不同直径GFRP和BFRP筋高温后受剪与受压性能

Shear and Compressive Properties of BFRP and GFRP Bars with Different Diameters after Elevated Temperatures

通过高温后力学性能试验,研究了不同直径玻璃纤维增强复合材料(GFRP)筋和玄武岩纤维增强复合材料(BFRP)筋高温后受剪和受压性能。基于试验结果,分析了不同高温对不同直径GFRP筋和BFRP筋力学性能退化和破坏模式的影响。基于Weibull模型分析了GFRP筋和BFRP筋高温后抗剪强度和抗压强度的变异性。结果显示:GFRP筋和BFRP筋经历高温后形貌会发生明显变化,烧失量在300℃高温后快速增加,引起力学性能显著退化。GFRP筋和BFRP筋抗剪和抗压强度退化规律,以300℃高温为界分为两段,300℃后迅速退化且高温的影响程度显著高于直径的影响程度。抗压强度比剪切强度退化更为显著且变异性更高,直径越大的筋材力学性能退化越严重。所建立的强度概率模型和预测模型,与试验吻合较好,可以为相关分析提供参考。

Mechanical tests after high temperatures were performed to understand the influence of elevated temperatures on the shear and compressive properties of glass fiber reinforced polymer(GFRP)bars and basalt fiber reinforced polymer(BFRP)bars with different diameters.Based on the experimental results,the degradation of mechanical properties and failure modes of GFRP and BFRP bars were analyzed.Meanwhile,the Weibull model was utilized to reveal the variation of shear and compressive strengths of GFRP and BFRP bars after elevated temperatures.The results show that the high temperatures induced notable change in color and morphology of GFRP and BFRP bars.The ignition loss of both GFRP and BFRP bars experienced a remarkable increase after 300℃,which contributed to the significant degradation of mechanical properties.The pattern of degradation of shear and compressive strengths was divided by 300℃,after which temperature the strengths of GFRP and BFRP bars decreased sharply and the influence of the temperature was significantly higher than that of the bar diameter.The compressive strength of both GFRP and BFRP bars experienced more loss than the shear strength,and the corresponding coefficient of variation was larger.The bar with a larger diameter showed more degradation in both shear and compressive strengths after high temperatures.The probabilistic model and prediction model for strength of GFRP and BFRP bars were in good agreement with the experimental results,and could be used in related analysis.