THE DUCTILE BEHAVIOR OF HIGH PERFORMANCE CONCRETE IN COMPRESSION

The ductility of High Performance Concrete (HPC) can develop both in tension and compression. This aspect is evidenced in the present paper by measuring the mechanical response of normal vibrated concrete (NC), self-compacting concrete (SC) and some HPCs cylindrical specimens under uniaxial and triaxial compression. The post-peak behaviour of these specimens is defined by a non-dimensional function that relates the inelastic displacement and the relative stress during softening. Both for NC and SC, the increase of the fracture toughness with the confinement stress is observed. Conversely, all the tested HPCs, even in absence of confinement, show practically the same ductility measured in normal and self-compacting concretes with a confining pressure. Thus, the presence of HPC in compressed columns is itself sufficient to create a sort of active distributed confinement,and improve both the mechanical behaviour of concrete and its durability.