JPH01203564A - Concrete placing form - Google Patents

Abstract

PURPOSE:To improve durability, by using a cloth sheet of compound filaments of a core sleeve mechanism for a concrete placing form. CONSTITUTION:The cloth sheet 1 of core sleeve type compound filament composition for using polyester or polyolefin for core component, and polyamide for sleeve component is used for the surface of a mold consisting of wooden or metallic porous plates 2, as internal lining material. Then, the form excellent in dimensional stability and durability can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a concrete casting form using a cloth sheet as the form. More specifically, the present invention relates to concrete casting formwork that uses a cloth sheet made of synthetic fiber as the formwork, and which has good dimensional stability and durability and can withstand repeated use over a long period of time.

(Prior Art) Conventionally, methods of using porous materials such as cloth sheets have been known as methods for pouring concrete on slopes and the like. for example,
Unexamined Japanese Patent Publication No. 6″0-26728 (“Protection method for slopes, etc.”)
The publication proposes a method in which a flexible sheet having countless pores that allows water to pass through but does not allow cement particles to pass through is used in a slope protection method. Also, JP-A-61-187
In Publication No. 928 (“Slope Concrete Placement Formwork”),
A formwork has been proposed in which a porous material is pasted on the surface of a weir plate with a plurality of through holes. However, these publications do not specifically describe flexible sheets or porous materials, and fiber sheets generally used for civil engineering materials include fibers made of polyethylene, polypropylene, polyester, polyamide, etc. Woven or knitted fabrics or non-woven fabrics made of synthetic polymers are only well known.

(Problems to be Solved by the Invention) According to studies by the present inventors, when trying to use these conventionally known fiber sheets as formwork for concrete pouring, various drawbacks arise. It was found that it has.

For example, sheets with a high water permeability can generally be obtained from polyolefins such as polyethylene and polypropylene, but the water permeability is too high to be used as formwork, and there is a drawback that even cement particles can pass through. In addition, if an attempt is made to reduce the permeability coefficient to an appropriate level in order to improve this problem, the sheet will become thick, causing the inconvenience that the surface in contact with the concrete will be compressed during concrete pouring and the concrete surface will not be uniform.

The present invention aims to eliminate these drawbacks of conventional concrete casting forms.

(Means for Solving the Problems) The present invention has the following configuration to achieve the above object. That is, it is characterized in that a cloth sheet made of synthetic fibers is used as a material for the formwork or as a material for lining the formwork.

In the present invention, the polyester and polyolefin constituting the core component must have an appropriate viscosity at the spinning temperature determined in relation to the sheath component during spinning. , poly[1,4-cyclohexanediol terephthalate], etc., but in order to ensure dimensional stability after weaving,
It is preferable to use polyethylene terephthalate, polybutylene terephthalate, and poly[1,4-cyclohexanediol terephthalate], and it is particularly optimal to use polyethylene terephthalate, which is economically easily available. Polyethylene, polypropylene, polybutene-1, etc. can be used as the polyolefin, but from the viewpoint of stability during spinning and ease of handling, polyethylene and polypropylene are preferable, especially polypropylene resin, which allows easy selection of spinning temperature. Use is preferred.

In addition, examples of the polyamide constituting the sheath component include nylon 6, nylon 66, nylon 610, nylon 12, aliphatic polyamides such as polyamide condensed with paraaminocyclohexylmethane and dodecanoic acid, polyxylylene adipamide, and polyhexane. Although any aromatic polyamide such as methylene phthalamide can be used, it is preferable to use nylon 6 and nylon 66 from the viewpoint of ease of spinning and economy.

It is important that the form of the composite filament is such that the sheath component exists continuously over the entire circumference of the fiber cross section, and the core component is not exposed. The cross-sectional shape of the fiber may be a normal round cross-sectional shape, and the arrangement and shape of the core component are not particularly limited, and may be single-core, multi-core, round cross-section, irregular cross-section, concentric, or eccentric. However, in order to ensure dimensional stability, a concentric single-core arrangement with a round cross section or a multi-core arrangement with a round cross section is preferred, where stress is not dispersed.

The ratio of the core component to the sheath component is preferably 1=5 to 8:1 in terms of volume ratio, particularly preferably 1:2 to 2:1. If there is too little sheath component, the sheath coating will become too thin,
Thickness unevenness may occur during spinning, making the coating more likely to tear, or the coating may tear due to external stress during weaving. On the other hand, if the core component is too small, these drawbacks will not occur, but the resistance to tensile stress will be low, resulting in a lack of dimensional stability as a screen.

The composite filament is preferably a multifilament having a single filament denier of 8 to 20 d.

(Function) Since the concrete casting formwork of the present invention uses a cloth sheet made of composite filaments with a core-sheath structure,
The formwork has excellent dimensional stability and durability and can be reused several times. In addition, as the strength of the fabric sheet increases, the formwork sheet can be made appropriately thinner, allowing only air (bubbles) and excess water to pass through and discharge without allowing cement particles to pass through, resulting in a uniform surface and high strength. of concrete is obtained. The present invention will be specifically explained below with reference to embodiments shown in the drawings.

(Example) Fig. 1 is an explanatory diagram showing the usage state of the concrete casting form according to the present invention, in which a cloth sheet is pasted on the surface of the formwork made of perforated wood or metal plate. The figure is also an explanatory diagram showing the state of use of the present invention (concrete placement for protection of slopes, etc.), in which the cloth sheet itself is used as a formwork.

Using various filaments and fabrics with different weave densities, the fabric sheet (1) was fixed under tension inside the perforated plate (2) as shown in Figure 1, and the concrete surface condition and fabric after concrete placement and hardening were measured. The surface conditions were investigated and compared. The result is the first
Shown in the table. ξThe perforated board (2) here is plywood (veneer board) 12mm thick, hole diameter 8 plates, hole pitch 99m in length and width.
m was used.

In addition, the permeability coefficient is JI8A1218r constant water permeability test.The constant water permeability test is a composite filament of nylon (sheath) with good permeability and polyester (core) with good dimensional stability, and its single yarn denier is 3 to 20d1. It can be said that multifilament of 10% or less is excellent in terms of strength and dimensional stability. Also, the thickness of the cloth sheet is 0.2~l,
Q mm, the hydraulic conductivity is lXl0” ~ l0XIO
8 cm/sec is the condition for the cloth sheet that meets the purpose of the present invention, which is to remove air and drain excess water during concrete pouring. (Sample A satisfied these conditions, and the results showed that the condition of the concrete surface and fabric surface after curing was extremely good.) Furthermore, the fabric surface observed in Samples B, D, and E was found to be in very good condition. The concrete adhesion is a result of the concrete remaining in the woven structure and the filament surface being exposed to cement.

(Effects of the invention) Since the concrete casting formwork of the present invention uses a cloth sheet made of composite filaments with a core-sheath structure, the formwork has excellent dimensional stability and durability, and the cloth sheet Since there is no concrete adhesion to the surface, it can be reused several times. In addition, as the strength of the fabric sheet increases, the formwork sheet can be made appropriately thinner, allowing only air (bubbles) and excess water to pass through and discharge without allowing cement particles to pass through, resulting in a uniform surface and high strength. of concrete is obtained.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the state of use of the concrete pouring form according to the present invention, in which a cloth sheet is attached to the surface of the formwork made of perforated wood or metal plate. This is an explanatory drawing showing the state of use of the invention (concrete pouring to protect slopes, etc.), in which the cloth sheet itself is used as a formwork.

Claims (1)

[Claims] (1) In concrete casting formwork that uses a cloth sheet made of synthetic fibers as a formwork material or formwork lining material, the composition of the synthetic fibers is such that the core component is polyester or polyolefin, and the sheath component is polyester or polyolefin. Concrete pouring formwork characterized by being a core-sheath type composite filament using polyamide.