活性粉末混凝土高温后冲击力学性能研究

摘　要：利用分离式Hopkinson压杆系统，采用铅片作为整形器，分别对常温下、400℃、600℃及800℃高温过火后的RPC试样进行单轴冲击压缩实验。研究高温后钢纤维对RPC材料动态力学性能及吸能特性的影响规律。结果表明，高温过火前后钢纤维对RPC均有增强和增韧的作用。高温后因RPC塑性流动性能的增强，导致钢纤维的增韧作用减弱。RPC动态抗压强度高温后损失的速率高于韧性指标。分析RPC材料冲击压缩过程的能量机制，发现钢纤维提高了RPC的能量吸收率，因此能量吸收能力也得到了增强。利用SEM扫描电镜，从RPC材料微观结构变化的角度分析了其高温后宏观力学性能降低的原因。

Impact mechanical properties of reactive powder concrete after exposure in high temperature

Abstract: Uniaxial-compression split Hopkinson pressure bar (SHPB) experiments were performed for reactive powder concrete (RPC) samples. Both the untreated specimens and after exposure in high temperature (400℃、600℃ and 800℃) concretes were tested in order to investigate the influences of mixed steel fibers on dynamic mechanisms and energy absorption for RPC concrete after exposure in high temperature. The results shows, steel fibers improve the strength and toughness of RPC before and after exposure in high temperature. After exposure in high temperature, due to a higher plastic flow property of PRC, the improved toughness effect attenuate. The compression strength losing ratio for RPC is higher than toughness parameter. Energy absorption ratio and energy absorption ability for RPC are improved by mixing steel fiber. And scanning electron microscope (SEM) technology is used to investigate the micro-structure change of the RPC material and a connection analysis between micro-structure and mechanical properties after burnt is discussed.