Sound-insulation and photocatalytic foamed concrete prepared with dredged sediment

Abstract

Recycling of dredged sediment (DS), derived from the routine dredging operation of rivers, lakes and seas, into construction materials represents an eco-friendly way to alleviate the burden on the environment. At higher incorporation dosages, however, DS causes a dramatic reduction in the mechanical properties of the host materials, which greatly stymies a broader application. In this study, DS from Taihu Lake, combined with ground granulated blast-furnace slag (GGBS) and calcium carbide slag (CCS), was used to produce low-strength foamed concrete (FC). Moreover, visible-light active Bi4Ti3O12 photocatalyst was added to the developed FC to obtain photocatalytic-functional and sound-proof products, which can be used as highway barrier walls. The results showed that within a dry density range of 500–1000 kg/m3, the compressive strength of the FC decreased greatly with an increase in the porosity. However, above 1000 kg/m3, the porosity exerted a much dwindled impact on the compressive strength. The pore structure of the sediment-based FC played a decisive role in influencing the basic properties and functional performance, which might follow the fractal characteristics. At a fixed dosage of foaming agent (hydrogen peroxide (HP)), the specimens prepared with 60% cement and 40% DS (DS-40) had the best sound insulation effect (1767 m/s, 9% HP), the lowest thermal conductivity (0.2831 W/m·k, 6% HP) and an excellent photocatalytic NO removal (14.1%, Bi4Ti3O12), which was the optimal mixture for manufacturing sound barrier walls. A broader application of photocatalytic-functional sediment-based FC offers a sustainable way in recycling DS, reducing air pollution and creating pleasant living environments.