Biocementation of Martian Regolith Simulant with In Situ Resources

Biocementation is expected to be an energy efficient and environmentally benign alternative method for the production of cement products, and it has been extensively studied on Earth. This research is focused on developing bioprocesses to produce bioconcrete columns using Mars-compatible microalgae and simulated Martian regolith. A marine microalga, Thraustochytrium striatum was tested to make Martian regolith-based columns in the presence of CaCl2/urea. Three different biogrouting methods were investigated including simultaneous, sequential, and batch circulation of microalga cell biomass and CaCl2/urea in the columns. The need of postbiogrouting column soaking was also studied. The columns were characterized by the unconfined compressional strength (UCS), CaCO3 formation by X-ray diffraction (XRD), and microstructure by scanning electron microscope. T. striatum is capable of biocementation and can produce urease to produce CaCO3 precipitation for regolith columns. Overall, the sequential biogrouting is better than the simultaneous counterpart. The best UCS value found for the columns reached 523 kPa. Batch biogrouting has potential to achieve high UCS, but fast CaCO3 clogging needs to be overcome in the future research. The column soaking is not needed because it worsened the UCS.