活性粉末混凝土的层裂性能研究

THE SPALLING BEHAVIOUR OF REACTIVE POWDER CONCRETE

采用60%的超细工业废渣取代水泥制备了一种生态型的活性粉末混凝土(RPC),采用分离式霍普金森压杆装置对不同纤维掺量的RPC材料进行了层裂性能实验。研究得出了入射波强度和冲击次数对层裂过程中应力波传播的影响规律。按一维弹性波理论编写了入射压缩波和反射拉伸波在试件自由端附近相互作用的程序,计算出试件自由端附近拉应力的分布,由试件的层裂位置得到材料的层裂强度。结果表明,随着入射波强度的增加和冲击次数的提高,材料的拉伸损伤逐渐增加,反射拉伸波的强度逐渐降低。RPC材料层裂强度和破坏形态具有明显的应变率效应,层裂强度和破坏程度随着应变率的提高而增加。通过纤维的增强作用,层裂裂缝的宽度和深度都降低了。

Reactive powder concrete （RPC） is prepared by replacing 60% of the cement with ultra-fme industrial waste powder. The spalling behaviour of RPC with different fiber volume fractions is studied using split Hopkinson pressure bar （SHPB）. The effects of incident waves and impact times on the stress wave propagation are investigated. The program to calculate the interaction between compressive and tensile waves was developed based on one-dimensional elastic wave theory, and it was used to obtain the tensile stress distribution near the free side of the specimen. The spalling strength of the material is obtained according to the spalling position and the tensile stress distribution. The strain rate effects on spalling strength and fracture patterns are examined. Results show that （1） the amplitude of the reflective tensile wave decreases with the increase of the amplitude of the incident wave and impact times; （2） with the increase of strain rate, the spalling strength of RPC is enlarged and its fracture degree increases; （3） the depth and width of cracks on spalling diminish by the introduction of fiber reinforcement.