the syringe on the balance and weigh the whole device with an accuracy of 0.002g, and record the mass at this time as M ice ;

[0042] Synchronize the quality and drain the water through the drain valve at the bottom of the sample barrel until M ice =M1, let it stand until the water surface is still, and read the water level of the connecting pipe as h1 ice , then |h1 ice -h1| is the effect of freezing on the volume of the material;

[0043] Secondary pressurization test: Use a syringe to push air into the sample barrel until the liquid level in the connecting tube reaches h2, and then close the air valve;

[0044] Weigh four times, using a balance to weigh the entire mass of the device excluding the syringe as M2;

[0045] Let it stand for 2-3 hours and record the liquid level in the connecting pipe as h3 ice ;

[0046] Weigh five times, using a balance to weigh the entire mass of the device excluding the syringe as M3, then |h2-h3 ice | is the volume of micro cracks that cannot be penetrated by water under normal pressure in the core sample after partial freezing.

[0047] In some embodiments, the following steps may be performed after the pressure measurement:

[0048] Take out the core sample, take it out of the sample barrel, air dry it with normal temperature air, and then put it into the oven for heating. The specific temperature is set according to the highest temperature in the area plus or minus ten degrees. Keep it warm for 24 days and take out the core sample;

[0049] Weigh the core sample again, weigh the heated core sample, and take the mass of the core sample as m0. Then collect the particle residue that falls during the heating process and weigh it together with the core sample. The weighed weight is (m0);

[0050] Reset the test conditions so that the water level in the sample barrel (1) remains at height H and the connecting pipe (3) returns to its original position;

[0051] Put in the core sample slowly, seal the sealing cover with the port of the sample barrel, and adjust the liquid level of the connecting tube to h again through the syringe, and remove the syringe;

[0052] Weigh three times, put the device without the syringe on the balance and weigh the whole device with an accuracy of 0.002g, and record the mass at this time as M hot ;

[0053] Synchronize the mass, insert the syringe, and slowly inject clean water into the sample barrel until M hot =M1, let it stand until the water surface is still, and read the water level of the connecting pipe as h1 hot , then |h1 hot -h1| is the effect of high temperature on the volume of the material;

[0054] Secondary pressurization test: Use a syringe to push air into the sample barrel until the liquid level in the connecting tube reaches h2, and then close the air valve;

[0055] Weigh four times, using a balance to weigh the entire mass of the device excluding the syringe as M2;

[0056] Let it stand for 2-3 hours and record the liquid level in the connecting pipe (3) as h3 hot ;

[0057] Weigh five times, using a balance to weigh the entire mass of the device excluding the syringe as M3, then |h2-h3 hot | is the volume of micro cracks in the core sample that cannot be penetrated by water under high temperature and normal pressure.

[0058] Therefore, the above test steps subject the core samples to room temperature, load state, low temperature state, and high temperature state to simulate different actual working conditions, so as to measure the impact of different working conditions on the mesoscopic cracks of asphalt materials, and the mesoscopic cracks in the overall structure of the core samples can be evaluated by immersion and pressurization, thereby improving the accuracy of the test measurement.

[0059] It should be understood that the contents described in the summary of the invention are not intended to limit the key or important features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 A schematic diagram showing the overall structure of a testing device for testing mesoscopic cracks in asphalt pavement materials according to an embodiment of the present invention is shown;

[0061] Figure 2 A schematic diagram showing the overall structure of a support seal in a testing device for testing mesoscopic cracks in asphalt pavement materials according to an embodiment of the present invention is shown;

[0062] Figure 3 A schematic diagram of a local area of ​​a sealing cover in a testing device for testing mesoscopic cracks in asphalt pavement materials according to an embodiment of the present invention is shown;

[0063] Figure 4 A cross-sectional view showing a support seal in a testing device for testing mesoscopic cracks in asphalt pavement materials according to an embodiment of the present invention;

[0064] Figure 5 A flow chart of a method for testing mesoscopic cracks in asphalt pavement materials according to an embodiment of the present invention is shown;

[0065] Figure 6 A flow chart showing the effect of load on micro cracks inside a core sample in a method for testing micro cracks in asphalt pavement materials according to an embodiment of the present invention is shown;

[0066] Figure 7 A flow chart showing the effect of freezing on micro cracks inside a core sample in a method for testing micro cracks in asphalt pavement materials according to an embodiment of the present invention is shown;

[0067] Figure 8 A flow chart showing the effect of high temperature on micro cracks inside a core sample in a method for testing micro cracks in asphalt pavement materials according to an embodiment of the present invention is shown.

[0068] Explanation of symbols

[0069] 1. Sample barrel; 2. Sealing cover; 21. Threaded groove; 3. Connecting pipe; 4. Support seal; 41. Sealing pressure plate; 42. Threaded pipe; 43. Support pipe; 44. Abutting sealing ring; 5. Syringe; 6. Air valve; 7. Drain valve; 8. Balance. DETAILED DESCRIPTION

[0070] Hereinafter, preferred embodiments (or implementation modes) of the present invention will be described in detail with reference to the accompanying drawings.

[0071] A testing device for testing microscopic cracks of asphalt pavement materials comprises a sample barrel 1 at the bottom, a sealing cover 2 sealed with the sample barrel 1, a connecting pipe 3 sealed and plugged with the sealing cover 2, a pressurizing device inserted on the sealing cover 2 for applying pressure to the sample barrel 1, and a precision weighing balance 8. The device immerses a pavement core sample in the sample barrel 1, pressurizes the sealed sample barrel 1 through the pressurizing device, and within a certain period of time, through the measurement of the liquid by the precise scale lines on the connecting pipe 3, in combination with the density of the liquid, the microscopic cracks of the pavement core sample can be accurately calculated. The device is not only simple in structure, but also improves the accuracy of the overall test through the cooperation of the precise scale of the connecting pipe and the high-precision balance.

[0072] refer to Figure 1-Figure 8The present invention will be used to describe a testing device and method for testing micro-cracks in asphalt pavement materials.

[0073] Figure 1 The overall structure schematic diagram of a testing device for testing micro-cracks in asphalt pavement materials according to an embodiment of the present invention is shown. Figure 1 As shown, a testing device for testing micro-cracks of asphalt pavement materials provided in this embodiment includes a sample barrel 1, a sealing cover 2, a connecting pipe 3, a pressurizing device and a balance 8.

[0074] The sample barrel 1 has a port at the top, and the internal space can accommodate the vertical or horizontal placement of the core sample, and after the core sample is placed, it will not affect the cover setting and sealing connection of the sealing cover 2. The sample barrel 1 can be a barrel body made of transparent material, so that personnel can observe the placement status of the core sample inside the sample barrel 1, the liquid level and the liquid level; and the outer wall of the sample barrel 1 is provided with scale lines along its height direction, so that personnel can record the initial water filling height and the test liquid level record. The bottom of the sample barrel 1 is also connected to a drain valve 7 to cooperate with the drainage operation.

[0075] In some embodiments, there can be at least two scale lines arranged on the side of the sample barrel 1, and they are arranged relatively on the side of the sample barrel 1, so that when the sample barrel 1 is filled with liquid, the scale lines on both sides can be observed to ensure that the liquid is in a horizontal state, thereby ensuring the accuracy of data measurement.

[0076] The sealing cover 2 is arranged on the upper end of the sample barrel 1 , and a sealing material such as a rubber ring is arranged in the contact area between the sealing cover 2 and the sample barrel 1 , thereby ensuring the tightness of the connection between the sealing cover 2 and the sample barrel 1 .

[0077] The connecting tube 3 is a long straight transparent tube, and its outer surface is provided with multiple scale lines at intervals along its length direction to facilitate recording the height changes of the liquid level. And the smallest scale of the scale line is 0.005ml to ensure the accuracy of the final test data measurement. The length of the connecting tube 3 is set to 1.5m. For fine cracks, 0.1MPa is the minimum pressure value for water to enter the crack of about 0.1mm, that is, the height of the thin glass tube is at least 1m higher to meet the rise of the water level. During the test, the connecting tube 3 is vertically plugged with the sealing cover 2, and the lower end of the connecting tube 3 is immersed below the liquid level in the sample barrel 1. The zero scale of the connecting tube 3 is flush with the liquid surface to facilitate the accuracy of subsequent data reading. In order to avoid interference between the position of the connecting tube 3 and the position of the core sample, the connecting tube 3 can be close to the edge area of ​​the sealing cover 2, so that the connecting tube 3 is close to the inner wall area of ​​the barrel body after being inserted into the sample barrel 1, thereby improving the safety of the installation state of the connecting tube 3.

[0078] The balance 8 can be a high-precision balance, and the sensitivity of the balance is not greater than 0.005g. During the test, the balance 8 can be used to weigh the entire weight of the core sample, or the balance 8 can be used to balance the data before and after the test, so as to achieve the effect of controlling the variables.

[0079] Figure 2 The overall structural schematic diagram of the support seal 4 in a test device for testing microscopic cracks of asphalt pavement materials according to an embodiment of the present invention is shown. The connecting pipe 3 and the sealing cover 2 are connected to each other through the support seal 4, which not only supports the connecting pipe 3, but also helps to increase the sealing between the connecting pipe 3 and the sealing cover 2, thereby improving the efficiency of stabilizing and maintaining pressure, and further improving the accuracy of the test.

[0080] The supporting seal 4 includes a sealing plate 41, which can be a circular sheet, and a circular through hole is coaxially provided in the middle thereof for inserting the connecting tube 3. The diameter of the through hole can be the same as the diameter of the outer wall of the connecting tube 3, or can be slightly larger than the diameter of the outer wall of the connecting tube 3, so as to add sealing material between the inner wall of the through hole and the connecting tube 3. A threaded tube 42 is coaxially provided on the side of the sealing plate 41 facing the sample barrel 1, and one end of the threaded tube 42 is fixedly connected to the sealing plate 41. Figure 3 A schematic diagram of a local area of ​​a sealing cover 2 in a testing device for testing microscopic cracks in asphalt pavement materials according to an embodiment of the present invention is shown, with reference to Figure 3 As shown, an annular thread groove 21 is provided around the plug-in part of the upper surface of the sealing cover 2 and the connecting pipe 3, so that the connecting pipe 3 and the sealing cover 2 are connected to each other through the threaded connection of the threaded pipe 42 and the thread groove 21. Moreover, the length of the threaded pipe 42 is the same as the depth of the thread groove 21, so that when the threaded pipe 42 is screwed into the bottom of the thread groove 21, the sealing plate 41 is tightly attached to the upper surface of the sealing cover 2. In order to improve the sealing performance between the sealing plate 41 and the sealing cover 2, the sealing material can also be sandwiched in the fitting area of ​​the sealing plate 41 and the sealing cover 2 to fill the connection gap between the sealing plate 41 and the sealing cover 2.

[0081] A support tube 43 is also provided on the side of the sealing pressing piece away from the threaded tube 42, and one end of the support tube 43 is coaxially fixed to the sealing pressing piece, so that when the connecting tube 3 and the sealing pressing piece are inserted into each other, the inner wall of the support tube 43 and the outer wall of the connecting tube 3 abut against each other, thereby increasing the contact area between the connecting tube 3 and the supporting seal 4, which not only ensures the stability of the supporting of the connecting tube 3, but also increases the supporting strength of the connecting tube 3, and the support tube 43 increases the contact area with the hand, which is convenient for personnel to screw the supporting seal 4 through the support tube 43, thereby improving the tightness of the threaded tube 42 and the threaded groove 21.

[0082] Figure 4A cross-sectional view of a support seal 4 in a testing device for testing micro-cracks of asphalt pavement materials according to an embodiment of the present invention is shown. Figure 4 As shown, in some embodiments, the inner diameter of the support tube 43 gradually increases from the end close to the sealing pressing plate to the other end, and an annular abutting sealing ring 44 is coaxially fixed on the inner wall of the port of the support tube 43. When the connecting tube 3 is inserted into the supporting tube 43, the annular area of ​​the abutting sealing ring 44 abuts against the outer wall of the connecting tube 3, which not only plays a sealing role, but also assists in supporting the connecting tube 3 and ensures the vertical state of the connecting tube 3. Even if the connecting tube 3 is subjected to external stress, the extra space on the inner wall of the supporting tube 43 helps to release the deformation of the connecting tube 3, which has ensured the safety of the use of the connecting tube 3, and the abutting sealing ring 44 can also assist in supporting the connecting tube 3 through its own elastic deformation, ensuring the return and sealing of the connecting tube 3.

[0083] refer to Figure 1 The pressurizing device can be a syringe 5. The syringe is preferably made of metal with a large capacity and has scales on its side. After being sealed with the sealing cover 2, it can not only pressurize the sample barrel 1, but also perform water injection. Its main body is similar to the funnel structure, which reduces the test error caused by opening the sealing cover 2 during the water injection operation. In addition, an air valve 6 is provided between the syringe 5 and the sealing cover 2. The air valve 6 is a manual air valve 6, and its air outlet port is sealed with the sealing cover 2 and is interconnected with the inside of the sample barrel 1; the air inlet end of the air valve 6 cooperates with the port of the syringe 5, so that the sample barrel 1 can be conveniently injected with water or gas through the mutual insertion of the syringe 5 and the air valve 6, and the opening and closing of the air valve 6 are coordinated to reduce the occurrence of air leakage and improve the accuracy of the test.

[0084] Figure 5 A flow chart of a method for testing microscopic cracks in asphalt pavement materials according to an embodiment of the present invention is shown. Figure 5 , a method for testing mesoscopic cracks in asphalt asphalt pavement materials, the specific steps are as follows:

[0085] S1: Sampling: Drill core samples on the road surface to be tested. The core samples can be sampled multiple times to reduce errors in subsequent tests and improve test accuracy.

[0086] S2: Dust removal: Use cleaning tools, such as a brush, to sweep and dust the outer circumference of the core sample to remove floating dust on the surface of the core sample and reduce the impact of floating dust on the filling of cracks on the surface of the core sample.

[0087] S3: Weigh the core, use the balance 8 to weigh the mass of the core sample as m, and slowly put the core sample into the sample barrel 1 to avoid the core sample being damaged and affecting the volume or mass, which ultimately affects the final test accuracy.

[0088] S4: Filling water. Slowly inject clean water into the sample barrel 1 to make the water level exceed the core sample height and immerse the core sample in the water. After the water level is calm, record the initial liquid level in the sample barrel 1 as H. During the process of injecting clean water, try to avoid splashing of liquid. After water injection, wipe off the splashed water droplets on the inner and outer walls of the sample barrel 1 to reduce the test error caused by subsequent mass weighing.

[0089] S5: Close the cover and place the sealing cover 2 at the port of the sample barrel 1.

[0090] S6: Put the connecting tube 3 into position and insert it into the sealing cover 2, so that the lower end of the connecting tube 3 is below the horizontal plane, and the zero scale on the side of the connecting tube 3 is flush with the horizontal plane, install the supporting seal 4 to keep the connecting tube 3 in a vertical position, and then insert the output port of the syringe 5 into the input port of the air valve 6.

[0091] S7: Adjust the initial height, and pressurize the sample barrel 1 through the cooperation between the syringe 5 and the air valve 6, and accurately adjust the height change of the liquid level in the connecting tube 3 until the liquid level in the connecting tube 3 rises to the height h1, close the air valve 6, and remove the syringe 5.

[0092] S8: Second weighing, put the device without the syringe 5 on the balance 8 for overall weighing with an accuracy of 0.002g, and record the mass at this time as M1; during the moving process, try to keep the movement slow to reduce the shaking of the liquid level and the displacement of the connecting tube 3 to avoid subsequent test errors.

[0093] S9: Pressurized measurement, connect the syringe 5 to the air inlet end of the air valve 6 again, open the air valve 6, and pressurize the sample barrel 1 again through the cooperation of the syringe 5 and the air valve 6, so that the liquid level height inside the connecting tube 3 rises by at least 100 cm, close the air valve 6, and record the liquid level height of the connecting tube 3 at this time as h2.

[0094] S10: Primary error weighing: using a balance 8 to weigh the entire mass of the device excluding the syringe 5 as M2.

[0095] S11: Let stand for 2-3 hours, record the liquid level height of connecting pipe 3, and record the liquid level height as h3.

[0096] S12: Second error weighing, using the balance 8 to weigh the mass of the entire device excluding the syringe 5 as M3, then h2-h3 is the volume of the micro cracks that cannot be entered by water under normal pressure of the core sample, and the volume of the micro cracks of the sample can also be calculated by the inner wall diameter of the connecting tube 3, h3, and h2 data. The comparison of M2 and M3 is helpful to determine whether there is leakage during the static process, and to prevent the test error caused by the reduction of the mass of the sealed gas inside the container due to leakage. If leakage occurs, the test needs to be repeated.

[0097] Figure 6 A flow chart showing the effect of load on micro cracks in a core sample according to a method for testing micro cracks in asphalt pavement materials according to an embodiment of the present invention is shown. Figure 6 As shown, in some embodiments, if the influence of load on micro cracks inside the core sample is to be tested, the following steps may be continued:

[0098] S13: Take out the core sample, take the core sample out of the sample barrel 1, and air-dry the core sample with air at room temperature to prevent the core sample from expanding and contracting due to high temperature, causing the volume change of the tiny gaps in the core sample, and affecting the accuracy of the test data.

[0099] S14: Apply load to the core sample. Place the core sample vertically on a plane according to the drilling state. Use a rubber hammer to hammer the upper surface area of ​​the core sample from the top with a fixed force to simulate the vehicle load. The number of hammering is 5-10 times. During the hammering process, avoid hammering on the side of the core sample to avoid damage to the core sample.

[0100] S15: Weigh the core sample again, weigh the core sample after hammering, and take the mass of the core sample as m0. Then collect the particle residues dropped during the hammering process and weigh them together with the core sample. The weighed weight is (m0); minimize the test error caused by breakage factors to subsequent tests.

[0101] S16: Reset the test conditions to keep the water level in the sample barrel 1 at height H and return the connecting pipe 3 to its original position.

[0102] S17: Put in the core sample, slowly put in the core sample, seal the sealing cover 2 and the port of the sample barrel 1, and adjust the liquid level height of the connecting tube 3 to h again through the syringe 5, and remove the syringe 5.

[0103] S18: Weigh three times, put the device without the syringe 5 on the balance 8 for overall weighing, with an accuracy of 0.002g, and record the mass at this time as M load .

[0104] S19: Synchronize the mass, insert the syringe 5, add clean water into the syringe 5, slowly control the opening and closing of the air valve, and slowly inject clean water into the sample barrel 1 until M load =M1, close the air valve, let it stand until the water surface is still, and read the water level height of the connecting pipe 3 as h1 load , then |h1 load -h1| means that we can preliminarily judge the effect of load on the volume of the material, because the core sample itself can slightly increase in volume due to the generation of fine cracks, so when the mass of M1 is reached, the water level h1 load Will be higher than h1.

[0105] According to theoretical analysis, when the core sample is subjected to load, fine cracks will appear inside, and the overall volume of the core sample will expand. When the water level is adjusted to h, the overall mass M load Will be smaller than M1.

[0106] S20: Secondary pressurization test: use the syringe 5 to push air into the sample barrel 1 until the liquid level in the connecting tube 3 reaches h2, and then close the air valve 6.

[0107] S21: Weigh four times, using the balance 8 to weigh the entire mass of the device excluding the syringe 5 as M2.

[0108] S22: Let it stand for 2-3 hours, and record the liquid level in the connecting pipe as h3 load .

[0109] S23: Weigh five times, using the balance 8 to weigh the mass of the entire device excluding the syringe 5 as M3, then |h2-h3 load | is the volume of fine cracks in the core sample that cannot be penetrated by water under normal pressure after the core sample is subjected to simulated load. The comparison between M2 and M3 is helpful to determine whether leakage occurs during the static process, and to prevent test errors caused by reduced quality of sealed gas inside the container due to leakage. If leakage occurs, the test needs to be repeated.

[0110] Figure 7 A flow chart showing the effect of freezing on the micro cracks inside the core sample of a method for testing the micro cracks of asphalt pavement materials according to an embodiment of the present invention is shown, with reference to Figure 7 As shown, in some embodiments, if the effect of freezing on the micro cracks inside the core sample is to be tested, the following steps may be continued after S9:

[0111] S13: Take out the core sample, take the core sample out of the sample barrel 1, and air-dry the core sample with air at room temperature to prevent the core sample from expanding and contracting due to high temperature, causing the volume change of the tiny gaps in the core sample, and affecting the accuracy of the test data.

[0112] S14: Freeze the core sample, isolate and seal the core sample, and put it in a refrigerator to prevent water vapor from penetrating into the core sample and affecting the accuracy of subsequent tests. The specific freezing temperature can be set between plus or minus ten degrees according to the lowest temperature in the area, and freeze it in a low temperature environment for 24 days, and then take out the core sample;

[0113] S15: Weigh the core sample again, weigh the frozen core sample, and take the mass of the core sample as m0. Then collect the particle residues dropped during the freezing process and weigh them together with the core sample, and the weighed weight is (m0); minimize the experimental errors caused by breakage factors to subsequent tests.

[0114] S16: Reset the test conditions to keep the water level in the sample barrel 1 at height H and return the connecting pipe 3 to its original position.

[0115] S17: Put in the core sample, slowly put in the core sample, seal the sealing cover and the port of the sample barrel, and adjust the liquid level height of the connecting tube 3 to h again through the syringe 5, and remove the syringe 5.

[0116] S18: Weigh three times, put the device without the syringe 5 on the balance 8 for overall weighing, with an accuracy of 0.002g, and record the mass at this time as M ice .

[0117] S19: Synchronize the quality and drain the water slowly to the outside through the drain valve 7 at the bottom of the sample barrel until M ice =M1, close the drain valve 7, let it stand until the water surface is still, and read the water level height of the connecting pipe 3 as h1 ice , then |h1 ice -h1| is the effect of freezing on the volume of the material.

[0118] According to theoretical analysis, after the core sample is frozen, thermal expansion and contraction will occur, and micro cracks will appear inside. The overall volume of the core sample will decrease. Adjust the water level to h. At this time, the overall mass M ice Will be greater than M1.

[0119] S20: Secondary pressurization test: use the syringe 5 to push air into the sample barrel 1 until the liquid level in the connecting tube 3 reaches h2, and then close the air valve 6.

[0120] S21: Weigh four times, using the balance 8 to weigh the entire mass of the device excluding the syringe 5 as M2.

[0121] S22: Let stand for 2-3 hours, and record the liquid level in connecting pipe 3 as h3 ice .

[0122] S23: Weigh five times, using the balance 8 to weigh the mass of the entire device excluding the syringe 5 as M3, then |h2-h3 ice | is the volume of fine cracks that cannot be penetrated by water under normal pressure in the core sample after partial freezing. The comparison of M2 and M3 can help to determine whether leakage occurs during the static process, and prevent test errors caused by reduced quality of sealed gas inside the container due to leakage. If leakage occurs, the test needs to be repeated.

[0123] Figure 8 A flow chart showing the effect of high temperature on micro cracks in a core sample according to a method for testing micro cracks in asphalt pavement materials according to an embodiment of the present invention is shown. Figure 7As shown, in some embodiments, if the self-healing effect of high temperature on micro cracks inside asphalt pavement materials is to be tested, the following steps may be continued after S9:

[0124] S13: Take out the core sample, take it out of the sample barrel, and air-dry it with air at room temperature to prevent the core sample from expanding and contracting due to high temperature, which may cause the volume change of the tiny gaps in the core sample and affect the accuracy of the test data.

[0125] S14: heating the core sample, placing the core sample in an oven for heating, the specific heating temperature can be set between plus or minus ten degrees according to the lowest temperature in the area, and keeping the temperature in a high temperature environment for 24 days, and taking out the core sample;

[0126] S15: Weigh the core sample again, weigh the core sample after hammering, and take the mass of the core sample as m0. Then collect the particle residues dropped during the hammering process and weigh them together with the core sample. The weighed weight is (m0); minimize the test error caused by breakage factors to subsequent tests.

[0127] S16: Reset the test conditions to keep the water level in the sample barrel 1 at height H and return the connecting pipe 3 to its original position.

[0128] S17: Put in the core sample, slowly put in the core sample, seal the sealing cover 2 and the port of the sample barrel 1, and adjust the liquid level height of the connecting tube 3 to h again through the syringe 5, and remove the syringe 5.

[0129] S18: Weigh three times, put the device without the syringe 5 on the balance 8 for overall weighing, with an accuracy of 0.002g, and record the mass at this time as M hot .

[0130] S19: Synchronize the mass, insert the syringe 5, add clean water into the syringe 5, slowly control the opening and closing of the air valve 6, and slowly inject clean water into the sample barrel 1 until M hot =M1, close the air valve 6, let it stand until the water surface is still, and read the water level height of the connecting pipe 3 as h1 ice , then |h1 ice -h1| is the effect of freezing on the volume of the material.

[0131] According to theoretical analysis, when the core sample is heated, it will expand and contract, and there will be micro cracks inside that will heal themselves. The overall volume of the core sample will increase. Adjust the water level to h. At this time, the overall mass M hot Will be smaller than M1.

[0132] S20: Secondary pressurization test: Use a syringe to push air into the sample barrel until the liquid level in the connecting tube reaches h2, and then close the air valve.

[0133] S21: Weigh four times, using the balance 8 to weigh the entire mass of the device excluding the syringe 5 as M2.

[0134] S22: Let it stand for 2-3 hours, and record the liquid level in the connecting pipe as h3 ice .

[0135] S23: Weigh five times, using the balance 8 to weigh the mass of the entire device excluding the syringe 5 as M3, then |h2-h3 ice | is the volume of fine cracks that cannot be penetrated by water under normal pressure in the core sample after partial freezing. The comparison of M2 and M3 can help to determine whether leakage occurs during the static process, and prevent test errors caused by reduced quality of sealed gas inside the container due to leakage. If leakage occurs, the test needs to be repeated.

[0136] In the description of this specification, the terms "connection", "installation", "fixation" and the like should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0137] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A testing device for testing micro cracks in asphalt pavement materials, characterized in that: include: A sample barrel (1) for containing liquid and drilled road surface core samples; A sealing cover (2), the sealing cover (2) being arranged on the top of the sample barrel (1); The connecting tube (3) is vertically inserted with the sealing cover (2), and its lower end is located below the liquid surface of the sample barrel (1). A plurality of scales are arranged on the peripheral side of the connecting tube (3) along its length direction, and the connecting tube (3) and the sealing cover (2) are sealed at the insertion point; A pressurizing device, the output port of which is plugged into the sealing cover (2) and communicates with the interior of the sample barrel (1), and the output port of the pressurizing device is sealed at the plugging point with the sealing cover (2); and further comprises Balance (8).

2. A testing device for testing micro-cracks of asphalt pavement materials according to claim 1, characterized in that: Also includes: An air valve (6) has one end sealedly connected to the sealing cover (2) and communicated with the interior of the sample barrel (1); the other end of the air valve (6) is used to be sealedly connected to the output port of the pressurizing device.

3. A testing device for testing micro cracks of asphalt pavement materials according to claim 2, characterized in that: The pressurizing device is a syringe (5), and the output port of the syringe (5) is sealed and plugged into the air inlet port of the air valve (6).

4. A testing device for testing micro cracks of asphalt pavement materials according to claim 1, characterized in that: A supporting seal (4) is provided between the connecting pipe (3) and the sealing cover (2), and the supporting seal (4) comprises A sealing pressure plate (41) is provided with a through hole matched with the connecting pipe (3), and the inner wall of the through hole is sealed and connected to the connecting pipe (3); A threaded tube (42) is fixedly connected to the bottom of the sealing pressure plate (41), the inner wall diameter of the threaded tube (42) is larger than the diameter of the through hole, and the through hole is located within the threaded tube (42); A support tube (43) is fixedly connected to the top of the sealing pressure plate (41) and is coaxial with the through hole. The inner wall diameter of the support tube (43) matches that of the connecting tube (3); The sealing cover (2) is provided with a thread groove (21) on the side of the connecting pipe (3) for threading with the threaded pipe (42).

5. A testing device for testing micro cracks of asphalt pavement materials according to claim 4, characterized in that: The diameter of the inner wall of the end portion of the support tube (43) connected to the sealing pressure plate (41) gradually increases to the inner wall of the other end of the support tube (43).

6. A testing device for testing micro-cracks of asphalt pavement materials according to claim 5, characterized in that: An abutment sealing ring (44) is arranged inside the port of the support tube (43).

7. A method for testing micro cracks in asphalt pavement materials, characterized in that: For use with the testing device according to any one of claims 1 to 6, the method comprising: Sampling: Drill core samples from the road surface to be tested; Dust removal: Use cleaning tools to remove dust from the core sample and remove floating dust on the surface of the core sample; Weigh the core, use a balance (8) to weigh the mass of the core sample as m, and slowly place the core sample into the sample bucket (1); Fill water: slowly inject clean water into the sample barrel (1) until the water level exceeds the core sample height, and record the water level as H; Closing the cover, placing a sealing cover (2) at the end of the sample barrel (1); Place the connecting tube (3) in place and insert it into the sealing cover (2), so that the lower end of the connecting tube (3) is located below the horizontal plane and the 0 scale on the side of the connecting tube is flush with the horizontal plane, connect the supporting seal (4) to keep the connecting tube (3) vertical; then insert the output port of the syringe (5) into the input port of the air valve (6); Adjust the initial height, and through the control of the air valve (6), reciprocate the pulling operation of the syringe (5) to realize the pressurization operation inside the sample barrel (1), accurately adjust the height change of the liquid level in the connecting tube (3), until the liquid level in the connecting tube (3) rises to the height h1, close the air valve (6), and remove the syringe (5); Second weighing: Place the device without the syringe (5) on a balance (8) and weigh the whole device with an accuracy of 0.002 g. Record the mass at this time as M1; For pressurized measurement, the syringe (5) is connected to the air inlet end of the air valve (6) again, the air valve (6) is opened, and the sample barrel (1) is pressurized again by the cooperation of the syringe (5) and the air valve (6) so that the liquid level inside the connecting pipe (3) rises by at least 100 cm, and the air valve (6) is closed. The liquid level height of the connecting pipe (3) at this time is recorded as h2: A primary error weighing, using a balance (8) to weigh the mass of the entire device excluding the syringe (5) as M2; Let it stand for 2-3 hours, record the liquid level in the connecting pipe (3), and record the liquid level as h3; Secondary error weighing, using a balance (8) to weigh the mass of the entire device excluding the syringe (5) as M3, the microscopic crack volume of the sample can be calculated using the inner wall diameter of the connecting tube (3), h3, and h2 data.

8. A method for testing micro cracks of asphalt pavement materials according to claim 7, characterized in that: After the pressure measurement, the following steps can be performed: Take out the core sample, take it out from the sample barrel (1), and air-dry it with air at room temperature; Apply load to the core sample, place the core sample on a plane according to the drilling state, and use a rubber hammer to hammer the core sample at a fixed frequency from the top of the core sample to simulate the vehicle load. The number of hammering times is 5-10 times; Weigh the core sample again, weigh the core sample after hammering, and take the mass of the core sample as m0. Then collect the particle residue dropped during the hammering process and weigh it together with the core sample. The weighed weight is (m0); Reset the test conditions so that the water level in the sample barrel (1) remains at height H and the connecting pipe (3) returns to its original position; Put in the core sample slowly, seal the sealing cover (2) and the port of the sample barrel (1), and adjust the liquid level of the connecting tube (3) to h again through the syringe (5), and remove the syringe (5); Weigh three times, place the device without the syringe (5) on a balance (8) and weigh the whole device with an accuracy of 0.002 g, and record the mass at this time as M load ; Synchronize the mass, insert the syringe (5), and slowly inject clean water into the sample barrel (1) until M load = M1, let it stand until the water surface is still, and read the water level of the connecting pipe (3) as h1 load , then |h1 load -h1| is the effect of the initial load on the material volume; Secondary pressure test: Use a syringe (5) to push air into the sample barrel (1) until the liquid level in the connecting tube (3) reaches h2, and then close the air valve (6); Weigh four times, using a balance (8) to weigh the mass of the entire device excluding the syringe (5) as M2; Let it stand for 2-3 hours and record the liquid level in the connecting pipe (3) as h3 load ; Weigh five times, using a balance (8) to weigh the mass of the entire device excluding the syringe (5) as M3, then |h2-h3 load | is the volume of micro cracks in the core sample that cannot be penetrated by water under normal pressure after the core sample is subjected to simulated load.

9. A method for testing micro cracks of asphalt pavement materials according to claim 7, characterized in that: After the pressure measurement, the following steps can be performed: Take out the core sample, take it out of the sample barrel, air-dry it with normal temperature air, isolate and seal the sample, put it in a refrigerator, set the specific temperature according to the lowest temperature in the area plus or minus ten degrees, and freeze it in a low temperature environment for 24 days, then take out the core sample; Weigh the core sample again, weigh the frozen core sample, and take the mass of the core sample as m0. Then collect the particle residues that fall during the freezing process and weigh them together with the core sample. The weighed weight is (m0); Reset the test conditions so that the water level in the sample barrel (1) remains at height H and the connecting pipe (3) returns to its original position; Put in the core sample slowly, seal the sealing cover (2) and the port of the sample barrel (1), and adjust the liquid level of the connecting tube (3) to h again through the syringe (5), and remove the syringe (5); Weigh three times, and place the device without the syringe (5) on a balance (8) for overall weighing with an accuracy of 0.002 g. Record the mass at this time as M ice ; Synchronize the mass and drain the sample through the drain valve (7) at the bottom of the sample bucket until M ice = M1, let it stand until the water surface is still, and read the water level of the connecting pipe (3) as h1 ice , then |h1 ice -h1| is the effect of freezing on the volume of the material; Secondary pressure test: Use a syringe (5) to push air into the sample barrel (1) until the liquid level in the connecting tube (3) reaches h2, and then close the air valve (6); Weigh four times, using a balance (8) to weigh the mass of the entire device excluding the syringe (5) as M2; Let it stand for 2-3 hours and record the liquid level in the connecting pipe as h3 ice ; Weigh five times, using a balance (8) to weigh the mass of the entire device excluding the syringe (5) as M3, then |h2-h3 ice | is the volume of micro cracks that cannot be penetrated by water under normal pressure in the core sample after partial freezing.

10. A method for testing micro cracks of asphalt pavement materials according to claim 7, characterized in that: After the pressure measurement, the following steps can be performed: Take out the core sample, take it out from the sample barrel (1), air dry it with air at room temperature, and then put it into an oven for heating. The specific temperature is set according to the highest temperature in the area plus or minus ten degrees. Keep it warm for 24 days and then take out the core sample; Weigh the core sample again, weigh the heated core sample, and take the mass of the core sample as m0. Then collect the particle residue that falls during the heating process and weigh it together with the core sample. The weighed weight is (m0); Reset the test conditions so that the water level in the sample barrel (1) remains at height H and the connecting pipe (3) returns to its original position; Put in the core sample slowly, seal the sealing cover (2) and the port of the sample barrel (1), and adjust the liquid level of the connecting tube (3) to h again through the syringe (5), and remove the syringe (5); Weigh three times, and place the device without the syringe (5) on a balance (8) for overall weighing with an accuracy of 0.002 g. Record the mass at this time as M hot ; Synchronize the mass, insert the syringe (5), and slowly inject clean water into the sample barrel (1) until M hot = M1, let it stand until the water surface is still, and read the water level of the connecting pipe (3) as h1 hot , then |h1 hot -h1| is the effect of high temperature on the volume of the material; Secondary pressure test: Use a syringe (5) to push air into the sample barrel (1) until the liquid level in the connecting tube (3) reaches h2, and then close the air valve; Weigh four times, using a balance (8) to weigh the mass of the entire device excluding the syringe (5) as M2; Let it stand for 2-3 hours and record the liquid level in the connecting pipe (3) as h3 hot ; Weigh five times, using a balance (8) to weigh the mass of the entire device excluding the syringe (5) as M3, then |h2-h3 hot | is the volume of micro cracks in the core sample that cannot be penetrated by water under high temperature and normal pressure.

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