Physico-chemical material characterization of historic unreinforced masonry buildings: The first step for a suitable intervention

In this paper, a methodology to determine the physico-chemical characteristics of the original mortar used during the construction of the structure was applied as a first step prior to the intervention process. Due to the bad conservation state of the structure, an exhaustive damage analysis was applied to the structure using among others, infrared thermography. Mechanical characterization was also necessary to determine the structural stability of the element and the cohesion and resistance of the original materials. The mortar characterization was carried out using complementary analysis techniques and the conjunction of the results obtained allows the determination of binder type, possible mortar degradations and other characteristics, allowing the selection of the most suitable repair material for the intervention process. The results lead to conclude that we are talking about a lime mortar, discarding the possibility of cement or gypsum as binder material. Particularly, the binder has been characterized as sub-hydraulic or feebly lime, in the middle between pure and hydraulic lime, and it is possible to precise that it was developed using the so called hot lime technology.

► Use of IR thermography as a complementary NDT in structural assessment.
► Establish an evaluation procedure for historical structures.
► Mortar characterization: lime mortar, discarding the possibility of cement or gypsum as binder material.
► Mechanical resistance lower than expected.