JPH04197702A - Method for embedding reinforcing string - Google Patents

Abstract

PURPOSE:To prevent a molded item made of a cement mortal extruded from an extruder under uncured condition from falling down and to attempt to keep the shape by embedding a long fiber or a fine metal wire in the thickness of the wall of the molded item while it is kept under stretched condition over the inside and outside of the extruder. CONSTITUTION:When a cement mortal 1 is extruded from a nozzle 3 of an extruder 2 to obtain a molded item 4, a string-like or a net-like reinforcing string 5 to be embedded continuously in the thickness of the wall of the molded item 4 is wound on a brake drum 6 on this side of the extruder 2 and it passes through the inside of the extruder 2 and moves at the same speed as extrusion speed (a) (the arrow mark) of the molded item 4 from the nozzle 3 and in the same direction while it is stretched by a remarkable tensile force between a stretcher 7 in front of the extrusion side. At the same time, the molded item 4 moves on a belt conveyer 9 moving synchronously with the extrusion speed (a). In this case, as the reinforcing string 5 embedded in the thickness or the wall of the molded item 4, when it is a metal wire, a steel fine wire usually with a diameter of 1.0mm or smaller, a stainless steel fine wire or a twisted wire of these metal fine wires are used.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides continuous reinforcing bars within the wall thickness of a relatively thin and long molded product when cement mortar is extruded using an extruder. Concerning how to deploy effectively.

[Conventional technology 9 Molded products made into plates, cylinders, and other hollow bodies by extruding cement mortar mixed with granular or powdered aggregate and appropriate water using an extruder have already been developed and commercialized. The main methods of reinforcement include mixing organic and inorganic short fibers into cement mortar, or placing relatively thick reinforcing bars or a reinforcing bar network within the wall thickness of a flat or hollow body. This method was the usual reinforcement method used in the past.

[Problem that the invention seeks to solve]

However, this conventional method has the advantage that the wall thickness of the extruded product can be made quite thin when short fibers are mixed in, but on the other hand, the adhesion force between the fibers and cement mortar is small and the fibers The necessary reinforcement cannot be expected because the tensile strength of the material cannot be fully demonstrated. Therefore, as a result, it does not work very effectively in reinforcing the cracking strength of the molded product against external loads, and for the same reason, the toughness value until fracture of the molded product is low, and sometimes it cracks and breaks immediately. be.

The biggest drawback of short fiber reinforcement in extruded products made from cement mortar is that the cement mortar is in an unhardened state when the product is discharged from the extruder. The upright walls on both sides will tend to collapse under the weight of the mortar itself, unless the cement mortar has a considerably high viscosity. However, with a normal extruder, it is extremely difficult to maintain the viscosity of the discharged cement mortar completely constant no matter how much water is adjusted to a constant level. The current situation is that during this period, the product collapses and the incidence of defective products is extremely high. It is no exaggeration to say that the reinforcing effect of short navy blue fibers is exhibited only after the molded product is cured, so it has no ability to retain the shape of the molded product when it is uncured. .

Next, when reinforcing bars are used as reinforcing bars for extruded products, they can be either linear or net-shaped, but in either case, the diameter of the wire used is thick and its own rigidity is large, making it easy to insert into the extruder. By adjusting the reinforcing bar position within the molded product, it is relatively easy to maintain the reinforcing bar position within the molded product, and the fracture value against external loads can be increased to obtain greater toughness. This may cause a problem of corrosion of the reinforcing steel. Normally, there are regulations regarding fogging of reinforcing bars in secondary cement products, and even with a fairly good manufacturing method, the minimum amount of fog on one side is 15%.
millimeters, and the wall thickness will naturally be 30 mm or more. Therefore, from this point of view as well, there are major restrictions on the production of thin-walled products using reinforcing bars.

In order to reinforce extruded products, the present invention does not use short fibers or thick reinforcing bars, but instead uses continuous long fibers or thin metal wires processed into linear or net shapes. By holding the extruder in a tensioned state and embedding it within the wall thickness of the molded product, the soft and pliable reinforcing material can act as if it were a material with great rigidity, allowing the extruder to remain in an uncured state. It prevents the cement mortar molded product discharged from collapsing and retains its shape, and also maintains the buried position at a specified position inside and outside the wall.Furthermore, when using fibers, it firmly adheres to the cement mortar matrix. In order to tighten the fibers, the fibers are impregnated with a curable fluid to increase their adhesion, and their overall effect makes reinforcement even more effective.As a result, the purpose is to obtain long, high-strength molded products with thinner walls. It was done for.

[Means to solve the problem]

The means of the present invention, which was made to solve the various problems of the prior art as described above, will be explained with reference to FIG. 1 and subsequent figures.

FIG. 1 shows a cross-section or a flat plate as an example; of course, other cross-sectional shapes are also possible, but first, cement mortar 1 is discharged from the discharge port 3 of the extruder 2 to obtain the molded product 4. FIG. 2 is a longitudinal cross-sectional view of the main body and front and rear devices of the extruder 2 at the time of the present invention. A linear or mesh reinforcing bar 5 that is continuously embedded within the wall thickness of the molded product 4 is wound around a brake drum 6 in front of the extruder 2, and passes through the inside of the extruder 2 to the discharge side. The molded product 4 is stretched with a considerable tensile force between it and the tension machine 7 in front.
The discharge speed a (arrow) from the discharge port 3 is equal to and moves in the same direction. In the figure, the molded product 4 is discharged at a speed a
It is designed to move along conveyor belt 9 in sync with Isao. Here, if the reinforcing bar 5 buried within the wall thickness of the molded product 4 is a metal wire, it is usually 1. Steel wires, stainless steel wires, or strands of these metal wires with diameters of Omi IJ or smaller are used, as well as continuous long fibers of inorganic fibers such as glass and carbon, and organic fibers such as aramid ζ calamilon.

In FIG. 1, the reinforcing bar 5 is shown as a cross-sectional view, so it appears to be a single wire, but even if it is processed into a net shape using the metal wire or fibers mentioned above; In the case of a single wire, the penetration hole 8 through which the single wire penetrates into the extruder 2 is simply created by opening a small hole through which the single wire of the reinforcing bar 5 can somehow penetrate, and the cement mortar in the extruder passes through the reinforcing bar 5. Since it is drawn into the extruder as it moves, it will not leak from the penetration hole 8 or the la mortar. -However, if the reinforcing bar 5 is in the form of a net, instead of the penetration holes 8 in FIG. 1, as shown in FIG. It is preferable to install a large check valve part 15) attached to the penetration hole side of the extruder 2 and prevent backflow of the cement mortar 1 at the part through which the reinforcing bars 5 of the net-like body pass. The winding speed of the reinforcing bars of the tensile machine 7 is equal to the discharge speed a (arrow) of the molded product 4, and an electrically operated speed synchronizer is usually used. Furthermore, if the braking torque of the brake drum 6 is made adjustable, the tension of the reinforcing bars 5 can be adjusted, and as shown in FIG. It also has the effect of retaining its shape by preventing it from collapsing when it is not yet cured.

In Fig. 1, both the tensioning machine 7 and the brake drum 6 are cylindrical winding types, or the tensioning machine 7 uses a hydraulic piston type, and the torque adjustment of the brake tram 6 uses a mechanical or electric type. There are various methods for maintaining tension and synchronizing the ejection speed, so the choice is free. Furthermore, it is not necessary that the tension of the reinforcing bars in the molded product is all the same; it is natural that the reinforcing bars in the molded product have different strengths and weaknesses, and some reinforcing bars may not be tensioned at times. Furthermore, even if short fibers are mixed in addition to the presence of reinforcing bars 5, the effects of the present invention will not be diminished.

Next, regarding claim 2, it is a vertical cross-sectional view of the interior of the extruder 2 shown in FIG. 2 as an example. The reinforcing bar 5 in Fig. 2 is the extruder 2.
It is designed to reach the discharge port 3 through a positioning jig 10 provided inside the extruder 2, and the jig 10 is connected to the penetration hole 8 of the extruder 2.
One or more can be attached between the discharge port 3 and the discharge port 3. Various shapes can be considered, such as a table-like shape as shown in the jig 10 in FIG. It is sufficient if it is buried in the position. However, in addition to these jigs 10, an adjustment plate is installed near the cement mortar discharge port 3 of the conventional extruder to control the flow of mortar in order to adjust the discharge state of the mortar. It is advantageous to use a device or method for ejecting high-density mortar by narrowing the cross-sectional area of the passage of the first condyle cement mortar as the process progresses to the present invention.

Further, FIG. 3 is a longitudinal sectional view for explaining claim 3.

In this figure, the reinforcing bar 5 is located between the brake drum 6 on which the reinforcing bar 5 is wound and the penetration hole 8 of the extruder 2, and the reinforcing bar 5 is placed before entering the penetration hole 8, and the hardening fluid is put into the container 11 by the guide roller 13. The fibers are impregnated with the liquid inside the body 12 and sent into the extruder 2. This is because in the case of fibrous materials, the cement mortar 1 in the extruder 2 usually has a high viscosity, so this mortar adheres to the surface of the fibers, but does not impregnate them. (The presence of loose fibers within the wall of the molded product causes a significant decrease in the reinforcing effect. However, the curable fluid]
If impregnated with 2, the fibers themselves will harden within the wall of the molded product, and the adhesion force with the cement mortar of the matrix will increase, further increasing its reinforcing effect. Another use is to cure the impregnated curable fluid to impart greater stiffness to the fibers before use. In this case, since the fibers already have high rigidity, they can be used in the same way as the case of reinforcing bars with large wire diameters mentioned above, but in this case as well, the surface of the fibers is usually It is preferable to use the curable fluid 12 after applying the curable fluid 12 thereon. The curable fluid 12 may be a cement slurry alone or a liquid resin such as an epoxy resin, urethane resin, acrylic resin, or unsaturated bonoester resin. In the case of emulsion, epoxy and acrylic resin emulsion are used. It is also used as a mortar mixture of cement and resin.

[Action and effect]

As an effect of the present invention, the strength of an extrusion molded product according to the present invention and a molded product made by a conventional method were compared.

The cement mortar in both cases uses cement and powder aggregate mixed in equal amounts and in the same ratio of water, and the shapes of both the inventive one and the conventional one containing short fibers are 40 mm wide and 1 mm thick.
2 mm long and 160 mm long, and the conventional product reinforced with reinforcing steel has a width and thickness of 40 mm and a length of 160 mm IJ. In addition, in the molded product of the present invention, five alkali-resistant glass rovings of Tex No. 2400 were placed on the bottom surface of a 40 mm wide section in a straight line of 1.0 cm by applying tension at approximately equal intervals. Furthermore, in the case of the conventional method in which short fibers were mixed, 5 mm long aramid fibers were added at 1% based on the amount of cement. Conventional reinforcing steel has a length of 155 mm and a diameter of 2.3 mm.
Two mm-thick reinforcing bars were buried approximately in the middle of the thickness.

For the load test, use an Inkutron tester, place the test piece in the length direction on fulcrums with an interval of 40 mm, apply a pressure blade from the upper center of the test piece, apply a load to it, and calculate the initial value from the load value and deflection curve. The displacement point of the line was taken as the load value at which cracks occurred in the test piece, and the bending strength was calculated from this value. Table 1 shows a set of three test pieces and their average values.

Table 1 Note 1) Crack load Kg Note 2) Bending strength K g / Crn '1st
From the results shown in the table, it can be fully understood that the long fibers of the present invention have a superior reinforcing effect against cracks compared to conventional short fiber reinforcement or reinforcing steel bars.

Next, consider the shape retention capacity of an extruded product with a mouth shape, external dimensions, side height 125 mm, bottom width 150 mm, and side wall thickness of 7 mm at the top and 9 mm at the bottom. We decided to use the same cement mortar composition as in the cracking test to determine the difference between the present invention and the conventional method using short fibers. In the case of the present invention, four glass row rovings serving as reinforcing bars 5 were formed at approximately 1 cm intervals from the upper part of the upright wall 16 on one side, and a total of eight rovings were kept under tension on both sides and formed into a discharge port shape. The situation is shown in FIG. 5, where the taut glass rovings of the reinforcing bars 5 of the invention represent only one tree each on the top of the upright walls 16 on either side. , is a sketch of the discharge side omitting all the reinforcing bars 5 and the tensioning machine 7 in other places.In addition, in the case of the conventional method using short fibers, it is the same as Fig. 6 except for the tensed glass rope and the crimping. Extrude with shape and dimensions,
In both cases, the molded product 4 was moved by a belt conveyor 9 that moved at the same direction speed as the discharge speed a.

As a result of extrusion molding, in the case of the present invention, reinforcing bars 5 shown in FIG.
No deformation or abnormality occurred in the upright walls 16 on both sides due to the tensile force of the tense glass roving, and when the extrusion distance was 1 meter, the extrusion operation was stopped and subsequent changes were observed, but after about 5 minutes. However, no abnormalities occurred, and it was found that it was possible not only to mold thin-walled, high-strength products, but also to mold thin-walled long products that were considerably long in the extrusion direction.

Next, as shown in the sketch of Fig. 6, when a molded product made by mixing short fibers according to the conventional method is extruded from the discharge port 3 of the extruder 2 and reaches a distance of about 20 to 50 cm, its own weight increases. Due to the slight vibration caused by the movement of the sheath molded product, the middle portions of the upright walls 16 on both sides begin to bend slightly, and then the upper edges thereof bend left and right, and the upright walls 16 rapidly collapse, forming a bent wall 16A. The item instantly lost its shape.

The various experiments described above have shown that the type of reinforcing bars, embedding method and positioning within the wall thickness in the cement mortar extrusion molded product according to the present invention has a great effect not only on the strength of the product but also on maintaining the shape and dimensions. It turns out it's crazy.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing a cement mortar extruder according to the present invention and a tensioning device for reinforcing bars before and after the extruder, and FIG.
FIG. 3 is a longitudinal sectional view for explaining claims 2 and 3 of the present invention, respectively. FIG. 4 shows a partial front view and a cross-sectional view of the penetrating plate in the case where the reinforcing bar is in the form of a mesh. FIG. 5 is a sketch of the discharge side of a molded product discharged from an extruder in which reinforcing bars in a tensioned state according to the present invention are embedded. FIG. 6 is a sketch showing the state of the discharge side of the discharge molded product in the case of reinforcing short fibers by the conventional method. 1. Cement mortar 2. Extruder 3 Discharge port 4 Molded product 5 Reinforcement bar 6 Brake drum 7 Tension machine 81 Penetration hole 9 Held conveyor 10 10A, jig a Discharge speed (arrow piece 11 Container

Claims (1)

[Claims] 1) When cement mortar is extruded using an extruder, in order to arrange continuous linear or mesh reinforcing bars within the wall thickness of the molded product, the reinforcing bars are placed inside and outside the extruder. 1. A method for embedding reinforcing bars in an extrusion molded product, the method comprising maintaining the reinforcing bars in an extrusion molded product under tension and moving the cement mortar at a speed equal to and in the same direction as the discharge port of an extruder. 2) In the statement of claim 1, one or more jigs for positioning the reinforcing bars are installed in the extruder, so that the reinforcing bars are properly embedded at predetermined positions within the wall of the molded product. This is a method of burying reinforcing bars. 3) In the statement of claim 1, the reinforcing bars embedded within the wall thickness of the molded product are organic or inorganic continuous linear or network fibers, and in some cases, the fibers are inserted into an extruder. A method for embedding reinforcing bars in which the fibers are impregnated with a hardening fluid beforehand.