摘要
为分析冻融循环作用下混凝土材料的静态力学性能,并探讨立方体试块轴向压缩破坏过程和形态,依据慢冻法试验标准开展了混凝土冻融循环试验,测定未冻融、冻融25次、冻融50次及冻融75次混凝土的单轴压缩应力应变曲线和劈裂拉伸强度;结合孔隙结构的电镜扫描图像分析其劣化成因;同时利用ABAQUS有限元软件及混凝土损伤塑性模型对混凝土立方体试块的轴向压缩破坏过程及破坏形态进行数值模拟.试验结果表明:混凝土抗压强度、弹性模量和抗拉强度随冻融循环次数的增加而降低,变形增大;冻胀作用导致混凝土内部结构疏松造成其宏观力学性能劣化;数值模拟表明,立方体试件在压缩过程中竖直方向缩短、水平方向膨胀,裂缝在产生最大拉伸应变的区域扩展并最终形成四角锥破坏形态.
In order to analyze the static mechanical properties of concrete materials and the failure process of cube specimens in uniaxial compression,the freeze-thaw cycles test of concrete were carried out under the conditions of freeze-thaw according to the test standard of slow freezing method.The uniaxial compressive stress-strain curve and split tensile strength of cube specimens were measured for none freezing-thaw,25 times freezing-thaw,50 times freezing-thaw and 75 times freeze-thaw concrete.Meanwhile,the cause of deterioration was analysed by combining the scanning electron microscopy image of the pore structure.Furthermore,ABAQUS finite element software and concrete damage plasticity model were used to simulate the uniaxial compression failure process and failure form of concrete cube test block.The test results showed that the compressive strength,elastic modulus and tensile strength of specimens decrease with the number of freeze-thaw cycles,while the deformation of specimens increasing.The pore structure of concrete became loose due to the frost-heaving during the freeze-thaw cycles,which resulted in the deterioration of mechanical properties.Numerical simulation showed that the cube specimens decreased vertically and expanded horizontally during uniaxial compression.The cracks expanded within the region where the principle strain occurred,and eventually formed a quadrangular pyramid failure mode.
作者
杨晓林
王根会
YANG Xiao-lin;WANG Gen-hui(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;School of Civil Engineering,Qinghai University,Xining 810016,China)
出处
《兰州交通大学学报》
CAS
2020年第3期13-18,共6页
Journal of Lanzhou Jiaotong University
基金
青海省科技计划项目(2016-ZJ-721)
甘肃省重大科技专项计划项目(19ZD2GA002)。
关键词
混凝土
冻融循环
压缩应力应变曲线
孔隙结构
混凝土损伤塑性模型
concrete
freeze-thaw cycles
compressive stress-strain curve
pore structure
concrete damage plasticity model
