Characterization of Concrete in Mixed Mode Fracture Under Confined Conditions

Abstract

Although considerable research has been devoted to concrete fracture in recent years, cracking and fracture under confined conditions remain largely unstudied. From the theoretical/numerical viewpoint, some models have been proposed which advocate for the asymptotic mixed mode (mode IIa) with a second fracture energy independent and significantly higher than the traditional mode I energy [1,2]. In 1990, the Group of Mechanics of Materials of the School of Civil Engineering at UPC Barcelona (ETSECCPB-UPC), introduced the concept of asymptotic shearcompression mixed mode, or mode IIa, for frictional materials such as concrete, consisting of a shear (mode II) crack developing under very high compression level across the fracture plane, such that all dilatancy would be suppressed and the crack would become sensibly straight, cutting through heterogeneities such as aggregates and matrix (Carol and Prat [1], Carol et al. [2]).