Results and Conclusions of Laboratory Characteristics of Soft Limestone from Central Poland as a Construction Material

摘要

The paper presents the physical and mechanical characteristics of a Cretaceous soft limestone from Poland.For several decades,since the end of the 19th century,this stone had been widespread as a common building material in Kolo Basin(Kotlina Kolska)-a lowland region in the central part of the country”.The popularity of this material in the mentioned period resulted in the emergence of a unique architecture in the region's landscape.Despite the decline of its use,as it was replaced by more modern construction materials,over 2000 of these traditional structures exist to this day.The recent years have seen the rising of a vivid discussion over the cultural value they might represent.Likewise debated have been the efforts aimed at the protection and restoration of these structures,as they can be seen as an important element of the region's cultural heritage.Particularly,it is put under consideration to bring the local limestone once again into popular use,as a trend to return to the use of traditional,natural construction materials develops.In the present situation,the including the soft limestone into the mentioned trend as a raw material or a product would require taking certain steps in its marketing as a viable option for modern use.For this reason,an analysis of its functional characteristics in relation to the modern technical standards would serve as a solid support to the already proven durability of the structures erected decades ago,during the high period of its popularity.A series of tests was conducted,obtaining a petrographic description and determining its mineralogical composition.Furthermore,measures were made of its physical and mechanical properties i.e.bulk density,open porosity,water absorption at atmospheric pressure,frost resistance and compression strength.These tests were based primarily on the methodology recommended by the harmonized EU standards and exceptionally some of the older national standards.The parameters obtained during the laboratory,with the frost resistance in particular,appear not entirely satisfactory.However,the good condition of numerous structures erected using the examined material decades ago indicate that,amongst other conclusions,choosing a proper construction technique,one mastered by practical experience,results in providing these traditional construction materials durability superior to the one determined by laboratory examination.