JPH0214161B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a method for forming precast concrete plates such as wall boards, floor boards, and sheet piles.

[Prior art and problems to be solved by the invention]

Conventionally, when forming precast concrete plates, raw materials with a slump of 3 to 7 cm and a water-to-cement ratio of 35 to 45% are used, and a method called horizontal casting, in which concrete is placed so that the surface of the plate is horizontal, is usually used. Ru.

This method is easy to pour concrete, but
Surface finishing requires a lot of work, and each item requires a formwork, and even when using pressurized concrete, it is necessary to pressurize each item one by one. Furthermore, this pressurized concrete is prone to errors in thickness, and also causes bleeding when drained, necessitating drainage treatment.

Although it is not common, a method called vertical casting, in which concrete is poured so that the surface of the board is vertical, has been proposed. In this method, there is also a method in which a large number of partition plates are arranged and a large number of partition plates are arranged at the same time. However, in this method, the depth of the formwork is deep, making it difficult to place the concrete, and a particular problem is that the concrete raw materials may separate during pouring, resulting in non-uniform quality. Further, in the case where partition plates are arranged, the intervals between the partition plates are fixed and pressure cannot be applied in the thickness direction.

By the way, the applicant has previously developed a method of mixing the water necessary for mixing mortar and concrete in the form of solid granular ice in order to improve the strength, homogeneity, etc. of low-water cement. [Special application 1986-
No. 205037 (Special Publication No. 63-53924)] Then, a raw material with a low water-cement ratio of 15 to 30% is used to form the concrete plate,
In particular, this invention is an attempt to solve the problems caused by the use of the conventional formwork by applying the invention of the above-mentioned application.

[Means for solving problems]

This invention constructs side-by-side groove-like formwork with a depth considerably greater than its thickness by side plates and partition plates, and uses a raw material with a low water-to-cement ratio that is a mixture of aggregate, cement, and water, or a mixture of aggregate, cement, and water. A method in which a raw material mixed with solid phase granular ice is poured into the groove-shaped formwork, and in the formwork, water or water obtained by melting the granular ice and cement undergo a hydration reaction and harden. In particular, this is a method in which the distance between the partition plates is made compressible within a certain range during pressure molding, and the raw material is hardened under pressure in the thickness direction during the hydration reaction.

〔Example〕

FIG. 1 shows an apparatus for carrying out the method of the present invention and its usage state. This groove-shaped formwork A is formed by a side plate 1 and a partition plate 2 to have a depth (D) greater than a thickness (W). )
are quite large, and the required number of them are arranged in parallel. The raw materials used are aggregates consisting of fine aggregates, coarse aggregates, etc., powdered cement such as Portland cement, water or solid granular ice obtained by pulverization, and other suitable admixtures as necessary.
The filling material is mixed by a mixer and has a low water-to-cement ratio of 15 to 30%.

When mixing, powder cement and granular ice are first mixed, and the granular ice is sprinkled with powder cement, and then mixed with aggregate to delay melting of the granular ice.

The above raw materials were placed in a groove-shaped formwork A, and in the formwork A, water or water obtained by melting granular ice and cement were caused to undergo a hydration reaction and hardened, and the raw materials were hardened. The rear formwork A is disassembled and demolded.

Furthermore, when concrete is placed at the joint between the side plate 1 and the partition plate 2 for pressure forming, a clearance 8 is created as shown in FIG.
When pressurizing, the space W1 between the partition plates 2 is configured to be compressible within a certain range of dimensions, and the thickness of the concrete plate that can be obtained by the hydraulic jacks 4 that come into contact with the partition plates 2 at both ends is determined. Apply pressure in the horizontal direction. In addition, if you want to remove it from the pressurizing device early for curing, attach the long bolts 3 to the formwork after pressurizing as shown in Figure 3.
It is possible to maintain the pressing force by inserting the

Figure 4 shows a case in which a hollow concrete plate is formed by placing a core 5 with a circular cross section in a groove-shaped formwork A, and Figure 5 shows a case in which a core 6 with a trapezoidal cross section is placed and a concave groove is formed on one side. This is the case when forming a concrete plate with

〔Effect of the invention〕

The present invention has the above-mentioned structure, and uses raw materials with a low water-to-cement ratio, and in particular, uses granular ice in a solid state as water.Since the raw materials are mixed in a solid state, the mixing becomes homogeneous and easy, and the ratio of water to cement is low. Water-cement ratio can be used. In addition, since the raw material has a low water-to-cement ratio, it does not separate even when placed in a formwork, so it is possible to cast vertically, allowing multiple concrete plates to be formed at the same time. In addition, since the spacing between the partition plates can be compressed within a certain range during pressure forming, it is possible to press the parallel groove-shaped formwork at the same time, and it is also possible to pressurize at high pressure and for a long time, making it possible to Accuracy can be ensured without causing errors in plate thickness dimensions that tend to occur in compressed concrete. In particular, unlike conventional pressure molding, drainage is not generated or is extremely small, so various problems caused by drainage can be solved.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the state in which the invention is implemented; Fig. 2 is a detailed sectional view of the joining joint between the side plate and the partition plate; Fig. 3 is a partially cut away cross-sectional view of the joint of the side plate and the partition plate; and Fig. 3 shows the state in which the formwork is pressurized. It is a perspective view of a held state and is shown in cross section with a part cut away. FIGS. 4 and 5 are perspective views of the core in use, with a portion cut away and shown in cross section. 1... Side plate, 2... Partition plate, 3... Long bolt,
4... Hydraulic jack, 5, 6... Core.

Claims (1)

[Scope of Claims] 1 A groove-shaped mold is formed in which the side plates and the partition plates are arranged in parallel with a depth considerably greater than the thickness, and the interval between the partition plates is flexible within a certain range, and the aggregate and A raw material with a low water-to-cement ratio, which is a mixture of cement and water, is poured into the grooved formwork, and the raw material is pressurized in the thickness direction, and the water and cement undergo a hydration reaction within the formwork. A method for forming a concrete plate, which is characterized by hardening the concrete plate. 2 The side plates and the partition plates are arranged in parallel with a depth considerably greater than the thickness, and the gap between the partition plates is flexible within a certain range to form a groove-like mold, and the aggregate, cement, and solid phase particles are A raw material with a low water-to-cement ratio in which ice is mixed and cement is sprinkled around the granular ice is poured into the grooved form, the raw material is pressurized in the thickness direction, and the mold is A method for forming a concrete plate, characterized in that water obtained by melting the granular ice and cement are caused to undergo a hydration reaction and harden within a frame.