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Title: The Influence of TiO2 Nanoparticles on the Smart Properties of Alkali-Activated Materials

Author(s): Denny Coffetti, Elena Crotti, Simone Rapelli and Luigi Coppola

Publication: Symposium Paper

Volume: 362

Issue:

Appears on pages(s): 18-37

Keywords: Alkali-activated material; Alternative binders; Self-cleaning; Sustainability; Titanium dioxide

DOI:

Date: 6/5/2024

Abstract:

The purpose of this work is to investigate the influence of the addition of TiO2 nanoparticles on the rheological, physico-mechanical, and photocatalytic properties of alkaliactivated slag-based mortars. The self-cleaning capability of TiO2-containing composites was evaluated by means of accelerated dye degradation tests and 24-month outdoor exposure tests in comparison with Portland-based mortars.

Experimental results show that the variation of the rheological properties of mixtures due to the addition of TiO2 is negligible while there can be a general reduction in the setting times by increasing the amount of the TiO2 content. The use of TiO2 seems to have a minor effect on the elasto-mechanical properties of slag-based mortars at early and long ages. Only alkali-activated materials with low alkali content evidence an increase in compressive strength from 9 to 14% with respect to the same mortars manufactured without nanoparticles.

The beneficial effect of TiO2 addition in self-cleaning capability is evident both in cementitious and alkali-activated mortars under accelerated tests. In particular, regardless of UV light exposure time and dye nature, the color variation increases almost linearly by increasing the nanoparticle content.

Finally, the self-cleaning ability has been evaluated by measuring the color variation during the exposure of mortar samples to the industrial environment for 2 years. Results evidenced the efficiency of titanium dioxide in the reduction of the color variation promoted by the polluted environment.