On site composites-to-masonry bond evaluation in presence of rising damp and salt crystallization

A research has started aiming at evaluating the influence of aggressive environmental conditions (moisture, temperature and soluble salts presence) on the bond between various composites and masonry substrates already decayed. A series of on-site experimental tests was carried out on full-scale masonry models, built in open air in a polluted area and artificially exposed since years to capillary rise of a solution of water and salt, so to create salt crystallization cycles. The models are one-floor constructions built in either sandstone or softmud-brick masonry, representing a simple historic masonry structure. Composite strips were applied to the two masonry substrates in order to evaluate the bond at three levels, characterized by different conditions (wet, dry, alternate wet/dry) and crystallization exposure. The first results of the pull-off tests carried out after three months from composite application, are here discussed.