- 宿 輝，唐 陽，韓國松，汪 健，聶漢江
２０14年第10期
摘要
引用本文
摘 要：以建筑垃圾再生磚為研究對象，進行了單軸壓縮試驗，擬合了應力-應變曲線，采用掃描電鏡（SEM）對再生磚的細觀結構進行觀測，利用工業CT獲得了再生磚壓縮破壞過程中的裂紋分布特征，并借助分形理論進行分析裂紋演化特征。研究結果表明：建筑垃圾再生磚具有較大的孔隙率，存在諸多的初始缺陷，裂紋容易最先在這些薄弱環節出現。水泥石將骨料包裹起來形成筋絡結構可分割破壞區，延緩裂縫的伸展及匯聚過程，可有效提高再生磚的強度。同時再生磚具顯著的不均勻性，在荷載作用下不同斷面的分形維數的變化規律有較大的差異，斷面上平均強度越高，分形維數的變化越平緩，反之則變化要更劇烈，但整體物理性能與混凝土是相似的。CT和SEM結合可有效地對建筑材料的微觀結構和破壞機理進行分析，為進一步揭示再生磚的細觀損傷破裂機理奠定基礎。
Abstract: 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.
