Investigation of the Leeb hardness test in rapid characterisation of rock cores with particular emphasis on the effect of length to diameter ratio

Abstract

ABSTRACT The Leeb hardness is a practical, economical and non-destructive test method in rock characterisation in engineering. Hardness measurements on core samples with lower values of length-to-diameter (L/D) ratios cause unstable measurements, and as a result, erroneous evaluations can be made. To overcome this limitation, this study aimed to reveal the effect of different L/D ratios both in axial and diametral measurement directions. Eleven types of rock samples were prepared and tested. Mineralogical and petrographic examinations were performed and evaluated together with the hardness values. Equations have been proposed to estimate correct hardness and uniaxial compressive strength values for all rock types.