基于细观结构性能和尺度的混凝土材料层次尺寸效应解析理论

The size effect of concrete in material-level is assumed to be attributed to the uncertainty of properties and scales of meso structures, including the coarse aggregates, the cement mortar and the interfaces. Firstly, the prediction method for the global mechanical properties of different graded concrete is modified through theoretical analysis, based on the established concrete mode-I fracture model that can take the meso structures into consideration. Secondly, an analysis theory for size effect of concrete in material-level is proposed and the variation of the global mechanical properties of concrete with properties and scales of meso structures is analyzed. The analysis shows that, the interface properties, the aggregate volume and the maximum aggregate size can significantly influence the percentage of interface cracks within the mesoscopic crack of concrete with strong aggregates under uniaxial tensile load, and, consequently the variation of the global mechanical properties of concrete with properties and scales of meso structures.