JPH07243259A - Method of and device for curing concrete - Google Patents

Abstract

PURPOSE:To prevent concrete from clacking due to variation in the temperature thereof. CONSTITUTION:In a concrete curing device 5 in which a plurality of sheaths 3 set in a form 23 are connected thereto with a heating and cooling unit 5a, cold air FL-A, FL-B is fed to holes 2s in the sheaths 3 so as to cool concrete 20 placed in the form 23 during a period in which the temperature of the concretes rises up due to its cement hydration heat. Further, when the temperature T of the concrete rises up to a maximum temperature TPL, warm air WL-A, WL-B heated by a heater 8 is led through the holes 2S so as to heat up the concrete 20. Accordingly, the concrete 20 is cured while the temperature thereof is adjusted so that the temperature lowering rate DELTAV/D is lower than a predetermined value VX, thereby it is possible to prevent the temperature from abruptly changing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete curing method and a concrete curing apparatus suitable for use in preventing temperature cracking of mass concrete.

[0002]

2. Description of the Related Art Conventionally, when concrete is poured and constructed,
It is known that the heat of reaction hydration of cement raises the temperature of the core of the concrete skeleton, which causes a tensile force inside the concrete skeleton, which may cause so-called temperature cracking. In addition, even after the initial stage of the cement hydration reaction has converged and the concrete skeleton has reached the maximum temperature, if the temperature of the concrete skeleton rapidly drops from its surroundings, cracking may occur due to the rapid temperature drop. It is known that there is a risk that the hair may crack or the hair crack may spread. That is, the concrete skeleton is prone to cracks due to temperature changes, and this tendency is particularly remarkable in mass concrete. Therefore, in order to prevent such temperature cracks caused by the temperature rise due to the cement hydration reaction, a sheath is embedded inside the concrete skeleton, and cooling water is circulated in the sheath after placing the concrete. Therefore, a method of cooling the inside of the concrete frame is known.

[0003]

However, such concrete cooling can simply prevent the temperature rise of the concrete skeleton by coping with the heat of the cement hydration reaction, so if the cooling work is continued forever, There is an inconvenience that the above-mentioned rapid temperature drop is promoted during the curing of the concrete, which in turn causes cracking. Therefore, usually, about 3 days after the concrete is placed, such cooling is stopped, but if the cooling is performed too much,
The rapid drop in concrete temperature cannot be avoided. Therefore, even if such cooling is performed, if concrete curing can be performed in a form in which the temperature change state is always adjusted so that the temperature of the concrete does not drop rapidly after the cooling is stopped, if the concrete is liable to be cracked, Very useful for curing. Therefore, in view of the above circumstances, the present invention accurately adjusts the temperature change state inside the skeleton during concrete curing to prevent cracking due to temperature change of the concrete, a concrete curing method and concrete curing used for this method. A device is provided.

[0004]

Means for Solving the Problems That is, according to the present invention, when the skeleton (22) is made of concrete (20), the temperature of the cast concrete (20) rises due to the heat of cement hydration. While the concrete (20) is cooled, the concrete (2
0) reaches the maximum temperature (TPL), the concrete (20) is heated to change the temperature (T) of the concrete (20) to the maximum temperature (TPL) of the cast concrete (20). ) The temperature decrease rate (ΔT / D) thereafter is adjusted so as to be equal to or lower than a predetermined value (VX). In addition, in the concrete curing method according to the present invention, the cooling and heating of the concrete (20) are performed by gas (FL-A, FL-B), (WL-A, WL).
-B). Further, the concrete curing apparatus (5) of the present invention has a casing (9), and the casing (9) has a plurality of ports (9).
1) is provided so that the inside and outside of the casing (9) communicate with each other,
A cooling medium supply means (6) and a heating medium supply means (6, 8) are connected to the casing (9), and a form (23) is also provided.
A plurality of hollow space forming members (3) are provided therein, and each of the plurality of space forming members (3) and each of the plurality of openings (91) of the casing (9) are connected via a pipe member (10). Connected and configured. Further, in the concrete curing apparatus (5), the heating medium supply means (6, 8) comprises the cooling medium supply means (6) and a heater connected to the cooling medium supply means (6). , Composed. The numbers in parentheses () indicate the corresponding elements in the drawings for convenience, and therefore the present description is not limited to the description in the drawings. The same applies to the following action columns.

[0005]

According to the present invention, the concrete (20) according to the present invention does not violently increase its temperature due to the heat of cement hydration in the initial stage after the casting, and the concrete (20) rapidly reaches the maximum temperature (TPL). It acts so as to be cured in a temperature-controlled state without lowering. Further, when performing concrete curing according to the present invention, concrete (2
It works so that the concrete (20) can be cured without using water for cooling or heating of (0). Further, in the concrete curing device (5) of the present invention, the cooling medium supply means (6) and the heating medium supply means (6, 8) are provided from the respective openings (91) of the casing (9) via the pipe member (10). The cooling medium (FL-A, FL-) in the space forming member (3).
-B) or the heating medium (WL-A, WL-B) can be supplied freely. Further, in the concrete curing apparatus (5) of the present invention, the cooling medium supply means (6) is
It acts so as to function as a part of the heating medium supply means (6, 8) as required.

[0006]

EXAMPLE FIG. 1 is a front view showing an example of a pier under construction of a beam portion using the concrete curing method according to the present invention, FIG.
1 is a side view of the bridge pier shown in FIG. 1, FIG. 3 is a view showing a state where the heating / cooling unit used in the bridge pier construction shown in FIG. 1 is performing cooling curing, and FIG. 4 is a heating curing of the heating / cooling unit shown in FIG. FIG. 5 is a view showing a state of performing
7 is a view taken along the arrow VI in FIG. 3, and FIGS. 7 to 9 are a series of diagrams showing the procedure for performing the concrete curing method according to the present invention.
FIG. 11 is a diagram showing the relationship between the concrete cross section and the concrete temperature during cooling and curing of concrete using the concrete curing apparatus according to the present invention, and FIG. 11 is heating and curing concrete using the concrete curing apparatus according to the present invention. FIG. 12 is a diagram showing the relationship between the concrete cross section and the concrete temperature, and FIG. 12 is a diagram showing an example of the temperature change state of the concrete cured according to the present invention.

As shown in FIG. 1 or 2, the bridge pier 1 under construction has a structural frame 2 made of reinforced concrete, and the structural frame 2 is a leg 2 which is erected and supported on the ground 39.
1 and a beam 22 which is a bridge pier mounted on the leg 21 and is a frame made of concrete 20 to be cured. The leg portion 21 has a rectangular cross section and has already passed a predetermined number of days after the concrete has been cast. The beam 22 has the concrete welded to the upper side of the leg portion 21 so as to be connected thereto. In shape, it is within 3 days after placing concrete. On the bottom surface and the side surface of the beam 22 other than the portion connected to the leg portion 21, the form 23 is formed by molding the beam 22 by the form 23, and the form 23 is not removed yet and is left. The mold 23 is supported by a plurality of temporary columns 25. In addition, a plurality of steps of scaffolding plates 26 are erected on the plurality of columns 25 so as to horizontally connect the adjacent columns 25 to each other. On the plate 26,
Unit installation portions 26a and 26a are provided so as to be located on the right side and the left side in FIG.

As shown in FIG. 1 or 2, the beam 22 is made of a steel pipe, a resin pipe, or the like, and has a hollow portion 3 inside.
A plurality of sheaths 3 which are hollow space forming members in which s is formed are embedded so as to penetrate the beam 22 in the left-right direction of FIG. 1 (the direction intersecting the plane of FIG. 2) which is the longitudinal direction thereof. Each sheath 3 forms a part of a concrete curing device 5 to be described below together with the mold 23 in the form of forming a hole 2s inside the frame of the beam 22 by the hollow portion 3s. That is, as shown in FIG. 1, the bridge pier 1 in the process of constructing the beam 22 is provided with a concrete curing device 5 for performing concrete curing of the beam 22 which is a frame, and the concrete curing device 5 includes the sheath 3 Each hole 2s formed by
In the embodiment, there are two hot and cold units 5a for carrying out curing, that is, cooling curing and heating curing which will be described later.

As shown in FIG. 1, the two heating / cooling units 5a, 5a are temporarily installed in each of the unit installation portions 26a, 26a, and each heating / cooling unit 5a is installed as shown in FIG. 3 or 4. As shown, the propeller fan 6 has a shape in which the blowing direction is different between the cooling curing operation shown in FIG. 3 and the heating curing operation shown in FIG. That is, the propeller fan 6 can be freely blown and driven by selectively directing its blowing direction to either the intake direction shown in the arrow J direction in FIG. 3 or the air feeding direction shown in the arrow K direction in FIG. As shown in FIG. 5, the rear surface of the propeller fan 6 has an opening 6a.
An opening is formed so that the inside and outside of the propeller fan 6 communicate with each other. The opening 6a serves as an exhaust port when the warming / cooling unit 5a is used for cooling and curing as shown in FIG.
When the heating / cooling unit 5a is used for heating and curing as shown in FIG. 4, it serves as an intake port.

Further, as shown in FIG. 3 or 4, on the front side of the heating / cooling unit 5a opposite to the opening 6a of the propeller fan 6, a heater 8 is provided.
The heating wire 8 is connected to the heating wire 8 and is capable of heating the air passing through the inside of the heater 8.
a is stored. The damper 7 is provided on the front side of the heater 8 depending on the angle of the blade portion 7a thereof.
The amount of air blown by the damper 7 is adjustable.
On the front side of the, a distribution box 9 which is a casing formed in the shape of an inner container is detachably arranged in a form connected to the damper 7, the heater 8 and the propeller fan 6 so as to communicate therewith. There is. A seal 12 is provided between the propeller fan 6, the heater 8, the damper 7, and the distribution box 9, and the propeller fan 6, the heater 8, the damper 7, and the distribution box 9 are connected via the seal 12. It has a structure that prevents air leakage, and is removable from each other.

Therefore, in the warming / cooling unit 5a, the propeller fan 6 in a state in which the air blowing direction is directed in the direction of arrow J as shown in FIG. 3 uses the outside air 40 as a cooling medium, that is, the cooling air FL-A. , FL-B, which constitutes a cooling medium supply means for supplying each of the holes 2s of the skeleton 2 to the holes 2s, while the propeller fan 6 is in a state in which the air blowing direction is in the direction of arrow K as shown in FIG. And the heater 8 connected to the propeller fan 6 is connected to the outside air 4 as described later.
0 is supplied to the holes 2s of the skeleton 2 as warm air WL-A and WL-B, which are heating media, and constitutes a heating medium supply means. And these, propeller fan 6
The heater 8 and the heater 8 are provided so as to be connected to the distribution box 9 which is a casing via the damper 7 and the seal 12 as described above.

Inside the distribution box 9, as shown in FIG. 3 or 4, an air circulation space 9s is formed in a substantially columnar shape, and on the front side of the distribution box 9, a predetermined quantity of air is distributed. A plurality of plugs 91 are provided as openings for communicating the inside and outside of the distribution box 9 with each of them protruding to the front side. An opening 91a is formed at the front end of each insertion 91, and the opening 9a of each insertion 91 is formed.
A holding portion 91b is provided in the vicinity of 1a in the form of a bamboo-shaped step. The flexible hose 10 which is a flexible pipe member is inserted into each of the plugs 91.
Of the flexible hose 10 are connected to each other via the holding portion 91b so as to prevent the flexible hose 10 from falling off from the insertion 91, and the flexible hose 10 is formed inside the beam 22 by the sheath 3 as shown in FIG. Mouth 2p which is one end of hole 2s
Connected with. In addition, in the embodiment, for the convenience of the drawings, the insertion 9 provided in the two heating / cooling units 5a is used.
Although the total quantity of 1 does not match the total quantity of the holes 2s, the distribution box 9 provided with a predetermined quantity of the inserts 91 such that the total quantity of the holes 2s and the total quantity of the inserts 91 match at the time of construction work. Is used for the heating / cooling unit 5a.

By the way, in the plurality of holes 2s of the beam 22, as shown in FIG. 1 or 2, the mouth 2p is located on the side of the arrow 2sa in FIG. 1 and on the side of the arrow B in FIG. The holes 2sb are provisionally set so that the holes 2sa and 2sb are alternately arranged in the vertical and horizontal directions as shown in FIG. 2, and the holes 2sa and 2sb are cooled respectively as shown in FIG. The flow directions of the cold air FL-A and FL-B flowing during curing are opposite, and the flow directions of the warm air WL-A and WL-B flowing during heating and curing the holes 2sa and 2sb are opposite to each other. , Are connected to different heating / cooling units 5a. That is, the hole 2sa is connected to the mouth 2p on the right side of FIG.
The heating / cooling unit 5a shown on the right side is connected to each insertion 91, while the hole 2sb is connected to the mouth 2p on the left side in FIG. 1 via the flexible hose 10 and the heating / cooling unit 5a shown on the left side in FIG. Is connected to each plug 91. As shown in FIG. 1, the other end of the mouth 2p of each hole 2s is opened as an open end 2q with the sheath 3 forming the hole 2s opening so that the hole 2s communicates with the outside. Therefore, each hole 2s has an opening 6a of the heating / cooling unit 5a connected to the mouth 2p on one end side via the flexible hose 10 and an opening end 2q on the other end side of the hole 2s. It is in the form of communicating with each other.

Since the bridge pier 1 has the above-mentioned structure, when the bridge pier 1 is constructed, when the leg portion 21 which is the lower portion of the structural skeleton 2 is driven and constructed, the structure skeleton 2 is formed.
The concrete 20 of the beam 22, which is the upper part of the, is placed. That is, when the concrete of the leg portion 21 has hardened, the formwork 23 is moved to the form shown in FIG.
As shown in FIG. 5, the beam 22 is assembled and installed in a shape corresponding to the driving shape of the beam 22. At this time, in the form 23, a predetermined number of sheaths 3 required for concrete curing later are formed so that the hollow portion 3s penetrates in the longitudinal direction of the beam 22 shown in the left-right direction in FIG. Install it. In this way, as shown in FIG.
To place. Then, the beam 22 which is a part of the structural body 2 is formed into a predetermined shape by the hardening of the concrete 20. Then, inside the beam 22, the holes 2s are respectively formed by the hollow portions 3s of the plurality of sheaths 3 so as to extend along the longitudinal direction of the beam 22, and the beam 22 is formed so as to penetrate the beam 22 left and right in FIG. To be done.

By the way, the concrete 20 of the beam 22 is
When no curing is performed after the placing, the temperature of the central portion of the core rises with time due to the heat of hydration due to the cement hydration reaction, as shown by the alternate long and short dash line in FIG. Then, the temperature drops at a rapid rate. The maximum temperature TP of the concrete that is not cooled in this manner is higher than the dangerous temperature T1 at which the beam 22 is significantly temperature-cracked. That is, concrete 2
In the case of 0, the temperature rises due to the heat generated by the cement hydration reaction at the time of hardening, and the tensile force acts inside the member in the form that the member in the process of hardening expands with the temperature rise.
Then, since the beam 22 is in the form of being spliced to the leg portion 21 that has already been cast and cured through the bottom portion thereof,
The tensile force generated during the curing is constrained by the cured legs 21, and the beam 22 is exposed to the risk of thermal cracking. This dangerous temperature that is a standard for the occurrence of temperature cracks is the temperature T1 shown in FIG. Furthermore, the maximum temperature T
A rapid temperature decrease after P causes strain in the member cross section of the beam 22 and causes cracking, or stimulates the growth of hair cracks. In any case, the beam 22 skeleton becomes weak. There is a risk of being connected. Therefore, when concrete is poured as described above and shown in FIG. 7, the temperature T of the concrete 20 of the beam 22 is increased by the cement hydration heat by the concrete curing device 5 as shown by the solid line in FIG. While doing so, the concrete 2
0 is cooled and cured, and the concrete 20 has a maximum temperature TPL.
After reaching the temperature, by heating and curing, the temperature decrease rate ΔT / D of the concrete 20 after the maximum temperature TPL is reached.
The temperature is adjusted so that is less than or equal to the predetermined value VX.

Therefore, first, as shown in FIG. 1, each heating / cooling unit 5a of the concrete curing device 5 is connected to each of the plurality of holes 2s formed in the beam 22, that is, each sheath 3. At this time, the heating / cooling unit 5a shown on the right side of FIG. 1 is in the hole 2sa, and the heating / cooling unit 5a shown on the left side of FIG.
Are connected to the holes 2sb so that their mouths 2p
One end of the flexible hose 10 is connected to the end portion of the sheath 3 forming the, and the other end of the flexible hose 10 is inserted into each insertion 91 of the distribution box 9 to be connected.
In this way, when the sheath 3 of each hole 2s is connected to each insertion 91 of each heating / cooling unit 5a via the flexible hose 10, the opening end 2q of the hole 2s and the opening 6a of each heating / cooling unit 5a are communicated with each other. .

In this state, firstly, while the temperature of the concrete 20 of the beam 22 is rising due to the cement hydration reaction (that is, the initial stage after placing), the concrete 20 is cooled and cured. This includes two hot and cold units 5
a and 5a are respectively driven, and as shown in FIG. 8, the outside air 40 is supplied to each hole 2s from its opening end 2q and the cold air FL.
-Called as a cooling medium in the form of A, FL-B. In addition,
The driving of the heater 8 is stopped during the cooling and curing. Then, while adjusting each damper 7, each propeller fan 6 is driven such that its blowing direction is directed in the direction of arrow J as shown in FIG. Then, the propeller fan 6 is driven to cause the heating / cooling unit 5a to send the air in the hole 2s in the direction of the arrow J as shown in FIG. 3, by supplying the air corresponding to the blowing amount Q of the propeller fan 6 as shown in FIG. The suction is applied to each of the heating / cooling units 5a, 5a (that is, the arrow A direction side or the B direction side in FIG. 1). As a result, in each hole 2s,
As shown in FIG. 8, the outside air 40 is drawn in from each opening end 2q. That is, the outside air 40 corresponding to the blown air amount Q flows through the hole 2sa connected to the heating / cooling unit 5a on the arrow A direction side shown in the right side of FIG. To do. In addition, the outside air 40 corresponding to the blown air amount Q flows as the cool air FL-B in the direction of the arrow B in the hole 2sb connected to the warming / cooling unit 5a on the arrow B direction side shown on the left side of FIG. To do. That is, in each hole 2s, the cold air FL- which is a cooling medium corresponding to the air flow rate Q is supplied.
A and FL-B circulate in the directions of arrows A and B, respectively.

In this way, the cold air FL-A, FL is introduced into the hole 2s.
-When B flows in the direction of arrow A or B, the hole 2
The cold air FL-A, FL-B moving in s absorbs the heat of hydration generated by the concrete 20 due to the hydration reaction of the cement as described above around the hole 2s, and the hydration is performed. The heat is applied to the cold air FL-A, FL-B along the flow direction of arrow A.
Direction or B direction, with the result that the concrete 20 is cooled. That is, a beam shape like the beam 22,
As shown in FIG. 10LINE1, a concrete horizontal frame made of concrete with a certain thickness is
Although the temperature of the middle part becomes high, the hole 2s formed in the body
Then, when the cold air FL-A and FL-B are circulated, as shown in FIG. 10LINE2, the temperature of the body is the lowest at the opening end 2q and rises toward the mouth 2p, while FIG.
The distribution state is always lower than That is, the beam 22
Outside air 40 having a temperature lower than the internal temperature of the body such as
The heat generated by the concrete 20 of the beam 22 is taken as A and FL-B, and the heat is taken from the hole 2s to the heating / cooling unit 5a.
Transport it to.

Therefore, in the beam 22 of the pier 1, as shown in FIG.
As shown in FIG. 5, among the plurality of holes 2s, the cold air FL-A flowing in the direction of arrow A in the hole 2sa, and the cold air FL-B flowing in the direction of arrow B in the holes 2sb alternately arranged with the holes 2sa.
However, the cooling air FL-A, FL-B cools and cures the concrete 20 in the form of removing heat from the concrete 20 of the beam 22 around each hole 2s in the circulation process. Then, the beam 22 is provided with a plurality of holes 2s so that a uniform temperature distribution state is obtained without cooling only one side of both longitudinal end portions of the beam 22.
2 is cooled and cured. Then, the cold air FL-A, FL-B flowing in the respective holes 2s in the direction of the arrow A or the direction of the arrow B and having the increased temperature is discharged from the opening 6a of the propeller fan 6 of each heating / cooling unit 5a. 2s exterior or beam 22
Is emitted to the outside of. In this way, the heat generated by the concrete 20 due to the cement hydration reaction is discharged to the outside of the beam 22.

In this way, the concrete 2 of the beam 22 is
For about 3 days after placing 0, the hole 2
When cooling curing is performed while the heating / cooling unit 5a is connected to the sheath 3 forming s via the flexible hose 10, the concrete temperature T of the beam 22 is increased as shown by the solid line in FIG.
Does not suddenly increase in temperature, gradually reaches a relatively low maximum temperature TPL, and begins to show signs that the temperature starts to decrease. At this time, the maximum temperature TPL is the dangerous temperature T
It is a value that does not reach 1. Therefore, the concrete 20 of the beam 22 does not rise in temperature until the temperature reaches the critical temperature T1 where there is a risk of temperature cracking due to the heat of hydration of the cement generated during the hardening, and the cement 20 is properly cooled and cured. The initial stage of the hydration reaction (ie the initial hardening of the concrete 20) is complete.

Therefore, when the concrete temperature T of the beam 22 reaches the maximum temperature TPL and the temperature starts to decrease, the concrete curing device 5 is used to heat the concrete 20 as shown in FIG. Carry out.
For this purpose, the fan 6 is driven so that the blowing direction thereof is in the direction of arrow K as shown in FIG. 4 while the heater 8 of each heating / cooling unit 5a is operated. Then, the fan 6 takes in the outside air 40 from the opening 6a and sucks it in the direction of arrow K. Then, the sucked outside air 40 is heated by the hot wire 8a of the heater 8 in operation. The heated outside air 40 is sent as a heating medium in the form of warm air WL-A, WL-B into the air circulation space 9s in the distribution box 9 by the blowing operation of the fan 6, and is distributed to each insertion 91. Then, each flexible hose 10 is supplied from each opening 91a. (Note that the warm air WL-A is the warm air flowing in the direction of arrow A in FIG.
B is warm air flowing in the direction of arrow B in FIG. ) Then, in the hole 2s connected to the flexible hose 10,
As shown in FIG. 9, the warm air WL-A and the warm air WL-B flows from the respective mouths 2p toward the opening end 2q.

That is, in FIG. 1, in the hole 2sa whose mouth 2p is on the right side of FIG. 1 (the end portion in the direction of arrow A), the warm air WL-
B flows in the direction of arrow B, and at the hole 2sb where the mouth 2p is on the left side of FIG.
-A becomes a shape that flows in the direction of arrow A. Thus
When the heated warm air WL-A, WL-B respectively flows into each hole 2s, the warm air WL-A, WL-B passes through the sheath 3 forming each hole 2s, and of the beam 22 around it. The concrete 20 will be heated. But at this time,
As described above, the temperature of the concrete 20 has already started to decrease as the progress process of the cement hydration reaction. As a result, the temperature of the concrete 20 of the beam 22 heated by the warm air WL-A, WL-B is gradually decreased as shown by the solid line in FIG. 12, ΔT / D (≦ predetermined value VX).
The temperature of the concrete 20 can be adjusted so that the temperature of the concrete 20 decreases. As a result, FIG.
Since a rapid temperature change as shown by the one-dot chain line is prevented, the cause of cracking does not occur.

By the way, when the warm air WL-A, WL-B is circulated through the beam 22 which is the skeleton of the concrete 20 as described above, the beam 22 has the highest mouth 2p and the open end as shown in FIG. 11LINE3. The temperature is adjusted so as to exhibit a temperature distribution state of descending toward 2q. However, in the beam 22 of the pier 1, as shown in FIG. 9, the warm air WL-B is indicated by the arrow B in the hole 2sa among the plurality of holes 2s.
Holes 2s that flow in the same direction and are arranged alternately with the holes 2sa
In b, warm air WL-A flows in the direction of arrow A, and each hole 2
The concrete 20 of the beam 22 around the s is heated. Then, the temperature of the concrete of the beam 22 decreases so that the temperature of only one side of the longitudinal ends of the beam 22 does not become too high and the beam 22 has a uniform temperature distribution. Adjusted.

As described above, the concrete curing device 5 causes the cold air FL-A, FL-B to flow from the heating / cooling unit 5a.
By selectively supplying the warm air FL-A and FL-B to the hole 2s, the concrete temperature T of the beam 22 around the hole 2s becomes the critical temperature T as shown by the solid line in FIG.
Cement hydration reaction proceeds while the temperature does not rise to 1 and always changes gradually.
Is always hardened in a form in which the concrete 20 is always cracked-prevented so that a sudden temperature change does not occur. As a result, the beam 22 appropriately expresses the final strength and exhibits a robust structural state. In this way, each heating / cooling unit 5 of the concrete curing device 5 for curing the concrete 20 of the beam 22.
Since a uses the propeller fan 6 as a cooling medium supply means when there is any, and uses the propeller fan 6 and the heater 8 as heating medium supply means, the structure is simple and the apparatus can be small. Further, each of the heating / cooling units 5a can selectively cool or heat the concrete 20 of the beam 22 in accordance with the changing state of the concrete temperature T of the beam 22, so that a crack is induced by a rapid temperature change caused by excessive cooling. There is no danger. In addition, even if a fine hair crack occurs, there is no risk of growing it to form a complete crack.

In the embodiment, the cooling medium and the heating medium are cold air FL-A, which is a gas using the outside air 40,
Since it is FL-B or warm air WL-A, WL-B, cooling water does not pass through the hole 2s. Therefore, a large-scale facility for cooling water and circulating the cooled water is not required as in the case where cracking is prevented by a water-cooled concrete cooling method. As a result, the equipment required for curing installed on the scaffold is lightweight and small,
Work can be performed smoothly even in a small space such as the unit installation portion 26a. Further, there is no risk that the weight of the beam 22 applied to the support column 25 increases. Furthermore, since the work of collecting water from each hole 2s is not required after the curing is completed, the labor for the water collecting work is unnecessary. Also, by any chance,
Even if the sheath 3 is damaged, water does not pass through the hole 2s, so there is no risk that water will flow from the damaged portion of the sheath 3 to the reinforcing bar of the beam 22 and rust. However, the cooling medium and the heating medium for performing concrete curing by adjusting the temperature of the concrete 20 of the beam 22 do not necessarily have to be the gas using the outside air 40, and other gas may be used. Furthermore, cold water or hot water is used to cool and heat the concrete 20,
Alternatively, such liquid may be passed through the hole 2s in a form of being sprayed in the form of vapor.

In the embodiment, the example in which the frame for which cracking is to be prevented is the beam 22 of the pier 1, but the application of the present invention is not limited to such pier beams. Therefore, as long as the frame body to prevent cracking is made of concrete 20, any frame body having a shape other than that described in the embodiment and constructed for other purposes may be used. Further, in the embodiment, the example in which the sheath 3 is used so that the holes 2s are oriented in a substantially horizontal direction has been described, but such holes 2s for cooling or heating and curing the concrete 20 are provided in the frame made of concrete. It may be formed and arranged so as to extend in the vertical direction inside. Of course, they may intersect with each other or the hole 2s may be bent. Further, the directions and combinations of the cold air FL-A, FL-B and the warm air WL-A, WL-B flowing through the plurality of holes 2s are not limited to the forward and reverse directions as described in the embodiment. Instead, it may be oriented in any other direction. Further, in the embodiment, the sheath 3 used for forming the hole inside the body is left buried inside the body, but the space forming member such as the sheath 3 is separated from the outer periphery of the mold. Apply the agent,
It may be removed after the holes are formed. Further, in order to perform the concrete curing method according to the present invention,
It is not always necessary to use the concrete curing device 5. Therefore, the temperature adjustment of the concrete 20 does not necessarily have to be performed by cooling or heating the hole 2s formed by the sheath 3.

Further, in the embodiment, the propeller fan 6 provided in each heating / cooling unit 5a of the concrete curing device 5 constitutes a cooling medium supplying means, while the propeller fan 6 and the heater 8 constitute the heating medium supplying means. However, the configuration of the cooling medium supply means and the heating medium supply means is not limited to this, and therefore,
The fan 6 does not always function as both the cooling medium supply unit and the heating medium supply unit. Further, in the embodiment, an example in which the distribution box 9 provided with a plurality of insertions 91 is used as a casing provided with a mouth is described, but the configuration of the casing and the mouth provided therein is other than this. May be. Further, the pipe member for connecting the sheath 3 and the insertion 91 need not necessarily be the flexible hose 10, and may be another pipe member, and the space forming member such as the sheath 3 and the insertion 91.
The connection state of the mouths, etc. is not limited to those described in the embodiments, but is arbitrary. Furthermore, the shape and material of the space forming member such as the sheath 3 and the shape and material of the damper 7 and other constituent members of the concrete curing apparatus are arbitrary.

[0028]

As described above, according to the present invention,
When the construction of the beam body 22 made of concrete 20 is carried out, while the temperature of the cast concrete 20 is rising due to the heat of cement hydration, the concrete 20 is cooled, and the temperature rising concrete 20 is the maximum. After reaching the temperature TPL, the concrete 20 is heated, and the temperature T of the concrete 20 is reduced so that the temperature decrease rate ΔT / D of the cast concrete 20 after the maximum temperature TPL is a predetermined value VX or less. Since the concrete 20 does not violently increase in temperature due to the heat of cement hydration in the initial stage after placing, and the concrete 20 reaches the maximum temperature TPL and then rapidly decreases in temperature afterwards. Instead, it is cured in a temperature-controlled state. Therefore, if concrete curing is performed according to the present invention,
It is possible to prevent the temperature rise due to the heat of cement hydration immediately after placing the concrete and prevent the cracks caused by the temperature rise, as well as the inside of the concrete frame after the concrete reaches the maximum temperature TPL. It is also possible to prevent the rapid decrease in the temperature, and prevent cracks caused by the rapid decrease in the temperature. Therefore, it is possible to carry out concrete curing so that cracks due to temperature changes after placing concrete can always be accurately prevented. As a result, the skeleton made of concrete exhibits good strength and can be a robust structure. In particular, according to the present invention, even in mass concrete in which the internal temperature of the concrete skeleton is apt to rise and abrupt temperature change is likely to occur, it is possible to perform curing so that cracking can be accurately prevented.

Further, in the concrete curing method according to the present invention, if the cooling and heating of the concrete 20 is performed through a gas such as cold air FL-A, FL-B, warm air WL-A, WL-B, The concrete 20 can be cured without using water for cooling or heating the concrete 20. Therefore, it is not necessary to pass the cooling water through the concrete skeleton as in the case where cracking is prevented by the water-cooled concrete cooling method. As a result,
No large-scale equipment for cooling water and circulating the cooled water is required for curing concrete, and the equipment required for curing concrete is lightweight and small. Therefore, concrete curing work can be performed smoothly even in a small space such as on a scaffold. Also,
Since the work of collecting the cooling water from the body is not required after the curing is completed, the work for collecting the water is unnecessary.
In addition, since water is not used, there is no risk that the water used for concrete curing will flow around the reinforcing bars of the skeleton and rust.

Further, the concrete curing apparatus 5 of the present invention
Has a casing such as a distribution box 9, and a plurality of openings 91 and the like are provided in the casing so that the inside and the outside of the casing communicate with each other. The casing has a cooling medium supply means such as a propeller fan 6 and a propeller fan. 6, a heating medium supply means such as a heater 8 is connected, a plurality of space forming members such as a hollow sheath 3 is provided in the mold 23, and each of the plurality of space forming members and a plurality of ports of the casing are connected. Since each of them is configured to be connected via a pipe member such as the flexible hose 10 or the like, the cooling medium supply means and the heating medium supply means are connected from each port of the casing via the pipe member,
A cooling medium such as cold air FL-A or FL-B or a heating medium such as warm air WL-A or WL-B can be freely supplied into the space forming member. Therefore, when the concrete 20 is cast in the formwork 23 to construct the skeleton such as the beam 22, if the cooling medium and the heating medium are selectively supplied to the space forming member, the concrete 20 It can be cooled or heated freely. Therefore, by utilizing this, by cooling the concrete immediately after placing the concrete through the cooling medium supply means, it is possible to prevent the temperature rise of the concrete due to the cement hydration reaction and prevent the cracks caused by the temperature rise. You can Then, after the concrete reaches the maximum temperature, the concrete is heated via the heating medium supply means so as to prevent a rapid temperature decrease of the concrete, and if the temperature decrease rate is adjusted, the It is possible to prevent cracking due to a significant decrease in temperature. Therefore, when the concrete curing device 5 according to the present invention is used, not only the concrete cooling is performed as in the conventional water-cooling type temperature crack prevention method, but also the rapid temperature inside the frame after the concrete reaches the maximum temperature is reached. Since it is possible to avoid a decrease in temperature, it is possible to carry out concrete curing so as to accurately prevent cracking due to temperature changes in the concrete skeleton.

In the concrete curing apparatus 5 of the present invention, the heating medium supply means is composed of cooling medium supply means such as the propeller fan 6 and a heater connected to the cooling medium supply means. The cooling medium supply means can function as a part of the heating medium supply means, if necessary. Therefore, the cooling medium supply means can be used both as the cooling medium supply means at one time and as the heating medium supply means at another time, which simplifies the apparatus configuration of the concrete curing apparatus 5, and It leads to weight reduction and size reduction. Then, even if the concrete body to be cured is located at a high place and it is necessary to place such a concrete curing device on the scaffold, concrete curing can be smoothly performed without burdening the scaffold.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a pier under construction of a beam portion using the concrete curing method according to the present invention.

FIG. 2 is a side view of the pier shown in FIG.

FIG. 3 is a diagram showing a state in which a heating / cooling unit used for bridge pier construction shown in FIG. 1 is performing cooling curing.

FIG. 4 is a diagram showing a state where the warming / cooling unit shown in FIG. 3 is performing heat curing.

5 is a view on arrow V in FIG. 3. FIG.

FIG. 6 is a view on arrow VI of FIG.

FIG. 7 is one of a series of diagrams showing a procedure for performing the concrete curing method according to the present invention.

FIG. 8 is one of a series of diagrams showing a procedure for performing the concrete curing method according to the present invention.

FIG. 9 is one of a series of diagrams showing a procedure for performing the concrete curing method according to the present invention.

FIG. 10 is a diagram showing a relationship between a concrete cross section and a concrete temperature during cooling and curing the concrete using the concrete curing apparatus according to the present invention.

FIG. 11 is a diagram showing the relationship between the concrete cross section and the concrete temperature during heating and curing of concrete using the concrete curing apparatus according to the present invention.

FIG. 12 is a diagram showing an example of a temperature change state of concrete cured according to the present invention.

[Explanation of symbols]

20 ... concrete 22 ... frame (beam) 23 ... formwork FL-A, FL-B ... gas (cold air) WL-A, WL-B ... gas (warm air) 3 ... space forming member (sheath) ) 5 ... Concrete curing device 6 ... Cooling medium supply means, heating medium supply means (propeller fan) 8 ... Heating medium supply means (heater) 9 ... Casing (distribution box) 91 ... Port (insert) 10 ... … Pipe member (flexible hose) T …… Concrete temperature TPL …… Maximum temperature ΔT / D …… Temperature decrease rate VX …… Predetermined value

Claims (4)

[Claims] 1. When placing a skeleton made of concrete, while the temperature of the cast concrete is rising due to the heat of cement hydration, the concrete is cooled, and the temperature-raised concrete reaches a maximum temperature. After that, the concrete is heated, and the temperature of the concrete is adjusted so that the temperature decrease rate after the maximum temperature of the cast concrete is adjusted to a predetermined value or less. Curing method. 2. The concrete curing method according to claim 1, wherein the cooling and heating of the concrete are performed through a gas. 3. A casing, wherein a plurality of ports are provided in the casing such that the inside and the outside of the casing communicate with each other, the cooling medium supply means and the heating medium supply means are connected to the casing, and A concrete curing apparatus, wherein a plurality of hollow space forming members are provided, and each of the plurality of space forming members and each of the plurality of openings of the casing are connected via a pipe member. 4. The concrete curing apparatus according to claim 3, wherein the heating medium supply means comprises the cooling medium supply means and a heater connected to the cooling medium supply means.