Cementitious materials containing nano-carriers and silica for the restoration of damaged concrete-based monuments

The conservation of damaged concrete-based monuments is a demanding challenge for the contemporary world of cultural heritage, given the great 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 types of damages that affect these structures, i.e. delamination problems and cracks of different size. Formulations were improved with various additives, in order to obtain an easy application, a good workability of the paste and a proper setting time, according to the specific application. Silica was included in the formulations to enhance the adhesion to old concrete substrates, whereas 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, which allowed us to get a complete overview of the physico–chemical features of these repair 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 obtained, the formulations were applied at the War Memorial of Torricella Peligna (Italy), confirming their great potentialities in the field of historic concrete-based monuments conservation.