| 陈厚群,丁卫华,蒲毅彬,党发宁.单轴压缩条件下混凝土细观破裂过程的X射线CT实时观测[J].水利学报,2006,37(9):1044-1050 |
| 单轴压缩条件下混凝土细观破裂过程的X射线CT实时观测 |
| Real time observation on meso fracture process of concrete using X ray CT under uniaxial compressive condition |
| 投稿时间：2005-11-04 |
| DOI： |
| 中文关键词: 混凝土 CT CT尺度裂纹 统计 体积压缩或增大 屈服 软化 |
| 英文关键词: concrete computed tomography(CT)technology crackin CT scale statistics condense or expansion of volume yield softening |
| 基金项目:冻土工程国家重点实验室开放基金(SKLFSE200401);国家自然科学重点基金(90510017);西安理工大学科技创新与特色研究计划项目(106-210402) |
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| 中文摘要: |
| 应用X射线CT对单轴压缩条件下混凝土的细观破裂过程进行了实时扫描观测，获得了混凝土试件内部CT尺度裂纹开裂、扩展、连通的全过程CT图像。分析混凝土试件各扫描断面大统计区域平均CT数变化，表明静力压缩条件下混凝土在强度峰值前的CT数呈均匀变化，表现为整体压密和扩容。小统计区域平均CT数变化则对裂纹萌生更敏感。对CT图像进行等密度分割，可以精确地显示裂纹萌生部位和扩展过程。CT图像显示,混凝土材料进入屈服阶段的现象是不同的CT尺度裂纹各自变形和扩展，裂纹发生部位在砂浆与骨料之间。进入软化阶段的现象是不同的CT尺度裂纹相互贯通。分析结果表明，非线性阶段CT尺度裂纹的扩展和变形对混凝土强度和变形有决定性影响。 |
| 英文摘要: |
| The real time scanning observation on meso scale evolution of fracture in concrete under uniaxial compressive condition is carried out by means of X ray computed tomography (CT) technology. The CT images of initiation and development of cracks as well as the links among cracks are obtained. The analyses on mean CT values in large statistical region of scanning layers show that under the condition
of static compression before the occurrence of peak strength the variation is even, which exhibits the condense or expansion of volume. The variation of mean CT values in small statistic region is more sensitive to the initiation of crack. The location of the crack initiation and the process of development can be precisely displayed by equivalent density cutting of CT image. The concrete enters the yield stage is due to the deformation and development of CT scale cracks, it happened to the regions between mortars and aggregates. When the cracks are linked up the concrete enters the stage of softening. It is concluded that the expansion and deformation of cracks in CT scale play decisive roles influencing the strength and deformation of concrete in nonlinear stage. |
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