Combined Effect of Photocatalyst, Superplasticizer, and Glass Fiber on the Photocatalytic Activity and Technical Parameters of Gypsum

In this study, gypsum plasters enriched with the modified photocatalyst TiO2/N and additive components were prepared and analyzed in detail. The aim of this work was to recognize the combined impact of a photocatalyst, polycarboxylic superplasticizer (SP), and glass fiber (F) on the properties of the composed building materials. The mutual compatibility was verified in relation to self-cleaning and air-purifying activity as well as to the technical parameters defined in standards for gypsum materials. The measurements revealed that photocatalytic gypsum material can have high mechanical strength and limited shrinkage as a result of superplasticizer contribution in form of a water-reducing and well-dispersive agent. Normal consistency was achieved by the addition of 0.01 wt % of SP to photocatalytic gypsum mortar or by the addition of 0.2 wt % of SP with a 12% reduction of water. This study also explains why glass fiber fulfills the role of inner reinforcement only if a superplasticizer is simultaneously added to the gypsum matrix. It is possible, by the combined effect of TiO2/N, a polycarboxylic superplasticizer, and glass fiber, to achieve NOx degradation at a high level. Moreover, the significantly improved self-cleaning properties of the complex gypsum plasters surfaces from dye pollutants in comparison to a gypsum plaster with solely a TiO2/N photocatalyst indicate the synergistic effect of the three considered additives.