Title: Development of Foam-Concrete Granules Coated with TiO2 Nanoparticles

Author(s): Keun-Hyeok Yang, Ju-Hyun Mun, Seung-Jun Kwon, and Jong-Won Kim

Publication: Materials Journal

Volume: 120

Issue: 3

Appears on pages(s): 3-18

Keywords: foam-concrete granules; nitrogen oxide (NOx); porosity; sulfur oxide (SOx); titanium dioxide (TiO2) nanoparticles

DOI: 10.14359/51738507

Date: 5/1/2023

Abstract:
The atmospheric purification capacity of concrete has not beenadequately investigated. This study examines the feasibility ofusing sustainable foam-concrete granules as a porous materialfor reducing air pollutants in concrete. To enable the removal of nitrogen oxide (NOx) and sulfur oxide (SOx) using titanium dioxide (TiO2) nanoparticles, foam concrete was crushed into granules with porosity exceeding 30%. Ordinary portland cement (OPC), fly ash (FA), and slag cement were used as source cementitious materials. OPC was replaced with 0 to 40% FA and 0 or 40% slag cement by weight. Test results indicate that 30% FA and unit cementitious materials content exceeding 500 kg/m3 (31.2 lb/ft3) are optimal for replacing cement and foam-concrete granules, respectively. Considering the particle-size distribution and specific surface area, 6 to 13 mm (0.24 to 0.51 in.) and 6 to 9 mm (0.24 to 0.35 in.), were selected as optimal granule sizes. The coating procedures yielded improved SOx and NOx removal, with the removal rates reaching 83.8 and 45% using granules of 6 to 9 mm (0.24 to 0.35 in.), respectively. Consequently, the foam-concrete granules coated with TiO2 nanoparticles are promising in developing porous concrete with the reduction capability of air pollutants.