The use of Knoop indentation for the assessment of the elastic properties of mortars and natural stones

• Reasonably good values of E can be obtained from Knoop indentation tests.
• Heavy loads create subsurface fragmentation phenomena that alter the values of E.
• Very small loads create inappropriately small imprints to be measured.
• It is proved that elasticity parameter α=0.45 makes the results close to actual values.
• Surface preparation of very porous materials must be further investigated.