摘要
为探究玄武岩纤维混凝土在冻融环境中的损伤演化规律及裂纹特征,采用微机控制万能试验机系统,对冻融循环次数分别为0、5、10、15、20、25、30次的玄武岩纤维混凝土试样进行四点弯折试验。在进行损伤演化分析时,除采用相对动弹性模量和超声波波速这两个指标外,还利用“中性层位置”反映混凝土内部损伤;在对裂纹特征进行研究时,利用“相对角”概念定量分析裂纹变化规律。结果表明:在冻融作用下,试件的相对动弹性模量和超声波波速均呈减小趋势,中性层位置随着冻融循环次数的增加逐渐上移;裂缝在穿越骨料向前扩展时,出现了“一”字形扩展和避障扩展2种模式;随着冻融循环次数的增加,相对角呈现出3种不同的范围,对应于冻融的3个时期(未冻融、冻融早期、冻融后期),结合试件断面微观特征,得到了3个时期对应的3种破坏机理。研究成果对冻融作用下玄武岩纤维混凝土的损伤及断裂演化认知具有一定的参考价值。
In order to explore the damage evolution law and crack characteristics of basalt fiber reinforced concrete in freeze-thaw environment,the microcomputer-controlled universal testing machine system was used to conduct four-point bending tests on basalt fiber reinforced concrete samples with freeze-thaw cycles of 0,5,10,15,20,25,and 30 times,respectively.In the analysis of damage evolution,in addition to the two indexes of relative dynamic elastic modulus and ultrasonic wave velocity,the"neutral layer position"was used to reflect the internal damage of concrete.In the study of crack characteristics,the concept of"relative angle"was used to quantitatively analyze the variation law of cracks.The results show that under the action of freeze-thaw cycles,the relative dynamic elastic modulus and wave velocity of the specimen show a decreasing trend,and the position of the neutral layer gradually moves up with the increase of the number of freeze-thaw cycles.When the crack propagates forward through the aggregate,there are two modes of"one"shape expansion and obstacle avoidance expansion.With the increase of the number of freeze-thaw cycles,the relative angle presents three different ranges,corresponding to the three periods of freeze-thaw(non-freeze-thaw,early freeze-thaw,late freeze-thaw).Combined with the microscopic characteristics of the specimen section,the three failure mechanisms corresponding to the three periods are obtained.The research results have certain reference value for understanding the damage and fracture evolution of basalt fiber reinforced concrete under freeze-thaw action.
作者
李小双
肖定军
龙宇
章欣宇
裴广朝
韩森
LI Xiaoshuang;XIAO Dingjun;LONG Yu;ZHANG Xinyu;PEI Guangzhao;HAN Sen(School of Environment and Resource,Southwest University of Science and Technology,Mianyang Sichuan 621010,China)
出处
《化工矿物与加工》
2025年第6期29-36,共8页
Industrial Minerals & Processing
关键词
冻融循环
玄武岩纤维混凝土
相对动弹性模量
超声波波速
裂纹扩展
相对角
中性层
freeze-thaw cycle
basalt fiber concrete
relative dynamic elastic modulus
ultrasonic wave velocity
crack propagation
relative angle
neutral layer
作者简介
李小双(1998-),女,硕士研究生,E-mail:2968049781@qq.com;通信作者:肖定军(1982-),男,博士,副教授,硕士生导师,E-mail:dingjun@swust.edu.cn。
