JPH10291874A - Polymer impregnated concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a concrete suitably used for applications such as a buried frame mold needing high strength and high durability by using a stretched polypropylene fiber as a reinforcing fiber. SOLUTION: The polymer impregnated concrete uses the stretched polypropylene fiber as the reinforcing fiber. The thickness, length, amount or the like of the fiber to be added to a concrete base material is particularly not limited and can properly be set based on preliminary test or the like. In the polymer impregnated concrete obtained by impregnating a concrete base material with a monomer in which a polymerization catalyst is dissolved, heating and polymerizing the monomer and integrating the produced resin with the concrete base material, the stretched polypropylene fiber is used as the reinforcing fiber for concrete base material. The polymer impregnated concrete is free from the heat deterioration like the conventional vinylon fiber, is free from the generation of rust like steel fiber and is a thin and high strength material even thin in thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer-impregnated concrete which can be used for products such as buried formwork having a small thickness and a high strength.

[0002]

2. Description of the Related Art From the standpoint of durability of concrete structures and labor saving at construction sites, high strength and high durability embedded molds have been developed. Generally, a buried form is used with a thin thickness, and since high bending strength is required, various fibers and resins are used as a reinforcing material. Steel fiber, glass fiber, carbon fiber and vinylon fiber are used as reinforcing materials for fiber reinforced concrete. On the other hand, polymer-impregnated concrete (hereinafter referred to as PIC) reinforced with short fibers is forcibly dried at about 130 ° C during production, so steel fibers and stainless fibers are mainly used, and organic fibers that are weak to heat are deteriorated by heat. Therefore, it has not been put to practical use. For example, vinylon fiber is 120
Burning occurs at ~ 130 ° C. In addition, these organic fibers are
When used as a reinforcing material for ICs and applied to thin plates, impact resistance and fracture toughness are also required.

[0003]

However, there is a problem that the steel fiber deteriorates due to generation of rust, and there is a problem that the stainless steel fiber is expensive and must be handled with care due to burrs.

[0004]

SUMMARY OF THE INVENTION The present invention, which has been proposed in view of the above, relates to a polymer-impregnated concrete comprising drawn polypropylene fibers as reinforcing fibers.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawn polypropylene fiber (hereinafter referred to as OPP fiber) used in the present invention is different from a general polypropylene (PP) admixture, in that PP is drawn at a high magnification. The strength of the fiber alone is about 1.5 times that of the conventional PP admixture, and is excellent in heat resistance. And since it is already provided (marketed) on the market,
It can be easily obtained. In addition, the thickness and length of the fiber,
The amount of addition to the concrete substrate and the like are not particularly limited, and may be appropriately set by a preliminary test or the like. That is, the present invention impregnates a concrete substrate with a monomer in which a polymerization catalyst is dissolved, then polymerizes the monomer by heating, and in a polymer-impregnated concrete in which the produced resin and the concrete substrate are integrated, A polymer-impregnated concrete characterized by using the above-mentioned drawn polypropylene fiber as a reinforcing fiber. Therefore, the structure of the polymer-impregnated concrete of the present invention is not limited at all except for the use of the above-mentioned drawn polypropylene fiber, and any material and structure may be adopted.

The cement used for the concrete substrate used in the present invention includes portland cement, mixed cement, slag cement and the like. The monomer used in the present invention is a substance having a double bond in a molecule and having a property of polymerizing when heated by a polymerization initiator. As a specific example, a vinyl monomer is generally used, but styrene, acrylonitrile, acrylic acid, methacrylic acid esters, and the like may be used, and these monomers may be used alone or in combination. Next, the polymerization initiator used in the present invention is an organic compound having a property of easily breaking a bond by heating to form a radical. As a specific example, it is preferable to use a non-adsorbing polymerization initiator such as azobisisobutyronitrile, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide or the like for a concrete substrate. Peroxides such as benzoyl peroxide, lauryl peroxide, and methyl ethyl ketone peroxide that are adsorbable to concrete can be used in combination with these polymerization initiators. The amount of the polymerization initiator to be used is usually 0.1 to 5% with respect to the monomer, and depends on the polymerization temperature.
It is preferred to use 2%.

In the present invention, a concrete substrate is impregnated with a monomer containing a polymerization initiator. The method is to first harden the concrete enough, then
Dry to absolute dryness with a hot air dryer at 50 ° C., then cool to room temperature. The OPP fiber does not soften or degrade due to heat even in this heating. Next, the concrete substrate is put in a vacuum vessel, and gas components in the concrete substrate are degassed by a vacuum pump. Then, a monomer is injected in such an amount that the concrete substrate in the container in the vacuum state is completely immersed. The monomer covering the concrete base material penetrates the pores of the concrete base material in a vacuum state and is impregnated into the inside of the concrete base material. By heating the monomer in the impregnated concrete substrate, the polymerization initiator contained in advance generates radicals, reacts with the double bond of the monomer to initiate polymerization, and further reacts with another monomer. The polymerization proceeds by the polymerization reaction. Many monomers originally have a boiling point of 150 ° C. or less, and if simply heated in the air, they evaporate and diffuse prior to polymerization, so that the rate of polymerization is small. In order to prevent this evaporation, the present inventors have already invented a method of immersing and polymerizing a concrete substrate impregnated with a monomer in water or a highly viscous liquid, but this method is not used. Suitable for industrial production. The heating temperature of these liquids varies depending on the type of polymerization initiator, but is usually 50 to 80 ° C. in many cases. The reaction time varies depending on the reaction temperature and the type of the polymerization initiator, but is usually several hours. The polymer-impregnated concrete after the completion of the polymerization reaction becomes a product after washing and surface finishing.

[0008] The polymer-impregnated concrete of the present invention thus produced is not limited in its shape or size at all, and can be provided as various secondary products. In the present invention, since the OPP fiber is used as the reinforcing fiber, it has been found that the bending strength and the impact strength are dramatically improved. This is thought to be due to the physical properties of the OPP fiber itself.
It is considered that this is deeply involved in the compatibility with the impregnated polymer. That is, it is considered that the OPP fiber and the polymer have high affinity because they are organic substances, and the OPP fiber improves the strength characteristics and durability of the impregnated polymer portion. In particular, the polymer-impregnated concrete of the present invention does not undergo thermal deterioration like conventional vinylon fibers, and does not generate rust like steel fibers,
Even if it is thin, it becomes a high-strength material, so that it can be suitably used for secondary products such as embedded molds that require high strength and high durability. Further, when used as a buried formwork, the adhesiveness to cast-in-place concrete is excellent.

[0009]

【Example】

(Preparation of Specimens) A total of six specimens were prepared in a 4 × 4 × 16 cm formwork as a test kneading with various kinds of blends and fibers. This was placed at 20 ° C. for 1 hour, and then cured at 60 ° C. for 3 hours. Once the composition of each fiber is determined, 9
Vertical setting was performed using a mold of 00 mm × 450 mm × 12 mm × 6 sheets. This was cut by a diamond cutter in accordance with the test specimen size of various tests, and PIC work was performed. Table 1 shows the raw materials used, and Tables 2 to 6 show the composition and unit price of each specimen.

[0010]

[Table 1]

[0011]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

(Conditions for forming PIC) A monomer (methyl methacrylate) was impregnated and polymerized under a certain condition with respect to various specimens, and a bending test was conducted. The conditions for PIC conversion are shown below. Drying: An operation of placing a test specimen in a drying oven at 120 ° C. for 24 hours to dry it. Degassing: A work in which a test body is placed in a sealed container and a vacuum is applied at 20 mmHg or less for about 1 hour. Impregnation: Injecting monomer and immersing for 1.5 hours. Polymerization: An operation of immersing in water glass at 70 ° C. for 2.5 hours.

(Measurement of Mechanical Properties) Various tests were performed on a concrete-impregnated concrete board according to an embodiment of the present invention obtained by preparing a concrete base material having the composition shown in Table 7 and forming a PIC under the above conditions. The results are shown in Table 8.

[0014]

[Table 7]

[0015]

[Table 8]

Although the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments, and may be implemented in any manner unless the configuration described in the claims is changed. Can be.

[0017]

As described above, the polymer-impregnated concrete of the present invention uses a drawn polypropylene fiber having excellent strength and heat resistance as a reinforcing fiber, so that a product can be manufactured at a lower price than when steel fiber or the like is used. And no rust. The drawn polypropylene fiber improves the bending strength and impact strength of the impregnated polymer portion, and thus can be suitably used for applications such as embedded molds that require high strength and high durability.

Claims (1)

[Claims] 1. A polymer-impregnated concrete comprising drawn polypropylene fibers as reinforcing fibers.