Daniele Enea

Photocatalytic Properties of Cement-Based Plasters and Paints Containing Mineral Pigments

Innovative cement-based premix products for surface coating of buildings that possess photocatalytic activity arouse great interest because of the results they can achieve in reducting air pollution and maintaining aesthetics. This photoactivity is induced by a photocatalyst, titanium dioxide, that can accelerate the oxidation processes of air pollutants, particularly nitrogen oxides and volatile organic compounds, which are mainly produced by incomplete combustion of fuel and are present in urban environments through the exhaust gases of motor vehicles. Surfaces that are coated with these products acquire a self-cleaning characteristic (maintenance of original color) because the decomposition of organic compounds significantly reduces the ability of atmospheric particles to adhere to treated surfaces, thus facilitating their removal and ensuring a more durable color. These products are particularly suited for use in highly congested areas (i.e., historical centers of cities, tunnels, roads), where air pollution reaches significant levels. This study describes the photocatalytic performances of a series of premix products containing mineral pigments. The tested products are based on hydraulic binders (natural hydraulic lime and cement), and the pigments are inorganic. A wide range of colors was chosen, and the performances of base products were investigated to provide a wider choice to the designers. After a brief introduction of the principles of photocatalysis, the results of a wide experimental work are described. Some consideration of methods of curing and natural exposure is also reported.

Service Life of Cementitious Photocatalytic Paints Newly Formulated

The use of photocatalytic products for surface coating of buildings contributes to the sustainability of building interventions, due to the reduction of some atmospheric pollutants and self-cleaning attitude. The world market produces a wide range of coatings, applied in limited thickness, transparent and opaque, high initial performance, although data on their durability are still missing. The knowledge of the performance over time of such innovative products is necessary according to the new EU Regulation No. 305/2011, which introduced for construction works, the seventh requirement on their sustainability and particularly their durability. The study concerns the evaluation of the durability of white photocatalytic paint, TX Active® cement-based. The methodology is based on ISO 15686 and consists in monitoring the most significant selected parameters, during laboratory accelerated aging tests and natural environment exposure. Measured performance were the morphological appearance of the surface, the photocatalytic activity and the color. The results obtained demonstrate the efficiency in time and the maintenance of performance of the photocatalytic paint, above limits defined by standards and conservation of color.

Innovative Siloxane Coating Formulations: The Experimental Assessment of the Durability of Colour

Maintenance programming of civil and industrial buildings is a relevant problem, especially in a global situation where natural resources are increasingly limited. Accurately knowing the durability of building products and components, essential for a sustainable use of resources, becomes more and more important after the recent 18 January 2011 resolution of the European Parliament, which introduced the seventh requirement on construction products, specifically regarding the sustainability and therefore the durability of such. This study concerns the evaluation of the durability of some innovative coatings based on acrylic-siloxane resins containing several pigments, used for building external decorative finishing, applied in thin thickness and of different basic components. The parameters investigated are: the surface appearance and the maintenance of the original colour, significant for the aesthetic quality of the architecture. The paper presents the first results of the experimental study on coating materials, produced by Hydrate Ltd, performed according to ISO 15686, aimed at defining the Reference Service Life, by monitoring the behaviour over time of artificially aged samples in the climatic chamber and external exposed samples, as well as the monitoring of a case study.