Читать книгу Monument Future - Siegfried Siegesmund - Страница 174

5 structure samples were collected from the stone surface (5 mm depth). Additionally, thin sections were done on those samples following the ASTM C1721 – 15, (2015) standard using blue epoxydic resin. Thin sections were petrographical analysed with an Olympus CX 31 microscope with magnifications ranging from x5 to x100 for assessing the presence of bioclasts, type of cement, terrigenous, distribution and quantification of primary and secondary porosity. Each thin section has a dimension of 4.5 cm × 2.6 cm. Point counting technique was used in a mesh of 300 equidistant points.

On these samples, ion analyses were carried out using Ion Chromatograph (IC). Powdered samples were dried at 60 °C until constant weight. Saline solubilisation was achieved by shaking 1 g of each dried sample in 100 ml of ultra-pure water. The 10 ml of obtained supernatants were filtered through a 0.2 µm PTFE membrane. The separation of cations Na+, Mg+, K+ was achieved by using a stationary-phase featuring a CS12A 250*4 mm column with a 10*4 mm guard (Dionex). As for anions Cl–, SO₄–, NO₃–, the stationary phase featured a AS9-HC 250 *4 mm column with a 10*4 mm guard (Dionex), (Nasraoui M. et al. 2009)the standard analytical equipment as ion chromatography (IC).

80 cubes of 5.0 × 5.0 × 5.0 cm were selected in the original quarry of the structure for the physical-mechanical 127characterization. Specimens were Characterized following the Natural Stone Test Methods (UNI EN 1936:2007 Natural stone test methods – Determination of real density and apparent density, and of total and open porosity, 2007). Real Volume V_R (m³), Open Porosity P_o (%) and Apparent Density ρ_b (kg m^–3) were calculated, (1–3).

Where m_d (g) is the Dry mass, m_s (g) Saturated mass, m_h (g) water immersion mass, ρ_rh water density at 20 °C, 998 kg m^-3.

Stone Uniaxial Compressive Strength (SUCS) measurements were done on the quarry samples.

X-Ray analysis were done in the 5 quarry samples and in 2 structure samples.