Rubble Stone Masonry Walls in Portugal: Material Properties, Carbonation Depth and Mechanical Characterization

A significant proportion of Portuguese ancient buildings have structural masonry walls. Therefore, it is important to study this building typology in order to define appropriate structural rehabilitation interventions, whenever necessary. This article presents the results of research carried out at Universidade NOVA de Lisboa on the material properties, of rubble stone masonry walls, including the evolution of carbonation depth over time and mechanical characterisation under compression and shear load tests. It was found that the mechanical behavior of the unreinforced masonry specimens is mostly influenced by the reduced compression and tensile strength of the air-lime mortar. A formulation to estimate the carbonation depth and the masonry compressive strength as a function of time is proposed and the Strut-and-Tie Method is used to estimate the resistance of specimens under compression and shear forces. The results of this study are part of a major research project studying the mechanical behavior of unreinforced rubble stone masonry walls (unreinforced masonry—URM), evaluating different strengthening solutions for ancient rubble stone masonry walls (Pinho 2007; Pinho et al. 2012a, 2014a, 2014b) and characterizing the building materials used in both URM and strengthened walls.