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<p>Microbially induced carbonate precipitation (MICP) is a promising ground improvement technique which has recently gained significant research attention. The magnesium-mediated bio-cementation has been proven to improve the physical and mechanical properties of cemented sand, while little focus has been pay for its underlying mechanism. This study systematically investigates the effects of different magnesium sources and magnesium-to-calcium (Mg/Ca) ratios on the MICP treatment. MICP experiments with different cementation solutions are conducted to reveal the effects of magnesium on carbonate precipitation efficiency, mineral composition, and the mechanical and hydraulic properties of bio-cemented sands. The strength and permeability of the bio-cemented sand are then assessed through UCS and variable-head permeability tests. The results show that magnesium ions not only alter the types and proportions of carbonate crystal forms, but also modify their precipitation patterns within the sand matrix, consequently influencing the macroscopic mechanical and permeability characteristics of bio-cemented sands. The synergistic application of insoluble magnesium sources with soluble calcium sources in MICP process effectively reduces retarding effects of high ion concentration on bacterial urease activity. This optimized approach significantly enhances the macroscopic mechanical performance of bio-cemented soils while maintaining favorable cementation uniformity.</p>

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Mechanism of magnesium-enhanced bio-cementation in improving physical and mechanical properties of cemented sands

  • 期刊论文

  • 发表日期：

    2026年3月30日

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  • Chaoxian Wang,
  • Ming Huang,
  • Jim S. Shiau,
  • Mingjuan Cui,
  • Meiling Chen

摘要

Microbially induced carbonate precipitation (MICP) is a promising ground improvement technique which has recently gained significant research attention. The magnesium-mediated bio-cementation has been proven to improve the physical and mechanical properties of cemented sand, while little focus has been pay for its underlying mechanism. This study systematically investigates the effects of different magnesium sources and magnesium-to-calcium (Mg/Ca) ratios on the MICP treatment. MICP experiments with different cementation solutions are conducted to reveal the effects of magnesium on carbonate precipitation efficiency, mineral composition, and the mechanical and hydraulic properties of bio-cemented sands. The strength and permeability of the bio-cemented sand are then assessed through UCS and variable-head permeability tests. The results show that magnesium ions not only alter the types and proportions of carbonate crystal forms, but also modify their precipitation patterns within the sand matrix, consequently influencing the macroscopic mechanical and permeability characteristics of bio-cemented sands. The synergistic application of insoluble magnesium sources with soluble calcium sources in MICP process effectively reduces retarding effects of high ion concentration on bacterial urease activity. This optimized approach significantly enhances the macroscopic mechanical performance of bio-cemented soils while maintaining favorable cementation uniformity.