Utilization of Photoactive Kaolinite/TiO₂ Composite in Cement-Based Building Materials

Abstract

Titanium dioxide (TiO₂) is the most studied photocatalyst with application potential in many branches of industry. Building industry represent the sector, where the photoactive TiO₂ have been already successfully utilized. Concretes, plasters, paints are building materials where the photoactive TiO₂ is widely tested. However the amount of TiO₂ in these materials is limited with respect to their final properties. If the TiO₂ replaces the certain amount of cement in concretes, the resulting compressive strength decreases when this photocatalyst is added in non-adequate content. The surface of kaolinite particles can serve as a matrix for nanosized TiO₂ growing what results in photoactive composite – kaolin/TiO₂ formation. After the calcination of this composite the process of kaolinite dehydroxylation is responsible for metakaolinite formation and composite metakaolinite/TiO₂ with latently hydraulic properties originates. If the metakoline/TiO₂ is used for partial cement replacement the compressive strength of resulting samples is notably increased and its surface shows photodegradation ability against rhodamine B.