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

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

Publication: Materials Journal

Volume:

Issue:

Appears on pages(s):

Keywords: foam–concrete granules; NO_X; porosity, SO_X; TiO₂ nanoparticles

DOI:

Date: 1/16/2023

Abstract:
The atmospheric purification capacity of concrete has not been adequately investigated. This study examines the feasibility of using sustainable foam–concrete granules as a porous material for reducing air pollutants in concrete. To enable the removal of nitrogen oxide (NO_x) and sulfur oxide (SO_x) using titanium dioxide (TiO₂) nanoparticles, foamed concrete was crushed into granules with porosity exceeding 30%. Portland ordinary cement (OPC), fly ash (FA), and ground granulated blast-furnace slag (GGBS) were used as source cementitious materials. OPC was replaced with from 0% to 40% FA and 0% or 40% GGBS by weight. Test results indicate that 30% FA and unit cementitious material 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 SO_x and NO_x 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.