JPH0420362B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a concrete-based composite pipe that has high rigidity and strength and is chemically resistant.

[Conventional technology and problems]

Conventional concrete pipes have high rigidity and are inexpensive, but they have the disadvantage of lacking chemical resistance.

On the other hand, there are synthetic resin pipes that have excellent chemical resistance and high strength, but these have low rigidity and are expensive, and because they are lightweight, they may float up when buried underground due to groundwater, etc., or when backplanted with earth and sand. It has the disadvantage of being

Therefore, in order to provide chemical resistance to concrete-based pipes that are highly rigid and inexpensive, composite pipes are developed in which a corrosion-resistant layer of resin (e.g., tar epoxy resin, etc.) is formed on the inner or outer surface or both the inner and outer surfaces of the concrete layer after hardening. However, during the hardening process of the formed concrete pipe, the liquid contained inside the concrete pipe is deposited on the surface of the concrete pipe, and after drying, it forms a thin layer with weak adhesion to the concrete pipe, so the hardened concrete A surface treatment step is required to remove this layer after demolding the tube.

In addition, since the resin of the anti-corrosion layer has a high solidification shrinkage rate,
In the manufacturing process of concrete-based pipes, there is a problem that delamination tends to occur when the concrete hardens on the surface of the concrete, and even after manufacturing, the corrosion-resistant layer has a resin whose thermal expansion coefficient is lower than that of the concrete pipe. Due to its large size, there was a problem in that it was prone to delamination, and it was unable to fully demonstrate its function as a composite pipe in terms of strength and chemical resistance.

In addition, the method for forming the anti-corrosion layer involved manually transporting a container containing the resin, placing it on the inner surface of the concrete layer, and spreading it by centrifugal molding, which required time and effort to transport the resin. It was extremely inefficient.

[Means for solving problems]

The first manufacturing method of a concrete-based composite pipe of the present invention includes a step of centrifugally forming a concrete layer in a formwork, and a bonding layer made of polyester resin on the inner surface of the concrete layer that is not yet hardened. The process consists of a process of centrifugal molding, and a process of centrifugally molding a corrosion-resistant layer of fiber-reinforced plastic by adding resin and fiber during the initial hardening of the resin of the bonding layer, and forming the anti-corrosion layer between the inner surface of the concrete layer and the anti-corrosion layer through the bonding layer. The goal is to create a strong bond between the two.

In addition, the second manufacturing method includes a step of spraying fiber-reinforced plastic on the portions of the formwork where the end surfaces and outer surfaces of the concrete layer are to be covered to form an anti-corrosion layer;
A step of adding concrete during the initial hardening of the resin of the anti-corrosion layer and forming a concrete layer by centrifugal molding, and a step of centrifugally molding a bonding layer made of polyester resin on the inner surface of the concrete layer that is not yet hardened. and a step of centrifugally forming a fiber-reinforced plastic anti-corrosion layer by adding resin and fiber during the initial hardening of the resin of the bonding layer, thereby strengthening the inner surface of the concrete layer and the anti-corrosion layer through the bonding layer. It's about being in close contact.

〔Example〕

Embodiments of the concrete-based composite pipe according to the present invention will be described with reference to the drawings.

First Embodiment A concrete composite pipe A shown in FIG. 1 has a hydrophilic resin (for example,
Corrosion protection of fiber-reinforced plastics (for example, made of glass fiber, carbon fiber, etc. and polyester resin, epoxy resin, vinyl ester resin, etc.) via a bonding layer 2 of polyester resin, epoxy resin, vinyl ester resin, etc. Layer 3 is formed, and between the inner surface of the concrete layer and the anti-corrosion layer, a resin such as a polyester resin having a solidification shrinkage rate larger than that of the concrete layer and smaller than that of the fiber-reinforced plastic is used. intervening bonding layer, which prevents delamination that occurs during the concrete manufacturing process.Also, the thermal expansion coefficient of the bonding layer is larger than that of the concrete layer and smaller than that of fiber-reinforced plastic, so delamination after manufacturing is prevented. Prevented.

Therefore, there is a bonding layer 2 on the inner surface of the concrete layer 1.
However, the anti-corrosion layer 3 adheres firmly to the bonding layer 2, ensuring great rigidity due to the concrete layer 1 and chemical resistance and strength due to the anti-corrosion layer 3.

Second Embodiment The concrete-based composite pipe B shown in FIG. The anti-corrosion layer 3 is formed through the . The anti-corrosion layer 3 formed on the outer circumferential surface of the concrete layer 1 has a higher solidification shrinkage rate than the concrete layer 1, so a tightening force acts on the concrete layer 1, and the interlayer Peeling is unlikely to occur.

Third Embodiment The concrete composite pipe C shown in FIG.
A corrosion protection layer 3 is formed on the inner surface of the concrete layer 1 with a bonding layer 2 interposed therebetween.

Fourth Embodiment The concrete-based composite pipe D shown in FIG. 4 is a pipe having a spout and a socket, and an anti-corrosion layer 3 is formed on the inner surface of the concrete layer 1, the spout and the socket. A corrosion protection layer 3 is formed on the inner surface of the concrete layer 1 with a bonding layer 2 interposed therebetween.

Next, the method for manufacturing a concrete-based composite pipe of the present invention will be explained step by step with reference to the drawings.

Manufacturing method of concrete composite pipe A (a) Forming process of concrete layer 1 As shown in FIGS. The molds 4 and 5 are placed on top of each other, and the power of the motor is transmitted to the drive roller 6 to rotate both formworks 4 and 5.

Concrete is inserted through one opening 5a of the side formwork 5, charged by a belt conveyor 8 movable in the longitudinal direction of the body formwork 4, and compacted to a predetermined uniform thickness by centrifugal forming to form a concrete layer 1. to form.

(b) Forming process of bonding layer 2 As shown in FIG. (The illustration of the driving roller 6 and the driven roller 7 is omitted).
A mixed resin of the hydrophilic resin and a hardening agent is injected through an injection pipe 9 movably inserted in the longitudinal direction of the concrete layer 1, and a bonding layer 2 of a predetermined uniform thickness is formed by centrifugal molding.

At this time, the hydrophilic and fluid resin is
It quickly spreads over the inner surface of the concrete layer 1 due to centrifugal force, and comes into contact with the concrete layer 1 that is not yet hardened, increasing the degree of adhesion.

(c) Forming process of anti-corrosion layer 3 When the resin of the bonding layer 2 is in the initial hardening state (hardened state to the extent that it can be dented with a fingertip), a molding layer was inserted so as to be movable in the longitudinal direction of the bonding layer 2 as shown in FIG. While the resin is introduced through an injection tube, the fibers are introduced through another injection tube, and the anticorrosive layer 3 of fiber-reinforced plastic is formed by centrifugal molding.

At this time, the anticorrosion layer 3 increases the degree of adhesion with the bonding layer 2, and the inner surface of the anticorrosion layer 3 is finished as a smooth surface with a small roughness coefficient by centrifugal molding.

In addition, the thickness of the anticorrosion layer 3 is determined as appropriate depending on the application, such as increasing the thickness when high chemical resistance and strength are required, and the blending ratio of fibers is also determined according to the application. %, and the fiber length is also
The range is 10-50mm.

Manufacturing method of concrete-based composite pipe B The manufacturing method is basically the same as that of composite pipe A, but first the anti-corrosion layer 3 to cover both end faces and both ends of the outer surface of the concrete layer 1 is formed.

That is, as shown in FIG. 7 (the driving and driven rollers 6 and 7 are not shown), annular bodies 10 made of rubber or the like are fitted onto both ends of the body formwork 4, and fiber-reinforced plastic is blown onto the body formwork 4. A corrosion protection layer 3a having a predetermined thickness is formed in advance.

Next, when the resin of the anticorrosion layer 3a is in its initial stage of hardening, the annular body 10 is removed, and similarly to the composite pipe A, the concrete layer 1, the bonding layer 2, and the anticorrosion layer 3 are sequentially centrifugally formed.

The resin of the anti-corrosion layer 3a contracts during hardening and comes into close contact with both end surfaces and both ends of the outer surface of the concrete layer 1.

Manufacturing method for concrete-based composite pipe C As shown in Fig. 8 (driving and driven rollers 6 and 7 are not shown), an annular body 11 made of rubber or the like is attached to the side formwork 5, and a fiber-reinforced plastic The anti-corrosion layer 3b of a predetermined thickness is formed in advance by spraying.

Next, when the resin of the anti-corrosion layer 3b is initially hardened, the annular body 11 is removed, and the anti-corrosion layer 3, the concrete layer 1, the bonding layer 2 and the anti-corrosion layer 3 are sequentially centrifugally formed.

The resin of the anti-corrosion layer 3b and the anti-corrosion layer 3 on the outer surface shrinks during hardening and comes into close contact with both end surfaces and the outer surface of the concrete layer 1.

Manufacturing method of concrete composite pipe D Body formwork 12 and socket side formwork 1 shown in Fig. 9
3. Using the side formwork 14 of the gap (the illustration of the driving and driven rollers 6 and 7 is omitted), each side formwork 13,1
Annular bodies 15, 16, 17, and 18 made of rubber or the like are attached to 4, and anticorrosion layers 3c and 3d of a predetermined thickness are formed in advance by spraying fiber-reinforced plastic.

Next, the concrete layer 1, the bonding layer 2, and the anticorrosion layer 3 are sequentially centrifugally formed.

The resin of the anti-corrosion 3c, 3d shrinks during hardening and adheres closely to the concrete layer 1 of the socket and the spigot.

In addition, the concrete-based composite pipes B, C, and D
In , the reason why the bonding layer 2 was interposed only on the inner surface of the concrete layer 1 was that the resin of the bonding layer 2 was expensive, and the anticorrosion layer 3 on the inner surface of the concrete layer 1 was
Particular emphasis was placed on preventing peeling.

〔effect〕

In the concrete-based composite pipe of the present invention, the bonding layer is formed on the surface of the concrete layer that is not yet hardened, so the bonding layer easily bonds to the surface of the concrete layer, and the bonding layer protects against corrosion during the initial hardening of the resin. Since the layers are molded, the adhesion between the bonding layer and the anti-corrosion layer is high, and the three layers are strongly bonded.

[Brief explanation of drawings]

Figures 1 to 4 show examples of concrete-based composite pipes. Figure 1 is a cross-sectional view of a concrete layer with an anti-corrosion layer formed on the inner surface, and Figure 2 is a cross-sectional view of the inner surface, both end faces, and outer end of the concrete layer. Figure 3 is a cross-sectional view of the concrete layer with the anti-corrosion layer molded on the entire surface of the concrete layer, Figure 4 is a cross-sectional view of the inner surface of the concrete layer, the socket and the spigot with the anti-corrosion layer formed. 5 to 9 show the steps of the method for manufacturing the composite pipe described above, and FIGS. 5A and 5B are explanatory diagrams of the concrete layer forming process of the composite pipe in FIG. 1, and FIG. An X-ray cross-sectional view, FIG. 6 is an explanatory diagram of the process of forming the bonding layer of the composite pipe, and FIG. 7 is an explanatory diagram of the process of forming the anti-corrosion layer on both end surfaces and both ends of the outer surface of the concrete layer of the composite pipe in FIG. 2. Figure 8 is an explanatory diagram of the process of forming anti-corrosion layers on both end faces of the concrete layer of the composite pipe in Figure 3, and Figure 9 is
It is an explanatory view of the process of forming an anticorrosion layer on the socket and spigot of the composite pipe shown in the figure. 1... Concrete layer, 2... Bonding layer, 3...
Corrosion protection layer, 4... Body formwork, 5... Side formwork, 8...
Belt conveyor, 9... Injection pipe, 10, 11, 1
5-18... Annular body.

Claims (1)

[Scope of Claims] 1. A step of centrifugally forming a concrete layer in a formwork, a step of centrifugally forming a bonding layer made of a polyester resin on the inner surface of the concrete layer that is not yet hardened, and the above bonding. This concrete system consists of the steps of centrifugally forming a corrosion-resistant layer of fiber-reinforced plastic by adding resin and fiber during the initial hardening of the resin in the layer, and firmly adhering the inner surface of the concrete layer and the corrosion-resistant layer via a bonding layer. Method for manufacturing composite pipes. 2. A process of spraying fiber-reinforced plastic to the parts of the formwork that should cover the ends and outer surface of the concrete layer to form an anti-corrosion layer, and adding concrete during the initial hardening of the resin of the anti-corrosion layer, and forming the concrete layer by centrifugal molding. A process of centrifugally molding a bonding layer made of polyester resin on the yet-to-harden inner surface of the concrete layer; Adding resin and fibers during the initial hardening of the resin of the bonding layer, A method for manufacturing a concrete-based composite pipe, comprising the steps of centrifugally forming a corrosion-resistant layer of reinforced plastic, and firmly adhering the concrete layer and the corrosion-protective layer via a bonding layer.