混凝土硫酸腐蚀表面形貌的分形维数表征

Surface Topography of Concrete After Sulfuric Acid Corrosion Characterized by Fractal Dimension

进行了混凝土的试验室硫酸加速腐蚀试验,运用三维激光扫描技术对6个不同腐蚀时间的混凝土表面形貌进行了数据采集,获得了每个试件表面上大量测点的三维坐标,采用立方体覆盖法编程计算了混凝土腐蚀表面的分形维数,并得到了分形维数与腐蚀时间、质量损失百分率、腐蚀深度之间的关系。结果表明,混凝土硫酸腐蚀后,其表面形貌具有分形特征,分形维数D可以作为混凝土硫酸腐蚀程度的一种评价指标,分形维数D与腐蚀时间t呈正相关,能用幂函数模型表示为D=1.954×t0.0228。混凝土试件的质量损失百分率ω和腐蚀深度h与其腐蚀表面形貌的分形维数D呈正相关,能分别用幂函数模型表示为ω=5.932×10-19×D57.333,h=5.045×10-20×D58.634,且可以用分形维数D通过这两个模型推断质量损失百分率ω和腐蚀深度h。

Accelerated concrete sulfuric acid corrosion test was conducted, surface topography of concrete specimens through 6 different corrosion time were scanned with 3D laser scanning techniques, 3D coordinates of the points on each cylinder surfaces were obtained. The fractal dimensions of the specimens were calculated with the cubic covering method. The relationship between fractal dimension and corrosion time, percent of mass losing, corrosion depth were explored. The test result shows the surface topography of concrete after sulfuric acid corrosion can be described by fractal dimension, which could be used as an evaluation indicator of corrosion degree. There was a positive correlation between fractal dimension and corrosion time, a power function model can be expressed as D=1. 954×t^0.0228. There were also positive correlations between fractal dimension and percent of mass losing, corrosion depth, power function models can be expressed as ω= 5. 932×10^-19×D^57.333, h = 5. 045×10^-20×D^58.634 respectively. Percent of mass losing, corrosion depth can be calculated with fractal dimension through the regression formulas.