Effects of microbial carbonate precipitation on transport properties of fiber cement composites

Fibers have been used to improve the mechanical and physical properties of cement-based material since the late 1960s. The inclusion of high-dosage and high-aspect ratio microfibers, however, introduces new interfaces between the fiber phase and the matrix phase that may alter the transport properties of fiber cement composites. This paper reports the effects of microbial carbonate precipitation (MCP) on the transport properties of fiber cement composites (FCCs). The results show that the transport properties of untreated FCC increase with fiber dosage as well as fiber aspect ratio due to higher porosity and better pore connectivity. MCP treatment greatly reduced the transport properties of FCC. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses confirm the precipitates were in the form of rhombohedral calcite, which suggests slower MCP due to the growing environment and culturing condition used in this study.