Fracture of Porous Materials Induced by Crystallization of Salt

The penetration of salt into porous materials is known to have deleterious effects, often resulting in fracture. The damage process begins with a saline solution penetrating the porous network by way of capillary action. This is followed by supersaturation of the saline solution, which may result in the formation of salt crystals. In turn, these salt crystals induce pressure on the pore walls. Though the stress generated by the crystallization of salt in a single pore alone is unlikely to result in fracture, if the crystallization region is large enough, the combined effects can lead to fracture. This thesis will first provide an overview of the crystallization process and then focus on the factors leading directly to fracture. The thesis will examine various key processes proposed by researchers, identify elements that have not yet been explored, and finally propose a cohesive outline of the processes responsible for fracture. Thesis Supervisor: Franz-Josef Ulm Title: Professor of Civil and Environmental Engineering Acknowledgements The completion of this thesis marks the culmination of my two years at MIT. Two years that, without a doubt, were the most personally and academically challenging years of my life. I could not have made it to this point of graduating from this esteemed institution without the help and support of a number of people. Firstly, I am most appreciative and indebted to my thesis advisor, Professor Franz Ulm, for his direction, his patience, his availability, and for relaying the confidence that I could tackle this difficult subject which, on more than one occasion, I feared was well beyond my realm of competence. I'd also like extend my thanks to Dr. Eric Adams, for considering my transfer to the CEE M.Eng program on such short notice. And to my course advisor, Professor JJ Connor, for all the advice. And thank you to my M.Eng classmates (AKA, the moosheads) for filling me in on my deficient knowledge of civil engineering, and for your humor and comradeship. I must express my acknowledgements to the National Science Foundation for awarding me their generous graduate fellowship. And despite my arduous couple years at MIT, I'd like to express my sincere appreciation to my original advisor at MIT, Professor Raul Radovitzky, if not for whom, I most probably would have gone to an unnamed university in the Bay Area of California. I am most grateful to Raul for his being the first encouraging voice at MIT, for his recruiting efforts, and more importantly, for his understanding, and for bearing with me as I attempted to figure out what direction to take my education. I am also very grateful to Leslie Regan, from the mechanical engineering graduate office, for being most helpful in facilitating both my coming to and adjusting to MIT. From the day I was admitted to MIT until my "departure" from the mechanical engineering department, Leslie has been extremely supportive, friendly, and just altogether fantastic. Additionally, I am most obliged to all the professors (too many to list) that took the time to talk to me about their research and welcomed me to join their labs while I was exploring my interests. Thanks is due to as well to all the graduate students who candidly gave me the rundown on what it was really like doing research with a number specific professors. Many thanks to my former labmates in EBM: Alex Thierez and Jeff Dahmus; and to all my labmates in Telac, my first lab at MIT, with special mention of those I shared a cubicle area with: Antoine Jerusalem, Daniel Tam, and Nathan Wicks. Thank you for your companionship, for all your coaching, and for encouraging me to explore other options in an effort to figure out what I want to do. I might not have applied to MIT, or perhaps even graduate school, let alone won the NSF fellowship, if not for my undergraduate advisor, Professor Louis Whitcomb. I cannot believe my good fortune in having the most wonderful advisor a student could possibly hope for. Professor Whitcomb not only provided me with optimal direction through out my undergraduate years at Johns Hopkins, but he actually pushed me to excel well beyond my highest expectations, not allowing me to settle for anything less my best effort, and believing that I could achieve more than I myself could ever imagined I could. Furthermore, he served as constant inspiration for me as an example of a cutting edge researcher and a dedicated first rate teacher who was always available for his students. I'd also like to acknowledge all of my other professors at Johns Hopkins for providing me with a superb education. Though I'm not sure it's possible to ever be adequately prepared for graduate school in the mechanical engineering department at MIT, I think Johns Hopkins brought me as close to being prepared as possible (in the academic sense at least). Special thanks to Professors Roger Ghanem, Jean-Frangois Molinari, Allison M. Okamura, William N. Sharpe, Ilene J. Busch-Vishniac, and Dr Andrew Conn, for their advice and encouragement outside of the classroom. I owe my sanity to all my friends who maintained contact despite my enrolling at MIT. Firstly, to the Lefferts Crew: Esty Kaminker, Tzipora Rivkin, and Bella Schapiro for their nearly two decades of friendship and contributing to who I am and to where I am today. I'm also particularly grateful to the friends who traveled to visit me in Cambridge: Michelle Clark, Chumi Lein, Pnina Levitz, and Shana Olidort, as well as to Greg Burton, Danielle Soya, and Brian Yagoda, for making a point to meet up with me when they were in town. And to my other friends who provided moral support from afar: Nava Chitrick, Miriam Fliegner, Liba Ginsburg, Francine Katz, Agatha Monzon, Kimberly Rosendorf, Dini Schwartz, Yaakov Shaul, Sarah Spinner, Soshie Weingarten, and anyone else I might have forgotten... Finally, I'd like to thank my family, and my parents most of all for continually supporting me without reservation, despite my going on a track which is not necessarily encouraged by the community. I am especially grateful to my mother. Among countless other things, thank you so much for gladly putting up with my constant barrage of phone calls, and not only taking the time to listen to me, but making me realize, on a number of occasions, that my life wasn't ultimately falling apart for real this time, and things would work out somehow. Table of