The Durability Experimental Evaluation of Photocatalytic Cement-Based Materials Bruno Daniotti 1 Sonia Lupica Spagnolo 2 Rosanna Galliano 3 ABSTRACT Photocatalytic cement-based materials for building applications represent one of the most interesting developments in the construction field in the last few years. In order to study their performances at international level, they have already been object of many research programmes: their application, in fact, allows to obtain performances such as the removal of some air pollutants, the dirtiness prevention or the anti-bacteria and deodorization actions. Thanks to their capability to exploit luminous energy (solar or artificial) for activating chemical reactions of oxidation, which can neutralize the adsorbed pollutants. As for every innovative material, besides the study of their initial performances, it is necessary to know their behaviour in the long run and to define their Service Life: with this aim, an experimental programme for monitoring the photocatalytic activity over time for such materials was undertaken at Politecnico di Milano. The idea is to use a photocatalytic plaster for the refurbishment of “Torre Velasca”. For that, several experiments were commissioned to the laboratory of “Durability Building Components” of BEST since April 2010. These experiments are aimed to study accelerated ageing of representative samples of new rendering, in order to evaluate durability as integrity, colorimetric variations and photocatalytic performance over time. The paper describes the designed experimental methodology and the main results after accelerated ageing tests. KEYWORDS Photocatalytic, Experimental evaluation, Accelerated ageing, Torre Velasca. 1 Politecnico di Milano, BEST Department, Milan, ITALY, 20133, piazza Leonardo Da Vinci 32, Phone +39 0223996002, Fax +39 0223996020, bruno.daniotti@polimi.it 2 Politecnico di Milano, BEST Department, Milan, ITALY, 20133, piazza Leonardo Da Vinci 32, Phone +39 0223996052, sonia.lupica@polimi.it 3 Politecnico di Milano, Milan, ITALY, 20133, piazza Leonardo Da Vinci 32, rosanna.galliano@mail.polimi.it