JP2008128831A - Method and system for estimating concrete strength, and drilling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To readily estimate the concrete strength of a concrete structure, with high accuracy. <P>SOLUTION: In this estimation method of concrete strength for estimating the concrete strength of an existing concrete structure, the cutting speed of a grindstone bit 55 is measured, while the concrete structure 65 is cut by a definite thrust using the grindstone bit 55 and the concrete strength of the concrete structure 65 is estimated on the basis of the measured value. In this case, a plurality of concrete structures 65 that differ in concrete strength are preliminarily manufactured, and each of the concrete structures is cut by the grindstone bit 55, while the thrust for preliminarily calculating the relation between the pressing force of the grindstone bit 55 to each of the concrete structures and a cutting speed is cut; and on the basis of the relation between the preliminarily calculated pressing force and the cutting speed, the concrete structure of the existing concrete structure 65 is estimated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a concrete strength estimation method, a concrete strength estimation system, and a drilling device for estimating the concrete strength of an existing concrete structure.

  In general, there are various methods for measuring the concrete strength of an existing concrete structure, such as a method for measuring a compressive strength using a compressive strength tester, a method for measuring a compressive strength by a rebound hardness method, and the like. An appropriate measurement method according to the object is used.

The method of measuring using a compressive strength tester is a method specified in JIS (JIS A1107, JIS A1108), in which a core specimen is taken from a concrete structure, and the core specimen is taken into a test room. In this method, the compressive strength of a concrete structure can be obtained by performing a compressive strength test with a compressive strength tester. The rebound hardness method is a highly versatile method that can estimate the compressive strength from the rebound hardness by striking the surface of a concrete structure with a test hammer, and can be measured in the field nondestructively.
JIS A 1107, Core sampling method and compressive strength test method JIS A 1108, compressive strength test method for concrete

  However, in the method using the compressive strength tester, the work of collecting the core test specimen from the concrete structure, the work of carrying the core test specimen into the test room and setting it in the compressive strength tester, etc. Time and effort. In addition, the method based on the rebound hardness method can only determine the strength of the surface of the concrete structure, so the compressive strength of the concrete structure cannot be determined with high accuracy.

  The present invention has been made in view of the above-described conventional problems, and a concrete strength estimation method and a concrete strength estimation method capable of easily obtaining a concrete strength of an existing concrete structure with high accuracy. It is an object to provide a system and a drilling device.

The present invention employs the following means in order to solve the above problems.
That is, the invention according to claim 1 is a concrete strength estimation method for estimating the concrete strength of an existing concrete structure, and the grinding stone bit is cut while the concrete structure is cut with a constant driving force by the grinding stone bit. The cutting speed is measured, and the concrete strength of the concrete structure is estimated based on the measured value.

  According to the method for estimating concrete strength according to the present invention, the concrete strength of the concrete structure can be estimated by cutting the concrete structure with the grindstone bit and measuring the cutting speed of the grindstone bit at that time. Therefore, the concrete strength of the concrete structure can be estimated easily and with high accuracy.

  The invention according to claim 2 is the concrete strength estimation method according to claim 1, wherein a plurality of concrete structures having different concrete strengths are manufactured in advance, and the propulsive force of each concrete structure is changed by a grindstone bit. By cutting, the relationship between the pressing force of the grindstone bit on each concrete structure and the cutting speed is obtained, and the concrete strength of the existing concrete structure is determined based on the relationship between the obtained pressing force and the cutting speed. It is characterized by estimating.

  According to the method for estimating concrete strength according to the present invention, when the concrete structure to be estimated is cut according to the relationship between the pressing force and the cutting speed inherent to a plurality of concrete structures having different concrete strengths obtained in advance. By applying the obtained cutting speed, the concrete strength corresponding to the cutting speed can be obtained, and the concrete strength of the estimation target concrete structure can be estimated.

  The invention according to claim 3 is the method for estimating concrete strength according to claim 1 or 2, wherein when the concrete structure is cut with a grindstone bit, a cylindrical grindstone having a flat perforated surface is formed. A drilling device including a bit, a driving unit that rotationally drives the grindstone bit, a propulsion unit that propels the grindstone bit, and a control unit that controls the driving unit and the propulsion unit is used.

  According to the concrete strength estimating method of the present invention, a concrete structure is obtained by using a drilling device and propelling it with a constant propulsive force while rotating the grindstone bit in cooperation with the driving unit and the propelling unit of the drilling device. A predetermined hole is formed in the surface. And, when drilling the concrete structure, by measuring the cutting speed of the grinding wheel bit, the concrete strength corresponding to the cutting speed can be obtained, and the concrete strength of the estimation target concrete structure can be estimated. it can.

  The invention according to claim 4 is a concrete strength estimation system for estimating the concrete strength of an existing concrete structure, and a cylindrical grindstone bit having a flat perforated surface and a rotational drive of the grindstone bit. A drilling device comprising a drive means, a propulsion means for propelling the grindstone bit, and a control means for controlling the drive means and the propulsion means is used, and the control means has a plurality of different concrete strengths determined in advance. Storing the relationship between the pressing force of the grindstone bit on the concrete structure and the cutting speed as information, and estimating the concrete strength of the existing concrete structure based on the stored information. Features.

  According to the concrete strength estimating system according to the present invention, when the hole is formed in the concrete structure by the grindstone bit of the drilling device, the information stored in the control means (the above-described information on the plurality of concrete structures having different concrete strengths). Based on the relationship between the pressing force of the grindstone bit and the cutting speed, the concrete strength of the estimation target concrete structure can be estimated.

  The invention according to claim 5 is a cylindrical grindstone bit having a flat perforated surface, driving means for rotating the grindstone bit, propulsion means for propelling the grindstone bit, the driving means and the propulsion. Control means for controlling the means, and the control means stores, as information, a relationship between the pressing force of the grindstone bit and the cutting speed with respect to a plurality of concrete structures having different concrete strengths obtained in advance. It is comprised so that the concrete strength of the said existing concrete structure may be estimated based on information.

  According to the drilling device of the present invention, the predetermined hole is formed in the concrete structure by propelling the grindstone bit of the drilling device while rotating it in cooperation with the driving means and the propelling means. And based on the information (the relationship between the pressing force of the grinding stone bit and the cutting speed for a plurality of concrete structures having different concrete strengths) stored in advance in the control means during the drilling operation for the concrete structure, The concrete strength of the estimation target concrete structure can be estimated.

As described above, according to the concrete strength estimation method drilling method, concrete strength estimation system, and drilling device of the present invention, by measuring the cutting speed while cutting a concrete structure with a grindstone bit, The concrete strength of the concrete structure can be estimated from the measured value. Therefore, the work of collecting the core specimen from the concrete structure, the work of performing the compressive strength test by applying the core specimen to the compressive strength tester, etc. are not required, so the concrete strength of the estimation target concrete structure can be easily estimated. be able to.
In addition, since the concrete strength of the concrete structure is estimated by cutting the concrete structure, there is no need to measure only the surface of the concrete structure unlike the rebound hardness method, and the concrete strength is highly accurate. Can be estimated.
Furthermore, since a concrete structure may be cut by a drilling device, it can be applied to estimate the concrete strength of various concrete structures, and versatility can be improved.

Hereinafter, embodiments of the present invention shown in the drawings will be described.
1 to 6 show an embodiment of the present invention, which is effective in estimating the concrete strength of various existing concrete structures, The apparatus is configured to obtain the concrete strength of the concrete structure by drilling the concrete structure with a drilling device.

  That is, as shown in FIG. 1, the drilling device 1 used in the present embodiment includes a grindstone bit 55, a driving means 30 that rotationally drives the grindstone bit 55, a propulsion means 15 that propels the grindstone bit 55, and a grindstone Fluid supply means 45 for supplying fluid (liquid such as polishing water, gas such as air, or a mixture of liquid and gas, etc., and polishing water is used in the present embodiment) to the bit 55, and driving The frame 2 that supports the means 30 and the propulsion means 15 and the control means 50 that controls the drive means 30 and the propulsion means 15 are provided.

  As shown in FIGS. 1 to 3, the frame 2 includes a base 3 that is fixed to the upper portion of the concrete structure 65 by vacuum suction, and a support shaft 13 that is provided vertically on the upper portion of the base 3. The frame 2 supports the propulsion means 15 and the drive means 30.

  The base 3 has a plate shape, and as shown in FIGS. 2 and 3, a plurality of recesses 4 communicating with each other through the communication holes 5 are provided on the lower surface side. One of the four is provided with a connection port 6 that penetrates the inside and outside of the recess 4, and a vacuum pump (not shown) is connected to the connection port 6 via a pipe.

  An annular packing 8 is integrally provided at the opening peripheral edge of each recess 4 of the base 3 so as to surround each recess 4, and when the base 3 is positioned above the concrete structure 65, these The space between the base 3 and the concrete structure 65 is sealed by the packing 8, and sealed spaces 7 are formed in portions corresponding to the respective recesses 4 of the base 3. Then, the inside of the void 7 is vacuum-sucked by a vacuum pump, whereby the base 3 is vacuum-adsorbed on the upper part of the concrete structure 65, and the entire punching device 1 is fixed on the upper part of the concrete structure 65.

  As shown in FIGS. 1 and 2, a through hole 9 that penetrates the base 3 in the vertical direction is provided in the center portion of the base 3, and a grindstone holder 34 and a grindstone holder 34 to be described later in the through hole 9. The grindstone bit 55 attached to the knives is configured to be able to be inserted from above and below.

  As shown in FIG. 1, an annular guide 10 is fitted into the upper end opening of the through hole 9, and the grindstone holder 34 is guided by the guide 10 so as to be movable in the vertical direction, and is attached to the grindstone holder 34. The bit 55 is prevented from causing rotational runout.

  As shown in FIG. 1, an annular bush 11 is fitted in the lower end opening of the through hole 9, and the polishing water supplied to the grindstone bit 55 and the concrete structure 65 are drilled by the bush 11. Is prevented from leaking around the perforating apparatus 1 through the space between the base 3 and the concrete structure 65.

  As shown in FIG. 1, the base 3 is provided with an escape hole 12 having one end opened on the inner peripheral side of the through hole 9 and the other end opened on the outer peripheral side of the base 2. 12 is a drainage channel 47, and the grinding water supplied to the grindstone bit 55 from the fluid supply unit 45 through the drainage channel 47 and the cutting margin generated during the drilling operation of the concrete structure 65 are the fluid supply unit. Return to 45.

  As shown in FIG. 1, the propulsion means 15 is provided inside the support shaft 13, a plate-shaped moving table 16 provided so as to be movable in the vertical direction along the outer surface of the support shaft 13, and the moving table 16. The actuator 20 is configured to advance and retract in the vertical direction, and a pressure supply source 21 that drives the actuator 20.

  The actuator 20 is a pneumatic cylinder or a hydraulic cylinder having a linearly movable rod. By supplying air pressure or hydraulic pressure from the pressure supply source 21 to the actuator 20 via the pipe 22 and the switching valve 23, the rod is directly moved. It is configured to move.

  In the present embodiment, a pneumatic cylinder is used as the actuator 20, a compressor is used as the pressure supply source 21, and the pneumatic cylinder is provided inside the support shaft 13 so that the rod can move in the vertical direction. The moving table 16 is integrally connected to the rod of the pneumatic cylinder.

  A driving unit 30 is attached to the moving table 16 of the propulsion unit 15 via an attachment jig 17, and the driving unit 16 follows the moving table 16 by moving the moving table 16 up and down by operating the actuator 20. 30 moves forward and backward.

  By driving the actuator 20 and moving the driving means 30 up and down in the vertical direction, a propulsive force corresponding to the pressure from the pressure supply source 21 is applied to the grindstone bit 55 attached to the driving means 30. The actuator 20 may be configured to move the moving table 16 in the vertical direction by using an electric, pneumatic, or hydraulic rotating machine and converting the rotation of the rotating machine into a linear motion by a conversion mechanism. Good.

  The moving table 16 is provided with a displacement detecting means 25, and the displacement detecting means 25 moves the moving table 16 in the vertical direction, that is, the vertical displacement of the grindstone bit 55 attached to the moving table 16 via the driving means 30. Is detected. In the present embodiment, a laser displacement meter 26 is attached to the support shaft 13, a reflecting mirror 27 is attached to the part of the moving table 16 facing the laser displacement meter 26, and the displacement detection means 25 is configured by a combination thereof. . However, the present invention is not limited to these combinations as long as the vertical displacement of the grindstone bit 55 can be detected.

  As shown in FIG. 1, the driving means 30 is attached to a moving table 16 of the propelling means 15 via a mounting jig 17, and a driving motor 31 that can move up and down integrally with the moving table 16, and a driving motor The chuck 33 is detachably attached to the drive shaft 32 of the 31, and the grindstone holder 34 is detachably attached to the chuck 33, and the grindstone bit 55 is detachably attached to the grindstone holder 34. Note that a pneumatic or hydraulic rotating machine may be used instead of the drive motor 31.

  As shown in FIG. 4, the grindstone holder 34 includes a round bar-shaped mounting shaft 35 and a cylindrical holder body 40 that is integrally connected to the tip of the mounting shaft 35. The mounting shaft 35 is placed in the chuck 33. The grindstone holder 34 is attached to the chuck 33 by inserting and tightening the chuck 33.

  A communication hole 36 having one end opened on the peripheral surface and the other end opened on the lower end surface is provided inside the attachment shaft 35, and the lower end opening of the communication hole 36 communicates with the inside of the holder body 40. . A cylindrical joint 37 whose upper and lower ends are closed is integrally attached to the outer peripheral surface of the attachment shaft 35 so that the attachment shaft 35 penetrates through the center thereof, and the attachment shaft 35 communicates with the inside of the joint 37. One end opening of the hole 36 communicates.

  A part of the peripheral surface of the joint 37 is provided with an inflow hole 38 penetrating inside and outside. The inflow hole 38, the inside of the joint 37, the communication hole 36 of the mounting shaft 35, the inside of the holder main body 40, A series of supply passages 39 is constituted by the lower end opening of the holder body 40, and polishing water is supplied from the fluid supply means 45 to the grindstone bit 55 through the supply passages 39.

  The inner peripheral surface of the lower end opening of the holder body 40 is formed in a mounting portion 41 having a larger diameter than other portions, and a mounting portion 58 of a grindstone bit 55 described later is attached to the mounting portion 41. The grindstone holder 34 is configured so that the holder main body 40 can be inserted through the through hole 9 of the base 3 of the frame 2, and can be moved in the vertical direction by a guide 10 provided at the upper end opening of the through hole 9. Has been.

  As shown in FIG. 1, the fluid supply means 45 supplies a polishing tank 46 for storing polishing water, supplies polishing water from the storage tank 46 to the grinding stone bit 55 via the supply path 39, and supplies the grinding stone bit 55 to the grinding stone 55. A pump 48 for returning the supplied polishing water to the storage tank 46 via the drainage channel 47 and a valve (not shown) for adjusting the amount of polishing water supplied from the storage tank 45 are provided. A filter (not shown) for filtering the polishing water returned from the bit 55 is provided. There is no restriction | limiting in particular as polishing water, A gel-like liquid, a foam-like liquid, etc. can be used.

  As shown in FIGS. 5 and 6, the grindstone bit 55 includes a cylindrical grindstone main body 56 with a perforated surface 37 formed in a flat surface, and a cylindrical mounting portion 58 provided integrally with one end of the grindstone main body 56. As shown in FIG. 4, the grindstone bit 55 is integrally attached to the holder body 40 by fitting or screwing the attachment portion 58 to the attachment portion 41 of the holder body 40.

  The grindstone main body 56 is obtained by sintering abrasive grains with a binder, and various known grindstones can be used. The grindstone main body 56 is provided with a core hole 59 penetrating in the axial direction at a position eccentric from the central axis. When the grindstone bit 55 is attached to the grindstone holder 34, the core hole 59 is formed in the mounting portion 58. It communicates with the supply path 39 of the grindstone holder 34 via the peripheral side. A type in which the core hole 59 is located on the central axis may be used.

  The grindstone main body 56 is provided with at least one hole 60 penetrating the inside and outside of the grindstone main body 56, and polishing water and cutting water circulate between the inside and outside of the core hole 59 of the grindstone bit 55 through the hole 60. Polishing water and cutting water are sealed in the core hole 59 of the grindstone bit 55 to prevent the frictional heat between the grindstone bit 55 and the concrete structure 65 from increasing.

  As shown in FIG. 7, at least one slit 61 that penetrates the inside and outside of the core hole 59 is provided in the drilled surface 57 of the grindstone main body 56 of the grindstone bit 55, and polishing water and cutting water are cut through the slit 61. The filter may be circulated between the inside and outside of the core hole 59.

  As shown in FIG. 1, the control means 50 is configured to control the power supply 29 of the pressure supply source 21 of the propulsion means 15 and the drive motor 31 of the drive means 30. Further, the control means 50 obtains information on the drilling work for the concrete structure 65 of the grindstone bit 55 previously obtained (relationship between the drilling depth and the drilling time at a constant driving force (pressing force) (see FIG. 8). ) Is stored, and based on this information, the drive motor 31 and the pressure supply source 21 of the grindstone bit 55 are controlled to stop after a lapse of a certain time from the start of drilling.

  Then, the perforating apparatus 1 configured as described above is positioned at a predetermined position above the concrete structure 65, and the vacuum pump is operated to cause the base 3 of the frame 2 to be vacuum-adsorbed onto the top of the concrete structure 65. The drilling device 1 is fixed to the upper part of the concrete structure 65.

  Then, the power supply 29 is turned on, the drive motor 31 is operated, the grindstone bit 55 is rotated via the grindstone holder 34, the pump 48 of the fluid supply means 45 is actuated, and the storage tank 46 and the core hole of the grindstone bit 55 are operated. The polishing water is circulated between the motor 59, the actuator 20 is operated, and the grindstone bit 55 is propelled downward at a constant propulsion speed via the movable table 16, the drive motor 31, and the grindstone holder 34, thereby providing concrete. The structure 65 is drilled downward by the grindstone bit 55, and a hole 70 having a predetermined diameter and depth is formed in the concrete structure 65.

  Here, FIG. 8 shows the relationship between the cutting time and the cutting depth when the propulsive force (pushing force) of the grindstone bit 55 obtained by drilling the concrete structure 65 with the drilling device 1 is constant. . In FIG. 8, (a) shows a pushing force of 45.5 N, (b) shows a pushing force of 53.8 N, (c) shows a pushing force of 61.5 N, and (d) shows a pushing force of 76.9 N. The horizontal axis represents the cutting time, and the vertical axis represents the cutting depth.

  From this experimental result, when the grindstone bit 55 comes into contact with the concrete structure 65 and cutting is started, the cutting depth increases with the cutting time, and the cutting depth changes while taking a gentle curve. It can be seen that a linear locus indicating the relationship is taken. The change in the trajectory is considered to be the influence of various aggregates inside the concrete structure 65.

  Further, the cutting depth increases with time, but becomes constant with a certain point (inflection point) as a boundary. That is, it will be in the state which is not cut. When the pushing force is 61.5 N or less, this state continues even if time elapses. This indicates that the grindstone bit 55 comes into contact with the embedded object (CD tube) and the frictional resistance is reduced, so that the sliding state is caused, and as a result, further cutting is impossible. On the other hand, when the pressing force is 76.9 N, the cutting depth takes a constant value at the inflection point, but it turns out to change in a pulse shape when a certain time comes. This shows that the surface of the buried object (CD pipe) was cut because the sliding force occurred at the inflection point but the pushing force was large, and finally the buried object (CD pipe) was penetrated.

Next, FIG. 9 shows the relationship between the pressing force (propulsion force) and the cutting speed (propulsion speed) obtained from the experimental results of FIG.
From this result, the cutting speed takes a value almost proportional to the pressing force, and the higher the concrete strength, the smaller the gradient, and the pressing force that does not penetrate the embedded object (CD pipe) is related to the concrete strength. It can be seen that it is approximately 60N. In other words, this value is expected to depend on the material strength of the buried object (CD tube), so by checking the strength in advance, obtain the pressing force that cannot be cut for each buried object (CD tube). Can do.

Next, by rewriting based on the result of FIG. 9, the relationship between the cutting speed and the concrete strength is obtained as shown in FIG.
For each pressing force, a straight line with a negative gradient is obtained. As a result, the concrete structure 65 is cut if the pressing force is known and the cutting speed is known by cutting the concrete structure 65 by the above-described perforating apparatus 1. A concrete strength of 65 can be estimated.

  In the concrete strength estimation method, the concrete strength estimation system, and the drilling apparatus 1 configured as described above, when the concrete structure 65 is cut by the grindstone bit 55 and the hole 70 is formed. In addition, the cutting speed by the grindstone bit 55 is measured, and the concrete strength can be estimated from the measured cutting speed. Therefore, it is not necessary to collect a core specimen from a concrete structure and to carry the collected core specimen into the test room as in the case of obtaining the compressive strength using a compressive strength tester. The concrete strength of the structure 65 can be estimated.

  Moreover, since the concrete strength of the concrete structure 65 is estimated by forming the hole 70 in the concrete structure 65, only the surface strength can be estimated unlike the rebound hardness method, which is high. Concrete strength can be estimated with accuracy.

  In the above description, the grindstone bit 55 having the core hole 59 at the eccentric position is used. However, although not shown, a grindstone bit having the core hole at the center may be used. A non-type grindstone bit may be used, and even when these grindstone bits are used, the concrete strength can be estimated easily and with high accuracy.

It is the schematic which showed one Embodiment of the punching apparatus by this invention. It is a bottom view of the base of the flame | frame of FIG. It is the sectional view on the AA line of FIG. It is sectional drawing of the grindstone holder of FIG. It is a perspective view of the grindstone bit of FIG. It is sectional drawing of the grindstone bit of FIG. 5, Comprising: It is explanatory drawing which showed the state of the drilling operation | work with respect to a concrete structure. It is the perspective view which showed the modification of the grindstone bit. It is explanatory drawing which showed the relationship between the cutting time and the cutting depth with respect to the concrete structure of the grindstone bit in predetermined indentation force. It is explanatory drawing which showed the relationship between pressing force and the cutting speed calculated | required from the relationship between the cutting time of FIG. 8, and the cutting depth. It is explanatory drawing which showed the relationship between the cutting speed calculated | required from the relationship between the pressing force of FIG. 9, and the cutting speed, and concrete strength.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Punching device 2 Frame 3 Base 4 Recess 5 Communication hole 6 Connection port 7 Space 8 Packing 9 Through-hole 10 Guide 11 Bush 12 Escape hole 13 Support shaft 15 Propulsion means 16 Moving table 17 Mounting jig 20 Actuator 21 Pressure supply source DESCRIPTION OF SYMBOLS 22 Piping 23 Switching valve 25 Displacement detection means 26 Laser displacement meter 27 Reflector 29 Power supply 30 Drive means 31 Drive motor 32 Drive shaft 33 Chuck 34 Grinding stone holder 35 Mounting shaft 36 Communication hole 37 Joint 38 Inflow hole 39 Supply path 40 Holder body 41 Attachment part 45 Fluid supply means 46 Storage tank 47 Drainage channel 48 Pump 50 Control means 55 Grinding stone bit 56 Grinding stone body 57 Drilling surface 58 Attachment part 59 Core hole 60 hole 61 Slit 65 Concrete structure 70 Hole

Claims (5)

A concrete strength estimation method for estimating the concrete strength of an existing concrete structure,
The cutting speed of the grindstone bit is measured while cutting the concrete structure with a constant driving force by the grindstone bit, and the concrete strength of the concrete structure is estimated based on the measured value. Estimation method.   By manufacturing a plurality of concrete structures with different concrete strengths in advance and cutting each concrete structure while changing the propulsive force with a grindstone bit, the relationship between the pressing force of the grindstone bit against each concrete structure and the cutting speed is obtained. 2. The method for estimating concrete strength according to claim 1, wherein the concrete strength of the existing concrete structure is estimated based on the relationship between the determined pressing force and cutting speed.   When cutting the concrete structure with a grindstone bit, a cylindrical grindstone bit having a flat perforated surface, driving means for rotating the grindstone bit, propulsion means for propelling the grindstone bit, The method for estimating concrete strength according to claim 1 or 2, wherein a drilling device comprising a driving means and a control means for controlling the propulsion means is used. A concrete strength estimation system for estimating the concrete strength of an existing concrete structure,
A cylindrical grindstone bit having a flat perforated surface, drive means for rotationally driving the grindstone bit, propulsion means for propelling the grindstone bit, control means for controlling the drive means and the propulsion means Using the drilling device provided,
In the control means, the relationship between the pressing force of the grindstone bit and the cutting speed for a plurality of concrete structures having different concrete strengths obtained in advance is stored as information, and based on the stored information. A concrete strength estimation system for estimating the concrete strength of the existing concrete structure.   A cylindrical grindstone bit having a flat perforated surface, drive means for rotationally driving the grindstone bit, propulsion means for propelling the grindstone bit, control means for controlling the drive means and the propulsion means And the control means stores, as information, the relationship between the pressing force of the grindstone bit and the cutting speed for a plurality of concrete structures having different concrete strengths obtained in advance, and based on this information, the existing A drilling device configured to estimate a concrete strength of a concrete structure.

Images