H. Paiva

Characterization of Renders, Joint Mortars, and Adobes from Traditional Constructions in Aveiro (Portugal)

The huge and special architectural heritage of Aveiro (Portugal) from the beginning of the past century is characterized by the use of stone or adobe (mud sun-dried blocks), as structural material, with lime renders and mortars. Some of those buildings are situated in the city core and show different degradation degrees, promoted either by weathering in urban context, lack of maintenance, or the seaside proximity. To preserve this type of construction, a study was carried out in order to characterize renders, joint mortars and adobes, to know the composition and behaviour of each in the construction. For this purpose, samples were extracted from various locations of several buildings. The study of mineralogy was performed by x-ray diffraction (XRD), their thermal behaviour was obtained by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and these data were complemented by chemical analysis by x-ray fluorescence spectroscopy (XRF). The aggregate particle size distributions were obtained by dry sieving. Mechanical compressive strength (Rc) and capillarity performance were also evaluated. The results have shown that the mineralogical composition of joint mortars, renders and adobes are similar and the presence of efflorescences was detected in some samples. In general the capillary coefficients of the adobe samples are higher than those of the renders and mortars related with them. The Rc values were similar for the renders, mortars, and adobes. These studies have also been undertaken to support sustainable interventions, allowing the extraction of salts, the consolidation of renders and production of new compatible renders and mortars to substitute and refill the gaps capable of guaranteeing the integrity and prolonging the existence of this kind of architecture and building technique.