JPH07247570A - Surface protection method of pc driving waterproof material - Google Patents

Abstract

PURPOSE:To provide a state, wherein water can be absorbed to effect swelling, only after being in contact with a cast concrete without being unnecessarily swelled even if being in contact with water. CONSTITUTION:When a PC panel driving form 16 for constituting an inside form of an underground wall is manufactured, during the time at which cast concrete C is not cured, a swelling waterproof material 12 containing bentonite is applied to the surface of the concrete. And thereafter, emulsion of polymer which is soluble in alkali but insoluble in water is applied to the surface of the agent 12 and cured to form a waterproof film 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for protecting a PC driven waterproof material using bentonite as a swellable waterproof material.

[0002]

2. Description of the Related Art As one of the waterproofing methods for the underground outer wall, a PC driving waterproofing method provided with a swelling waterproof material such as bentonite has been proposed.

In this construction method, a swellable waterproof material containing bentonite is integrated on the entire surface of, for example, a PC-casting mold, and the waterproofing material is built facing the cast-in-place concrete surface side. By assembling and then pouring concrete, the layer of the waterproof material is laminated in a sandwich state between the pouring concrete and the form, and the form remains as it is after pouring. It remains and forms part of the underground wall.

In this structure, when water penetrates from the underground through cracks in the cast concrete, the water absorbs and swells when it reaches the waterproof material layer, and the swelling action further intrudes water. Water resistance can be secured by preventing this. Further, in this method, since the waterproof material layer can be integrally provided at the same time when the PC driving form is molded,
There is an advantage that the construction is easier than the case where the waterproof material is constructed on site.

[0005]

However, in this construction method, when the surface of the waterproof material is contacted with water due to rainfall or water sprinkling before pouring concrete, it absorbs and swells unnecessarily. In the state, it is easily peeled off by physical external force, and the desired effect cannot be exerted,
Handle it with care so that it does not come into contact with water. It should be noted that it may be covered with a waterproof cover such as a film, but it requires time and effort such as peeling off one by one at the time of installation.

The present invention solves the above problems, and its purpose is not to swell unnecessarily even when it comes into contact with water in a normal state, but to swell due to water absorption only when it comes into contact with concrete for pouring. It is intended to provide a surface protection method for a waterproof material for implantation into a PC, which is made possible.

[0007]

In order to achieve the above object, the present invention provides a swelling waterproof material coating containing bentonite on the surface of PC concrete, and then applying alkali to the surface of the swelling waterproof material coating. It is characterized by forming a waterproof film of a polymer emulsion which is soluble and insoluble in water.

[0008]

According to the above construction, since the waterproof film is insoluble in ordinary water, it acts as a protective film for the swellable waterproof material even if rain or other water comes in contact with the surface.

When the strong alkaline water contained in the cement comes into contact with the waterproof coating due to the concrete pouring, the coating is dissolved and the swellable waterproof material and the cast concrete come into direct contact with each other to function as a waterproof material.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. 1 (a) to 1 (c) show a PC according to the present invention.
The procedure of an example in which the surface protection method of a driving waterproof material is applied to the production of a PC plate driving mold is shown. First, as shown in (a), concrete C is poured inside the molding frame 10. Next, at the initial stage of the hydration reaction in which the concrete C solidifies to some extent, as shown in (b), the swellable waterproof material 12 made of a mixture of bentonite and a binder is sprinkled and uniformly applied with a trowel or the like.

Examples of the binder include various polymers that can be emulsified, such as natural or artificial rubber and other polymers. Examples of artificial rubber include polybutadiene, SBR, SBR, ABR, 2-divinylpyridine-styrene-butadiene, chloroprene and isoprene.

Other emulsifiable polymers include polystyrene, polyethylene, vinyl chloride copolymers, vinylidene chloride polymers, acrylate polymers, polyvinyl acetate, vinyl acetate copolymers, vinyl acetate. Ethylene-based copolymer, acrylate-styrene-based polymer,
Various resins such as polyurethane and epoxy are listed.

The mixing ratio of bentonite and the polymer is 15 parts by weight to 12 parts by weight of bentonite based on 100 parts by weight of the polymer emulsion having a solid content of 20 to 70%.
A mixture obtained by mixing 0 parts by weight and kneading is used.

When the weight ratio of bentonite is less than 15 parts by weight, the water swelling property of bentonite is impaired, and when it exceeds 120 parts by weight, the adhesion to the concrete 12 is impaired and exfoliation occurs. Because it is easy to do
It is desirable to set within the above range.

Next, after hardening the concrete C, the waterproof material 12
A polymer emulsion that is soluble in alkali and insoluble in water is applied to the surface of the. This polymer emulsion is, for example, a copolymer of an organic compound having an unsaturated group such as methyl methacrylate disclosed in JP-B-57-14285 and an organic acid having an unsaturated bond such as acrylic acid,
Alternatively, it is made of a silane-based penetrating absorption inhibitor, etc., and is cured as shown in FIG.
The integral waterproof coating 14 is formed on the surface of 2.

After the above work is completed and the concrete C is cured, it is removed from the molding frame 10 to complete the PC plate driving mold 16. The waterproof coating 12 protects the waterproof material 12 even if water hits the surface due to rainfall or water sprinkling in the completed state of the product.

This PC plate driving mold 16 is shown in FIG.
As shown in, a cast-in-place concrete 20 is poured into a space a that is used as an inner formwork of the underground wall and is formed between the mountain retaining wall 18 and the formwork 16.

At this time, the waterproof coating 14 facing the concrete 20 is dissolved in contact with the strongly alkaline water of the concrete 20 and dispersed on the contact surface side of the concrete 20, as shown in FIG. Only the waterproof material 12 directly contacts the surface of the concrete 20.

Therefore, after the concrete 20 is hardened, only the swellable waterproof material 12 is integrated between the concrete 20 and the casting mold 16 in a sandwich state. After the construction, when water seeps out from the side of the mountain retaining wall 18 along cracks in the concrete 20, the water is taken into the waterproof material 12, and the waterproof material 12 absorbs this water and swells in the in-plane and out-of-plane directions. The swelling pressure prevents water from entering the driving mold 16 side as the inner wall.

Of course, it is also possible to use the casting form 16 as an outer form to be built on the ground side and to pour in-situ concrete between it and the weir plate arranged inside. is there.

Further, a sheet material such as a non-woven fabric containing bentonite is attached to the inner surface of a mold for forming a PC plate mold in advance, and concrete is placed in the mold to swell and waterproof the surface. It is also possible to manufacture a PC plate formwork in which materials are integrated.

Further, in the above-mentioned embodiment, an example in which the method for protecting the surface of the PC driving waterproof material according to the present invention is applied to the manufacture of the PC plate driving mold, is not limited to the plate, and the PC is not limited to the plate. It is not limited to the case where it is used for general purpose, but it is soluble in alkali when general swelling waterproof material is driven into the part that comes in contact with soil at the time of molding with general PC such as culvert, segment, and fume pipe. It is also possible to apply or spray an emulsion of a water-insoluble polymer. This makes it possible to prevent the swellable waterproof material coating from swelling even when the molded PC member is stored in an open field, which facilitates on-site management.

[0023]

As described above in detail with reference to the embodiments, in the surface protection method for a waterproofing material for PC implantation according to the present invention, it does not unnecessarily swell even when it comes into contact with water,
Since it can be swelled by absorbing water by contacting the cast concrete, a swellable waterproof material is integrally provided on the surface of P.
It is suitable as a method for temporarily protecting the waterproof material until the C concrete is placed. Moreover, in this invention,
Since a waterproof cover such as a film is not required, it is possible to reduce the time and effort required for removal during construction.

[Brief description of drawings]

1 (a)-(c) are examples of P according to the present invention.
It is explanatory drawing which shows the construction procedure of a C driving formwork.

FIG. 2 is a cross-sectional view showing a structural example of an underground wall using the same driving form.

[Explanation of symbols]

 10 Formwork 12 Swellable Waterproof Material 14 Waterproof Coating 16 PC Placing Formwork 20 Cast-in-place Concrete

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Asami 570-22 Himekawahara, Arai City, Niigata Prefecture (72) Inventor Masao Kawahara 1-10-4 Minamidai, Kawagoe City, Saitama Prefecture Within Shokubeton Japan Co., Ltd. (72) Inventor Mineo Takasu 1-10-4 Minamidai, Kawagoe City, Saitama Prefecture Within Shokubeton Japan Co., Ltd. (72) Inventor Miki Aoyama 4-640 Shimoseido, Kiyose City, Tokyo Inside Obayashi Engineering Research Institute Co., Ltd. (72) Inventor Yoshi Hayashi Original 4-640 Shimo-Seido, Kiyose-shi, Tokyo Inside the Obayashi Technical Research Institute, Inc. (72) Inventor Haruka Haruka, 4-640, Shimo-Seido, Kiyose-shi, Tokyo Inside the Obayashi Technical Research Institute (72) Inventor, Ito Mitani Kiyose, Tokyo 4-640 Ichishita Seido, Obayashi Institute of Technology Ltd. (72) Inventor Etsunori Tamura Chiyoda-ku, Tokyo Tatsukasa-cho 2-chome address 3 Co., Ltd. Obayashi Corporation Tokyo in the Head Office (72) inventor Okamoto, Hideo, Chiyoda-ku, Tokyo Tsukasamachi 2-chome address 3 Co., Ltd. Obayashi Corporation Tokyo in the head office

Claims (1)

[Claims] 1. A swellable waterproof material coating containing bentonite is formed on the surface of PC concrete, and then a water-insoluble polymer emulsion waterproof coating is formed on the surface of the swellable waterproof material coating. P which is characterized by
Surface protection method for C-type waterproof material.