高温后钢纤维混凝土的力学性能与微观结构  

Mechanical Properties and Microstructure of Elevated Temperatureprocessed Steel Fiber Reinforced Concrete

作　　者：董婧 杨进良 王炜 刘渊 杜娟 DONG Jing;YANG Jinliang;WANG Wei;LIU Yuan;DU Juan(Rocket Force University of Engineering,Xi’an 710025,China)

机构地区：[1]火箭军工程大学,陕西西安710025

出　　处：《火箭军工程大学学报》2025年第1期84-96,共13页Journal of Rocket Force University of Engineering

基　　金：火箭军工程大学青年基金资助项目(2022QN-B007)。

摘　　要：为研究不同温度作用对钢纤维混凝土力学性能与微观结构的影响,对比了经25℃、200℃、400℃、600℃温度处理后自然冷却的普通混凝土与体积掺量为1%的钢纤维混凝土的力学性能与微观结构。首先,通过混凝土立方体抗压试验及劈裂抗拉试验获取了试件的破坏形态、抗压强度、劈裂抗拉强度;然后,使用霍普金森压杆装置开展了4种冲击气压下试件的动态冲击压缩试验,获取了动态抗压强度与动态压缩增长因子,并运用扫描电镜观察了不同处理温度条件下试件的微观结构。研究结果表明:随着处理温度的升高,普通混凝土与钢纤维混凝土的颜色、表观裂纹、质量以及微观结构上均会产生变化,抗压强度与劈裂抗拉强度均呈降低趋势,且在400~600℃时出现了骤降;钢纤维的加入可以在一定程度上降低混凝土的高温后质量损失率,有效改善混凝土的动静态力学性能。此外,钢纤维的桥接作用可在一定程度上抑制混凝土裂纹的扩展。The effects of different temperatures on the mechanical properties and microstructure of steel fiber reinforced concrete(SFRC)was investigated by conducting a comparative study of the mechanical properties and microstructure of normal concrete(NC)that was naturally cooled after elevated-temperature treatment at 25℃,200℃,400℃ and 600℃,and SFRC with a volume proportion of 1%.First,the failure mode,compressive strength,and splitting tensile strength were obtained by compression and splitting tensile tests of a concrete cube.Second,the dynamic compressive strength and dynamic compression growth factors were obtained through dy namic impact compression tests,which were conducted on the specimens under four different impact pressures using Split Hopkinson Pressure Bar.The micro-structures of the specimens under different temperature treatments were observed using scanning electron microscope.Results showed that with an increase in temperature,both NC and SFRC change in terms of color,surface cracks,mass,and microstructure.Simultaneously,the compression and splitting tensile strengths show a decreasing trend,with a sudden drop at 400~600℃.However,the addition of steel fibers can reduce the mass-loss rate of concrete after high-temperature treatment,and effectively improve the dynamic and static mechanical properties of concrete.Additionally,the bridging effect of the steel fibers can inhibit the propagation of concrete cracks to some extent.

关 键 词：钢纤维混凝土 抗压试验 劈裂抗拉 霍普金森压杆 

分 类 号：TU528[建筑科学—建筑技术科学]