混杂钢纤维超高性能混凝土梁裂缝分形理论研究

摘要/Abstract

摘要： 混凝土梁在受弯过程中表面裂缝分布及演化的宏观特征可以反映其受弯性能,本文基于不同废旧轮胎钢纤维(WTSF)取代率的玄武岩纤维增强复合材料(BFRP)筋混杂钢纤维超高性能混凝土梁受弯试验结果,利用分形理论分析试验梁表面裂缝开展情况。结果表明,BFRP筋混杂钢纤维超高性能混凝土梁表面裂缝分布具有分形特征,满足自相似性,分形维数的变化区间为[0.892,1.064]。探讨了梁表面裂缝分形维数与施加荷载值、WTSF取代率、跨中挠度和最大裂缝宽度之间的关系,并分别拟合了WTSF取代率与完全破坏状态下全梁区和纯弯段分形维数的函数关系。分形维数与施加荷载值、跨中挠度和最大裂缝宽度均呈对数函数关系,完全破坏状态下,WTSF取代率变大会增大梁表面裂缝的分形维数,但总体来说不利影响并不明显,研究结果可为超高性能混凝土的工程实际应用提供参考。

关键词: 超高性能混凝土, 分形维数, 废旧轮胎钢纤维, 工业钢纤维, 裂缝, 玄武岩纤维增强复合材料筋

Abstract: The bending performance of a concrete beam can be reflected by its macroscopic characteristicsof surface crack distribution and evolution during the bending process. The bending behaviors of concrete beams were investigated, and the fractal theory was applied to analyze the development of the surface cracks.Basalt fiber reinforced plastic (BFRP) bars reinforced ultra-high performance concrete with different waste tire steel fiber (WTSF) replacement ratios were used as the concrete matrix. The results show that the distribution of cracks on the surface of concrete beams exhibits fractal characteristics and self-similarity, the fractal dimension is between 0.892 and 1.064. The relationships between the fractal dimension of cracks on the surface of beams and the applied load, WTSF replacement ratio, mid-span deflection and maximum crack width were discussed, and the functional relationships between WTSF replacement ratio and the fractal dimension of the whole beam section and pure bending section under complete failure state were fitted, respectively. It is found that fractal dimension has logarithmic function relationship with applied load, mid-span deflection and maximum crack width. Under the complete failure state, the fractal dimension of cracks on the beam surface increases with the increment of WTSF replacement ratio, but the adverse effect is not obvious on the whole. The results obtained in this study can provide some theoratical basis and practical experiences for the application of ultra-high performance concrete.

Key words: ultra-high performance concrete, fractal dimension, waste tire steel fiber, industrial steel fiber, crack, basalt fiber reinforced plastic bar

中图分类号:

TU528

范小春, 葛腾, 梁天福. 混杂钢纤维超高性能混凝土梁裂缝分形理论研究[J]. 硅酸盐通报, 2022, 41(5): 1578-1588.

FAN Xiaochun, GE Teng, LIANG Tianfu. Fractal Theory of Cracks in Hybrid Steel Fiber Ultra-High Performance Concrete Beams[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2022, 41(5): 1578-1588.

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