JP2735164B2 - Reinforcement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention is intended to be embedded in a structural material having a low tensile strength, such as a hydraulic hardened product, a plastic product, etc.
The present invention relates to a reinforcing material used to enhance bending strength.

<Prior art> Conventionally, for this use, reinforcing bars and PC tendons are known.
There are problems such as lack of durability of strength due to rust, expansion cracks due to rust, large specific gravity and heavy weight, and low electric insulation and high magnetic permeability depending on other uses. In order to solve these problems, an organic fiber and an inorganic fiber having high electrical insulation, high magnetic permeability and a low specific gravity without being rusted, and made into a fiber aggregate and made into a rod by resin bonding have been devised. I have.

<Problems to be Solved by the Invention> However, Kevlar fibers, which are organic fibers, have high strength but are expensive, and have poor alkali resistance and have a problem in durability. Glass fibers and carbon fibers, which are inorganic fibers, also have high strength, but the fibers are cut at the time of manufacture of the rod material, resulting in poor workability, and it is very difficult to perform reinforcement. In addition, glass fibers have problems such as low alkali resistance, and carbon fibers are expensive. As described above, none of the requirements for structural reinforcing materials such as high strength, high Young's modulus, alkali resistance, adhesion with cement matrix, etc. are satisfactory, and even while using high-strength fibers, At present, there is no rod that makes full use of its performance. The inventors of the present invention have studied diligently as a result of the study, and have made it possible to provide a high-performance structural reinforcing material sufficiently utilizing fiber properties.

SUMMARY OF THE INVENTION The present invention provides a structural reinforcing material having a large reinforcing effect, which uses a high-strength, high-elasticity polyvinyl alcohol fiber, reduces unevenness in alignment, and makes full use of the original high-strength, high-elasticity performance. .

<Means for Solving the Problems> The fibers used in the present invention must be polyvinyl alcohol fibers. Nothing satisfies all properties such as alkali resistance, adhesiveness to cement, electromagnetic properties, rust resistance, workability, and light weight other than polyvinyl alcohol fiber, and is relatively inexpensive. The present invention has a tensile strength of 14
g / dr or more, Young's modulus is 300 g / dr or more, and polyvinyl alcohol fibers are aggregated lightly between single yarns to make the apparent number 10 to 85% of the total number of constituent single fibers (hereinafter referred to as the number of constituent fibers). It is a reinforcing material that is arranged in the axial direction and is made by bonding the fibers with a binder. Also, the present invention has a
Polyvinyl alcohol fibers having a denier of at least 14 g / dr and a Young's modulus of at least 300 g / dr, and having a denier of at least 6 denier, are arranged in the axial direction, and are reinforced by bonding the fibers with a binder. Material.

First, in order to obtain the intended structural reinforcing material, that is, to obtain the bending strength of the concrete product at an appropriate amount,
The polyvinyl alcohol fiber must have a tensile strength of at least 14 g / dr and a Young's modulus of at least 300 g / dr. If it is less than this, a rod having sufficient strength cannot be obtained, and the reinforcement for concrete is not used. In the fiber aggregate, the drawing effect is reduced as the amount of aggregated fiber is increased. However, the higher the fiber strength and the higher the Young's modulus, the better the alignment. Therefore, in order to secure a high strength utilization rate, one of the important points is how well the alignment is achieved. As a result of various studies, the inventors of the present invention have found that a single aggregate of the yarns in which the apparent number of the single fibers is 10 to 85% of the number of the constituents is used as a raw material so that the impregnating property of the resin is reduced. Found that good alignment can be achieved without impairing the quality. Further, the present inventors have found that the fineness of the constituent single fibers is 6 denier or more, preferably 6 to 40 dr, so that the alignment of the single fibers is good, the resin impregnation is effective and smooth, and the binding force between the single fibers is also high. I also found it to be good.

Poor alignment of the single fibers is caused by frictional resistance at each part of the guide, tensor or roller at the time of joining. In order to solve this, the single fibers are lightly adhered so that the apparent number of fibers becomes 85% or less. Any further variation will have little focusing effect. Conversely, if the bundle is further strengthened and the number is reduced to 10% or less, the impregnation of the aggregated yarn with the resin becomes poor and uneven, and the utilization factor and processability are significantly reduced. The term “glue” as used herein means that a part or all of the single fibers constituting the yarn is adhered, and the adhesive force is weak, and if friction is applied by a guide or the like, the adhesion is broken to become a single fiber. To determine the degree of sticking, cut the yarn to a length of 2 mm, spread it on a black cloth, count the bonded fibers as one, and express the number as a percentage of the number of single fibers constituting the yarn. It is a thing. The method of obtaining the agglutinated polyvinyl alcohol yarn during the manufacturing process is, for example, a method of adjusting the spinning conditions of the polyvinyl alcohol fiber to cause agglutination, and the other is using a sizing agent before drying in the finishing process. In the examples described below, an aqueous solution of 3 to 50 g / polyvinyl alcohol was applied to 1800 dr passing at 200 m / min by a roller touch method before drying, and then wound with a winder after drying. The degree of agglutination was adjusted by changing the concentration. It is important that the apparent number after the agglomeration is 10 to 85%, and the paste used is not particularly limited.

Also, if the fineness of the constituent fibers is small, the stiffness of the fibers is weak,
There are many fibers that do not align even when tension is applied, and fluff, loose yarn, and single thread cutting frequently occur when passing through guides, tensor, and rollers. In addition, the resin impregnating property takes a long time to achieve a wet-out state, which is a desirable form, and there is a problem in uniformity. Obviously, the thicker is the better direction.
Although the exact reason is unknown, the impregnation characteristics and the alignment effect are remarkably improved when the denier is 6 denier or more.
That is, when the denier is 6 denier or more, the aligning effect in each process is improved, the rod strength utilization rate is improved, and the impregnation and uniformity of the binder are also improved, which is advantageous for cost reduction by speeding up production. is there.

In addition, by using polyvinyl alcohol fiber, there is no problem caused by metallic materials such as rust, durability, electromagnetic characteristics, and poor workability due to heavy weight as described above.
Like aramid, carbon, glass, alkali resistant,
Not only does it have no problem in processability, it also has good adhesiveness with the matrix, and is also cost-effective because a versatile polyvinyl alcohol resin is used. Here, although not particularly specified as the binder, an epoxy resin, a urethane acrylate resin, a vinyl ester resin, a polyester resin, or the like can be used. The ratio of binder in the reinforcement is 20-50
% By weight is preferred.

<Effect of the Invention> The bar material prepared as described above sufficiently exhibits the performance of the fiber, has good alkali resistance, and has excellent adhesion to the material to be reinforced,
Not only has a large reinforcing effect, but also has a lightweight rod, good electrical insulation, low magnetic permeability, no rust, high alkali resistance, and a large reinforcing effect. It is also very effective as a reinforcing material for salt-damaged concrete members, mounts for linear motor cars, and the like.

Next, examples of the strength utilization rate and the reinforcing effect of the fiber of the manufactured rod material will be described.

Examples 1, 2 and Comparative Examples 1 to 5 Polyvinyl alcohol fibers having a yarn denier of 1800dr / 1000f were produced during the drying step of the production.
Gluing was performed using an adhesive at a concentration of 15 g /. Using this fiber, the total number of single fibers is gathered to 241200dr, epoxy resin, Yuka Shell Epoxy Co., Ltd. Epicoat 828-100
The mixture was impregnated with a mixed resin of parts by weight and DX126-80 parts by weight and EM1-24-1 part by weight, and was heated and cured at 150 ° C. for 30 minutes to prepare a bar having a diameter of 7 mm. The proportion of resin in the bar is 30
% By weight.

Around the bar, the same polyvinyl alcohol fiber having a yarn denier of 5400dr / 3000f and impregnated with the same resin were spirally wound with a 5 mm pitch to form a deformed bar.

The deformed bar is mixed with the following concrete standard composition (single position kg
/ m ³ ) ... Table 1 A rod-shaped bar specimen as shown in FIG. 1 was prepared, and after curing for 4 weeks in the air, the bending strength was measured by the measuring method as shown in FIG. The results are shown in Table 2. The bending strength shown in FIG. 2 was measured using a Shimadzu universal testing machine at a loading speed of 2 mm / min and a span length of 600 mm.

From the above results, fiber strength is 14 g / dr, Young's modulus is 300 g / dr
The above shows that the use of the lightly agglomerated fiber makes it possible to produce a high-strength FRP bar with little reduction in the utilization factor of strength and to obtain a concrete product having a large reinforcing effect.

Comparative Example 5 uses Kevlar 49 (1500dr / 1000f). Here, alkali resistance refers to a cement extract with a pH of 12.5 at 80 ° C.
× Visual judgment was made with the rod after 6 months of introduction.

Examples 3 and 4, Comparative Examples 6 to 9 The number of fibers was 2412 using polyvinyl alcohol fibers.
00dr, epoxy resin, Yuka Shell Epoxy Co., Ltd. Epicoat 828-100 parts by weight and DX126-80 parts by weight, E
Fibers were impregnated with M1-24-1 part by weight of the mixed resin at 40% by weight with respect to the fiber, and heated and cured at 150 ° C. for 30 minutes to prepare a rod.

Around the bar, the same polyvinyl alcohol fiber having a yarn denier of 5400dr / 3000f and impregnated with the same resin was spirally wound with a 5 mm pitch to form a deformed bar.

The deformed bars were prepared as shown in Fig. 1 using the above-mentioned concrete standard composition to form bar prisms as shown in Fig. 1. After curing for 4 weeks in the air, the bending strength was measured by the measurement method shown in Fig. 2. It was measured.

 Table 3 shows the results.

From the above results, fiber strength is 14 g / dr or more, Young's modulus 300 g
/ dr or more, and if the denier of a single fiber is 6 denier or more, it is possible to manufacture a high-strength FRP bar with little reduction in the utilization of tensile strength and to obtain a concrete product with a large reinforcing effect. ing.

Comparative Example 8 used Kevlar 49 (1500dr / 1000f, aramid). Here, the alkali resistance was determined by visual inspection using rods after being put into a cement extract having a pH of 12.5 at 80 ° C. for 6 months.

[Brief description of the drawings]

FIG. 1 is a front view and a side view of a sample manufactured in the example. FIG. 2 is a front view of the bending strength measuring device for the specimen of FIG.

Claims (2)

(57) [Claims] 1. A tensile strength of 14 g / dr or more and a Young's modulus of 300 g / d.
r or more, the single fibers are stuck together and the apparent number of fibers is
A reinforcing material in which polyvinyl alcohol fibers, which constitute 10 to 85% of the total number of constituent single fibers, are arranged in the axial direction and the fibers are bonded with a binder. 2. A tensile strength of at least 14 g / dr and a Young's modulus of 300 g / d.
r or more, the constituent monofilament denier is more than 6 denier polyvinyl alcohol fibers are arranged in the axial direction,
And a reinforcing material obtained by bonding the fibers with a binder.