Abstract

Fiber-reinforced polymer (FRP) bars have been widely applied in civil engineering. This paper presents the results of an experimental study to investigate the tensile fatigue mechanical properties of glass fiber-reinforced polymer (GFRP) bars after elevated temperatures exposure. For this purpose, a total of 105 GFRP bars were conducted for testing. The specimens were exposed to heating regimes of 100, 150, 200, 250, 300 and 350 °C for a period of 0, 1 or 2 h. The GFRP bars were tested with different times of cyclic load after elevated temperatures exposure. The results show that the tensile strength and elastic modulus of GFRP bars decrease with the increase of elevated temperature and holding time, and the tensile strength of GFRP bars decreases obviously by 19.5% when the temperature reaches 250 °C. Within the test temperature range, the tensile strength of GFRP bars decreases at most by 28.0%. The cyclic load accelerates the degradation of GFRP bars after elevated temperature exposure. The coupling of elevated temperature and holding time enhance the degradation effect of cyclic load on GFRP bars. The tensile strength of GFRP bars after elevated temperatures exposure at 350 °C under cyclic load is reduced by 50.5% compared with that at room temperature and by 36.3% compared with that after exposing at 350 °C without cyclic load. In addition, the elastic modulus of GFRP bars after elevated temperatures exposure at 350 °C under cyclic load is reduced by 17.6% compared with that at room temperature and by 6.0% compared with that after exposing at 350 °C without cyclic load.

Highlights

  • As a new type of structural material in civil engineering, fiber-reinforced polymer (FRP) has become an important supplement to traditional materials in civil engineering due to its excellent mechanical, physical and chemical properties [1,2,3]

  • Fiber-reinforced polymer (FRP) composite materials in civil engineering mainly include four categories based on the form of application: FRP strengthened structures, FRP ribs and cables to replace steel bars and steel cables, FRP combined with traditional materials and full FRP structures [4,5,6,7,8]

  • The experimental results showed that the elastic modulus and tensile strength of CFRP tendons decreased by 14% and

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Summary

Introduction

As a new type of structural material in civil engineering, fiber-reinforced polymer (FRP) has become an important supplement to traditional materials in civil engineering due to its excellent mechanical, physical and chemical properties [1,2,3]. The experimental results showed that the elastic modulus and tensile strength of CFRP tendons decreased by 14% and. The results showed that the FRP bars suffered significant reductions in their mechanical properties upon exposure to high temperatures of up to 450 ◦ C at which the GFRP and BFRP was melted and lost their total tensile strength capacity. The fatigue behaviors of GFRP bars (including tensile strength, elastic modulus, and failure modes and so on) were considered to be investigated after elevated temperatures exposure. The outcome of this investigation can be used by future researchers and engineers for evaluating fire resistance of concrete structural members reinforced with GFRP bars when subjected to elevated temperatures

Test Equipment
Experimental Design
Preparation of Specimens
Experiment Method
The Appearances of GFRP Bars after Elevated Temperatures Exposure
Appearances
Fatigue Failure Characteristics
Effect of Elevated Temperature
Tensile
Influence
10. The tensile strength strength of of GFRP
Influence of Cyclic Load on the Elastic Modulus of GFRP Bars
Conclusions
Full Text
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