Concrete compressive strength measurement method and concrete compressive strength measurement system

Abstract

To provide a concrete compression strength measuring method and the like that can simply and accurately measure the compression strength of hardened concrete.SOLUTION: A concrete compression strength measuring system 1 comprises: a measuring device 3 that is attached to an electric screwdriver 2; and an analyzer 5 that acquires and analyzes measurement data obtained through measurement performed by the measuring device 3. The measuring device 3 measures rotational strain generated when an external thread 4 is screwed into a concrete member 10 by using the electric screwdriver 2, and outputs the rotational strain to the analyzer 5 as the measurement data. The analyzer 5 acquires the measurement data, determines torque reaction based on the measurement data while over torque is generated, and estimates the compression strength of the concrete member 10 based on a relation between the torque reaction and the compression strength of concrete.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention provides a method for measuring concrete compressive strength, and Concrete Compressive Strength Measurement System Mu The present invention relates to a technique for measuring the compressive strength of concrete. [Background technology]

[0002] There are several methods for determining the compressive strength of concrete, including destructive methods, in which core specimens are extracted from concrete structures and compressed to measure their strength, and non-destructive strength estimation methods, in which ultrasonic waves or impact elastic waves are used to estimate the strength inside the structure. However, destructive methods have problems such as damaging the structure and making them unsuitable for extracting multiple cores from a single structure, and in the case of small-diameter cores, the results can differ significantly from the actual strength. Furthermore, they require a lot of labor, time, and cost. Ultrasonic and impact elastic wave methods, for example, require prior calibration using concrete specimens of the same composition to determine the quantitative relationship between strength and estimated indices, which is cumbersome. Furthermore, accuracy is significantly affected by quality differences between the surface and interior, as well as the age of the material, resulting in poor overall accuracy.

[0003] Additionally, various minimally destructive testing methods have been proposed, including the penetration test, pin pull-out test, core tensile destructive test, scratch width test, and drilling resistance method. These test methods have had problems such as the need to determine the relationship between penetration resistance and compressive strength in advance using concrete specimens of the same mix, they can only be applied to specimens with a mortar finish, measurement accuracy is affected by aggregates, and they are affected by the state of surface deterioration, as well as poor measurement accuracy overall.

[0004] Patent Document 1 proposes a method for determining concrete strength based on the relationship between torque value and compressive strength. This method involves embedding a bolt into concrete, with a test bolt having a concrete drill welded to the tip and threaded thereon so that the bolt can be advanced and retreated, and threading the bolt into a fixing nut attached to a fixing rebar, bringing the tip of the concrete drill into contact with the poured concrete, and rotating the test bolt with a torque wrench at predetermined hardening time intervals to advance the bolt and measure the torque value, and determining the concrete strength based on a previously prepared relationship between torque value and compressive strength. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Publication No. 56-160636 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the method disclosed in Patent Document 1 aims to determine when to remove the concrete formwork, and requires that a concrete drill be welded to the tip of a bolt and set together with a nut before pouring the concrete, so it cannot be applied to hardened concrete.

[0007] The present invention has been made in view of the above problems, and an object of the present invention is to provide a concrete compressive strength measuring method and the like that can measure the compressive strength of hardened concrete easily and with high accuracy. [Means for solving the problem]

[0008] A first invention for solving the above-mentioned problems is a method for measuring compressive strength of concrete, including the steps of: using an electric screwdriver having a function of maintaining a constant rotational speed to screw a male screw into a concrete member; measuring data using a measuring device to determine the torque reaction force generated when the male screw is being screwed; and estimating the compressive strength of the concrete member using an analyzing device by determining the torque reaction force based on the measurement data obtained while the head of the male screw is in contact with the concrete member and over-torque is occurring.

[0009] According to the first aspect of the present invention, a concrete compressive strength measurement method uses a measuring device to measure data for determining the torque reaction force generated when a male screw is driven into a concrete member using an electric screwdriver with a function for maintaining a constant rotational speed. The analysis device then calculates the torque reaction force based on the measurement data obtained while the head of the male screw is in contact with the concrete member, generating overtorque, and estimates the compressive strength of the concrete member. This makes it possible to estimate the compressive strength of concrete through the simple task of driving a male screw into a concrete member with an electric screwdriver. Measurements can be performed directly on the target concrete structure, eliminating the need for prior measurements using cores or test specimens with the same composition, as in conventional methods. Furthermore, damage to the measurement site is limited to the drilled holes caused by the screw, making repairs easy.

[0010] In the estimation step of the first aspect of the present invention, a time integral value of the torque reaction force while the over-torque is occurring is calculated, and the compressive strength of the concrete member is estimated based on the calculated time integral value. As a result, the compressive strength of the concrete is estimated based on the relationship between the time integral value of the torque reaction force occurring in the concrete member in the over-torque section and the compressive strength, an accurate estimation result can be obtained without requiring many parameters.

[0011] Furthermore, it is desirable that the measurement data be data on the amount of rotational strain transmitted from the concrete member to the electric screwdriver. By measuring the amount of rotational strain transmitted to the electric screwdriver with a measuring device, the compressive strength of the concrete to be evaluated can be determined, making the measurement easy and reducing labor, time, and costs.

[0012] It is also desirable to further include a step in which the analysis device sets a section in the measurement data where the over-torque occurs. Also, it may further include a step in which an operator specifies a section in the measurement data where the over-torque occurs. This makes it possible to appropriately set the over-torque section.

[0013] A second invention is a concrete compressive strength measurement system comprising a measuring device and an analyzing device, wherein the measuring device comprises: a measuring unit that measures measurement data to determine the torque reaction force generated when a male screw is being screwed into a concrete member using an electric screwdriver having the function of maintaining a constant rotational speed; an interface that outputs the measurement data to the analyzing device; and a fixing unit that fixes the measuring unit and the interface to the drill of the electric screwdriver, and the analyzing device comprises: a measurement data acquiring unit that acquires the measurement data measured by the measuring device; and an estimation unit that determines the torque reaction force based on the measurement data, including the measurement data measured while the head of the male screw is in contact with the concrete member and over-torque is occurring, and the analyzing device estimates the compressive strength of the concrete member.

[0014] According to the second invention of the concrete compressive strength measurement system, a measuring device is used to measure data for determining the torque reaction force generated when a male screw is driven into a concrete member using an electric screwdriver with a function to maintain a constant rotational speed. The analysis device then calculates the torque reaction force based on the measurement data obtained while the head of the male screw is in contact with the concrete member, generating overtorque, and estimates the compressive strength of the concrete member. This makes it possible to estimate the compressive strength of concrete through the simple task of driving a male screw into a concrete member with an electric screwdriver. Measurements can be performed directly on the target concrete structure, eliminating the need for prior measurements using cores or test specimens with the same composition, as in conventional methods. Furthermore, damage to the measurement site is limited to the drilled hole caused by the screw, making repairs easy.

[0015] In the second aspect of the present invention, the estimation unit calculates a time integral of the torque reaction force while the over-torque is occurring, and estimates the compressive strength of the concrete member based on the calculated time integral. This allows the compressive strength of the concrete to be estimated based on the relationship between the time integral of the torque reaction force occurring in the concrete member in the over-torque section and the compressive strength, making it possible to obtain accurate estimation results without requiring many parameters.

[0016] Furthermore, it is desirable that the measurement data be data on the amount of rotational strain transmitted from the concrete member to the electric screwdriver. By measuring the amount of rotational strain transmitted to the electric screwdriver with a measuring device, the compressive strength of the concrete to be evaluated can be determined, making the measurement easy and reducing labor, time, and costs.

[0017] It is desirable that the analysis device further includes a setting unit that sets the section in the measurement data where the over-torque occurs. The analysis device may also include a user interface that allows an operator to specify the section in the measurement data where the over-torque occurs. This makes it possible to appropriately set the over-torque section.

[0018] The interface is preferably a transmitter that wirelessly transmits the measurement data to the analysis device. By using a wireless transmitter, wiring between the measurement device and the analysis device is not required, making it possible to easily measure at any measurement location. The interface may also be a wired interface that transmits the measurement data to the analysis device. [Effects of the Invention]

[0025] The present invention makes it possible to provide a concrete compressive strength measuring method and the like that can measure the compressive strength of hardened concrete simply and with high accuracy. [Brief explanation of the drawings]

[0026] [Figure 1] A diagram showing the overall configuration of the concrete compressive strength measurement system 1. [Figure 2] (a) Side view of the measuring device 3, (b) Front view, (c) AA′ cross section [Figure 3] Block diagram showing the functional configuration of the measurement device 3 and the computer (analysis device 5) [Figure 4] Graph showing the time variation of torque reaction force obtained based on measurement data [Figure 5] Flowchart showing the overall flow of the concrete compressive strength measurement method [Figure 6] 6 is a flowchart showing the procedure of the estimation process in step S104 of FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0028] Fig. 1 is a diagram showing the overall configuration of a concrete compressive strength measurement system 1 according to the present invention. As shown in Fig. 1, the concrete compressive strength measurement system 1 is configured to include a measurement device 3 attached to a drill 21 of an electric screwdriver 2, and an analysis device 5 (computer) that analyzes the compressive strength of a hardened concrete member 10 (hereinafter referred to as concrete member 10) based on data measured by the measurement device 3.

[0029] The electric screwdriver 2 is a driver for screwing male threads 4 (screws, bolts) into a concrete member 10, and is a typical electric screwdriver equipped with a driver bit 22, a drill 21, a motor for rotating the drill 21, a power supply unit for supplying power to the motor, a power ON / OFF switch, etc. In the measurement method of the present invention, the electric screwdriver 2 has a rotation speed adjustment function for maintaining the rotation speed of the electric screwdriver 2 constant.

[0030] A measuring device 3 is attached to the drill 21 of the electric screwdriver 2. FIG. 2 shows the configuration of the measuring device 3, with (a) being a side view, (b) being a front view, and (c) being a cross-sectional view taken along the line AA′ in FIG. 2(a). As shown in FIG. 2, the measuring device 3 includes a measuring unit 31 fixedly attached to the drill 21 of the electric screwdriver 2, a main body 30 including an interface 32 and a power supply 34, and a fixing unit 33 that fixes the measuring unit 31 to the main body 30. As shown in FIG. 2, the measuring unit 31 is a strain gauge attached to the surface of an extension bar 35 that is fitted to the drill 21. The extension bar 35 is made of a rigid member and has a fitting portion for fitting the drill 21 at one end and a fitting portion for fitting the driver bit 22 at the other end. The extension bar 35 is attached to the drill 21 by passing through a hole provided in the center of the main body 30. Note that the attachment method, shape, size, and dimensions of each part are merely examples and are not limited to those shown in the figures.

[0031] The measuring unit 31 (strain gauge) is a component that measures data for determining the torque reaction force that occurs in the concrete member 10 when the male screw 4 is being screwed into the concrete member 10. When the male screw 4 is screwed into the concrete member 10 using the electric screwdriver 2, a torque reaction force is generated in the concrete member 10, and this force is transmitted to the extension bar 35 via the male screw 4 and the driver bit 22, causing rotational strain. The measuring unit 31 measures the amount of rotational strain transmitted to the extension bar 35 as measurement data. The measuring unit 31 outputs the measurement data (strain amount data) measured by the strain gauge to the analysis device 5 via the interface 32.

[0032] For example, as shown in Figure 2, if a strain gauge (measuring unit 31) is attached to the surface of extension bar 35 attached to drill 21 at a 45-degree angle to the drill rotation axis, the strain on the axis surface will be proportional to the torque applied to the axis. Therefore, by measuring the amount of strain on the surface, the torque reaction force of concrete member 10 can be determined. Below is an example of an equation that expresses the relationship between rotational strain and torque reaction force.

[0033] T=k δ δ=ε L where: T: Torque [N / mm] k: instrument constant (constant specific to the measuring device) [N] δ: Torsional displacement [mm] ε: Torsional strain [dimensionless] (value measured with a strain gauge) L: Length of the measurement point (length of the strain gauge) [mm]

[0034] The number and positions of the strain gauges attached to the extension bar 35 are optional. The wires of the strain gauges are connected to the interface 32, and measurement data is output to the interface 32 in sequence.

[0035] The interface 32 is a communication interface that outputs the measurement data measured by the measuring unit 31 to the analyzing device 5, and can be, for example, a wireless transmitter such as Bluetooth (registered trademark). By using a wireless transmitter, the measuring device 3 can be easily attached to the electric screwdriver 2, making it suitable for measurements in a variety of locations. The interface 32 is housed inside the main body 30 (e.g., the upper case 30a) and electrically connected to the measuring unit 31 and the power supply unit 34. The internal space of the upper case 30a is filled with a filler 36 made of a resin such as GFRP (Glass Fiber Reinforced Plastic). Power is supplied to the interface 32 from the power supply unit 34. The interface 32 may also be a wired interface that outputs the measurement data to the analyzing device 5 via a cable.

[0036] The power supply unit 34 includes a battery (lithium ion battery) and wiring that supply power to the interface 32, and is housed, for example, in the lower case 30b of the main body 30. The space in the lower case 30b other than the space occupied by the power supply unit 34 may be filled with a resin material or the like, or may be hollow. It is also desirable that the lower case 30b be provided with an opening and a lid for inserting and removing the battery.

[0037] The fixing part 33 is a member for fixing the main body part 30 of the measuring device 3 and the measuring part 31 (extension bar 35) attached to the drill 21 of the electric screwdriver 2.

[0038] Next, the analysis device 5 will be described. As shown in FIG. 3, the analysis device 5 is configured by a computer in which a control unit 51, a memory unit 52, a communication unit 53, an input unit 54, a display unit 55, a peripheral device I / F (interface) unit 56, etc. are connected via a bus, and a PC, tablet, smartphone, etc. can be used. The configuration of the analysis device 5 can be changed as appropriate. The analysis device 5 acquires measurement data measured by the measuring device 3 attached to the electric screwdriver 2 via the communication unit 53 or the peripheral device I / F unit 56 of the analysis device 5. The analysis device 5 estimates the compressive strength of the concrete member 10 based on the acquired measurement data. A method for estimating compressive strength will be described later.

[0039] The control unit 51 is composed of a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. The CPU loads programs stored in the memory unit 52, ROM, etc. into a work memory area on the RAM and executes them, driving and controlling each unit (memory unit 52, communication unit 53, input unit 54, display unit 55, peripheral device I / F unit 56) connected via a bus. The ROM permanently stores programs such as a boot program and BIOS, data, etc. The RAM temporarily stores loaded programs and data and also provides a work area used by the control unit 51 to perform various processes.

[0040] The storage unit 52 is a storage device such as a flash memory or a hard disk, and stores the acquired measurement data, the estimated results of the compressive strength, etc. The storage unit 52 also stores a program related to the compressive strength estimation process.

[0041] The communication unit 53 is an interface that has a communication port for a wireless communication unit such as a WiFi antenna, Bluetooth, or a wired communication unit such as a LAN, and a communication control device, and mediates communication with external devices. Note that the communication unit 53 must be equipped with a communication interface that corresponds to the interface 32 of the measurement device 3 and can receive measurement data measured by the measurement device 3.

[0042] The input unit 54 includes, for example, a touch panel, a keyboard, a pointing device such as a mouse, an input device such as a numeric keypad, and the like, and inputs input data to the control unit 51.

[0043] The display unit 55 is composed of a display such as a liquid crystal panel and a logic circuit (such as a video adapter) for executing display processing in cooperation with the display, and causes the display to display display data input under the control of the control unit 51. The display unit 55 may be a touch panel display in which an input device (input unit 54) such as a touch panel is integrally provided on the display screen.

[0044] The peripheral device I / F unit 56 is a port for connecting peripheral devices, and the control unit 51 transmits and receives data to and from the peripheral devices via the peripheral device I / F unit 56. The peripheral device I / F unit 56 is configured by a USB (Universal Serial Bus) or the like. The connection with the peripheral devices may be wired or wireless.

[0045] Next, the functional configuration of the analysis device 5 will be described. The analysis device 5 has a measurement data acquisition unit 511, a compressive strength estimation unit 513, a result output unit 515, etc. These functional units are realized by the CPU of the control unit 51 reading a program related to the compressive strength estimation process stored in the storage unit 52, calling it into a work memory area on the RAM, and executing it.

[0046] The measurement data acquisition unit 511 acquires the measurement data output from the measuring device 3 via the communication unit 53 or the peripheral device I / F unit 56. Alternatively, the communication unit 53 may acquire the measurement data stored in the memory unit 52, the measurement data saved on another computer, or the measurement data saved on the cloud via a network such as a LAN or the Internet, and import the data into the control unit 51. The measurement data is data on the amount of rotational strain generated in the drill 21 of the electric screwdriver 2 when the electric screwdriver 2 is screwing the male screw 4 into the concrete member 10.

[0047] The compressive strength estimation unit 513 estimates the compressive strength of the concrete member 10 based on the measurement data acquired by the measurement data acquisition unit 511. Specifically, the compressive strength estimation unit 513 estimates the compressive strength of the concrete member 10 based on the measurement data (strain amount data) during the period when, after the screw head of the male screw 4 contacts the concrete member 10 and is further screwed in to generate an over-torque (over-torque section). The compressive strength estimation unit 513 obtains the torque reaction force generated in the concrete member 10 from the measurement data (strain amount data), calculates the time integral value of the torque reaction force in the over-torque section, and estimates the compressive strength of the concrete member 10 based on the calculated time integral value.

[0048] Figure 4 is a graph showing the time change of the torque reaction force when the male screw 4 is screwed into the concrete member 10 using the electric driver 2. During the measurement, the rotation speed of the electric driver 2 is kept constant. The horizontal axis of the graph is the time t, and the vertical axis indicates the magnitude of the torque reaction force [N·m]. In the graph of Figure 4, the section of t0 < t ≤ ta is the state where the tip of the male screw 4 starts to enter the concrete member 10. The section of ta < t ≤ tb is the state where the male screw 4 is screwing into the concrete member 10 with a substantially constant torque. The section of tb < t ≤ tc is the state where the screw head of the male screw 4 contacts the surface of the concrete member 10 and is further screwed in. That is, it is the state where an over-torque has occurred. The section of tc < t ≤ td is the state where the thread is broken due to the over-torque and it rotates freely.

[0049] The compressive strength estimation unit 513 calculates the torque reaction force of the concrete member 10 in the over-torque section of tb < t ≤ tc from the strain amount data transmitted to the drill 21 (extension bar 35), and calculates the time integral value of the torque reaction force in the over-torque section. There is a positive correlation between the time integral value of the torque reaction force in the over-torque section and the concrete compressive strength. The compressive strength estimation unit 513 calculates the time integral value of the torque reaction force in the over-torque section, and estimates the compressive strength of the concrete member 10 based on the correlation between the time integral value of the torque reaction force and the concrete compressive strength.

[0050] Note that the over-torque section may be set by the control unit 51 analyzing the measurement data, or may be specified by the operator. When the control unit 51 sets the over-torque section, the control unit 51 obtains, for example, a reference value (e.g., an average value) of the torque reaction force from the section of the graph where ta < t ≤ tb (the section where the male screw 4 is advancing with a substantially constant torque), and sets the section from when the value on the graph starts to exceed the reference value by a predetermined value until it falls below the predetermined value of the reference value as the over-torque section.

[0051] When the operator sets the over-torque section, the control unit 51 provides a user interface (over-torque section setting screen) for specifying the over-torque section. The control unit 51 causes the display unit 55 to display the measurement data or a graph of the torque reaction force calculated from the measurement data (FIG. 4), and accepts setting operations for the time point tb when the screw head of the male screw 4 starts to contact the surface of the concrete member 10 and over-torque starts to occur, and the time point tc when the thread is broken and freewheeling on the graph.

[0052] The result output unit 515 outputs the estimation result of the compressive strength estimated by the compressive strength estimation unit 513. The output methods include display on the display unit 55, storage in the storage unit 52, transmission to an external device via the communication unit 53, or output to the outside via the peripheral device I / F unit 56 (e.g., print output by a printer).

[0053] Next, a concrete compressive strength measurement method using the concrete compressive strength measurement system 1 will be described. First, referring to the flowchart of FIG. 5, the overall flow of the measurement will be described.

[0054] The operator screws the male screw 4 into the concrete member 10 to be measured using the electric driver 2 attached with the measuring device 3 (step S101). The drill rotation speed of the electric driver 2 is adjusted to maintain a constant speed.

[0055] The measuring unit 31 of the measuring device 3 measures the rotational strain that occurs in the drill 21 when the electric screwdriver 2 is screwing in the male screw 4 (step S102). The rotational strain is output sequentially as measurement data to the analysis device 5 via the interface 32 (step S103). The measurement of the rotational strain continues until the tip of the male screw 4 begins to enter the concrete member 10, is screwed into the concrete member 10, the screw head comes into contact with the surface of the concrete member 10, and continues to be screwed in until over-torque occurs, the thread breaks, and the screw starts to spin freely.

[0056] The analysis device 5 (computer) sequentially acquires the measurement data output from the measurement device 3 and stores it in the RAM or memory unit 52. The analysis device 5 estimates the compressive strength of the concrete member 10 based on the series of measurement data (step S104).

[0057] FIG. 6 is a flowchart illustrating the processing steps of the analysis device 5 (computer) in the compressive strength estimation processing in step S104 of FIG.

[0058] The control unit 51 (measurement data acquisition unit 511) of the analysis device 5 acquires measurement data from the measurement device 3 (step S201). The control unit 51 sets an over torque section in the measurement data (step S202). Alternatively, the control unit 51 displays a user interface (over torque section setting screen) to accept the setting of the over torque section by the operator.

[0059] The control unit 51 (compressive strength estimation unit 513) obtains the torque reaction force from the measurement data (strain amount data) based on a predetermined relational expression, calculates the time integral value of the torque reaction force in the set over-torque section (step S203), and estimates the compressive strength of the concrete member 10 based on the calculated time integral value (step S204).

[0060] The control unit 51 (result output unit 515) outputs (displays, stores, transmits data, prints out, etc.) the estimation result of the compressive strength of the concrete member 10 estimated by the compressive strength estimation unit 513 (step S205).

[0061] As described above, by using the concrete compressive strength measurement system 1 according to the present invention, it is possible to estimate the compressive strength of concrete through the simple task of screwing a male screw 4 into a concrete member 10 with an electric screwdriver 2. This allows measurements to be performed directly on the target concrete structure, eliminating the need for prior core sampling or pre-measurements using a test specimen, as in conventional methods. Furthermore, damage to the measurement site is limited to the drilled hole for the screw, making repairs easy. Furthermore, estimating the compressive strength does not require many parameters; instead, it is sufficient to measure the amount of rotational strain generated in the drill 21. Furthermore, the compressive strength of concrete is estimated based on the relationship between the torque reaction force generated in the concrete member 10 in the over-torque region (the state in which the screw head makes contact and then attempts to further drive it in) and the compressive strength of the concrete, resulting in highly accurate estimation results.

[0062] Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. For example, the shape, size, and mounting method of the measuring device 3 are merely examples, and other shapes, sizes, and mounting methods may be adopted. It is clear that a person skilled in the art can conceive of various modified or altered examples within the scope of the technical ideas disclosed in this application, and it is understood that these also naturally fall within the technical scope of the present invention. [Explanation of symbols]

[0063] 1. Concrete compressive strength measurement system 2. Electric screwdriver 3. Measuring equipment 4... Male thread 5. Analysis device (computer) 10. Concrete members 21 Drill 22 Driver bit 30 Main body 31...Measurement section 32...Interface 33... Fixed part 34...Power supply section 35 Extension bar 36. Filler 51 Control unit 52...Storage section 53 Communications Department 54 Input section 55...Display section 56 Peripheral device I / F section 511 Measurement data acquisition unit 513···Compressive strength estimation section 515...Result output section

Claims

1. a step of screwing a male screw into a concrete member using an electric screwdriver having a function of maintaining a constant rotation speed; a step of measuring measurement data for determining a torque reaction force generated when the male screw is being screwed in by a measuring device; an estimation step in which the torque reaction force is calculated based on measurement data obtained while the head of the male screw is in contact with the concrete member and over-torque is occurring, and an analysis device estimates the compressive strength of the concrete member; A method for measuring the compressive strength of concrete, including:

2. 2. The method for measuring compressive strength of concrete according to claim 1, wherein in the estimation step, a time integral value of the torque reaction force while the over-torque is occurring is calculated, and the compressive strength of the concrete member is estimated based on the calculated time integral value.

3. 3. The method for measuring compressive strength of concrete according to claim 1, wherein the measurement data is data on the amount of rotational strain transmitted from the concrete member to the electric screwdriver.

4. 4. The method for measuring compressive strength of concrete according to claim 1, further comprising a step in which the analysis device sets a section in the measurement data where the over-torque occurs.

5. 4. The method for measuring compressive strength of concrete according to claim 1, further comprising a step in which an operator specifies a section in the measurement data where the over-torque occurs.

6. A concrete compressive strength measurement system including a measurement device and an analysis device, The measuring device is a measurement unit that measures measurement data for determining a torque reaction force that occurs when a male screw is screwed into a concrete member using an electric screwdriver that has a function of maintaining a constant rotation speed; an interface that outputs the measurement data to the analysis device; a fixing portion that fixes the measurement portion and the interface to the drill of the electric screwdriver, The analysis device a measurement data acquisition unit that acquires measurement data measured by the measurement device; an estimation unit that calculates the torque reaction force based on measurement data from the measurement data obtained while the screw head of the male screw is in contact with the concrete member and over-torque is occurring, and estimates the compressive strength of the concrete member using the analysis device; A concrete compressive strength measurement system comprising:

7. The concrete compressive strength measurement system according to claim 6, characterized in that the estimation unit calculates a time integral value of the torque reaction force while the over-torque is occurring, and estimates the compressive strength of the concrete member based on the calculated time integral value.

8. 8. The method for measuring compressive strength of concrete according to claim 6, wherein the measurement data is data on the amount of rotational strain transmitted from the concrete member to the electric screwdriver.

9. The analysis device 9. The concrete compressive strength measurement system according to claim 6, further comprising a setting unit that sets a section in the measurement data where the over-torque occurs.

10. The analysis device 9. The concrete compressive strength measurement system according to claim 6, further comprising a user interface for an operator to specify the section in the measurement data where the over-torque occurs.

11. 11. The concrete compressive strength measurement system according to claim 6, wherein the interface is a transmitter that wirelessly transmits the measurement data to the analysis device.

12. 11. The concrete compressive strength measurement system according to claim 6, wherein the interface is a wired interface that transmits the measurement data to the analysis device.

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