A PROBABILISTIC APPROACH TO INVESTIGATE THE PHYSICAL COMPATIBILITY BETWEEN BEDDING AND RE-POINTING MORTARS

The decay due to salts can seriously compromise the conservation of the exposed surface of the cultural heritage. This attack, at first, compromises the mortar joints. When choosing a mortar for re-pointing the existing masonry, an on-site survey must be carried out on the causes of the damage and their effects on the masonry, and perform laboratory characterization tests of the most representative materials (mortars, bricks, stones ) present in the masonry. At the end of the investigation the results could help in the choice of the most appropriate intervention and of the materials for re-pointing. The research has pointed out the great importance of the compositional and microstructural features of porous material on their salt-decay attitude and the need for experimental work taking into account the masonry substrate. Salt-decay attitude is investigated through laboratory salt crystallization and porosimetry tests. The damage parameter assumed are: the loss of material from the surface measured through a laser profilometer device, and the pore distribution obtained by MIP test. The aim of this research is to correlate the damage and its evolution with the different size and distribution of the pores into the repointing mortars. This correlation will be investigated using a probabilistic approach.