Presentation materials
One gram of soil can contain up to 100 million to 1 billion microrganisms and up to 1 million different species of microorganisms. Despite this fact, geotechnical engineers have, until fairly recently, ignored biological activity in the soil or possible biological amendments that could be introduced. Over the last ten years research has focused on bioaugmentation strategies (i.e. the injection...
Bacterial colonization and the spread of biopolymer, gel-like material, on porous media are known to decrease permeability by several order of magnitude and to cause bioclogging thereby altering the hydraulic flow systems of porous media. Attention to microbial bioclogging has been increasing owing to the increasing demand of microbial soil treatment and soil improvement. Successful microbial...
Bio-mediated ground improvement technologies harness subsurface biological and chemical reactions to improve the engineering properties of soils with reductions in detrimental environmental impacts when compared to conventional methods (Seagren and Aydilek 2010; DeJong et al. 2013). One such technology, Microbially Induced Calcite Precipitation (MICP) or bio-cementation, has received...
Microbially Induced Carbonate Precipitation (MICP) through the urea hydrolysis reaction has been extensively studied in the lab and implemented at field-scale several times, most notably for fracture sealing (Cuthbert et al., 2013; Phillips et al., 2016), for erosion control (Gomez et al., 2015), and for ground improvement (van Paassen et al., 2010). Grouting strategies used in industry are...
Microbially induced desaturation and precipitation (MIDP) via denitrification has the potential to mitigate earthquake-induced liquefaction by two mechanisms: biogenic gas production to desaturate and dampen pore pressure changes in soil and calcium carbonate precipitation to mechanically strengthen soil. Lab-scale tests have demonstrated that both desaturation and precipitation are effective...
The biogenic gas behavior in porous media, which includes bubble nucleation and growth, migration, coalescence and trapping is affected by the gas generation rate, distribution of reactive sites and the pore scale characteristics of the sediment. In this study, experiments are performed using a micro-fluidic chip in which different gas bubble behavior mechanisms in the porous media are...
Ancient stone relics and historic buildings are often subject to significant degradation. The protection and restoration of these monuments is extremely urgent. Here, a method of building repair based on microbial induced carbonate precipitation (MICP) has been tested on marble stone. In previous research, microbial mortar (stone powder treated by MICP) was tested as a filling material to...
Worldwide demand for new and sustainable approaches to geotechnical engineering problems has generated novel research opportunities in the emerging field of bio-mediated soil improvement. The most widely researched of these processes is microbially induced calcite precipitation (MICP), which has shown promise for a wide variety of engineering applications. Initially MICP was accomplished by...
