A study on the cementation interface of bio-cement

X-ray diffraction (XRD) analysis was carried out on a new kind of bio-cement based on phosphate-mineralized microbes to confirm the composition of phosphate products, i.e. Ca10(PO4)6(OH)2 and BaHPO4. Meanwhile, the bio-cement was researched in terms of the cementation interface. The results show that the interfacial bonding strength of bio-phosphate cement is lower than bio-calcite cement in the scratch experiment. The microstructure between calcite and loose sand particles was analyzed by X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR). The results of XPS and NMR analysis confirm that the microbially-induced precipitation of minerals in loose sand particles means they interact with other particles to generate bonding effects, which plays a role in the binding function between loose sand particles and bio-cement.