JP2003300787A - Rupture prevention method for concrete - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rupture prevention method for concrete which irradiates the surface of a concrete cured body with a laser beam, forms a hole part, discharges steam from the hole part, and thereby prevents the rupture of the concrete at a fire. <P>SOLUTION: In this rupture prevention method for concrete, a laser oscillator A, an optical fiber B whose one end is connected with the laser oscillator and the concrete cured body D which is irradiated with the laser beam C from the other end of the optical fiber B are disposed. Therein, the laser beam C oscillated from the laser oscillator A is applied to the surface of the concrete cured body D via the optical fiber B to form the hole part E. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing explosion of concrete during a fire.

[0002]

2. Description of the Related Art In a concrete structure, water contained in concrete is overheated and vaporized during a fire.
This vaporized water may cause the concrete to rapidly expand and explode. In particular, high-strength concrete has a dense structure, water contained therein is unlikely to evaporate, and the concrete may explode like a steam explosion.

As a method of preventing the explosion of this concrete, fibers such as synthetic resin which are melted by heat are mixed into the concrete, and the fibers are melted by the heat at the time of fire to create a gap, and the steam inside the concrete is created from the gap. There is known a method of releasing the above, a method of applying lath containing mortar on the surface of the concrete to prevent the temperature inside the concrete from rising, and a method of preventing the generation of water vapor at the time of overheating.

[0004]

However, in the concrete in which the fiber is mixed, it is difficult to form a gap unless the temperature inside the concrete rises to melt the fiber. Since it is difficult for the temperature to rise, it is difficult for the fibers to melt, and there is a problem that the concrete may explode before a gap is formed depending on the composition of the fibers.

Further, in the method of applying lath containing mortar or the like on the concrete surface, a certain amount of film thickness is required in order to prevent evaporation of water inside the concrete,
There is a problem that the construction cost is increased at the same time as the construction days.

Further, the above method has a problem that it is difficult to perform explosion proof treatment on an already constructed concrete structure.

Therefore, the present invention has been made in order to solve such a problem, and it is possible to easily prevent the explosion of concrete, and also to prevent the explosion of existing structures. Provide a method of preventing explosion of

[0008]

That is, the invention according to claim 1 uses a laser oscillation device to irradiate a laser beam onto the surface of a hardened concrete body to form a hole, and in the event of a fire, the hole is formed. Is a method for preventing explosion of concrete, characterized in that residual moisture and water vapor inside the hardened concrete are discharged to prevent explosion of the hardened concrete.

The invention according to claim 2 is the method for preventing explosion of concrete according to claim 1, characterized in that the concrete hardening body is irradiated with laser light from the laser oscillation device through an optical fiber. is there.

The invention according to claim 3 is further provided with an irradiation direction changing means for changing an irradiation position of the irradiated laser beam. It is a method of preventing explosion of concrete.

The invention according to claim 4 is the method for preventing explosion of concrete according to any one of claims 1 to 3, which prevents the existing concrete structure of the concrete hardening body from exploding. is there.

According to such a method for preventing explosion of concrete, the holes are formed by using the laser beam, so that in case of fire, residual moisture and water vapor inside the hardened concrete are discharged from the holes to prevent the explosion of concrete. Can be prevented. Further, by irradiating the surface of the hardened concrete with the laser light emitted from the laser oscillator through the optical fiber, the holes can be easily and accurately formed with desired dimensions and intervals. Further, if the irradiation direction changing means is provided at the tip of the optical fiber extending from the laser oscillating device, it becomes possible to irradiate the laser light to an arbitrary place / site without moving the laser oscillating device itself. Further, by using the concrete explosion prevention method, it is possible to install the existing concrete structure for preventing explosion.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 (a) is a plan view showing a state before irradiating a laser beam on the surface of a hardened concrete body,
FIG. 1B is a plan view showing a state where the surface of the hardened concrete is irradiated with laser light. As shown in FIG. 1A, a hole forming device for carrying out the method for preventing concrete explosion according to the present invention comprises a laser oscillator A and an optical fiber B having one end connected to the laser oscillator A.
Composed of and. Then, as shown in FIG.
Forming a hole E on the surface of the concrete hardened body D by oscillating a laser from the laser oscillation device A and irradiating a laser beam C from the tip of the optical fiber B toward the surface portion of the target concrete hardened body. You can
Here, the laser oscillating device A oscillates laser light having a wavelength of 1.06 μm, which can be transmitted by the optical fiber B.
A d: YAG laser is used.

Next, a method of preventing explosion of concrete thus constructed will be described. FIG. 2A is a perspective view showing an opening method of the hole E on the surface of the hardened concrete,
FIG. 2B is a perspective view showing a state where the hole E is formed on the surface of the hardened concrete D by the opening method shown in FIG.

As shown in FIGS. 1 (a) and 2 (a),
The laser oscillating device A is turned on to oscillate with the intensity of the laser light C weakened, and the optical axis of the laser light C is aligned with the place where the hole E is formed on the surface of the hardened concrete D. Then, as shown in FIGS. 1B and 2A, the intensity of the laser beam C is increased to form the hole E on the surface of the hardened concrete D. Here, for example, in the case of forming a hole E having a diameter of 1 mm and a depth of 10 mm, the light intensity is expressed as laser light C emitted from the laser oscillator A.
Is at least 30W energy density of the irradiated part
The energy for irradiating the surface of the hardened concrete D at 100 / cm ² or more needs to be 100 J or more.

Then, the laser beam C is averaged to 150 at the location where the hole E is formed on the surface of the hardened concrete D.
When the irradiation is performed for about 10 seconds with the output of W, the hole E is formed.

After the hole E is formed on the surface of the hardened concrete D, the intensity of the laser beam C is once lowered to move the irradiation portion of the optical fiber B as shown in FIG. 2 (a). After the irradiation location is determined, the intensity of the laser beam C is increased and the hole E is provided on the surface of the hardened concrete D.
This operation is repeated to form a plurality of holes E on the surface of the hardened concrete D as shown in FIG.

In this way, according to the hardened concrete body D having the predetermined number of rear portions E formed therein, even if the hardened concrete body D is overheated in the event of a fire, the water vapor generated inside the hardened concrete body D can be removed from the holes. It can be discharged from E.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a configuration diagram showing the second embodiment. As shown in FIG. 3, the hole forming device includes a laser oscillating device A, an optical fiber B having one end connected to the laser oscillating device A, and a mirror G for changing the laser light C in an arbitrary direction. ing. Then, after irradiating the hardened concrete D1 with the laser light B to form the hole E, the mirror G is rotated at a desired angle in the direction of the hardened concrete D2 to change the irradiation direction of the laser light B, and the concrete The hole E is formed on the surface of the cured body D2.

Here, the mirror G, as shown in FIG.
It is provided perpendicularly to the fixed base F, and is rotatably supported by a rotary shaft H to the left and right. This mirror G can change the laser beam C emitted from the optical fiber B in the direction of the concrete hardened body D1 or the concrete hardened body D2 provided at an arbitrary position. The rotation method of the mirror G is It does not matter whether it is automatic or manual, and it is prevented from being deformed by the laser light C.

Next, a method of preventing explosion will be described. Figure 3
As shown in, the laser oscillator A is turned on, the laser light C transmitted from the laser oscillator A through the optical fiber B is reflected in the direction of the concrete hardened body D1 irradiated by the mirror G, and the hole portion is formed. Form E. And
After forming the hole E on the surface of the hardened concrete D1, the mirror G is rotated so that the laser beam C can be irradiated in the direction of the hardened concrete D2, and the hardened concrete D
A hole E is formed on the surface of 2. The relationship between the intensity of the laser beam C and the hole E is the same as the condition shown in the first embodiment.

Thus, the surface of the hardened concrete D1 is irradiated with the laser beam C to form the hole E, and then the mirror G is rotated to irradiate the surface of the hardened concrete D2 with the laser beam C to form the hole. Part E can be formed,
Increase work efficiency. Further, by adjusting the irradiation direction of the laser light C reflected by the mirror G, the hole E can be formed on the surface of the hardened concrete without moving the laser oscillator A and the optical fiber B. The work efficiency of forming the part E can be improved.

As described above, in the method of preventing explosion of concrete of the present invention, the hardened concrete D is irradiated with the laser beam C from the laser oscillator A through the optical fiber B to form the hole E, and then the optical fiber B is formed. Move and move the irradiation point of laser light C, and harden concrete D
A plurality of holes E are formed on the surface of the. As a result, even if the hardened concrete body D is overheated at the time of fire, the water vapor inside the hardened concrete body D is discharged from the hole E, and thus the explosion of concrete can be prevented.

Further, by providing the mirror G at the tip of the optical fiber B, without moving the optical fiber B,
Holes can be provided on the surface of hardened concrete,
The efficiency of the work of forming the hole E can be improved.

Moreover, it is possible to take measures against the explosion of concrete to existing concrete structures such as columns, walls and bridges of buildings.

In the embodiment of the present invention, the laser oscillating device A is the Nd: YAG laser, but the present invention is not limited to this, and the same effect can be obtained by using an iodine laser or the like. You can

Further, instead of the mirror G, a plurality of optical fibers B may be provided so that the plurality of optical fibers B are sequentially switched for each irradiated portion of the hardened concrete D.

Further, the present invention can be applied to hardened concrete in general, and can be applied to all kinds of concrete such as lightweight concrete, heavy concrete, high-strength concrete, ultra-high-strength concrete, and ordinary mortar.
It can be applied to all kinds of mortar such as lightweight mortar, resin mortar, polymer cement mortar, joint mortar, pasting mortar, and various cement products.

The diameter, the depth and the number of the holes E in the embodiment of the present invention do not limit the present invention, and the intensity of the laser beam C can be changed according to the surface area and the thickness of the hardened concrete D. It is possible to change and form an appropriate hole portion E for the hardened concrete D.

Further, the device configuration shown in the embodiment is not limited to the present invention, and the same effect can be obtained even if the device configuration is combined with a dolly or the like to move the entire device.

【The invention's effect】

INDUSTRIAL APPLICABILITY The present invention can provide a method for preventing explosion of concrete, which can easily prevent explosion of concrete and also can prevent explosion of concrete that has already been constructed.

[Brief description of drawings]

FIG. 1 (a) is a plan view showing a state before irradiating a surface of a hardened concrete with laser light. (B) It is a top view showing the state where the surface of the hardened concrete was irradiated with laser light.

FIG. 2 (a) is a perspective view showing a method for opening a hole E on the surface of a hardened concrete body. (B) It is a perspective view showing the state where hole E was formed in the surface of hardened concrete D by the opening method shown in Drawing 2 (a).

FIG. 3 is a plan view showing a configuration of a second embodiment.

[Explanation of symbols]

A: Laser oscillator B: Optical fiber C: Laser light D: Hardened concrete D1 ... Hardened concrete D2: Hardened concrete E: Hole F: Fixed base G: Mirror H: rotation center axis

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2E001 DE01 EA01 HA04                 3C069 AA04 BA08 CA07 EA05                 4E068 AF01 CA09 CB05 CD12 CE03                       CE08 DB11                 4G028 GA03

Claims (4)

[Claims] 1. A laser oscillator is used to irradiate the surface of a hardened concrete body with laser light to form holes.
A method for preventing explosion of concrete, characterized in that residual water or water vapor inside the hardened concrete is discharged from the hole at the time of fire to prevent explosion of the hardened concrete. 2. The method of preventing explosion of concrete according to claim 1, wherein the hardened concrete is irradiated with laser light from the laser oscillator through an optical fiber. 3. The method of preventing explosion of concrete according to claim 1 or 2, further comprising irradiation direction changing means for changing an irradiation position of the irradiated laser light. 4. The method of preventing explosion of concrete according to claim 1, wherein explosion of an existing concrete structure of the hardened concrete is prevented.