Title: Titania and Silica Nanoparticle-Modified Coatings for Cementitious Materials
Author(s): Qingxu Jin, Marisol Faraldos, Ana Bahamonde, Behnaz H. Zaribaf, and Kimberly E. Kurtis
Publication: Symposium Paper
Appears on pages(s): 97-111
Self-cleaning; Air purification; TiO2; SiO22; NOx; Coating; Photocatalytic cementitious materials
Due to the ubiquity of concrete in the urban environment and the upscaling of nanomaterial production, the incorporation of nanoparticles into cementitious materials has gained increased attention. This study compares the performance of various titania (TiO2) and silica (SiO2) nanoparticles-modified coatings, including their photocatalytic performance and the quality of their adhesion to the cementitious substrates. The photocatalytic performance with respect to air purification and self-cleaning are evaluated by nitrogen oxide (NOx) and methylene blue (MB) dye photodegradation, respectively. The results show that the Portland cement (OPC)-based cementitious materials exhibit greater photocatalytic efficiency than calcium aluminate cement (CAC)-based ones. It is proposed that the superior performance is due to a greater proportion of finer porosity and the presence of high surface area calcium silicate hydrates (C-S-H) in OPC-based cementitious materials. Interactions between coatings and cementitious substrates are examined through wettability and adhesion. The results show that the inclusion of silica layer can affect the interaction of coated cementitious surface with water, as well as the bond strength between coating and cementitious substrate.