JP7300982B2 - Concrete Exothermic Characteristic Test Apparatus and Exothermic Characteristic Test Method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a concrete heat generation characteristic testing apparatus and a heat generation characteristic testing method.

In the construction of mass concrete structures, thermal cracking caused by heat of hydration of cement is preliminarily checked by thermal stress analysis. Thermal stress analysis uses concrete heat generation rate as input data. According to the Japan Society of Civil Engineers Concrete Standard Specifications (established in 2012), "In principle, the heat generation rate of concrete used for temperature analysis of concrete should be modeled in consideration of the age of the concrete and the temperature of the concrete, which varies from place to place. It is said that Therefore, the exothermic rate is obtained as a function of temperature, and this function is also called the temperature-dependent hydration exothermic rate equation. An adiabatic temperature rise test of concrete is performed to calculate the temperature-dependent hydration exotherm rate equation. This test is generally carried out using a test apparatus equipped with heating means and cooling means. A container filled with concrete is placed in the test equipment, and the temperature change of the concrete is measured while controlling the temperature of the concrete. Adiabatic requirements are met by controlling the temperature in the test apparatus to be equal to the temperature of the concrete. However, the test equipment is relatively large, and is assumed to be installed in a research facility or the like.

Patent Literature 1 discloses a method of estimating the amount of adiabatic temperature rise of concrete using a device with a relatively simple configuration. A test piece is placed in an insulated container made of polystyrene foam, and the temperature change of the test piece due to the heat generated by the concrete is measured. Next, a plurality of adiabatic temperature rise amounts of concrete per unit time are set, and the temperature change of the specimen is analyzed using a temperature analysis model. The analysis takes into consideration the amount of heat released from the heat-insulated container. The adiabatic temperature rise that gives the analysis result closest to the measured value is estimated to be the adiabatic temperature rise of the specimen. The calorific value of the specimen is obtained by multiplying the adiabatic temperature rise by the heat capacity of the specimen.

JP 2008-292252 A

Since the method described in Patent Literature 1 uses an insulated container with a simple configuration, the cost of the test can be suppressed. On the other hand, since the heat generation rate of concrete increases as the temperature of the concrete increases, the integrated heat generation amount decreases when the temperature of the concrete decreases due to heat radiation. Since the method described in Patent Document 1 allows heat dissipation, there is a possibility that the calorific value of concrete may be underestimated.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a concrete heat generation characteristic test apparatus and a heat generation characteristic test method capable of suppressing heat radiation with a simple device and safely evaluating the heat generation characteristic of concrete.

The apparatus for testing heat generation characteristics of concrete according to the present invention comprises a heat insulating container having an internal space in which a filled container filled with concrete is placed, and a circumference of the internal space between the side wall of the heat insulating container and the setting area of the filled container. a heating element arranged in a shape and a plane, a control means for controlling the heating element, a first thermometer arranged inside the filling container, and a second thermometer arranged between the filling container and the heating element and a thermometer of The control means obtains the temperature difference T2-T1 between the first temperature T1 measured by the first thermometer and the second temperature T2 measured by the second thermometer, and generates heat so that the temperature difference becomes positive. control the body.

The method for testing heat generation characteristics of concrete according to the present invention includes placing a filled container filled with concrete in a test container equipped with a heat generating element, controlling the heat generating element by a control means when the concrete heats up, have. The filling container is installed in the inner space of the heat insulating container of the test container, and the heating element is circumferentially and planarly arranged between the side wall of the heat insulating container and the setting area of the filling container. A temperature is measured at a first location inside the filled vessel and at a second location between the filled vessel and the heating element. The controller obtains the temperature difference T2-T1 between the first temperature T1 measured at the first position and the second temperature T2 measured at the second position, and rotates the heating element so that the temperature difference is positive. Control.

The heating element is controlled such that the temperature T1 measured inside the filling container and the temperature T2 measured outside the filling container satisfy the relationship of T2>T1. That is, the heating element is controlled so as not to allow heat dissipation from the concrete from the filling container. Therefore, it is possible to evaluate the heat generation characteristics of concrete on the safe side. Therefore, according to the present invention, it is possible to provide an apparatus and method for testing heat-generating characteristics of concrete, which can suppress heat radiation with a simple device and can evaluate the heat-generating characteristics of concrete on the safe side.

1 is a schematic configuration diagram of an apparatus for testing heat generation characteristics of concrete according to an embodiment of the present invention; FIG. Fig. 3 is an exploded perspective view of a heat insulating container; It is an exploded perspective view of a seat heater and its support cylinder. 1 is an exploded perspective view of a concrete filling container and its installation jig; FIG. 3 is a schematic block diagram of a measurement control system of the heat generation characteristic testing device; FIG.

An embodiment of the present invention will be described below with reference to the drawings. Although the present invention can be applied to any kind of concrete, it can be suitably applied to concrete used in mass concrete structures, particularly mass concrete structures for which the Standard Specifications for Concrete require temperature stress analysis for temperature cracks.

FIG. 1 is a schematic configuration diagram of a concrete heat generation characteristic testing apparatus 1. As shown in FIG. The exothermic characteristic testing device 1 has a test container 2 . The test container 2 has a heat insulating container 3 having an internal space 31 and a seat heater 4 installed in the internal space 31 . A filling container 5 filled with concrete is installed in the internal space 31 .

FIG. 2 shows an exploded perspective view of the heat insulating container 3. As shown in FIG. The heat insulating container 3 has an outer container 6 and an inner container 7 housed in the outer container 6 . The outer container 6 and the inner container 7 are made of a material having a lower heat transfer coefficient than the filled container 5 . The outer container 6 is a hollow container consisting of a container body 61 and an upper lid 62 . The container body 61 is a cylindrical member having a cylindrical inner space and a bottom plate, and a circular opening 63 is provided at the top. The upper lid 62 is a disc-shaped member fitted in the opening 63 .

The inner container 7 is a hollow container comprising a body portion 71 , a top lid 72 and a bottom plate 73 . The body portion 71, the upper lid 72, and the bottom plate 73 have substantially the same outer diameter as the inner diameter of the outer container 6 of the heat insulating container 3, and are inserted into the outer container 6 with almost no gap. The body portion 71, the upper lid 72 and the bottom plate 73 form a substantially closed internal space 31. As shown in FIG. The internal space 31 forms a space in which the filling container 5 is installed. By providing the outer container 6 and the inner container 7, the heat insulating performance of the heat insulating container 3 can be enhanced. Since the inner wall of the inner container 7 is in contact with the seat heater 4, it has high heat resistance. Although the outer container 6 does not need to have the same level of heat resistance as the inner container 7 , it is preferable that the outer container 6 is light because it has a larger volume than the inner container 7 . By reducing the weight of the outer container 6, the weight of the test container 2 can be suppressed and the mobility can be improved. That is, it is desirable that the outer container 6 has a lower specific gravity than the inner container 7 and that the inner container 7 has a higher heat resistance than the outer container 6 . In this embodiment, the outer container 6 is made of expanded polystyrene and the inner container 7 is made of alkaline earth silicate (AES) wool. The heat-resistant temperature of polystyrene foam is about 80.degree. C., and the surface temperature of the seat heater 4 may rise up to about 150.degree. The heat resistance temperature of AES wool is about 1300°C. By disposing the inner container 7 between the outer container 6 and the seat heater 4, the outer container 6 can be protected. The inner container 7 can also be made of glass wool, rock wool, urethane, or the like.

FIG. 3 shows an exploded perspective view of the seat heater 4 and its support cylinder 8. As shown in FIG. A lead wire 41 and a thermometer 42 are embedded in the seat heater 4 . A T-type thermocouple is used as the thermometer 42 . The support barrel 8 is a cylindrical member made of stainless steel and has a cylindrical barrel portion 81 and a circular bottom plate 82 connected to the barrel portion 81 . The seat heater 4 is wound around the outer peripheral surface of the body portion 81 . The bottom plate 82 is used as a base for setting the filling container 5 . The seat heater 4 is a generally rectangular planar heating element when unfolded, and has a loop-shaped fastener 43 on one short side via a spring 44 and a hook that engages with the fastener 43 on the other short side. 45 are provided. The seat heater 4 can be fixed to the support body 8 by winding the spring 44 around the body part 81 while pulling it and engaging the fastener 43 with the hook 45 . The seat heater 4 fixed to the support cylinder 8 is installed in the internal space 31 of the inner container 7 . The seat heater 4 is circumferentially arranged between the inner surface of the inner container 7 and the installation area of the filling container 5 in the inner space 31 formed by the heat insulating container 3 . The seat heater 4 is in close contact with the inner surface of the inner container 7, but a small gap may be provided.

The seat heater 4 is an example of a heating element that is circumferentially and planarly arranged between the side wall of the heat insulating container 3 and the installation area of the filling container 5, and any type of heating element can be used as long as it can heat concrete. be able to. For example, it is possible to arrange a plurality of infrared lamps or halogen lamps circumferentially and planarly between the side wall of the heat insulating container 3 and the installation area of the filling container 5 . However, the seat heater 4 is the most excellent heating element because of ease of installation and control.

An annular space is formed between the seat heater 4 and the filling container 5 . This embodiment has several advantages over the method of directly wrapping the seat heater 4 around the filling container 5 . First, since the seat heater 4 incorporates a fine heating element, the surface temperature is slightly uneven. By providing a space between the seat heater 4 and the filling container 5, the filling container 5 is heated more uniformly. Particularly in this embodiment, the support cylinder 8 inside the seat heater 4 is heated by the seat heater 4, and the radiant heat of the support cylinder 8 is transmitted to the filling container 5 through the annular space, so that the filling container 5 is uniformly heated. be done. Further, when the seat heater 4 is directly wrapped around the filling container 5, the work of wrapping the seat heater 4 around the filling container 5 is required for each test. In this embodiment, since the seat heater 4 is part of the test container 2, it is only necessary to set the filling container 5 in the test container 2 at the time of testing, which simplifies the test process.

FIG. 4 shows an exploded perspective view of the filling container 5 and its mounting jig 9. As shown in FIG. FIG. 4(a) is a perspective view of the filling container 5 and the mounting jig 9, and FIG. 4(b) is a cross-sectional view taken along line AA in FIG. 4(a). The filling container 5 is a closed cylindrical container made of tinplate. The filling container 5 functions not only as a container for containing concrete specimens, but also as a formwork for concrete. For the filling container 5, for example, a commercially available product such as a concrete specimen molding form "Summit Mold" manufactured by Marui Co., Ltd. can be used. The dimensions of the filling container 5 are, for example, approximately 150 mm in diameter and approximately 300 mm in height. The shape of the filling container 5 is not limited to a cylindrical shape, and the cross section perpendicular to the vertical center line may be a polygonal shape such as a square or an octagon. The installation jig 9 has a bottom plate 91 for installing the filling container 5 , a top plate 92 for holding the top plate of the filling container 5 , and a plurality of rods 93 connecting the bottom plate 91 and the top plate 92 . The top plate 92 is provided with a hole 95 through which the rod 93 passes, and the rod 93 is fixed to the top plate 92 with an eyenut 94 . A hole 96 is provided in the center of the top plate 92 for drawing out the lead wires of the first and third thermometers 101 and 103 (described later). The edge of the top plate 92 is provided with notches 97 for drawing out the lead wires of the second and fourth thermometers 102, 104 (described later) and the first to third heat flow sensors 111-113. By holding the filling container 5 with the mounting jig 9 and suspending it with the eyenut 94 , the filling container 5 can be quickly and safely mounted on the test container 2 . The space between the filling container 5 and the test container 2, that is, the space between the outer surface of the filling container 5 and the inner surface of the support cylinder 8, is determined in consideration of the installation space for the mounting jig 9, and is about 30 mm in one example. The filling container 5 is preferably placed in the center of the test container 2 so as to be coaxial with the support cylinder 8 .

First to fourth thermometers 101 to 104 consisting of T-type thermocouples are attached to the filling container 5 . The first thermometer 101 and the third thermometer 103 are installed on the sheath 51 coaxial with the central axis of the filling container 5, and are located at the center of the filling container 5 in the radial direction and the height direction (hereinafter referred to as the first position P1). ) is measured (hereinafter referred to as the first temperature T1). The sheath 51 is a tubular member extending from the top plate to the bottom plate of the filling container 5, and is installed in the filling container 5 before being filled with concrete. It is preferable to install the first thermometer 101 and the third thermometer 103 at the same position as much as possible. The second thermometer 102 and the fourth thermometer 104 are affixed to the outer surface of the filling container 5 (hereinafter referred to as second position P2) and measure the temperature outside the filling container 5 (hereinafter referred to as second temperature T2). ) is measured. It is preferable to install the second thermometer 102 and the fourth thermometer 104 at the same position as much as possible. In this embodiment, the first to fourth thermometers 101 to 104 are installed near the center of the filling container 5 in the height direction.

Furthermore, first to third heat flow sensors 111 to 113 are attached to the filling container 5 . The first to third heat flow sensors 111 to 113 measure the calorie density of heat entering and leaving the filled container 5 in a direction orthogonal to the outer surface thereof. As will be described later, the first to third heat flow sensors 111 to 113 measure the heat flow density of heat from the seat heater 4 into the filled container 5, ie, from the seat heater 4 into the concrete. The heat flow sensor is attached to the outer surface of the filling container 5 with thermally conductive double-sided tape. Although the heat flow sensor may be provided at only one location, it is preferable to provide it at a plurality of locations. In this embodiment, three first to third heat flow sensors 111 to 113 are provided at intervals of 120° in the circumferential direction at a height where the central position of the heat sensitive portion coincides with the central position in the height direction of the filling container 5. ing. By providing three heat flow sensors 111 to 113, when one heat flow sensor indicates an abnormal value, the heat flow sensor is considered to be abnormal, and only the measured values of the remaining two heat flow sensors excluding the heat flow sensor are measured. can be adopted. The installation position and installation number of the heat flow sensors are not limited to this, and can be installed on the bottom surface of the filling container 5, for example.

FIG. 5 is a schematic block diagram of the measurement control system of the heat generation characteristic testing apparatus 1. As shown in FIG. For convenience of illustration, the first thermometer 101 and the third thermometer 103 are provided at different positions, but as described above, they are installed at substantially the same position. The same is true for the second thermometer 102 and the fourth thermometer 104 . The first thermometer 101 and the second thermometer 102 are connected to the temperature difference meter 11 , and the temperature difference meter 11 is connected to the lead wire 41 of the seat heater 4 . The temperature difference meter 11 functions as control means for the seat heater 4 . The temperature difference meter 11 obtains the temperature difference T2-T1 between the temperature T1 measured by the first thermometer 101 and the temperature T2 measured by the second thermometer 102, and adjusts the temperature difference T2-T1 to be positive. The seat heater 4 is controlled. A third thermometer 103 and a fourth thermometer 104 are connected to the data logger 12 . Since the outputs of the first thermometer 101 and the second thermometer 102 are used as input signals to the temperature difference meter 11, they cannot be used for the purpose of recording and managing the concrete temperature. Therefore, the outputs of the third thermometer 103 and the fourth thermometer 104 provided near the first thermometer 101 and the second thermometer 102 are transmitted to the data logger 12, and the data logger 12 Record concrete temperature time history data. The first to third heat flow sensors 111 to 113 are also connected to the data logger 12, and the data logger 12 records the time history data of the heat quantity density measured by each of the heat flow sensors 111 to 113. Time history data of the temperature of the seat heater 4 measured by the thermometer 42 is also recorded in the data logger 12 .

Next, the procedure of the heat generation characteristic test method of this embodiment will be described.

(Step 1)
First, the above-described test container 2 and filling container 5 are prepared. The filling container 5 is filled with concrete and the filling container 5 is sealed. A first thermometer 101 and a third thermometer 103 are arranged inside the sheath 51 through a hole 96 in the center of the top plate 92 of the filling container 5 , and a second thermometer 102 and a fourth thermometer are arranged on the outer surface of the filling container 5 . A thermometer 104 is placed. First to third heat flow sensors 111 to 113 are further arranged on the outer surface of the filling container 5 , and the filling container 5 is installed in the test container 2 using the mounting jig 9 . Cables of the first and third thermometers 101 and 103 are pulled out from the center hole 96 of the top plate 92 . The cables of the second and fourth thermometers 102, 104 and the first to third heat flow sensors 111 to 113 are pulled out from the notch 97 of the top plate 92 in advance. Next, the upper lid 72 of the inner container 7 and the upper lid 62 of the outer container 6 are attached. The cables of the first to fourth thermometers 101 to 104 and the first to third heat flow sensors 111 to 113 are connected through holes (not shown) provided in the upper lid 72 of the inner container 7 and the upper lid 62 of the outer container 6, respectively. ) to the outside of the test container 2 . These cables are then connected to a thermometer 11 or data logger 12 as shown in FIG. The seat heater 4 is connected to the temperature difference gauge 11 and set to a state in which on/off control by the temperature difference gauge 11 is possible. The hydration reaction of concrete usually starts several hours after mixing. Therefore, the above work can be completed before the concrete starts to heat up. The space between the support cylinder 8 and the filling container 5 is filled with air, but may be filled with a liquid such as water. There is a possibility that the temperature change with respect to turning on/off of the seat heater 4 becomes slow, and the control becomes easier.

(Step 2)
Measurement of the first and second temperatures T1 and T2 and heat flow density and control of the seat heater 4 are started. A first temperature T1 at a first position P1 is continuously measured by a first thermometer 101 and a second temperature T2 at a second position P2 is continuously measured by a second thermometer 102, and the temperature difference meter 11 is entered. Similarly, a first temperature T1 at a first location P1 is continuously measured by a third thermometer 103 and a second temperature T2 at a second location P2 by a fourth thermometer 104 and data loggers 12. Heat flux densities are continuously measured by the first to third heat flux sensors 111 - 113 and stored in the data logger 12 . Outside air temperature may be measured if necessary. Concrete generates heat over time, and the first temperature T1 and the second temperature T2 gradually rise. Since the hydration reaction occurs almost uniformly within the concrete sample, if the filling container 5 is placed in a completely adiabatic state, the temperature of the concrete will be constant throughout the sample. However, due to heat transfer across the boundary surfaces of the filled container 5, a temperature difference occurs between the first temperature T1 and the second temperature T2. When heat insulation is performed only by the heat insulating container 3 under a general room temperature environment, heat is dissipated from the filled container 5 and heat is released. The concrete temperature is highest at the center (first position P1) of the filling container 5 and lowest at the wall surface of the filling container 5, where T2<T1. On the other hand, in this embodiment, the seat heater 4 is controlled so that T2>T1, that is, the temperature difference T2-T1 becomes positive when the concrete heats up. Basically no heat is radiated from the concrete, only the concrete is heated. As a result, the first to third heat flow sensors 111 to 113 measure the heat flow density of heat entering the filling container 5 (heat supplied to concrete).

A temperature difference meter 11 performs ON/OFF control of the seat heater 4 with a predetermined temperature difference as a target value. Although the control method is not particularly limited, PID control is used in this embodiment. First, the seat heater 4 is energized, and when the temperature difference T2-T1 reaches a positive target value, the temperature difference meter 11 deenergizes the seat heater 4. FIG. When the temperature difference T2-T1 falls below the target value, the temperature difference meter 11 turns the seat heater 4 on. As a result, heat is supplied from the seat heater 4 to the filling container 5, and the second temperature T2 rises. On the other hand, since the rate of increase of the first temperature T1 is slower than the rate of increase of the second temperature T2, the temperature difference T2-T1 increases. When the temperature difference T2-T1 reaches a positive target value, the temperature difference meter 11 brings the seat heater 4 into a non-energized state. As a result, the rate of increase of the second temperature T2 is reduced, and in some cases the second temperature T2 begins to decrease. The temperature difference T2-T1 gradually decreases, but when it falls below the target value, the temperature difference meter 11 makes the seat heater 4 energized again. By repeating the above operation, the seat heater 4 maintains the temperature difference T2-T1 near the target value. The target value of the temperature difference T2>T1 is about 0.5 to 1.5 degrees, and is preferably set to increase as the concrete temperature increases. If the temperature difference T2-T1 is small, the possibility of heat dissipation increases. If the temperature difference T2-T1 is large, the heat flow density becomes large, and there is a possibility that the calculation error of the calorific value of concrete becomes large.

(Step 3)
The above steps are performed for a plurality of concretes with different pouring temperatures. For example, steps 1 and 2 are repeated for three cases of implantation temperatures of 10°C, 20°C and 30°C. The plurality of concretes are preferably of the same mix, more preferably of the same batch.

(Step 4)
Next, a temperature-dependent hydration exotherm rate equation is calculated based on the obtained data. The temperature-dependent hydration exotherm rate equation can be expressed as follows.

here,
H : Hydration heat generation rate of cement per unit weight Q: Cumulative calorific value of cement per unit weight
H _∞ (Q): critical hydration exotherm rate (Q)
-E(Q)/R: Cement temperature activity T: Concrete temperature log H _∞ (Q) and -E(Q)/R are obtained from the cumulative calorific value Q calculated for multiple concretes with different pouring temperatures. I know I will. The first temperature T1 recorded by the data logger 12 is used as the concrete temperature. Therefore, the temperature-dependent hydration heat rate equation can be calculated by obtaining the cumulative heat value Q for each concrete having different pouring temperatures.

The integrated calorific value is obtained from the following formula.
Q=cρΔT/C ^* -Qd/C ^* /V (Formula 2)
here,
c: Specific heat of concrete ρ: Density of concrete ΔT: Temperature rise value of concrete Qd: Heat supply amount of concrete C ^* : Unit amount of cement (amount of cement per unit volume)
V: Volume of filled container 5 The concrete temperature rise value ΔT is the difference from the concrete temperature at the time of placing. For example, if the concrete is poured at a temperature of 20.degree. The concrete temperature rise value ΔT is obtained as a function of the elapsed time t from the start of the measurement. As described above, since it takes a certain amount of time for the hydration reaction to start, the elapsed time after filling the filling container 5 with concrete may be defined as the elapsed time t. makes almost no difference.

The amount of heat supplied Qd is calculated from the heat flow densities measured by the first to third heat flow sensors 111-113. Since the heat flow density is the amount of heat that traverses a unit area per unit time, the heat supply Qd is, for example, the product of the average value of the heat flow densities measured by the first to third heat flow sensors 111 to 113 and the surface area of the filled container 5. It can be obtained by time integration (or as a time cumulative value of the product of the average heat flow density per unit time and the surface area of the filled container 5).

In this embodiment, the concrete is intentionally heated to prevent heat dissipation. Therefore, by correcting cρΔT/C ^* with Qd/C ^* /V (by subtracting Qd/C ^* /V from cρΔT/C ^* ), the actual accumulated heat generation amount Q can be estimated. That is, based on the amount of change in the first temperature T1, the approximate calorific value (cρΔT/C ^* ) of the concrete filled in the filling container 5 is obtained, and based on the heat flow density measured by the heat flow sensor, the amount of heat supplied to the concrete (Qd /C ^* /V), and correcting the approximate calorific value with the amount of heat supplied (approximate calorific value−the amount of heat supplied) to obtain the calorific value of the concrete.

Thus, in this embodiment, only the concrete is heated so that T2>T1. The hydration reaction of cement is temperature dependent, and it is possible that the hydration reaction process differs between complete adiabatic conditions and simple adiabatic conditions that allow heat dissipation. Since the hydration reaction rate increases with increasing temperature, the calorific value may be underestimated in simple adiabatic conditions that allow heat release. In other words, if the temperature drops due to heat dissipation, the hydration reaction rate of concrete will decrease, and there is a possibility that the accumulated heat value will be obtained in a state where the hydration reaction is not completely completed. If the calorific value decreases, the temperature-dependent hydration exothermic rate formula will be evaluated unsafely, and there is a possibility that pre-verification by temperature stress analysis of mass concrete structures will not be performed appropriately. In the present embodiment, heat radiation from the concrete is not allowed, so the temperature of the concrete can be maintained at a high level. As a result, the hydration reaction of concrete proceeds more rapidly, and the calorific value and temperature-dependent hydration exotherm rate equation can be evaluated on the safe side.

Since this embodiment only needs to heat concrete, the exothermic characteristic test apparatus 1 does not have means for cooling the internal space 31 . The test container 2 can be made compact because it does not require a refrigerator necessary for cooling, piping, or a pump for circulating the refrigerant. The outer dimensions of the test container 2 are, for example, about 500 mm in diameter and 650 mm in height, and most of the members are made of lightweight styrene foam. Since the filling container 5 is also unnecessary for transportation, the test container 2 is extremely light. The attachment jig 9, the temperature difference gauge 11, the thermometers 101-104, and the heat flow sensors 111-113, which are attached equipment, are also small and lightweight, and can easily be used for on-site measurement. Cost reduction is also possible because the configuration of the device is simplified. In a conventional high-performance test apparatus, precise control was required to match the second temperature T2 with the first temperature T1 as much as possible. No problem with control. Therefore, the control system can be simplified, and the calibration work of the test apparatus 1 can also be simplified.

In the formula for calculating the integrated heat generation amount, the correction based on the heat supply amount Qd can be omitted. Since the temperature difference T2-T1 is as small as about 1.0 degrees, the amount of heat supplied Qd is also limited. Therefore, there is no large error even if the accumulated heat generation amount Q=cρΔT/C ^* is obtained. Since this evaluation method can evaluate the calorific value on a larger scale, it is possible to evaluate the calorific value of concrete on the safer side.

In this embodiment, the evaluation of the calorific value of concrete (Step 4) can also be performed with a simple analysis. For example, the method described in Patent Document 1 requires inverse analysis using the finite element method, which requires a dedicated or general-purpose program, as well as requiring time and cost for analysis. In this embodiment, the calorific value of concrete can be calculated by a simple calculation using only the outputs of the thermometer and the heat flow sensor. The calculations can be satisfactorily performed on a general computer such as a PC installed on site. In the method described in Patent Document 1, it is necessary to grasp in advance the thermal characteristics of the device necessary for analysis, such as the thermal conductivity of the container, but this is not necessary in the present embodiment. In addition, since the method described in Patent Document 1 does not positively control the heat radiation characteristics, the heat radiation characteristics (insulation characteristics) may change greatly depending on the environmental temperature. Since the test apparatus 1 of this embodiment includes the seat heater 4 and controls the temperature difference T2-T1 to a predetermined target value, the influence of the environmental temperature is small.

REFERENCE SIGNS LIST 1 exothermic characteristic testing device 2 test container 3 heat insulating container 4 seat heater 5 filling container 6 outer container 7 inner container 11 control means (temperature difference gauge)
31 Internal space 101 to 104 First to fourth thermometers 111 to 113 First to third heat flow sensors P1 First position P2 Second position

Claims (9)

a heat insulating container having an internal space in which a filling container filled with concrete is installed;
a heating element circumferentially and planarly arranged in the inner space between a side wall of the heat insulating container and an installation area of the filling container;
a control means for controlling the heating element;
a first thermometer positioned inside the filling vessel;
a second thermometer disposed between the filling container and the heating element;
The control means obtains a temperature difference T2-T1 between the first temperature T1 measured by the first thermometer and the second temperature T2 measured by the second thermometer, and determines that the temperature difference is positive. An apparatus for testing heat generation characteristics of concrete, which controls the heating element so that 2. The apparatus for testing heat-generating properties of concrete according to claim 1, wherein said apparatus for testing heat-generating properties does not include means for cooling said concrete, and said temperature difference is controlled only by said heating element. 3. The apparatus for testing heat-generating characteristics of concrete according to claim 1, wherein said control means controls said heating element so that said temperature difference is about 0.5 to 1.5 degrees. 4. The apparatus for testing heat-generating properties of concrete according to any one of claims 1 to 3, further comprising a heat flow sensor arranged on the outer surface of said filling container. The thermal insulation container has an outer container and an inner container accommodated in the outer container, the outer container has a lower specific gravity than the inner container, and the inner container has a higher heat resistance than the outer container. 5. The apparatus for testing heat-generating properties of concrete according to any one of 4. placing the filled container filled with concrete in a test container with a heating element;
controlling the heating element by a control means when the concrete heats up;
The filling container is installed in the internal space of a heat-insulating container of the test container, and the heating element is circumferentially and planarly arranged between the side wall of the heat-insulating container and the installation area of the filling container,
A temperature is measured at a first location within the filling vessel and at a second location between the filling vessel and the heating element, and the controller controls the temperature measured at the first location. A method for testing heat generation characteristics of concrete, comprising obtaining a temperature difference T2-T1 between a temperature T1 and a second temperature T2 measured at the second position, and controlling the heating element so that the temperature difference is positive. 7. The method of testing heat-generating properties of concrete according to claim 6, wherein said test container does not have means for cooling said internal space, and said temperature difference is controlled only by said heating element. 8. The method for testing heat-generating properties of concrete according to claim 6, wherein said control means controls said heating element so that said temperature difference is about 0.5 to 1.5 degrees. measuring heat flow density into the filled vessel with a heat flow sensor located on the outer surface of the filled vessel;
obtaining an approximate calorific value of the concrete filled in the filling container based on the amount of change in the first temperature T1;
determining the amount of heat supplied to the filled container based on the heat flow density measured by the heat flow sensor;
9. The method for testing heat generation characteristics of concrete according to claim 6, further comprising: calculating a heat generation amount of concrete by subtracting said heat supply amount from said approximate heat generation amount.

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