Põhja- ja Kesk-Eesti karbonaatkivimite kivimmehaanilised omadused ja nende varieeruvus [Magistritöö. Juhendaja: B. Grafe]

This master's thesis investigates the mechanical and physical properties of carbonate rocks in Northern and Central Estonia and their variability across different stratigraphic units. Carbonate rocks form a significant part of the Estonian bedrock and represent an economically important mineral resource, widely used as raw material for construction aggregate, road construction and the concrete industry. Despite the detailed knowledge of the geological structure of these rocks, the systematic characterisation of their mechanical and physical properties has remained limited in Estonia — existing data are fragmented and collected on varying methodological bases, which hampers comparison between different localities and stratigraphic units. Rock samples were collected from three active limestone quarries: Väo V (Middle Ordovician), Reinu (Upper Ordovician) and Lubja (Lower Silurian). Laboratory tests were carried out on samples representing 13 distinct stratigraphic units, including determination of uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), abrasivity using the CERCHAR method, ultrasonic wave velocities and Poisson's ratio, as well as mineralogical and chemical composition using X-ray diffraction (XRD) and X-ray fluorescence (XRF). Mechanical tests were conducted in three different sample orientations to assess the potential anisotropy of the rocks. The results indicate that the mechanical and physical properties of the studied carbonate rocks vary considerably across stratigraphic units and quarries, and are closely related to the mineralogical composition and microstructure of the rocks. A moderate positive correlation was observed between UCS and the CERCHAR abrasivity index, whereas mineralogical composition alone proved insufficient for reliably predicting abrasivity. The relationship between UCS and P-wave velocity was weaker than typically reported in international literature, suggesting that general empirical correlations may not be directly applicable to Estonian carbonate rocks. The drilling orientation of the test specimens had a measurable effect on several parameters, suggesting anisotropy induced by rock layering. The findings contribute to building a unified and comparable dataset on Estonian carbonate rocks, with practical value in mining, construction and geotechnical applications. Keywords: carbonate rocks, limestone, dolostone, rock mechanics, compressive strength, tensile strength, abrasivity, Ordovician, Silurian, Estonia CERCS code: T340 Mining