Re-evaluation of Lower Palaeozoic limestones from the Prague Basin (Barrandian area, Czech Republic) as a raw material for production of natural hydraulic lime and/or natural cement
Abstrakt
Lower Palaeozoic limestones from the Prague Basin, making up part of the Barrandian area (Bohemian Massif, Czech Republic), have been employed for the firing of construction binders since early Medieval times. Several lithostratigraphic members exhibit variable compositions -from pure limestone to clay/silica-rich members that exhibit a considerable degree of hydraulicity when fired.
Despite extensive explorations for large limestone deposits suitable for various industrial uses in the Prague Basin after WW2, the potential of these rocks for the firing of hydraulic binders, which can be an alternative to Portland cement (hydraulic lime and/or natural cement) remained absolutely unexplored in modern times, despite the fact that multiple sources of evidence of their production and use can be found throughout history. In this study, we have employed several thousand chemical analyses from exploration reports performed since the 1950s, and recalculated them by using traditional indexes used for the evaluation of raw materials suitable for the production of hydraulic lime.
From 12 examined stratigraphic members, 2 have been designated as a raw material eminently suitable for hydraulic lime (or even natural cement); 6 others for moderately hydraulic lime. Based on these results, the most promising sites have been selected as sources of raw materials for experimental firings.