MICROMECHANICS OF ITZ-AGGREGATE INTERACTION IN CONCRETE: CRACK INITIATION
Macroscopic crack initiation in concrete, defining the elastic limit of the material, starts around the aggregates in the region of the interfacial transition zones (ITZs) either by separation of cement paste from the aggregates or by microcracking inside the ITZs.In our multiscale model, concrete is considered to be a matrix-inclusion composite consisting of spherical coarse aggregates embedded in a mortar matrix, which, in turn, is represented as a matrix inclusion composite (on a smaller scale) consisting of sand grains embedded in a cement paste.At both scales, however, two-dimensional ITZs are considered to establish perfect bond between the inclusions and the surrounding matrix.At the scale of some micrometers, this ITZs are resolved as three-dimensional spherical shells.This three-scale approach is used to get access to microscopic interface tractions and ITZ stresses which are the basis for upscaling microscopic cracking functions for ITZ-aggregate separation and for ITZ failure, respectively, to the material scale of concrete.This paper reviews some major findings of the stress concentration and the related cracking characteristics, and also summarized sensitivity analyses and the comparison to experimental data.
Markus K(o)nigsberger Bernhard Pichler Christian Hellmich
Institute for Mechanics of Materials and Structures,Vienna University of Technology,Austria
国际会议
The Fourth RILEM International Symposium on Concrete Modelling (CONMOD 2014)(第四届RILEM混凝土材料建模国际会议)
北京
英文
215-221
2014-10-12（万方平台首次上网日期，不代表论文的发表时间）