MECHANICAL-PROPERTIES OF CONCRETE IN UNIAXIAL COMPRESSION

Pre- and post-peak response phenomena are examined when cylindrical co ncrete specimens are loaded under deformation control in uniaxial comp ression. The experiments focus on degradation of stiffness and strengt h during unloading and reloading cycles, considering cylindrical speci mens of different height. Fracture energy concepts are used to interpr et the post peak response as a function of specimen height in order to extract a characteristic length measure. bl conclusion, the existence of a unique focal point (pole) is explored for the secant modulus des cription of elastic stiffness degradation and permanent (plastic) defo rmation.