Exposed Aggregate Areas and Photocatalytic Efficiency of Photocatalytic Aggregate Mortar

L. Zheng (Corresponding Author), M. R. Jones, L. Yang, A. Hakki, D. E. MacPhee

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Abstract

Having the potential to remove NOx air pollutants, generated by vehicles and other anthropogenic combustion processes particularly in urban areas, photocatalytic concrete has attracted significant commercial interests all over the world. In contrast to typical photocatalyst applications in concrete, in which TiO2, the most utilised photocatalyst, is dispersed within the cementitious materials, the study reported here utilises TiO2-coated aggregates. Used in an exposed aggregate finish, this format aims to have a higher photocatalytic efficiency than TiO2 – cement bound materials. An exposed TiO2-coated aggregate has the potential to provide a significant higher proportion of catalyst to direct UV radiation and to minimise performance lost due to occlusion. The surface area on the aggregate exposed on the test mortar samples was measured with 3D imaging techniques. Thereafter, photocatalytic efficiency was measured in comparison with that of the TiO2 cement mortar. The relationship between exposed area for photocatalytic reaction and photocatalytic efficiency was established. This indicated that the photonic efficiency increases with increasing exposed area, regardless of the method to support the catalyst, i.e. either within the cement paste or externally mounted on the aggregate. The data confirm that exposing coated aggregate significantly enhances photonic efficiency.
Original languageEnglish
JournalMagazine of Concrete Research
Early online date22 Feb 2019
DOIs
Publication statusE-pub ahead of print - 22 Feb 2019

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Keywords

  • aggregates
  • mortar
  • testing
  • apparatus & methods
  • TiO2 coated
  • exposed surface area
  • photocatalytic efficiency

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