Preliminary results on the characterization of limestone from Cais das Colunas (Lisbon, Portugal)

Abstract

The historic quay Cais das Colunas was constructed during the decades 1770-1790. In 1996 was partially dismounted and in 2008 was reconstructed. During these interventions some samples of materials were collected, in order to characterize them. It is common sense that the (re)construction of Lisbon after the earthquake recurred, almost strictly, to Portuguese lioz limestone from Pero Pinheiro region. Recent historic survey revealed that other regions of Portugal, such as Paço de Arcos and Carcavelos, supplied stone material to the great building yard that was Lisbon since 1758 to the end of that century. It was possible to collect and study samples from three distinct stone blocks: a fragment of a substituted stone block of the pavement (ST1); a fragment from the basis of east column (ST2); and a block of the quay's core (ST3). All of these were discarded in the reconstruction intervention of 2008, so the harm of these studies to the monumental quay is null. The present study focuses on the determination of (1) water absorption by capillarity and (2) uniaxial compressive strength. The tests were developed in order to preliminary characterize the stone material used in the construction of the monumental quay. It were followed the European Standards EN 15801:2009 and EN 1926:2006. Samples ST1 and ST3 showed a similar behavior in capillarity water absorption with high values 0,738 g/mm2 and 0,597 g/mm2 curve than ST2 which present low capillarity water absorption with an average of 0,113 g/mm2. Also, as expected by the capillarity values, the ST2 samples present the highest value (87,77 MPa). ST1 and ST2 show 72,02 MPa and 78,38 MPa, respectively. It is possible a preliminary identification of different types of lioz limestone. Samples ST1 and ST3 demonstrated similarities on the studied parameters, comparing to the ones of ST2 – that revealed lower water absorption and higher compressive strength. Further studies, in order to the mineralogical and chemical characterization of the specimens, are being carried out. The identification of the quarries is also a goal of the research project.