A new publication titled “High-fidelity and high-resolution phase mapping of granites via confocal Raman imaging” was published in Scientific Reports in April 2021.
Granites are one of the most abundant silicates on Earth’s crust, and they can often be found in concrete mixtures where siliceous aggregates have been used. Understanding the mineral phase composition of these complex rocks is a key requirement to predict their tolerance to long-term radiation in a nuclear power plant. However, obtaining accurate phase maps from traditional petrographic methods as well as newer elemental mapping methods has a series of limitations. Here, we report a methodology that allows direct mineralogical mapping and fingerprinting using Raman spectroscopy and imaging. Our results enable high-resolution and high-fidelity spatial mapping of minerals at the sub-micron scale, opening up pathways to rapidly assess and quantify the mineralogical composition of samples that require minimal sample preparation.
This is the first article from our group’s Ph.D. candidate Krishna C. Polavaram. Congratulations Krishna!
A new publication titled “Nanoscale Ordering and Depolymerization of Calcium Silicate Hydrates in the Presence of Alkalis” was published in The Journal of Physical Chemistry C in September 2019.
Sustainable cements like alkali-activated materials often contain non-negligible amounts of alkalis (Na or K) which significantly influence the resulting material’s performance. However, the precise role of these alkalis is not fully understood. In this publication, using a combination of X-ray PDF and NMR, we present evidence on the silicate polymerization and the structure of the CNASH gel. Additionally, we also report novel data on the long-range atomic ordering of a series of 45 synthetic gels.
A new publication titled “Dissolution Kinetics of Calcined Kaolinite and Montmorillonite in Alkaline Conditions: Evidence for Reactive Al(V) Sites” was published in Journal of the American Ceramic Society in July 2019.
Using solid-state Nuclear Magnetic Resonance spectroscopy and Inductively-coupled Plasma – Optical Emission Spectroscopy, we followed the dissolution kinetics of calcined kaolinite and montmorillonite. It was shown that dissolution kinetics are correlated with pozzolanic reactivity and dissolution rates are strongly influenced by the presence of reactive Al(V) sites.
A new publication titled “Symmetry-Induced Stability in Alkali-Doped Calcium Silicate Hydrate” was published in The Journal of Physical Chemistry C in May 2019.
Using first-principles quantum chemistry calculations on the model crystalline phase clinotobermorite, it was shown that there is a strong interplay between the thermodynamic stability of alkali-doped C-S-H and the symmetry of the alkali atoms in the structure. The article can be accessed here.