JPS5914426B2 - Curing method for concrete molded bodies - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for curing concrete molded bodies.

Steam curing is known as one of the curing methods for concrete compacts.

This method uses superheated steam to cause dew condensation on the concrete surface, and uses the generated latent heat to heat the concrete from the surface, and internally heats the concrete by creating a temperature gradient between the inside of the concrete and the surface.

Generally, concrete is cured according to a certain schedule, and this schedule includes the pre-curing process,
It includes a temperature raising step, a constant temperature step, and a temperature lowering step.

Among these, each process other than the pre-curing process has the following difficulties.

(1) Since the steam curing method uses the latent heat of superheated air,
It is difficult to uniformly supply heat to the entire surface of the concrete.

Furthermore, concrete has a low thermal conductivity and cannot diffuse heat evenly within it.

(2) For this reason, if excessively high temperature superheated steam is supplied in the temperature raising process, the concrete surface will be locally heated.

As a result, the cement water utilization rate differs between the surface and inside of the concrete, causing so-called swelling and deterioration of quality.

(3) Excessive heat supply is harmful in the constant temperature process to ripen hydration.

That is, in this process, since the concrete self-generates heat, there is no need to supply heat with a high rise rate such as steam, and it is sufficient to simply maintain the concrete at a constant temperature.

However, steam releases a large amount of thermal energy, making temperature control difficult.

(4) In the temperature-lowering process, the steam supply is cut off, but
Sudden changes in heat input create thermal stresses inside the concrete.

Furthermore, since the amount of water evaporation from the concrete surface increases, surface deterioration occurs.

On the other hand, although there are the above-mentioned drawbacks, in the steam curing method, since the input heat is small, the water-use products generally form large crystals, which increases the reaction rate and can provide initial strength, but the final strength is low.

On the other hand, when curing is carried out under a small heat input, the reaction rate is low because the product generally grows slowly and takes a dense form, so initial strength cannot be expected, but the product becomes entangled in a fibrous form. Because they fit together, the final strength is high.

The purpose of the present invention is to solve the above-mentioned drawbacks of steam curing method,
The purpose of this study is to propose a new curing method that combines the advantages of large heat input and small heat input.

To this end, in the present invention, a falling film of hot or cold water is formed in the curing chamber, and the concrete molded body is cured by the water vapor mass transfer and radiant energy generated by this falling film.

This makes it possible to sufficiently increase both the initial strength and the final strength, making it possible to obtain a product of excellent quality.

Hereinafter, the present invention will be described with reference to illustrated embodiments.

In the embodiment shown in FIG. 1, a pipe 2 is arranged at the upper part of an insulated closed curing chamber 1, and hot or cold water is jetted from the pipe wall of the pipe 2 toward the upper part of the inner wall of the curing chamber, so that almost all the walls of the curing chamber are covered with water. A falling film 3 of hot or cold water is formed along the entire surface.

The hot or cold water is collected in a receiver 4 provided at the bottom of the inner wall and discharged to the outside.

The concrete formed body 5 placed in the curing chamber 1 is continuously heated or cooled and cured by mass transfer of water vapor from the falling film 3 and heat radiation between it and the wall of the curing chamber.

That is, in the temperature raising process and the temperature constant process, hot water heated to 30°C to 90°C using solar heat, geothermal heat, or waste water is poured into the pipe 2, and the falling film 3 of the hot water along the inner wall of the curing chamber 1 covers the inner wall of the curing chamber. is heated and heat radiation is generated from its inner wall toward the concrete molded body 5.

In the temperature lowering step, groundwater or surface water at 5° C. to 20° C. is allowed to flow through the piping 2, and its falling film cools the walls of the curing chamber, allowing heat to be radiated from the concrete molded body 5 toward the inner wall.

Note that it is desirable to increase the emissivity by forming a coating mainly containing an oxidizing agent or a coating made of oxide or ceramics on the inner wall surface of the curing chamber.

It is desirable to change the water vapor pressure or radiant temperature in the curing chamber depending on the amount of concrete moldings to be charged.

Therefore, the length of the pipe wall of the pipe 2 through which hot water or cold water is spouted can be increased or decreased by an appropriate control device.

That is, hot water or cold water is spouted over the entire length of the pipe 2 as required, or hot water or cold water is spouted over only half the length of the pipe 2 as the case may be.

Thereby, the area of the inner wall in contact with the falling film 3 is adjusted, and a desired water vapor pressure or radiant temperature can be obtained.

In the embodiment shown in FIG. 2, a heat storage body 6 such as a concrete block is provided along almost the entire inner wall of the curing chamber 1.
A falling film 3 is formed along the surface of the heat storage body 6 by arranging a pipe 2 at the upper part of the heat storage body 6 and a receiver 4 at the bottom thereof.

For example, when solar heat is used as a heat source for hot water flowing into the piping 2, the amount of input heat tends to be excessive in summer, but if the heat storage body 6 is provided as in this embodiment, the excess heat can be absorbed into the heat storage body. It is possible to accumulate only the required amount of heat and radiate only the required amount of heat toward the concrete molded body 5.

Note that the heat storage body 6 may be provided outside the curing chamber 1.

According to the present invention, the heat energy necessary for curing the concrete molded body can be obtained by the falling film 3 formed in the curing chamber 1, so the input heat amount can be controlled very easily.

Therefore, for example, in the temperature raising step, the input heat amount can be set large to develop sufficient initial strength, and in the temperature constant step and the temperature cooling step, the input heat amount can be set small to obtain sufficient final strength.

In addition, in the temperature lowering step, a falling film of cold water may be formed as required to actively cool the molded body.

Such excellent effects can only be achieved by curing by mass transfer of water vapor from the falling film and heat radiation between the surface of the curing chamber in contact with the falling film and the concrete formed body, as in the present invention. becomes possible.

That is, this is because such a strip seal can sufficiently improve the rise characteristics of temperature change when controlling the amount of input heat.

Another advantage of the present invention is that, in particular, a low temperature heat source can be used as the heat source, resulting in energy savings.

As described above, according to the present invention, it is possible to provide a curing device that is economical and has a simple structure and can produce products of excellent quality.

[Brief explanation of drawings]

1 and 2 are diagrams showing embodiments of the present invention. 1...Curing room, 2...Piping, 3...
... Falling film, 4 ... Receptacle, 5 ... Concrete molded body, 6 ... Heat storage body.

Claims (1)

[Claims] 1 Piping is provided along the upper part of the vertical inner surface of the insulated sealed curing chamber, and hot or cold water is jetted from the pipe wall of the piping toward the inner surface of the curing chamber to generate hot or cold water along the inner surface. a temperature raising step of heating the concrete molded body placed for the curing chamber by spouting hot water from the pipe wall of the pipe using a curing device that forms a falling film; a constant temperature step of maintaining the concrete molded body at a constant temperature by ejecting;
The concrete molded body is cooled by cooling the concrete molded body by spouting cold water from the pipe wall of the piping, and the mass transfer of water vapor generated from a falling film of hot water or cold water in each of the above steps and the concrete molded body and the inner surface are performed. A method for curing a concrete molded body, comprising curing the concrete molded body by continuously heating or cooling the concrete molded body by heat radiation generated between the concrete bodies.