Brittleness determination of rocks by different methods

The term brittleness is used differently by different authors. An analysis is made in the present paper of the various concepts of it. The various phenomena associated with brittle substances, e.g. low value of elongation, fracture failure, formation of fines, higher ratio of compressive to tensile strength, higher angle of internal friction, formation of cracks in indentation, etc., can be used for measuring brittleness. Experimental results based on the measurement of some of the above quantities to represent brittleness have been presented. A discussion is made to compare the results of different formulation. It appears that there is no uniformity in different formulation of brittleness, e.g. brittleness based on strain ratio, brittleness based on energy ratio, brittleness from Mohr's envelope, brittleness from compressive and tensile strength, brittleness from Protodyakonov Impact Test, brittleness from macro- and micro-hardness, etc. Each concept of brittleness should, therefore, be treated and used separately with reference to its practical utility.