Cementitious Materials Containing Nano-Carriers and Silica for the Restoration of Damaged Monuments

The restoration of damaged concrete-based monuments is an open challenge for the contemporary world of cultural heritage, given the number of historic concrete-based monuments built in the last century that are prone to continuous damages. In this work, we developed three different cement-based formulations to address the repair of diverse type of damages that affect these structures, i.e. delamination problems and cracks. Formulations were improved with various additives, so to obtain an easy application, a good workability of the paste and a proper setting time, depending on the specific application. Silica was included in the formulations to enhance the adhesion to old concrete substrates, while halloysite nanotubes loaded with a corrosion inhibitor were also incorporated in the repair materials, to address in an innovative way the problem of corrosion of steel rebars. The formulations were characterized with a multi-technique approach, in order to obtain a complete overview of the physico-chemical features of the materials. In addition, the adhesion of the formulations to old concrete substrates was investigated, as well as the release of the corrosion inhibitor within the cement matrix. Given the promising results, the formulations were applied by an expert restorer at the War Memorial of Torricella Peligna (Italy), confirming their great potentialities in the field of historic concrete-based monuments restoration.