Effect of high temperature environment on degradation of tensile properties of GFRP bars in concrete

doi:10.19936/j.cnki.2096-8000.20250228.002

Abstract

Abstract: Tensile tests of glass fiber reinforced polymer (GFRP) bars embedded in concrete were carried out after high temperature. The variations of temperature difference between the inner and external locations of concrete specimen and the appearance changes of GFRP bars were analyzed. The degradation of tensile properties of GFRP bars was discussed and the prediction method of the tensile strength retention coefficient of GFRP bars in concrete after high temperature was proposed. The test and analysis results show that there is an obvious temperature lag phenomenon of GFRP bars placed in concrete. The temperature at the surface of GFRP bar can reach the operating temperature after about 2 h of heating in the furnace. The cover concrete can reduce the degree of looseness of the internal bars after high temperature and its protective effect on the tensile strength retention of GFRP bars is more obvious under the operating temperature of 300~350 ℃. When the operating temperature reaches 400 ℃, the tensile properties of GFRP bars decrease rapidly and the protective effect of cover concrete on the thermal insulation gradually weakens to disappear. Under the condition of 300 ℃, the constant temperature time has significant influence on the tensile strength of GFRP bars in concrete, but has little influence on its elastic modulus. Boltzmann’s function can be adopted to effectively predict the tensile strength retention of GFRP bars in concrete after high temperatures. The related research can provide references for the fire-resistant design of GFRP bars in concrete structures.

Key words: glass fiber reinforced composite (GFRP), high temperature environment, concrete, tensile property, prediction model

CLC Number:

TB332

LU Chunhua, LI Zhaohui, QI Zhonghao, ZHU Xuewu, XU Yifan. Effect of high temperature environment on degradation of tensile properties of GFRP bars in concrete[J]. COMPOSITES SCIENCE AND ENGINEERING, 2025, 0(2): 12-19.

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