JP2011257245A - Corrosion amount estimation method, corrosion amount estimation device, and management method for reinforced concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To estimate corrosion of an existent reinforced concrete structure, using reinforcing bars in irregular shapes, more precisely than before.SOLUTION: A corrosion amount estimation method of estimating the amount of corrosion of reinforced concrete using reinforcing bars in irregular shapes includes a constant information acquisition step of acquiring constant information on constants by irregular-shape reinforcing bar diameters found from correlation between amounts of corrosion of a test piece made of reinforced concrete and measurement indexes of cracking of the test piece; and a corrosion amount estimation step of estimating the amount of corrosion of the reinforced concrete to be estimated based on in-cracking corrosion amount information on an amount of corrosion during cracking obtained from the test piece, cracking-width information on a cracking width of the reinforced concrete whose amount of corrosion is to be estimated, cover thickness information on a cover thickness of the reinforced concrete to be estimated, and the constant information specified with reinforcing bar diameter information on irregular bar diameters of the reinforced concrete to be estimated.

Description

  The present invention relates to a corrosion amount estimation method, a corrosion amount estimation device, and a reinforced concrete management method.

  Many techniques for evaluating the corrosion state of reinforced concrete and cracks generated in reinforced concrete are known. For example, Patent Document 1 discloses a method of calculating a rusting time of a reinforcing bar in a reinforced concrete by obtaining a difference in a concrete neutralization depth as a parameter α from a test, and a corrosion rate due to relative humidity at a reinforcing bar position in the reinforced concrete. Is calculated from the test, and a method of calculating the corrosion weight loss ratio after the start of corrosion is disclosed.

  Patent Document 2 also calculates the estimated average crack width from the estimated unit crack width calculated based on the actual measurement data of cracks generated in the reinforced concrete structure and the estimated number of unit cracks, and calculates the estimated average crack width and In addition, a technique for estimating the maximum crack width of a newly reinforced concrete structure based on the relationship between the actual average crack width and the actual maximum crack width acquired based on the actual crack data is disclosed.

  Patent Document 3 discloses, as an independent management support system for concrete structures, the crack width data of a concrete structure periodically measured by an administrator using a portable crack width measuring device to an independent management support server. In the self-management support server, the received crack width data is stored in time series, and the deterioration degree of the concrete structure is determined based on the temporal change of the crack width data measured periodically. Is disclosed.

  Non-Patent Document 1 describes a technique for predicting the life of reinforced concrete structures due to corrosion, such as the cover thickness, the diameter of steel bars, salinity, water cement ratio, temperature, humidity, and oxygen concentration. It is disclosed to predict the lifetime of

  In addition, the conventional life prediction of reinforced concrete structures is based on the assumption that round bars are used as reinforcing bars, but it is known that deformed reinforcing bars have a greater cracking limit corrosion amount than round bars (for example, (See Patent Document 2). Furthermore, the life prediction of conventional reinforced concrete structures is mostly for salt-mixed concrete, but it is known that rust forms differ between corrosion due to salt damage and corrosion due to neutralization of concrete ( For example, refer nonpatent literature 3.).

Japanese Patent No. 4108568 JP 2009-19472 A JP 2008-107198 A JP 2002-328096 A

Shigeru Morinaga, Kazuo Irino, Tatsumi Ota, Atsushi Tsuchimoto, “Life Prediction of Reinforced Concrete Structures Due to Corrosion, Proceedings of Concrete Engineering”, January 1990, Vol. 1, No. 1, p. 177-188 Koji Takewaka, Susumu Matsumoto, "Effects of Rebar Corrosion in Concrete on Mechanical Properties of RC Members" Proceedings of the 6th Annual Conference on Concrete Engineering, 1984, p. 177-180 Kumiko Suda, MISRA Sudhir, Kenichi Motohashi, “Analytical Study on the Limiting Corrosion of Corrosion Cracks” Annual Report of Concrete Engineering, 1992, Vol. 14, no. 1, p. 751-756

  Many techniques for evaluating the corrosion state of reinforcing steel in reinforced concrete and cracks generated in reinforced concrete (hereinafter referred to as conventional evaluation techniques) are known. And most of the conventional evaluation techniques use round steel as a reinforcing bar for reinforced concrete and assume corrosion due to salt damage. However, in existing reinforced concrete structures, deformed reinforcing bars are often used instead of round steel bars, and there is a concern that conventional evaluation techniques cannot accurately evaluate existing reinforced concrete structures.

  In view of the above problems, an object of the present invention is to provide a technique capable of estimating corrosion in an existing reinforced concrete structure using deformed reinforcing bars more accurately than in the past.

  In the present invention, in order to solve the above-described problems, the amount of corrosion is determined based on the constant for each deformed rebar diameter obtained from the specimen and the corrosion at the time of crack occurrence, and the crack width and cover thickness of the reinforced concrete to estimate the amount of corrosion. It was decided to estimate.

  More specifically, the present invention relates to a corrosion amount estimation method for estimating a corrosion amount of reinforced concrete using deformed reinforcing bars, and a correlation between a corrosion amount of a specimen made of reinforced concrete and a measurement index of cracks of the specimen. Constant information acquisition step for acquiring constant information on constants for each deformed reinforcing bar diameter obtained from the above, information on the amount of corrosion at the time of cracking obtained from the specimen, and the reinforced concrete subject to estimation of the amount of corrosion Based on the crack width information related to the crack width of the reinforced concrete, the cover thickness information related to the cover thickness of the reinforced concrete to be estimated, and the constant information corresponding to the deformed reinforcing bar diameter of the reinforced concrete to be estimated A corrosion amount estimation step for estimating a corrosion amount of the target reinforced concrete.

  According to the corrosion amount estimation method according to the present invention, when estimating the corrosion amount, the amount of corrosion in an existing reinforced concrete structure using deformed reinforcing bars is accurately estimated by considering constant information regarding the constants for each deformed reinforcing bar diameter. Can be estimated. The constant information can be obtained by obtaining in advance a measurement index of the amount of corrosion of the specimen and the crack of the specimen. An example of the measurement index is the crack width of the specimen. Note that the amount of surface displacement may be used instead of the crack width. The amount of surface displacement means the amount of deformation of cracks existing on the surface of the specimen. The information on the amount of corrosion at the time of occurrence of cracks is information on the amount of corrosion at the time of occurrence of cracks obtained from the specimen. In the corrosion amount estimation method according to the present invention, constant information and crack occurrence corrosion information can be obtained in advance from a specimen. Therefore, the amount of corrosion can be estimated from the crack width information, the cover thickness information, and the constant information corresponding to the deformed reinforcing bar diameter of the reinforced concrete to be estimated.

  Here, among reinforced concrete structures, in a building structure, corrosion due to neutralization of reinforced concrete is more problematic than corrosion due to salt damage. However, many conventional evaluation techniques relate to corrosion due to salt damage, and a technique capable of estimating the amount of corrosion due to neutralization of reinforced concrete is required.

Therefore, in the corrosion amount estimation method according to the present invention, the cracking corrosion amount information includes neutralization corrosion amount information due to neutralization of reinforced concrete and salt damage corrosion amount information due to salt damage, and the constant information is Neutralization constant information due to neutralization of reinforced concrete, and salt damage constant information due to salt damage, and in the corrosion amount estimation step, when the corrosion of deformed reinforcing bars in the reinforced concrete to be estimated is due to the neutralization of the reinforced concrete, Using the neutralization corrosion amount information as the crack occurrence corrosion amount information, and using the neutralization constant information as the constant information, estimating the corrosion amount of the reinforced concrete to be estimated, and the estimation target If the corrosion of deformed bars in reinforced concrete is due to salt damage, the amount of salt damage corrosion information is used as the amount of corrosion information at the time of crack occurrence. The use, as the constant information, using the salt damage constant information may be estimated amount of corrosion of reinforced concrete to be the estimated target.

  According to the present invention, the amount of corrosion due to neutralization of reinforced concrete can be estimated easily and accurately.

  Here, in the corrosion amount estimation step in the corrosion amount estimation method according to the present invention, the crack width is divided by the cover thickness with respect to the corrosion amount at the time of occurrence of the crack, and a constant for each deformed reinforcing bar diameter. You may estimate the corrosion amount of the reinforced concrete used as the said estimation object by adding the value which multiplied by.

  Further, in the corrosion amount estimation method according to the present invention, in the corrosion amount estimation step, the corrosion amount of the reinforced concrete to be estimated is further considered in consideration of reinforcing bar interval information regarding the interval between the deformed reinforcing bars of the reinforced concrete to be estimated. May be estimated. By further considering the interval between the deformed reinforcing bars, in other words, the reinforcing bar pitch, the corrosion amount of the reinforced concrete can be estimated more accurately.

  Further, the corrosion amount estimation method according to the present invention is based on the corrosion amount estimated in the corrosion amount estimation step, and a peeling evaluation step for evaluating the risk of peeling of the concrete from the reinforced concrete to be estimated for the corrosion amount. May be further provided. According to the present invention, it is possible to evaluate the risk of concrete peeling.

  In the exfoliation evaluation step, a plurality of criteria for judging the risk of exfoliation of the concrete step by step and the corrosion amount estimated in the corrosion amount estimation step are compared, and the reinforced concrete to be the estimation target You may make it evaluate in stepwise the risk of peeling of concrete from. According to the present invention, it is possible to accurately determine the remaining life and repair time of reinforced concrete.

  Here, the corrosion amount estimation method according to the present invention described above can easily estimate the corrosion amount by the computer executing each step. However, the computer does not necessarily have to execute each step.

  The present invention may be a program for realizing the above-described corrosion amount estimation method. Furthermore, the present invention may be a computer-readable recording medium that records such a program. In this case, the function can be provided by causing a computer or the like to read and execute the program of the recording medium. Note that a computer-readable recording medium is a recording medium that accumulates information such as data and programs by electrical, magnetic, optical, mechanical, or chemical action and can be read from a computer or the like. Say.

Furthermore, this invention can also be specified as a corrosion amount estimation processing apparatus for executing the above-described corrosion amount estimation method. Specifically, the present invention is a corrosion amount estimation device for estimating the corrosion amount of reinforced concrete using deformed reinforcing bars, and a correlation between the corrosion amount of a specimen made of reinforced concrete and a measurement index of cracks of the specimen. Storage unit that stores constant information on constants for each deformed reinforcing bar diameter obtained from the above, information on the amount of corrosion at the time of cracking obtained from the specimen, and cracks in the reinforced concrete for which the amount of corrosion is estimated Information acquisition unit for acquiring crack width information on width, cover thickness information on cover thickness of reinforced concrete to be estimated, and reinforcing bar diameter information on deformed reinforcing bar diameter of reinforced concrete to be estimated; and Information on the amount of corrosion at the time of crack occurrence, crack width information, cover thickness information, and A corrosion amount estimation unit that estimates the corrosion amount of the reinforced concrete to be estimated based on the constant information corresponding to the reinforcing bar diameter information; and an output unit that outputs an estimation result by the corrosion amount estimation unit. .

  Furthermore, this invention can also be specified as a management method of the reinforced concrete using the corrosion amount estimation method mentioned above. Specifically, the present invention positions the step of executing the above-described corrosion amount estimation method as a simple diagnosis step, and further diagnosis is required based on the simple diagnosis step and the diagnosis result of the simple diagnosis step. Based on the detailed diagnosis process that estimates the amount of corrosion in more detail than the simple diagnosis process and the diagnosis result of the simple diagnosis process or the detailed diagnosis process, the life extension is performed when repair is required. It can also be specified as a management method for reinforced concrete including a countermeasure process.

  According to the present invention, appropriate management of reinforced concrete can be performed using the above-described corrosion amount estimation method.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which can estimate the corrosion in the existing reinforced concrete structure using a deformed reinforcing bar more accurately than before can be provided.

The schematic structure of the corrosion amount estimation apparatus which concerns on embodiment is shown. The functional block diagram of the corrosion amount estimation apparatus which concerns on embodiment is shown. The flowchart of the corrosion amount estimation process which estimates the corrosion amount of a reinforced concrete is shown. An example of an input screen is shown. The graph of the amount of corrosion at the time of cracking due to neutralization is shown in the results of the accelerated corrosion test by electric corrosion. Of the results of the corrosion promotion test by electric corrosion, a graph of the amount of corrosion at the time of cracking due to salt damage is shown. An example of the graph regarding the amount of corrosion and the crack width is shown. An example of the graph regarding the reciprocal number of the corrosion amount per unit crack width and cover thickness is shown. An example of the database regarding constant information is shown. An example of a corrosion level judgment table is shown. The other example of an input screen is shown. The procedure for the management method of reinforced concrete using the method for estimating the amount of corrosion is shown. Degradation level judgment index is shown. The shape and dimension of the test body in a 1st test are shown. The state of electrolytic corrosion of the specimen in the first test is shown. The shape and dimension of the test body in the second test are shown (@ 50). The shape and dimensions of the specimen in the second test are shown (@ 75). The shape and dimension of the test body in the second test are shown (@ 100). The state of the peeling method in the second test is shown. The graph of the corrosion amount at the time of the crack generation in a 2nd test is shown. The relationship between the crack width and the reinforcing bar pitch in the second test is shown. The relationship between the average corrosion amount of the main reinforcement and the peeling stress is shown.

  Next, an embodiment of a corrosion amount estimation method according to the present invention will be described with reference to the drawings. In the following description, a case where the corrosion amount estimation method is realized by a corrosion amount estimation device will be described as an example. A management method for reinforced concrete using the corrosion amount estimation method according to the present invention will also be described.

[First embodiment]
<Configuration>
FIG. 1 shows a schematic configuration of a corrosion amount estimation apparatus (hereinafter also simply referred to as an estimation apparatus) 5 according to an embodiment. FIG. 2 shows a functional block diagram of the estimation device 5. The estimation device 5 includes a general-purpose computer, and includes a housing 1 that stores the control unit 10, a display unit 2 such as a display, an operation unit 3 such as a pointing device and a keyboard, and an interface 4 that can be connected to an external device.

  The display unit 2 is, for example, a liquid crystal display device, a plasma display panel, a CRT (Cathode Ray Tube), an electroluminescence panel, or the like. The operation unit 3 is a computer input device, and includes, for example, a keyboard and a pointing device. The keyboard transmits an electrical signal corresponding to the input key to a keyboard controller (not shown) of the keyboard in response to a user input operation. The keyboard controller transmits a code corresponding to the electrical signal to the CPU 11. In response to a user input operation, the CPU 11 displays a character cursor indicating a character input destination on the screen and moves it on the screen. The pointing device detects a user operation and transmits an operation signal to a pointing device control apparatus (not shown) (for example, a mouse controller not shown or the interface 4). The device driver of the CPU 11 displays a pointer on the screen on the display unit 2 and moves it on the screen based on an operation signal from the pointing device control device. The interface 4 may be a serial interface such as USB, or PCI (Peripheral Component Interconnect), ISA (Industry Standard Architecture), EISA (Extended ISA), ATA (AT Attach EID, E13 Any of parallel interfaces such as Computer System Interface may be used.

  The control unit 10 includes a CPU (central processing unit) 11, a memory 12, an information acquisition unit 13, an estimation unit 14, a peeling evaluation unit 15, an output unit 16, and a storage unit 17. The CPU 11 is connected to each hardware such as the storage unit 17 described above via a bus. The CPU 11 controls hardware such as the storage unit 17 and executes predetermined processing according to a control program stored in the memory 12, for example.

  The memory 12 includes a volatile RAM (Random Access Memory) and a nonvolatile ROM (Read Only Memory). The ROM includes a rewritable semiconductor memory such as a flash memory, an EPROM (Erasable Programmable Read-Only Memory), and an EEPROM (Electrically Erasable Programmable Read-Only Memory).

The storage unit 17 can be configured by a hard disk drive (hereinafter referred to as HDD) or a semiconductor memory. The memory | storage part 17 memorize | stores the constant information regarding the constant for every deformed reinforcing bar diameter calculated | required from the correlation of the corrosion amount of deformed reinforcing bars and the crack measurement index of reinforced concrete, for example.

  The information acquisition unit 13 is information on the amount of corrosion at the time of occurrence of cracking of a specimen made of reinforced concrete when cracking occurs, information on the width of cracking on the crack width of reinforced concrete to be estimated, and the cover thickness of the reinforced concrete to be estimated. The cover thickness information on the reinforced concrete and the reinforced concrete diameter information on the deformed reinforced concrete diameter of the reinforced concrete to be estimated are acquired. These pieces of information can be input via the operation unit 3, and as a result, the information acquisition unit 13 can acquire each piece of information.

  The estimation unit 14 is obtained by the information acquisition unit 13, the amount of corrosion at the time of crack occurrence, the crack width information, the cover thickness information, and the constant information stored in the storage unit 17 specified by the reinforcing bar diameter information. Based on, the amount of corrosion of the reinforced concrete to be estimated is estimated.

  The output unit 16 outputs the estimation result calculated by the estimation unit 14, that is, the corrosion amount of reinforced concrete. Specifically, the output unit 16 causes the display unit 2 to display an estimation result, for example. The output unit 16 can also output to the outside of the estimation device 5 via the interface 4.

<Corrosion amount estimation processing>
FIG. 3 shows a flowchart of a corrosion amount estimation process (hereinafter also simply referred to as an estimation process) for estimating the corrosion amount of reinforced concrete. In step S01, the information acquisition unit 13 acquires information on the amount of corrosion at the time of crack occurrence, crack width information, cover thickness information, and reinforcing bar diameter information. Corrosion amount information, crack width information, and cover thickness information when cracks are generated are input via the operation unit 3. The constant information is acquired by inputting reinforcing bar diameter information via the operation unit 3.

  FIG. 4 shows an example of the input screen. Such an input screen is displayed on the display unit 2. The tester or the like inputs necessary information via the operation unit 3. The input screen shown in FIG. 4 has a crack occurrence corrosion amount input area, a cover thickness input area, a crack width input area, a reinforcing bar diameter input area, a corrosion cause input area, a decision button, and a reset button. The reinforcing bar diameter (reinforcing bar diameter information) can be selected from D13 and D16, for example. Further, the cause of corrosion can be selected from salt damage, neutralization, salt damage + neutralization. Thereafter, an estimation process is started by selecting a decision button. When the reset button is selected, the input information is initialized.

  Here, various information acquired by the information acquisition unit 13, in other words, parameters input via the operation unit 3 and necessary for estimation processing will be described.

The amount of corrosion when cracks occur is the amount of corrosion when cracks occur, and can be obtained in advance by a corrosion acceleration test using electric corrosion. FIG. 5A is a graph of the amount of corrosion at the time of occurrence of cracks due to neutralization among the corrosion acceleration test results by electric corrosion, and FIG. 5B is the corrosion at the time of occurrence of cracks by salt damage among the results of corrosion acceleration tests by electric corrosion. It is a graph of quantity. In any graph, the horizontal axis represents the cover thickness and the reinforcing bar diameter (reinforcing bar diameter), and the vertical axis represents the amount of corrosion when cracking occurs. As shown in FIG. 5A, for example, the corrosion amount Q ₀ when cracking due to neutralization occurs is about 15 mg / cm ² with a cover thickness of 15 mm and a reinforcing bar diameter D13, and the standard deviation σ is about 9 mg / cm ^2. cm ² . As shown in FIG. 5B, for example, the corrosion amount Q ₀ when cracking occurs due to salt damage is about 20 mg / cm ² when the cover thickness is 15 mm and the reinforcing bar diameter D13, and the standard deviation σ is about 5 mg. / Cm ² . The amount of corrosion at the time of crack occurrence may be directly input via the operation unit 3, or may be automatically selected when a reinforcing bar diameter and a cover thickness are input. In this embodiment, the diameter of a reinforcing bar means the diameter of a deformed reinforcing bar. The cover thickness means the distance from the reinforcing bar to the surface of the specimen.

  The crack width information is information relating to the width of the crack, and in the present embodiment means the maximum crack width. Instead of the crack width information, surface displacement amount information regarding the surface displacement amount may be used. The amount of surface displacement means the amount of deformation of cracks existing on the surface of reinforced concrete.

  The constant information is a constant given for each deformed reinforcing bar diameter, and can be obtained from the correlation between the corrosion amount of the deformed reinforcing bar and the measurement index of cracks in the reinforced concrete. Here, FIG. 6 is an example of a graph relating to the corrosion amount and crack width. In FIG. 6, the horizontal axis represents the maximum crack width, the vertical axis represents the amount of corrosion, and FIG. 6 relates to a graph of the amount of corrosion when the reinforcing bar diameter is D13 and the cause of corrosion is neutralization. In FIG. 6, there are three regression lines (the cover thickness is 15 mm (indicated by C15 in FIG. 6), the cover thickness is 30 mm (indicated by C30 in FIG. 6), and the cover thickness is 45 mm (indicated by C45 in FIG. 6)). It is shown. For example, a regression line relating to a cover thickness of 15 mm corresponds to a regression equation in which the average value of the amount of corrosion at the time of occurrence of cracks (marked with ●) in FIG. 5A is a y-intercept. The slope of the regression equation in FIG. 6 is calculated by the amount of corrosion when the crack width widens by 1 mm. In addition, as shown in FIG. 6, a proportional relationship can be confirmed between the corrosion amount and the crack width.

  FIG. 7 is an example of a graph relating to the amount of corrosion per unit crack width and the reciprocal of the cover thickness. In FIG. 7, the horizontal axis represents the reciprocal of the cover thickness, and the vertical axis represents the amount of corrosion per unit crack width, in other words, the slope of the regression line in FIG. The regression line shown in FIG. 7 is a case where the reinforcing bar diameter is D13, and is calculated from the slopes of the three regression lines shown in FIG. The slope of the regression line shown in FIG. 7 corresponds to constant information. That is, constant information in the case where the rebar diameter is D13 and the cause of corrosion is neutralization is 8104 (about 8100). The constant information is calculated for each reinforcing bar diameter and the cause of corrosion by the procedure described above, and stored in the storage unit 17 in advance. FIG. 8 shows an example of a database related to constant information. The database shown in FIG. 8 stores the constant information of each of the reinforcing bar diameter D13 and the reinforcing bar diameter D16 because the cause of corrosion is due to neutralization.

If acquisition of each information by the information acquisition part 13 is completed, it will progress to step S02. In step S02, the estimation unit 14 is based on the crack generation corrosion amount information, crack width information, cover thickness information, and constant information specified from the reinforcing bar diameter information acquired by the information acquisition unit 13. Thus, the amount of corrosion of the reinforced concrete to be estimated is estimated. Specifically, the amount of corrosion is estimated from the crack width by Equation 1. Equation 1 corresponds to the regression equation shown in FIG. When the corrosion amount is estimated, the process proceeds to step S03.
ΔQ = Q ₀ + a · w / C Equation 1
ΔQ: Corrosion amount (mg / cm ² )
C: Cover thickness (mm)
w: Crack width (mm)
Q ₀ : Corrosion amount when cracking occurs Corrosion due to neutralization: Q ₀ = 15 mg / cm ²
In the case of corrosion due to salt: Q ₀ = 20 mg / cm ²
a: Constant determined by the rebar diameter In the case of crack width, 8100 for D13 and 5600 for D16

  In step S03, the peeling evaluation unit 15 determines the corrosion level of the estimated corrosion amount. Here, FIG. 9 shows an example of the corrosion level determination table. The corrosion level determination table shown in FIG. 9 is stored in the storage unit 13, and the deterioration state is defined in advance according to the amount of corrosion. The peeling evaluation unit 15 accesses the corrosion level determination table stored in the storage unit 17 and determines the corrosion level based on the estimated corrosion amount. When the determination of the corrosion level is completed, the process proceeds to step S04. Note that the process of step S03 may be omitted and a simpler process may be performed.

  In step S04, the output unit 16 outputs the determination result of the corrosion level. For example, if the corrosion level is determined to be level A, the output unit 16 causes the display unit 2 to display “level A: no problem at all with minute cracks” as a message. In addition, when the process of step S03 is omitted, the output unit 16 can display the estimated corrosion amount on the display unit 2. When the output of the determination result of the corrosion level is completed, the corrosion amount estimation process ends.

<Modification of corrosion amount estimation processing>
Next, a modification of the corrosion amount estimation process will be described. In the corrosion amount estimation processing according to the modified example, the corrosion amount is estimated in consideration of the reinforcing bar pitch. Specifically, in step S01 of the corrosion amount estimation process shown in FIG. 3, the information acquisition unit 13 further acquires reinforcing bar interval information (rebar pitch) regarding the interval between reinforcing bars. Here, FIG. 10 shows another example of the input screen. The input screen shown in FIG. 10 further has a reinforcing bar pitch input area, and a reinforcing bar pitch can be selected via the operation unit 3. The reinforcing bar pitch can be selected in the range of 50 mm (@ 50) to 150 mm (@ 150). In addition, you may enable it to input a numerical value directly.

Further, in step S02, the estimation unit 14 acquires the cracking corrosion amount information, crack width information, cover thickness information, reinforcing bar interval information (reinforcing bar pitch), and reinforcing bar diameter acquired by the information acquiring unit 13. Based on the constant information specified by the information, the amount of corrosion of the reinforced concrete to be estimated is estimated. Specifically, the amount of corrosion is estimated from the crack width by Equation 2. In addition, the applicable range of Formula 2 is the reinforcing bar diameters D13 to D16 and the reinforcing bar pitch @ 50 to 150.
ΔQ = Q ₀ + a · w · (@ − 50) / 100 / C Equation 2
ΔQ: Corrosion amount (mg / cm ² )
C: Cover thickness (mm)
w: Crack width (mm)
Q ₀ : Corrosion amount when cracking occurs Corrosion due to neutralization: Q ₀ = 15 mg / cm ²
In the case of corrosion due to salt: Q ₀ = 20 mg / cm ²
a: Constant determined by the rebar diameter In the case of crack width, 8100 for D13 and 5600 for D16

In step S03, as in the corrosion amount estimation process, the peeling evaluation unit 15 determines the corrosion level of the estimated corrosion amount. Instead of determining the corrosion level, the peeling evaluation unit 15 may determine whether or not the estimated amount of corrosion exceeds a predetermined peeling reference value. The peeling reference value can be set to 40 mg / cm ² , for example. In step S04, the output unit 16 outputs whether the determination result of the corrosion level or the estimated amount of corrosion exceeds a predetermined peeling reference value. For example, when it is determined that the estimated amount of corrosion exceeds a predetermined peeling reference value, the output unit 16 displays a message “Estimated amount of corrosion defined in advance as a message on the display unit 2. “The peeling standard value is exceeded.” Is displayed. Thus, the muscle corrosion amount estimation process according to the iron modification example is completed.

<Effect>
According to the corrosion amount estimation apparatus 5 according to the embodiment described above, when estimating the corrosion amount, by considering constant information regarding the constant for each deformed bar diameter, the existing reinforced concrete using the deformed bar from the crack width. The amount of corrosion in the structure can be easily and accurately evaluated. Moreover, according to the corrosion amount estimation processing according to the modification, it is possible to estimate the corrosion by changing the reinforcing bar pitch, and it is possible to evaluate the corrosion amount in the existing reinforced concrete structure more accurately.

<How to use>
Next, a method for utilizing the above-described corrosion amount estimation method will be described. FIG. 11 shows the procedure of a reinforced concrete management method utilizing the corrosion amount estimation method. In step S11, the above-described corrosion amount estimation processing (step S01 to step S04) is performed as a simple diagnostic process. In the simple diagnosis process, it is only necessary to perform deterioration diagnosis and remaining life evaluation by an economical method in a short time without damaging the housing as much as possible. Therefore, when corrosion cracking has occurred, it is preferable to perform a corrosion amount estimation process, but other evaluation methods may be used. For example, the corrosion amount is calculated by the method described in Japanese Patent No. 4108568 (Patent Document 1) instead of or in addition to the steps 01 and 02 in the above-described corrosion amount estimation processing. Also good. In the simple diagnostic process, non-destructive inspection is preferred, and the neutralization depth is micro-destructive inspection using a small diameter drill. The deterioration diagnosis and the remaining life evaluation method are based on the survey results, calculating the remaining neutralization, the corrosion probability, and the amount of corrosion, and estimating the deterioration level after the target service period of the building (for example, after 30 years). Can be determined. In the simple diagnosis process, it is preferable that the evaluation result is determined with a margin in consideration of inspection accuracy and sampling variation. When the simple diagnosis process ends, the process proceeds to step S12.

  In step S12, it is determined whether or not to perform a detailed diagnosis process. In the simple diagnosis process, if a determination result of level A (no problem at all with minute cracks) or level B (cracks occur in various places) is output, the remaining life is sufficient (step S13). ). In addition, in the simple diagnosis process, the judgment result of level C (there is a float and there are peeling in various places and there is a problem in usability) or level D (the cross section of the reinforcing bar is missing and there is a problem in the structural performance of the member) is output. If yes, the process proceeds to the detailed diagnosis process (step S14) or the life extension countermeasure process (step S16).

  In the simple diagnosis process, neutralization residue, corrosion probability, and corrosion amount may be calculated. In this case, for example, whether the detailed diagnosis process is performed based on the degradation level determination index shown in FIG. It may be determined whether or not. FIG. 12 shows the determination index of the deterioration level.

  In step S14, a detailed diagnosis process is performed in which the amount of corrosion is estimated in more detail than the simple diagnosis process. In the detailed diagnosis process, a detailed investigation is performed on a wide range by destructive inspection such as core boring and hulling investigation, and nondestructive inspection such as natural potential and polarization resistance. As a result, the neutralization residue, the corrosion probability, and the corrosion amount are calculated, and the deterioration level is determined based on, for example, the deterioration level determination index shown in FIG. When the detailed diagnosis process ends, the process proceeds to step S15.

  In step S15, it is determined whether or not to perform a life prolonging countermeasure process. In the detailed diagnosis process, if the determination result of level A (no problem at all with minute cracks) or level B (cracks occur in various places) is output, the remaining life is sufficient (step S13). ). In addition, in the detailed diagnosis process, the determination result of level C (there is a float and there are peeling in various places and there is a problem in usability) or level D (the cross section of the reinforcing bar is missing and there is a problem in the structural performance of the member) is output. If yes, the process proceeds to the life extension countermeasure process (step S16) or the study on rebuilding (step S17).

  In step S16, life extension measures are taken. Specifically, application of repair / repair technology and durability recovery technology will be examined, and approximate repair costs will be calculated. Thereafter, a determination is made as to whether or not there is a cost merit, and if there is a cost merit, repair or the like is performed. On the other hand, when there is no cost merit, it progresses to step S17 and examination about rebuilding etc. is performed.

As explained above, by using the method for estimating the amount of corrosion, it is possible to easily determine whether there is a sufficient remaining life or whether it is necessary to take measures to extend the life. Management can be performed appropriately.

<Test>
Next, the test performed previously will be described.

[First test]
In a test to confirm the relationship between the amount of corrosion and the crack width (hereinafter also referred to as the first test), the appearance of the concrete surface, that is, the occurrence of cracks, in the process of corrosion of the reinforcing bar and deterioration of the structure, The purpose of this study was to examine a method for simply evaluating the degree of progress of corrosion.

(Outline of the first test)
Materials include ordinary Portland cement, Kashima land sand (coarse grain ratio: 2.65, surface dry specific gravity: 2.62 g / cm ³ , water absorption: 2.13%), Iwafune sandstone (coarse grain ratio: 6.64) , Surface dry specific gravity: 2.66 g / cm ³ , water absorption: 0.88%), AE water reducing agent standard type was used. Commercial artificial seawater was used to adjust the chloride ion content. Table 1 shows the concrete blending and test results. The test factors and levels are shown in Table 2. The rebar diameter, the cover thickness, and deterioration factors (neutralization, salt damage) were used as factors.

The shape and dimensions of the test specimen are shown in FIG. Conductor cords were attached to the reinforcing bars and coated with epoxy resin. Insulation tape was wrapped around the reinforcing bars at the intersection of the reinforcing bars. After the concrete was cast and demolded, resin mortar was placed on four surfaces other than the test surface. In-air curing was performed until the age of 28 days. Thereafter, the neutralization test specimen neutralized the concrete to the depth of cover under a high-concentration carbon dioxide atmosphere. As the salt damage test specimen, concrete containing 2.4 kg / m ³ of chloride ions was used.

  In a room at 20 ° C. and a humidity of 95% or more, as shown in FIG. The salt damage test specimens started electric corrosion from the age of 50 days, and the neutralized specimens started electric corrosion after the neutralization treatment of all the specimens was completed (age 150 days). The cathode placed on the reinforced concrete surface was shaped so that surface cracks could be visually observed during electrolytic corrosion, and an electrolyte was used to reduce the contact resistance between the electrode and concrete. There were 2 to 4 types of specimens in terms of accumulated current.

At the time of electrolytic corrosion, the amount of energization and the crack width on the surface were recorded. After the completion of the electric corrosion, the reinforcing bars were taken out from the specimen, and diammonium citrate 10% and 2-mercaptobenzothiazole 1
After being immersed in a 50 ppm solution for 1 hour, it was removed with a wire brush and the amount of corrosion with respect to the corrosion zone was determined.

(Result of the first test)
FIG. 5A shows a graph of the amount of corrosion at the time of occurrence of cracks due to neutralization among the results of the corrosion promotion test by electric corrosion. FIG. 5B shows a graph of the amount of corrosion at the time of cracking due to salt damage among the results of the corrosion acceleration test by electric corrosion. As shown in FIG. 5A, for example, the corrosion amount Q ₀ when cracking due to neutralization occurs is about 15 mg / cm ² with a cover thickness of 15 mm and a reinforcing bar diameter D13, and the standard deviation σ is about 9 mg / cm ^2. It was confirmed to be cm ² . As shown in FIG. 5B, for example, the corrosion amount Q ₀ when cracking occurs due to salt damage is about 20 mg / cm ² when the cover thickness is 15 mm and the reinforcing bar diameter D13, and the standard deviation σ is about 5 mg. / Cm ² was confirmed.

  As described above, FIG. 6 is an example of a graph regarding the corrosion amount and the crack width. FIG. 6 shows three regression lines. For example, a regression line relating to a cover thickness of 15 mm corresponds to a regression equation in which the average value of the amount of corrosion at the time of occurrence of cracks (marked with ●) in FIG. In any regression line, it was confirmed that the amount of corrosion tends to increase with increasing cracks.

FIG. 7 is an example of a graph relating to the amount of corrosion per unit crack width and the reciprocal of the cover thickness. As shown in FIG. 7, it was confirmed that the amount of corrosion per unit crack width, in other words, the slope of the regression line in FIG. 6 and the reciprocal of the cover thickness are in a proportional relationship. Therefore, ΔQ: Corrosion amount (mg / cm ² ), C: Cover thickness (mm), w: Crack width (mm), Q ₀ : Corrosion amount at the time of crack occurrence is ΔQ = Q ₀ + a · w It was confirmed that the relational expression of / C holds.

[Second test]
The test for confirming the applicability of the corrosion amount application formula when the rebar pitch is different and the test for evaluating the risk of peeling / peeling of cover concrete (hereinafter also referred to as the second test) The purpose of this study was to confirm the applicability of the corrosion amount application formula when the pitch is different, and the evaluation method for the risk of peeling and peeling off of the cover concrete.

(Outline of the second study)
Table 3 shows the concrete blending and test results. The material used was the same as the test for confirming the relationship between the amount of corrosion and the crack width. The preparation was mixed with a chloride ion amount of 2.4 kg / m ³ .

The shape and dimensions of the specimen are shown in FIGS. 15A, 15B, and 15C. The reinforcing bar was D16, the cover thickness was 30 mm, and the reinforcing bar pitch was 50 mm, 75 mm, and 100 mm. A cord for energization was attached to the reinforcing bar, and the end was coated with poxy resin. A 200 mm thick slab was simulated to cast concrete, and the main bar on the lower surface was subjected to electrolytic corrosion as a test object. Specimens were prepared each two bodies so that the amount of corrosion of the target is ^{40mg / cm 2, 60mg / cm} 2. For comparison, a test specimen that was not subjected to electrolytic corrosion was also created. In addition, in this test body, the resin mortar was not installed in order to observe the crack of a small surface.

  The electrolytic corrosion method was the same as that in the first test, and one DC stabilized power source was used for each main bar. Electric corrosion was started from the age of 50 days.

  At the time of electrolytic corrosion, the amount of energization, the crack width on the small edge, and the crack width on the surface were measured with a crack gauge and a microscope. After completion of electrolytic corrosion, ink is infiltrated from the cracks on the small mouth surface for the purpose of confirming the cracked area, and then the main reinforcement is loaded on the reaction bar as shown in FIG. Was measured. The removed reinforcing bars were immersed in a solution of 10% diammonium citrate and 150 ppm 2-mercaptobenzothiazole for 1 hour, and then removed with a wire brush, and the weight loss was measured.

(Result of second test)
FIG. 17 shows a graph of the amount of corrosion when cracks occur in the second test. FIG. 18 shows the relationship between the crack width and the reinforcing bar pitch in the second test. As shown in FIG. 17, cracks did not occur on the upper surface when the reinforcing bar pitch was 50 mm, and cracks occurred on the upper surface when the reinforcing bar pitch was 75 mm and the reinforcing bar pitch was 100 mm. Therefore, it was confirmed that the amount of corrosion can be estimated from the crack width when the rebar pitch is 75 mm or more. Further, as shown in FIG. 18, when the reinforcing bar pitch is narrowed, the surface displacement is reduced even with the same amount of corrosion, and it was confirmed that the reinforcing bar pitch and the surface displacement are in a proportional relationship. In the first test, it was confirmed that the amount of corrosion per unit crack width, in other words, the slope of the regression line in FIG. 6 and the reciprocal of the cover thickness were in a proportional relationship. It was confirmed that the surface displacement is proportional. Therefore, when considering the reinforcing bar pitch, ΔQ: Corrosion amount (mg / cm ² ), C: Cover thickness (mm), w: Crack width (mm), Q ₀ : Corrosion amount when cracking occurs, @ Reinforcing bar pitch Is a relational expression of ΔQ = Q ₀ + a · w (@ − 50) / 100 / C.

FIG. 19 shows the relationship between the average corrosion amount of the main bars and the peeling stress. Peeling stress also those sound was 0.6 N / mm ² approximately, with respect to the test value 2.6 N / mm ² of the split裂引tension strength of the concrete base material, it was confirmed that about 1/4 degree and smaller. According to the second test, it was confirmed that when the corrosion amount was up to about 40 mg / cm ² with respect to a healthy one, the decrease in the peeling stress was slight. On the other hand, it was confirmed that when corrosion progresses to about 60 mg / cm ² , the peel stress decreases to about 1/3. Therefore, under the conditions of the reinforcing bar diameter D16 and the cover thickness of 30 mm, the corrosion amount of 60 mg / cm ² is the limit of usability, and the reference value is preferably 40 mg / cm ² with a slight decrease in peeling stress. Was confirmed.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these, and can include combinations thereof as much as possible.

DESCRIPTION OF SYMBOLS 1 ... Housing 2 ... Display part 3 ... Operation part 4 ... Interface 5 ... Estimation apparatus 10 ... Control part 11 ... CPU
DESCRIPTION OF SYMBOLS 12 ... Memory 13 ... Information acquisition part 14 ... Calculation part 15 ... Peeling evaluation part 16 ... Output part 17 ... Memory | storage part

Claims (8)

A corrosion amount estimation method for estimating the corrosion amount of reinforced concrete using deformed reinforcing bars,
A constant information acquisition step for acquiring constant information on a constant for each deformed reinforcing bar diameter obtained from a correlation between a corrosion amount of a specimen made of reinforced concrete and a measurement index of a crack of the specimen;
Information on the amount of corrosion at the time of occurrence of cracks obtained from the specimen, information on the amount of cracks on the crack width of the reinforced concrete subject to estimation of the amount of corrosion, and cover on the cover thickness of the reinforced concrete subject to estimation Corrosion amount estimation step for estimating the corrosion amount of the reinforced concrete to be estimated based on the thickness information and the constant information specified by the reinforcing bar diameter information regarding the deformed reinforcing bar diameter of the reinforced concrete to be the estimation target;
A corrosion amount estimation method comprising: The amount of corrosion information at the time of crack occurrence includes neutralization corrosion amount information due to neutralization of reinforced concrete, and salt damage corrosion amount information due to salt damage,
The constant information includes neutralization constant information due to neutralization of reinforced concrete, and salt damage constant information due to salt damage,
In the corrosion amount estimation step, when the corrosion of the deformed reinforcing bar in the reinforced concrete to be estimated is due to the neutralization of the reinforced concrete, the neutralized corrosion amount information is used as the cracking corrosion amount information, and the constant information is used as the constant information. The amount of corrosion of the reinforced concrete to be estimated is estimated using the neutralization constant information, and when the corrosion of the deformed reinforcing bar in the reinforced concrete to be estimated is caused by salt damage, the salt damage as the corrosion amount information at the time of crack occurrence The corrosion amount estimation method according to claim 1, wherein corrosion amount information is used and the corrosion amount of the reinforced concrete to be estimated is estimated using the salt damage constant information as the constant information.   In the corrosion amount estimating step, the estimation target is obtained by adding a value obtained by dividing the crack width by the cover thickness and multiplying by a constant for each deformed reinforcing bar diameter with respect to the corrosion amount at the time of occurrence of the crack. The corrosion amount estimation method according to claim 1, wherein the corrosion amount of reinforced concrete is estimated.   The corrosion amount estimation step further estimates the corrosion amount of the reinforced concrete as the estimation target by further considering rebar interval information regarding the interval between the deformed reinforcing bars of the reinforced concrete as the estimation target. The corrosion amount estimation method according to item 1.   5. The peeling evaluation step according to claim 1, further comprising a peeling evaluation step for evaluating a risk of peeling of concrete from reinforced concrete to be estimated for the corrosion amount based on the corrosion amount estimated in the corrosion amount estimation step. The corrosion amount estimation method according to item 1.   In the exfoliation evaluation step, a plurality of judgment criteria for judging the risk of delamination of the concrete step by step and the amount of corrosion estimated in the amount of corrosion estimation step are compared, and from the reinforced concrete to be estimated. The corrosion amount estimation method according to claim 5, wherein the risk of concrete peeling is evaluated step by step. A corrosion amount estimation device for estimating the corrosion amount of reinforced concrete using deformed reinforcing bars,
A storage unit for storing constant information on constants for each deformed reinforcing bar diameter obtained from a correlation between a corrosion amount of a specimen made of reinforced concrete and a measurement index of cracks of the specimen;
Information on the amount of corrosion at the time of occurrence of cracks obtained from the specimen, information on the amount of cracks on the crack width of the reinforced concrete subject to estimation of the amount of corrosion, and cover on the cover thickness of the reinforced concrete subject to estimation Information acquisition unit for acquiring thickness information and reinforcing bar diameter information related to the deformed reinforcing bar diameter of the reinforced concrete to be estimated;
The estimation target based on the crack occurrence corrosion amount information, the crack width information, the cover thickness information, and the constant information corresponding to the reinforcing bar diameter information acquired by the information acquisition unit. Corrosion amount estimation part for estimating the corrosion amount of reinforced concrete,
An output unit for outputting an estimation result by the corrosion amount estimation unit;
Corrosion amount estimation device comprising: A method for managing reinforced concrete using deformed reinforcing bars,
A simple diagnostic process for executing the corrosion amount estimation method according to claim 1,
Based on the diagnosis result of the simple diagnosis step, a detailed diagnosis step for performing the estimation of the amount of corrosion in more detail than the simple diagnosis step, which is executed when further diagnosis is required,
A method for managing reinforced concrete, comprising: a life prolonging measure step, which is executed when repair is required based on a diagnosis result of the simple diagnosis step or the detailed diagnosis step.

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