JP2009168528A - Loading and heating apparatus for concrete test piece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a loading and heating apparatus for a concrete test body capable of stably heating the concrete test body and uniforming the distribution of heating temperature in order to precisely evaluate high temperature properties of concrete. <P>SOLUTION: Heating media 2a, 2b enclosing upper and lower pressing jigs 1a, 1b respectively and indirectly heating a concrete test body C by the pressing jigs 1a, 1b and a heating medium 2c enclosing the central concrete test body C and directly heating the concrete test body C are provided inside a heating furnace 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a concrete specimen loading heating apparatus for obtaining a sample used for evaluating the mechanical properties of high temperature heated concrete in designing the fire resistance performance of a reinforced concrete structure.

  2. Description of the Related Art Conventionally, there has been proposed a concrete specimen heating apparatus in which a metal heater for heating a concrete specimen is arranged on the inner bottom side of a heat insulating container, and fans for arranging the temperature distribution in the container are arranged vertically. (Patent Document 1).

However, a long heating time is required from the point where it is difficult to heat evenly by placing a metal heater on the inner bottom side of the heat insulating container because the heat transfer coefficient of concrete is inherently small and uniform heating is difficult. For this reason, the temperature distribution difference by the dimension of a concrete test body is large, and it is difficult to evaluate clearly the high temperature characteristic and mechanical property of the concrete which received high temperature.
JP 2006-118996 A

  An object of the present invention is to provide a load heating device for a concrete specimen that can stably heat the concrete specimen and make the heating temperature distribution uniform in order to accurately evaluate the high temperature characteristics of the concrete.

  In the present invention, in order to obtain a sample for evaluating the high temperature characteristics of concrete, a concrete test specimen embedded with a thermocouple is held by the upper and lower pressure jigs and accommodated in the heating furnace, and the high temperature is obtained in the heating furnace. In a concrete specimen loading heating apparatus for heating and analyzing the temperature distribution state of a concrete specimen, a heating medium that indirectly heats the concrete specimen from the pressure jig by surrounding the upper and lower pressure jigs, respectively A heating medium surrounding the central concrete specimen and directly heating the concrete specimen is provided inside the heating furnace.

  In the configuration of the concrete specimen load heating device, a metal heater can be provided as the upper, lower, and center heating media. Further, the metal heater can be used as the upper and lower heating media, and a metal frame having a large heat transfer coefficient can be sandwiched between the upper and lower metal heaters and arranged as the central heating media, and the metal heaters can be individually controlled.

  According to the concrete specimen load heating device of the present invention, the concrete specimen is heated indirectly from the pressing jig and the concrete specimen is directly heated, so that the concrete specimen can be stably heated, The heating temperature distribution can be made uniform in a short time.

  In addition, since the metal heaters are individually provided so as to be controllable, they can be used together to obtain a sample used for evaluating the mechanical properties of the concrete heated at a high temperature from various viewpoints.

  In the illustrated embodiment, as shown in FIG. 1, heating media 2a and 2b for surrounding the upper and lower pressure jigs 1a and 1b and indirectly heating the concrete specimen C from the pressure jigs 1a and 1b, A load capable of heating the concrete specimen C at a working temperature of 100 to 800 ° C. by providing a heating medium 2 c surrounding the central concrete specimen C and heating the concrete specimen C directly in the heating furnace 3. It is configured as a heating device.

  The pressurizing jigs 1a and 1b are made of carbon steel that has been heat-treated to withstand high temperatures under a load of 2000KN or more. Among the pressurizing jigs 1a and 1b, the lower pressurizing jig 1b mounts the concrete test body C and is installed so as to be movable up and down toward the upper pressurizing jig 1a. Each pressurizing jig 1a, 1b is provided with a water-cooled cooler (not shown) so that the temperature does not rise above 50 ° C.

  A metal heater 20 is provided as the heating media 2a to 2c. The metal heater 20 is formed by winding a coil, and the surface of the metal heater 20 is embedded and attached to the coil holder 21 facing the pressure jigs 1a, 1b or the concrete test body C. Surrounding the heating media 2a to 2c, a ceramic fiber blanket 22 is loaded in the furnace as a heat insulating material so as to prevent heat from being released outside the furnace.

  As shown in FIG. 2, the heating furnace 3 is configured to include a two-divided cylindrical ceramic fiber embedded heater including a metal heater 20, a coil holder 21, and a ceramic fiber blanket 22. A wheel 5 capable of traveling on the rail 4 with one side 3a as a fixed side and the other side 3b as a movable side is provided at the lower part of the heating furnace 3 (see FIG. 1). It is configured for the side.

  In the concrete specimen loading heating device configured as described above, the concrete specimen is indirectly heated by the pressurizing jig and the concrete specimen is directly heated, so that the concrete specimen can be stably heated. The heating temperature distribution can be made uniform in a short time.

  On the other hand, when the direct heating method using only the central heating medium is used, the heating rate is high, but the surface of the concrete specimen may be overheated and the concrete specimen may be damaged. According to only the indirect heating method with the upper and lower heating media, the concrete specimen is less damaged than the direct heating method, but the heating rate is slower.

  In addition to the embodiment described above, the metal heaters 2a and 2b are used as upper and lower heating media, and a metal frame (ring) 2c having a large heat transfer coefficient such as iron is sandwiched between the upper and lower metal heaters 2a and 2b as a central heating medium. You may arrange. Moreover, in order to obtain the sample used for evaluating the mechanical characteristics of the concrete heated at a high temperature from various viewpoints, the metal heaters 2a, 2b, and 2c can be individually provided to be controllable.

  By a test using only the direct heating method with the central heating medium, the surface part is prepared for explosion due to overheating from the central part of the concrete specimen, and a heat-resistant steel shielding cylinder is provided between the concrete specimen C and the heating media 2a to 2c. You can In addition, a voltage feedback thyristor regulator that adjusts the temperature of the heater can be provided.

It is a side view which shows the concrete test body loading heating apparatus which concerns on this invention. It is a top view which shows the concrete test body loading heating apparatus of FIG.

Explanation of symbols

C Concrete specimen 1a, 1b Pressure jig 2a-2c Heating medium 3 Heating furnace

Claims (4)

In order to obtain a sample for evaluating the high temperature properties of concrete, a concrete specimen embedded with a thermocouple is held by the upper and lower pressure jigs and housed in the heating furnace, and heated at a high temperature inside the heating furnace. In the concrete specimen loading heating device for analyzing the temperature distribution state of the specimen,
A heating medium that surrounds the upper and lower pressure jigs and heats the concrete specimen indirectly from the pressure jig, and a heating medium that surrounds the central concrete specimen and heats the concrete specimen directly A concrete specimen loading heating device provided inside a furnace.   2. The concrete specimen loading heating apparatus according to claim 1, wherein the metal heater is provided inside the heating furnace as a heating medium in the vertical and central directions.   The concrete specimen loading heating device according to claim 1, wherein the metal heater is used as an upper and lower heating medium, and a metal frame having a large heat transfer coefficient is disposed between the upper and lower metal heaters as a central heating medium.   The concrete specimen loading heating device according to claim 2 or 3, wherein the metal heater is provided so as to be individually controllable.

Images