高温后玄武岩纤维增强混凝土的冲击变形特性

Impact Deformation Properties of Basalt Fiber Reinforced Concrete after Exposure to Elevated Temperatures

关键词:  玄武岩纤维增强混凝土  高温  分离式霍普金森压杆  冲击变形； 应变率效应

Key words:  basalt fiber reinforced concrete(BFRC)  elevated temperature  split Hopkinson pressure bar  impact deformation  strain rate effect

摘要:

采用100分离式霍普金森压杆系统,研究了不同温度作用后玄武岩纤维增强混凝土（BFRC）的冲击变形特性.结果表明:随着温度及加载速率的升高,BFRC的变形破碎程度增大,应力应变曲线表现出塑性特征；同一温度下,BFRC的峰值应变和均值应变随平均应变率的增大而增大,具有明显的应变率相关性；同一加载速率下,随着温度的升高,BFRC的峰值应变和均值应变呈上升趋势,峰值应变的应变率敏感性逐渐增强,但在200℃时,BFRC在较低加载速率作用下的均值应变较常温有所减小；掺入玄武岩纤维可以有效提升高温后BFRC的冲击变形能力,且纤维掺量（体积分数）为03%时,BFRC的变形优势最大,但当温度与加载速率较低时,BFRC的均值应变较素混凝土小.

Abstract:

The deformation properties of basalt fiber reinforced concrete(BFRC) after exposure to different temperatures and subject to impact loading were investigated by using a 100mm diameter split Hopkinson pressure bar(SHPB) apparatus. The experimental results indicate that with the rise of temperature and impact velocity, the crushing degree of BFRC becomes greater and stress strain curves exhibit plasticity features. Under the same temperature, the peak strain and average strain increase with increase of average strain rate with obvious strain rate dependency. Under a fixed impact velocity, an increase in temperature results in a larger peak strain and average strain and enhances the strain rate sensitivity of peak strain, but after exposure to 200℃, the average strain of BFRC under a lower impact velocity is lower than that at room temperature. The addition of basalt fiber can efficiently improve the deformation performance of BFRC after exposure to elevated temperatures, and the impact deformation capability of BFRC is the best with 03% basalt fiber(volume fraction), but under lower temperature and impact velocity, the average strain of BFRC is lower than that of plain concrete.