Test device and test method for determining early concrete thermal conductivity factor and thermal diffusivity

Abstract

The invention discloses a device which is used for determining the thermal conductivity and thermal diffusivity of early concrete, and a test method thereof. The determining device consists of a detachable steel test mold of 150mm multiplied by 150mm multiplied by 300mm, two resistance wires which are horizontally straightened, a connector, an ammeter, a direct-current voltage-stabilizing power supply, a thermistor, a high-precision temperature display instrument and a plurality of wires. The device has the advantages of simple structure, convenient disassembly, requirements for less materials and instruments, and high measurement accuracy. The device is not only suitable for scientific research, but also is applicable to the determination of the thermal conductivity and thermal diffusivity of early concrete on the construction site. Simultaneously, the device has a wide range of application, and can be used for measuring the thermal conductivity and thermal diffusivity of discrete materials, such as cement, sand and so on, and measuring the thermal conductivity and thermal diffusivity of clean slurry of cement and cement mortar.

Description

technical field [0001] The invention relates to a device and a testing method for simultaneously measuring early-stage concrete thermal conductivity and thermal conductivity, belonging to the field of concrete construction. Background technique [0002] In the field of civil engineering, it is very important to analyze the heat transfer of concrete structures. The heat of hydration released during the hardening process of concrete, or a certain degree of temperature gradient inside it, may lead to cracking of the concrete structure. In order to accurately predict the cracking trend of concrete under the action of these factors, and to prevent the occurrence of concrete cracking in time, it is necessary to systematically study the thermal conductivity, thermal conductivity and specific heat of concrete, especially in the early age of concrete. In the early stage, more in-depth research should be made on the changes of these thermal parameters with age. [0003] At present, ...

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Problems solved by technology

[0011] The hot wire method is widely used and can be used to measure the thermal conductivity of liquid substances. However, the hot wire method directly energizes and heats the hot wire. For liquid substances that can conduct electricity by themselves, in order to ensure that the passing electric energy is completely converted into heat energy, the hot wire must be insulated. In the hot wire method, in order to ensure the accuracy of the measurement, it is required that the hot wire should not be deformed and bent during the measurement process. At the same time, the measurement accuracy of the heating power and temperature of the hot wire is high. These factors increase the difficulty of the application of the hot wire method.

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