Bio-carbonization of Reactive Magnesia for Sandy Soil Solidification

Abstract

Bio-carbonization of reactive magnesia (r-MgO) is a new technology for sandy soil solidification. In this study, two sets of tests were conducted to investigate the influence of r-MgO contents on the bio-solidification effects of sandy soils, with the analysis of the unconfined compressive strength (UCS), permeability coefficient, sonic time value, and precipitation content. The relationship between r-MgO contents and solidification effects with a single treatment cycle was studied in the first sand solidification test. Then, the second sand solidification test was further conducted until their permeability coefficient reached about 10⁻⁶cm/s to determine the maximum treatment cycle under various r-MgO contents. The results showed that the UCS, permeation resistance, and carbonate precipitation content were positively related to the r-MgO content if the solidification treatment was applied only once, while the sonic time value showed an opposite trend. Moreover, the maximum treatment cycle obtained under various r-MgO contents varied greatly. A high dosage of r-MgO could clearly reduce the maximum number of treatment cycles of the sand column, especially the r-MgO content larger than 15%. Decreased treatment cycle reduced carbonate precipitations in the sand column and decreased the UCS by over 40%. There was a close relationship between UCS and average carbonate precipitation contents for the bio-carbonated sand columns with the only one treatment cycles. However, the UCS of sand columns with multiple treatment cycles varied greatly within a similar average precipitation content. The results of this study lay a solid foundation for applying bio-carbonization of r-MgO in sandy soil solidification.

Keywords:

• Bio-carbonization
• reactive magnesia
• r-MgO content
• maximum treatment cycle

Authors’ contributions

Jiancai Yan and Huaxun Wu designed the study and performed the laboratory experiments. Jiancai Yan and Yamin Ding analyzed the data. Jiancai Yan wrote the paper with input from all of the authors. Huaxun Wu, Yamin Ding, and Jiahua Fan reviewed and revised the paper. All of the authors read and approved the final manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Some or all data, models, or codes that support the findings of this study are available from the corresponding author upon reasonable request.