冻融作用下玄武岩纤维混凝土动态压缩破坏与耗能特征研究  

Study on dynamic compression failure and energy dissipation characteristics of basalt fiber concrete under freeze-thaw

作　　者：李雄姿 肖定军[1] 蒲传金[1] 岳宝兵 龙宇 李小双 裴广朝 LI Xiongzi;XIAO Dingjun;PU Chuanjin;YUE Baobing;LONG Yu;LI Xiaoshuang;PEI Guangzhao(School of Environment and Resource,Southwest University of Science and Technology,Mianyang Sichuan 621010,China)

机构地区：[1]西南科技大学环境与资源学院,四川绵阳621010

出　　处：《化工矿物与加工》2024年第9期24-33,共10页Industrial Minerals & Processing

基　　金：陕西省混凝土结构安全与耐久性重点实验室开放基金项目(SZ02201)。

摘　　要：为探究玄武岩纤维混凝土在冻融循环境中的动态压缩破坏特征以及破坏耗能特性,采用φ50 mm分离式霍普金森压杆装置,对冻融循环次数为0次、10次、20次、30次玄武岩纤维混凝土试样分别进行冲击速度为7、11、15 m/s的冲击压缩试验。探讨了冻融循环次数和应变率对试样动态抗压强度、破碎耗能和碎块分形维数的影响,建立了动态抗压强度与冻融循环次数以及应变率的表达式,并对分形维数与冻融循环次数以及破坏耗能关系进行了分析,结果表明:增加冻融循环次数、增大冲击速度均会使试样的破坏程度加剧,且主要以劈裂拉伸破坏为主;降低应变率、增加冻融循环次数均会使玄武岩纤维混凝土的动态抗压强度降低,且在冲击速度为7 m/s、冻融循环30次时,其动态抗压强度降低率最高,为32.44%;冲击破碎后玄武岩纤维混凝土碎块具有统计意义上的分形维数,冻融循环次数的增加和应变率的增大均会造成碎块的平均粒径减小、分形维数增大;破碎耗能与冻融循环次数的变化规律与动态抗压强度一致;此外,破碎耗能与分形维数之间存在一定联系,同一冻融循环次数下,分形维数越大,破碎耗能越大;同一应变率下,分形维数越大,破碎耗能反而越小。In order to investigate the dynamic compression failure characteristics and energy dissipation characteristics of basalt fiber concrete under freeze-thaw cycles,adopt theφ50 mm split Hopkinson compression rod device was used to conduct impact compression tests on basalt fiber concrete specimens with 0,10,20,and 30 freeze-thaw cycles at impact speeds of 7 m/s,11 m/s,and 15 m/s,respectively.The effects of freeze-thaw cycles and strain rate on the dynamic compressive strength,crushing energy dissipation,and fractal dimension of basalt fiber reinforced concrete specimens were explored.Expressions for dynamic compressive strength,freeze-thaw cycles,and strain rate were established,and the relationship between fractal dimension,freeze-thaw cycles,and failure energy consumption was analyzed.The results show that increasing the number of freeze-thaw cycles and impact speed can increase the damage degree of basalt fiber concrete specimens,mainly in the form of splitting tensile failure;Reducing the strain rate and increasing the number of freeze-thaw cycles can both reduce the dynamic compressive strength of basalt fiber concrete,and the highest reduction rate of dynamic compressive strength is 32.44%when the impact speed is 7 m/s and the freeze-thaw cycle is 30 times;After impact crushing,basalt fiber concrete fragments have statistical fractal dimensions.The increase in freeze-thaw cycles and the increase in strain rate will cause the decrease in the average particle size of the fragments and the increase in fractal dimensions;The variation pattern of crushing energy consumption and the number of freeze-thaw cycles is consistent with the dynamic compressive strength.In addition,there is a certain connection between crushing energy consumption and fractal dimension.Under the same number of freeze-thaw cycles,the larger the fractal dimension,the greater the crushing energy consumption.Under the same strain rate,the larger the fractal dimension,the smaller the crushing energy consumption.

关 键 词：冻融循环 玄武岩纤维 混凝土 动态压缩性能 耗能特征 分形维数 冲击速度 应变率 

分 类 号：TU528.57[建筑科学—建筑技术科学]