JPS63563A - Concrete casting method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for placing concrete that can significantly reduce water in concrete after placement, particularly surplus water inside the concrete. .

<Conventional technology>Kui> The strength of concrete is determined by the water-cement ratio.
Therefore, it is known that the smaller the amount of water, the stronger concrete can be obtained.

However, in actual concrete, a large amount of water is required when pouring compared to the amount of water required to obtain the design strength.

The reason for this is that if concrete is mixed with only the amount of water required to obtain the design strength, smooth movement and workability (walkability) will be reduced during the transport stage up to the formwork. It is from.

Therefore, reducing excess water for the purpose of achieving good concrete placement results in the creation of separated concrete structures of poor quality.

For this reason, concrete is mixed using a considerably larger amount of water than is required for the original hydration effect.

However, excess water is not only unnecessary after pouring is completed, but also the space where water exists causes drying shrinkage and freezing and thawing, which is a major cause of future concrete deterioration. .

In order to solve these problems, a method has been developed in which the formwork is made of water-permeable cloth to drain excess water to the outside.

However, excess water does not move around freely inside the concrete, so draining water only from the formwork
The effect is only to remove the water on the surface of the plate, and the excess water inside is not improved at all.

If water on the surface is removed in this way, but water inside remains as it is, for example, the degree of drying shrinkage will be different between the inside and the surface, which will eventually cause clutter. .

In other words, it is not possible to produce a concrete structure in a uniform state by using a cloth formwork to remove only surface moisture.

OBJECTS OF THE INVENTION The present invention was made in order to improve the above-mentioned problems, and an object of the present invention is to provide the following method for placing concrete.

(a) Concrete pouring that can be mixed with an amount of water that is easy to work with until the completion of concrete pouring, and after the pouring is completed, excess water that is not necessary for hydration can be removed. Installation method: A method of placing concrete that not only improves the density of the concrete surface, but also positively drains excess water inside the concrete and improves the durability of the entire structure. 〉Concrete construction method that allows construction of structures with accurate shapes and dimensions without bending or deforming as would be the case when fabric formwork is used〉Construction of the present invention〉With reference to the drawings, An embodiment of the present invention will be described.

〉 Filter Retraction Section The filter retraction section 1 is a pipe with one end closed and the other end open.

A large number of small drainage holes 2 are opened in the side surface of this filtering part 1.

Further, the outside of the filtering section 1 is covered with and fixed with a filter material 3 made of a fibrous sheet, a water-permeable nonwoven fabric, a wire mesh, or the like.

Therefore, all of the drainage holes 2 are covered with the filter material 3.

By configuring the filter material 3 to be replaceable with respect to the filtration part 1, a new filter material 3 can be installed each time it is used.

〉Suction mechanism A suction mechanism is connected to the filtration part 1.

This suction mechanism is composed of a water suction hose 4 attached to one end of the open side of the filtering section 1, and a vacuum pump 5 attached to the other end of this water suction hose 4.

Therefore, by driving the vacuum pump 5, the inside of the filtering section 1 can be brought into a negative pressure state.

Alternatively, as shown in FIG. 3, the drain hose 41 is inserted into the filtering section 1 that does not house the foreshock mechanism 6 or the filtering section 1 that houses the foreshock mechanism 6, and the other end of the drain hose 41 is drained. It is also possible to drain the water collected in the filtration section 1 by connecting it to a pump.

(c) Foreshock mechanism A rod-shaped foreshock mechanism 6 is attached inside or along the outside of the foreshock mechanism filtering section 1.

The foreshock mechanism 6 has the same structure as a commercially available bar-shaped pie break for concrete compaction, and uses, for example, rotating an eccentric weight at high speed, or using a piston, an electromagnet, or a planetary gear to generate vibrations to the outside. It is possible to employ a mechanism that generates this.

When the foreshock mechanism 6 is housed inside the filtering section 1, the filtering section 1 is located outside thereof as a negative pressure chamber.

Furthermore, as shown in FIG. 4, a conventional commercially available surface vibrator can also be used.

That is, it is also possible to use a vibration generator in which a vibration generator is fixed on the board 7 of the surface vibration machine, and a plurality of filtering sections 1 housing the foreshock mechanism 6 are provided downwardly protruding from the lower surface thereof.

Or, instead of integrating the two, add filter retraction part 1 every other line,
It is also possible to adopt a structure in which the foreshock mechanism 6 is provided to protrude downward.

Furthermore, as shown in FIG. 5, a plurality of filtering sections 1 housing the foreshock mechanism 6 described above may be fixed to the tip of an arm 8 of a heavy machine with a crawler, and every other filtering section 1 and foreshock mechanism 6 are fixed. You can also attach it.

What is shown in FIG. 6 is an example of a structure in which the power of the vacuum pump 5 and the foreshock mechanism are directly fixed to the filtering section 1.

In a structure in which the filtering part 1 and the foreshock mechanism 6 are combined, repair or replacement is easy if both are made removable.

Note that it is also possible to use the retraction portion l and the foreshock mechanism 6 separately, as shown in FIG. 3, without integrating them.

Next, the method of placing concrete will be explained.

Kui> Installation of formwork A conventional and well-known formwork 9 is assembled.

In addition, as the formwork 9, as mentioned above as a known example,
Of course, it is also possible to use a water-permeable formwork with cloth pasted on the inside.

Exit> Placing concrete Concrete is placed by conventionally known methods, such as concrete pumps, chutes, packets, etc.

Kuha〉Foreshock The above-mentioned filtration part 1 is inserted into the concrete.

A foreshock mechanism 6 is fixed inside or outside the filtration ml, but when only vibration is required, by stopping the operation of the vacuum pump 5 of the suction mechanism, only vibration can be applied to the concrete.

By applying vibrations, the water inside the concrete is called out and becomes rapidly fluidized, making it possible to fill every corner of the formwork.

Further, as shown in FIG. 3, when the filtering section 1 and the foreshock mechanism 6 are configured separately, the foreshock mechanism 6 may apply vibrations to the concrete near the filtering section 1.

2) Removal of water from concrete After the concrete is filled in a predetermined position or while the concrete is being moved inside the formwork, the suction mechanism is activated.

Then, the inside of the filtering and retracting part 1 immediately becomes negative pressure, and the water in the surrounding concrete is sucked into the inside through the drainage hole 2 through the filter material 3, and is discharged to the outside.

Therefore, the water-cement ratio of concrete decreases rapidly, and the strength of concrete increases.

In addition, as shown in FIG. 3, when using a drainage pump, the tip of the drainage hose 41 is inserted deep into the filtration part 1 to drain water.

In either case, the filtering part 1 is generally pulled out from inside the concrete before the concrete begins to harden, but in some cases only the filtering part 1 is left inside the concrete and the drainage hose 41 is removed. It is also possible to use a method of draining the concrete for several minutes and pouring mortar or the like after the concrete has hardened.

After the prescribed curing period has elapsed, the formwork is removed and the structure is completed.

Effects of the Present Invention> Since the present invention is as described above, the following effects can be obtained.

<B> Since surplus water exists until the concrete is completely poured, concrete with good walkability,
In other words, it can be treated as concrete that does not separate and is easy to place.

After concrete is poured, the water inside can be drained to ensure only the water necessary for hydration.

Therefore, it is possible to pour concrete that satisfies the conventional contradictory requirements of easy construction but high strength.

In order to achieve the above objectives, there is a method of attaching a material with high water permeability, such as a sheet, to the formwork.

However, such formwork can only drain excess water that comes to the surface; once inside, the water at that location remains largely unaffected.

Therefore, if such a method is used, the degree of drying shrinkage between the inside and surface of the concrete and the frequency of freezing and thawing will differ, so it cannot be said that concrete of uniform quality can be obtained when viewed as a whole.

However, in the method of the present invention, surplus water inside a concrete structure is also actively sucked out using negative pressure, so the water-to-cement ratio inside the concrete structure is sufficiently reduced as well as near the surface. It is possible to obtain ideal concrete with uniform quality.

Kuha〉If concrete has a weak point somewhere, the compressive strength will be determined by the strength of that part.

Therefore, if the quality of the inside and outside of a structure is uniform as in the present invention, the compressive strength of the entire structure will be improved, and the amount of cement can be saved by that amount, resulting in an economical You can get concrete.

[Brief explanation of the drawing]

Figure 1: An explanatory diagram of the filtration part that houses the placement mechanism. Figure 2.3: An explanatory diagram of the concrete placement method. Figures 4 to 6 and other examples. Figure 3:) 1Y long hose.

Claims (1)

[Scope of Claims] A method for placing concrete, which is performed by placing concrete in a formwork, applying vibration to the concrete, and sucking out excess water inside the concrete using negative pressure.