Metakaolinite/TiO2 composite: Photoactive admixture for building materials based on Portland cement binder

Novel latent hydraulic and photoactive admixture metakaolinite/TiO2 was prepared, characterized and evaluated as a partial replacement for the Portland cement in mortars. The main component of this novel composite material is metakaolinite containing the anatase nanoparticles anchored on its surface. The values of the compression strength measured for the mortars containing metakaolinite/TiO2 composites reached higher values in comparison to the mortar without this admixture. Photodegradation activity of the mortars with given amount of the metakaolinite/TiO2 admixture against nitric oxide (NO) was tested using the modified ISO standard. The results showed that the conversion of NO increases with the increasing content of TiO2. The synergistic effect of the photodegradation activity and the latent hydraulicity in this material can be utilized in building industry to decrease concentration of selected air pollutants e.g. in areas affected by traffic pollution.