Scientist Visits Micromeritics and Delivers Lecture on the Use of Atomistic Simulation Techniques in the Research Effort to Develop Revolutionary Concrete Materials - 4/11/2011
Recently, Dr. Roland J.-M. Pellenq, visited Micromeritics’ corporate facility in Norcross, GA at the invitation of Dr. Jacek Jagiello and Dr. Jeff Kenvin. After a tour of the company’s state-of-the-art manufacturing facility, Professor Pellenq presented a lecture titled “The Hardened Paste, CSH, - from Nano to Micrometer” highlighting his work as a visiting professor at the MIT Concrete Sustainability Hub. This facility is involved in important research aimed at developing sustainable concrete structures that exhibit superior strength and durability with reduced CO2 emissions.
The MIT team has discovered that calcium-silica-hydrate (CSH), the paste that forms and quickly hardens when mixed with water, is a hybrid material that shares characteristics with crystalline structures and amorphous structures such as glass or ice. Breaks in the silica tetrahedral create small voids in the layers of calcium oxide where water molecules attach. These irregularities in the otherwise regular geometric structure at the atomic scale give concrete structures the flexibility to stretch or compress under stress. However, until recently, decoding the three-dimensional structure of cement hydrate eluded researchers.
Dr. Pellenq was able to determine the correct atomic weight, exact chemical shape and structure of CSH using an atomistic modeling technique called the grand canonical Monte Carlo simulation. With an accurate model for the geometric structure of the basic unit of cement hydrate, the MIT team performed tests that validated its accuracy. “This gives us a starting point for experiments to improve the mechanical properties and durability of concrete. For instance, we can now start replacing silica in our model with other materials,” said Pellenq.
Dr. Pellenq is currently a visiting professor in the Department of Civil and Environmental Engineering at the Massachusetts Institute of Technology. Since 2003, he has been the Director of Research at the Interdisciplinary Center of Nanosciences which is part of the French National Center of Scientific Research and Marseille University, Marseille, France. His research has focused on using atomistic simulation techniques to study the stability and mechanical properties of layered inorganic materials and the thermodynamics of confined molecular and covalent fluids in porous materials. He has also had numerous papers published in peer-reviewed international journals.
Micromeritics welcomed the visit in an ongoing effort to stay current with ground-breaking research and to educate its employees on the wide variety of applications for its instruments. In business since 1962, Micromeritics manufactures automated analytical laboratory instruments that measure physical characteristics of powder and solids for fundamental research, product development, quality assurance/control, production, and process control applications. Measurements obtained include particle size, particle shape, surface area, pore volume, pore size and pore size distribution, material density, catalytic activity, and temperature-programmed reactions.