JP5042870B2 - Degradation evaluation method for coating material layer - Google Patents

Description

  The present invention relates to a method for evaluating deterioration of a covering material layer such as a fireproof covering material layer applied to a tunnel inner wall surface or the like.

  In shield tunnels, mountain tunnels, etc., diagnosis of the deterioration over time of the fireproof coating layer applied to the inner wall surface of the tunnel, the degree of deterioration after tunnel fire, etc. is performed. The penetration resistance value of the wet fireproof coating layer is measured with a penetration resistance measuring instrument (push-pull gauge) having a needle, and based on this penetration resistance value, (a) the penetration resistance value when the wet fireproof coating layer is healthy And / or (b) an estimated value of compressive strength determined from the correlation between the previously determined penetration resistance value and the compressive strength, and the penetration resistance value ratio and / or Or the method of diagnosing soundness from the estimated value of compressive strength is proposed.

  Moreover, there exist patent document 2, 3 as a prior art document regarding the diagnosis of the deterioration degree of concrete, for example. The invention of Patent Document 2 relates to a method for evaluating the frost damage resistance of a concrete surface layer portion. A tensile tester is connected to a core bored on a concrete surface layer portion to conduct a tensile test. The degree of deterioration is evaluated.

  The invention of Patent Document 3 relates to a method for estimating the deterioration level of an ALC panel in the field. A screw is placed on the ALC panel itself, and the pull-out strength of the screw is measured by a screw pull-out test method (Kenken-type tensile tester). And the degree of deterioration of the ALC panel is estimated from the relationship between the screw drawing strength and the carbonation degree.

JP 2004-294154 A JP 2007-47133 A JP 2003-177083 A

  In the case of soundness diagnosis of wet fireproof coating layers using conventional penetration resistance value or compressive strength, there is not much difference in compressive strength between, for example, 300 ° C and 400 ° C in the damage situation due to small-scale fire, and the soundness evaluation is performed. There were issues such as being unable to do it clearly. In addition, after a small-scale fire, a technique that can easily check the damage situation in a short time in the field is desired.

  The present invention can clearly determine the degree of deterioration of a fireproof coating layer or the like applied to the inner wall surface of a tunnel, etc., and can easily and quickly determine the degree of deterioration using a relatively simple measurement jig on site. An object of the present invention is to provide a method for evaluating deterioration of a covering material layer that can be determined.

  The present invention is applied to the determination of the degree of deterioration of a wet or dry fireproof coating layer or other coating layer applied to the inner wall surface of a tunnel. A relationship between the drawing strength and the degree of deterioration of the covering material layer is obtained in advance, and the degree of deterioration of the covering material layer is determined by comparing with the measured drawing strength. The pulling strength has a large difference depending on the degree of deterioration of the covering material layer as compared with the compressive strength, and the degree of deterioration of the covering material layer can be clearly determined (see Table 1). Further, the degree of deterioration can be easily determined in a short time in the field by a relatively simple measuring jig using a rod-shaped body and a pull-out load meter.

The invention according to claim 1 of the present invention is a method of evaluating the degree of deterioration of the coating material layer of the structure, and embedded the tip of the rod-like member from the surface to the coating material layer to a predetermined depth, the rod-shaped Deterioration of the covering material layer, characterized in that a pulling jig is connected to the head of the body and pulled out, the pulling strength is estimated by the presence or absence of deformation of the head, and the degree of deterioration of the covering material layer is determined from the pulling strength It is an evaluation method.

The invention according to claim 1 of the present invention is a case where the deformation of the head of the rod-shaped body is utilized. The rod-shaped body is made of an easily deformable material such as brass, and is configured such that the head of the rod-shaped body is deformed with a set pulling load (pullout strength). The degree of deterioration can be determined by the presence or absence of head deformation. When the head is deformed, it can be determined that the pulling strength is high, so that the head is healthy. When the head is not deformed, it can be determined that the degree of deterioration is large because the pulling strength is small (see Table 1). Also in this case, the pullout strength has a large difference depending on the degree of deterioration of the covering material layer as compared with the compressive strength, and the degree of deterioration of the covering material layer can be clearly determined. Further, it is only necessary to pull out the rod-like body with a tool, and the degree of deterioration can be easily determined in a short time with a relatively simple measuring jig.

The invention according to claim 2 of the present invention is the deterioration evaluating process according to claim 1, drilled the pilot holes from the surface to the coating material layer to a predetermined depth, greater diameter than the diameter of the lower hole in the lower hole This is a method for evaluating deterioration of a covering material layer, wherein the tip of the rod-like body is pushed in.

  This is a case where the leading end of a cylindrical rod or the like is pushed into the prepared hole so as to obtain a pulling resistance, and a pulling load (pulling strength) corresponding to the degree of deterioration of the coating material layer can be obtained.

The invention according to claim 3 of the present invention is the degradation evaluation method according to claim 1 or 2 , wherein the rod-like body is provided with a male screw at the tip, and is screwed by being rotated. This is a degradation evaluation method.

  This is a case where a pulling resistance is obtained with a screw, and a pulling load (pulling strength) corresponding to the degree of deterioration of the covering material layer is obtained. It may be screwed into a pilot hole having a diameter slightly smaller than the outer diameter of the male screw, or may be screwed directly by a tapping screw method without providing a pilot hole.

The invention according to claim 4 of the present invention is the degradation evaluation method according to any one of claims 1 to 3, wherein the covering material layer is a fireproof covering material layer, and the damage caused by fire is determined from the pullout strength. This is a method for evaluating deterioration of a covering material layer, characterized by determining the degree.

  In this case, the extent of damage caused by a small fire in the tunnel is judged. The relationship between the drawing strength and the fire temperature is obtained in advance, and the fire temperature of the surface layer of the covering material layer can be determined by comparing with the measured drawing strength. Thereby, the presence or absence of replacement | exchange of a covering material layer can be judged easily in the field in a short time.

  In addition, it is a determination of the deterioration degree of the surface layer part of a coating | covering material layer, and in order not to damage a healthy part, the one where the embedding depth of a rod-shaped body is shallow is preferable.

The invention according to claim 5 of the present invention is the degradation evaluation method according to any one of claims 1 to 4 , wherein the diameter of the tip of the rod-shaped body is 3 mm or less. This is a method for evaluating deterioration of a material layer.

  When the covering material layer is judged to be healthy, if the diameter of the hole formed after pulling out the rod-like body is 3 mm or less, it is not necessary to repair the hole, so that a simpler and shorter determination can be made. .

The invention according to claim 6 of the present invention is the deterioration evaluation method according to any one of claims 1 to 5 , wherein the head of the rod-shaped body is a hook, and a pull-out load meter or a pull-out is attached to the hook. A method for evaluating deterioration of a covering material layer, characterized in that the tip of a jig is connected.

  By simply hooking it on the hook of the rod-shaped body, it can be pulled out, and a simpler and shorter determination operation can be performed. In the case of the screw type, a commercially available hanging hook can be used, and a low-cost determination operation can be performed.

  Since the present invention is configured as described above, the following effects can be obtained.

(1) The degree of deterioration of the covering material layer is determined by the pulling strength of the rod-shaped body, and the pulling strength is greatly different depending on the degree of deterioration of the covering material layer compared to the compressive strength. It can be clearly determined.

(2) The degree of deterioration can be easily determined in a short time at the site using a relatively simple measurement jig.

(3) When applied to a small-scale fire in a tunnel, the fire temperature can be determined clearly and simply in a short time, and the presence or absence of replacement of the fireproof coating can be immediately determined.

  Hereinafter, the present invention will be described based on the illustrated embodiment. FIG. 1 is a vertical cross-sectional view showing an example of a method for evaluating deterioration of a coating material layer according to the present invention and an example of a measuring apparatus used therefor.

  In the embodiment shown in FIG. 1, a wet fireproof coating layer 2 is applied to the inner surface of concrete 1 such as a tunnel by spraying with a layer thickness of about 30 mm, for example. The degree of deterioration of the subsequent surface layer portion is easily determined in a short time on site by the deterioration evaluation method of the present invention. In addition, it is applicable not only to a wet type but also to a dry type fireproof covering material layer.

  First, the pilot hole 10 is drilled in the fireproof covering material layer 2 from the surface to a predetermined depth by a drill or the like. The thread hole depth (leg length) of the male screw 11a is 1 of the layer thickness t so as to measure the degree of deterioration of the surface layer portion of the fireproof covering material layer 2 and not to damage the healthy portion of the fireproof covering material layer 2. / 2 or less is preferable.

  A hanging hook 11 is used for a rod-like body as a measurement terminal embedded in the prepared hole 10. The hanging hook 11 includes a male screw 11a at the tip and a hook 11b at the head. The outer diameter of the male screw 11a is slightly larger than the diameter of the lower hole 10, and the lower hole 10 is rotated by human power or an electric tool to be screwed so that a pulling resistance is obtained.

  The pulling load, that is, the pulling strength of the fireproof covering material layer 2 is measured by connecting the tip of the pulling load meter 12 to the hook 11b of the hanging hook 11 and pulling it out. A commercially available load meter (digital force gauge or the like) can be used as the pull-out load meter 12, and a hook 13 is attached to the tip shaft portion so that the hook 13 is hooked on the hook 11 b of the suspension hook 11.

  The relationship between the drawing strength and the degree of deterioration of the fireproof coating layer is obtained in advance through experiments or the like, and the measured value of the pulling load meter 12 and the degree of deterioration are compared and checked to determine the degree of deterioration of the fireproof coating layer 2 (Table 1). reference). In disasters caused by small-scale fires such as in tunnels, the relationship between fire temperature and pullout strength can be used, and the fire temperature can be determined. Thereby, it can be set as a standard of exchange of the fireproof covering material layer 2.

  The deformation of the hook 11b of the hanging hook 11 can be used not only when the pullout strength is measured as described above. For drawing, a tool that can be pulled by being hooked on the hook 11b can be used. In the case of the former measurement, it is preferable to use stainless steel or the like for the hanging hook 11. However, in the case of the latter modification, a relatively easily deformable material such as brass is used and a predetermined pulling load (pulling strength) is used. The hook 11b is deformed. The degree of deterioration can be determined based on whether or not the hook 11b is deformed. When the hook 11b is deformed, it can be determined that the pulling strength is high, so that it can be determined to be healthy. When the hook 11b is not deformed, it can be determined that the pulling strength is small, so that the degree of deterioration is large (see Table 1).

  The tip of the rod-shaped body 11 is not limited to the male screw in the illustrated example, and may be a cylindrical shaft or the like. In this case, the outer diameter of the tip of the rod-shaped body 11 is made slightly larger than the diameter of the lower hole 10 and is pushed into the lower hole 10 so as to obtain a pulling resistance. Further, in the case of a male screw, it can be directly screwed by a tapping screw method without providing the prepared hole 10.

  After the suspension hook 11 is pulled out, a hole remains in the fireproof covering material layer 2. When the fireproof covering material layer 2 is determined to be healthy by the above determination, if the diameter of the hole is large, it is necessary to repair the hole. However, when the diameter of the hole is 3 mm or less, the above-described repair can be unnecessary. That is, when a panel is pasted on the inner surface of the tunnel, since a gap between the panels is allowed to be 3 mm or less, a hole having a diameter of 3 mm or less is also allowed.

  Next, the test piece of fireproof coating material was used for heating at different heating temperatures, the compressive strength after each heating was measured, the deterioration of strength due to the difference in heating temperature was confirmed, and a small amount in the actual tunnel was also measured. An example of carrying out a simple strength determination method according to the present invention that can be immediately applied on the site assuming a scale fire will be described.

(1) Fireproof coating material Binder: Portland cement / alumina cement (strength maintenance and fire resistance)
Aggregate: Alumina-based aggregate, silica-based aggregate, organic aggregate, etc. (fire resistance and strength maintenance)
Fine aggregate: Aluminum hydroxide, calcium carbonate, etc. (endothermic effect, etc.)

(2) Specimen
The above-mentioned coating material was cast and molded into a 40 × 40 × 160 mm JIS formwork and a 500 × 500 × 30 mm formwork, and cured in an environment of 20 ° C. and 60% RH until the age of 14 days.

(3) Test method
A 500 × 500 × 30 mm product is cut to about 250 × 100 mm and heated at a predetermined temperature in an electric furnace together with a JIS molded specimen for 2 hours. The heating temperature was 200 ° C., 300 ° C., 400 ° C., 500 ° C., 600 ° C., and the compression strength comparison with the absolutely dry product dried at 110 ° C. for 24 hours was performed on the JIS mold product.
A 250 x 100 x 30 mm cutting specimen heated at a specified temperature was drilled with a φ2.5 mm steel drill to a depth of 20 mm, three suspension hooks with a diameter of 2.8 mm and a leg length of 12 mm were attached, and the pulling strength was measured. did.

(4) Test results The test results are shown in the following table.

  As is clear from Table 1, the average compressive strength is not significantly different at each temperature, and cannot be clearly discriminated at, for example, 300 ° C. and 400 ° C., which serve as a guide for changing the coating material. On the other hand, in the case of the pullout strength of the present invention, it can be seen that there is a relatively large difference and it can be clearly distinguished.

  In addition, since the modification of the above-mentioned refractory coating material due to the temperature of the organic raw material and the endothermic material starts around 260 ° C., the values near 300 ° C. and 400 ° C. in this confirmation test are considered to be references for replacement.

  Table 2 shows the results of a pull-out test similar to that described above with the hook leg length (screw length) and the diameter of the pilot hole changed.

  It can be seen that even if the leg length of the hook or the diameter of the pilot hole is changed, the present invention can be clearly distinguished.

  Although the above has described the case where the fireproof coating material on the inner wall surface of the tunnel is applied to the degree of damage caused by a small-scale fire, the present invention can also be applied to the determination of the degree of deterioration of other coating materials.

It is a vertical sectional view which shows an example of the degradation evaluation method of a coating material layer of this invention, and a measuring apparatus used for this.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Concrete 2 ... Fireproof coating material layer 10 ... Pilot hole 11 ... Hanging hook (bar-shaped body)
11a ... Male screw (tip)
11b ... Hook (head)
12 ... Pull-out load meter 13 ... Hook

Claims (6)

  A method of evaluating the degree of deterioration of a covering material layer of a structure, wherein a tip of a rod-like body is embedded in the covering material layer from a surface to a predetermined depth, and a drawing jig is connected to the head of the rod-like body. A method for evaluating deterioration of a covering material layer, wherein pulling strength is estimated based on whether or not the head is deformed and the degree of deterioration of the covering material layer is determined from the pulling strength. The deterioration evaluation method according to claim 1 , wherein a hole is drilled in the coating material layer from the surface to a predetermined depth, and a tip of a rod-like body having a diameter larger than the diameter of the hole is pushed into the hole. Evaluation method for deterioration of covering material layer. The deterioration evaluation method according to claim 1 or 2 , wherein a male thread is provided at a tip of the rod-shaped body, and the rod member is rotated and screwed. The deterioration evaluation method according to any one of claims 1 to 3, wherein the covering material layer is a fireproof covering material layer, and the degree of damage caused by a fire is determined from the pullout strength. Layer degradation evaluation method. The deterioration evaluation method according to any one of claims 1 to 4 , wherein the diameter of the tip of the rod-shaped body is 3 mm or less. The deterioration evaluation method according to any one of claims 1 to 5 , wherein the head of the rod-shaped body is a hook, and a leading end of a pulling load meter or a pulling jig is connected to the hook. Evaluation method for deterioration of covering material layer.

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