Quando il mosaico incontra la calce. Malte a calce idraulica naturale (NHL) per il restauro musivo

Natural hydraulic limes (NHL) permit restoration mortars compatible with the historical mortars present in the mosaic artefacts both for composition and for physic-mechanical properties. In this paper, after a brief presentation of our studies and applications, carried out over the last fifteen years, of NHL mortars, appropriately formulated to perform precise mosaic restoration tasks, we will move on to a more detailed description of the engineering and application of a new mobile support system for mosaic fragments, previously lifted, entirely made of mortar based on NHL and metakaolin, suitably reinforced and lightened, carried out in collaboration with the Academy of Fine Arts of Naples. It is a system alternative to that of the classic alveolar aluminum panel (more commonly known under the trade name of “Aerolam”), used for relaying mosaic fragments on mobile support. The proposed mortar system is suitable for the required function and competitive in terms of weight with the classic “Aerolam” system; compared to the latter, it allows a reduction in working times and costs, as well as fully satisfies the concept of circular economy (LCA), guaranteeing the recovery of restoration materials at the end of their life.