摘要:
采用Φ100 mm分离式霍普金森压杆 (SHPB) 试验装置研究了不同纤维体积掺量的玄武岩纤维混凝土在不同应变率下的冲击压缩力学性能 , 并对试验的有效性进行了分析。结果表明: 玄武岩纤维混凝土的动态强度增长因子与平均应变率的对数近似呈线性关系 , 强度与变形能力随平均应变率的提高而线性增加 , 体现了很强的应变率相关性 ; 纤维体积掺量为 0. 1 %的玄武岩纤维混凝土较素混凝土的动态抗压强度提高了 26 % , 变形能力提高了 14 %; 纤维体积掺量分别为 0. 2 %、 0. 3 %的玄武岩纤维混凝土的动态抗压强度比素混凝土高出 25 %左右 , 而变形能力较素混凝土无明显优势 ; 在玄武岩纤维混凝土的 SHPB试验中 , 试件破坏时刻为 123. 3～239.μ45 s , 近似恒应变率加载时间比例约为 62 % , 且应变率曲线的波动范围控制在 23 %左右 , 能够较好地满足应力均匀分布及恒应变率加载要求 , 表明 SHPB试验结果可靠。
Abstract:
The dynamic mechanical properties of the concrete reinforced with various volume f ractions of basalt fiber subjected to high strain rates were studied using split Hopkinson pressure bar ( SHPB) apparatus , and the
validity of experiment was analyzed. The test s reveal that the dynamic st rength and toughness of basalt fiber
reinforced concrete ( BFRC) are st rain rate dependent , the st rain rate effect can be expressed by linear
approximations , and the relationship between dynamic st rength increase factor and logarithm of average strain rate is approximately linear . The addition of 0. 1 % (volume f raction) basalt fiber result s in 26 % and 14 % increase of impact compressive strength and toughness , respectively. The addition of 0. 2 % and 0. 3 % basalt fiber result s in 25 % increase of impact compressive st rength and no significant superiority in toughness to plain concrete. During μSHPB test s , BFRC specimens begin to fail at 123. 3～239. 45 s , nearly constant st rain rates are obtained over 62% of test durations , and the average relative error of the st rain rate is 23 % , so the SHPB test result s of BFRC are credible.
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