冲击荷载下纳米碳纤维混凝土的动态受压力学特性  

Dynamic Compressive Mechanical Properties of Carbon Nanofibers Reinforced Concrete under Impact Loading

作　　者：夏伟 许金余[1,2] 聂良学 王志航 黄哲 姚廒 XIA Wei;XU Jinyu;NIE Liangxue;WANG Zhihang;HUANG Zhe;YAO Ao(School of Aeronautical Engineering,Air Force Engineering University,Xi’an 710038,China;College of Mechanics and Civil Architecture,Northwest Polytechnic University,Xi’an 710072,China)

机构地区：[1]空军工程大学航空工程学院,西安710038 [2]西北工业大学力学与土木建筑学院,西安710072

出　　处：《材料导报》2021年第22期22063-22071,共9页Materials Reports

基　　金：国家自然科学基金(51208507,51378497)。

摘　　要：为探究纳米碳纤维混凝土的动态受压力学特性,本研究利用Φ100 mm分离式霍普金森压杆装置,分别对素混凝土及体积掺量为0.1%、0.2%、0.3%、0.5%的纳米碳纤维混凝土试件开展冲击压缩试验,对比分析了混凝土在5组不同应变率水平下混凝土的动态抗压强度、动态压缩变形和冲击韧性的变化特征。结果表明:各掺量下纳米碳纤维对混凝土动态抗压强度、动态压缩变形和冲击韧性均具有不同程度的增强作用。纳米碳纤维掺量为0.3%时对动态抗压强度的增强效果最佳;纳米碳纤维仅在0.2%掺量时对混凝土动态弹性模量表现为提升作用,其他掺量下反而使其动态弹性模量有所下降。素混凝土及纳米碳纤维混凝土的动态抗压强度、冲击韧性和动态弹性模量均随应变率水平的提高而逐渐增大,表现出显著的线性关系。动态峰值应变、极限应变虽整体上随应变率的上升呈递增趋势,但二者并不存在明显的线性相关性。适量纳米碳纤维的掺入能够发挥小尺寸效应及增强、阻裂作用,改善基体的微观结构,提升混凝土在冲击荷载作用下的动态受压力学特性。For the purpose of delving deep into the dynamic compressive mechanical properties of carbon nanofibers reinforced concrete,the plain concrete and concrete with four different fiber volume fractions(0.1%、0.2%、0.3%、0.5%)were developed,and the impact compression tests were conducted withΦ100 mm split Hopkinson pressure bar.The variation characteristics of dynamic compressive strength,dynamic compression deformation,impact toughness and dynamic elastic modulus of concrete under five different strain rates were compared and analyzed.The results show that the addition of carbon nanofibers can enhance the dynamic compressive strength,dynamic compression deformation and impact toughness of concrete,and when the content of carbon nanofibers is 0.3%,the best dynamic compressive strength is obtained.However,only when the content of carbon nanofibers is 0.2%,the dynamic elastic modulus of concrete is improved.The dynamic compressive strength,impact toughness and dynamic elastic modulus of plain concrete and carbon nanofibers reinforced concrete increase with the increase of strain rate,and show a significant linear relationship.Although the dynamic peak strain and ultimate strain increase with the increase of strain rate,there is no obvious linear correlation between them.Appropriate content of carbon nanofibers can play the role of reinforcement,crack resistance and small size effect,so as to improve the dynamic compressive mechanical properties of concrete under impact loading effectively.

关 键 词：纳米碳纤维 改性混凝土 冲击荷载 动态受压力学特性 应变率效应 

分 类 号：TU528.572[建筑科学—建筑技术科学]