UHPC直拉试验方法与本构关系研究  

Study on Uniaxial Tensile Test Method and Constitutive Relationship of UHPC

作　　者：杨简 李洋 陈宝春 徐港[1,2] 黄卿维 YANG Jian;LI Yang;CHEN Baochun;XU Gang;HUANG Qingwei(Hubei Key Laboratory of Disaster Prevention and Mitigation,Yichang 443002,Hubei,China;College of Civil Engineering&Architecture,China Three Gorges University,Yichang 443002,Hubei,China;College of Civil Engineering,Fujian University of Technology,Fuzhou 350116,China;College of Civil Engineering,Fuzhou University,Fuzhou 350108,China)

机构地区：[1]防灾减灾湖北省重点实验室,湖北宜昌443002 [2]三峡大学土木与建筑学院,湖北宜昌443002 [3]福建工程学院土木工程学院,福州350116 [4]福州大学土木工程学院,福州350108

出　　处：《材料导报》2024年第6期153-161,共9页Materials Reports

基　　金：国家级地方高校能源和环境材料化学学科创新引智基地(D20015);土木工程防灾减灾湖北省引智创新示范基地(2021EJD026);国家自然科学基金(51878178);湖北省博士后创新项目(Z2022177);防灾减灾重点试验室开放基金(4102/1640082)。

摘　　要：超高性能混凝土(Ultra-high performance concrete, UHPC)单轴拉伸(直拉)试验是分析UHPC抗拉性能和直拉本构关系的基础性试验,经过对其试件形状与尺寸的优化,试验成功率已得到了较大提升。但由于试件连接方式和局部加强方式的差异,各机构试验成功率参差不齐。为进一步保证直拉试验成功率,采用试验研究和数值模拟的方法系统分析了常见的四种试件连接方式和三种试件局部加强方式对试验成功率的影响,比选出最优试验方法。结果表明:面内夹持装置具有连接可靠、操作简单的优点,适合推广。但夹具的尺寸加工误差或微变形可能导致其与试件的接触面变窄、加剧夹持引发的试件应力集中,致使主裂纹位于测距范围之外;试件与夹具的接触区域进行柔性加强(粘贴碳纤维布)和刚性加强(粘贴铝片)均能有效解决上述问题,提高试验成功率。此外,采用比选的直拉试验方法,探究了钢纤维长径比和体积率对UHPC直拉损伤本构关系的影响。通过声发射(Acoustic emission, AE)监测探究了UHPC在直拉荷载作用下的损伤演化规律,利用声发射参数(累积计数比)构建损伤因子,得到了考虑钢纤维影响的UHPC直拉损伤本构关系。Uniaxial tensile test of ultra-high performance concrete(UHPC)is a basic material test to analyze its tensile properties and tensile constitutive relationship.Through optimization of the shape and size of the specimens,the success rate of the test has been greatly improved.Howe-ver,due to the difference in the connection device and reinforcement method,the success rate of each institution is uneven.In order to further ensure the success rate of the uniaxial tensile test,the influence of four common connection devices and three reinforcement methods on the success rate of the test were systematically analyzed through experimental research and numerical simulation,and the optimal test scheme was selected.The results showed that the in-plane clamping device has the advantages of reliable connection and simple operation,which is suitable for popularization.However,there is a problem that the size processing error or micro deformation of the clamp leads to the narrowing of the contact surface with the specimen,intensifies the stress concentration caused by clamping,and makes it impossible to control the main crack to be located in the measuring range;both flexible reinforcement(paste carbon fiber reinforced polymer)and rigid reinforcement(paste aluminum sheet)of the contact area between the specimen and the fixture can effectively solve the above problems,increase the success rate.In addition,the influence of the aspect ratio and volume fraction of steel fibers on the damage constitutive relationship of UHPC under uniaxial tension was investigated by using the optimal uniaxial tensile test method.The damage evolution law of UHPC under uniaxial tensile load was explored through acoustic emission(AE)monitoring.The damage factor was constructed using AE parameters(cumulative counts ratio),and the uniaxial tensile da-mage constitutive relationship of UHPC considering the influence of steel fiber was obtained.

关 键 词：超高性能混凝土 直拉试验 连接装置 加强方式 钢纤维特征参数 直拉本构关系 

分 类 号：TU528.58[建筑科学—建筑技术科学]