Influence of number of injections on mechanical properties of sandstone cemented with microbe cement

Microbe cement, as a new green binder, relies on microbial-induced calcium carbonate precipitation and could consolidate loose particles to a whole body (bio-sandstone). The mechanical properties of sandstone cemented by microbe cement for different numbers of injections were investigated. The results show that the compressive strength of bio-sandstones increases with injection number: the average compressive strength of bio-sandstones could be up to 6·1 MPa after 14 injections of microbe cement. In addition, the rate of increase of compressive strength decreases with an increase in the number of injections. The microstructure of bio-sandstones with different numbers of injections was analysed by means of scanning electron microscopy. The results indicate that the microstructure of the bio-sandstones became increasingly dense with an increase in microbe cement injections.