Protchenko Kostiantyn
Department of Civil Engineering, Warsaw University of Technology, 16 Armii Ludowej Av., 00-637 Warsaw, Poland.
Materials (Basel). 2022 Feb 17;15(4):1509. doi: 10.3390/ma15041509.
The fire resistance of fiber-reinforced polymer reinforced concrete (FRP-RC) elements depends on the temperature performance of the original concrete member, the fire scenario, and FRP reinforcement behavior. In this study, fire resistance tests are described, along with the characteristics obtained during and after applying elevated temperatures, simulating the effects of fire. The tested beams were reinforced with basalt (BFRP) bars and with a hybrid composite of carbon fibers and basalt fibers (HFRP) bars. Fire tests were performed on full-scale beams, in which the midsections of the beams were heated from below (tension zone) and from the sides for two hours, after which the beams were cooled and subjected to flexural testing. BFRP-RC beams failed before the heating time was completed; the best failure was associated with a BFRP reinforced beam that failed approximately 108 min after heating. Contrary to the BFRP-RC samples, HFRP-RC beams were capable of resisting exposure to elevated temperatures for two hours, but showed a 70% reduction in strength capacity when compared to non-heated reference beams. According to the author, the higher resistance of HFRP-RC beams was the result of the thermal expansion coefficient of carbon fibers employed in HFRP, which "prestresses" the beams and enables smaller deflections. The preliminary findings of this study can increase the feasibility of using FRP materials for engineering purposes.
纤维增强聚合物增强混凝土(FRP-RC)构件的耐火性取决于原始混凝土构件的温度性能、火灾场景以及FRP增强材料的性能。在本研究中,描述了耐火性测试,以及在施加高温期间和之后获得的特性,模拟了火灾的影响。测试梁用玄武岩(BFRP)筋和碳纤维与玄武岩纤维的混合复合材料(HFRP)筋进行增强。对全尺寸梁进行了火灾测试,其中梁的中部从下方(受拉区)和侧面加热两小时,之后梁冷却并进行弯曲测试。BFRP-RC梁在加热时间结束前就失效了;最好的失效情况是一根BFRP增强梁在加热后约108分钟失效。与BFRP-RC样本相反,HFRP-RC梁能够承受两小时的高温暴露,但与未加热的参考梁相比,其强度能力降低了70%。据作者称,HFRP-RC梁较高的耐火性是HFRP中使用的碳纤维热膨胀系数的结果,该系数使梁“预应力”并减小了挠度。本研究的初步结果可以提高FRP材料用于工程目的的可行性。