JPH07136917A - Structural concrete and machining method of structural concrete and grinding wheel used for machining structural concrete - Google Patents

Abstract

PURPOSE:To increase the minimum cross section of a corner section of a groove on a surface of concrete and improve the strength of the corner section by providing the groove on the surface of concrete and chamfering the corner section of the groove. CONSTITUTION:A grinding wheel 3 provided with grindstones 8, 11 is rotated to cut a surface 14 of a hardened concrete 13 and start machining of a groove 15. Further, cutting is continued while lowering the grinding wheel 3 to deepen the groove 15 to start chamfering B of a corner section C in the upper section of the groove 15 by a section of radius of curvature R 12. Thus, the grinding wheel 3 is lowered by a certain amount to complete machining of chamfering B of the groove 15 and the corner section C in the upper section of the groove 15. Consequently, the minimum cross section of the corner section C increases due to the chamfering B, and its strength can be improved. As a consequence, the corner section C is not chipped even if load is applied from the outside, and flatness and appearance of the surface 14 can be maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete laid as a foundation of a building and the like, and a structural concrete and a structural concrete in which a groove is provided for limiting a portion where cracking occurs due to shrinkage stress during drying. The present invention relates to a grinding wheel used for a working method and a working tool for structural concrete.

[0002]

2. Description of the Related Art FIG. 3 is an enlarged cross-sectional view of a conventional structural concrete in which a groove 103 having a predetermined depth is linearly provided on a surface 102 of hardened concrete 101. Groove 103
Indicates that the surface 102 is cut by a disk-shaped grinding wheel (not shown).

The concrete 101 cracks due to shrinkage stress during drying. However, if the groove 103 is provided in advance, the cracking can be limited to the bottom side of the groove 103 and the exposure to the surface 102 can be prevented.

[0004]

In the above-mentioned conventional example, as a result of the cutting work by the grinding wheel, the upper corner portion 1 of the groove 103 is formed.
Since 04 is a substantially right angle, the minimum cross-sectional area of the corner portion 105 in the oblique direction is small and the strength is not sufficient. Therefore, when a load is applied to the corner portion 105, the corner portion 105 is chipped due to internal stress, and the surface 10 of the concrete 101 is
There was a problem that the flatness and appearance of No. 2 were impaired.

The present invention is intended to solve the above problems, and an object of the present invention is to provide a structural concrete in which the strength of a corner is increased, a method for processing the structural concrete, and a grinding wheel used for the processing of the structural concrete. There is.

[0006]

In order to achieve the above object, the present invention provides structural concrete in which a groove is provided on the surface of concrete, and chamfers are provided at the corners of the groove.

Further, the present invention is characterized in that, while grooving the hardened concrete surface, chamfering is performed on the corners of the groove.

Further, the present invention comprises a disk-shaped plate, an outer peripheral grindstone provided on the outer periphery of the plate, and a pair of inner peripheral grindstones provided on both side surfaces of the plate. The distance between the exposed side surfaces is set to be larger than the thickness of the outer peripheral grindstone, and a rounded or inclined surface is provided along the circumferential direction at the boundary portion between the outer peripheral surface of the pair of inner peripheral grindstones and the exposed side surface.

[0009]

According to the present invention, the minimum cross-sectional area of the corner is increased and the strength thereof is improved.

Further, according to the present invention, the grooving process and the chamfering process can be performed by one processing operation.

Further, according to the present invention, the outer peripheral grindstone carries out grooving work, and the rounded or inclined surfaces of the pair of inner peripheral grindstones carry out chamfering work.

[0012]

1 is a vertical sectional view showing an embodiment of the present invention. In FIG. 1, reference numeral 1 is a rotary shaft, and the rotary shaft 1 is rotated by a drive source such as a motor (not shown).

A disk-shaped grinding wheel 3 is attached to the tip of the rotary shaft 1 by a nut 2. The grinding wheel 3 has a grooved grinding wheel 4 and a pair of chamfered grinding wheels 5 fixed to both side surfaces of the grooved grinding wheel 4.

The grooved grinding wheel 4 has an outer peripheral grindstone, for example, a grindstone 8 fixed along the outer circumference of a plate 7 made of a plate having a hole 6 in the center. The sectional shape of the grindstone 8 is substantially rectangular.

The outer diameters of the pair of grinding wheels 5 for chamfering are set to be the same, and are smaller than the inner diameter of the grinding wheel 8. The pair of chamfering grinding wheels 5 includes a plate 10 having a hole 9 in the center thereof.
An inner circumference grindstone, for example, the grindstone 11 is fixed along the outer circumference of the.

The distance L between the exposed side surfaces 11A of the grindstone 11 is set to be larger than the thickness T of the grindstone 8, and a predetermined diameter along the circumferential direction is provided at the boundary between the outer peripheral surface 11B of the grindstone 11 and the exposed side surface 11A. Is formed, that is, the recess 12 is formed. That is, the edge A of the radius 12 is located on the extension line of the side surface 8A of the grindstone 8. The inner diameters of the holes 6 and 9 are the same.

The grindstones 8 and 11 used in this embodiment are generally used for grooving concrete and have abrasive grains such as fused alumina, silicon carbide and diamond.

A method of using the grinding wheel 3 will be described. Concrete 1 laid and hardened on the axis of a rotary shaft 1 (not shown) that rotates in a predetermined direction as a foundation floor of a building
3 is parallel to the surface 14.

Next, when the grindstone 3 is lowered as shown by the arrow D in FIG. 1, the grindstone 8 cuts the surface 14 to start grooving.

When the grinding wheel 3 is further lowered, the groove to be processed becomes deeper, and the chamfering of the corner of the groove upper portion is started by the radius 12. When the grinding wheel 3 is lowered by a certain amount and then stopped, the machining of the groove 15 and the chamfer B of the corner C at the upper portion of the groove 15 as shown in FIG. 2 is completed.

In this embodiment, the minimum cross-sectional area of the corner C is increased by the chamfer B, and its strength is improved. Therefore,
Even if a load is applied from the outside, the corner C will not be chipped,
The flatness and appearance of the surface 14 can be maintained.

Further, a grindstone provided with a flat inclined surface (not shown) may be used instead of the radius 12. in this case,
Although the shape of the chamfer to be processed is flat, the same effect as above can be obtained.

Further, in this embodiment, since the groove digging process and the chamfering process can be performed by one machining operation, the machining efficiency is high, and the machining time can be shortened and the machining cost can be suppressed.

The present embodiment can also be used as structural concrete for constructing walls of buildings and the like.

[0025]

As described above, according to the present invention, in the structural concrete in which the groove is provided on the surface of the concrete, the chamfer is provided at the corner portion of the groove, so that the minimum cross-sectional area of the corner portion becomes large due to the chamfering. Strength is improved. Therefore, even if a load is applied from the outside, the corners are not chipped, and the flatness and appearance of the surface can be maintained.

Further, according to the present invention, while grooving is performed on the surface of the hardened concrete, the chamfering is performed on the corners of the groove. Therefore, the grooving and chamfering can be performed by one machining operation. Therefore, the processing efficiency is good, and the processing time can be shortened and the processing cost can be suppressed.

Further, the present invention has a disk-shaped plate, an outer peripheral grindstone provided on the outer periphery of the plate, and a pair of inner peripheral grindstones provided on both side surfaces of the plate. The distance between the exposed side surfaces is set to be larger than the thickness of the outer peripheral grindstone, and a rounded or inclined surface is provided along the circumferential direction at the boundary portion between the outer peripheral surface of the pair of inner peripheral grindstones and the exposed side surface.

For this reason, while grooving with the outer peripheral grindstone, chamfering is performed at the corners of the groove by the rounded or inclined surfaces of the pair of inner peripheral grindstones, so that the grooving can be performed with one machining operation. And chamfering can be performed. Therefore, the processing efficiency is good, and the processing time can be shortened and the processing cost can be suppressed.

[Brief description of drawings]

FIG. 1 is a front sectional view of an embodiment of the present invention.

FIG. 2 is a partially enlarged front cross-sectional view showing an embodiment of the present invention in a state where the groove and chamfering process is completed.

FIG. 3 is a front sectional view showing a groove of conventional concrete.

[Explanation of symbols]

 13 concrete 14 surface 15 groove 7 plate 8 grindstone (outer peripheral grindstone) 11 grindstone (a pair of inner peripheral grindstone) 11A exposed side surface 12 are L distance T thickness C corner B chamfer

Claims (3)

[Claims] 1. A structural concrete in which a groove is provided on the surface of the concrete, wherein a chamfer is provided at a corner portion of the groove. 2. A method for working structural concrete, characterized in that while chamfering is performed on the surface of hardened concrete, chamfering is performed on the corners of the groove. 3. A disk-shaped plate, an outer peripheral grindstone provided on the outer periphery of the plate, and a pair of inner peripheral grindstones provided on both side surfaces of the plate, and exposed side surfaces of the pair of inner peripheral grindstones. The distance between each other is set to be larger than the thickness of the outer peripheral grindstone, at the boundary between the outer peripheral surface of the pair of inner peripheral grindstones and the exposed side surface, the structural concrete is provided with a rounded or inclined surface along the circumferential direction. Grinding wheel used for processing.