Estimate of the uniaxial compressive strength of sandstones, using Schimdt Hammer rebound number, in the Quarry situated in “Cerreto Alto” of Panicale (Italy).

This paper describes the results of a research work to estimate the uniaxial compressive strength of sandstones, using Schimdt hammer rebound number, in the quarry surface, situated in “Cerreto Alto” of Panicale (Italy). With Schimdt hammer rebound number, the measurements can be performed directly on the quarry surface and the compressive strength of rock can be estimated from the measured results with limited reliability. Surface hardness testing is a long-established non-destructive testing method for the strength estimation of rocks. Hardness testing was the first material testing practice from the 1600’s in geology and engineering by the scratching hardness testing methods; it is started in 1857 when David Kirkaldy, Scottish engineer set up the first material testing laboratory in London, Southwark. The theoretical hardness research was initialized by the pioneering work of Heinrich Hertz in the 1880’s. Hertz’s proposal also formed the basis of the indentations hardness testing methods by Brinell, 1900; Rockwell, 1920; Vickers, 1924 and Knoop, 1934. Since then, the Schmidt rebound hammer is the surface hardness testing device of most widespread use for the rocks in quarry because can be used very easily and the measure of hardness (i.e., the rebound index) can be read directly on the display of the testing device. Since the advantages and disadvantages of the device for measuring rock characteristics have become apparent, the Schmidt Hammer has been used for an increasing range of purposes, including the relationships between rock strength and landform. Readings of rock hardness have often been found to correlate well with other measures of rock character, such as uniaxial compressive strength and Young's Modulus of Elasticity.