Method for rapidly measuring cracks of concrete structure

Abstract

The invention discloses a method for rapidly measuring cracks of a concrete structure. The method comprises the following steps: S1, selecting a test part; s2, cleaning the surface of the concrete; s3, arranging ultrasonic measuring points; s4, connecting the probe with the equipment; s5, performing cross-seam ultrasonic testing and non-cross-seam ultrasonic testing respectively; s6, recording the test distance when the head wave is inverted; s7, the actual sound wave propagation distance and the concrete sound velocity of each non-cross-joint measuring point are solved; and S8, calculation is conducted according to a crack depth formula, in the step S1, the positions of steel bars in the concrete structure are avoided when test parts are selected, and the test parts are the two walls of the concrete structure. According to the rapid measuring method for the concrete structure crack, when the surface of the concrete is polished through the grinding wheel, dust and particulate matter can be prevented from entering the concrete crack in the polishing process, so that the crack does not need to be cleaned after polishing, and the working efficiency is improved. Therefore, the crack of the concrete structure can be measured quickly.

Description

Technical Field

[0001] The invention relates to the technical field of concrete structure crack measurement, and in particular to a method for rapid concrete structure crack measurement. Background Art

[0002] In the field of civil engineering, concrete has the advantages of low price, high compressive strength, high plasticity, and low maintenance cost. It is currently the most widely used building material. Concrete structures can be divided into reinforced concrete structures and prestressed structures. Reinforced concrete structures usually work with cracks. In management and maintenance, we only care about whether the crack size exceeds the limit. Prestressed concrete structures do not allow tensile stress to exceed the allowable value, that is, cracks are not allowed. When cracks appear in prestressed concrete components or cracks in reinforced concrete components exceed the limit, it will cause secondary diseases such as carbonization of concrete components, peeling of protective layers, and corrosion of steel bars, thereby reducing its bearing capacity and durability. Therefore, it is necessary to detect cracks in concrete. Microcracks in concrete generally refer to cracks with a width of less than 0.2mm. They are the most fundamental form of cracks and are usually caused by construction, operation loads and environmental factors. The increase in external loads or further deterioration of the environment will cause microcracks to continue to develop and open, thereby affecting the use function of the structure. Timely detection of microcracks on the surface of concrete components is of great significance to the operation and maintenance of components, especially for projects with high requirements for waterproof performance.

[0003] At present, in addition to the traditional means of naked eye observation, concrete crack detection also includes advanced non-destructive testing technologies such as digital photography recognition, ultrasound, infrared, radar and CT. It is mainly suitable for cracks that are obviously opened and not less than 0.2mm in width, and the surface is required to be clean and free of dirt. In order to keep the surface clean and free of dirt, the concrete surface will be polished or smoothed with high-strength quick-setting mortar. When grinding with a grinding wheel, some dust and particles will enter the cracks during the grinding process, which will affect the measurement. In order to avoid the cracks caused by the entry of dust and particles affecting the measurement results, the dust and particles that have entered the cracks need to be cleaned. Since a certain amount of cleaning time is required during the cleaning process, the measurement rate is affected. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for quickly measuring cracks in a concrete structure, which can effectively solve the technical problems in the background technology.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for quickly measuring cracks in a concrete structure comprises the following steps:

[0007] S1. Select the test site;

[0008] S2. Clean the concrete surface;

[0009] S3. Arrange ultrasonic measuring points;

[0010] S4, connecting the probe to the equipment;

[0011] S5. Perform ultrasonic tests with and without seam crossings respectively;

[0012] S6. Record the test distance when the first wave is inverted;

[0013] S7. Calculate the actual propagation distance of the sound wave and the concrete sound velocity at each measuring point that does not cross the joint;

[0014] S8. Calculate according to the crack depth formula.

[0015] Preferably, in S1, when selecting the test part, the steel bar position in the concrete structure is avoided, and the test part is the two walls of the concrete structure.

[0016] Preferably, in S2, the purpose of cleaning the concrete surface is to make the concrete surface in the peripheral range of the direction of the connection between the two probes flat, so as to facilitate measurement. The cleaning method can be grinding or smoothing with high-strength quick-setting mortar. A grinding wheel can be used for grinding. When using a grinding wheel, a ring that matches the grinding wheel is placed at the grinding position, the inner diameter of the ring is larger than the diameter of the grinding wheel, and then the grinding wheel is embedded in the ring, and the grinding wheel is in contact with the concrete. When the grinding wheel is grinding, the ring moves synchronously with the grinding wheel. The ring prevents dust and debris generated during the grinding process of the grinding wheel from falling into the cracks, and also prevents debris generated during the rotation of the grinding wheel from splashing to both sides. When smoothing with mortar, the smoothing mortar must be well combined with the concrete.

[0017] Preferably, in S3, one or more measuring points are arranged for each crack, and the transceiver probes should be arranged across the crack on both sides of the crack. When arranging the transceiver probes, the probe connection line should be avoided from being parallel to the nearby steel bars within a distance range.

[0018] Preferably, in S5, a coupling agent is used during the test to ensure that the probe ground and the concrete surface are well coupled, the transceiver probe keeps moving slowly when moving, and the transceiver probe moves synchronously, and no mud, sand or air is mixed in the coupling layer.

[0019] Preferably, in S5, when the cross-crack test is performed, the transmitting and receiving transducers are placed on the same side near the crack, and when the cross-crack test is not performed, the transmitting and receiving transducers are placed respectively at two symmetrical points with the direction of the measured crack as the plane symmetry axis.

[0020] Preferably, in S7, a "time-distance" coordinate diagram is drawn according to the non-slit-crossing measurement results, or a linear regression analysis method is used to find the regression line equation between the sound time and the distance measurement.

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

[0022] In the present invention, when the concrete surface is ground by a grinding wheel, dust and particles during the grinding process can be prevented from entering the concrete cracks, so that there is no need to clean the cracks after grinding, so that the measurement of the cracks in the concrete structure can be completed quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a flowchart of a method for quickly measuring cracks in a concrete structure. DETAILED DESCRIPTION

[0024] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0025] like Figure 1 A method for rapid measurement of cracks in a concrete structure is shown, comprising the following steps: S1, selecting a test site; S2, cleaning the concrete surface; S3, arranging ultrasonic measuring points; S4, connecting the probe to the equipment; S5, performing ultrasonic tests across the crack and without the crack respectively; S6, recording the test distance when the first wave is inverted; S7, calculating the actual propagation distance of the sound wave at each measuring point without the crack and the concrete sound velocity; S8, calculating according to the crack depth formula.

[0026] In S1, the steel bar position in the concrete structure is avoided when selecting the test site, and the test site is the two walls of the concrete structure; in S2, the concrete surface is cleaned to make the concrete surface in the surrounding range of the connection direction of the two probes flat, so as to facilitate measurement. The cleaning method can be grinding or smoothing with high-strength quick-setting mortar. Grinding can be done with a grinding wheel. When using a grinding wheel, a ring that matches the grinding wheel is placed at the grinding position, and the inner diameter of the ring is larger than the diameter of the grinding wheel. Then the grinding wheel is embedded in the ring and the grinding wheel is in contact with the concrete. When the grinding wheel is grinding, the ring moves synchronously with the grinding wheel. The ring prevents the dust and debris generated during the grinding process of the grinding wheel from falling into the cracks, and also prevents the debris generated during the rotation of the grinding wheel from splashing to both sides. When smoothing with mortar, the smoothing mortar must be in contact with the concrete The soil is well bonded; in S3, one or more measuring points are arranged for each crack, and the transceiver probes should be arranged on both sides of the crack across the crack. When arranging the transceiver probes, the probe connection line should be avoided to be parallel to the nearby steel bars within the distance range; in S5, a coupling agent is used during the test to ensure that the probe ground and the concrete surface are well coupled, the transceiver probes keep moving slowly when moving, and the transceiver probes move synchronously, and no mud or air should be mixed in the coupling layer; in S5, the transmitting and receiving transducers are placed on the same side near the crack during the cross-crack test, and the transmitting and receiving transducers are placed at two symmetrical points with the direction of the measured crack as the plane symmetry axis during the non-cross-crack test; in S7, a "time-distance" coordinate diagram is drawn according to the non-cross-crack measurement results, or a linear regression analysis method is used to obtain the regression line equation between the sound time and the distance measurement.

[0027] It should be noted that the present invention is a method for rapid measurement of cracks in concrete structures. When in use, a test site is selected, and the steel bar position in the concrete structure is avoided when selecting the test site. The test site is the two walls of the concrete structure. When cleaning the concrete surface, the purpose of cleaning the concrete surface is to make the concrete surface in the peripheral range of the connection direction of the two probes flat, so as to facilitate measurement. The cleaning method can be grinding, or it can be smoothed with high-strength fast-setting mortar. A grinding wheel can be used for grinding. When using a grinding wheel, a circular ring matched with the grinding wheel is placed at the grinding position, and the inner diameter of the circular ring is larger than the diameter of the grinding wheel. Then the grinding wheel is embedded in the circular ring, and the grinding wheel is made to contact with the concrete. When the grinding wheel is grinding, the circular ring moves synchronously with the grinding wheel. The circular ring prevents dust and debris generated during the grinding process of the grinding wheel from falling into the cracks, and also prevents debris generated during the grinding process of the grinding wheel from rotating. Chips splash to both sides. When using mortar for leveling, the leveling mortar must be well combined with the concrete. When arranging ultrasonic measuring points, one or more measuring points are arranged for each crack. The transceiver probes should be arranged across the crack on both sides of the crack. When arranging the transceiver probes, avoid the probe connection line being parallel to the nearby steel bars within the distance range. When conducting cross-crack and non-cross-crack ultrasonic tests, the transmitting and receiving transducers are placed on the same side near the crack during cross-crack testing. During non-cross-crack testing, the transmitting and receiving transducers are placed at two symmetrical points with the direction of the measured crack as the plane symmetry axis. After recording the test distance when the first wave is inverted, the actual propagation distance of the sound wave and the concrete sound velocity of each measuring point without crossing the crack are calculated. Finally, the crack depth formula is used for calculation. When conducting non-cross-crack testing, a "time-distance" coordinate diagram is drawn according to the non-cross-crack measurement results, or the regression line equation between the sound time and the distance measurement is calculated using the linear regression analysis method.

[0028] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for rapid measurement of cracks in concrete structures, characterized in that: The following steps are involved: S1. Select the test site; S2. Clean the concrete surface; S3. Arrange ultrasonic measuring points; S4, connecting the probe to the equipment; S5. Perform ultrasonic tests with and without seam crossings respectively; S6. Record the test distance when the first wave is inverted; S7. Calculate the actual propagation distance of the sound wave and the concrete sound velocity at each measuring point that does not cross the joint; S8. Calculate according to the crack depth formula.

2. A method for rapid measurement of cracks in concrete structure according to claim 1, characterized in that: In S1, when selecting the test site, avoid the steel bar position in the concrete structure, and the test site is the two walls of the concrete structure.

3. A method for rapid measurement of cracks in concrete structure according to claim 2, characterized in that: In S2, the purpose of cleaning the concrete surface is to make the concrete surface in the surrounding range of the connection direction of the two probes flat, so as to facilitate measurement. The cleaning method can be grinding or smoothing with high-strength quick-setting mortar. A grinding wheel can be used for grinding. When using a grinding wheel, a ring that matches the grinding wheel is placed at the grinding position, and the inner diameter of the ring is larger than the diameter of the grinding wheel. Then the grinding wheel is embedded in the ring and the grinding wheel is in contact with the concrete. When the grinding wheel is grinding, the ring moves synchronously with the grinding wheel. The ring prevents dust and debris generated during the grinding process of the grinding wheel from falling into the cracks, and also prevents debris generated during the rotation of the grinding wheel from splashing to both sides. When smoothing with mortar, the smoothing mortar must be well combined with the concrete.

4. A method for rapid measurement of cracks in concrete structure according to claim 3, characterized in that: In S3, one or more measuring points are arranged for each crack, and the transceiver probes should be arranged across the crack on both sides of the crack. When arranging the transceiver probes, it should be avoided that the probe connection line is parallel to the nearby steel bars within a distance range.

5. A method for rapid measurement of cracks in concrete structure according to claim 4, characterized in that: In the S5, a coupling agent is used during the test to ensure that the probe ground and the concrete surface are well coupled, the transceiver probes are kept moving slowly when moving, and the transceiver probes move synchronously, and no mud, sand or air is mixed in the coupling layer.

6. A method for rapid measurement of cracks in concrete structure according to claim 5, characterized in that: In S5, when testing across cracks, the transmitting and receiving transducers are placed on the same side near the cracks; when testing without testing across cracks, the transmitting and receiving transducers are placed at two symmetrical points with the direction of the crack being the plane symmetry axis.

7. A method for rapid measurement of cracks in concrete structure according to claim 6, characterized in that: In S7, a "time-distance" coordinate diagram is drawn according to the non-slit-crossing measurement result, or a linear regression analysis method is used to find the regression line equation between the sound time and the distance measurement.

Images