JPH01271580A - Cooling of concrete column - Google Patents

Abstract

PURPOSE:To prevent cracks from being produced caused by thermal stresses due to temperature difference between atmosphere by embedding a pipe extending in the longitudinal direction of a concrete column in the concrete column and supplying a cooling medium through the pipe. CONSTITUTION:A hollow pipe 2 extending in the longitudinal direction of a concrete column 1 is embedded in the column 1. A blower 4 is connected to a branch pipe 3 branched from the bottom of the pipe 2 to the outside of the column. Supplying cooling air via the branch pipe 3 through the pipe 2 by the blower 4, the column concrete is cooled from inside. In cooperation with heat radiation from the outer surface, the column concrete is effectively cooled. As a result, temperature rise due to hydration heat of cement is reduced, cracks caused by thermal stresses due to temperature difference between the atmosphere is prevented, and the decrease in the growth of long-term strength is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for cooling concrete columns in reinforced concrete skyscrapers and the like.

(Prior Art) In a structure in which concrete is poured, such as a reinforced concrete building, the internal temperature rises due to heat generated by hydration of cement.

Normal strength concrete with a design standard strength of about 210 kgf/cd has a relatively small unit cement a of about 300 kg/d, so the temperature rise due to heat generated by hydration of cement is small.

However, the design basis YII! For high-strength concrete with a strength of 420 kgf/c+a or more, the unit cement amount is 450 kgf/c+a.
kg/rrr or more, the temperature rise due to heat generated by hydration of the cement becomes large.

Particularly for members with large cross sections such as columns, the temperature rise is large, reaching 50°C in winter and 80°C or more in summer.

One of the problems with this situation is that the difference between the temperature and the outside temperature is large, which increases the risk of cracking due to temperature stress.

Another problem is that as the concrete temperature increases, the initial strength increases, but the long-term strength growth decreases. When the unit cement IT is 450 kg/rrr or more, this tendency becomes remarkable, and the design standard strength may not be ensured even at the age of 28 to 91 days.

Currently, many high-rise buildings made of reinforced concrete are being planned and constructed, but the above-mentioned problems will have to be solved in the future.

As countermeasures, methods have been proposed to reduce the mixing temperature of concrete by cooling aggregate, using cold water, adding liquid nitrogen, etc., and methods to reduce and delay hydration heat generation by using moderate heat cement, pozzolans, and hardening retarders. has been done.

(Problems to be Solved by the Invention) However, the former method requires a large amount of damage to the concrete mixing equipment, while the latter method increases the material cost and poses problems in terms of its influence on the strength of the concrete itself.

The present invention has been proposed in view of the problems of the prior art, and its purpose is to provide a method for cooling concrete columns that is simple and effective.

(Another Means to Solve the Problem) In order to achieve the above object, the method for cooling concrete columns according to the present invention includes burying pipes extending in the longitudinal direction of the studs in the concrete building, and supplying a cooling medium to the pipes. It is something to do.

(Function) As described above, the present invention has 1. By using a pipe buried in a concrete column so as to extend along the length of the stud, a cooling medium is supplied to the pipe.
This allows the concrete pillar to radiate heat from within, reducing the temperature of the concrete pillar.

(Example) The present invention will be described below with reference to the illustrated embodiments.

(1) is a concrete column, in which a metal hollow pipe (2) extending in the longitudinal direction of the column is buried approximately in the center of its cross section, and a branch pipe branches out from the bottom end of the pipe (2) to the outside of the column. Air blower R (4) is connected to (3).

In the figure, (5) is the column reinforcement, (6) is the beam, and (7) is the slab.

The illustrated embodiment is configured as described above, so that
A blower (4) supplies cooling air to the pipe (2) via the branch pipe (3) to cool the concrete column from the inside, and in combination with heat radiation from the surface, effectively cools the concrete column. It is something.

In the above embodiment, cooling air is used as the cooling medium supplied to the pipe (2), but other cooling gas, cold water, or cooling liquid may be circulated. In this case, the cooling machine, A circulation pump, etc. is also used.

Further, in the above embodiment, a blower (4) is installed in the branch pipe (3).
is connected, but the pipe (2) is connected as shown in Figure 3.
The concrete column may be cooled by connecting an exhaust air a (4') to the end and sucking outside air into the pipe (2) via the branch pipe (3). At this time, like when using a blower,
The exhaust heat from the fan is not blown along with the outside air, allowing the concrete columns to be cooled more effectively. In addition, at this time,
Branch pipes (3) other than the parts to be cooled are closed with lids (8).

Further, the concrete column may be cooled by natural ventilation using a branch pipe (3) provided at the base of the column.

Note that the pipe (2) may be reused as equipment piping at a later date, or may be buried.

In the latter case, the pipe may be filled with mortar, and the air blower R (4) may be removed and used for other purposes.

(Effects of the Invention) According to the present invention, by supplying a cooling medium to the pipe extending in the longitudinal direction of the studs buried inside the concrete building, not only the surface heat dissipation of the concrete column but also cooling from the inside is achieved. It reduces the temperature rise caused by the heat generated by hydration in cement, prevents cracking caused by temperature stress due to the difference in ambient temperature, and prevents a decrease in long-term strength growth.

In addition, the pipes buried in the concrete pillars will be removed at a later date.
It can also be reused as equipment piping.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a longitudinal cross-sectional view showing an embodiment of the cooling method for concrete columns according to the present invention, Fig. 2 is a cross-sectional plan view thereof, and Fig. 3 is a cross-sectional view showing an embodiment of the concrete column cooling method according to the present invention. FIG. (1) Concrete pillar, (2) Hollow pipe,
(3) - Branch pipe, (4) - Blower, (4
) ---One exhaust fan. Agent Patent Attorney Shigeru Okamoto 2nd name, 1st shoulder, 2m, 3rd month, Okamoto ↑

Claims (1)

[Claims] A method for cooling a concrete column, characterized by burying a pipe extending in the longitudinal direction of the column in the concrete column, and supplying a cooling medium to the pipe.