JPH1193184A - Placing method of concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the filling properties of concrete in the lower section of an anchor plate. SOLUTION: A section from the central section of an anchor plate 10 to an outer circumferential section is filled gradually with superplasticized concrete 16 by the head pressure of the concrete 16 through an inflow port from a funnel 14 for placing. Since the superplasticized concrete 16 is spread continuously while discharging rolled-in air at the time of placing from the outer circumferential section to the outside at that time, no accompanying air is rolled in and no air reservoir is generated under the anchor plate 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for placing concrete on a lower portion of an anchor plate after installing the anchor plate.

[0002]

2. Description of the Related Art For example, when filling concrete under the anchor plate of a seismic isolation device, when constructing with ordinary concrete, a gap is formed under the anchor plate due to generation of bleeding water and initial hardening shrinkage.
After stopping several cm below the anchor plate, it is necessary to fill the gap with non-shrink mortar or the like.

[0003] In addition, when construction is performed using ordinary concrete with an expanding agent added thereto, although it can be filled up to just below the anchor plate, the air entrapped at the time of driving is sealed under the anchor plate, so that a considerable amount of voids are formed. Will be formed.

[0004] Further, in the case of construction using any concrete, compaction work using a vibrator is necessary, but construction under the anchor plate is a difficult task even using a rod-shaped vibrator, and compaction and filling are not possible. There was a problem that it was likely to be sufficient.

[0005]

SUMMARY OF THE INVENTION In view of the fact that concrete with high fluidity has been applied to various structures in recent years for the purpose of labor saving and high quality of concrete work, the inventors of the present application have considered that It is an object of the present invention to solve the above problem by applying fluid concrete to a lower portion of an anchor plate, which is difficult to fill. That is, the present invention
It is an object of the present invention to provide a method for placing high-fluidity concrete capable of improving the filling property in a lower portion of an anchor plate.

[0006]

According to the present invention, there is provided a method for casting concrete under an anchor plate, comprising the steps of arranging an anchor plate having a concrete inflow hole at a central portion thereof, and placing the anchor plate above the inflow hole. High fluidity concrete is supplied from the installation funnel.

[0007] It is desirable to add an expanding agent to the high-fluidity concrete for a foundation portion where the concrete driving height is high.

[0008]

The high-fluidity concrete diffuses from the central portion of the anchor plate to the outer peripheral portion due to the head pressure, and at this time, entrapped air at the time of driving is discharged from the outer peripheral portion to the outside. For this reason, entrained air is not entrained under the anchor plate, and air pools do not occur.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing the shape of a base such as a seismic isolation device, large towers and equipment, a steel tower, and the like.
2 are drilled. The diameter of the inflow hole 12 is 10 to 30
cm so that concrete can flow in without any trouble. In the present invention, the anchor plate 10
The inflow hole 12 is formed at the center of the anchor plate 10, so that there is no problem in terms of stress.

Reinforcing bars (not shown) are arranged inside the concrete base portion 20, and before the concrete is cast, the periphery of the anchor plate 10 is open to the atmosphere.

FIG. 2 is a sectional view of the foundation showing a state in which concrete is being filled. First, the casting funnel 14 is installed on the inflow hole 12 of the anchor plate 10 (FIG. 2 (1)), and the supply of the high fluidity concrete is started (FIG. 2 (2)). The high fluidity concrete 16 has
As shown by arrows in FIG. 1, the head pressure causes the anchor plate 10 to be filled from the center to the outer periphery.

At this time, the high-fluidity concrete 16 discharges the entrained air during the driving from the outer peripheral portion to the outside,
It diffuses continuously (FIGS. 2 (2) to (4)). The high-fluidity concrete 16 is filled into the outer peripheral portion while being in close contact with the bottom surface of the anchor plate 10 (FIGS. 2 (3) to (4)). Therefore, there is no possibility that entrained air is trapped under the anchor plate 10 or air pools are generated. In addition, in addition to the inflow hole 12,
An air vent hole (not shown) may be provided. Hole diameter 10mm
By providing a plurality of air vent holes, the entrained air is discharged more smoothly, and the quality of concrete is improved.

The concrete used in the method of the present invention is not particularly limited as long as it is generally referred to as high fluidity concrete. High fluidity concrete is concrete in which fluidity is remarkably enhanced without impairing the material separation resistance at the time of freshness, and generally has a slump flow value of 50 to 70 cm.

As the admixture for high-fluidity concrete, powders such as cement, blast furnace slag, fly ash and the like, high-performance AE water reducing agents, separation reducing agents and high-performance AE water reducing agents, and combinations with the above, have been used. Seeds are known. From the viewpoint of bleeding suppression, the or type is preferable.

In the method of the present invention, when the concrete driving height is high, the initial hardening shrinkage cannot be ignored. At that time, it is desirable to add an expanding agent to the high fluidity concrete. As the swelling agent, aluminum fine powder and other commonly used swelling agents can be used. The amount of expansion due to the expanding agent is set to an extent that the amount of settlement can be guaranteed, and the amount added is such that the compressive strength of concrete is less affected.

[0017]

Next, an embodiment in which the method of the present invention is applied to a base portion of a seismic isolation device will be described in detail.

(1) Preparation of Concrete Using the materials shown in Table 1, according to the composition shown in Table 2, high fluidity concrete was prepared. The swelling agent was added to an agitator wheel at a ready-mixed plant in order to enhance dispersibility.
Therefore, an attempt was made to obtain a predetermined amount of swelling after arrival at the site by using a delay type swelling agent.

[0019]

[Table 1] Cement: ordinary portland cement, fine aggregate: Kimitsu production crushed sand (S ₁₎ and Isa-producing crushed sand (S ₂₎ mixing sand specific gravity = 2.68, FM = 2.68 · Coarse aggregate: arrowroot Mixed stone of produced crushed stone (G ₁ ) and crushed stone from Isa (G ₂ ) G _MAX = 20 mm, specific gravity = 2.69, FM = 6.60 ・ Admixture (high-performance AE water reducing agent): polycarboxylic acid ・ Separation Reducing agent: water-soluble cellulose ether ・ Swelling agent: aluminum fine powder + special admixture (dispersant)

[0020]

TABLE 2 W / C s / a Unit weight [kg / m ^3] admixtures separation reducing agent expanding agent [%] [%] W C S 1 S 2 G 1 G 2 [C ×%] [g / m ³ ] [L / m ³ ] 41.3 50.2 165 400 601 269 444 442 2.7 300 0.5

Table 3 shows the quality control test results of the high fluidity concrete prepared in the above (1). From Table 3, it can be seen that both the slump flow (SF) and the inflow mortar amount (Fm) satisfied the control values, and that sufficient results were obtained for the compressive strength.

[0022]

[Table 3] Vehicle SF air volume control temperature Fm compressive strength [ N / mm ² ] [No.] [cm × cm] [%] [° C] [mm] Material age 7th Material age 28th 1 59.0 58.5 4.7 17.5 34 33.1 49.5 2 63.0 63.0 4.1 17.0---3 58.0 59.0 3.2 17.5 29 33.3 51.8 4 61.0 60.0 3.0 18.0---5 58.7 57.5 3.1 17.0 28 33.3 54.5

(2) Casting of concrete The high-fluidity concrete prepared in the above (1) was applied to a foundation 20 having a size of 1700 × 2600 × 270 mm at a rate of 30 m ³ / h without using a vibrator. It was constructed at the casting speed. In addition, the size of the anchor plate 10 of the base portion 20 was 1400 × 1400 mm.

When constructed according to the method of the present invention described above, it was observed that the highly fluid concrete was filled smoothly and uniformly. Further, after the poured concrete 16 had hardened, the anchor plate 10 was removed and the filling condition was confirmed. As a result, no unfilled portions due to the reinforcing bars, anchor bolts, and other obstacles were found.

Further, by measuring the area of the concrete surface by tracing the pock on the concrete surface and measuring the area thereof, the proportion of the pock on the concrete surface was measured. As a result, a low rate of 6.27% was obtained. .

[0026]

According to the first aspect of the present invention, when concrete is poured into a lower portion of an anchor plate installed on a base portion such as a seismic isolation device, large towers and tanks and equipment, and a steel tower, the filling property is improved. Can be greatly improved.

Further, it is possible to not only save labor for grouting work, but also to simplify and speed up the construction method by eliminating compaction work using a vibrator, and to reduce the amount of air entrapped at the time of casting. Thereby, there is an excellent effect that high quality of concrete can be achieved.

According to the second aspect of the present invention, the amount of settlement can be reliably ensured even for a foundation where the concrete is driven at a high height. You can enjoy.

[Brief description of the drawings]

FIG. 1 is a plan view showing a shape of a base portion of a seismic isolation device or the like.

FIG. 2 is a sectional view of a foundation showing a state in which concrete is being filled.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Anchor plate 12 Concrete inflow hole 14 Casting funnel 16 High fluidity concrete 20 Foundation

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Masaru Takano 1-8 Tsukudo-cho, Shinjuku-ku, Tokyo Inside the Kumagaya Gumi Tokyo Branch (72) Masahiro Takahashi 2-1 Tsukudo-cho, Shinjuku-ku, Tokyo Co., Ltd. Kumagaya Gumi Tokyo head office

Claims (2)

[Claims] 1. An anchor plate having a concrete inflow hole in the center thereof is provided, and high-fluidity concrete is supplied from a casting funnel installed above the inflow hole. How to cast. 2. The method according to claim 1, wherein an expanding agent is added to the high-fluidity concrete.