JPS5925757B2 - Improved method for impregnating concrete materials with impregnating agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method of impregnating concrete-based materials with an impregnating agent.

It is widely recognized that concrete-based structures and products have long-term durability.

However, it also has the disadvantage of causing deterioration over time and cracking due to acidic water, hot spring water, seawater, etc.

Furthermore, depending on the location where the concrete material is used, high strength, water impermeability, abrasion resistance, etc. may be required.

In recent years, a new type of concrete type material (so-called polymer-impregnated concrete (hereinafter abbreviated as "PIC")) has been developed, in which molded concrete type materials are impregnated with hoops or resin and then polymerized and hardened to increase strength and corrosion resistance. has been developed and various studies have been conducted.

In this method, the concrete material is generally molded and cured, then demolded and dried, the object to be impregnated is stored in an impregnating tank, the air in the concrete is depressurized and degassed, and the liquid monomer is added to the concrete in this state. After sufficient impregnation is achieved by injecting an impregnating liquid such as or resin and returning it to normal pressure or applying pressure, the excess impregnating liquid is returned to the tank and polymerized and hardened using an appropriate method to form concrete materials and polymers. It is integrated.

Polymerization can be carried out in a product impregnating tank, but it is not preferable if the impregnating liquid is present in plumbing pipes or instruments because it will harden and impede operation or cause malfunctions.

Usually, the material is once discharged and transferred to a polymerization tank where it is heated and polymerized, or it is irradiated with C060-gamma rays for polymerization.

Although this method can produce products with excellent physical properties,
PIC because the cost is several times higher than ordinary concrete.
This is hindering the spread of the product.

The main cost increase factor other than raw material costs is mainly due to depreciation costs due to the large initial investment required for vacuum/pressure impregnation equipment and related equipment.

Therefore, it is important to simplify the device as much as possible to reduce product costs.

Furthermore, in recent research, many applications have been developed that focus on superior corrosion resistance rather than high strength as a characteristic of PIC.

For example, in the northern part of the United States, roads are often frozen in the winter, and salt is sprinkled on them to thaw them, causing significant salt damage.

In particular, when bridge decks corrode, it takes time and money to replace them, so there have been reports of practical research in which polymers are impregnated from the surface of deteriorated or new bridge decks to improve corrosion resistance and abrasion resistance.

One possible way to improve the corrosion resistance of concrete-based materials is to apply paint to the surface of concrete.

However, sufficient protection cannot be expected because the paint deteriorates due to erosion due to pinholes caused by some reason, or peels off due to physical action.

Therefore, it is expected that it will be protected while being integrated with the concrete inside.

The best method is to polymerize and cure by vacuum/pressure impregnation in an impregnation tank.

However, precasting and impregnating large members such as bridge decks not only requires a large amount of cost for the impregnating equipment (
This is difficult in practice.

In the United States, an on-site impregnation device has been developed, but this is just a conventional technique carried out on-site, and the device is not particularly simplified.

Furthermore, with this device, it is impossible to impregnate large marine structures.

Therefore, it has been desired to develop a method that can greatly simplify the impregnation apparatus and operation even if the polymer impregnation effect is reduced to some extent.

The inventors have made extensive efforts to improve these points, and as a result, they have arrived at the present invention.

In other words, metal pipes, plastic pipes, etc. with holes of appropriate size pre-drilled are installed at the time of concrete placement, and after curing, demolding, and drying, monomers or resins are impregnated under pressure and polymerized and hardened. The aim is to improve the physical properties of concrete materials at low cost.

According to the present invention, general small and medium-sized members commercially available as secondary concrete products can be forcedly dried using a hot air circulation dryer or the like.

When integrating polymer and concrete, keeping the structure of the concrete in an absolutely dry state is an important factor in determining the adhesion strength with the polymer.

Therefore, it can be expected to significantly improve the strength and corrosion resistance of small to medium-sized members.

In addition, since it is impossible to keep large members bone dry on site, it is effective for application to reinforced parts with the main purpose of improving corrosion resistance. If possible, the bridge deck can also be constructed on-site.

This method is possible because concrete-based members are generally porous, and the impregnating agent penetrates through the material by pressurizing the material from inside.

Alternatively, a method of impregnating in a natural state without applying pressure may be considered, but the impregnation speed is slow and it is difficult to impregnate the details of the tissue (
Therefore, it is not practical.

Regarding the polymerization method, it can be carried out by heating with heated steam, hot water, high frequency, radiation polymerization, etc. as in the past, but for large members, it is preferable to polymerize at room temperature using a room temperature curing type catalyst-accelerator.

What should be noted with this method is that there is a concern that the pipe holes may become clogged when concrete is poured.

However, even concrete products that have been placed densely are usually impregnated well, so some clogging is almost no problem. This can be prevented by protecting the parts.

The basic equipment required for the present invention is an impregnating agent injection tank, a simple polymerization tank, and a nitrogen gas cylinder.The basic equipment required for the present invention is a small compressor and a dryer. ing.

Here, concrete-based materials include cement concrete, seven-layer mortar, products reinforced with reinforcing bars, steel fibers, wire mesh, etc., structural materials, and inorganic civil engineering and construction materials such as brick molded with clay and gypsum. refers to

EXAMPLES In order to make the present invention clearer, the present invention will be explained by examples.

Example 1 Cement 550ky/m', water 25oky/m'', aggregate 1353kg/m with maximum dimension 5rnrIL, steel fiber 2V
Steel fiber-reinforced concrete mixed with a mixture of o1% and slump 12CrfL was poured into a 15p x 30hCrfL formwork and molded using a vibrator.

In addition, in this formwork, six steel pipes with an outer diameter of 15 mm and a thickness of 2 mm were arranged vertically in a concentric circle with an outer diameter of 10 CrrL, gathered together at the top, and a female thread was cut in the rising part. Make it easy to connect the pipe from the impregnating liquid tank,
Steel pipes with holes of about 5 mm in diameter were inserted at intervals of about 1.5 crrL.

After molding, the mold was removed by steam curing at 65°C for 3 hours.
It was dried at -48 hr.

This concrete was placed in an oil can, a pipe was connected to the impregnating agent inlet, and the impregnating tank was pressurized to 3 kg/- to impregnate the concrete.

The impregnating agent used was 2% azobisbisisobutyronitrile dissolved in methyl methacrylate.

After about 40 minutes, the impregnating agent began to seep into the outer surface of the specimen, so we stopped the injection, covered the injection port with a screw, and heated it to 90°C.
Polymerization was carried out by heating with water vapor for 1 hour.

This specimen showed a compressive strength of 1010 kg/crit and a split tensile strength of 98 kg/i, and the strength of unimpregnated steel fiber reinforced concrete, a compressive strength of 420 kg/=, and a split tensile strength of 40 kg/CI? An intensity value more than twice that of L was obtained.

Example 2 Based on the same idea as Example 1, a pipe for injecting impregnating agent and a steel pipe serving as reinforcing bars were placed inside a 2001 drum, and then 70 mm steel fiber reinforced concrete was poured and heated to 65°C. After -3hr steam curing, 120°G-4
It was dried for 8 hours.

Add the same impregnating agent as in Example 1 to this at 3 kg/crlL-1h.
r Pressure impregnation was carried out, and the drum was capped.

Drill two holes in the lid at symmetrical positions and insert a 90mm hole from one side.
℃ water vapor was introduced, a hose was connected to one of the holes, and the hose was inserted into the water tank for heating and polymerization for 1.5 hours.

The impregnation rate at this time was about 3%. When the drum was cut out and the concrete core was specifically observed, there was a tendency for the bottom corner and the top of the container to be somewhat low, but there was no major impregnation.

As has been specifically described above, the present invention not only greatly simplifies the impregnation plant and reduces the cost of the product, but also makes it possible to easily impregnate objects constructed on site. Its practicality and usefulness are high, as it can be expected to significantly improve physical properties.

Claims (1)

[Claims] 1 Metal pipes, plastic pipes, etc. with holes of appropriate spacing and size are placed in the formwork or at the construction site in advance, concrete material is poured into this, and after molding and curing, an appropriate method is used. A method of impregnating concrete materials with an impregnating agent by pressurizing the material through an embedded pipe.