WHITE CEMENT FOR ARCHITECTURAL CONCRETE, POSSESSING PHOTOCATALYTIC PROPERTIES

White cement is a key ingredient in architectural and decorative concrete. By using it, in particular, the resulting concrete not only becomes an expressive material that having an infinite range of colour tones, intensifies one of its aesthetic qualities, but could also gain remarkable validity in terms of structural qualities due to its high mechanical strength. This paper is intended to provide technical information to both designers, architects and contractors, in order to obtain a high performance concrete, similar to the natural materials like marble, possessing relevant properties in terms of durability, performances and added environmental properties. Indeed, a new type of white cement is here proposed, containing TiO2, possessing photocatalytic properties which allow to maintain the aesthetic characteristics of concrete over time and contribute to eliminate dangerous pollutants from the urban environment. A remarkable application is also described, concerning the innovative construction of a church in Rome, named “Dives in Misericordia” whose sails were built using white High Performance Concrete, based on this new cement. Main physical and mechanical properties of this HPC are described. 1.0 WHITE CEMENT Thanks to the continuous laboratory research efforts aimed to obtain outstanding properties besides the excellent degree of whiteness, white cement has been rendered increasingly and noticeably a high performance binder. White clinker is produced by taking care that the content of ferrous composites and other heavy metal composites does not exceed 0.15%, whose presence give common Portland cement its distinctive grey colour. To this purpose, it is first of all necessary to carefully select the raw materials: only mineralogically pure kaolins and white limestones are used.