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Effect of activated carbon on microbial-induced calcium carbonate precipitation of sand

Zhao, Yang, Fan, Cunbin, Liu, Pinghui, Fang, Houguo, Huang, Zhiquan
Environmental earth sciences 2018 v.77 no.17 pp. 615
activated carbon, bacteria, calcium carbonate, chemical precipitation, compression strength, crystals, mechanical properties, microstructure, sand, soil, China
Microbial-induced calcium carbonate precipitation (MICP) is a sustainable technique to transform or improve physical and mechanical properties of soils. This paper aims to study the effect of activated carbon (AC) on the property of bio-treated China Standard sand. Six sample groups were prepared considering various dosages of cementation solutions and bacterial suspensions. In each group, samples were prepared at six different AC ratios (0%, 0.2%, 0.5%, 1%, 2%, and 3% by weight of sand). Bacterial retention ability, calcium carbonate mass, unconfined compression strength (UCS), and microstructures of bio-treated samples were examined and evaluated in the presence of AC. It was found that the improved yield of calcium carbonate crystals and increased UCS were correlated to the enhanced bacterial retention ability attributed to AC. In addition, the test results showed that the amount of cementation solution played an important role in the MICP process, but volume variation of the bacterial suspension had a little effect on the bio-treated samples.