The Influence of the Initial Concrete Strength on its Deformation under Triaxial Compression (original) (raw)

The results of the experimental research of the influence of the initial strength of С20/25, С30/40, С40/50, С70/85 concrete classes on the principles of linear, volumetric and shear strains development in the conditions of triaxial compression are introduced in this article. Experimental research techniques and realized loading programs are described. The program of the triaxial uniform hydrostatic compression in the conditions of 1 = 2 = 3 < 0 has been realized during the first stage of the experiment. The testing has resulted in defining the relation “mean stress 0 –relative volumetric strain change ” for relatively high levels of loading. The values of additional plastic strains of the relative volume change pl characterizing deviations of experimental strain values  from their design values according to the law of the elastic volume change el have been defined. However, higher values of pl correspond to lower strength concretes. The programs of non-uniform loading of the stress deviator at a mean stress invariable value (0 = const) have been realized during the second stage of the test. Experimental concrete specimens stress-strain curves in the directions of coordinate axes, diagrams of deviatoric stress and strain tensor components connection “i – i” as well as quantitative characteristics of the orthotropic concrete deformation process have been obtained. The determining influence of shear strains on dilatation effects in the concrete structure has been confirmed.