基于SEM和ICT的建筑垃圾再生砖细观破坏机理  

Microscopic Damage Mechanism of Construction Waste Recycled Brick Based on SEM and ICT

作　　者：宿辉[1] 唐阳[1] 韩国松[1] 汪健[1] 聂汉江 

机构地区：[1]河北工程大学水电学院,邯郸056038

出　　处：《混凝土与水泥制品》2014年第10期93-97,共5页China Concrete and Cement Products

基　　金：河北省自然科学基金项目(E2010001034)

摘　　要：以建筑垃圾再生砖为研究对象,进行了单轴压缩试验,拟合了应力-应变曲线,采用扫描电镜(SEM)对再生砖的细观结构进行观测,利用工业CT获得了再生砖压缩破坏过程中的裂纹分布特征,并借助分形理论进行分析裂纹演化特征。研究结果表明:建筑垃圾再生砖具有较大的孔隙率,存在诸多的初始缺陷,裂纹容易最先在这些薄弱环节出现。水泥石将骨料包裹起来形成筋络结构可分割破坏区,延缓裂缝的伸展及汇聚过程,可有效提高再生砖的强度。同时再生砖具显著的不均匀性,在荷载作用下不同断面的分形维数的变化规律有较大的差异,断面上平均强度越高,分形维数的变化越平缓,反之则变化要更剧烈,但整体物理性能与混凝土是相似的。CT和SEM结合可有效地对建筑材料的微观结构和破坏机理进行分析,为进一步揭示再生砖的细观损伤破裂机理奠定基础。Based on the uniaxial compression test of construction waste recycled brick, the stress-strain curve was fitted, and the microscopic structure of recycled brick are observed by SEM. Crack distribution characteristics in the process of recycled brick compression failure were gained by using industrial computed tomography（CT）, and the crack evolution characteristics were analyzed by means of fractal theory. The researches indicate that： construction waste recycled bricks have larger porosity, it exists many initial defects in the recycled aggregates, in these weak links cracks easily appears first and face to internal development of the cement matrix. Aggregates are wrapped by the cement matrix and only to form the sinew structure of separable damage zone, the cracks extension and the convergence process are delayed, the strength of the recycled brick can be efficiently improved. Meanwhile, recycled brick has the inhomogeneity, it exists some differences that change rules of the fractal dimension about different cross section in the load condition are major, the average strength higher, the fractal dimension changes more gently, the opposite changes are more severe, but the overall physical properties and the deformation regularity of under uniaxial loading is similar with those of concrete; the microstructures of construction materials and failure mechanism are analyzed by CT and SEM, which lays a foundation for further revealing the microscopic damage fracture mechanism of the recycled brick.

关 键 词：建筑垃圾再生砖 扫描电镜 工业CT 筋络结构 分形理论 

分 类 号：TU522[建筑科学—建筑技术科学]