My Ph.D. research centers around employing microorganisms to produce bio-cement that can be used as alternative traditional cement. This effort aims to advance the sustainability of underground engineering, which is a key approach to solving global problems facing society. In geotechnical engineering, which is a sub-discipline of civil and construction engineering, ground improvement is a major area that requires sustainable development on a large scale as it often causes environmental issues. Specifically, toxic effects on the groundwater quality are reported due to grouting, while the cement production industry, which produces widely used material for stabilizing soil and rock, is a major industry emitter of CO2. Concrete currently accounts for 8-12% of the carbon dioxide being emitted into the atmosphere, a big contribution from one industry. Moreover, the expected increase in the global population will increase the effects of the construction industry on the environment.
Because the construction industry is a significant source of CO2, it has the potential to dramatically reduce its impact and tackle some global crises. Effective use and maintenance of underground spaces can contribute to solve global problems society now faces, including environment degradation by preserving green spaces, air pollution that is related to transportation by providing roadway tunnels, and protection against natural disaster such as flooding by providing flood relief tunnels, among many other global problems. However, underground construction often requires support systems and ground improvement in which cement mostly is a key element. Thus, using eco-friendly alternatives to ordinary cement in underground applications will help to achieve a dual sustainable impact of using the underground spaces.
My current research is characterized by its interdisciplinary nature that draws knowledge from geo-biotechnology, microbially induced calcite precipitation (MICP), as an innovative technology to produce sustainable cementation material suitable for subsurface applications, instrumentation and monitoring using a geophysical tool including nuclear magnetic resonance (NMR) along with imaging techniques including micro computed tomography (μCT scan). Furthermore, my research marks the first attempt to study the failure mechanism of the bio-treated fracture rock. Understanding the failure mechanism is crucial to design and stability assessments of rock construction, including tunneling.
The data and results generated from my Ph.D. research were prepared for publication in different academic journals. A manuscript based on NMR measurements of fractured sandstone sealed with microbially induced calcite precipitation: hydraulic properties and cementation distribution was submitted to Journal of Geotechnical and Geoenvironmental Engineering, ASCE. Another manuscript based on experimental study on the tensile behavior of MICP-based grouted sandstone under Brazilian test conditions: bio-cementation content and fracture orientation effects is under review for publication in Acta Geotechnica Journal. Moreover, a manuscript based on a comprehensive study of MICP- based grouted rock: strength and fracture evolution under uniaxial compression is under preparation to be submitted for publication to either Rock Mechanics and Rock Engineering journal or International Journal of Rock Mechanics and Mining Sciences.
It is worth mentioning, my research falls within one of the 14 grand challenges for engineering in the 21st century identified by National Academy of Engineering (NAE): restore and improve urban infrastructure, which is similar to goal #11 of the United Nations Sustainable Development Goals (SDGs), to build sustainable, inclusive, safe and resilient cities and communities. it also has implications for carbon capture, utilization and sequestration (CCUS). CCUS technology is on the Greenhouse Gas Pollution Reduction Roadmap of the state of Colorado. The roadmap aims to achieve the state target of 90% of GHG reduction by 2050 from a 2005 baseline. This demonstrates my commitment to sustainability and my contribution to climate action as part of my career goals.
My Ph.D. research has been previously recognized with different awards and scholarships including:
• Colorado Association of Geotechnical Engineers Award for the technical research on topics related to the practice of geotechnical engineering in the state of Colorado
• Rocky Mountain Chapter of the American Concrete Institute/ Jean-Claude Roumain Memorial Scholarship for research and development for advancement of concrete as a sustainable construction material
• Gavora Thirst for Knowledge Fellowship in researching environmental issues
• Association of Energy Engineers scholarship
• Women Transportation Seminar (WTS) Colorado Chapter scholarship
• Finalist of American Rock Mechanics Association (ARMA) international research contest, which will occur in February 2023.
Furthermore, During the pandemic, my research, which is purely experimental was on hold due to the stay-at-home-order and then safer-at-home orders. Therefore, I decided to use my time effectively by deciding to step into the underground engineering industry to have a more inclusive understanding on the benefit of bringing together the two sectors, academia and industry. I worked as part time tunnel engineer where I involved in projects advancing the underground industry in the U.S and Canada. Some of the key projects that I involved in, Metropolitan Tunnel Redundancy Program, Massachusetts, USA; Mill Creek Tunnel Project/ Flood relief Tunnel, Dallas Texas; New Braunfels Utilities: Seguin Water Supply Trenchless Crossing, New Braunfels, Texas; Eagle Mountain-Wood Fiber Pipeline Project, Vancouver, Canada; and Montreal Airport Transit Station Program, Montreal, Canada.
My future research direction is building on my current expertise in bio-mediation ground improvement to improve the performance of bio-cemented fracture rock by investigating potential ways to increase the ductile behavior of the bio-cemented rock. I’m also aiming to employing other bio-inspired methodologies in application of fracture rock reinforcement and bio-based self-healing concrete and elucidate the mechanism of the bio-cementation process in a comprehensive study at a micro level. Understanding the effect of underground projects on the sustainable, economic and social aspects of the major cities is another research area I would like to focus on.
Maryam Alahmar
Ph.D. Student in Civil EngineeMines email address:
malahmar@mines.edu
Website (or social media page):
https://www.linkedin.com/in/maryam-alahmar-6851ab128/ring