JP2013238415A - Quality evaluation method for concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a quality evaluation method for a concrete structure that does not impair its beauty, that can perform evaluation at the same position repeatedly, that can directly evaluate a cover portion (between a surface and a reinforcement), that does not unnecessarily open a hole having a small diameter, and that does not require extra repair work of filling of mortar.SOLUTION: Nondestructive/micro-destructive inspections are performed on a concrete structure 2 by utilizing a plastic cone hole 9 generated on a skeleton surface of the concrete structure 2. A micro-destructive inspection is performed in the plastic cone hole 9 using a small-diameter core or a drill 10. Alternatively, an air permeability test and a percolation test are performed.

Description

  The present invention relates to a method for evaluating the quality of a concrete structure in which a non-destructive / microdestructive inspection of the concrete structure is performed by utilizing a P-con trace hole generated on the frame surface of the concrete structure.

  Currently, there are three methods for evaluating the quality of concrete structures: a destructive inspection method, a microdestructive inspection method, and a nondestructive inspection method.

Destructive inspection methods include the following.
・ Concrete core test:
Use a boring machine to collect the core. Various tests are performed using the collected core (strength test, chemical analysis, etc.).
・ Hassing test: When conducting chemical analysis not based on core collection, or by piercing the internal reinforcing bars of the frame to check the corrosion status and reinforcement.

The following microdestructive inspection methods are available.
・ Boss specimen:
When a boss form is attached to the structure form in advance and concrete is placed, the boss form is simultaneously filled with concrete and integrally molded. By cutting and collecting the specimen and conducting strength tests and analysis, destructive inspection can be performed without damaging the structure itself.
・ Small diameter core test:
A small-diameter core is collected and tested for strength and analysis. Compared to the concrete core test, destructive inspection can be performed without damaging the structure itself.

Nondestructive inspection methods include the following.
・ Test hammer (rebound hardness method):
The strength is estimated by hitting the concrete surface with a test hammer and measuring the degree of rebound.
・ Ultrasonic method:
Measure the ultrasonic propagation velocity and estimate the dynamic elastic modulus of concrete. In addition, the crack depth and member thickness are measured using ultrasonic propagation time and phase inversion.
・ Electromagnetic wave radar method:
Radiate electromagnetic waves and measure internal conditions (rebar positions, cavities) using reflected waves. The following patent document describes an application of this ultrasonic method as a laser ultrasonic exploration method [irradiating a pulsed laser beam to the exploration target to cause rapid thermal expansion on or near the surface of the exploration target, and This is a method of propagating the expansion strain as an elastic wave (ultrasonic wave) into the object to be searched. By observing elastic waves, it is possible to detect defects in the exploration target and to measure physical properties (Kazuji Yamanaka “Principle and Application of Laser Ultrasound Method” Nondestructive Inspection, Vol. 49, No. 5, p292- 299)].
JP 2002-296244 A

In this patent document 1, the surface of a concrete structure to be diagnosed is irradiated with a pulse laser beam to generate an elastic wave due to thermal expansion, and the surface at the time of irradiation is collimated by a laser interferometer that collimates the surface of the part to be diagnosed. Waves and elastic waves are detected over time, and the presence or absence of internal defects or buried objects in the concrete structure at the diagnosis site is diagnosed from the change in waveform from the detection of the surface wave to the detection of the final elastic wave.
・ Air permeability test (Trent method):
Suction concrete surface and measure air permeability. Until now, in order to measure the air permeability and water permeability of concrete, it was measured using the core and drill holes, so this test has no problems such as scratching the structure.

Patent Document 2 below does not belong to any of the destructive inspection method, the microdestructive inspection method, and the nondestructive inspection method, but attaches a test specimen collection cylinder to a concrete casting mold and collects the test specimen. This is a method for estimating the strength of the concrete structure by testing the specimen taken in the cylinder with a compressive strength tester.
JP 2000-329666 A

  A screening net for taking in only the mortar component is provided in the opening of the specimen collection tube, and concrete is placed in the mold to remove the mold, and after curing for the required age, the specimen is collected. A mortar specimen is taken out from the cylinder, the measured value of the mortar strength of the specimen is obtained by the compressive strength tester, and the strength of the concrete structure is estimated from the measured value.

  The destructive inspection method such as the core test is said to be a method with high test accuracy in that the target structure itself can be evaluated by taking a sample directly from the concrete structure and conducting the test / analysis. The problem is that the object is damaged and the number of samplings is limited accordingly, and the entire structure cannot be evaluated.

  In addition, the non-destructive inspection method is characterized by a wide range of investigations without destroying the structure, and various studies have been made on methods using the torrent method, electromagnetic waves and ultrasonic waves, but the accuracy is still low. There are many inadequate points, and no evaluation method has been established.

  The microdestructive inspection method is located between these two inspection methods and aims to evaluate with high accuracy while minimizing damage to the structure, but there are still few types. Even in the case of microfracture, repair is necessary at the damaged part, and the aesthetics are not lost as the number of test samples increases.

  In summary, the conventional inspection methods are: a. Detract from aesthetics, b. Only the surface portion can be evaluated, c. It is difficult to fix the test equipment (adhesive selection, damage due to anchor drilling, etc.), d. Possibility of complicated recording of test points If marking is made on the housing, there is an inconvenience such as loss of aesthetics.

  In the method of Patent Document 2, a small-diameter hole is opened in the concrete structure after the specimen is collected. However, since the size of the hole is about the same as that of a separator P-conductor that is usually used, There is no effect, and repair work may be done with mortar filling, but it is necessary to make a small-diameter hole in order to collect the specimen, and repair work with mortar filling is required.

  The object of the present invention is to eliminate the inconveniences of the above-mentioned conventional examples, not to impair the aesthetics, and to evaluate at the same place any number of times, and to directly evaluate the cover (between the surface and the reinforcing bar), and unnecessarily small-diameter holes. It is to provide a method for evaluating the quality of a concrete structure that does not need to be opened and that there is no need for extra repair work by mortar filling.

  In order to achieve the above-mentioned object, the present invention firstly uses a P-con trace hole generated on the surface of a concrete structure to conduct a non-destructive and micro-destructive inspection of the concrete structure. To perform a microdestructive test using a small-diameter core or a drill, and secondly, to collect a core specimen by drilling with a small-diameter core in a P-con trace hole, and to perform a strength test, and , Neutralization and salt analysis in the depth direction using the core, and third, analysis using drilling scraps obtained by drilling (dry) in P-con trace holes (salt analysis, Neutralization etc.), fourth, insert a bar type scanner into the drilling hole obtained by drilling (dry type) in P-con trace hole, and confirm the internal situation, fifth, Concrete structure using P-con trace holes that occur on the surface of the concrete structure For non-destructive and micro-destructive inspections, a cap with a pipette is connected to a dedicated cap mounting screw and separator to form a water tank in the P-con trace hole, ensuring adhesion between the tank and concrete. Install, fill the tank and pipette with water, measure the amount of water that has penetrated into the concrete with a pipette, and sixth, make use of the P-con trace hole that occurs on the surface of the concrete structure In order to perform nondestructive and microdestructive inspection of concrete structures, a sucker-like stopper is put on the P-con trace hole, and a small-diameter pipe connected to the vacuum pump is pierced into the stopper, and the air in the P-con trace hole The gist is to measure the air permeability coefficient by measuring the flow rate of air during suction.

  The factor that has the most influence on the durability of concrete is the durability on the outer side (cover) than the reinforcing bar. That is, it is important to improve the durability of the concrete in the cover and to correctly evaluate the durability of the concrete structure.

  All conventional nondestructive tests such as Schmidt Hammer, Ultrasonic, and Electromagnetic Waves are surveys from the concrete surface. Even if the strength and the presence of internal voids can be confirmed, durability in the depth direction from the surface toward the reinforcing bar is confirmed. It is not a technique that can be quantitatively evaluated.

  On the other hand, since the P-con is installed on the inner side of the formwork surface, the cured P-con trace hole is in a state where a hole is opened from the concrete surface. The present invention makes it possible to evaluate the durability of the concrete at the cover portion in the depth direction by utilizing this hole.

  In addition, the P-con trace hole is basically filled with exposed steel (separator) such as mortar or cap. Therefore, not only non-destructive but also a micro-destructive test within the range of the P-con trace hole The soundness and durability can be evaluated without impairing the aesthetic appearance.

  It is an effective method for investigating structures that require strong aesthetics, such as exposed concrete for building structures. In addition, since a plurality of places (the number of P-con) can be tested without deteriorating the aesthetic appearance, the durability of the concrete structure can be evaluated with a wide range and accuracy.

  Traceability is facilitated by numbering the P-con with an IC tag or the like.

  According to the third aspect of the present invention, the collected core specimen can be used as a test specimen, for example, by using acetone so as not to be neutralized, and can be evaluated even if time passes after collection. In this way, various analyzes can be performed.

  According to the fourth aspect of the present invention, drill hole scraps are used, and can be evaluated in real time while drilling.

  According to the sixth aspect of the present invention, the test tool can be easily fixed by utilizing the screws of the separator.

  As described above, the quality evaluation method of the concrete structure of the present invention does not impair the aesthetics, can be evaluated at the same place any number of times, and can directly evaluate the cover (between the surface and the reinforcing bar), which is unnecessary. There is no need to carry out repair work by mortar filling without making a small-diameter hole.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present invention, a non-destructive / microdestructive inspection of a concrete structure is performed by utilizing a P-con trace hole generated on the surface of the concrete structure. The P-con trace hole will be described first.

  FIG. 8 is an explanatory view of the formwork construction. In the figure, 1 is a plywood formwork, 2 is a concrete structure formed by this plywood formwork, and plywood before placing concrete forming the concrete structure 2 Formwork 1 is assembled.

  In the figure, reference numeral 3 denotes a (round) separator for supporting the plywood mold frame 1. A mold pipe 4 is vertically arranged as a presser on the outside of the plywood mold frame 1, and a horizontal butterfly pipe 5 is used as the presser. It is fixed by a foam tie (registered trademark) 6 and a three-type rib seat 7.

  A P-con 8 is disposed at the end of the separator 3. The P-con 8 is inserted between the separator 3 and the face plate (plywood formwork 1) to widen the area, so that the face plate is dented by axial force. It is a truncated cone shape made of synthetic resin (plastic).

  A screw hole 8a is provided in the center of the upper bottom portion, and an end screw of the separator 3 is fitted therein, and a screw 8b is protruded from the center of the lower bottom portion, and this screw 8b penetrates the face plate (plywood mold frame 1) to the outside. It protrudes, and the nut part of foam tie (registered trademark) 6 is screwed here.

  The P-con trace hole 9 is a frustoconical hole that remains on the surface of the concrete structure 2 after removing the P-con 8 after mold removal.

  In the first embodiment of the present invention, as shown in FIG. 1, a microdestructive test using a small-diameter core or a drill 10 is performed in a P-con trace hole 9. As an example, as shown in FIG. 2, the core specimen 11 is sampled by drilling with a small-diameter core, and the strength test of the core specimen 11 is performed. For this core removal, the small-diameter core or the drill 10 may be advanced in an oblique direction from the peripheral wall of the P-con trace hole 9 to the back.

  Since the diameter of the P-concrete hole 9 is mainly about 25 to 40 mm, the core using a small-diameter core or the drill 10 and the drill diameter are preferably 5 to 25 mm.

  Further, the core specimen 11 is used to perform neutralization and salt analysis in the depth direction. Such neutralization and salinity analysis can also be performed on the core after the core specimen 11 is collected by drilling using a small-diameter core or drill 10.

  As shown in FIG. 3, when the P-con trace 9 is filled with the mortar 12, the trace after the drilling is similarly filled with the mortar 12, so that the surface of the concrete structure 2 is subjected to a microdestructive test. There is no loss of aesthetics.

  In addition, regarding the P-con 8 to be used, from the viewpoint of ensuring durability in recent years, the threaded portion 3a (made of steel) of the separator 3 remaining inside the P-con 8 may be considered as a target for securing the cover, as shown in FIG. It is desirable to use “Long P-con” as in (a). By using long P-con, durability of concrete closer to the reinforcing bar 13 can be evaluated.

  In addition, if numbering is applied to the P-con 8 using an IC tag or the like, traceability is facilitated.

  Although illustration is omitted as a second embodiment of the present invention, analysis (salinity analysis, neutralization, etc.) is performed using drilling scraps obtained by drilling (dry type) in the P-con trace hole 9. You may make it perform.

  FIG. 4 shows a third embodiment of the present invention. A rod type scanner 22 is inserted into a hole 25 obtained by drilling (dry type) in a P-con trace hole 9, and the internal state is confirmed. The hole 25 was formed by the small-diameter core or drill 10 shown in FIG.

  As described in Japanese Patent No. 4393756, the bar-type scanner 22 is provided with a linear optical system linearly along the longitudinal direction of the cylinder at a part on the cylinder tip side of a cylindrical main body inserted into a previously drilled inspection hole. An imaging unit having an image sensor and having an opening facing the image acquisition surface of the linear image sensor is formed in the cylindrical main body.

  The cylindrical main body is rotated by a predetermined angle in the circumferential direction in the inspection hole, and the hole wall surface illuminated through the light guide along with the rotation is imaged and an image signal acquired by the linear image sensor is interfaced. The image is output to the personal computer 24 or the SD card 23 which is an external drawing processing means via the unit, and a developed image of the hole wall surface is obtained.

  From the developed image of the hole wall surface, neutralization, cracking, and a chloride ion penetration depth test, etc., which are the same as inspecting without a core, can be performed with the same accuracy.

  FIG. 5 shows a fourth embodiment of the present invention. By utilizing the P-con trace holes 9 formed on the surface of the concrete structure 2, the concrete structure is subjected to non-destructive and micro-destructive inspection and water permeability inspection is performed. Is what you do.

  In order to form the P-con trace hole 9 as a water tank, the cap 18 with the pipette 17 is connected to the dedicated cap mounting screw 19 and the separator 3 to close the opening of the P-con trace hole 9 with the cap 18. Secure the tank and concrete and install it.

  A water-stopping material 20 such as an epoxy resin is laid around the screw head 3 a of the separator 3, and the gap between the separators 3 is closed with the water-stopping material 20.

  The water tank and pipette 17 are filled with water 21, and the amount of water penetrating into the concrete is measured using the pipette 17.

  FIG. 6 shows a fifth embodiment of the present invention. By utilizing the P-con trace hole 9 generated on the surface of the concrete structure 2, the concrete structure 2 is subjected to nondestructive / microdestructive inspection. A suction cup-shaped stopper 14 is applied to the opening of the P-con trace hole 9, and a small-diameter pipe 15 connected to a vacuum pump is pierced into the stopper 14 to suck and suck the air in the P-con trace hole 9. Measure the air flow rate and calculate the air permeability coefficient.

  A so-called air permeability test (output method) is performed, and the small-diameter pipe 15 has a tip like a needle and can be pierced through a suction cup 14. The protruding screw head 3a of the separator 3 is protected by a cap 16 such as an epoxy resin, and air sucked from the inside through the separator 3 is blocked.

  The cap 16 forms a flange 16 a around the opening, and the flange 16 a can block the periphery of the screw head 3 a of the separator 3.

It is a vertical side view which shows 1st Embodiment of the quality evaluation method of the concrete structure of this invention. It is a vertical side view which shows the collection state of the core test piece of 1st Embodiment of the quality evaluation method of the concrete structure of this invention. It is a vertical side view of the state embedded in the mortar of 1st Embodiment of the quality evaluation method of the concrete structure of this invention. It is a vertical side view which shows 3rd Embodiment of the quality evaluation method of the concrete structure of this invention. It is a vertical side view which shows 4th Embodiment of the quality evaluation method of the concrete structure of this invention. It is a vertical side view which shows 5th Embodiment of the quality evaluation method of the concrete structure of this invention. It is P comparison long and normal explanatory drawing. It is explanatory drawing of formwork construction.

DESCRIPTION OF SYMBOLS 1 ... Plywood formwork 2 ... Concrete structure 3 ... Separator 3a ... Screw head 4 ... Formwork pipe 5 ... Butter pipe 6 ... Form tie (registered trademark) 7 ... Three-type rib seat 8 ... P-con 8a ... Screw hole 8b ... Screw 9 ... P-conformation hole 10 ... Small diameter core or drill 11 ... Core specimen 12 ... Mortar 13 ... Reinforcing bar 14 ... Suction cup-like stopper 15 ... Small diameter pipe 16 ... Cap 16a ... Flange 17 ... Pipette 18 ... Cap 19 ... Cap mounting screw 20 ... Water stop material 21 ... Water 22 ... Bar scanner 23 ... SD card 24 ... PC 25 ... Hole drilling hole

Claims (7)

  A micro-destructive test using a small diameter core or drill in the P-con trace hole as a non-destructive and micro-destructive inspection of the concrete structure by utilizing the P-con trace hole generated on the frame surface of the concrete structure A quality evaluation method for concrete structures characterized by   The method for evaluating the quality of a concrete structure according to claim 1, wherein a core specimen is sampled by drilling with a small-diameter core at a P-con trace hole, and a strength test is performed.   The quality evaluation method for a concrete structure according to claim 1, wherein neutralization or salinity analysis in the depth direction is performed using the core specimen or the core.   The method for evaluating the quality of a concrete structure according to claim 1, wherein analysis (salt content analysis, neutralization, etc.) is performed using drilling scraps obtained by drilling (dry type) at a P-con trace hole.   The method for evaluating the quality of a concrete structure according to claim 1, wherein a bar-type scanner is inserted into a drilling hole obtained by drilling (dry type) at a P-con trace hole, and the internal state is confirmed.   Using a P-con trace hole on the surface of the concrete structure, nondestructive and micro-destructive inspection of the concrete structure is carried out, and a cap with a pipette is used to form a water tank in the P-con trace hole. Install the cap mounting screw and separator to ensure adhesion between the tank and the concrete, fill the tank and pipette with water, and measure the amount of water that has penetrated into the concrete using a pipette. Evaluation method for quality of concrete structures.   A P-con trace hole on the surface of the concrete structure is used to perform nondestructive and micro-destructive inspection of the concrete structure. A sucker-like stopper is applied to the P-con trace hole and connected to a vacuum pump. A method for evaluating the quality of a concrete structure, characterized in that a small-diameter pipe is pierced into this stopper, the air in the P-con trace hole is sucked, the flow rate of the air when sucked is measured, and the air permeability coefficient is calculated.

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