G.CARDANI, C.TEDESCHI, L.BINDA and G.BARONIO Dis- Politecnico of Milan

Efflorescence and crypto-efflorescence due to crystallisation of soluble salts in the walls are some of the most frequent causes of damage to facing brick-masonry in the Mediterranean countries. Mortar joints are the most affected in the case of historic masonry. When rain penetration is the only cause of moisture, effective repair can be carried out by re-pointing. Nevertheless, there might be the possibility that non-compatible mortars are chosen and/or that the workmanship is very poor. Under the frame of a work EC Contract (CEE ENV4-CT98-0706), a series of crystallisation tests was carried out, according to RILEM Recommendations, on brick masonry specimens to control the effect of different re-pointing mortars. The long term damage caused by the salts was detected by visual inspection, photographic survey and measured by a laser profilometer. In addition, the bond between the re-pointing and the bricks was also detected by a special application of the bond wrench test.