混凝土分形特征研究的现状与进展

Current situation and development of concrete fractal characteristic

阐述了混凝土材料分形特征测试评价的重要性,介绍了国内外研究现状及目前获得的一些重要结论,对目前亟待解决的问题以及今后的发展方向进行了探讨。认为将分形理论与混凝土材料科学和工程技术有效结合,描述微观、细观层次下的精细结构与宏观层次下的力学行为和自相似特征是有效的。提出了混凝土材料分形学的研究重点在分形特征的测试与评价,只有建立在合理的测试评价的基础上,混沌分形学的作用才能有效发挥,混凝土分形特征的测试在水泥及其掺合料的粉体特征、硬化混凝土孔隙特征、混凝土材料的断裂特征、冻害损伤特征、混凝土骨料分布、碱集料反应裂纹、早期开裂和冻害后的裂纹等宏观分形特征以及显微结构分形特征等方面是成功的。此外,在新拌混凝土分形特征测试评价方面的描述很少,从混沌动力学特征角度研究的内容不多,在混凝土孔结构与渗透特征方面也有较大的研究空间。

The significance of test and evaluation of the concrete fractal characteristic is expatiated.The actuality and some mainly recent conclusions are introduced.The problems which want to settle at present and development direction in the future are discussed.Then ,the author thinks that using the fractal theory and concrete material science and engineering technique effectively,people can describe microstructure,ultrastructure and macroscopical mechanical behavior and self-similarity characteristic effectively.The author also regards that the test and evaluation must be the study emphaszed in concrete material fractal characteristic.So without scientific test and evaluation,chaos and fractal can not act effectively.Concrete fractal characteristic test is successful in macro fractal characteristic and microstructure,such as that powdery characteristic of cement and admixtures,pore characteristic of hardened concrete,crack characteristic of concrete,freezing damage characteristic,aggregates distribution of concrete,alkali-aggregate reaction cracks,early cracks and freezing cracks.Furthermore,there is a little description of fresh concrete fractal characteristic's test and evaluation and study by the chaos dynamics characteristic.So,there are large space in pore structure and penetrative characteristic.