JP2011032842A - Concrete body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a concrete body having a crack-inducing joint for preventing a filler filled into the crack-inducing joint from falling from the crack-inducing joint. <P>SOLUTION: The concrete body opens on the surface (wall surface 2) thereof. In the concrete body (reinforced concrete wall 1) wherein the crack-inducing joint 3 formed with a recessed groove extending along the surface is provided, the crack-inducing joint 3 has a width dimension (a) of the opening in the recessed groove which is smaller than the width dimension (b) of the bottom surface in the recessed groove. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a concrete body having a crack-inducing joint.

Reinforced concrete walls begin to dry and shrink immediately after being placed, which causes cracks in the walls. Since this crack is caused by the physical properties of the concrete, it is inevitable and cannot be avoided. In recent years, high-strength concrete has been used even in general apartment buildings, and cracks are more likely to occur due to its compositional properties.
Therefore, as shown in FIG. 7A, there is known a reinforced concrete wall 101 having a wall surface 115 with a crack-inducing joint 100 for inducing a crack in order to concentrate the crack at a specific place where the crack is predicted (Patent Document). 1 etc.).
In addition, various deterioration factors such as chloride ions, oxygen, water, etc. enter the concrete from the outside through the cracks induced by the crack-inducing joints, causing corrosion of the reinforcing bars and deterioration of the durability of the wall. In order to prevent this and to improve the appearance, the crack-inducing joint 100 is usually filled with a filler 102 such as a mortar for repairing the crack as shown in FIG. 7B. It is known (see Patent Document 2).

JP 2007-231573 A Japanese Patent Laid-Open No. 11-117407

As shown in FIG. 7, the crack inducing joint 100 is formed by a groove having a concave cross section, and the width dimension 111 of the opening 110 of the groove is larger than the width dimension 113 of the bottom surface 112 of the groove. That is, the conventional crack inducing joint 100 has a trapezoidal cross-sectional shape that is wide on the wall surface 115 side and narrow on the bottom surface 112 side. This is to make it easier to release a mold bar installed on a concrete formwork (not shown) in order to form a crack-inducing joint 100.
However, in the crack-inducing joint 100 where the width dimension 111 of the opening 110 of the groove is larger than the width dimension 113 of the bottom surface 112 of the groove, even if the filler 102 is filled in the crack-inducing joint 100, at the time of an earthquake, When compressive force or tensile force is applied to the crack-inducing joint 100, the filler 102 peels from the crack-inducing joint 100 and falls. When the filler 102 is peeled off from the crack-inducing joint 100, it becomes a cross-sectional defect of the reinforced concrete wall 101, which may have an adverse effect on the structure.
The present invention has been made in view of the above problems, and provides a concrete body provided with a crack-inducing joint capable of preventing the filler filled in the crack-inducing joint from being peeled off from the crack-inducing joint.

  The concrete body according to the present invention is a concrete body provided with a crack-inducing joint formed by a groove that opens to the surface of the concrete body and extends along the surface. The crack-inducing joint is a width of the opening of the groove. Since the dimension is smaller than the width dimension of the bottom surface of the concave groove, the filler filled in the crack-inducing joint can be prevented from peeling off from the crack-inducing joint.

The expanded sectional view of the crack induction joint part of a reinforced concrete wall (embodiment 1). The perspective view of the reinforced concrete wall provided with the crack induction joint (Embodiment 1). Sectional drawing of the reinforced concrete wall provided with the crack induction joint (Embodiment 1). Sectional drawing which shows the relationship between a type | mold rod and a reinforced concrete wall (Embodiment 1). The figure which shows the method for forming a crack induction joint (Embodiment 1). Sectional drawing which shows the relationship between a type | mold rod and a reinforced concrete wall (embodiment 2). An enlarged cross-sectional view of a crack-induced joint part of a reinforced concrete wall (conventional).

Embodiment 1. FIG.
As shown in FIG. 2, the reinforced concrete wall 1 as the concrete body according to the first embodiment includes a crack-inducing joint 3 formed by a groove that opens to the wall surface 2 and extends along the wall surface 2.
The cross-sectional shape perpendicular to the longitudinal direction of the joints in the crack-inducing joint 3 (hereinafter referred to as the cross-sectional shape of the crack-inducing joint 3) is as shown in FIG. 1 of the concave groove opening 5 that forms the crack-inducing joint 3. The width dimension a is formed in a trapezoidal shape smaller than the width dimension b of the bottom surface 6 of the concave groove.
The cross-sectional shape of the crack inducing joint 3 is, for example, a trapezoidal shape in which the upper base is the width dimension a of the opening 5 of the concave groove and the lower base is the width dimension b of the bottom surface of the concave groove. That is, the crack inducing joint 3 has a trapezoidal cross-sectional shape with a narrow wall surface 2 side and a wide bottom surface 6 side.
As shown in FIGS. 2 and 3, the crack-inducing joint 3 is provided on both wall surfaces 2; 2 of the walls facing each other or only on one wall surface 2. In FIG. 3, reference numeral 4 denotes a reinforcing bar disposed in the wall of the reinforced concrete wall 1.

A method for forming the crack-inducing joint 3 will be described.
The formation of the crack-inducing joint 3 is performed by forming a mold plate 21 in which a mold bar 10 for forming the crack-inducing joint 3 is attached to the mold surface 21a that forms the wall surface 2 of the reinforced concrete wall 1 (see FIG. 5A). It is formed using.
As shown in FIG. 4, the mold bar 10 is formed of a first mold bar 11 and a second mold bar 12. The die 10 is formed so that the cross-sectional shape orthogonal to the longitudinal direction is the same as the cross-sectional shape of the crack-inducing joint 3. The mold rod 10 is formed such that the first mold rod 11 and the second mold rod 12 are detachable.

The cross-sectional shape of the first mold bar 11 is such that the lower base length a1 and the upper base length b1 are smaller than the width dimension a of the opening 5 of the concave groove, and the lower base length a1> the upper base length b1. It is formed into a trapezoid.
The cross-sectional shape of the second mold bar 12 is such that the lower base length b2 and the upper base length a2 are smaller than the width dimension a of the opening 5 of the concave groove, and the lower base length b2> the upper base length a2. It is formed into a trapezoid.
The mold bar 10 is formed such that the upper base of the trapezoidal cross section is the lower base of the trapezoidal cross section of the first mold bar 11 and the upper base of the trapezoidal cross section of the second mold bar 12, and the lower base of the trapezoidal cross section is the first mold bar 11. The joint surface 13 of the first mold bar 11 and the joint surface 14 of the second mold bar 12 are abutted so as to be formed by the upper base of the trapezoidal cross section of the And the 1st type | mold stick | rod 11 and the 2nd type | mold stick | rod 12 are formed so that attachment or detachment is possible by the connection tools 23 (refer FIG. 5A), such as a nail, a wood screw, and a double-sided tape.

  As shown in FIG. 5 (a), the mold plate in a state where the mold surface 21a of the mold plate 21 that comes into contact with the wall surface 2 and the surface that becomes the upper bottom of the trapezoidal cross section of the mold rod 10 are in contact with each other. 21 and the mold rod 10 are attached with a fixture 22 such as a nail, and two mold plate plates 21 are installed so that the mold surface surfaces 21a face each other across the thickness dimension of the reinforced concrete wall 1. After placing the reinforcing bars 4 between the mold plates 21; 21, ready concrete is placed between the mold plates 21; 21. After the concrete has solidified, first, the fixture 22 that fixes the mold plate 21 and the mold bar 10 is removed, and the mold plate 21 is peeled off from the reinforced concrete wall 1. Thereafter, the connecting tool 23 detachably connecting the first mold bar 11 and the second mold bar 12 is removed, and the first mold bar 11 is removed from the reinforced concrete wall 1 as shown in FIG. . As shown in FIG. 4, the first mold bar 11 is easily removed from the reinforced concrete wall 1 because the lower base length a1 of the trapezoidal cross section located on the wall surface 2 side is longer than the upper base length b1. Can do. Thereafter, as shown in FIG. 5 (c), the second mold bar 12 is removed from the reinforced concrete wall 1. The length b2 of the lower base and the length a2 of the upper base of the trapezoidal cross section of the second die 12 are smaller than the width dimension a of the opening 5 of the concave groove forming the crack-inducing joint 3 as shown in FIG. Therefore, it can be easily removed from the reinforced concrete wall 1. By the above, the reinforced concrete wall 1 provided with the crack induction joint 3 with the width dimension a of the opening 5 of a ditch | groove smaller than the width dimension b of the bottom face 6 of a ditch | groove can be formed in the wall surface 2. FIG. And as shown in FIG.5 (d), the filling 25, such as mortar, is filled in the ditch | groove which forms the crack induction joint 3. FIG.

  According to the first embodiment, the reinforced concrete wall 1 having the crack-inducing joint 3 that can prevent the filler 25 from falling off when the filler 25 is filled in the crack-inducing joint 3 is obtained.

  In general, reinforced concrete seismic walls often require several months from concrete placement to wall finishing work. It often occurs. Therefore, by filling the groove 25 forming the crack-inducing joint 3 with the filler 25 at the time of finishing work, it is possible to suppress cracks appearing on the wall surface 2 and to prevent cracking and peeling of the finishing material. You can also

Embodiment 2. FIG.
You may use the type | mold stick | rod which combined 3 or more type | mold sticks. For example, as shown in FIG. 6, a mold bar 10 in which three mold bars 30, 31, 32 are combined may be used.

  In short, the mold bar 10 can be removed from the wall surface 2 of the reinforced concrete wall 1 after forming the crack-inducing joint 3 in which the width dimension “a” of the groove opening is smaller than the width dimension “b” of the bottom surface of the groove. What is necessary is just to use the type | mold stick | rod 10 formed by the 2 or more type | mold type | mold stick | rod which can be divided | segmented.

  In the above description, the reinforced concrete wall 1 is shown as a concrete body with a crack-inducing joint. It can also be applied to concrete bodies such as walls, breakwaters, and waves.

1 reinforced concrete wall (concrete), 2 wall surface (surface),
3 Crack-induced joint, a width dimension of the opening of the groove, b width dimension of the bottom surface of the groove.

Claims (1)

  In a concrete body with a crack-inducing joint formed by a groove that opens into the surface of the concrete body and extends along the surface, the width of the opening of the groove is the width of the bottom surface of the groove. A concrete body characterized by being smaller than its dimensions.

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