Influence of molding process on mechanical properties of sandstone cemented by microbe cement

A new generation of cement, microbe cement has been developed due to the ever increasing awareness of environmental protection. Microbe cement is a new strengthening technique based on microbiologically induced precipitation of calcium carbonate. This paper confirms the feasibility of microbe cement binding loose sand particles and presents results from a laboratory research on the influence of molding process (non-pressure molding, pressure molding, discontinuous non-pressure molding and pumping molding) on the mechanical properties of sandstone microbe cement bound. The results showed that the ways of molding procedure had a strong influence on the mechanical properties of bio-sandstone. The strength, which was up to 12.0 MPa, of sandstone microbe cement bound by adopting pumping molding process was higher than other three processes. Meanwhile, Scanning electron microscope (SEM) image analysis technique was adopted to measure the corresponding variation of porous characteristics caused by different molding processes. The results indicate that the microstructure of bio-sandstone adopted by pumping molding has lower porosity and higher content of precipitated calcium carbonate than other three molding processes.