JP2764529B2 - Treatment of vertical seams in concrete - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a vertical seam provided on a floor slab, a beam, a wall or the like when a concrete structure is divided and constructed.

[0002]

2. Description of the Related Art Joints between old and new concretes which occur during construction may be a weak point of a structure unless the treatment is carefully performed. For this reason, conventionally, the surface of the hardened old concrete was roughened with a wire brush or the like and washed with water, and after sufficient water was supplied, new concrete was poured to bring the old and new concrete into close contact. However, when the old concrete is completely hardened, it is difficult to chemically bond the old and new concrete together. Especially at the vertical joint, the separation of new concrete material
Water tended to collect and the strength tended to be insufficient.

[0003] Therefore, a setting retarder is applied to the inner surface of a joint formwork of old concrete to cast concrete, and high-pressure water is sprayed on the joint surface after demolding to wash away latencies and the like, A method of exposing the unhydrated portion of the cement particles therein and casting the new concrete so that the cement paste in the new concrete adheres thereto has also been adopted.

[0004]

However, even if a setting retarder is used, it is impossible to chemically bond the entirety of the old and new concrete at the joint surface with the new concrete part due to the bleeding occurring at the joint surface. Poor curing may occur. Also inject high-pressure water onto the joint surface after demolding
In the treatment method for vertical joints, mortar, etc.
Can not be drained as it is
After-treatment of water had to be considered. Also, wash water
At sites where the water must be drained as it is,
There is a problem that this processing method cannot be adopted
Was. On the other hand, without using a setting retarder, multiple
Arrange the projections and cast concrete, and
After forming multiple recesses on the vertical joint surface of the
Cast concrete so that the two mechanically engage
There was also an intended vertical seam treatment method. Conventional projection
Rubber, cloth, synthetic resin, etc.
It has been used, but in the case of a water-absorbing material such as cloth
Has the drawback that cement can penetrate and make demolding difficult.
Was. Non-water-absorbing rubber and synthetic resin solid projections
When forming, the peeling from concrete is good
However, the weight of the sheet material is heavy and the installation work is complicated
There was a disadvantage. In addition, these rubber and synthetic resin
It is also possible to reduce the weight by making the projection hollow
However, when pasting to the joint form with the protruding body cut,
There was a drawback that concrete entered the void.

[0005] The present invention solves the above-mentioned problems, and combines new and old concrete firmly without using a setting retarder, and forms a plurality of recesses in the vertical joint surface of the old concrete by a simple construction method.
It is intended to form thereby reliably improve the strength of the hit seam, yet provides a method of processing vertical strokes seam concrete that can suppress bleeding in the striking seam.

[0006]

In order to solve the above-mentioned problems, a method for treating a vertical joint of concrete according to the present invention is provided. In the seam treatment method, air is enclosed inside the dome-shaped or cylindrical protrusion
To heat the polyethylene foam cushioning material for packaging
Cut so that the protruding body with the open section is closed
After that, this foam cushioning material is connected to the vertical joint surface of the old concrete.
The concrete is cast by sticking it to the inner surface of the joint formwork that forms the joint, forming a plurality of recesses on the vertical joint surface of the old concrete, and a flat surface surrounding the recesses, and then uncured new concrete. It is characterized by casting concrete.

[0007]

According to the method for treating a vertical joint of concrete according to the present invention, a plurality of concave portions are formed in a vertical joint surface of old concrete, new concrete is cast therein, and a joint portion in which both are mechanically engaged. Is what you do. Since the attachment surface of the old and new concrete at the vertical joint is three-dimensional, the attachment area is larger than that of a flat joint surface. Further, by forming irregularities on the vertical joint surface of the old concrete, moisture (breathing) that rises on the joint surface can be retained, thereby preventing the joint surface from decreasing in strength. Most of the protrusions are air
The foam cushioning material made of
Easy and heat cutting when cutting long objects into a predetermined shape
Because the device is used, even if the protrusion is cut, it is closed at the same time
be able to. Therefore, the cut sheet
There is a fear that concrete may enter the hollow part even if
There is no such thing, and demolding can be performed smoothly.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an explanatory view of a method of treating a vertical seam joint of concrete according to the present invention. A joint formwork 2 is erected at the vertical joint of a concrete member (hereinafter referred to as old concrete 1) to be constructed in advance, and has a dome-shaped or cylindrical protrusion 3a for sealing air on its inner surface 2a. Is pasted. The sheet material 3 is a non-water-absorbing soft sheet made of polyethylene foam cushioning material for packing (air cap).
Top) . The sheet material 3 is stuck to the joining formwork 2 using a double-sided tape or a pneumatic driving tool, but when the protrusion at the end is cut, concrete enters the portion. Is cut into a required shape using a heating and cutting instrument so as to close the projection. Concrete is poured into the inside of the form (FIG. 1A), and after a predetermined curing period has elapsed, the joint form 2 and the sheet material 3 are removed.

[0009] In the vertical joint 1a of the old concrete 1, a concave portion 1b in the form of a protrusion 3a and a flat portion 1c surrounding the concave portion 1b are formed. Next, when a concrete member (hereinafter referred to as new concrete 4) to be constructed later is cast (FIG. 1 (b)), the vertical concrete joint 4 on the new concrete 4 side is formed.
In a, a convex portion 4b fitted to the concave portion 1b is formed, and a joint portion mechanically meshes with each other.

[0010] The adhesion surface of the new and old concrete has a larger adhesion area than the flat joint surface. Therefore, the bending tensile strength also increases, and the reliability of the joint surface improves. Also, by forming unevenness on the vertical joint surface 1a of the old concrete 1, moisture rising on the joint surface can be retained, and hardening failure caused by excess moisture at the upper part of the joint surface of the new concrete 4 can be prevented. it can.

The specific shape of the sheet material 3 is shown in FIGS.
As shown in FIG. 5, a plurality of dome-shaped or cylindrical protrusions 3a having a diameter d and a height h from the sheet flat portion 3b are projected with a minimum adjacent interval p. In a bending strength test of a test piece performed to confirm the effectiveness of the processing method of the vertical seam joint using the sheet material 3, d = 3 cm and h = 1.1c.
The protrusions 3a of m, p = 3.2 cm arranged in a staggered manner as shown in FIG. 3 (type A) have the highest strength, and the setting retardant is applied to the old concrete side without using the sheet material 3. The strength was about 1.6 times that of the test specimen (type C). The ratio of the area occupied by the projections 3a to the entire plane of the sheet material 3 was about 0.37.
Also, d = 0.95 cm, h = 0.25 cm, p = 1.1
cm with the same arrangement of the protrusions 3a (type B)
Is about 1.5 times that of a test piece with only a setting retarder applied.
Showed twice the strength. On the joint surface of the type C specimen, a poorly hardened portion, which is considered to be caused by breathing, was found on the new concrete side, but not on type A and type B. This indicates that the uneven portion of the sheet material 3 is also effective in preventing breathing.

The specimen for bending strength test used in the above test has a square section of 150 mm on a side and a total length of 530.
The new and old concrete joints are provided at the center of the specimen, and a partitioning plate to which a setting retarder is applied or a sheet material 3 is attached is erected near the center of the test sample mold.

[0013]

As described above, according to the present invention, a plurality of recesses are formed in the vertical joint surface so that both the old and new concretes are mechanically engaged with each other. Bending tensile strength increases. Further, by forming the unevenness on the vertical joint surface, the water that rises on the joint surface can be retained, and an excess of water above the joint surface can be prevented.
Therefore, the hardening failure of the joint concrete is also eliminated. Again
High pressure water is sprayed on the joint surface after demolding because no setting retarder is used
You don't have to. Therefore, in the vertical joint of the present invention,
Can be adopted regardless of the site environment.
You. In addition, polyethylene air bubbles for packing to enclose air inside
Since the cushioning material is used, it is lightweight and easy to handle. or
Using a heated cutting instrument, the protrusions with the cut section open simultaneously
So that it can be cut off
Easy removal from concrete without the possibility of concrete entering the hollow part
It is.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a method for treating a vertical seam of concrete.

FIG. 2 is a perspective view of a sheet material.

FIG. 3 is a plan view of a sheet material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Old concrete 1a Vertical joint surface 1b Depression 1c Flat part 2 Joint form 2a Inner surface 3 Sheet material 3a Projection 3b Sheet flat part 4 New concrete 4a Vertical joint 4b Convex part

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hirofumi Watanabe 6-3-1, Takinogawa, Kita-ku, Tokyo Inside Kawada Construction Co., Ltd. (56) References JP-A-5-33485 (JP, A) 5-12545 (JP, U) Japanese Utility Model 3-115762 (JP, U) Japanese Utility Model 3-40440 (JP, U) Japanese Utility Model Utility Model 63-200050 (JP, U) Japanese Utility Model Utility Model 6-20752 (JP, U) U) (58) Field surveyed (Int.Cl. ⁶ , DB name) E04G 21/02 103

Claims (1)

(57) [Claims] 1. A method of processing vertical strokes seam when splicing hit a cured new concrete uncured vertical strokes seam of the old concrete, in the interior of the dome-shaped or cylindrical protrusions
Heats polyethylene foam cushioning material for packing air
The protruding body with the cutting part opened is closed using a cutting instrument
After this, the foam cushioning material is
A concrete is cast by attaching it to the inner surface of a joint formwork that forms a vertical joint surface, forming a plurality of recesses on the old concrete vertical joint surface and a plane portion surrounding the concave portion, and then A method for treating a vertical joint of concrete, which comprises placing uncured new concrete.