Microstructural and physical-mechanical analysis of the performance of nanostructured and other compatible consolidation products for historical renders

Abstract

This work is inserted in a wider project aiming at the conservation and durability of historical renders, through compatible techniques and materials; in particular the restitution of cohesion of historical renders is studied. Surface consolidation, directed to restore cohesion and stability, is based on the use of materials with aggregating properties. This operation is reached usually through the use of inorganic or mineral consolidants, which are preferred to organic ones, due to better compatibility and durability. Based on the results of previous studies, two mineral compatible products were selected: a commercial dispersion of nanoparticles of calcium hydroxide in propanol and a calcium-silicate product, consisting on a limewater dispersion of ethyl silicate. Consolidation products were applied on mortar specimens (mortar prisms and mortars applied on bricks) in order to assess their efficacy by determining their microstructural and physical-mechanical properties, before and after consolidation treatment. A low binder ratio mortar was studied with both consolidants. Microstructural (optical and SEM microscopy) and chemical analysis of the consolidation products and of the consolidated samples were performed; physical-mechanical analysis, namely superficial hardness is reported.