钢筋混凝土结构的电加速锈蚀技术研究-结构工程专业论文.docxVIP

烟 台 大 学 硕 士 学 位 论 文 II Abstract Various accelerated corrosion techniques have been adopted in the research of corroding reinforced concrete structures, which are different with natural corrosion. Three representative acceleration methods were employed in this work to corrode six concrete slabs, including full-immersion, half-immersion and wet-dry cycling. Based on the specimens, the developing of expansive cracks was investigated comparatively along with surface characteristic of corroded rebars. After the specimens had been corroded to the designed degree, expansive cracks were measured and recorded, then corroded bars were retrieved and cleaned from rusts. A three-dimensional laser scanning technique was used to build virtual models of those rebars through reverse engineering approach. Samples of corroded rebar segments with different lengths were taken from the models and their coefficients of nonuniform corrosion distribution, which is defined as the maximum cross-sectional area loss ratio divided by the average one over a segment, were calculated and denoted as R value. In addition, average corrosion area at the position of each measured expansive crack was determined to set up their correlation models. Shown by the results, R values obey generalized extreme value (GEV) distribution, and they are independent of corrosion degree for all the three accelerated corrosions. R value increases with sample length but is indistinctly influenced by rebar diameter, despite of the large scatter in case of small diameter. Half-immersion leads to maximal R values in general as well as relatively bigger scatters, which indicates higher nonuniform distribution of corrosion. Wet-dry cycling takes second place and full-immersion is the lowest. Expansive crack width increases linearly with the increasing of average corrosion area of corroded bars. A minimal degree of corrosion is required for half-immersion specimens to create an expansive crack of same width, which means more co