A test method for evaluating steel bar corrosion using the surface expansion ratio method

Abstract

The present invention provides a test method for assessing the condition of steel bar corrosion using the surface expansion rate method, belonging to the field of geotechnical engineering testing technology. The method comprises the following steps: establishing a relationship formula between steel bar corrosion and concrete surface expansion based on the transmission mechanism of steel bar corrosion expansion to concrete; deriving and calculating the concrete surface expansion rate by testing the unevenness of the concrete surface; and quantitatively assessing the condition of steel bar corrosion. The test method for assessing the condition of steel bar corrosion using the surface expansion rate method provided by the present invention is an indirect method for assessing the condition of steel bar corrosion in concrete. Compared with traditional resistivity and half-cell potential methods, the method has the advantages of quantitative rating, fast and convenient operation, non-destructiveness to concrete, and no restrictions on the testing environment, making it easy to promote on a large scale.

Description

Technical Field

[0001] The invention belongs to the technical field of geotechnical engineering detection, and more specifically, relates to a test method for evaluating steel bar corrosion conditions using a surface expansion rate method. Background Art

[0002] In engineering design and construction, the main method for determining the corrosion condition of steel bars in concrete is the semi-nondestructive method, that is, the electrochemical method. The most commonly used methods are the half-cell potential method and the resistivity method. The half-cell potential method determines the degree of corrosion of steel bars by measuring the natural corrosion potential of the steel bars. It has the advantages of high sensitivity, continuous tracking and in-situ measurement. However, the measurement of corrosion potential only determines the probability of corrosion and cannot directly give the corrosion rate or corrosion speed. Summary of the Invention

[0003] The purpose of the present invention is to provide a test method for evaluating the corrosion status of steel bars using the surface expansion coefficient method, aiming to solve the technical problem that the method used to evaluate the degree or status of steel bar corrosion in concrete is not easy to directly obtain the degree or status of steel bar corrosion.

[0004] To achieve the above object, the present invention adopts a technical solution of providing a test method for evaluating the corrosion condition of steel bars using a surface expansion coefficient method, comprising the following steps:

[0005] Based on the transmission mechanism of steel bar corrosion and expansion to concrete, a formula for the relationship between steel bar corrosion and concrete surface expansion is established;

[0006] By testing the unevenness of the concrete surface, the concrete surface expansion rate is calculated and derived;

[0007] Quantitative assessment of steel bar corrosion condition.

[0008] In one possible implementation, according to the transmission mechanism of steel bar corrosion expansion to concrete, the steel bar diameter is set to r, the corrosion layer thickness is dr, and the steel bar volume expansion rate after single-sided corrosion is dV.

[0009]

[0010] Assuming the concrete cover thickness is h, the concrete surface expansion caused by steel bar corrosion is δ, then the surface expansion rate is dU, dU = δ / h. Due to the continuity of volume expansion, the expansion of corrosion expansion transferred to the concrete is dU' = δ / (h-πr / 8), then dU' ≥ dU. Considering dV = Du', then

[0011]

[0012] This formula establishes the relationship between steel corrosion and concrete surface expansion, and through quantitative grading, it can quantitatively assess the steel corrosion condition through the concrete surface expansion rate.

[0013] In one possible implementation, an instrument is designed to measure the unevenness of a concrete surface. The ultimate strain of the concrete is 0.0033, and the peak stress corresponds to a compressive strain of 0.002. The radial corrosion rate at which steel bar corrosion causes damage is:

[0014]

[0015] Due to the expansion of concrete volume and corrosion of steel bars, micro strain is generated, which causes the concrete strain to exceed the limit value and thus fail.

[0016] Similarly, when concrete damage occurs, the roughness of the concrete surface is δ = 0.002 × h. Therefore, the accuracy of the instrument for measuring the roughness of the concrete surface should meet the requirements, and its accuracy is 0.1 μm.

[0017] In one possible implementation, the steel bar corrosion condition is quantitatively graded and evaluated. Based on the measured concrete surface unevenness, the concrete surface expansion rate is calculated, and the steel bar corrosion degree is graded and evaluated according to the following conditions:

[0018] When the corrosion degree is level one, the concrete surface expansion rate is ≤0.0008, and the steel bar corrosion degree is slight corrosion;

[0019] When the corrosion degree is level 2, the concrete surface expansion rate is ≥0.0008 and ≤0.0016, and the steel bar corrosion degree is relatively serious;

[0020] When the corrosion degree is level three, the concrete surface expansion rate is ≥0.0016 and <0.002, the steel bar corrosion degree is severe, and fine cracks appear on the concrete surface;

[0021] When the corrosion level is level four, the concrete surface expansion rate is ≥0.002, the steel bar corrosion level is extremely severe, and the concrete is cracked.

[0022] 4. The repairing kit for automotive dents, according to claim 1, wherein a bottom of the foot stand comprises a through-hole, and the two foot stand comprises a through-hole, and the two foot stand comprises a through-hole, and the two foot stand comprises a through-hole, and the two foot stand comprises a through-hole, and the two foot stand comprises a through-hole.

[0023] In a possible implementation, the support block slides along the length direction of the main support slide rod, and scale lines are provided on the main support slide rod along its length direction, and the sliding position of the support block is positioned with reference to the scale lines.

[0024] In one possible implementation, the distance between the support blocks at both ends of the main support slide is adjusted by sliding at least one of the support blocks, and at the same time, the support feet slide on the concrete surface, and the concrete unevenness and expansion rate are determined by the data measured by the electronic measuring meter.

[0025] In one possible implementation, a controller electrically connected to the electronic measuring meter is provided on the main support slide, and the controller includes a data receiver, a data transmitter and a wireless communication unit. The data receiver is suitable for receiving and storing data measured by the electronic measuring meter, the data transmitter is suitable for sending data to a device or terminal outside the controller, and the wireless communication unit is suitable for realizing wireless communication with a device or terminal outside the controller.

[0026] In a possible implementation, at least one end of the main support sliding rod is detachably connected to a laser level, and the laser level is used to emit light in a horizontal direction to refer to the flatness of the concrete surface.

[0027] In a possible implementation, a mobile terminal is wirelessly connected to the wireless communication unit. The mobile terminal is suitable for receiving and displaying data collected by the electronic measuring meter. The mobile terminal has a memory suitable for storing data and a display suitable for displaying data.

[0028] The present invention provides a test method for assessing the corrosion condition of steel bars using a surface expansion rate method. The method comprises the following steps: establishing a relationship between steel bar corrosion and concrete surface expansion based on the transmission mechanism of steel bar corrosion expansion to concrete; calculating the concrete surface expansion rate by measuring the unevenness of the concrete surface; and quantitatively assessing the corrosion condition of the steel bars. The present invention provides an indirect method for assessing the corrosion condition of steel bars in concrete. Compared to conventional resistivity and half-cell potential methods, the method offers advantages such as quantifiable rating, quick and convenient operation, non-destructiveness to concrete, and freedom from testing environment restrictions, making it readily applicable for widespread adoption. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 A flowchart of a test method for evaluating steel bar corrosion using a surface expansion coefficient method provided by an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of an instrument structure for measuring concrete surface unevenness in a test method for evaluating steel bar corrosion conditions using a surface expansion rate method provided by an embodiment of the present invention;

[0032] Figure 3 A top view of an instrument for measuring concrete surface unevenness in a test method for evaluating steel bar corrosion using a surface expansion coefficient method provided by an embodiment of the present invention;

[0033] Figure 4 for Figure 2 The figure shows a schematic structural diagram of another embodiment of an instrument for measuring the unevenness of concrete surface in a test method for evaluating the corrosion condition of steel bars using the surface expansion rate method.

[0034] Description of reference numerals:

[0035] 1. Electronic measuring table; 2. Main support slide; 3. Support block; 4. Fixing bolt; 5. Measuring head; 6. Fixing piece; 7. Support foot; 8. Scale line; 9. Controller; 10. Laser level; 11. Mobile terminal. DETAILED DESCRIPTION

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] Please also refer to Figures 1 to 4 The present invention provides a test method for evaluating the corrosion condition of steel bars using the surface expansion method. The test method for evaluating the corrosion condition of steel bars using the surface expansion method comprises the following steps:

[0038] Based on the transmission mechanism of steel bar corrosion and expansion to concrete, a formula for the relationship between steel bar corrosion and concrete surface expansion is established;

[0039] By testing the unevenness of the concrete surface, the concrete surface expansion rate is calculated and derived;

[0040] Quantitatively evaluate the corrosion condition of steel bars, where the steel bars evaluated are those inside the concrete.

[0041] The present invention provides a test method for assessing the condition of steel bar corrosion using the surface expansion method. Compared to existing technologies, this method establishes a relationship between steel bar corrosion and concrete surface expansion based on the transmission mechanism of steel bar corrosion expansion to concrete. The concrete surface expansion rate is calculated by testing the unevenness of the concrete surface, and the steel bar corrosion condition is quantitatively assessed. The present invention's test method for assessing the condition of steel bar corrosion using the surface expansion method is an indirect method for assessing steel bar corrosion in concrete. Compared to traditional resistivity and half-cell potential methods, it offers advantages such as quantifiable rating, quick and convenient operation, non-destructiveness to concrete, and freedom from testing environment restrictions, making it easy to widely promote.

[0042] In some embodiments, see Figures 1 to 4 According to the transmission mechanism of steel bar corrosion expansion to concrete, the steel bar diameter is set to r and the corrosion layer thickness is dr. The volume expansion rate of the steel bar after single-sided corrosion is dV.

[0043]

[0044] Assuming the concrete cover thickness is h, the concrete surface expansion caused by steel bar corrosion is δ, then the surface expansion rate is dU, dU = δ / h. Due to the continuity of volume expansion, the expansion of corrosion expansion transferred to the concrete is dU' = δ / (h-πr / 8), then dU' ≥ dU. Considering dV = Du', then

[0045]

[0046] This formula establishes the relationship between steel corrosion and concrete surface expansion, and through quantitative grading, it can quantitatively assess the steel corrosion condition through the concrete surface expansion rate.

[0047] In some embodiments, see Figures 1 to 4 , design an instrument for measuring the unevenness of concrete surface. The ultimate strain of concrete is 0.0033, and the peak stress corresponds to a compressive strain of 0.002. The radial corrosion rate of steel bar corrosion causing damage is:

[0048]

[0049] Due to the expansion of concrete volume and corrosion of steel bars, micro strain is generated, which causes the concrete strain to exceed the limit value and thus fail.

[0050] Similarly, when concrete damage occurs, the roughness of the concrete surface is δ = 0.002 × h. Therefore, the accuracy of the instrument for measuring the roughness of the concrete surface should meet the requirements, and its accuracy is 0.1 μm.

[0051] In some embodiments, see Figures 1 to 4 , quantitatively grade and evaluate the steel bar corrosion condition, calculate the concrete surface expansion rate based on the measured concrete surface unevenness, and grade and evaluate the steel bar corrosion degree according to the following conditions:

[0052] When the corrosion degree is level one, the concrete surface expansion rate is ≤0.0008, and the steel bar corrosion degree is slight corrosion;

[0053] When the corrosion degree is level 2, the concrete surface expansion rate is ≥0.0008 and ≤0.0016, and the steel bar corrosion degree is relatively serious;

[0054] When the corrosion degree is level three, the concrete surface expansion rate is ≥0.0016 and <0.002, the steel bar corrosion degree is severe, and fine cracks appear on the concrete surface;

[0055] When the corrosion level is level four, the concrete surface expansion rate is ≥0.002, the steel bar corrosion level is extremely severe, and the concrete is cracked.

[0056] The above-mentioned contents are as follows:

[0057]

[0058] The present method utilizes the surface expansion method to assess the corrosion of steel bars in concrete. By studying the transmission mechanism of steel bar corrosion and expansion into concrete, the relationship between steel bar corrosion and concrete surface expansion is established. This correspondence is then quantified and graded, achieving the goal of assessing steel bar corrosion properties through the concrete expansion rate. This method, an indirect method for assessing steel bar corrosion in concrete, offers advantages over traditional resistivity and half-cell potential methods, including quantifiable ratings, rapid and convenient operation, non-destructiveness to components, and freedom from testing environment restrictions, making it readily applicable for widespread adoption.

[0059] In some embodiments, see Figures 1 to 4 , an instrument for measuring the unevenness of a concrete surface, comprising an electronic measuring meter 1, a main support slide 2, two support blocks 3, two fixing bolts 4, a measuring head 5, a fixing part 6 and two supporting feet 7, wherein the main support slide 2 is arranged horizontally and has a mounting hole in the middle of the length direction, the electronic measuring meter 1 passes through the mounting hole and is arranged vertically, with the upper end located above the main support slide 2 and the lower end located below the main support slide 2, the lower end being the measuring end and the measuring head 5, the two ends of the main support slide 2 are respectively slidably connected to the support blocks 3, and the support blocks 3 are penetrated with a There is a fixing bolt 4, which is screwed to abut against the main support slide 2 to limit the position of the support block 3. The lower end of the support block 3 is provided with a support foot 7, which is used to abut against the concrete surface to be measured. The flatness of the concrete surface is measured by the electronic measuring meter 1. The mounting hole is filled with the fixing member 6 suitable for fixing the electronic measuring meter 1. The electronic measuring meter 1 is used to measure the distance between the measuring head 5 and the concrete surface to be measured. By calculating the difference between multiple measurement values, the unevenness and expansion rate of the concrete surface are obtained. By adjusting the distance between the support blocks 3 at both ends, when the data of the mat measuring meter changes, it can be indicated that the concrete surface here is uneven, indicating that there is a phenomenon of concrete expansion. By continuously measuring with the electronic measuring meter 1 and then calculating the difference, the unevenness data can be obtained, and then the concrete surface expansion rate can be derived by calculation through the formula.

[0060] This instrument is used to measure the degree of concrete expansion caused by steel bar corrosion. The instrument can realize continuous measurement of the flatness of the concrete surface from the non-reinforced area to the steel bar corrosion expansion area, and the difference is calculated to obtain the concrete surface expansion rate.

[0061] The fixing member 6 can be a sleeve or the like for fixing the electronic meter 1. The sleeve is inserted into the mounting hole, and the middle portion of the electronic meter 1 is inserted into the sleeve, which can limit and fix the electronic meter 1. The sleeve and the mounting hole are fixedly connected by friction, and the sleeve is fixedly connected to the electronic meter 1. The fixing member 6 can also be a filler that fills the gap between the mounting hole and the electronic meter 1. The filler can be hardened (such as plasticine). Once hardened, it is used to fix the electronic meter 1, making installation convenient.

[0062] In order to refer to the moving position of the support block 3, or to refer to the movement of the support block 3 to achieve equal distance, in some embodiments, refer to Figures 1 to 4 The support block 3 slides along the length of the main support slide 2. The main support slide 2 is provided with scale lines 8 along its length. The sliding position of the support block 3 is determined by reference to the scale lines 8. The scale lines 8 can be used to reference the movement position of the support block 3. For example, the support block 3 can move one centimeter at a time. By moving the support block 3 multiple times and observing the changes in the data on the electronic measuring meter 1, the flatness of the concrete surface can be determined. The data measured by the electronic measuring meter 1 can also be recorded. By calculating the difference between multiple data values ​​(such as the maximum value minus the minimum value), the flatness and expansion rate of the concrete surface can be determined and calculated.

[0063] In some embodiments, see Figures 1 to 4 The distance between the support blocks 3 at each end of the main support slide 2 is adjusted by sliding at least one of the support blocks 3. Simultaneously, the support feet 7 slide across the concrete surface, and the electronic measuring meter 1 measures the concrete's unevenness and expansion rate. A chute is provided along the length of the main support slide 2, and the support blocks 3 slide within this chute. The position of the support blocks 3 can be adjusted by pushing them. After adjustment, they can be re-secured by tightening the fixing bolts 4, providing convenient operation and flexible movement.

[0064] In some embodiments, see Figures 1 to 4 The main support slide 2 is provided with a controller 9 electrically connected to the electronic measuring meter 1. The controller 9 includes a data receiver, a data transmitter, and a wireless communication unit. The data receiver is suitable for receiving and storing data measured by the electronic measuring meter 1, the data transmitter is suitable for transmitting data to a device or terminal outside the controller 9, and the wireless communication unit is suitable for wireless communication with a device or terminal outside the controller 9. By providing this controller 9 (which is a prior art product with functions such as recording, storage, and signal transmission and reception), the data measured by the electronic measuring meter 1 can be recorded and stored, and communicated with external mobile devices. After connecting to the external mobile device, the concrete flatness information at the current time can be remotely viewed through the mobile device.

[0065] In some embodiments, see Figures 1 to 4 At least one end of the main support slide 2 is detachably connected to a laser level 10, and the laser level 10 is used to emit light in the horizontal direction to refer to the flatness of the concrete surface. By setting up the laser level 10, it is possible to emit rays in the horizontal direction. The rays are a reference for the flatness of the concrete. If it is found that the rays formed on the concrete surface are not parallel to the rays, or the distance between the two changes, it means that the concrete surface is uneven. At this time, a ruler or other tool can be used to measure again, and the difference in the unevenness can be calculated, and then the concrete surface expansion rate can be calculated. The concrete surface expansion rate is calculated by this method to evaluate the corrosion condition of the steel bars inside the concrete. The process is relatively simple, fast and convenient. The above-mentioned or following components refer to concrete (surface).

[0066] Specifically, there are various ways of the above-mentioned detachable connection, such as the detachable connection achieved by bolt fastening in the prior art, or the detachable connection achieved by using a strap or a clamp.

[0067] In some embodiments, see Figures 1 to 4 A mobile terminal 11 is wirelessly connected to the wireless communication unit. The mobile terminal 11 is adapted to receive and display data collected by the electronic measuring meter 1 and includes a memory for storing data and a display for displaying data. Mobile terminal 11 is similar to a conventional remote control or control panel. By wirelessly connecting to controller 9 and the like, the concrete surface flatness information can be viewed on mobile terminal 11, making it convenient for remote workers to observe.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A test method for evaluating the corrosion condition of steel bars using the surface expansion coefficient method, characterized in that: The following steps are involved: Based on the transmission mechanism of steel bar corrosion and expansion to concrete, a formula for the relationship between steel bar corrosion and concrete surface expansion is established; By testing the unevenness of the concrete surface, the concrete surface expansion rate is calculated and derived; Quantitatively assess the corrosion status of steel bars; According to the transmission mechanism of steel bar corrosion expansion to concrete, assuming the steel bar diameter is r and the corrosion layer thickness is dr, the steel bar volume expansion rate after single-sided corrosion is dV, then Assuming the concrete cover thickness is h, the concrete surface expansion caused by steel bar corrosion is δ, then the surface expansion rate is dU, dU=δ / h. Due to the continuity of volume expansion, the expansion of corrosion expansion transferred to the concrete is dU'=δ / (h-πr / 8), then dU'≥dU. Considering dV=Du', then This formula establishes the relationship between steel corrosion and concrete surface expansion, and through quantitative grading, it can quantitatively assess the steel corrosion condition through the concrete surface expansion rate.

2. The test method for evaluating steel bar corrosion using the surface expansion coefficient method according to claim 1, wherein: Design an instrument for measuring the unevenness of concrete surfaces. The ultimate strain of concrete is 0.0033, and the peak stress corresponds to a compressive strain of 0.

002. The radial corrosion rate at which steel bar corrosion causes damage is: Due to the expansion of concrete volume and corrosion of steel bars, micro strain is generated, which causes the concrete strain to exceed the limit value and thus fail. Similarly, when concrete damage occurs, the roughness of the concrete surface is δ=0.002×h, so the accuracy of the instrument for measuring the roughness of the concrete surface should meet the requirements, and its accuracy is 0.1μm.

3. The test method for evaluating steel bar corrosion using the surface expansion coefficient method according to claim 1, characterized in that: The steel bar corrosion condition is quantitatively graded and evaluated. Based on the measured concrete surface unevenness, the concrete surface expansion rate is calculated, and the steel bar corrosion degree is graded and evaluated according to the following conditions: When the corrosion degree is level one, the concrete surface expansion rate is less than 0.0008, and the steel bar corrosion degree is slight corrosion; When the corrosion degree is level 2, the concrete surface expansion rate is ≥0.0008 and <0.0016, and the steel bar corrosion degree is relatively serious; When the corrosion degree is level three, the concrete surface expansion rate is ≥0.0016 and <0.002, the steel bar corrosion degree is severe, and fine cracks appear on the concrete surface; When the corrosion level is level four, the concrete surface expansion rate is ≥0.002, the steel bar corrosion level is extremely severe, and the concrete is cracked.

4. The test method for evaluating steel bar corrosion using the surface expansion coefficient method according to claim 1, wherein: The tool is connected with the fixing member to form a circle, and the fixing member is connected with the fixing member to form a circle.

5. A test method for evaluating steel bar corrosion using a surface expansion coefficient method as claimed in claim 4, characterized in that: The support block slides along the length direction of the main support slide rod. The main support slide rod is provided with scale lines along its length direction. The sliding position of the support block is positioned with reference to the scale lines.

6. A test method for evaluating steel bar corrosion using a surface expansion coefficient method as claimed in claim 4, characterized in that: The distance between the support blocks at both ends of the main support slide is adjusted by sliding at least one of the support blocks, and at the same time the support feet slide on the concrete surface, and the concrete unevenness and expansion rate are determined by the data measured by the electronic measuring meter.

7. A test method for evaluating steel bar corrosion using a surface expansion coefficient method as claimed in claim 4, characterized in that: A controller electrically connected to the electronic measuring meter is provided on the main support slide, and the controller includes a data receiver, a data transmitter and a wireless communication unit. The data receiver is suitable for receiving and storing data measured by the electronic measuring meter, the data transmitter is suitable for sending data to a device or terminal outside the controller, and the wireless communication unit is suitable for realizing wireless communication with a device or terminal outside the controller.

8. A test method for evaluating steel bar corrosion using a surface expansion coefficient method as claimed in claim 4, characterized in that: At least one end of the main support sliding rod is detachably connected to a laser level, and the laser level is used to emit light in a horizontal direction to refer to the flatness of the concrete surface.

9. A test method for evaluating steel bar corrosion using a surface expansion coefficient method as claimed in claim 7, characterized in that: A mobile terminal is wirelessly connected to the wireless communication unit. The mobile terminal is suitable for receiving and displaying data collected by the electronic measuring meter. The mobile terminal has a memory suitable for storing data and a display suitable for displaying data.

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