Indentation method for damage diagnosis of natural building stones

摘要

The indentation technique is tailored here to the needs of a method for in situ diagnosis of mechanical properties and damage of natural building stones. Indentation tests were performed in twelve natural building stones (chalks, limestones, sandstones, marbles) and mortars used for restoration. A wide range of mechanical and petrophysical properties with different failure mechanisms in indentation is thus represented. Indicatively, the Unconfined Compressive Strength (UCS) ranges between 3.1 MPa and 116MPa, and the tangent Young's modulus E_(50) at 50% of the maximum stress in uniaxial compression ranges between 0.9 GPa and 50 GPa. The tests were performed with three indenter diameters, 1-, 2- and 3-mm, to analyze scale effects in the results. The results are used to build correlation functions and databases between indentation parameters and stone stiffness and strength.