FRACTURE-PROCESS ZONE FOR MIXED-MODE LOADING OF CONCRETE

A combined crack closure-shear transfer model of the fracture-process zone (FPZ) of concrete was developed through an interactive use of fracturetest data and finite element analyses of crack-line wedge-loaded, double-cantilever beam (CLWL-DCB) specimens subjected to additional diagonal compression loading. The diagonal compression loading caused the crack to veer in the diagonal direction. The numerical simulation of those mixed-mode-fracture results showed that the load-carrying capacity of the specimens was governed only by the crackclosure stress on the FPZ, because the initial direction for the cracks coincided with the minimum principal stress direction and that direction remained essentially the same until the maximum wedge load was exceeded. The effect of shear-transfer modeling was demonstrated by numerical simulation of published fracture-test data for eccentrically loaded, four-point-bend specimens. © ASCE.