Bio-Inspired Erosion Countermeasure: Microbial Induced Calcite Precipitation

ASEC 105, 12-1 pm Friday, November 4, 2016

Dr. Julian Tao is an Assistant Professor in the Department of Civil Engineering. He has a keen interest in exploring fundamental mechanisms and innovative countermeasures to emerging infrastructure challenges, particularly in the broad area of sustainable and resilient geotechnical engineering. Select topics include sustainable geotechnics, bioinspired geotechnics and computational geomechanics. His career goal is to establish a research platform for bioinspired, sustainable and smart geotechnics (BiSS Geo), where sustainable solutions to a variety of geotechnical problems can be sought at the boundaries of biology, mechanics and engineering.

Presentation Summary

Surface erosion is relevant to a variety of infrastructure problems such as bridge scour, roadway shoulder erosion, coastal erosion, and riverbank and slope stability. For example, about 60% of all bridge failure cases were caused by local scour and other hydraulic related issues. This research investigates the feasibility of using microbial induced calcite precipitation (MICP) as an erosion countermeasure. MICP is a natural phenomenon where calcite precipitation occurs as a consequence of microbial metabolic activity. The precipitated calcite modifies the soil fabrics and provides additional bonding force between soil particles, thus improving the erosion resistance. A standard soil, Ottawa graded sand, was treated with bacteria, Sporosarcina pasteurii, in a full-contact reactor where the soil in a fabric mold is fully immersed in the bacteria and cementation solution. The treated soil samples were tested in a flume to investigate the erosional behavior; both surface erosion and bridge scour tests were conducted. It was found that, while the untreated soil is highly erodible, the erosion of the treated sand is negligible under the test situations; but some concerns are raised regarding to practical applications. Future efforts will be made to identify alternative treatment procedures which are more applicable to the field.

Anyone is welcome to attend this research presentation; feel free to bring a brown bag lunch!