JPH0637048B2 - Method for producing acid-resistant concrete pipe - Google Patents

Description

The present invention relates to a method for producing an acid resistant concrete pipe in which a synthetic resin sheet is attached to the inner surface of the concrete pipe.

It has long been known that concrete generally corrodes in an acidic environment. Therefore, it is necessary to line synthetic resin on the inner surface of concrete pipes that are mainly used as sewer pipes or to attach synthetic resin sheets, but concrete and synthetic resin sheets are extremely adhesive. It has poor properties and it has been considered to use an adhesive on the inner surface of the concrete pipe after hardening, or to heat and fuse it, but perfect adhesion cannot be expected and peeling occurs in a short period of time and acid resistant concrete pipe As it is not used as a cause, it may cause damage to the pipeline. In addition, in a concrete pipe lined with synthetic resin, fine holes (pinholes) in the lining material cannot be avoided, and acidic liquids or gases enter between the concrete and the lining material through this pinhole, and in this case also In the meantime, it is no longer used as an acid-resistant concrete pipe, which causes damage to the pipeline.

A method of embedding anchor projections in concrete when concrete pipe is molded while concrete is uncured by using a sheet with many projections for anchors on the back surface of the synthetic resin sheet to improve adhesion Although it is conceivable, since the adhesiveness to concrete is poor as described above, peeling is likely to occur, and moreover, there is a possibility that cracks may occur in the concrete layer from the protruding anchor portion. Due to recent changes in eating habits and the structure of sewer pipes, sediment from mud matter often decomposes in the sewer pipes to generate sulfur dioxide, and this gas reacts with water. The demand for acid-resistant concrete pipes is increasing because it becomes an acidic liquid and corrodes concrete, and the current situation is that we are struggling to take measures against acid-resistant concrete pipes.

The present invention relates to a novel method for producing a concrete pipe provided with such an acid-resistant coating, using an acid-resistant sheet in which a synthetic resin sheet and a bulky fiber fabric are laminated in advance, and the concrete after forming the concrete pipe is used. Is an uncured fiber-fabric bridge that contacts the concrete surface and presses it to embed the bulky fiber-fabric in the concrete and cure it to obtain an acid-resistant concrete pipe coated with a synthetic resin sheet. Thus, an acid-resistant concrete pipe firmly integrated by the method of the present invention is provided.

Then, as the synthetic resin sheet used for this acid-resistant concrete pipe, polyolefin film not using a plasticizer is suitable, and as bulky fiber, a non-woven fabric with a large basis weight is suitable, but pile weaving or the like may also be used. It is desirable to heat-bond the sheets in advance at the time of forming the sheet.

The first embodiment of the method of the present invention will be described with reference to the accompanying drawings.
The figure is an example of a manufacturing method using an air pack,
FIG. 2 shows another embodiment.

In FIG. 1, (1) is an uncured concrete pipe immediately after molding, and the mold is omitted for convenience in the figure, but naturally this concrete pipe (1) is unsolidified, so the mold removal is completed. Not in the formwork. A is a preformed acid-resistant sheet, which has a bulky fiber fabric (3) laminated on a synthetic resin sheet (2) as shown in the enlarged sectional view of FIG. As the synthetic resin sheet (2), a polyolefin film containing no plasticizer is suitable.
After all, a vinyl chloride film containing a plasticizer, a rubber sheet, or the like is inferior in chemical resistance to a polyolefin film, and it is difficult to peel off because it stretches during lamination and contracts when the pressure is released. And the thickness of this sheet is about 0.2 to 5 m / m, which is suitable for processing. As the bulky fiber, a non-woven fabric made of a synthetic fiber having a high basis weight and a high density is suitable, but a pile woven fabric or the like may be used, and a heat fusion is preferable when laminating, but a bulky fiber is used at the time of film forming. It is even better if the fiber layer is extrusion laminated. (8)
Is an air pack and is inserted over the entire length of the concrete pipe (1), and the acid resistant laminated sheet A is placed outside the air pack (8) so that the surface of the bulky fiber fabric (3) is in contact with the concrete (1). It is encapsulated on the outside.

Therefore, in this embodiment, as shown in FIG. 1, the acid-resistant laminated sheet A is formed on the inner surface of the uncured concrete pipe (1).
When the air pack (8) is set and air or water is sent to the air pack (8) (the air supply device is not shown), the air pack (8) expands and the acid-resistant laminated sheet A contacts the inner surface of the concrete pipe (1). By further continuing the air supply, as shown in the enlarged cross-sectional view of FIG. 4, the outer fiber sheet layer (3)
Intrudes into the inner surface of the uncured concrete layer, and the fibers and cement matrix are entangled with each other, and a strong bond can be expected after hardening. The manufacturing method shown in the embodiment of FIG. 1 is suitable for a small diameter pipe having an inner diameter of about 150 m / m to 600 m / m.

Next, the manufacturing method of the embodiment shown in FIG. 2 will be described. The figure shows a concrete pipe (1) on a centrifugal molding machine, which is uncured concrete immediately after molding, and the mold is omitted as in FIG. An acid-resistant laminated sheet A shown in FIG. 3 was wound on the inner surface of the concrete pipe (1) over the entire length of the pipe with a suitable cylindrical body (9) wound with the bulky fiber surface (3) as the surface to insert the acid-resistant laminated sheet When the fiber sheet (3) surface of the laminated sheet A is pressed against the inner surface of the uncured concrete pipe and the pipe making machine (10) is loosely rotated as shown by the arrow, the cylindrical body (9) is moved in the opposite direction as shown by the arrow. When rotated, the fiber layer of the acid resistant sheet A of the cylindrical body (9) penetrates into the concrete, and as shown in FIG. 3, the fibers are entangled with the cement matrix and a strong bond can be expected after hardening. At this time,
Appropriate vibration is given to the cylindrical body (9) so that it fits better with concrete, and in the case of this example, immediately after centrifugal molding, the mold is not removed from the pipe making machine (10), and the coating process is immediately performed. It is also possible to perform, but once removed from the pipe making machine to see the state of hardening of the concrete inner surface and then put again on the pipe making machine several hours later, and in the case of processing according to this example, the pipe inner diameter is 800 m Suitable for large diameter pipes of / m or more.

In the case of the production method of the present invention, although the molding process is extremely simple, by using the synthetic resin sheet (2) and the acid-resistant laminated sheet A made of the bulky fiber fabric (3), the bulkiness is increased. The fibers of the fiber penetrate into the uncured concrete and entangle with the cement matrix, forming a strong joint after hardening, and the acid-resistant concrete pipe obtained after molding is a covering layer compared to the conventional acid-resistant concrete pipe with a covering layer. It can be expected to have sufficient effect as a pipe material for modern sewer construction without peeling.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of the method of the present invention, FIG. 2 shows another embodiment, and FIG. 3 shows a sectional view of an acid-resistant laminated sheet. FIG. 4 is an enlarged view showing the entanglement between the fiber and the cement matrix. (1) …… Concrete pipe, (2) …… Synthetic resin sheet, (3)
…… Bulky fiber fabric, (8) …… Air pack, (9)
…… Steel cylinder, (10) …… Pipe-making machine

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroji Fukumori 49-9 Torigaoka, Totsuka-ku, Yokohama, Kanagawa Prefecture (56) References

Claims (3)

[Claims] 1. After forming a concrete pipe, a laminated sheet A having a synthetic resin sheet and a bulky fiber fabric bonded in advance over the entire length of the inner surface of the pipe while the concrete layer is uncured so that the fiber fabric side is in contact with the concrete surface. Characterized in that an air pack is further inserted into the air bag, air or water is fed into the air pack to expand the air pack, and the fiber portion of the laminated sheet A is pressure-bonded into the uncured concrete layer. Method for producing acid-resistant concrete pipe. 2. A synthetic resin sheet is preliminarily formed over the entire length of the concrete pipe without removing the uncured concrete pipe from the pipe making machine after the concrete pipe has been centrifugally molded and the concrete layer has not yet hardened. The laminated sheet A laminated with the bulky fiber fabric is inserted into a cylindrical body having the bulky fiber fabric surface as a surface, the laminated sheet A is pressed against the inner surface of the concrete pipe, and the laminated sheet is rotated while rotating the pipe making machine. A method for producing an acid-resistant concrete pipe, characterized in that the fiber portion of A is pressure-bonded into an uncured concrete layer. 3. The method of claim 1, wherein after the concrete pipe has been centrifugally molded, the pipe is once removed from the pipe making machine, and temporarily placed again on the pipe making machine depending on the uncured degree of the concrete layer on the inner surface of the concrete pipe. The method for producing an acid-resistant concrete pipe according to item 2.