3D surface image analysis for fracture modeling of cement-based materials

The texture and exposed phases of a fracture surface are direct evidence of the mechanical behavior of a cement-based material. Deflection, microcracking and bridging are toughening mechanisms involved in fracture of brittle matrices that affect surface roughness. This study measures crack deflection and branching using 3D surface measurement techniques with confocal laser microscopy of mechanically fractured mortar prisms and 3D stereo pair microscopy of mechanically fractured plain concrete prisms. Image analysis techniques were used to identify phase composition and out-of-surface crack branching from profiles of cracks intruded with a low melting-point alloy. The resulting data was the basis for a micromechanical model to relate surface and phase data and the measured fracture energy to the increase in energy with respect to fracture of the matrix independent from the composite behavior.