Fracture Energy Dissipation Mechanism of Concrete
SourceMoiré interferometry was used to determine the crack opening displacements (COD) along a stably or dynamically propagating crack in three-point-bend concrete specimens. For stable crack growth studies, the measured COD together with applied loading was input to a finite element model of the specimen to determine directly the crack closure stress (CCS) versus COD relationship along the fracture process zone (FPZ) that trailed the crack tip. For dynamic crack growth studies, the COD data together with three strain gage data taken along the crack path were used in an inverse analysis to extract the CCS versus COD relationships using a dynamic finite element model of the fracturing specimen. Variations in energy release and dissipation rates with crack extension were determined and the FPZ was identified as the major energy sink in concrete fracture.