Mass concrete temperature control system and mass concrete temperature control method

Abstract

To solve problems associated with temperature control of mass concrete that existed in conventional construction methods.SOLUTION: A mass concrete temperature control system includes a plurality of temperature control devices 10 inserted vertically downward from the surface side of mass concrete C, a controller 20 controlling electric conduction to each of the temperature control devices 10, and a current carrying wire 30 connecting each of the temperature control devices 10 and the controller 20. The temperature control device 10 includes a cylindrical insert member 110 made of a material with high thermal conductivity such as aluminum, a Peltier element group 100 arranged along the inner circumferential surface of the insert member 110, an inner wall 120 provided in the circumferential and axial directions between both ends (upper end and lower end) of the insert member 110 located inside the Peltier element group 100, a plugging material 130 that plugs the circumferential gap between the inner wall 120 and the insert member 110, and a base material 140 that plugs the opening at the axial lower end of the space formed by the inner wall 120.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a technique for controlling the temperature of placed mass concrete.

Background Art

[0002] It is known that cracks occur in concrete due to the reaction between water and cement during the hardening process of concrete, generating heat of hydration. Particularly in concrete structures such as dams and bridge piers constructed by placing a large amount of concrete (mass concrete), appropriately taking measures against cracks in mass concrete is important from the perspective of the quality of the structure. Therefore, as construction methods for controlling the temperature of mass concrete, a pipe cooling method and a heat pipe method are known. However, the pipe cooling method has the drawback that the water supply equipment becomes large-scale. In the heat pipe method, although water supply is not required, there are problems such as difficulty in accurately controlling the cooling temperature, the need to secure space above the insertion location of the heat pipe, and the labor and cost required for transporting the heat pipe. Further, for example, Patent Document 1 discloses a method of providing cooling means on the back surface of a concrete formwork.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, an object of the present invention is to provide a system and method that solve the problems in conventional methods in the temperature control of mass concrete and perform simple and effective temperature control.

Means for Solving the Problems

[0005] To solve the above problems, the present invention provides a mass concrete temperature control system comprising: a cylindrical insertion member inserted into a sheath pipe inserted into a cast mass concrete; a group of thermoelectric elements arranged axially along the inner circumferential surface of the insertion member; an inner wall material provided circumferentially and axially between both ends of the insertion member inside the group of thermoelectric elements; a sealing material that closes both ends of the gap between the inner wall material and the lower end of the insertion member; and a bottom material that closes the opening at the axial lower end of the space formed by the inner wall material; and a controller that controls the supply of current to the group of thermoelectric elements. The group of thermoelectric elements exerts a heat absorption or heat dissipation effect on the insertion member side and a heat dissipation or heat absorption effect on the inner wall material side when current is supplied.

[0006] The insertion member, the inner wall material, and the group of thermoelectric elements of 1 are considered as one set, and multiple sets may be connected and arranged in the axial direction according to the insertion length of the sheath pipe into the mass concrete.

[0007] At least a portion of each of the two sides of the thermoelectric element group that exhibit a heat absorption or heat dissipation effect may be arranged to be in contact with the inner circumferential surface and the inner wall material, and the side of the thermoelectric element group that exhibits a heat absorption or heat dissipation effect may be switched depending on the direction of current flow.

[0008] The insertion member and the inner wall material may have a polygonal shape in their horizontal cross-section, and the thermoelectric element group may be provided on each face of the polygon.

[0009] When the inner wall material side end face of the thermoelectric element group is the surface that emits the heat dissipation effect of the thermoelectric element group, a cooling member may be placed in the space to dissipate the heat dissipated into the space to the outside of the mass concrete.

[0010] The cooling element may be dry ice, ice, or cold water.

[0011] The concrete temperature control method of the present invention comprises a sheath pipe insertion step of inserting a sheath pipe into cast mass concrete; a temperature control device insertion step of inserting the temperature control device described in claim 2 into the sheath pipe; an injection step of injecting a heat conductive liquid between the sheath pipe and the temperature control device; an energizing step of energizing the thermoelectric element group of the temperature control device; and a thermal control step of causing the thermoelectric element group to exhibit a heat absorption effect or a heat dissipation effect on the insertion member side and a heat dissipation effect or a heat absorption effect on the inner wall material side depending on the direction of current flow.

[0012] In the thermal control step, depending on the vertical position of the temperature control device in the mass concrete, the thermoelectric element group may be configured to exhibit a heat absorption effect or a heat dissipation effect on the insertion member side.

[0013] In the step of inserting the temperature control device, multiple temperature control devices may be inserted into the sheath pipe inserted into the mass concrete at predetermined intervals and insertion lengths. [Effects of the Invention]

[0014] According to the present invention, in controlling the temperature of mass concrete, the internal temperature of the mass concrete can be controlled by simply switching the surface of the thermoelectric element group that exhibits a heat absorption effect or a heat dissipation effect depending on the direction of current flow to the group of thermoelectric elements, thereby resolving the problems of conventional construction methods. [Brief explanation of the drawing]

[0015] [Figure 1] A diagram showing an example of the configuration of a mass concrete temperature control system according to an embodiment of the present invention. [Figure 2] A plan view illustrating the arrangement of the temperature control device according to the same embodiment. [Figure 3] A diagram illustrating the heat dissipation and heat absorption effects of a Peltier element. [Figure 4] A vertical cross-sectional view of a temperature control device showing the arrangement of thermoelectric elements according to the same embodiment. [Figure 5] A horizontal cross-sectional view of a temperature control device showing the arrangement of thermoelectric elements according to the same embodiment. [Figure 6] A plan view illustrating the functional effects of a modified temperature control device. [Modes for carrying out the invention]

[0016] An example of an embodiment for carrying out the present invention will be described. Figure 1 is a diagram showing an example of the configuration of a mass concrete temperature control system according to an embodiment of the present invention. The mass concrete temperature control system comprises a plurality of sheath pipes 11 inserted vertically downward from the surface side of the mass concrete C, a plurality of temperature control devices 10 inserted into each of the sheath pipes 11, a controller 20 that controls the supply of power to each temperature control device 10, and power supply lines 30 that connect each temperature control device 10 and the controller 20. Each sheath pipe 11 and the temperature control device 10 inserted into each sheath pipe 11 are arranged at predetermined intervals from each other within the formwork of the mass concrete C, as illustrated in Figure 2.

[0017] Each temperature control device 10 incorporates a Peltier element 100, which is a thermoelectric element of the present invention. Hereinafter, the thermoelectric element will also be referred to as a Peltier element. As illustrated in Figure 3, the Peltier element 100 consists of a P-type semiconductor 101, an N-type semiconductor 102, and metals 103, 104, and 105. The Peltier element 100 is a thermoelectric element that exhibits a heat dissipation effect and a heat absorption effect depending on the direction of the current flow when a DC current is passed through it. Specifically, as illustrated in Figure 3, when the direction of current flow from the power supply 106 is direction A, a heat absorption effect is exhibited on the metal 103 side, and a heat dissipation effect is exhibited on the metals 104 and 105 side. On the other hand, when the current is passed in the opposite direction to direction A, a heat dissipation effect is exhibited on the metal 103 side, and a heat absorption effect is exhibited on the metals 104 and 105 side. The controller 20 controls the magnitude of the heat absorption or heat dissipation effect, and the side of the element that exhibits the heat absorption or heat dissipation effect, by controlling the power supply to the Peltier element group 100, specifically the magnitude of the DC current supplied and the direction of the current supply. By using Peltier elements as thermoelectric elements in this way, it becomes possible to use a relatively small battery as the power source.

[0018] Figure 4 is a vertical cross-sectional view showing the structure of the temperature control device 10, and Figure 5 is a horizontal cross-sectional view showing the arrangement of Peltier elements, which are thermoelectric elements, within the temperature control device 10. The temperature control device 10 is inserted into a sheath pipe 11 inserted into a mass concrete C. The temperature control device 10 comprises a cylindrical insertion member 110 made of a highly thermally conductive material such as aluminum, a group of Peltier elements 100, 100, 100… (hereinafter collectively referred to as the Peltier element group 100) arranged along the inner circumferential surface of the insertion member 110, an inner wall material 120 provided circumferentially and axially between both ends (upper and lower ends) of the insertion member 110 inside the Peltier element group 100, a sealing material 130 that closes the circumferential gap between the inner wall material 120 and the lower end of the insertion member 110, and the circumferential gap between the insertion member 110 and the sheath pipe 11, and a bottom material 140 that closes the opening at the axial lower end of the space formed by the inner wall material 120. Note that in Figures 4 and 5, the dimensions of each part differ from those of an actual implementation in order to illustrate the structure of the temperature control device 10 in an easy-to-understand manner. Note that a plugging material 130 for closing the circumferential gap between the insertion member 110 and the sheath tube 11 may be provided as necessary.

[0019] Each Peltier element 100 is connected to the controller 20 by an energizing wire (not shown). Both side surfaces that exhibit the heat absorption effect or the heat dissipation effect of each Peltier element are arranged so as to be at least partially in contact with the inner peripheral surface of the insertion member 110 and the outer peripheral surface of the inner wall member 120, respectively. Each Peltier element 100 is configured to exhibit a heat absorption effect on the insertion member 110 side and a heat dissipation effect on the inner wall member 120 side when a current is energized in a certain direction by the controller. Further, each Peltier element 100 can also exhibit a heat dissipation effect on the insertion member 110 side and a heat absorption effect on the inner wall member 120 side when a current is energized in the direction opposite to the above certain direction by the controller 20. Note that the insertion member 110 and the inner wall member 120 are preferably made of metal, and more preferably made of metal with good thermal conductivity, in consideration of the heat absorption and heat dissipation effects of the Peltier element 100. Further, a solution obtained by mixing a heat storage material, sodium sulfate, and a hydrated solution is filled as the heat conduction liquid 12 in the gap between the insertion member 110 and the sheath tube 11.

[0020] In the present embodiment, the Peltier element group 100 is modularized on a copper substrate. By making the substrate made of copper, it contributes to low heat capacity, excellent heat uniformity, fast temperature responsiveness, and little temperature variation. Further, each module is coated with resin, thereby improving the resistance to corrosion by condensed water.

[0021] When the total axial insertion length of the temperature control device 10 into the sheath pipe 11 inserted into the mass concrete C is several meters, multiple insertion members 110 and inner wall materials 120 of a predetermined length (e.g., 1 m) are connected in the longitudinal direction. In other words, in this case, one insertion member 110, one inner wall material 120, and a group of Peltier elements 100 placed between the insertion member 110 and the inner wall material 120 constitute one set, and multiple such sets are connected and arranged in the axial direction within the insertion range into the mass concrete C. By connecting multiple temperature control devices of a predetermined length in this way, it is possible to flexibly adapt to the pouring height of the mass concrete. Furthermore, even if there are limitations on the airspace above the mass concrete pouring area, the total length can be adjusted by connecting multiple temperature control devices, thus enabling labor and manpower savings in the work from transportation to installation.

[0022] Furthermore, when multiple insertion members 110 and inner wall materials 120 are connected and arranged, the bottom material 140 is provided only on the lowest inner wall material 120 in order to dissipate the heat radiated into the space on the inner circumferential surface side of the inner wall material 120 upwards. Similarly, the sealing material 130 at the lower end of the gap between the insertion member 110 and the inner wall material 120 is also provided only at the lowest end.

[0023] If the inner wall material 120 is the surface that emits the heat dissipation effect of the Peltier element group 100, a cooling member 150 such as dry ice, ice, or cold water is placed in the space formed by the inner wall material 120. This cooling member 150 is used to dissipate the heat dissipated into the space to the outside of the mass concrete.

[0024] Furthermore, when there is a gap between the sheath tube 11 into which the temperature control device 10 is inserted and the insertion member 110, a solution of sodium sulfate and its hydrated solution is filled as a heat conductive liquid 12 in order to transfer the heat dissipation and heat absorption effects of the Peltier element group 100 to the sheath tube 11.

[0025] The insert member 110 may be a hollow tube with a circular cross-section, similar to the sheath tube 11 which has a circular cross-section, as illustrated in Figure 5(A), or it may be a hollow tube with a polygonal cross-section (for example, a hexagon), unlike the sheath tube 11 which has a circular cross-section, as illustrated in Figure 5(B). By making the cross-section of the insert member 110 columnar in this way, stress concentration can be alleviated and long-term durability can be improved. In the case of Figure 5(B), modules of the Peltier element group 100 are provided on each face of the polygon (hexagon in the figure). In the case of Figure 5(A), that is, when the insertion member 110 and the inner wall material 120 are circular, the Peltier element group 100 is arranged so that at least a part of it is in contact with the inner circumferential surface of the insertion member 110 and the inner wall material 120, or the gap between the insertion member 110 and the inner wall material 120 is also circular. Therefore, a flexible Peltier element group 100 (for example, the flexible Peltier module AR-TEM-es-02 manufactured by Asahi Rubber Co., Ltd.) which combines a Peltier element and rubber can be used as the Peltier element 100 to be installed in the gap, thereby accommodating curved surfaces.

[0026] The procedure for the method according to this embodiment is as follows. First, the worker inserts a plurality of sheath pipes 11 into the poured mass concrete, and then inserts a temperature control device 10 into each sheath pipe 11. At this time, the worker inserts multiple temperature control devices 10 into the poured mass concrete at predetermined intervals and insertion lengths. The predetermined intervals and insertion lengths referred to here are intervals and insertion lengths that are sufficient to control the internal temperature of the poured concrete. Furthermore, if there is a gap between the sheath pipe 11 into which the temperature control device 10 is inserted and the insertion member 110, the worker fills that gap with a heat-conducting liquid 12.

[0027] Furthermore, although the sheath pipe 11 is inserted into the mass concrete and then the temperature control device 10 is inserted into the sheath pipe 11, the temperature control device 10 may be inserted into the sheath pipe 11 beforehand, and then the sheath pipe 11 with the temperature control device 10 inserted into it may be inserted into the mass concrete at predetermined intervals and insertion lengths.

[0028] Next, the operator operates the controller 20 to energize the Peltier element group 100 built into each temperature control device 10. Depending on the direction of this current flow, the Peltier element group 100 will either exhibit a heat absorption effect on the insertion member 110 side and a heat dissipation effect on the inner wall material 120 side, or it will exhibit a heat dissipation effect on the insertion member 110 side and a heat absorption effect on the inner wall material 120 side. At this time, the operator adjusts the magnitude of the DC current supplied from the controller 20 and its direction to set the magnitude of the heat absorption or heat dissipation effect, and the side on which the heat absorption or heat dissipation effect is exhibited. This makes it possible to appropriately control the internal temperature of the mass concrete.

[0029] According to the embodiment described above, accurate temperature control can be achieved by appropriately controlling the heat absorption or heat dissipation effect of the temperature control device 10 with the current supplied. Because such accurate temperature control can be achieved, the number of temperature control devices 10 that need to be installed can be reduced, thereby improving work efficiency.

[0030] Furthermore, even if there is a gap between the insertion member 110 and the sheath tube 11, the heat dissipation or absorption effect of the Peltier element group 100 is transmitted to the mass concrete C via the sheath tube 11 by the heat conductive liquid 12 filling the gap, so that the internal temperature of the mass concrete C can be appropriately controlled.

[0031] Furthermore, since the temperature of the mass concrete is controlled from within, it is possible to eliminate the temperature difference between the inside and outside more efficiently compared to, for example, controlling the temperature from outside the formwork.

[0032] Furthermore, since the Peltier elements 100 are modularized, even if some of the Peltier elements 100 are damaged, they can be replaced in module units, which ultimately contributes to cost reduction.

[0033] [Differentiation] The above-described embodiment may be modified as follows. As mentioned above, the side exhibiting the heat absorption or heat dissipation effect can be switched depending on the direction of current flow to the Peltier element 100. As is well known, the surface temperature of cast mass concrete is kept from rising due to heat dissipation (heat transfer) to the outside air through contact with the outside air. However, heat dissipation becomes more difficult towards the center of the mass concrete, resulting in a significant temperature difference between the inside and outside of the mass concrete. This causes thermal expansion in the inside and less thermal expansion in the outside, leading to temperature cracks due to internal constraint. Therefore, the side exhibiting the heat absorption or heat dissipation effect may be switched depending on the vertical position of the temperature control device 10 relative to the mass concrete.

[0034] Specifically, in the example shown in Figure 6, a single temperature control device 10 is constructed by connecting insertion members 110a, 110b and inner wall materials 120a, 120b of predetermined lengths, and the spaces formed by the inner wall materials 120a, 120b are connected. In this case, the temperature control device 10b located towards the center of the mass concrete C exhibits a heat absorption effect on the insertion member 110b side and a heat dissipation effect on the inner wall material 120b side. On the other hand, the temperature control device 10a located on the outer periphery of the mass concrete C exhibits a heat dissipation effect on the insertion member 110a side and a heat absorption effect on the inner wall material 120a side. In other words, in the central area of ​​the mass concrete C, the heat absorption effect is exhibited on the insertion member 110b side and the heat dissipation effect is exhibited on the inner wall material 120b side, while in the outer periphery of the mass concrete C, the heat absorption effect is exhibited on the inner wall material 120a side and the heat dissipation effect is exhibited on the insertion member 110a side. As a result, the Peltier element 100a, positioned on the outer periphery of the mass concrete C, can utilize the heat radiated into the space of the inner wall material 120b by the Peltier element 100b positioned towards the center of the mass concrete to absorb heat from the inner wall material 120a side and radiate heat to the insertion member 110a side. This reduces the temperature difference between the center and outer periphery of the mass concrete, thereby achieving a greater effect in preventing temperature cracks caused by internal restraint. When using this modified example, it is desirable to provide partition walls made of a material with low thermal conductivity (e.g., acrylic) on the outer periphery of the insertion member 110, according to the positions of the Peltier element group 100b and Peltier element group 100a, so as not to affect the heat absorption and heat dissipation effects of the heat conductive liquid 12 filled in the gap between the insertion member 110 and the sheath pipe 11, thereby blocking heat transfer by convection. It is even more desirable to provide multiple partition walls spaced apart as needed.

[0035] Although embodiments for carrying out the present invention have been described above, the present invention is not limited to these, and various modifications are possible within the scope of the technical idea of ​​the present invention. For example, although the temperature control device 10 is inserted perpendicularly to the poured mass concrete, it may also be inserted at an angle so that it opens upward to allow heat to be dissipated to the outside through the space created by the inner wall material 120.

[0036] Furthermore, the temperature control devices 10 may be arranged in a planar manner such that more are placed towards the center of the poured mass concrete and fewer are placed on the outer periphery.

[0037] According to the present invention, temperature control can be easily performed on cast mass concrete, and heat control can be performed according to the location of the concrete, thereby providing an optimal crack prevention effect.

[0038] Furthermore, the present invention may also be a method for controlling the temperature of mass concrete, comprising: a sheath pipe insertion step of inserting a sheath pipe into cast mass concrete; a temperature control device insertion step of inserting the temperature control device described in claim 2 into the sheath pipe; an injection step of injecting a heat conductive liquid between the sheath pipe and the temperature control device; an energizing step of energizing the thermoelectric element group of the temperature control device; and a thermal control step of causing the thermoelectric element group to exhibit a heat absorption effect or a heat dissipation effect on the insertion member side and a heat dissipation effect or a heat absorption effect on the inner wall material side depending on the direction of current flow. [Explanation of Symbols]

[0039] 10, 10a, 10b: Temperature control device, 11: Sheath tube, 12: Heat conductive liquid, 20: Controller, 30: Power supply wire, 100, 100a, 100b: Peltier element, 110, 110a, 110b: Insertion member, 120, 120a, 120b: Inner wall material, 130: Sealing material, 140: Bottom material, 150: Cooling member, C: Mass concrete.

Claims

1. A temperature control device comprising: a cylindrical insertion member inserted into a sheath pipe inserted into cast mass concrete; a group of thermoelectric elements arranged axially along the inner circumferential surface of the insertion member; an inner wall material provided circumferentially and axially between the two ends of the insertion member inside the group of thermoelectric elements; a sealing material that closes both ends of the gap between the inner wall material and the lower end of the insertion member; and a bottom material that closes the opening at the axial lower end of the space formed by the inner wall material. The system includes a controller that controls the supply of current to the group of thermoelectric elements, The thermoelectric element group exhibits a heat absorption or heat dissipation effect on the insertion member side and a heat dissipation or heat absorption effect on the inner wall material side when an electric current is passed through it, in a mass concrete temperature control device.

2. The insert member 1, the inner wall material 1, and the group of thermoelectric elements are considered as one set. Multiple sets are connected and arranged axially, depending on the insertion length of the sheath pipe into the mass concrete. The mass concrete temperature control device according to claim 1.

3. At least a portion of each of the two sides of the thermoelectric element group that exhibit a heat absorption or heat dissipation effect is arranged to be in contact with the inner circumferential surface and the inner wall material. Depending on the direction of current flow, the surface of the thermoelectric element group that exhibits a heat absorption effect or a heat dissipation effect is switched. The mass concrete temperature control device according to claim 2.

4. The insert member and the inner wall material have a polygonal shape in their horizontal cross-section. The thermoelectric element group is provided on each face of the polygon. The mass concrete temperature control device according to claim 1 or 2.

5. When the inner wall material side end face of the thermoelectric element group is the surface that generates the heat dissipation effect of the thermoelectric element group, A cooling member is placed within the space to dissipate the heat radiated into the space to the outside of the mass concrete. The mass concrete temperature control device according to claim 1 or 2.

6. The cooling element is dry ice, ice, or cold water. The mass concrete temperature control device according to claim 5.

7. A sheath pipe insertion step for inserting a sheath pipe into the poured mass concrete, A temperature control device insertion step of inserting the temperature control device described in claim 2 into the sheath tube, An injection step of injecting a heat conductive liquid between the sheath tube and the temperature control device, The energizing step involves energizing the thermoelectric element group of the temperature control device, A thermal control step in which, depending on the direction of current flow, the thermoelectric element group exhibits a heat absorption or heat dissipation effect on the insertion member side and a heat dissipation or heat absorption effect on the inner wall material side of the thermoelectric element group, A mass concrete temperature control method comprising the following:

8. In the thermal control step, depending on the vertical position of the temperature control device in the mass concrete, the thermoelectric element group is made to exhibit a heat absorption effect or a heat dissipation effect on the insertion member side. The method for controlling the temperature of mass concrete according to claim 7.

9. In the step of inserting the temperature control device, a plurality of the temperature control devices are inserted into the sheath pipe inserted into the mass concrete at predetermined intervals and insertion lengths. A method for controlling the temperature of mass concrete according to claim 7 or 8.

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