Frontiers in Earth Science (Apr 2022)
Microstructural and Geomechanical Study on Microbial-Carbonized Sand Using Streptomyces Microflavus for Dust Control
Abstract
Microbial carbonization based on carbon-capturing bacteria induced calcium carbonate precipitation has become a new construction material for soil improvement. This paper presents a new technique for dust control in sand using Streptomyces microflavus induced calcium carbonate precipitation. This kind of carbon-capturing bacteria can capture and transform CO2 into carbonate then precipitate calcium carbonate crystals through the microbial carbonization process, which then acts as cementitious materials to bind sand particles. In this way, loose sand particles can be bridged and increase their hardness, consequently forming a consolidated layer for dust control. The Shore hardness of the consolidated layer using Streptomyces microflavus could be improved to 25 HD with a calcium carbonate content of 5.5% after 7 times of carbonization treatment. The microstructure, Shore hardness, and obtained calcium carbonate content were also compared with sand samples treated by Paenibacillus mucilaginosus. These results reveal that the consolidated sand layer using Streptomyces microflavus is sufficient to against wind erosion or rainfall erosion and has better geomechanical performance than Paenibacillus mucilaginosus.
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