冻融循环对钢纤维混凝土动力性能的影响研究  

Influence of freeze-thaw cycles on dynamic performance of steel fiber reinforced concrete

作　　者：周涛 熊小斌 李岩 ZHOU Tao;XIONG Xiaobin;LI Yan(Dam Supervision Center,State Power Investment Corporation Limited,Xi’an 710061,China;Faculty of Water Resources and Hydroelectric Engineering,Xi’an University of Technology,Xi’an 710048,China)

机构地区：[1]国家电力投资集团有限公司大坝管理中心,陕西西安710061 [2]西安理工大学水利水电学院,陕西西安710048

出　　处：《水资源与水工程学报》2021年第3期167-172,178,共7页Journal of Water Resources and Water Engineering

基　　金：国家自然科学基金项目(50779051)。

摘　　要：通过对冻融循环劣化后的钢纤维混凝土试件进行动态三轴压缩试验,分析了冻融循环及钢纤维掺量对混凝土轴向极限抗压强度、轴向峰值应变和应力-应变曲线的影响。结合扫描电子显微镜(SEM)分析冻融前后钢纤维混凝土的微观结构。目的在于探明冻融循环对钢纤维混凝土动态力学性能的影响规律,为寒冷地区钢纤维混凝土在实际工程中的应用提供理论参考。结果表明:增加冻融循环次数导致轴向极限抗压强度下降且100次冻融循环后下降速度明显增大,而轴向峰值应变基本呈线性增大。应变速率的增加导致轴向极限抗压强度增大且轴向峰值应变逐渐减小。冻融循环破坏了钢纤维混凝土内部结构,导致应力-应变曲线包围面积减小,钢纤维混凝土吸收能量的能力降低。钢纤维掺量对冻融劣化后混凝土动力性能影响较大,本试验中1%的钢纤维掺量下冻融劣化后混凝土最优。SEM微观结构揭示了钢纤维增强混凝土抗冻性的强化机理,以及过量掺入钢纤维对抗冻性的弱化机理,与宏观试验结果一致。The dynamic triaxial compression tests for steel fiber reinforced concrete(SFRC)subjected to freeze-thaw(F-T)cycles were conducted to analyze the effect of F-T cycles and steel fiber content on the axial ultimate compressive strength,axial peak strain and stress-strain curve of the SFRC.Moreover,the microstructure of the samples before and after F-T cycles were observed using a scanning electron microscopy(SEM)in order to explore the influence of F-T cycles on the dynamic mechanical properties of SFRC,and provide a theoretical reference for the application of SFRC in practical engineering in cold regions.It is found that the increase of F-T cycles resulted in the decrease of axial ultimate compressive strength,and the decrease rate increased significantly after 100 cycles,whereas the axial peak strain of SFRC increased linearly.The increase of the strain rate led to the increase of the ultimate compressive strength and the decrease of the axial peak strain.The area of the stress-strain curve was diminished and the energy absorption capacity of SFRC decreased because F-T cycles damaged the internal structure of the SFRC.The steel fiber content had a great influence on the dynamic performance of the concrete after F-T deterioration.In this test,the concrete with 1%steel fiber content performed the best.SEM microstructure illustrates the strengthening mechanism of SFRC frost resistance and the weakening mechanism of excessive steel fiber content,and the results are consistent with the macroscopic test.

关 键 词：钢纤维混凝土 动力性能 冻融循环 三轴压缩试验 微观结构 

分 类 号：TV431.3[水利工程—水工结构工程]