Mariateresa Lettieri

Durability Issues and Challenges for Material Advancements in FRP Employed in the Construction Industry

The use of fiber reinforced polymer (FRP) composites for the rehabilitation of buildings or other infrastructure is increasingly becoming an effective and popular solution, being able to overcome some of the drawbacks experienced with traditional interventions and/or traditional materials. The knowledge of long-term performance and of durability behavior of FRP, in terms of their degradation/aging causes and mechanisms taking place in common as well as in harsh environmental conditions, still represents a critical issue for a safe and advantageous implementation of such advanced materials. The research of new and better performing materials in such fields is somewhat limited by practical and economical constrains and, as a matter of fact, is confined to an academic argument.

Non-destructive and laboratory diagnostic study on the mosaic of the crypt of St. Nicholas (Bari, Italy)

The crypt of St. Nicholas in Bari, Southern Italy, is a building of cultural worldwide importance. Inside the crypt a mosaic develops on the apsidal floor and along a parietal seat placed along the apsidal masonry, in the form of cladding. A surviving portion of the mosaic pavement is also preserved in the right lateral chapel. Integrated non-destructive survey and laboratory analyses were undertaken for the diagnostic study of the mosaic. GPR prospection was successfully applied to the study of its conservation state, that is strictly related to the condition of the subsoil, in particular to the presence and distribution of water. The presence of water, whose rise interests also some portions of the masonry and water content distribution were identified by the results of electromagnetic wave velocity analysis in GPR data. The decay visible on the tesserae evidenced widespread spalling and crumbling as typical forms that selectively affect the different materials of the tesserae of the mosaic. Samples taken from them were investigated by optical microscopy, X-ray diffraction, ion chromatography, infrared spectroscopy and thermogravimetric analyses, in order to identify the constituent materials and the products of their decay. The application of the integrated methodologies showed its effectiveness in order to acquire a quite complete knowledge for diagnostic purpose. Decay appeared to be due to the combined presence of water and soluble salts and it has different effects depending on the materials characteristics.

Mortars with Phase Change Materials (PCM) and Stone Waste to Improve Energy Efficiency in Buildings

The main objective of this contribution is the study of mortars with the incorporation of polymer-based phase change materials (PCM) for the improvement of energy efficiency in buildings. The mortars are intended for an indoor thermal comfort in the typical climatic conditions of the Southern European countries. Production waste, such as stone powder from quarry, will also be incorporated in the mortars. The finer powder is proposed as mortar aggregate and, at the same time, as support for the PCM. Firstly, different procedures aimed at effectively introducing the selected polymeric material (PEG) into the Lecce Stone have been performed. The chemical and thermal characterization of these compounds has been carried out. The LS/PEG composites have been, then, added to a mortar. Experiments are in progress in order to characterize from chemical, physical, and thermal point of view the mortars with and without PCM, following the recommendations of the international standards in this field. In addition, the studied materials will be used to build laboratory-scale prototypes that will be tested in real environmental conditions.