EMBRACE-EAR-Growth: Rock degradation - microscale approach mineral by mineral (RDM2 )

About This Grant

Studying mineral interactions in rocks subjected to elevated and cyclic temperatures can improve the economic competitiveness and the national security of the U.S. In fact, the understanding of rock degradation processes can help accelerate the extraction of current and alternative resources (e.g., energy and minerals), improve risk identification associated to land movement events, and expand the skilled workforce in the U.S. Finding factors weakening rock minerals can help facilitate drilling operations though deep rock formations, which are typically found in nuclear storage units, power plants, and mines. Conversely, refined information on rock decay processes under temperature can help assess vulnerability on deep rock, exposed rock, frozen rock, and snow-covered surfaces whose instability can cause catastrophic events. Additionally, measuring rock responses based on the behavior of their mineral components could provide transferable methodologies to study composite materials like concrete, whose structure could also be exposed to thermal fracturing induced by seasonal changes. Due to the strong participation of students in this project, its execution also aims to attract young generations to pursue careers in the STEM fields. The overall goal of this research is to develop new links between rock mechanics and geology by providing a fundamental understanding of the role of mineral interactions on rock degradation under temperature cycles and elevated temperatures. To accomplish it, three subgoals have been outlined. They include: (1) measuring the contribution of mineral strength into rock strength, (2) correlating mineral orientations with mechanical properties of rocks, and (3) measuring the evolution of mineral interphases and fracturing mechanisms within rock composites. As such, subgoal one involves nanoscale experimentation on mineral interactions, subgoal two involves both nanoscale and mesoscale testing on pure minerals (e.g., albite, biotite, quartz) and rock composites, and subgoal three combines (i) nanoscale mechanical testing on localized inter-mineral discontinuities, (ii) microscopy techniques on mineral fractures, and (iii) simple numerical models refining boundary conditions for mineral interactions in granitic rocks. Thus, through experimentation and modeling, this project will bring light into understanding the influence of mineral content, mechanical contrast, mineral orientations, and temperature conditions on the mechanical response of rock composites. The unprecedented data on mineral interactions and their associated analyses on rock degradation mechanisms, stemming from this work, will be applicable to both shallow and deep rock formations. As such, this project also aims to contribute to refining risk mitigation strategies both for engineering infrastructure and for geological formations. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.