利用X射线微型计算机断层扫描技术(Micro-XCT)进行钢筋的通电腐蚀行为及裂缝的三维分布研究

Study of 3D distribution of corrosion products and cracks in rebar reinforced system by micro-XCT

为了揭示钢筋混凝土结构中的钢筋腐蚀情况及裂缝的三维分布,采用无损检测技术中的X射线计算机断层扫描技术(Micro-X-ray computed tomography)对水泥净浆包裹的钢筋试件在微米尺度进行了三维重构和定量分析,研究了钢筋腐蚀产物与裂缝之间的关系,并将钢筋质量腐蚀率的实际值与理论值进行了对比。结果表明:X射线微型计算机断层扫描技术(Micro-XCT)能够从微米尺度反映水泥净浆试件中的钢筋腐蚀产物及裂缝的三维分布情况;裂缝的存在为氯离子进入钢筋表面提供了通道,是导致钢筋腐蚀的重要原因;分析计算所得钢筋质量腐蚀率的实际值与理论值较为符合。

Micro-X-Ray Computed Tomography technique was applied to reinforcement specimens wrapped with cement paste to explore corrosion of reinforcement and three-dimensional （3D） distribution of cracks in reinforced concrete structure. The obtained tomography results were used to reconstruct the specimens in a micrometer scale and for quantitative analyses. The relationship between corrosion product and generation of cracks was studied and the results were compared with theoretical values. The results show that the Micro- XCT technique can effectively reveal the corrosion product and the three-dimensi0n distribution of cracks in cement paste in a micrometer scale. Existence of cracks provides quick paths for ingress of chloride ions to reinforcement and is an important reason for corrosion of reinforcement. The results of corrosion rate detected in experiments are inconsistent with those obtained from theory.