Characterization of confined mixed-mode fracture in concrete

While considerable literature has been developed on tension-dominated fracture of concrete, fracture phenomena under confined conditions remain largely unstudied. In recent years, models have been proposed which incorporate an asymptotic mixed mode or “mode IIa” under shear-compression with a second fracture energy independent and significantly higher than the traditional https://www.w3.org/1998/Math/MathML" display="inline"> G f . In this paper, recent experimental work being developed within the group of Mechanics of Materials of ETSECCPB-UPC in order to elucidate the existence of such second mode of fracture and evaluate the associated fracture energy is described. The short cylindrical specimens with coaxial cylindrical notches employed are similar to those proposed by Luong (1990) . In the setup developed, this specimen is introduced in a large-capacity triaxial cell, protected with membranes and subject to different levels of confining pressure prior to vertical loading.