JPH027809B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to general use cases such as insulating tanks and steel pipe coating materials for rust prevention and corrosion prevention. The present invention relates to a method for manufacturing a trough-shaped fiber-reinforced cement product with uniform or nearly uniform thickness, which requires high strength in the circumferential direction.

[Conventional technology]

Conventionally, the method for producing the above-mentioned gutter-shaped fiber-reinforced cement products has been to use the above-mentioned fiber-containing cement mortar (hereinafter sometimes referred to as FRC).
over the entire upper surface of the gutter-like formwork with the upper side open.
A known method is to spray up the material to a uniform or nearly uniform thickness, and then use a trowel or roller to perform defoaming and surface finishing.

[Problem to be solved by the invention]

When using the above conventional method, the following problem occurs.

In other words, it is not a big problem if the cement product to be manufactured is not very curved and is close to a flat plate shape, but in order to reduce the number of combinations when creating a cylindrical shape, individual cement products are If the formwork is greatly curved so that both ends of the formwork rise up, both ends of the formwork in the circumferential direction are steeply sloped surfaces, so even if a thick layer of uncured FRC is sprayed, those parts will easily slip off the formwork surface. Therefore, it is difficult to manufacture thick-walled products, or it is necessary to repeat spray-up several times, and degassing and surface finishing are done manually, which reduces production efficiency. was very bad. In addition, because it was done manually, the inner surface could not be finished smoothly and the thickness accuracy was also lacking.

In addition, as the mold is clamped using the flathead or roller, the fibers flow both in the circumferential direction and the axial direction, and the randomly oriented fibers are oriented almost uniformly in the axial and circumferential directions. There is no or very little difference in strength, therefore, when obtaining the required strength for this type of product that requires greater strength in the circumferential direction than in the axial direction, the strength in the circumferential direction that is the maximum required strength. Since the product must be manufactured based on the axial direction, the product is of excessive quality and has a strength higher than the required strength in the axial direction, which tends to increase the manufacturing cost.

In view of these circumstances, the present invention improves and utilizes the well-known pressing method to efficiently produce curved cement products from thin to thick walls with good finish.
Moreover, it is an object of the present invention to provide a method by which a product having a high strength ratio in the circumferential direction can be obtained.

[Means to solve the problem]

The technical means of the present invention developed to achieve the above object includes a gutter-like lower formwork with an open upper side and an upper formwork located opposite to the lower formwork from above. When using the press method, which is conventionally known as a manufacturing method for flat plate products, in which the cement mortar containing reinforcing fibers supplied between the two formworks is clamped, the periphery of the gutter-shaped lower frame is Supply the fiber-mixed cement mortar in an amount equivalent to the entire product at the recessed bottom part corresponding to a part in the direction and almost uniformly over the entire range in the axial direction of the lower formwork, and Since it is characterized by performing the above-mentioned mold clamping from the state, it has the following functions and effects.

[Effect]

(i) Supplying fiber-mixed cement mortar almost uniformly at the bottom of the recess corresponding to a part of the circumferential direction of the gutter-shaped lower formwork and over the entire range in the axial direction of the lower formwork. However, since the mold is clamped between the upper and lower molds, the FRC mainly flows in the circumferential direction as the mold is clamped, and as a result, most of the fibers are oriented in the circumferential direction. be done.

(ii) Moreover, the mold is formed into a predetermined shape by clamping the upper and lower molds, eliminating the need for conventional manual degassing and surface finishing using trowels and rollers.

〔Effect of the invention〕

(a) Due to the effect of (i) above, it is possible to reliably obtain a product with a high circumferential strength ratio, which is required for this type of reinforcing fiber-containing trough-like cement product. Therefore, it is easy to avoid the increase in cost that would be caused by producing an over-quality product with an unnecessarily high axial strength.

(b) Due to the effect of (ii) above, it is possible to eliminate manual labor as much as possible, achieve high efficiency regardless of wall thickness, and achieve a finish with good smoothness on both the inside and outside surfaces, as well as superior thickness accuracy. I was able to obtain the product.

〔Example〕

Examples of the method of the present invention will be listed below in order of steps based on the drawings.

An amount of cement mortar (m) mixed with reinforcing fiber (a) such as glass fiber, carbon fiber, or a mixture of both fibers, equivalent to the entire product, is poured in the circumferential direction of the lower formwork 2, which is curved into a semi-cylindrical shape. The spray 3 is applied to the bottom of the recess corresponding to a portion thereof almost uniformly over the entire range in the axial direction of the lower formwork 2. (See Figure 1) By operating the vibration motor 4 attached to the lower formwork 2 and pressing it against the lower formwork 2 using hydraulic pressure, the FRC is formed into a pair of upper and lower formworks 1 and 2. It is molded into a shape that matches the shape of the space to be formed. (Refer to Figure 2) When the product has a high rising part as in this example, the fluidity of FRC can be improved by adding vibration during pressurization, and the fluidity of the FRC can be improved by applying vibration to the tip of the rising part with a low pressurizing force.
Since the FRC flows in, it is particularly preferable to add vibration to the pressurization.

At this time, since the FRC mainly flows in the circumferential direction, the reinforcing fibers are more oriented in the circumferential direction.

Through the perforated iron plate 1A that forms a substantial pressing area on the upper formwork 1 side and the filter 5 whose mesh does not allow cement particles to pass through, the FRC is hardened to the extent that it can self-retain its shape by the suction action of a vacuum pump (not shown). Vacuum the excess water until it escapes. (See Figure 3) After dewatering is completed, the upper formwork 1 is removed from the mold and the FRC is allowed to harden and cure until it completely loses its fluidity, resulting in a semi-cylindrical fiber-reinforced cement product as shown in Figure 4. get an A.

In addition, the products to be manufactured by the present invention may have a trapezoidal cross-sectional view, for example, as shown in FIG. .

[Brief explanation of drawings]

The drawings show an embodiment of the method for manufacturing fiber-reinforced trough-like cement products by the pressing method according to the present invention, and
3 to 3 are longitudinal sectional views in the manufacturing process, FIG. 4 is a partially cutaway perspective view of the product, and FIG. 5 is a partially cutaway perspective view of the applied product. 1... Upper formwork, 2... Lower formwork, a... Reinforcing fiber, m... Cement mortar, A... Product.

Claims (1)

[Claims] 1. A gutter-shaped lower formwork 2 with an open upper side, and an upper formwork 1 located opposite to the lower formwork 2 from above.
The cement mortar m containing reinforcing fibers A supplied between the two formworks 1 and 2 is clamped with the molds 1 and 2, and the thickness is uniform or almost uniform, and the central part in the circumferential direction is is a method for manufacturing a fiber-reinforced cement product A having a trough-like shape that is curved in one direction in its wall thickness direction, the recessed bottom portion corresponding to a part of the trough-like lower frame 2 in the circumferential direction; Further, the fiber-mixed cement mortar m is supplied in an amount equivalent to the entire product almost uniformly over the entire range in the axial direction of the lower formwork 2, and from this state, the mold clamping is performed as described above. A method for producing a fiber-reinforced trough-like cement product using a pressing method, characterized by: 2. A method for manufacturing a fiber-reinforced trough-shaped cement product by the pressing method according to claim 1, wherein vibration is applied during the mold clamping. 3. A method for manufacturing a fiber-reinforced trough-like cement product by a pressing method according to claim 1 or 2, wherein the target product A is semi-cylindrical.