Device and method for measuring heat conductivity coefficient reduction rate of concrete in uniaxial compression process

Abstract

The invention discloses a device and a method for measuring the heat conductivity coefficient reduction rate of concrete in a uniaxial compression process. A concrete test sample is put into a bracket to be subjected to a compression load, and meanwhile a heating unit and a refrigerating unit establish a temperature difference between two planes of the concrete test sample; the bracket is used for fixing relative positions of the concrete test sample with the heating unit, the refrigerating unit, a heat insulating material and heat conduction silica gel; the concrete test sample is deformed under pressure, and extrudes the heat insulating material, the heat conduction silica gel, the refrigerating unit and the heating unit in order that the heat insulating material, the heat conduction silica gel, the refrigerating unit and the heating unit move outwards towards the periphery; peripheral support posts of the bracket are used for determining moving tracks of peripheral materials; spring pressing plates and springs on the support posts provide a proper peripheral pressure not influencing mechanics experiments in order to ensure that the refrigerating unit and the heating unit fit the surface of the concrete test sample, thereby reducing a contact thermal resistance as much as possible. Under the situation that the concrete test sample is under a certain compression load, a thermal flow density inside the concrete test sample reaches a steady state, and the temperature is distributed stably in a one-dimensional form in the concrete test sample.

Description

technical field [0001] The invention relates to a device for measuring the decrease rate of concrete thermal conductivity during uniaxial compression, belonging to the technical field of concrete construction. Background technique [0002] In the field of mass concrete engineering, the heat of hydration of cement, sudden changes in external temperature, and external loads on the structure may cause cracks in concrete. The existence of cracks will lead to a decrease in the thermal conductivity of concrete, which in turn affects the expansion of cracks. Therefore, it is extremely important to understand the influence of concrete cracking on thermal conductivity for thermal-mechanical coupling analysis and to prevent further crack expansion. However, at present, people do not have a quantitative understanding of the variation law of the thermal conductivity of damaged concrete, and there is no experimental device for studying the thermal conductivity of cracked concrete. For t...

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Although the transient method has the advantages of high efficiency and convenience, it is not suitable for the pres

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