KR101348702B1 - Method of preventing cracks in the mass concrete using heating forms heated by microwave - Google Patents

Abstract

The present invention relates to a method for preventing the generation of cracks in mass concrete using a heating form heated by microwaves, and, more specifically, to a method for preventing crack generation due to tensile stress by minimizing temperature variation between the inside and the surface of the mass concrete by controlling temperature in the surface of the mass concrete using a heating form heated by microwaves while the mass concrete for thick members such as a dam, the lower structure of a bridge, a retaining wall, and the foundation of a structure is cured, wherein the temperature variation is generated when the mass concrete is hydrated. According to the present invention, the method used for constructing/curing the mass concrete allows the temperature variation between the central part and the surface part of the mass concrete to be controlled to be minimized by the heating form heated by the microwaves so that: temperature cracks due to thermal stress is prevented; and construction periods for constructing the mass concrete are largely reduced by reducing periods for curing the mass concrete.

Description

Method of preventing cracks in the mass concrete using heating forms heated by microwave}

The present invention relates to a method for preventing cracks caused by heat of hydration generated in the interior of mass concrete, and more particularly to curing mass concrete having a thick thickness such as dams, bridge substructures, retaining walls, and structure foundations. The present invention relates to a method of preventing cracking caused by tensile stress by controlling the temperature of the concrete surface using a heating formwork to minimize the temperature difference between the inside and the surface of the concrete.

In general, concrete is manufactured by mixing cement, gravel, sand, water, and the like at a predetermined ratio, and heat of hydration is generated by a hydration reaction in the process of mixing cement and water. Since the heat of hydration takes a long time to be released to the outside due to the low thermal conductivity of the concrete, a temperature difference occurs between the inside and the outside of the concrete during the hydration process of the concrete.

It is not a big problem because the heat generated from the inside is easily dissipated to the outside in the structure that is relatively thin and has a lot of contact with the outside. In the above-mentioned mass concrete (including 0.5m or more in the structure where the bottom is constrained), thermal cracking is likely to occur due to hydration heat, and recently, high-rise buildings such as business buildings and residential complex buildings in the city center According to the trend, thermal cracking due to hydration heat is also a problem in the lower foundation mat part.

In particular, when the temperature difference of concrete is about 25 ℃ or more, thermal cracking occurs due to thermal stress, and tensile stress caused by heat of hydration remains as residual stress even after curing, acting as a restraint condition on the surrounding concrete, resulting in cracking, safety, durability and It will affect the waterproofness.

The control methods for the cracks of mass concrete are classified into three categories: design control, material control, and construction. Among them, the material control method is a method for reducing the temperature cracking due to the internal and external temperature difference by delaying the curing time by adding an additive such as a curing retardant to concrete, and the Republic of Korea Patent No. 0436235, Korea Patent No. 0581148, Korea Patent No. 0581149, Korean Patent Publication No. 2009-0037622, etc. propose a technique for preventing temperature cracking by adjusting the concrete material.

In addition, as a construction control method, a temperature crack control method by pre-cooling and a temperature crack control method by pipe cooling are used.

The precooling is a method of reducing the temperature crack generation and inherent temperature stress in the structure by lowering the concrete pouring temperature, and includes total temperature reduction management up to the concrete material temperature, the mixing temperature, and the pouring temperature. If the pre-cooling method is largely classified, it can be classified into a cooling stage, a cooling object, and a cooling means, and basically, a method of individually cooling concrete materials using cooling media such as cold water, cold wind, ice, liquid nitrogen, etc. Or a method of directly cooling concrete in a state not hardened after manufacture.

However, this pre-cooling method is not a fundamental solution because the effect of reducing the heat of hydration is minimal.

The pipe cooling method is a kind of post-cooling method, and it is recognized as an effective means for controlling the heat of hydration by arranging pipes prior to concrete pouring and passing water immediately after concrete pouring to reduce the heat of hydration of concrete. As a technology related to the pipe cooling method, various pipe cooling methods are proposed in Korean Utility Model Registration No. 0233675, Korean Patent Registration No. 0530426, and Korean Patent Publication No. 2011-0127399.

However, this pipe cooling method is difficult to recycle because the cooling pipe is embedded in concrete, and when the diameter of the cooling pipe is large, the physical properties may be degraded by the cooling pipe itself, so the concrete space needs to be refilled in the empty space of the cooling pipe. There are various problems such as poor workability, extended construction period due to the installation of cooling pipes, and increased costs due to the price of cooling pipes.

Recently, after installing the roof facilities without using a cooling pipe, a method of preventing temperature cracks by reducing the temperature difference between the center of the concrete and the surface by increasing the surface temperature of the mass concrete by blowing hot air into the interior thereof is used.

However, this method not only consumes excessive fuel costs due to the operation of the hot air blower but also exposes problems such as shrinkage cracking due to excessive drying on the concrete surface directly exposed to the hot air heat.

Some recent techniques have proposed a method of controlling the temperature difference between the inside and outside of the concrete by installing a cage for confining water on top of the mass concrete and a heating means such as a heating wire therein. However, this method requires installation of additional facilities to confine water, takes a long time to construct a hot wire, and confines water so that it can be used only on the upper part of mass concrete and has difficulty in using on the side.

The present invention is to solve the situation and problems as described above, the problem to be solved by the present invention is to minimize the occurrence of the temperature difference between the inside and outside of the concrete during the hydration process after the mass concrete is placed that the cracking occurs It is to provide a way to effectively prevent it.

In order to achieve the above object, the present invention

(1) reinforcing steel bars and installing formwork for mass concrete;

(2) attaching a heating formwork generated by microwaves to the outer surface of the formwork for mass concrete;

(3) installing a temperature sensor in the formwork for mass concrete and placing concrete; And

(4) curing the concrete while measuring the temperature measured in real time by the temperature sensor while controlling the temperature of the exothermic formwork generated by the microwave so that the difference between the inside and the surface temperature of the mass concrete is less than or equal to a certain degree;

It provides a crack prevention method of the mass concrete using a heating formwork generated by the microwaves including a.

The advantages of the crack prevention method of the mass concrete using the heating formwork generated by the microwave according to the present invention are as follows.

1. The construction is excellent because only the module-type heating formwork including the heating part generated by microwaves is installed on the outer surface of the existing formwork for mass concrete, and after the construction of the lower layer is completed, the heating formwork is separated and the upper layer is removed. It is recyclable and economical as well.

2. In addition, by controlling the temperature of the heating formwork while measuring the heat of hydration of the poured concrete in real time by the temperature sensor, it is easy to control the temperature difference and automatic control using a computer is possible.

3. In addition, the heating formwork can be used on the side and top surface of the mass concrete, so the range of application is wide.

4. In addition, by using the temperature generated in the exothermic formwork to promote the hydration of the concrete surface can increase the strength of the concrete has the effect of shortening the curing period.

5. In addition, the concrete is uniformly cured as a whole by reducing the temperature difference between the inside and the outside of the heat formwork, thereby making the concrete more durable.

1 is a step-by-step method of crack prevention of mass concrete using a heating formwork generated by microwaves according to the present invention.
2A to 2B are views showing an example of a heat generating form that is generated by microwaves used in the present invention.
3A and 3B are partial views illustrating an example of a method of preventing cracks in mass concrete using heat generating formwork generated by microwaves according to the present invention.
Figure 4 is a graph showing that the temperature deviation between the inside and the outside of the concrete is reduced when the heat generating form according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

1 is a step-by-step method of crack prevention of mass concrete using a heating formwork generated by microwaves according to the present invention.

As shown in Figure 1 crack prevention method of the mass concrete according to the present invention

(1) reinforcing the reinforcing bars and installing the formwork for mass concrete (S100);

(2) attaching a heating formwork generated by microwaves to the outer surface of the formwork for mass concrete (S200);

(3) installing a temperature sensor in the formwork for mass concrete and placing concrete (S300); And

(4) curing the concrete while measuring the temperature measured in real time by the temperature sensor while controlling the temperature of the heating formwork generated by the microwave so that the difference between the inside and the surface temperature of the mass concrete is less than a certain degree (S400) It is configured to include).

In the method according to the present invention, the heating formwork generated by the microwave is preferably used to be attached to the steel outer surface of the pre-installed mass concrete formwork, it is not necessarily used to attach to it, formwork for mass concrete Exothermic formwork generated by the microwave may be used directly as a formwork for mass concrete.

In addition, although the formwork may be exposed to the outside air in a state where no formwork is installed on the upper portion of the mass concrete, an exothermic formwork generated by the microwave used in the present invention may also be used on the upper portion of the mass concrete.

When the heating formwork according to the present invention is used in direct contact with the surface of concrete, whether the sidewall or upper portion of the mass concrete is used, the heating formwork is attached to the curing sheet while the curing sheet is in contact with the concrete surface. More preferred.

In addition, the upper portion of the mass concrete may be further provided with a protective film that can block the direct contact of the outside air. Such a protective film is preferably installed when the external temperature is low, such as winter, when the heating formwork used in the present invention is installed on the top, it is not necessary to use a protective film, but a complete blocking due to the rebar exposed to the top Since it is difficult, it is more preferable to provide a protective film on the upper part.

In the method according to the present invention, the difference between the inside and the surface temperature of the mass concrete is preferably adjusted to 0 ~ 25 ℃, more preferably to 20 ℃ or less. When the internal / external temperature difference of concrete exceeds 25 ℃, thermal cracking occurs due to thermal stress, and tensile stress caused by heat of hydration remains as residual stress after hardening, acting as a restraint condition on surrounding concrete. This is because it may adversely affect physical properties such as durability and waterproofness.

2a to 2b is a view showing a heat generating form that is generated by the microwave according to an embodiment of the present invention.

As shown in Figures 2a to 2b, the heating dies generated by the microwave according to the present invention includes a microwave generator 15; A waveguide 16 receiving microwaves from the microwave generator 15 and transferring the microwaves into the housing 17; A housing (17) for diffusely reflecting the microwaves transmitted to the waveguide (16); And a heat generating portion 18 that absorbs the diffused microwaves to generate heat and heats the surface of the concrete to be heated by the heat.

In the heat generating form according to the present invention, one of the heat generating portion 18 is attached to the surface of the concrete to be heated or the steel formwork to heat the surface of the target concrete and the other side is configured to be connected to the housing 17.

3A and 3B are partial views illustrating an example of a method of preventing cracks in mass concrete using heat generating formwork generated by microwaves according to the present invention. The form of the heating formwork can be variously modified according to the size, shape, use, etc. of the mass concrete to be manufactured, and the number of waveguides can also be used including one or more. In addition, the heating formwork may be attached to only one surface of the desired mass concrete, or may be attached to two or more surfaces. 3A illustrates an example in which a heating formwork module 100 generated by microwaves is attached to the sidewall of the formwork of mass concrete 110, and FIG. 3B illustrates a heating formwork module 100 generated by microwaves. An example is used to pad the upper side as well as the formwork sidewall of 110. As shown in FIGS. 3A and 3B, the temperature sensor 120 is installed at various points in the poured concrete concrete 110, and the temperature sensor is attached to the form surface (not shown). By using the controller 140 to measure the temperature of the inside of the mass concrete and the temperature of the form surface in real time to prevent temperature cracking by controlling the temperature generated in the heating formwork 100 to minimize the temperature deviation. In FIG. 3A, the controllers are shown to operate collectively from the outside. However, the controllers are not necessarily required to do this, and each heating formwork module 100 may be individually provided with controllers to control them individually. It belongs to the scope of the invention. In addition, in FIG. 3B, only the heating formwork module 100 of the side wall is illustrated as being connected to the controller 140, but the heating formwork module 100 of the upper part of the mass controller may also be collectively or individually by an external controller or an individual controller. Temperature can be controlled, which is also within the scope of the present invention.

Hereinafter will be described in detail with reference to Figures 2a and 2b with respect to the structure of the heat generating form heat generated by the microwave used in the present invention.

In the heating die according to the present invention, the waveguide 16 is preferably connected to the outside of the housing 17 and the heat generating unit 18 is preferably modularized in the form mounted inside the housing. At this time, the heat formwork module 100 according to the present invention may further include a box-shaped outer case 20 to protect the internal device. In actual construction, the module-type heat formwork may be attached to the steel formwork as it is in the field, or in some cases, the module may be used as it is without the steel formwork.

In the heating die according to the present invention, the material of the waveguide 16 is preferably made of steel, aluminum, or copper, but is not necessarily limited thereto, and may be used without limitation as long as the material can effectively reflect microwaves. .

In the heating die according to the present invention, the housing 17 preferably has a tapered structure in which the width of the portion connected to the heat generating portion is wider than the width of the portion connected to the waveguide 16. In this case, the diffuse reflection of the microwave occurs smoothly and the microwaves can be irradiated to the heat generating unit 18 as a whole, thereby generating heat evenly. However, it is not necessarily a tapered structure, but a rectangular housing is also possible. (See the right view of FIGS. 2A and 2B)

In the heating die according to the present invention, the microwave generator 15 may include a high voltage transformer and a magnetron (MGT), and may further include a high voltage capacitor and a high voltage diode. The high voltage transformer converts the commercial AC voltage input from the outside into a high voltage suitable for high frequency generation (for example, about 4 kilovolts [kV]) and applies it to the magnetron. The magnetron generates high frequency oscillation by the high voltage applied from the high voltage transformer. To generate microwaves.

The microwave frequency should use ISM (Industrial, Scientific and Medical) frequency, but it is preferable to use the 2,450 MHz band mainly to take advantage of the smoothness of supply and demand, but the present invention is not limited thereto. Microwaves having a frequency in the 300 GHz region can be variously used.

When the magnetron is driven, a cooling fan is installed around the magnetron to cool the high heat generated from the magnetron, the cooling fan is connected to the fan motor, and when a commercial AC voltage is applied to the fan motor, the fan motor is operated. The cooling fan is driven by the fan motor to blow external cold air to the magnetron, thereby cooling the high heat generated in the magnetron. However, cooling fans may be excluded when separate cooling devices are not required, such as when using other devices for cooling the magnetron or when exposed to the outside.

The microwave generator 15 is fixed to one of the side, top and bottom surfaces of one end of the waveguide 16 by a fixing bracket, and one end of the waveguide 15 by a connecting tube protruding from the microwave generator 15. By being communicatively coupled to, the microwave generated from the microwave generator 15 can be delivered to one end of the waveguide 16. It is also possible to connect the waveguide long so that the microwaves are evenly transmitted throughout the housing.

In the heating die according to the present invention, the waveguide 16 may be exposed to the outside of the housing 17 or may be embedded in the inside of the housing. When exposed to the outside, the microwave generator 15 may be installed on one side, the upper surface, or the lower surface of the exposed waveguide 16. In addition, when embedded in the inside of the housing 17 may not be exposed to the outside. At this time, it is preferable that the front end of the embedded waveguide 16 has a tapered structure in order to smooth the diffuse reflection of the microwaves. The cross-sectional shape of the waveguide 16 may be any shape such as a rectangular shape, a circular shape or a triangular shape, and the like is not particularly limited but may be selected and used according to the use or need.

In the heat generating form according to the present invention, the heat insulating portion 19 may be further included in one side opposite to the heating target of the heat generating portion. The material of the heat insulating portion 19 is a material that can pass as it is without absorbing microwaves and is heat resistant, and specific examples thereof include glass wool, concrete, gypsum, heat resistant plastic, heat resistant ceramic, heat resistant paper or stone powder. Etc. may be used, but the present invention is not limited thereto.

In the heat generating form according to the present invention, the heat generating unit 18 may be configured in a form in which the non-heat generating material supports the heat generating material, and each heat generating material may be configured to be separated from each other. In this case, the non-heat generating material may be glass wool, concrete, gypsum, heat-resistant plastic, heat-resistant ceramic, heat-resistant paper or stone powder, but is not limited thereto. In addition, an upper surface of the heat generating unit 18 may further include a panel. In this case, the material of the panel is preferably a material capable of dispersing the generated heat, and specific examples may include steel, aluminum, or copper, but are not limited thereto.

In the heat generating die according to the present invention, the heat generating unit 18 uses a ceramic material that is generated by microwaves of 300 MHz to 300 GHz. For such a material, the inventors of the present invention can use the material proposed through a separate Korean patent application (10-2011-0032313). The contents described in the Republic of Korea Patent Application 10-2011-0032313 is to be interpreted to be included in the present invention by reference. The heating material described in the Republic of Korea Patent Application 10-2011-0032313 refers to a metal oxide containing composition containing at least 4% by weight of at least one iron oxide compound of Fe2O3, Fe3O4 and FeO, such material is a short time by a microwave of 300MHz ~ 300GHz Since it is possible to generate heat up to a high temperature, it is suitable for use in the exothermic formwork according to the present invention. In more detail, the metal oxide-containing composition has a particle size of 10 mm or less and a spherical ratio of 0.5 or more, a quenched steel slag composition having a particle size of 10 mm or less, a slow cooling steelmaking slag composition having a particle size of 10 mm or less, a copper smelting slag composition having a particle size of 10 mm or less, a particle size of 10 mm or less One or more selected from the group consisting of zinc smelting slag composition, red mud composition having a particle size of 1 mm or less, hematite composition having a particle size of 25 mm or less, refined coal ash composition having a particle size of 10 mm or less, and refined loess composition having a particle size of 1 mm or less may be used. It is not limited.

In addition, in the present invention, in addition to the heating material described in the Korean Patent Application No. 10-2011-0032313, water, oil, carbon, SiC, or the like may be further included in the heating unit. In addition, it is to be interpreted that the material of the heat generating part used in the present invention includes any material capable of generating heat by microwaves such as water, oil, carbon, SiC, or the like as used alone or in combination. In the present invention, such a material that can be generated by microwaves is called MIP (microwave-irradiated pyrogen).

Figure 4 is a conceptual diagram showing that the temperature deviation between the center (inside) and the surface (outside) of the concrete is reduced when using the heat generating form according to the present invention. As can be seen in Figure 4, when the heating formwork according to the present invention does not use a large temperature difference between the concrete center and the surface, but using the heating form according to the present invention greatly increases the temperature difference between the concrete center and the surface In addition, there is an effect that can significantly shorten the curing period using the formwork.

Crack prevention method of the mass concrete according to the present invention is described in the order of (1) to (4), but the number does not mean the order should be interpreted to be variously modified according to site conditions or required quality. do.

In addition, the crack prevention method of the mass concrete according to the present invention is characterized in that it uses a heat-generating formwork that is generated by microwaves, but does not exclude the existing method of pre-cooling or pipe cooling, and to control to reduce the temperature difference Precooling, pipe cooling or both may be used together as a means for this.

Pre-cooling is the cooling of concrete material before or after pouring by using cold water, cold wind, ice, liquid nitrogen, etc. Pipe cooling is to arrange the pipes before the concrete is placed and transfer the refrigerant into the pipes immediately after the concrete is placed. In the present invention, such a method of precooling and pipe cooling can be used together as a method of reducing the temperature.

In this case, when controlling the difference between the inside and the surface temperature of the concrete by using pipe cooling, water, liquefied nitrogen, or the like may be used as the refrigerant. In addition, the cooling pipe used at this time may be a steel pipe or copper pipe. In the case of using such a pipe cooling method, if the temperature difference between the concrete and the refrigerant around the cooling pipe is too large, there is a possibility that cracking may occur around the cooling pipe.

In addition, as a method using the method, the mass concrete, characterized in that the difference in the internal and surface temperature is controlled to 0 ~ 25 ℃ by using a heat generating form that is generated by the microwave is also included in the scope of the present invention. The mass concrete can be used in the curing process of mass concrete, such as dams, bridge substructures, various structural foundations, and nuclear power plant structures. Effective in In addition, the construction and economical efficiency can also be significantly improved, and when the outside air temperature is low, such as in winter, it is expected to shorten the overall construction period because it has an effect of promoting hydration.

As described above, the features of the present invention have been described in detail with reference to the drawings, but the present invention may be variously modified and changed by those skilled in the art and such modifications and changes should be interpreted as belonging to the protection scope of the present invention. will be.

15: Microwave generator 16: Waveguide
17 housing 18 heating portion
19: heat insulation 20: outer case
100: formwork module 110: mass concrete
120: mass concrete internal temperature sensor
130, 130 ': Wire 140: Controller

Claims (27)

Laying the reinforcing bars and installing formwork for mass concrete;
Attaching a heating formwork generated by microwaves to an outer surface of the formwork for mass concrete;
Installing a temperature sensor in the formwork for mass concrete and pouring concrete; And
Curing the concrete by measuring the temperature measured in real time by the temperature sensor while controlling the temperature of the heat generating form generated by the microwave so that the difference between the inside and the surface temperature of the mass concrete is less than or equal to a certain degree;
Containing, the exothermic formwork generated by the microwave
A microwave generator 15;
A waveguide (16) for receiving microwaves from the microwave generator and transferring the microwaves into the housing;
A housing 17 which diffusely reflects the microwaves delivered to the waveguide; And
The heat generating unit 18 absorbs the diffused microwaves to generate heat and heats the surface of the concrete to be heated by the heat.
Crack prevention method of mass concrete using a heating formwork generated by microwaves, characterized in that configured to include.
The method of claim 1, wherein the heat generating form heat generated by the microwave is directly used as formwork for mass concrete without the formwork for mass concrete.
The method of claim 1, wherein the heat generating form heat generated by the microwave is also used on the upper portion of the mass concrete.
The method of claim 1 or 3, wherein a protective film facility is further installed on the mass concrete, and the crack prevention method of the mass concrete using the exothermic formwork generated by the microwaves.
The method of claim 1, wherein the difference between the inside and the surface temperature of the mass concrete is controlled to 0-25 ° C. The crack prevention method of the mass concrete using the heating form heat generated by the microwave.
delete The method according to claim 1, wherein one side of the heat generating unit 18 is attached to the surface of the target concrete to heat the surface of the target concrete and the other is connected to the housing 17 using heat generating form heat generated by microwaves How to prevent cracking in mass concrete.
The heat generating part of claim 1, wherein the waveguide (16) is connected to the outside of the housing (17) and the heat generating part (18) is modularized in a form mounted on the inside of the housing (17). Method for preventing cracks in mass concrete using formwork.
The method of claim 1, wherein the waveguide (16) is made of steel, aluminum, or copper material.
The method of claim 1, wherein the microwave generator (15) comprises a high voltage transformer and a magnetron. The method of preventing cracks in mass concrete using exothermic formwork generated by microwaves.
The method of claim 10, wherein a cooling fan is installed around the magnetron, the cooling fan is connected to the fan motor, and when a commercial AC voltage is applied to the fan motor from outside, the fan motor is driven and the cooling fan is driven by the fan motor. A method of preventing cracks in mass concrete using exothermic formwork generated by microwaves, wherein the external cold air is blown to the magnetron to cool the high heat generated from the magnetron.
12. The exothermic formwork generated by microwaves according to claim 11, wherein the waveguide 16 is exposed to the outside of the housing 17, and a microwave generator is installed on one side, the upper surface, or the lower surface of the exposed waveguide. Crack prevention method of mass concrete using
The method of claim 1, wherein the waveguide (16) is embedded in the inside of the housing (17) so that it is not exposed to the outside.
The method of claim 1, wherein one side of the heat generating unit (18) opposite to the heating target further includes a heat insulating unit (19).
The method of claim 1, wherein the upper surface of the heat generating portion (18) further comprises a panel (panel), characterized in that the crack prevention method of the mass concrete using heat generating form heat generated by the microwave.
The method of claim 15, wherein the material of the panel is steel, aluminum, or copper material.
The method of claim 1, wherein the heat generating unit uses a ceramic material that is generated by microwaves of 300 MHz to 300 GHz.
18. The method of claim 17, wherein the ceramic material is a metal oxide containing composition containing at least 4% by weight of at least one iron oxide compound of Fe 2 O 3, Fe 3 O 4, and FeO. 18.
The composition of claim 18, wherein the metal oxide-containing composition has a particle size of 10 mm or less and a spherical ratio of 0.5 or more. At least one selected from the group consisting of a smelting slag composition, a red mud composition having a particle size of 1 mm or less, a hematite composition having a particle size of 25 mm or less, a refined coal ash composition having a particle size of 10 mm or less, and a refined loess composition having a particle size of 1 mm or less. Crack prevention method of mass concrete using exothermic formwork.
The composition of claim 18, wherein the metal oxide-containing composition has a particle size of 10 mm or less and a spherical ratio of 0.5 or more. At least one selected from the group consisting of a smelting slag composition, a red mud composition having a particle size of 1 mm or less, a hematite composition having a particle size of 25 mm or less, a refined coal ash composition having a particle size of 10 mm or less, and a refined loess composition having a particle size of 1 mm or less. Crack prevention method of mass concrete using exothermic formwork.
The method of claim 17, wherein the heat generating unit further comprises at least one selected from water, oil, carbon, and SiC in the ceramic material.
delete The method of claim 1, further comprising controlling the difference between the inside and the surface temperatures of the concrete by using precooling or pipe cooling.
24. The method of claim 23, wherein controlling the difference between the inside and the surface temperatures of the concrete by using pipe cooling uses water or liquefied nitrogen as the refrigerant. .
24. The method of claim 23, wherein controlling the difference between the internal and surface temperatures of the concrete using pipe cooling comprises using steel pipes or copper pipes as cooling pipes. Prevention method.
Mass concrete produced by the method of claim 1, characterized in that the difference between the internal and surface temperature is controlled to 0 ~ 25 ℃ by using a heat generating form that is generated by microwaves.
27. The mass concrete of claim 26 used in a dam, bridge substructure, structure foundation or nuclear power plant structure.

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