High strength bio-concrete for the production of building components

Bio-concrete produced via microbially-induced calcium carbonate precipitation (MICP) is a potentially CO2-neutral alternative to Portland-cement-based concrete because biomineralization emits no process-related CO2 and stores CO2 as carbonate. Achieving high compressive strength with sufficient component depth has been a key challenge. This study combines: (i) urease-active calcium carbonate powder (UACP) instead of free bacterial cells, (ii) optimization of aggregate packing density, and (iii) an automated stop-flow pressure injection method. A range of cementation parameters (UACP content, cementation solution concentration, and supply pressure) were screened, with follow-up reproducibility and optimization studies. Homogeneous compaction with high aggregate packing density was crucial for consistent cementation. A compressive strength up to 52.5 MPa with a cementation depth of 140 mm (and up to 57.4 MPa locally) was achieved—exceeding previous reports. These results indicate bio-concrete’s potential for prefabricated load-bearing building components as a partial replacement for traditional concrete.