MECHANICAL PROPERTIES OF CONCRETE IN UNIAXIAL COMPRESSION

Pre- and postpeak response phenomena are examined when cylindrical concrete specimens are loaded under deformation control in uniaxial compression. The experiments focus on degradation of stiffness and strength during unloading and reloading cycles, considering cylindrical specimens of different height. Fracture energy concepts are used to interpret the postpeak response as a function of specimen height in order to extract a characteristic length measure. In conclusion, the existence of a unique focal point (pole) is explored for the secant modulus description of elastic stiffness degradation and permanent (plastic) deformation.