Experimental techniques for the evaluation of the durability of strengthening works on historical masonry

The restoration of historical buildings is a delicate and complex process in that newly developed strengthening materials, the long-term effects of which have not yet been fully tested, may interact adversely with the materials making up the masonry and their compounds. In the analysis of the behaviour of masonry structures and their constituent materials, increasing importance has been assumed by the study of the long-term evolution of deformation and mechanical characteristics that may be affected by both loading and environmental conditions, especially in the case of structural restoration by means of innovative materials; an issue which is compounded by the problem of the durability of the support-mortar system. The purpose of this investigation is to develop a methodology, mostly of an experimental nature, to be used in laboratory tests as a preliminary design stage for structural interventions, in order to pre-qualify the strengthening mortars and be able to formulate a judgement as to their compatibility and long-term behaviour when applied to historical masonry walls.