JPS59122655A - Tension material for prestressed concrete and production thereof and construction using same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention The present invention provides a tendon for prestressed concrete made of fiber-reinforced plastic that has excellent tensile strength, strength, durability, corrosion resistance, and light weight, a method for producing the same, and a prestressed concrete molded product using the tendon as a reinforcing material. It is related to.

Conventionally, steel wire for prestressed concrete has been used as a tension material for prestressed concrete.

Steel rods and stranded wires (hereinafter referred to as PC steel wires, PC steel rods, and PC steel stranded wires) are widely used, but if the concrete covering them is cracked or has uneven parts, corrosion batteries can form. This causes the prestressed concrete structure to corrode and lead to destruction of the prestressed concrete structure.

Especially in the case of tendons for prestressed concrete,
Since high tension is constantly introduced into PC steel materials, so-called
Lighter tendons are required for structural members that are prone to stress corrosion and whose design is influenced by the size of dead loads, such as bridges.

Also, because of its excessive diurnal elasticity, PC steel has the advantage of having a small relaxation value, but has the disadvantage that a small change in the dimensions of the PC steel itself or the PC structural material causes a large change in stress. There is a need for PC tendons that exhibit small stress changes with respect to dimensional changes in the tendons themselves or structural members. From this point of view, it is considered practically preferable that, for example, when a continuous load of 50% of the breaking strength is applied to the tendon, the tensile relaxation value is maintained at about 10 to 20% after two years.

In view of these drawbacks of PC steel, in recent years glass fiber (
Methods have been disclosed for using inorganic long fibers, which are lightweight and have excellent tensile strength, corrosion resistance, and stress relaxation behavior, as tendons for prestressed concrete, such as carbon fibers (including alkali-resistant glass fibers) and carbon fibers. For example, ``a breast-reinforced concrete construction method characterized by using fiber-reinforced plastic rods obtained by impregnating inorganic long fibers with a thermosetting resin, aligning them in the direction of the fibers, and heating and curing the rods as a reinforcing material for concrete'' ( Japanese Patent Application Laid-open No. 50-3416) [
"Breast-stressed concrete construction method" (Japanese Patent Laid-Open Publication No. 3417/1983) characterized in that fiber-reinforced plastic wire reinforced with continuous filaments arranged and bundled in the longitudinal direction is used as a reinforcing material for concrete. It is true that these prior art technologies use long fibers of glass fibers or carbon fibers as tension materials for prestressed concrete, so they are superior in terms of weight reduction and stress relaxation behavior of concrete products, but they have poor corrosion resistance and durability in concrete. Performance cannot be said to be sufficient.

Another problem is that carbon fiber is expensive.

On the other hand, in the present invention, as a result of a detailed study on the characteristics of aromatic polyetheramide fibers, we found that aromatic polyetheramide fibers are significantly superior to glass fibers and carbon fibers in terms of strength, corrosion resistance, hydrolysis resistance, etc. It has the appropriate toughness required for prestressed concrete tendons, and also has excellent stress relaxation behavior. Therefore, when used as a material for prestressed concrete tendons, it is an even better prestressed material. The inventors have discovered that it is possible to provide tendons for concrete, leading to the present invention. That is, the present invention comprises: (1) a core made of an aromatic polyetheramide long fiber bundle;
A tension material for prestressed concrete, characterized in that the sheath portion is a rod-shaped body made of thermosetting resin.

(2) A method for producing a tendon material for prestressed concrete, which comprises splicing a plurality of aromatic polyetheramide long fibers, impregnating them with a thermosetting resin liquid, pultrusion forming them into rod-shaped bodies, and heating and hardening them.

(3) Pre-stressing characterized by splicing a plurality of aromatic polyetheramide long fibers, subjecting them to physical surface treatment, impregnating them with a thermosetting resin liquid, pultruding them into rod-shaped bodies, and heat-curing them. A method for manufacturing tendons for concrete.

(4) The core is an aromatic polyetheramide long fiber bundle,
This is a prestressed concrete structure using a tension material for prestressed concrete whose sheath portion is a rod-shaped body made of thermosetting resin as a reinforcing material.

Here, aromatic polyetheramide fiber is a repeating unit (
1) to (4) R, R.

R4Rs [In the formula, A r(r A r2 t A r3 may be the same or different, and are aromatic carbocyclic residues in which the bonding chains extend in the coaxial direction or in the parallel axis direction, the maximum spacing represents aromatic heterocyclic residues that must be bonded through ring atoms representing , and combinations thereof.

R1-R3 may be the same or different and represent an alkyl group having 5 or less carbon atoms and a hydrogen atom.

A r4 + A r5 may be the same or different,
(selected from paraphenylene group, metaphenylene group)
The relationship between the number of moles of repeating units is substantially tl)
+ +4) = +2), and (1)++24++
31 +t4) = 100 molti, +31
= O to 90 molar ratio, +41 = 50 to 5 molar ratio, preferably (41 = 30 to 10 molar ratio).

Aromatic carbocyclic residues with bonded chains extending in the coaxial direction mean, for example, 1,4-phenylene + 11'-naphthylene, etc. 1, aromatic carbon ring residues with bonded chains extending in the parallel axis direction Examples of ring residues include 1,5-naphthylene, 2,
It means 6-naphthylene, etc.

The aromatic residue is -N=N-, -N=CH-.

They may be bonded to each other by a group selected from the group consisting of -CH=CH- and -C4iiiC-. for example,
Including.

Examples of the alkyl group having 5 or less carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, etc., and a methyl group is preferable.

Ar4+ A r in formula (4) may be the same or different [
selected from moyo<, paraphenylene group, and metaphenylene group.

A substituent may be bonded to the carbon atom of the above aromatic carbocyclic residue and aromatic heterocyclic residue. Such substituents include norogen groups (e.g. chlorine, bromine, fluorine)
, lower alkyl groups (e.g. metal, f-thyl, isopropyl, n-propyl groups), lower alkoxy groups (e.g. methoxy, ethoxy groups), cyano groups, acetyl groups,
A nitro group is removed, preferably a chlorine group and a methyl group.

The aromatic polyetheramide long fibers are used in the form of rovings, yarns, etc.

As the thermosetting resin, epoxy resins and epoxy acrylate resins having alkali resistance are preferable in consideration of strong alkalinity in concrete. Although unsaturated polyester resin is inexpensive, it cannot be said that its corrosion resistance is sufficient. These resin formulations and heat curing conditions may be the same as conventional methods. Further, curing may be thermal curing or room temperature curing using a fast curing agent.

In addition, the volume ratio per cross section of the core (aromatic polyneedleamide long fiber bundle) of the core-sheath type rod-shaped body according to the second invention is 40%.
It is preferable that it is 80 inches. If the tension is less than 40 qb, the strength and rigidity of the tendon will be insufficient, and if it is more than 80 qb, it will be difficult to mold, and the impregnation of the thermosetting resin into the fibers will be insufficient, resulting in insufficient corrosion resistance.

Next, as a method for pultrusion molding into a rod-shaped body, a normal pultrusion molding machine may be used, or pultrusion molding may be performed by hand making using a glass tube or the like. The cross-sectional shape of such rod-shaped tendon material can be obtained by passing it through a die having a predetermined shape, but it can also have a modified cross-section other than circular. Further, for the purpose of improving adhesion to concrete, the surface of the tendon may be subjected to uneven processing or spiral thread cutting.

Furthermore, in order to improve the performance of the tension material against twisting and bending, long fibers of aromatic polyether amide impregnated with resin were wound around the surface of the rod-shaped body by pultrusion in a helical shape or in a crosswinding manner and solidified. It's okay.

Next, the surface treatment is a fiber surface modification treatment for improving the interfacial adhesion between the aromatic polyetheramide long fibers and the thermosetting resin, and physical and chemical treatments are used. Physical treatments include plasma treatment, ultraviolet light treatment, and electron beam treatment.

Corona discharge treatment, etc., and chemical treatment improves the adhesive force between the fiber and the resin interface through an adhesive such as epoxy or incyanate, and the agent itself has a large cohesive force. As expected. Further, the physical treatment and the chemical treatment may be used alone or in combination.

The tension material of the present invention can be used in both the pre-tension method and the post-tension method, but it is more preferable to use the post-tension method.

Unlike PC steel, when used in the boss tension method, there is no need to worry about rust, so unlike the case of PC steel, there is no need to completely cover the surface, simplifying the work of injecting cement grout into the sheath, and eliminating the need for cement grout. It is also possible to do this. As a method for fixing the tension material, it is preferable to use a test suit. The tendon for prestressed concrete of the present invention made of aromatic polyetheramide fiber bundles can be used as an alternative tendon to tendons made of PC steel, glass fiber, or carbon fiber, and can be used to form prestressed concrete structures using conventional methods. However, as a prestressed concrete structure, it has excellent corrosion resistance, durability, corrosion resistance, stress relaxation behavior, etc.

The present invention will be specifically explained below using Examples.

Example 1 Aromatic polyether amide MLa was 1500% obtained by wet spinning a polymer consisting of 25 mol% paraphenylenediamine, 50 mol% terephthalic acid chloride, and 25 mol% 3,4'-diamino-diphenyl ether.
Using 1000 denier filament fibers, 114 filament fibers were combined to obtain a 171,000 denier fiber bundle. The obtained fiber bundle was molded using epoxy acrylate resin (Nippon Yubika, Neopol 82) using a pultrusion molding machine.
The mixture was introduced into a resin bath made by adding 2 g of 50% benzoyl peroxide to 100/l and heated and hardened through a heating die at 100°C to obtain a round bar with a diameter of s mm. The volume ratio of aromatic polyetheramide fiber bundles per cross-sectional area of the rod obtained was 70 cm.

For comparison, as Comparative Example 1, E glass roving was prepared using the same method as Example 1 and had the same diameter as Example 1.
A glass fiber-reinforced plastic round rod having fiber bundles having the same volume ratio was obtained. Example! And comparative examples! The weight ratio per 1 m of the round bar obtained, tensile strength, relaxation value, and strength retention after immersion at 95°C for 200 hours in a cement supernatant liquid made by adding 1 part of Portland cement to 4 parts of 91C water and 9 parts, The appearance measurement results are as shown in the table below. Comparative Example 2 shows the case of a steel wire for prestressed concrete having an outer diameter of 5 Inm.

Claims (4)

[Claims] (1) The core is aromatic polyetheramide length + 4't
, Km bundle, and the sheath part is a rod-shaped body made of 11 ft of thermosetting wood. (2) Tension feathers for presto concrete, characterized in that a plurality of aromatic polyetheramide long fibers are spliced together, impregnated with a thermosetting resin liquid, pultruded into a rod shape, and cured by heating. manufacturing method. (3) A method of doubling a plurality of aromatic polyetheramide long fibers, subjecting them to surface treatment, soaking them in a thermosetting resin solution, pultrusion molding into a rod-shaped body, and heating and curing. A method for producing tendons for prestressed concrete. (4) A prestressed concrete structure using a prestressed concrete tendon as a reinforcing material, which is a rod-shaped body whose core is made of aromatic polyetheramide long fibers and whose sheath is made of a thermosetting resin.