The objective of this collaborative ASU-Lehigh University project is to explore the potential of ureolytic calcite precipitation as a practical means of improving the capacity of vertical support elements for foundations in sands and silts. Enhancement of vertical elements for foundation support holds promise as the first practical application of biologically induced carbonate precipitation in geotechnical engineering. Elements of the work include exploring the use of agriculturally-derived urease enzyme as the catalyst for calcite precipitation rather than microbially-derived urease (the method employed in all calcite precipitation studies reported to date) and exploring the use of electro-kinetics to remove deleterious ammonia by-products of the precipitation reaction. The limited extent of the improvement zone required to enhance vertical foundation support elements, including stone columns, aggregate piers, deep soil mixed columns, drilled piers, and driven piles, mitigates problems associated with mass stabilization of soil by induced carbonate precipitation. The use of agriculturally-derived urease can further mitigate some of the problems encountered in mass stabilization and extend the range of soils that can be stabilized by induced carbonate precipitation into the silt-sized particle range. Practical application of ureolytic carbonate precipitation as a ground improvement technology and extension of the range of application of induced carbonate precipitation from relatively clean sands to soils with silt-sized particles are potentially transformative accomplishments, accelerating the development and implementation of biogeochemical ground improvement techniques and spurring further innovative developments in the emerging field of biogeotechnical engineering. ASUs scope of work on this project would include bench-top column tests and model tests in a tank approximately 2 ft wide by x 2 ft long by 1.5 ft high in the ASU geotechnical laboratory using the agriculturally-derived urease.
|Effective start/end date||9/1/12 → 8/31/15|
- National Science Foundation (NSF): $190,442.00