摘要
混凝土广泛应用于核工程等基础建设领域,在其浇筑和凝固过程中,会在其内部产生类似币形或圆形等初始缺陷,实际上可通过改变椭球形的长、短轴来表征这些初始缺陷.为研究初始缺陷对混凝土拉伸力学性能及裂纹扩展的影响,本研究在混凝土试件中心处预置一个椭球形缺陷,采用劈拉试验获得拉伸强度,结合高速摄像机和引伸计采集裂纹的扩展过程.完整混凝土试件的拉伸强度为3.24 MPa,三类内置椭球形缺陷混凝土试件的拉伸强度分别为2.99 MPa、2.92 MPa和2.79 MPa.结果表明,混凝土的拉伸强度随着椭球形缺陷的增大而降低,内置的椭球形缺陷对本研究的裂纹两阶段扩展模式的影响不大.
Concrete is widely used in nuclear engineering and other infrastructure fields.In the process of pouring and solidification,initial defects such as coin shape or circular shape will appear in the concrete.In fact,the long and short axis of ellipsoid can be changed to characterize these initial defects.In order to study the effect of initial defects on the tensile mechanical properties and crack propagation of concrete,an ellipsoidal defect is preset in the center of the concrete specimen,and the tensile strength is obtained by splitting tensile test(also known as Brazilian disc test).The crack propagation process is collected by high-speed camera and extensometer.The tensile strength of the intact concrete specimen is3.24 MPa,and the splitting tensile strength of the three types of embedded ellipsoidal defect concrete specimen is 2.99 MPa,2.92 MPa and 2.79 MPa,respectively.The results show that the tensile strength of concrete decreases with the increase of the ellipsoidal defect;the ellipsoidal defects have little influence on the two-stage crack growth mode summarized in this paper.
作者
王杰
陶俊林
WANG Jie;TAO Junlin(Institute of Systems Engineering,China Academy of Engineering Physics,Mianyang 621900,China;School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China;School of Civil Engineering and Architecture,Southwest University of Science and Technology,Mianyang 621010,China)
出处
《成都大学学报（自然科学版）》
2021年第2期207-211,共5页
Journal of Chengdu University（Natural Science Edition）
关键词
混凝土
椭球形缺陷
劈拉试验
拉伸强度
concrete
ellipsoidal defect
splitting tensile test
tensile strength
