KR20110000986A - Device and method to estimate adiabatic temperature rise of concrete - Google Patents

Abstract

PURPOSE: An apparatus and a method for predicting insulating temperature rise of concrete are provided to predict the hydration calorific value of concrete accurately by correcting heat loss to the temperature rise obtained from a temporary temperature rise test. CONSTITUTION: An apparatus for predicting insulating temperature rise of concrete comprises a case part(110), an insertion part(120), an interior temperature sensor part, an exterior temperature sensor part(140), a transmission part, a control part(160) and a display part(170). The insertion part is built in the case part and applied with a sample. The interior temperature sensor part is provided in the insertion part and measures the temperature of the sample. The exterior temperature sensor part is provided in the case part and measures the exterior temperature. The transmission part is associated with the interior temperature sensor part and the exterior temperature sensor part to transmit the measured temperatures. The control part is associated with the transmission part and analyzes the transmitted temperatures. The display part, in which the control part is built in, indicates the insulation temperature rise of the sample.

Description

DEVICE AND METHOD TO ESTIMATE ADIABATIC TEMPERATURE RISE OF CONCRETE}

The present invention relates to an apparatus and method for estimating concrete insulation temperature rise, and more particularly, to an apparatus and method for estimating concrete insulation temperature rise for analyzing concrete by automatically displaying insulation temperature rise after pouring a concrete sample. will be.

In general, concrete is a hydraulic material, and a large amount of heat (about 120 cal per g of cement) is generated by a chemical reaction during hardening, which is called a heat of hydration.

When the heat of hydration is generated inside the concrete, if the size of the newly cast member is large, there is a temperature difference between the surface of the member where the heat is quickly dissipated to the outside and the inside of the member that has not yet been dissipated. Temperature stress due to thermal stress), and when the newly cast member is in contact with an existing structure, the compressive stress is generated in the entire member at the beginning of the heat of hydration, and then the tensile stress gradually decreases when the temperature of the member starts to decrease. Temperature stress due to external restraint) tends to increase.

When the magnitude of the temperature stress is greater than the tensile strength of the concrete, cracking occurs in the concrete, and the magnitude of the temperature stress induced is closely related to the hydration heating characteristics of the concrete.

The technical structure described above is a background technique for assisting the understanding of the present invention, and does not mean the prior art widely known in the technical field to which the present invention belongs.

The hydration heating characteristics of concrete are most accurately measured through adiabatic temperature rise test (an experiment to measure the temperature rising from the placing temperature with concrete), but the test cost is very expensive, so it is about 1 cubic meter in general sites. It is common to perform a simple adiabatic temperature rise experiment by pouring a model member of.

However, since the simple test is not a complete insulation condition, even if the temperature history of the center of the diarrhea member is measured, there is a problem of underestimating the amount of heat of hydration of concrete as much as heat lost to the outside.

Therefore, there is a need for improvement.

The present invention has been made to improve the above problems, by hydrating calorific value of concrete with an accuracy corresponding to the results that can be obtained in the thermal insulation temperature rise experiment by correcting the heat loss amount obtained from the simple thermal insulation temperature rise experiment The purpose of the present invention is to provide an apparatus and method for estimating concrete insulation temperature rise.

The present invention provides a case portion to achieve the above object; An insertion part embedded in the case part and in which a sample is poured; An internal temperature sensor unit provided at the insertion unit to measure a temperature of the sample; An external temperature sensor unit provided in the case to measure an external temperature; A transmitter for transmitting a temperature measured in association with the internal temperature sensor unit and the external temperature sensor unit; A controller which analyzes a temperature transmitted in association with the transmitter; And a display unit having a built-in control unit and including a display unit for displaying a heat insulation temperature rise value of the sample.

The case part has a lower case one side is opened so that the insertion portion is inserted to form a mounting groove; An upper case covering one side of the lower case; And a coupling part for coupling the lower case and the upper case.

The case portion is characterized in that it comprises a heat insulating material.

The insertion part is inserted into the mounting groove and the insertion cylinder is formed with a cylindrical groove in which the sample is poured into a cylindrical shape on one side opened; And it characterized in that it comprises a handle detachable to the insertion cylinder.

The insertion cylinder is characterized in that it comprises a plastic material.

The handle is characterized in that both ends are screwed to one side end of the insertion cylinder.

The internal temperature sensor unit may include a first internal temperature sensor provided on a central inner surface of the insertion cylinder; A second internal temperature sensor positioned at the center of the insertion tube; And a support for supporting the second internal temperature sensor.

The external temperature sensor is characterized in that it is provided on the outer peripheral surface of the upper case.

The transmission unit is exposed to the outer circumferential surface of the insertion tube and the first internal terminal associated with the first internal temperature sensor; A second inner terminal exposed to an outer circumferential surface of the insertion tube and associated with the support; A first connection terminal in contact with the first internal terminal; A second connection terminal in contact with the second internal terminal; A lower terminal exposed to one end of the lower case; An upper terminal exposed to one end of the upper case and in contact with the lower terminal; A lower transmission cable configured to transmit a signal by connecting one end to the first connection terminal and the second connection terminal and the other end to the lower terminal; And an upper transmission cable which transmits a signal by connecting one end to the external temperature sensor unit and the upper terminal and the other end to the control unit.

The fixing protrusion protruding from the outer circumferential surface of the insertion cylinder is inserted into the fixing groove communicating with the mounting groove, characterized in that the position of the insertion cylinder is fixed.

The control unit is characterized in that for correcting the heat loss amount of the temperature rise of the sample.

And a battery unit for supplying power to the display unit.

In order to achieve the above object, the present invention comprises the steps of measuring the sample temperature of the cylindrical shape; Measuring an external temperature; Estimating a heat loss coefficient; And it provides a concrete thermal insulation temperature increase prediction method comprising the step of displaying the thermal insulation temperature increase predicted through the sample temperature and the external temperature and the heat loss coefficient.

Measuring the sample temperature, characterized in that for measuring the surface and the center temperature of the sample.

The height / diameter ratio of the sample is characterized in that 2 to 3.

The sample is characterized by being in a semi-insulated state surrounded by a heat insulating material.

If the sample exceeds a predetermined date after pouring, the amount of heat of hydration is ignored in estimating the heat loss coefficient.

If the sample is less than a predetermined date after pouring, characterized in that it comprises the step of estimating the heat loss coefficient in the step of estimating the heat loss coefficient.

After calculating the amount of heat of hydration, characterized in that it comprises the step of calculating the additional heat loss for both ends of the sample.

The predetermined date is 5 days in the case of general concrete, 7 days in the case of low heat concrete.

Apparatus and method for estimating concrete insulation temperature rise according to the present invention have the effect of predicting the hydration calorific value of concrete with accuracy corresponding to the result obtained in the insulation temperature rise experiment by correcting the heat loss amount in the temperature rise.

Concrete insulation temperature rise prediction device and method according to the present invention is discarded after the analysis of the sample, it is easy to manage the case part.

Concrete insulation temperature rise prediction device and method according to the present invention is automatically analyzed because the analysis is made on the concrete, there is an effect that can be easily used without expert knowledge.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the apparatus and method for predicting concrete thermal insulation temperature increase according to the present invention. In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to a user's or operator's intention or custom. Therefore, definitions of these terms should be made based on the contents throughout the specification.

1 is an exploded view schematically showing an apparatus for estimating concrete insulation temperature increase according to an embodiment of the present invention, and FIG. 2 is an assembled sectional view of an apparatus for estimating concrete insulation temperature increase according to an embodiment of the present invention.

1 and 2, the concrete thermal insulation temperature increase prediction apparatus 100 according to an embodiment of the present invention, the case unit 110, the insertion unit 120, the internal temperature sensor 130, an external temperature sensor The unit 140, the transmitter 150, the controller 160, and the display unit 170 are provided.

Inserting part 120 is a concrete sample 10 is poured into the case 110, the internal temperature sensor 130 measures the temperature of the sample 10 is poured, the external temperature sensor 140 ) Measures the external temperature.

The transmitter 150 receives a temperature value measured in association with the internal temperature sensor 130 and the external temperature sensor 140. The transmitter 150 transmits the received temperature value in association with the controller 160 to the controller 160.

The controller 160 analyzes the received temperature value to calculate the insulation temperature rise value, and the display unit 170 informs the calculated insulation temperature rise value.

The case part 110 forms an appearance, and the poured sample 10 is embedded therein. The case part 110 includes a heat insulating material to minimize the temperature change of the sample 10. The case part 110 according to the exemplary embodiment of the present invention includes a lower case 111, an upper case 112, and a coupling part 113.

One side of the lower case 111 is opened to form a mounting groove 114. The insertion unit 120 is inserted into the mounting groove 114. The upper case 112 covers one side of the lower case 111. The coupling part 113 couples the lower case 111 and the upper case 112.

Coupling portion 113 is provided in the lower case 111 and the upper case 112 separately and coupled to each other, either one of the engaging projection 113a is formed, the other is rotated by the engaging projection ( It consists of a rotating protrusion 113b which is caught by 113a). In addition, the coupling part 113 may adopt various components capable of coupling or detaching the lower case 111 and the upper case 112 as necessary.

Insertion portion 120 has a container shape in which the sample 10 is poured, it is made of a plastic material to be disposed of and discarded after use and to save manufacturing costs. Insertion portion 120 according to an embodiment of the present invention is provided with an insertion barrel 121 and the handle 122.

Insertion tube 121 is inserted into the mounting groove 114 and the sample 10 is poured into the opened one side. Cylindrical groove 124 is formed in the insertion cylinder 121, the poured sample 10 has a cylindrical shape.

The handle 122 is detachably attached to the insertion tube 121, and the user engages the handle 122 with the insertion tube 121, and then grips the handle 122 to move upward, thereby inserting the insertion tube 121. It is withdrawn from the lower case 111.

The handle 122 is provided with screw fastening protrusions 123 at both ends thereof and is fastened to or separated from the insertion tube 121. In addition, the handle 122 is coupled to the insertion cylinder 121 is rotated, when the lower case 111 and the upper case 112 is coupled, the handle 122 may be inserted into the insertion cylinder 121. In addition, the handle 122 is capable of adopting a variety of shapes to be coupled to or separated from the insertion tube 121.

When the handle 122 is attached or detached to the insertion tube 121, the insertion tube 121 in which the analysis of the sample 10 is completed is discarded, but the handle 122 is reused in the new sample 10 requiring analysis.

The internal temperature sensor unit 130 measures the temperature of the sample 10, and includes a first internal temperature sensor 131, a second internal temperature sensor 132, and a support 133.

The first internal temperature sensor 131 is provided on the central inner surface of the insertion tube 121. The first internal temperature sensor 131 is in contact with the surface of the poured cylindrical sample 10 to measure the temperature of the sample 10.

The second internal temperature sensor 132 is positioned at the center of the insertion tube 121, and the support 133 supports the second internal temperature sensor 132 to be positioned at the center of the insertion tube 121. The second internal temperature sensor 132 is embedded in the poured cylindrical sample 10 to measure the center temperature of the sample 10. At this time, the center of the sample 10 refers to the center of the height and diameter.

The external temperature sensor unit 140 is provided on the outer circumferential surface of the upper case 112 to measure the external temperature.

The transmission unit 150 transmits the temperature value measured through the internal temperature sensor unit 130 and the external temperature sensor unit 140 to the control unit 160. The first internal terminal 151 and the second internal terminal ( 152, a first connection terminal 153, a second connection terminal 154, a lower terminal 155, an upper terminal 156, a lower transmission cable 157, and an upper transmission cable 158 are provided.

The first internal terminal 151 is exposed to the outer circumferential surface of the insertion tube 121 and receives the measured value of the first internal temperature sensor 131 in association with the first internal temperature sensor 131.

The second internal terminal 152 is exposed to the outer circumferential surface of the insertion tube 121, and receives the measured value of the second internal temperature sensor 132 in association with the support 133.

The first connection terminal 153 and the second connection terminal 154 are exposed to the inner surface of the lower case 111 to contact the first internal terminal 151 and the second internal terminal 152, respectively.

The lower terminal 155 is exposed at one end of the lower case 111 and the upper terminal 156 is exposed at one end of the upper case 112. When the lower case 111 and the upper case 112 are coupled to each other, the lower terminal 155 and the upper terminal 156 is in contact with each other.

The lower transmission cable 157 has one end connected to the first connection terminal 153 and the second connection terminal 154 and the other end connected to the lower terminal 155.

Accordingly, the lower transmission cable 157 transmits the values measured by the first internal temperature sensor 131 and the second internal temperature sensor 132 to the lower terminal 155. The lower transmission cable 157 is built in the lower case 111.

The upper transmission cable 158 has one end connected to the external temperature sensor unit 140 and the upper terminal 156 and the other end connected to the control unit 160.

Therefore, the upper transmission cable 158 transmits the external temperature value transmitted through the external temperature sensor unit 140 and the temperature value of the sample 10 transmitted through the internal temperature sensor unit 130 to the controller 160. do.

The fixing protrusion 129 protrudes from the outer circumferential surface of the insertion tube 121, and the fixing groove 119 communicates with the mounting groove 114. At this time, the fixing protrusion 129 is inserted into the fixing groove 119.

Therefore, in the process of inserting the insertion tube 121 into the mounting groove 114 of the lower case 111, the fixing protrusion 129 is inserted into the fixing groove 119 is limited the rotation of the insertion cylinder 121, As a result, the first internal terminal 151 and the first connection terminal 153, the second internal terminal 152 and the second connection terminal 154 remain in contact with each other.

The controller 160 corrects the temperature rise amount and the heat loss amount of the sample 10 to calculate the adiabatic temperature rise value of the sample 10. The controller 160 is preferably embedded in the display unit 170.

The display unit 170 is coupled to the upper case 112 and visually displays the adiabatic temperature rise value calculated by the controller 160. For the convenience of the user, the display unit 170 is provided with a touch screen method, and a controller capable of operating the entire apparatus is provided.

On the other hand, the concrete thermal insulation temperature increase prediction apparatus 100 according to an embodiment of the present invention is further provided with a battery unit 180. The battery unit 180 is embedded in the display unit 170 to supply power to the display unit 170 or the controller 160. By using the battery unit 180, the concrete insulation temperature increase predicting device 100 according to an embodiment of the present invention is portable.

Referring to the use of the concrete insulation temperature increase prediction device according to an embodiment of the present invention.

First, the concrete sample 10 to be analyzed is poured into the insertion cylinder 121 to make a cylindrical shape, and the insertion cylinder 121 including the sample 10 is embedded in the lower case 111.

In this case, the first internal terminal 151 is in contact with the first connection terminal 153, and the second internal terminal 152 is in contact with the second connection terminal 154.

Then, the upper case 112 is positioned at the upper end of the lower case 111, and the lower case 111 and the upper case 112 are coupled to each other through the coupling part 113. At this time, the lower terminal 155 and the upper terminal 156 is in contact.

In the above state, the surface temperature value of the sample 10 measured by the first internal temperature sensor 131 is transmitted to the control unit 160 through the transmission unit 150, and the second internal temperature sensor 132 is transferred to the control unit 160. The center temperature value of the sample 10 measured through the transmission unit 150 is transmitted to the control unit 160. In addition, the external temperature value measured by the external temperature sensor unit 140 is transmitted to the control unit 160 through the transmission unit 150.

Then, the controller 160 estimates the adiabatic temperature rise value of the sample 10 by using the transmitted measured value, and the display unit 170 visualizes it.

On the other hand, when the analysis of the sample 10 is completed, the lower case 111 and the upper case 112 are separated, and then the handle 122 is coupled to the insertion tube 121. Then, the handle 122 is gripped to draw out the insertion tube 121 from the lower case 111 and discarded.

3 is a flowchart illustrating a method for predicting concrete insulation temperature increase according to an embodiment of the present invention, and FIG. 4 is a flowchart illustrating a heat loss coefficient estimating process in a method for predicting concrete insulation temperature increase according to an embodiment of the present invention. to be.

3 and 4, the method of predicting the concrete insulation temperature increase according to an embodiment of the present invention is as follows. At this time, it will be described with reference to the concrete heat insulation temperature increase amount prediction device 100 shown in FIG.

First, the temperature of the cylindrical sample 10 is measured through the internal temperature sensor unit 130 (S10), and the external temperature is measured through the external temperature sensor unit 140 (S20).

The value measured by the internal temperature sensor unit 130 and the external temperature sensor unit 140 is transmitted to the control unit 160 through the transmission unit 150, the control unit 160 using the transmitted measurement value heat loss The coefficient is estimated (S30).

In this case, the values measured through the internal temperature sensor unit 130 and the external temperature sensor unit 140 are transmitted to the controller 160 regardless of the order.

The controller 160 estimates the heat loss coefficient to predict the adiabatic temperature rise value of the sample 10, and the display unit 170 displays the information and informs the user (S40).

When the temperature of the sample 10 is measured, the surface and the center temperature of the sample 10 are measured through the first internal temperature sensor 131 and the second internal temperature sensor 132.

At this time, the insertion cylinder 121 is designed such that the height / diameter ratio of the sample 10 is 2 to 3, and the insertion cylinder 121 is surrounded by a heat insulating material so as to suppress heat loss to maintain a quasi-insulation state.

Meanwhile, the method of estimating the heat loss coefficient varies according to the time the sample 10 is poured. Because, the sample 10 hydration reaction can be considered that more than 98% of the total reaction is completed after a predetermined time after pouring.

It is determined whether the sample 10 exceeds a predetermined date after the pouring (S31), and when the sample 10 exceeds the predetermined date after the pouring, the hydration calorific value of the sample 10 is ignored (S32).

On the other hand, it is determined whether the sample 10 exceeds a predetermined date after being poured (S31), and when the sample 10 is less than a predetermined date after being poured, the amount of hydration heat of the sample 10 is calculated (S33).

Further, after calculating the hydration calorific value of the sample 10, the additional heat loss for the upper and lower ends of the cylindrical sample 10 is calculated (S34).

At this time, the predetermined date is variable according to the type of concrete, 5 days in the case of general concrete, 7 days in the case of low heat concrete.

5 is a view showing the results of the parameter analysis in the concrete thermal insulation temperature rise prediction theory according to an embodiment of the present invention, Figure 6 is a sample inside assumed in the concrete thermal insulation temperature rise prediction theory according to an embodiment of the present invention Figure 7 is a view showing the temperature distribution of, Figure 7 is a view showing the temperature history inside the sample in the concrete thermal insulation temperature rise prediction theory according to an embodiment of the present invention, Figure 8 is a concrete according to an embodiment of the present invention In the thermal insulation temperature rise prediction theory is a view showing the thermal insulation temperature rise prediction result before the additional heat loss correction, Figure 9 is a thermal insulation temperature rise prediction result after the additional heat loss correction in the concrete thermal insulation temperature rise prediction theory according to an embodiment of the present invention Figure is a diagram.

Hereinafter, the theory that enables the prediction of concrete insulation temperature rise is as follows.

In the case of the simple adiabatic temperature rise test, the temperature inside the concrete is changed by the difference between the heat generated by the heat of hydration of the concrete and the heat lost to the outside. If this is expressed as an expression, it is as follows.

Formula (1)

는 콘크리트의 밀도,

는 콘크리트의 비열,

는 시간,

는 콘크리트 내부의 평균적인 온도변화로서 식(2)와 같이 정의되며,

는 콘크리트의 부피,

는 콘크리트 내부의 열량 변화,

는 수화열로 인해 발생되는 열량,

은 외부로 손실되는 열량이다.here,

Is the density of concrete,

Specific heat of concrete,

Time,

Is the average temperature change inside the concrete, defined as in Eq. (2),

Is the volume of concrete,

Changes in calories inside the concrete,

Is the heat generated by the heat of hydration,

Is the amount of heat lost to the outside.

Equation (2)

는 콘크리트 내부의 위치를 나타내는 좌표 변수,

는 콘크리트의 초기온도(즉,

)이다.here,

Is a coordinate variable representing the location inside the concrete,

Is the initial temperature of the concrete (i.e.

)to be.

The amount of heat lost to the outside is generally known to be proportional to the difference between the outside air temperature and the concrete surface temperature. The proportionality constant is called the convection coefficient.

Formula (3)

는 대류계수,

는 시간

일 때의 외기온도,

는 시간

일 때 콘크리트의 표면온도,

는 열손실 면적,

는 열전도계수,

은 열손실면에 수직한 방향에 대한 콘크리트 표면의 온도 기울기이다.here,

Is the convection coefficient,

Time

Outside temperature when

Time

Surface temperature of concrete when

Is the heat loss area,

Is the thermal conductivity,

Is the temperature gradient of the concrete surface with respect to the direction perpendicular to the heat loss plane.

는 생략).By substituting Eq. (3) into Eq. (1), the following relational expression can be obtained.

Is omitted).

Formula (4)

는 시간

의 단열온도상승량이다. 만약, 시간 및 위치에 관계없이

가 일정하고, 특정 시간에 콘크리트의 열손실면에서 측정한

값이 위치에 관계없이 일정하다면 식(4)를 다음과 같이 단순화할 수 있다.here,

Time

This is the increase in insulation temperature. If, regardless of time and location

Constant, measured in terms of heat loss of concrete at specific times

If the value is constant regardless of position, Equation (4) can be simplified as:

Formula (5)

는 열손실계수이다. here,

Is the heat loss coefficient.

In other words, knowing the temperature distribution, the heat loss coefficient (or convection coefficient), and the outside temperature inside the concrete, it is possible to estimate the thermal insulation temperature rise of the concrete using equations (4) and (5).

에 대한 콘크리트 실험체 내부의 온도분포

가 필요한데, 이는 시간

에 실험체 내부 특정 지점의 온도를 측정하고 그 결과를 외삽(extrapolate)하여 추정한다. Random time to calculate the average temperature change inside the concrete using equation (2)

Temperature distribution inside the concrete specimen for

Is needed, which means

The temperature is measured at a specific point within the test specimen and extrapolated to the result.

를 단순화할수록 이를 외삽추정하기 위한 온도 측정 지점의 개수가 감소하여 실험비용을 절감할 수 있는 이점이 있다. That is, the temperature distribution function

Simplification of the method reduces the cost of experiment by reducing the number of temperature measuring points for extrapolating this.

로 표현됨). Therefore, we propose a technique that can simplify the temperature distribution inside the test body in one dimension by appropriately adjusting the shape and thermal insulation conditions of the test object.

Expressed as

First, the shape of the concrete specimen proposed in the present invention for the simplification of the temperature distribution is a cylinder, and this type of specimen has a heat loss condition close to one dimension near the center (that is, the temperature distribution near the center is the center of the specimen). As a function of distance measured horizontally in.

)가 폭(

)보다 충분히 크거나 위아래 면의 단열성능이 옆면보다 상대적으로 매우 우수한 경우에는 실험에 필요한 기간동안 원기둥 중심부 부근의 온도분포를 1차원조건으로 유지시킬 수 있다. However, unless the top and bottom surfaces of the cylinder are not completely insulated, there is a limit to the loss of heat in three-dimensional form near the top and bottom surfaces.

) Width (

In the case of sufficiently larger than) or superior thermal insulation performance of the upper and lower sides, the temperature distribution near the center of the cylinder can be maintained in one-dimensional conditions for the period required for the experiment.

가 너무 크면 불필요하게 실험체의 크기가 커져서 재료가 낭비됨은 물론 실험체의 취급도 어려워지는 단점이 있으므로,

비를 2~3 수준으로 유지하 면서 위아래 면의 단열성능을 조절하여 중앙부에서 1차원의 열손실 조건을 모사할 수 있는 방법을 제시하고자 한다. At this time,

Is too large, the size of the test object is unnecessarily large, which wastes material and makes handling of the test object difficult.

We will suggest a method to simulate the 1-dimensional heat loss condition in the center by controlling the insulation performance of the upper and lower surfaces while maintaining the ratio at 2 ~ 3 levels.

For this, parametric analysis was performed using the finite element program, and the input values for each analysis case are shown in Table 1 below.

TABLE 1

가 대략 0.5이고, 2cm의 스티로폼을 설치하는 경우

가 대략 2이다.When installing styrofoam with a thickness of 8 cm on the concrete surface in Table 1

Is approximately 0.5 and 2 cm styrofoam is installed

Is approximately 2.

가 더 큰 C의 경우가 1차원 열소산 조건에 더 가까움을 확인할 수 있다. Figure 5 shows the results of the analysis, showing the temperature history of the center of the specimen for each case. Comparing the analysis results of A and C

It can be seen that the larger C is closer to the one-dimensional heat dissipation condition.

에 무관하게 거의 동일한 (1차원 조건에 가까운) 온도이력 결과가 나타남을 확인할 수 있다.Comparing B and D with A and C, the convection coefficients of the upper and lower sides were reduced to 25% of the sides, indicating that the heat dissipation conditions in the center of the specimen were simulated almost similar to the one-dimensional conditions. Decreasing the convection coefficient

Irrespective of this, we can see that almost identical temperature history results (near one-dimensional conditions) are shown.

를 증가시키기 보다는 위아래면의 단열성능을 옆면에 비해 현저히 증가시키는 것이 보다 용이하게 실험체 내부의 온도분포를 단순화하는 방법임을 알 수 있다.Therefore, taking into account that the size and weight of the experimental apparatus mainly depends on the size of the concrete specimen,

Rather than increasing the thermal insulation performance of the upper and lower surfaces than the side can be seen to simplify the temperature distribution inside the specimen more easily.

에 대한 콘크리트 내부의 온도분포를 하나의 변수,

(콘크리트의 열손실면으로부터 이에 수직한 방향으로 측정된 거리)로 표현할 수 있다. 온도분포를 모사하기 위해 사용되는 수식은 어떤 형태를 사용하여도 무방하나, 여기서는 식(6)과 같이 가장 단순한 형태의 수식인 2차 다항식을 사용하였다.Any time if the heat loss condition of the concrete specimen can be assumed in one dimension

The temperature distribution inside the concrete for a single variable,

It can be expressed as (the distance measured in the direction perpendicular to the heat loss surface of the concrete). The formula used to simulate the temperature distribution can be used in any form, but here, the second order polynomial, which is the simplest form of equation, is used as shown in equation (6).

Formula (6)

,

,

은 온도분포를 모사하기 위한 상수이며, 경계조건과 실험체에서 직접 측정된 온도값을 사용하여 결정된다. 식(6)의 경우, 미지수가 3개이므로 3가지 지점에 대한 온도 측정 자료가 필요하다. here,

,

,

Is a constant to simulate the temperature distribution and is determined using the boundary conditions and the temperature values measured directly on the specimen. In Eq. (6), three unknowns are required, so temperature measurement data for three points are needed.

에 각 위치에서 측정된 온도를

,

,

로 표현하였다. In this case, it is assumed that the three temperatures of the concrete center, surface temperature, and outside temperature are measured.

Temperature measured at each location

,

,

Expressed as

는 열손실면에 수직한 방향으로 측정된 거리,

는 실험체의 지름을 나타낸다. Figure 6 shows the temperature distribution inside the concrete simulated using equation (6).

Is the distance measured in the direction perpendicular to the heat loss plane,

Represents the diameter of the test body.

인 지점은 콘크리트 시편의 정중앙을 의미하며, 콘크리트 내부의 온도분포는

지점을 중심으로 축대칭 분포가 된다.therefore Is the heat loss surface,

The phosphorus point means the center of the concrete specimen, and the temperature distribution inside the concrete

There is an axisymmetric distribution around the point.

가 다음과 같은 관계를 만족하여야 함을 알 수 있다.From the symmetry between the given temperature measurement and the temperature distribution in the concrete

It can be seen that the following relationship must be satisfied.

,

,

Formula (7)

,

,

,

,

을 구할 수 있다. Substituting Eq. (6) into Eq. (7),

,

,

Can be obtained.

,

,

Formula (8)

,

,

Finally, by substituting the temperature distribution of equation (6) into equations (2) and (5), the following relation can be derived.

Formula (9)

Formula (10)

Equations (9) and (10) are simplified adiabatic temperature prediction equations for the case where the temperature distribution inside the concrete is expressed as a second order polynomial such as Eq. (6). have.

However, whatever type of temperature distribution equation is used, the above procedure can be used to derive a simplified adiabatic temperature prediction equation.

일(일반콘크리트의 경우임. 저발열 콘크리트의 경우 7일 이상)이 되면

으로 가정할 수 있으며, 이를 식(5)에 적용하면 다음과 같은 관계식을 구할 수 있다.The hydration of concrete can be considered to have been completed more than 98% of the total reaction after 5 days of casting. In other words,

Work (in the case of general concrete, 7 days or more for low heat concrete)

It can be assumed that, if applied to Eq. (5), the following relation can be obtained.

Formula (11)

를 계산할 수 있다.Using Equation (11), the heat loss coefficient of the simple adiabatic temperature rise experiment using the thermometer results after the hydration of the concrete is almost complete.

Can be calculated.

From the boundary condition of the concrete heat loss surface shown in equation (3) and the relationship between the convection coefficient and heat loss coefficient shown in equation (5), the following equation can be derived.

Formula (12)

를 계산할 수 있다. 예를 들어 식(6)과 같은 온도분포 함수를 사용하는 경우, 식(12)를 다음과 같이 정리할 수 있다.In other words, if only the temperature distribution function inside the concrete is defined, the convection coefficient can be estimated using the derivative value, and finally the heat loss coefficient from this.

Can be calculated. For example, in the case of using a temperature distribution function such as Equation (6), Equation (12) can be summarized as follows.

Formula (13)

Equation (10) is derived assuming no heat loss at all on the upper and lower sides of the test body. Equations (12) and (13) basically consider only the rate of heat loss through the side of the test body. ), Since the heat loss over the entire area of the test body is already taken into account, it is not necessary to apply an additional heat loss correction factor).

However, even if the specimen is configured as close to the one-dimensional heat loss condition as possible, a small amount of heat loss may occur to the top and bottom surfaces. This additional heat loss can be considered simply by multiplying the estimated basic heat loss coefficient by the additional heat loss correction factor such as Eq. (14).

Formula (14)

는 추가 열손실 보정계수,

는 윗면의 대류계수,

는 윗면의 면적,

는 아랫면의 대류계수,

는 아랫면의 면적,

는 옆면의 대류계수,

는 옆면의 면적이다.here,

Is the additional heat loss correction factor,

Is the convection coefficient on the top,

Is the area of the top surface,

Is the convection coefficient at the bottom,

Is the area of the underside,

Is the convection coefficient on the side,

Is the area of the side surface.

<Application example>

Here, the validity of the proposed procedure is applied to the interpretation of the sign language model.

)과 비교하였다. In order to evaluate the errors according to the actual experimental conditions, analyze the ref condition, B condition, and D condition of Table 1, and calculate the adiabatic temperature rise estimated from the result.

).

에 일교차 12로 변하는 것으로 설정하여 수화열 해석을 수행하였다.At this time, the outside temperature is not constant so that the actual experimental conditions can be considered.

On a cross 12 Hydration heat analysis was performed by changing to.

,

를 도시한 것이다. 실험체의 단열조건이 좋지 않은 편이기 때문에(옆면의

) 외기온도 변화에 따라 실험체 내부의 온도가 매일

정도씩 변하는 것을 확인할 수 있다. 7 is an example of a sign language analysis result for a ref condition.

,

It is shown. Because the insulation condition of the specimen is not good (the side

) As the outside temperature changes, the temperature inside the test object

You can see the change by degree.

Figure 8 shows the adiabatic temperature rise predicted by applying the procedure proposed in the present invention to the analysis results for each condition, and shows the result before considering the additional heat loss correction coefficient.

Comparing the predicted results, the predicted value and the input value are almost identical in the case of ref, which is a complete one-dimensional heat loss condition, but the predicted value is input by the amount of heat lost to the top and bottom surfaces in the case of similar one-dimensional heat loss conditions, B and C. It can be seen that they are about 5.8 and 3.3% smaller than the values.

9 shows the result of correcting such an error using an additional heat loss correction coefficient. After the correction, it can be confirmed that the prediction result is very similar to the analysis input value for all conditions, and through this, the validity of the idea presented in the present invention can be verified.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and those skilled in the art to which the art belongs can make various modifications and other equivalent embodiments therefrom. I will understand.

Therefore, the true technical protection scope of the present invention will be defined by the claims below.

1 is an exploded view schematically showing an apparatus for predicting concrete thermal insulation temperature increase according to an embodiment of the present invention.

2 is an assembled cross-sectional view of the concrete heat insulation temperature increase prediction apparatus according to an embodiment of the present invention.

3 is a flowchart illustrating a method for predicting concrete thermal insulation temperature increase according to an embodiment of the present invention.

4 is a flowchart illustrating a heat loss coefficient estimating process in the method of predicting the thermal insulation temperature rise according to an embodiment of the present invention.

5 is a diagram showing the results of the parameter analysis in the concrete thermal insulation temperature rise prediction theory according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating a temperature distribution inside a sample assumed in a concrete insulation temperature increase prediction theory according to an embodiment of the present invention.

7 is a view showing the temperature history inside the sample in the concrete thermal insulation temperature increase prediction theory according to an embodiment of the present invention.

8 is a view showing a heat insulation temperature rise prediction result before the additional heat loss correction in the concrete heat insulation temperature rise prediction theory according to an embodiment of the present invention.

9 is a view showing a heat insulation temperature rise prediction result after the additional heat loss correction in the concrete heat insulation temperature rise prediction theory according to an embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

110: case portion 111: lower case

112: upper case 120: insertion portion

121: insertion tube 122: handle

130: internal temperature sensor unit 140: external temperature sensor unit

150: transmission unit 160: control unit

170: display unit 180: battery unit

Claims (20)

A case part; An insertion part embedded in the case part and in which a sample is poured; An internal temperature sensor unit provided at the insertion unit to measure a temperature of the sample; An external temperature sensor unit provided in the case to measure an external temperature; A transmitter for transmitting a temperature measured in association with the internal temperature sensor unit and the external temperature sensor unit; A controller which analyzes a temperature transmitted in association with the transmitter; And The control unit has a built-in concrete insulation temperature rise prediction device, characterized in that it comprises a display unit for displaying the heat insulation temperature rise value of the sample. The method of claim 1, wherein the case portion A lower case in which one side is opened so that the insertion part is inserted and a mounting groove is formed; An upper case covering one side of the lower case; And Concrete insulation temperature increase prediction device comprising a coupling unit for coupling the lower case and the upper case. The method according to claim 1 or 2, Concrete case thermal insulation temperature increase prediction device, characterized in that the case comprises a heat insulating material. The method of claim 2, wherein the insertion portion An insertion cylinder inserted into the mounting groove and having a cylindrical groove in which a sample is cast in a cylindrical shape with one side opened; And Concrete insulation temperature increase prediction device comprising a handle detachably attached to the insertion cylinder. The method of claim 4, wherein The insertion cylinder is a concrete insulation temperature increase prediction device, characterized in that comprises a plastic material. The method of claim 4, wherein The handle is a concrete heat insulating temperature rise prediction device, characterized in that both ends are screwed to one end of the insertion cylinder. The method of claim 4, wherein the internal temperature sensor unit A first internal temperature sensor provided at a central inner surface of the insertion tube; A second internal temperature sensor positioned at the center of the insertion tube; And Concrete insulation temperature increase prediction device comprising a support for supporting the second internal temperature sensor. The method of claim 2, wherein the external temperature sensor unit Concrete insulation temperature increase prediction device, characterized in that provided on the outer peripheral surface of the upper case. The method of claim 7 or 8, wherein the transmission unit A first internal terminal exposed to an outer circumferential surface of the insertion tube and associated with the first internal temperature sensor; A second inner terminal exposed to an outer circumferential surface of the insertion tube and associated with the support; A first connection terminal in contact with the first internal terminal; A second connection terminal in contact with the second internal terminal; A lower terminal exposed to one end of the lower case; An upper terminal exposed to one end of the upper case and in contact with the lower terminal; A lower transmission cable configured to transmit a signal by connecting one end to the first connection terminal and the second connection terminal and the other end to the lower terminal; And One end of the external temperature sensor unit and the upper terminal is connected to the other end is connected to the other end is connected to the control unit, characterized in that it comprises an upper transmission cable for transmitting a signal. The method of claim 9, Precipitating projection projecting from the outer circumferential surface of the insertion cylinder is inserted into the fixing groove communicating with the mounting groove is concrete insulation temperature rise prediction device, characterized in that the position of the insertion cylinder is fixed. The method of claim 1, The control unit predicts the thermal insulation temperature rise of the concrete, characterized in that for correcting the heat loss amount to the temperature rise of the sample. The method of claim 1, Concrete insulation temperature increase prediction device further comprises a battery unit for supplying power to the display unit. Measuring a sample temperature in a cylindrical shape; Measuring an external temperature; Estimating a heat loss coefficient; And And displaying the insulation temperature increase predicted through the sample temperature, the external temperature, and the heat loss coefficient. The method of claim 13, Measuring the sample temperature, The method of predicting the concrete insulation temperature increase, characterized in that for measuring the surface and the center temperature of the sample. The method of claim 13, The height / diameter ratio of the sample is a concrete insulation temperature increase prediction method, characterized in that 2 to 3. The method of claim 13, The sample is a method of predicting the temperature increase of concrete insulation, characterized in that the insulation is surrounded by a heat insulating material. The method of claim 13, When the sample is more than a predetermined date after pouring, the method of predicting the heat insulation temperature rise of concrete, characterized in that the step of ignoring the hydration calorific value in estimating the heat loss coefficient. The method of claim 13, If the sample is less than a predetermined date after the pouring, the method of estimating the heat insulation coefficient of concrete, characterized in that it comprises the step of calculating the calorific value of heat insulation concrete. The method of claim 18, And calculating additional heat loss for both ends of the sample after calculating the amount of heat of hydration. The method of claim 17 or 18, The predetermined date is 5 days in the case of ordinary concrete, 7 days in the case of low heat concrete concrete insulation temperature rise prediction method.

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