Comparative evaluation of freeze and thaw effect on strength of BEICP-stabilized silty sands and cement- and fly ash-stabilized soils

• Published in: Acta geotechnica 2023-02, Vol.18 (2), p.1073-1092
• Main Authors: Hoang, Tung, Do, Huyen, Alleman, James, Cetin, Bora, Dayioglu, Asli Y.
• Format: Article
• Language: English
• Subjects: Calcium; Calcium carbonate; Calcium carbonates; Calcium chloride; Calcium permeability; Carbonates; Cement; Chemical precipitation; Columns (structural); Complex Fluids and Microfluidics; Compressive strength; Concrete; Cycles; Durability; Engineering; Enzymes; Evaluation; Fly ash; Foundations; Geoengineering; Geotechnical Engineering & Applied Earth Sciences; Hydraulics; Microcracks; Microorganisms; Microstructure; Moisture content; Moisture effects; Permeability; Plants; Porosity; Portland cement; Portland cements; Research Paper; Sandy soils; Soft and Granular Matter; Soil; Soil columns; Soil microorganisms; Soil moisture; Soil permeability; Soil porosity; Soil properties; Soil resistance; Soil Science & Conservation; Soil stabilization; Soil strength; Soil treatment; Solid Mechanics; Toughness; Urea; Urease
• ISSN: 1861-1125; 1861-1133
• DOI: 10.1007/s11440-022-01612-7

This paper addresses a soil bio-stabilization technique using bacterial enzyme-induced calcium carbonate precipitation (BEICP) as an alternative to previous conventional methods including microbial-induced carbonate precipitation and plant-derived enzyme-induced carbonate precipitation. The extracted urease enzyme of viable S. pasteurii was used as a biological source along with calcium chloride and urea to solidify sandy soil and silty sand soil. The bio-treated soil columns were subjected to freeze and thaw ( F – T ) cycling for a durability evaluation. Engineering properties of bio-cemented soil including unconfined compressive strength, calcium carbonate contents, moisture contents, porosity, permeability, and microstructure were examined before and after the F – T durations. It was found that although bio-stabilizer was able to increase a frost duration of soil, the F – T cycling significantly impacted on the compressive strength of bio-treated soil, due to a formation of microcracks. This investigation has revealed that the BEICP method provided a similar capacity in F – T resistance of soil as using the traditional Portland cement stabilizer, whereas the class F fly ash did not improve F – T durability of medium dense soil.