KR101580864B1 - Method and apparatus for measuring adiabatic temperature-rise of concrete - Google Patents

Abstract

The present invention relates to a method and an apparatus for measuring the amount of increase in the amount of increase in the amount of heat of concrete, .
According to the present invention, it is possible to easily measure the amount of rise in the adiabatic temperature of the concrete, which can be easily used in actual use sites, while improving the accuracy of the conventional apparatus.

Description

METHOD AND APPARATUS FOR MEASURING ADIABATIC TEMPERATURE-RISE OF CONCRETE BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a method and an apparatus for measuring the amount of increase in the amount of increase in the amount of heat of concrete, .

When cement reacts with water, about 120 cal of heat is generated per gram by the exothermic chemical reaction, which is called hydration heat. Heat of hydration raises the temperature inside the concrete and causes the accompanying volume change. When this volume change is restrained, thermal stress occurs in the concrete structure. This phenomenon is evident in a mass concrete structure with a thick concrete member, and it causes tensile stresses exceeding the tensile strength of the concrete, thereby becoming a main cause of the early cracks of the concrete. Since the temperature stress is closely related to the concrete water hydration heat generation, that is, the possibility of the concrete cracking due to the increase in the initial adiabatic temperature rise and the reaction rate, the precise prediction of the temperature stress should accurately predict the hydration heat of concrete.

The method of measuring hydration heat of concrete is most commonly used for measuring the heat of cement hydration using microcalorimetry and the method for ascending heat of concrete. The cement hydration heat method using microcalorimeter measures the amount of heat generated after reacting cement and water at constant temperature condition. This method is disadvantageous in predicting the temperature rise of mass concrete because the sample temperature is neglected. On the other hand, the adiabatic temperature rise test method is a method to measure the temperature rise amount generated by keeping the inserted concrete in an adiabatic state, and it can relatively accurately measure the hydration heat characteristic of concrete. However, since the test cost is high, In fact.

The existing simple adiabatic temperature rise measuring device has developed a semi-adiabatic condition test method, but since the outside temperature condition should be constant at 20 ° C and the heat loss correction method is simply used, the temperature history and the ambient condition of the concrete There is a limit to ignore the reaction rate. Also, the temperature history of the temperature change state has a problem in that a delayed portion and a trembling portion occur in the conventional correction method.

KR 10-1151668 B1

Hyun. J. Y. "Development of Experimental Equipment for Thermal Stress in Mass Concrete", M. S. Thesis, Korea Advanced Institute of Science and Technology, 2000. pp. 14-18

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to enable easy use in actual use sites, and at the same time to enable the measurement of the increase in the adiabatic temperature rise of concrete, .

에 의해 산출되고, 여기서 t는 표준양생의 재령, t_ec는 양생온도의 등가재령, t_ea는 열손실량 보정을 통한 단열온도상승곡선의 등가재령, t_er은 반응속도를 보정한 재령이며,상기 t_er을 단열온도상승 곡선의 시간축 값에 적용한다.In order to achieve the above object, the present invention provides a method for measuring an increase in the adiabatic temperature rise of concrete, comprising the steps of: (a) measuring a concrete sample temperature in a concrete adiabatic temperature rise measurement device, Measuring a temperature outside the apparatus; (b) calculating a heat loss coefficient of the concrete adiabatic temperature rise measurement device; (c) performing a heat loss correction of the concrete adiabatic temperature rise measurement device; (d) correcting the hydration reaction rate; And (e) calculating a predicted value of the adiabatic temperature rise amount of the concrete sample, wherein in the step (d)

Where t is the age of the standard curing, t _ec is the equivalent age of the curing temperature, t _ea is the equivalent age of the adiabatic temperature rise curve through heat loss correction, and t _er is the age corrected for the reaction rate, t _er is applied to the time base value of the adiabatic temperature rise curve.

에 의해 산출될 수 있고,The heat loss coefficient,

Lt; / RTI >

는 콘크리트 내부의 평균적인 온도 변화,

는 시간 t일 때 콘크리트의 표면 온도,

는 시간 t일 때 콘크리트의 외기 온도이다.Where α (t) is the heat loss coefficient of the device for measuring the temperature rise of concrete,

The average temperature change in the concrete,

Is the surface temperature of the concrete at time t,

Is the ambient temperature of the concrete at time t.

delete

The method may further include a step of calculating a delay time due to the wall thickness of the concrete adiabatic temperature rise amount measuring apparatus before the step (c) when the external temperature is in a temperature change state, can be applied to the heat loss correction of (c).

에 의해 산출될 수 있고,The delay time,

Lt; / RTI >

Where t _dh is the delay time (hour) and h _a is the heat loss coefficient.

The method according to any one of claims 1 to 3, wherein when the external temperature is in a state of a temperature change, the average value of the rising and falling points of the concrete temperature fluctuation Quot ;, < / RTI >
According to another aspect of the present invention, there is provided an apparatus for measuring an increase in the adiabatic temperature of concrete, comprising: a sample portion into which a concrete sample to be measured is injected; An internal temperature sensor for measuring the temperature of the concrete sample in the apparatus for measuring the increase of the adiabatic temperature of the concrete; An external temperature sensor unit for measuring the temperature of the outside of the apparatus for measuring the increase of the adiabatic temperature of the concrete; And a predicted value of an adiabatic temperature rise amount calculation unit for calculating a predicted value of the adiabatic temperature rise amount of the concrete sample, wherein the predicted value of the adiabatic temperature rise amount calculation unit comprises: a heat loss coefficient calculation module for calculating a heat loss coefficient of the concrete heat insulation temperature rise amount measurement device; A heat loss correction module for correcting the additional heat loss amount to the upper and lower surfaces to obtain a heat loss amount; A reaction rate correction module for correcting a hydration reaction rate due to a difference in ambient temperature; An adiabatic temperature rise amount predicted value calculating module for calculating a predicted value of the adiabatic temperature rise amount to which the heat loss correction and the reaction rate correction are applied; And a controller for controlling each module of the predicted value of the adiabatic temperature rise amount to perform a series of processes related to the predicted value of the adiabatic temperature rise amount,

Where t is the age of the standard curing, t _ec is the equivalent age of the curing temperature, t _ea is the equivalent age of the adiabatic temperature rise curve through heat loss correction, and t _er is the age corrected for the reaction rate, t _er is applied to the time base value of the adiabatic temperature rise curve.

The predicted value of the adiabatic temperature rise amount is calculated by calculating the delay time according to the thickness of the wall where the concrete insulation adiabatic temperature rise amount measuring apparatus 100 is in contact with the outside air to thereby correct the heat loss And a delay time correction module for performing the delay time correction module.

The predicted value of the adiabatic temperature rise amount is calculated as an average value of rising and falling points (hereinafter referred to as 'temperature moving average') with respect to the fluctuation of the concrete temperature, which is repeatedly rising and falling, And a temperature moving average calculating module for calculating a temperature moving average calculating module.

In the case of ambient temperature change, the predicted value of the adiabatic temperature rise amount calculation module can calculate the predicted value of the adiabatic temperature rise amount by further applying the heat loss correction using the delay time correction and the reaction rate correction using the moving average of the temperature.

The concrete heat insulating temperature rise measuring apparatus may further include a display unit for displaying data on the process of calculating the predicted value of the adiabatic temperature rise amount and the calculated predicted value of the adiabatic temperature rise amount and providing an interface with which the user can control in the process.

According to the present invention, it is possible to easily measure the amount of increase in the adiabatic temperature rise of concrete, which is improved in accuracy compared with the conventional device, while allowing easy use in actual use sites.

1 is a conceptual diagram of an apparatus for measuring a rise in the adiabatic temperature of concrete according to the present invention.
FIG. 2 is a graph showing the temperature distribution in the concrete placed in the apparatus for measuring the temperature rise of concrete. FIG.
3 is a flowchart of a method for measuring a rise in the adiabatic temperature of concrete in an apparatus for measuring a rise in the adiabatic temperature of concrete according to the present invention.
Fig. 4 is a diagram showing a method for determining the apparent activation energy of concrete in a thermal curing. Fig.
5 is a diagram showing a relationship between a delay time and a heat loss coefficient;
FIG. 6 is a view comparing temperature histories when heat loss correction and delay time correction are performed using only a heat loss correction only and a moving average in an ambient temperature change state; FIG.
7 is a view showing a configuration of a concrete heat insulation temperature rise amount calculation unit in a concrete insulation heat rise amount measurement apparatus according to the present invention.
8 is a photograph of a concrete heat insulation temperature rise tester.
9 is a view showing an adiabatic temperature rise curve.
10 is a view showing a verification test apparatus of an apparatus for measuring the amount of elevated amount of concrete adiabatic temperature according to the present invention.
11 is a view showing a temperature history due to heat loss correction under ambient air temperature conditions.
12 is a view for comparing the predicted value of the adiabatic temperature rise and the concrete adiabatic temperature rise amount measurement device in the open-air constant temperature condition.
13 is a view showing a temperature history due to heat loss correction under ambient temperature condition.
14 is a diagram showing a heat loss correction considering the delay time and the moving average in the ambient temperature change condition;
FIG. 15 is a view showing the results of correcting heat loss, delay time, and reaction speed under ambient temperature condition. FIG.
Fig. 16 is a graph showing an error range of an actual adiabatic temperature rise amount and a resultant value obtained by the concrete adiabatic temperature rise amount measurement according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined. Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

FIG. 1 is a conceptual diagram of an apparatus 100 for measuring a rise in the adiabatic temperature of a concrete according to the present invention, and FIG. 2 is a graph showing a temperature distribution in a concrete placed in the apparatus for measuring an increase in the adiabatic temperature of a concrete 100.

An internal temperature sensor 120 for measuring the temperature of the concrete sample in the apparatus for measuring the increase in the adiabatic temperature rise of the concrete, an internal temperature sensor 120 for measuring the increase in the adiabatic temperature of the concrete, An external temperature sensor 130 for measuring the temperature outside the measuring device, data for calculating the predicted value of the adiabatic temperature rise amount, and predicted value of the calculated adiabatic temperature rise amount, and provides an interface that can be controlled by the user A display unit 140, and an adiabatic temperature rise prediction amount calculating unit 150 for calculating a predicted value of the adiabatic temperature rise amount of the concrete sample. However, in FIG. 1, the predicted value of the adiabatic temperature rise amount calculation unit 150 is not shown, and its configuration is shown in FIG.

The reason why the conceptual diagram is a cylindrical shape is to simulate the heat loss process as an axisymmetric condition as shown in FIG. 2 and to use a widely used columnar specimen. When fabricated according to the conceptual diagram, the size of the device heat loss coefficient is the most important issue. This is because if the heat loss coefficient is large even if the heat of hydration of concrete occurs, the temperature history of the concrete changes greatly according to the outside temperature. Therefore, when manufacturing the measuring device, a high-performance insulating material was inserted between the thermosensitive material and the polyethylene material to maintain the condition close to the adiabatic condition.

There is a problem that the heat loss coefficient of the apparatus can be changed depending on the presence or absence of an internal air layer. In order to solve this problem, the influence of the humidity was excluded by inserting rubber on the upper and lower devices so that there is no air layer inside. In addition, as an embodiment, a disposable concrete mold having a diameter of 100 mm and a height of 200 mm can be inserted into the measuring apparatus so as to be efficiently used in an actual construction site.

In order to calibrate the heat loss, the outside temperature and the inside and outside temperature of the concrete should be measured by the temperature sensor. To this end, a small data logger capable of attaching and detaching to the top of the measuring device was made to connect the display and the temperature sensor. Also, the measured temperature value is calculated by using a module for analyzing and processing the heat loss, the delay time and the reaction speed of the concrete exothermic reaction in real time (hereinafter referred to as a 'predicted value of the adiabatic temperature rise amount calculation control part'), . In one embodiment, the size of the adiabatic temperature rise measurement device according to the present invention is cylindrical with a diameter of 240 mm and a height of 370 mm.

FIG. 3 is a flowchart of a method for measuring the amount of increase in the adiabatic temperature of concrete in the apparatus 100 for measuring an elevated amount of concrete adiabatic temperature according to the present invention.

First, the temperature of the concrete sample to be measured and the outside air temperature outside the concrete heat insulation temperature rise measuring device 100 are measured (S310 and S320), and the heat loss coefficient of the concrete heat insulation temperature rise measuring device 100 is measured S330).

Thereafter, the amount of heat loss of the concrete adiabatic temperature rise amount measuring apparatus 100 is corrected (S352, S361). However, the outdoor air temperature state is checked in step S340. If the outdoor air temperature is in the fluctuating temperature state, the delay time is corrected before the heat loss correction (S351).

If the outside air temperature is maintained at a constant temperature, the heat loss correcting step is performed (S361) and the calorific value (reaction speed) according to the external temperature is corrected (S362).

However, if the outside air is in a state of temperature change, the heat amount correction (S352) is followed by a moving average of the rising and falling temperature state (S353), and then the calorific value (reaction speed) according to the external temperature is corrected (S354).

In step S370, the amount of increase in the adiabatic temperature of the concrete is measured by the apparatus 100 for measuring the amount of elevated temperature of the concrete.

Hereinafter, each of the above-described steps will be described in more detail with reference to FIGS. 4 to 6. FIG.

4 is a view showing a method of determining the apparent activation energy of concrete in the curing of the temperature change, FIG. 5 is a view showing the relationship between the delay time and the heat loss coefficient, FIG. And comparing the temperature history when the heat loss correction and the delay time correction are performed using the moving average in the ambient temperature change state.

First, the heat loss coefficient measurement (S330) will be described.

The hydration reaction of the concrete is completed at 98 percent of the total reaction after 5 days of pouring. That is, it can be assumed that there is no hydration heat amount when t> 5 days for general concrete and t> 7 days for low-heat concrete. The heat loss of the apparatus 100 for measuring the thermal insulation rise of the concrete occurs through a complex process of conduction, convection and radiation in the measuring apparatus, but this is defined as one heat loss coefficient. The process of calculating the heat loss coefficient of the concrete heat insulation temperature rise measuring apparatus 100 is shown in Equation (1).

는 콘크리트 내부의 평균적인 온도 변화,

는 시간 t일 때 콘크리트의 표면 온도,

는 시간 t일 때 콘크리트의 외기 온도이다. 수학식 1을 이용하여 측정 장치의 열손실계수를 구하는 방법은 두 가지가 있다. 첫째로, 콘크리트의 수화반응이 거의 완료된 이후의 온도 계측 결과를 이용하는 것이다. 두번째는 수화반응이 없는 물을 측정 장치 내부에 넣고 온도 계측을 하여 열손실계수를 구하는 것이다.Where α (t) is the heat loss coefficient of the simple adiabatic temperature rise measurement device,

The average temperature change in the concrete,

Is the surface temperature of the concrete at time t,

Is the ambient temperature of the concrete at time t. There are two methods of obtaining the heat loss coefficient of the measuring apparatus using Equation (1). First, the result of the temperature measurement after the hydration reaction of the concrete is almost completed is used. The second is to measure the heat loss coefficient by inserting water without hydration reaction inside the measuring device and measuring the temperature.

In order to accurately estimate the adiabatic temperature rise of the measuring device, the correct heat loss coefficient of the measuring device before the correction of heat loss, delay time, and reaction rate was verified. The heat loss coefficient of the measuring device was estimated by applying the water temperature change in the inside of the water to the equation (1). Since the concrete heat insulation temperature rise measuring device is used in the field, the test was carried out with the variables shown in Table 1 to simulate the temperature of the site. The external temperature was controlled using a thermostat. In the case of humidity, since the measuring device was made to maintain the sealed state, only the heat loss coefficient according to the temperature was estimated while excluding the influence of humidity. The heat loss coefficients according to the external temperature are as shown in Table 2. As one example, four measurement devices were manufactured and tested.

Experimental variable
(Experimental variables)
Internal temperature (℃) External temperature (℃) 55 20 10

10 ℃ 20 ℃ Device 1 0.787 0.796 Device 2 0.788 0.798 Device 3 0.786 0.795 Device 4 0.790 0.802

를 선택하는 것이 합리적이다.
As the results show, the internal and external temperatures do not significantly affect the heat dissipation factor inherent in the test equipment. The reason is that the thermal performance of the measuring device is very good, so the value of the heat loss coefficient calculated as the loss per hour does not change much. Therefore, in terms of safety, the heat loss coefficient is the largest value

It is reasonable to choose.

Thereafter, the heat loss correction (S352, S361) and the hydration reaction speed correction (S354, S362) due to the difference in ambient temperature are performed. However, the delay time correction S351 and the step S353 for obtaining the moving average of the temperature in the case of the ambient temperature change state are performed by first performing the heat loss correction S352 and S361 commonly performed in the ambient temperature and the constant temperature state, (S354, S362) due to the difference in the hydration reaction rate will be described hereinafter.

First, the heat loss correction (S352, S361) will be described.

In the case of a simple adiabatic temperature rise measurement device, the internal temperature of the concrete changes by the difference between the amount of heat generated due to the heat of hydration of concrete and the amount of heat lost to the outside. This can be expressed by the following equation (2).

Where ρ is the concrete unit weight, C is the specific heat of the concrete, t is time, V is the volume of the concrete, △ Q (t) is a heat quantity change the concrete, △ Q _hyd (t) is amount of heat generation due to heat of hydration, △ Q _out (t) is the amount of heat loss to the outside.

Equation (3) is a simplified equation for estimating the temperature distribution near the center of the cylinder in a one-dimensional condition, that is, an axisymmetric condition, when the upper and lower insulation performance is relatively better using the second-order polynomial .

Where h _a is the heat loss coefficient and is expressed as ? (T) in Equation ( 1 ) as described above. d is the diameter of the disposable mold.

Equation (3) is an expression derived when no heat is lost at the upper and lower surfaces of the portable thermal insulation temperature rise measuring device. However, even if the height / diameter ratio of the measuring device is maintained at 2 to 3 and the temperature is close to the one-dimensional heat loss condition as much as possible, a small amount of heat loss may occur on the upper and lower surfaces. This additional heat loss can be considered by multiplying Equation (3) by Equation (4).

는 추가 열손실 보정계수, h_{a ,t}는 윗면의 대류계수, h_{a ,b}는 아랫면의 대류계수, h_{a ,s}는 옆면의 대류계수, A_t는 윗면의 면적, A_b는 아랫면의 면적, A_s는 옆면의 면적이다.here

Is more heat loss correction coefficient, h _{a, t} is the convection coefficient of the upper surface, h _{a, b} is the convection coefficient of the lower surface, h _{a, s} is the convection coefficient of the side, A _t is the area of the top surface, A _b is the area of the lower surface , And A _s is the area of the side surface.

It is possible to estimate the corrected heat loss amount of the concrete heat insulation temperature rise amount measuring apparatus of the present invention by using equations (2) to (4) given by knowing the temperature distribution inside the concrete, the heat loss coefficient and the outside temperature.

This time, the hydration reaction rate correction (S354, S362) due to the difference in outside temperature will be described.

Actual adiabatic temperature rise test method is a method to measure the temperature rise amount generated by keeping the placed concrete in an adiabatic state, which is different from the simple adiabatic temperature rise measurement device. The reason is due to the rate of hydration reaction of concrete according to the outside temperature. Therefore, the lower the outside temperature in the early age, the slower the hydration reaction of concrete. Equation (5) is used to solve this problem. Equation (5) is an equation representing a reference temperature for a temperature at which the activation energy is varied. This gives the apparent activation energy of the concrete inside the measuring device.

Fig. 4 shows a method for determining the apparent activation energy of concrete in the curing temperature. This method was verified by replacing the apparent activation energy function with the reference temperature at the temperature of the transition state. Therefore, in calibrating the reaction rate, it is reasonable to use Equation (6) when the heat loss corrected temperature and the concrete curing temperature are temperature changes.

Where A is a proportional constant and R is a gas constant.

Equation (6) is the concrete maturity function of the ambient temperature at the transition temperature. After the apparent activation energy function is replaced with the reference temperature, it can be expressed as Equivalent Age of the reference temperature using the internal concrete temperature and the heat loss corrected temperature using Equation (7).

Where E ( T _i ) is the apparent activation energy function replaced with the reference temperature in i step, T is the curing temperature, and t is the aging. Using equations (5) to (7) for the internal concrete curing temperature history and the heat loss correction graph, the equivalent age expressed by the reference temperature of T _r can be obtained.

Where t is the age of the standard curing, t _ec is the equivalent age of curing temperature, t _ea is the equivalent age of the adiabatic temperature rise curve through heat loss correction, and t _er is the age corrected for the reaction rate.

Equation (8) is obtained by multiplying the standard curing by dividing the equivalent age of the concrete curing temperature by the equivalent age of the adiabatic temperature rise curve. As the method of correcting the reaction rate is repeated as described above, it converges close to the actual adiabatic temperature rise curve. Using the equations presented so far, it is possible to predict the increase in the adiabatic temperature regardless of the ambient conditions.

Hereinafter, the delay time correction S351 in the case of the ambient temperature change state and the process S353 of obtaining the moving average of the temperature will be described. First, the delay time correction S351 performed in the ambient temperature state will be described .

If the ambient conditions are isothermal, it is possible to compensate for the increase in the adiabatic temperature rise by the method described in Sections 3.1 and 3.2 above, but another correction is necessary if the outside temperature is temperature-dependent. The thickness of the simple adiabatic temperature rise measuring device is 70 mm between the portion where the concrete is poured and the surface that touches the outside air. For this reason, when the adiabatic temperature rise test is performed under the temperature change condition, a delay time due to the thickness occurs. Therefore, it is important to accurately calculate the delay time of the measuring device.

Where t _dh is the delay time (hour) and h _a is the heat loss coefficient.

Equation (9) is a delay time model equation found using finite element analysis. After finding the relationship between the heat loss coefficient and the delay time, the model equation is derived by regression analysis.

이므로 지연시간은 대략 5시간인 것을 알 수 있다. 외기가 변온일 경우, 장치 두께에 의한 지연시간이 발생하므로 외기온도를 열손실계수에 따라 초기부분에 지연시킨 후 열손실 보정을 실시하면 항온상태의 열손실 보정과 유사한 그래프를 얻을 수 있다. 도출한 지연시간을 적용하면 변온 상태의 열손실량 보정 과정에서 외기온도에 따른 장치 안의 콘크리트 내, 외부온도가 실시간으로 변한다는 조건을 만족한다.
In order to verify the model equation, each delay time is obtained using a thermos bottle having different heat loss coefficients and Equation 1, and is shown in FIG. As can be seen from FIGS. 5 and 9, it can be seen that the relationship between the heat loss coefficient and the delay time through the finite element analysis almost coincides with the experimental value. The delay time becomes longer as the heat loss coefficient goes to zero. Actually manufactured measuring devices have a heat loss coefficient of

The delay time is approximately 5 hours. In the case of ambient temperature change, a delay time due to the thickness of the device occurs. Therefore, when the outside temperature is delayed to the initial portion according to the heat loss coefficient and the heat loss correction is performed, a graph similar to the heat loss correction at the constant temperature can be obtained. The applied delay time satisfies the condition that the temperature inside and outside of the concrete changes in real time according to the outside temperature in the process of correcting the heat loss of the transformed state.

In this case, the process of obtaining the moving average of the temperature (S353) when the ambient temperature is in the ambient temperature condition will be described.

In the case where the ambient condition is a temperature change, tremor occurs as shown in FIG. 6 when the heat loss and the correction of the delay time are used. The reason for this is that when the integration is applied in the process of applying the heat loss correction, the change in the outside air temperature is larger than the temperature of the internal concrete, so that the difference in the area over time occurs even considering the average temperature change and heat loss inside the concrete. In this case, when recalibrating the reaction rate by using the apparent activation energy function, there is a limit in which the vibration can be seen because the equivalent age is used. A moving average can be used as a solution to this problem. In Equation 3, heat loss is corrected by integrating the difference between the outside temperature and the outside temperature of the concrete. Therefore, since the result obtained by integrating using the moving average is the same according to the age, the tremor can be solved as shown in Fig. In this embodiment, the moving average is used for the outside of the concrete, the inside temperature, and the outside temperature at intervals of one step every 24 hours. Considering delay and moving averages where climate or exposure conditions change significantly, the heat loss correction graph can be represented smoothly.

FIG. 7 is a diagram illustrating a configuration of a predicted value of the adiabatic temperature rise amount calculating unit 150 for measuring the amount of increase in the adiabatic temperature of concrete in the concrete adiabatic temperature rise amount measuring apparatus 100 according to the present invention. Since the process for calculating the predicted value of the adiabatic temperature rise amount according to the present invention has been described in detail with reference to Figs. 1 to 6, the predicted value of the adiabatic temperature rise amount calculation unit 150 ) Will be briefly described mainly with respect to the function of each module.

The control unit 151 controls the respective modules of the heat insulation temperature rise amount prediction value calculation unit 150 to perform a series of processes related to the calculation of the predicted value of the heat insulation temperature rise amount.

The heat loss coefficient calculation module 152 calculates the heat loss coefficient of the concrete heat insulation temperature rise amount measurement device 100.

The delay time correction module 153 calculates the delay time according to the thickness of the wall where the concrete insulation temperature rise amount measuring apparatus 100 is in contact with the outside air in the ambient temperature change state, .

The heat loss correction module 154 is a module for calculating the amount of heat loss by correcting the amount of additional heat loss to the upper and lower surfaces.

The temperature moving average calculation module 155 is a module for calculating the middle value, that is, the average value, of the fluctuation of the temperature rising and falling as the temperature is fluctuated when the temperature of the outside air is changed.

The reaction rate correction module 156 is a module for correcting the hydration reaction rate due to the difference in ambient temperature.

The predicted value of the adiabatic temperature rise amount calculation module 157 calculates the predicted value of the adiabatic temperature rise amount to which the heat loss correction and the reaction rate correction are applied in the case of the outside air constant temperature and calculates the heat loss correction and the temperature moving average The predicted value of the adiabatic temperature rise is calculated.

8 is a photograph of a concrete heat insulation temperature rise tester, and FIG. 9 is a view showing an adiabatic temperature rise curve.

The concrete adiabatic temperature rise tester is a device for performing the actual adiabatic temperature rise test for comparison with the concrete adiabatic temperature rise measurement device. The principle of the tester is to maintain the adiabatic condition of the test body by air circulation method, measure the temperature rise amount by the time elapsed by the hydration reaction of the concrete, and measure the maximum adiabatic temperature and the reaction rate. The specifications of the tester are shown in Table 3.

Temperature range + 10 ° C to + 80 ° C Psalm volume Temperature accuracy inside and outside the specimen Temperature rising and falling accuracy of specimen-free state

Water, and cement ratio for two comparisons. The formulation is shown in Table 4.

w / b (%)
s / a (%) Unit weight (kg / m ³ ) W C S G SP Test 1 30 40.7 170 566 639 933 3.9 Test 2 50 44.7 182 364 761 943 2.4

Fig. 9 shows the results of the heat insulation test for high-strength concrete and general concrete. As a result of the actual heat insulation test, it can be seen that the heating value and the reaction speed of the high strength concrete are higher, and the actual heat insulation temperature rise test is reasonable.

FIG. 10 is a view showing a verification test apparatus of an apparatus for measuring an elevated amount of concrete adiabatic temperature according to the present invention, and FIG. 11 is a view showing a temperature history due to heat loss correction under an ambient temperature constant temperature condition.

In the various ambient temperature distributions, only the heat loss was corrected by using the heat loss coefficient of the measuring device obtained above and compared with the actual heat insulation temperature rise test. The test was carried out at the laboratory using the same compounding and materials as the test using the adiabatic temperature rise tester. The concrete unit weight was 2300 kg / m ³ , and the specific heat of concrete was 0.28 kcal / kg · ° C, which is an intermediate value between 0.26 and 0.30 kcal / kg · ° C.

The initial temperature of the concrete for various ambient temperature distribution conditions is shown in Table 5. In the measurement of the temperature rise of the test apparatus, the center point and the surface portion of the previously assumed sample were measured, and a K type thermocouple was used for the measurement.

20 ℃ 10 ℃ Indoor (temperature) Outdoor (temperature change) Test 1 22.7 ° C 22.4 DEG C 23.2 DEG C 22 ℃ Test 2 20.4 DEG C 20.4 DEG C 19.1 DEG C 18.1 DEG C

If the ambient temperature is constant, the process of predicting the adiabatic temperature rise at constant temperature can be solved by heat loss correction and reaction rate correction. Fig. 11 shows the correction of the heat loss at the constant temperature and the actual increase in the adiabatic temperature, but it can be seen that the amount of increase in the adiabatic temperature of the concrete in the test device corrected for the heat loss is different. The reason is that the outside temperature does not follow the internal temperature of the concrete, which is different from the reaction rate of the actual adiabatic temperature rise. Therefore, it is necessary to reevaluate the reaction rate in the heat loss correction.

11 (b) and (d) show that the difference in the actual heat insulation temperature rise and the reaction speed are different from each other when the heat loss correction is applied, compared with the constant temperature of 20 ° C. Because the device also maintains the temperature according to the outside temperature, the rate of hydration reaction differs more. Therefore, in correcting the reaction rate, the variable value can be expressed as a function of temperature as shown in Equations (10) and (11).

Equations (10) and (11) are values obtained by regression analysis of the compression strength values for each combination. As can be seen from Equations (10) and (11), the lower the water cement ratio, the higher the reaction rate depends on the temperature, and the apparent activation energy value decreases rapidly with temperature. This can be seen from the actual increase in the adiabatic temperature. The higher the unit cement amount, the higher the heating value of hydration and the faster the reaction rate.

FIG. 12 is a diagram for comparing predicted values of an adiabatic temperature rise and a concrete adiabatic temperature rise amount measurement device under an ambient-temperature constant temperature condition.

If the outside temperature is constant, the reaction rate can be recalculated to compensate for the existing heat loss to be similar to the actual adiabatic temperature rise. At this time, repeating Equation (9) converges more closely to the actual adiabatic temperature rise amount. Fig. 12 (b) differs from the reaction rate of the actual adiabatic temperature rise as shown in Figs. 11 (b) and (d) because the outside temperature is low. therefore. You can see that age is getting faster.

13 is a view showing the temperature history by heat loss correction under the ambient temperature change condition.

When the outside air temperature is a temperature change, prediction of the adiabatic temperature rise amount can be obtained through heat loss, delay time, and reaction rate correction. Equation (3) is heat loss correction when the outside temperature and the concrete temperature change together according to the age. However, there is a delay time depending on the thickness of the device.

Referring to FIG. 13, there is a difference in reaction rate depending on the outside temperature. Further, in the case of outdoor use, since the change of the outside air temperature is severe, the result of the heat loss correction is also remarkable. The reason is as described above with reference to FIG. 5 and FIG.

14 is a diagram showing a heat loss correction considering the delay time and the moving average in the ambient temperature change condition.

Comparing FIG. 14 with FIG. 12, it can be seen that the fluctuation phenomenon of heat loss correction is reduced. In this case, since the outside temperature is almost constant, it is not necessary to consider the delay time because there is no big problem in determining the reaction rate and the maximum adiabatic temperature rise without considering the moving average.

FIG. 15 is a graph showing the results of correcting heat loss, delay time, and reaction speed under ambient temperature condition.

The delay time of Equation (9) and the reaction rate correction of Equations (6) to (8) are similar to the actual adiabatic temperature rise amount. Since the outside temperature is low, it can be seen that when it is expressed as equivalent age, it is pulled a lot.

Fig. 16 is a view showing an error range of an actual adiabatic temperature rise amount and a resultant value obtained by the concrete adiabatic temperature rise amount measurement according to the present invention.

5%, and compared the predicted adiabatic temperature rise. However, in the initial part, we can see an error of more than 5%, which is an error caused by the unequal initial temperature. Therefore, if the initial temperature is adjusted exactly, the error range can be reduced at the initial age.

As described above, when the outside air temperature is changed to the outside temperature, it is understood that the room temperature is low and the shaking is small when the room temperature is inside. That is, since the outside air temperature is almost constant, the actual adiabatic temperature rise amount can be obtained without considering the moving average. However, if the temperature is outside the temperature range and the outside temperature is not constant, the predicted value may not be accurate due to the seasonal variation. Therefore, it is important to conduct the experiment with an initial temperature of ± 15 ° C when the initial temperature is 20 ° C. This is because the more the change is, the more the calculation error may occur in performing the delay time and the shake correction.

If the actual adiabatic temperature rise amount is 3 days, the maximum adiabatic temperature rise amount is reached. Since the predicted adiabatic temperature rise is shown as the age after 3 days, it can be used without any problem in the analysis of the thermal stress related to cracks. If the range is beyond the range, the prediction may be inaccurate because the equivalent age is taken into account within 3 days. Therefore, when using the simple adiabatic temperature rise measurement device, it is important to perform the temperature measurement until 10 days and use the correction method described above.

In the present invention, the apparatus for measuring the amount of rise in the adiabatic temperature of concrete is completed and its validity is verified. Estimation of the heat loss coefficient of the measuring device by using the proposed equation and the amount of increase of the heat loss of the concrete by predicting the heat loss, reaction rate and delay time were predicted. And the objectivity and feasibility of the simple adiabatic temperature rise measurement device were verified through verification with the actual adiabatic temperature rise amount. The results of the present invention are summarized as follows.

1. Prediction of adiabatic temperature rise by conventional heat loss correction is different in reaction rate. In this study, the reaction rate is corrected by the ambient temperature according to the equivalent age using the apparent activation energy function.

2. The delay time considering the thickness of the device was taken into consideration in the case where the outside air temperature was in the temperature change state. Therefore, it can be applied in actual field.

3. When the outside temperature is constant, predictions similar to the actual adiabatic temperature rise can be obtained by heat loss correction and reaction rate correction.

4. If the outside temperature is low, replacing it with equivalent age by using the result of heat loss correction will pull it up to the age when the temperature rise of the actual insulation temperature rise occurs. Therefore, And the ambient temperature should be measured.

5. It can be seen that the predicted concrete insulation temperature rise by the measuring device is almost similar to the actual insulation temperature rise and within the error range of 5%.

100: Measuring device for temperature rise of concrete
110: Concrete sample part
120: internal temperature sensor unit
130: External temperature sensor unit
150: Adiabatic temperature rise amount prediction value calculating unit

Claims (11)

A method for measuring a rise in the adiabatic temperature of a concrete,
(a) measuring the temperature of the concrete sample in the concrete heat insulation temperature rise measuring device and the temperature outside the concrete insulation heat rise measuring device;
(b) calculating a heat loss coefficient of the concrete adiabatic temperature rise measurement device;
(c) performing a heat loss correction of the concrete adiabatic temperature rise measurement device;
(d) correcting the hydration reaction rate; And
(e) calculating a predicted value of the adiabatic temperature rise amount of the concrete sample
Lt; / RTI >
In the step (d)
The age at which the reaction rate was corrected,

Lt; / RTI >
Where t is the curing time, t _ec is equivalent age, t _ea of the curing temperature of the curing is the standard adjustment for age equivalent age, _er t is the reaction rate of the adiabatic temperature rise curve through heat loss compensation,
Applying the t _er to the time axis value of the adiabatic temperature rise curve
Wherein said method comprises the steps of: The method according to claim 1,
The heat loss coefficient,

Lt; / RTI >
Where α (t) is the heat loss coefficient of the device for measuring the temperature rise of concrete,

The average temperature change in the concrete,

Is the surface temperature of the concrete at time t,

Is the ambient temperature of the concrete at time t
Wherein said method comprises the steps of: delete The method according to claim 1,
When the external temperature is in a state of temperature change,
Before the step (c)
Calculating a delay time due to the wall thickness of the concrete heat insulation temperature rise amount measuring device
Further comprising:
Applying the calculated delay time to the heat loss correction in the step (c)
Wherein said method comprises the steps of: The method of claim 4,
The delay time,

Lt; / RTI >
Where t _dh is the delay time (hour) and h _a is the heat loss coefficient
Wherein said method comprises the steps of: The method according to claim 1,
When the external temperature is in a state of temperature change,
Prior to step (d)
(Hereinafter referred to as "moving average of temperature") of the rising and falling points of the concrete with respect to the fluctuation of the concrete temperature repeatedly rising and falling
Further comprising the step of measuring the temperature rise of the concrete. An apparatus for measuring an increase in the adiabatic temperature of concrete,
A concrete specimen portion into which a concrete specimen to be measured is injected;
An internal temperature sensor for measuring the temperature of the concrete sample in the apparatus for measuring the increase of the adiabatic temperature of the concrete;
An external temperature sensor unit for measuring the temperature of the outside of the apparatus for measuring the increase of the adiabatic temperature of the concrete; And
A predicted value of the adiabatic temperature rise amount of the concrete sample;
Lt; / RTI >
Wherein the heat insulation temperature rise amount prediction value calculation unit calculates,
A heat loss coefficient calculating module for calculating a heat loss coefficient of the concrete heat insulation temperature rise measuring device;
A heat loss correction module for correcting the additional heat loss amount to the upper and lower surfaces to obtain a heat loss amount;
A reaction rate correction module for correcting a hydration reaction rate due to a difference in ambient temperature;
An adiabatic temperature rise amount predicted value calculating module for calculating a predicted value of the adiabatic temperature rise amount to which the heat loss correction and the reaction rate correction are applied; And
And a controller for controlling the modules of the predicted value of the predicted value of the adiabatic temperature rise to perform a series of processes related to the predicted value of the predicted value of the adiabatic temperature rise,
Lt; / RTI >
The reaction rate correction module corrects the reaction rate,

Lt; / RTI >
Where t is the curing time, t _ec is equivalent age, t _ea of the curing temperature of the curing is the standard adjustment for age equivalent age, _er t is the reaction rate of the adiabatic temperature rise curve through heat loss compensation,
Applying the t _er to the time axis value of the adiabatic temperature rise curve
And the temperature of the concrete. The method of claim 7,
Wherein the heat insulation temperature rise amount prediction value calculation unit calculates,
A delay time correction module for calculating the delay time according to the thickness of the wall where the concrete heat insulation temperature rise measuring device 100 is in contact with the outside air,
Further comprising a temperature sensor for detecting the temperature rise of the concrete. The method of claim 7,
Wherein the heat insulation temperature rise amount prediction value calculation unit calculates,
A temperature moving average calculation for calculating a mean value of rising and falling points (hereinafter, referred to as 'temperature moving average') with respect to a shaking phenomenon of concrete which repeats rising and falling repeatedly in the case of ambient temperature, module
Further comprising a temperature sensor for detecting the temperature rise of the concrete. The method of claim 7,
The predicted value of the adiabatic temperature rise amount calculating module calculates,
The heat loss correction using the delay time correction and the reaction velocity correction using the moving average of the temperature are further applied to calculate the predicted value of the adiabatic temperature rise amount
And the temperature of the concrete. The method of claim 7,
A display unit that displays data of the predicted value of the adiabatic temperature rise amount and a predicted value of the calculated adiabatic temperature rise amount and provides an interface that can be controlled by the user in the process;
Further comprising a temperature sensor for detecting the temperature rise of the concrete.

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