Experimental study of the size- and shape-effects of natural building stones

The dependence of the mechanical properties of natural building stones on the size and the shape of the specimens is studied experimentally. Attention is focused to the Kefalonia porous stone, a candidate substitute of the Kenchreae porous stone used by ancient Greeks for the erection of the Epidaurean Asklepieion. Series of uniaxial compression tests were carried out using both cubic and cylindrical specimens of various sizes. A number of mechanical properties were determined including the peak stress, the modulus of elasticity, the stress drop after the peak stress, the peak strain and the strain energy density up to the peak load. A strong dependence of the above properties on both the dimensions and the shape of the specimens was concluded. In addition, it was indicated that the dependence of some of the above properties on the size of the specimens is not monotonous. The conclusions drawn are in good agreement with similar ones obtained for Dionysos marble, the material used today for the restoration of the Parthenon temple of Athens as well as for the “Conchyliates” shell-stone the material that has been used for the construction of the Zeus Temple at Olympia.