竹纤维混凝土的动态力学性能研究

Study on dynamic mechanical properties of bamboo fiber reinforced concrete

用分离式霍普金森压杆(SHPB)装置对竹纤维混凝土(BFRC)进行了冲击压缩和动态劈裂试验。得到了2类试验下BFRC的主要力学参数,由此分析了该材料动态力学性能的特点。结果表明:①BFRC的抗压强度和劈裂强度均随应变率增加而显著增加,两者均可以采用幂函数关系反映动态强度增幅-动态增强因子(dynamic increase factor, DIF),但劈裂强度的应变率敏感性强于抗压强度。②压、拉2种应力状态下竹纤维对混凝土静态强度没有增强。高应变率下竹纤维对抗压强度动态增幅(DIFc)有小幅削弱,对劈裂强度动态增幅(DIFt)有显著增强。③高应变率压、拉两种应力状态下竹纤维均能有效改善混凝土脆性破坏特点,破损试样完整性更好,混凝土韧性提高。

Impact compression and dynamic splitting tests were carried out on bamboo fiber reinforced concrete(BFRC) by using a split-Hopkinson pressure bar(SHPB). The main mechanical parameters of BFRC under two kinds of tests were obtained, and the characteristics of dynamic mechanical properties of the material were analyzed. The results show that: 1) Both the compressive strength and the splitting strength of BFRC increase significantly with the increase of the strain rate, both of which can reflect the dynamic increase factor(DIF) by using the power function relationship, but the strain rate sensitivity of the splitting strength is stronger than that of the compressive strength. 2) The static strength of concrete was not enhanced by bamboo fiber under compression and tension.At high strain rate, the dynamic growth of bamboo fiber compressive strength(DIFc) was slightly decreased, while the dynamic growth of splitting strength(DIFt) was significantly increased. 3) Bamboo fiber can effectively improve the brittle failure characteristics of concrete under high strain rate compression and tensile stress, and the integrity of damaged samples is better, and the toughness of concrete is improved.