Experimental investigation of solidifying desert aeolian sand using microbially induced calcite precipitation

• Published in: Construction & building materials Vol. 172; pp. 251 - 262
• Main Authors: Duo, Li, Kan-liang, Tian, Hui-li, Zhang, Yu-yao, Wu, Kang-yi, Nie, Shi-can, Zhang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 30-05-2018; Elsevier B.V
• Subjects: Analysis; Bio-treatment; Cements (Building materials); Compressive strength; Desert aeolian sand; Mechanical properties; Microbially induced calcite precipitation; Permeability; Solidification; Sporosarcina pasteurii; China; Bio-treatment; Microbially induced calcite precipitation; Desert aeolian sand; Sporosarcina pasteurii; Solidification
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2018.03.255

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•Engineering properties of desert aeolian sand can be improve by MICP technique.•Concentration of solidification solution can affect properties of solidified sand.•The UCS increase and permeability reduction due to CaCO3 content increase.•Calcite crystals cover on the particles surface and fill the pores.
In this study, five different concentrations of solidification solution (0.5, 1.0, 1.5, 2.0 and 2.5 mol/L urea-CaCl2) were used to solidify desert aeolian sand by microbially induced calcite precipitation (MICP). As the concentration of solidification solution increased, the CaCO3 content increased, sand density increased, permeability was reduced and the unconfined compressive strength increased. Formation of CaCO3 was the primary cause of changes in the sand’s properties. Specifically, CaCO3 filled the pores between the sand particles and the pore volume decreased. The CaCO3 formed in response to low concentrations (i.e., 0.5–1.0 mol/L) and high concentrations (i.e., 1.5–2.5 mol/L) of urea-CaCl2 solution played different roles in solidification of the structures.