Transmission Soft X-ray Microscopy

Transmission soft x-ray microscopy is a high resolution technique which allows imaging of wet samples under normal pressure. As a result, reactions such as cement hydration and the pozzolanic reaction can be observed over time, providing information about reaction kinetics and microstructure formation. In addition, soft x-rays reveal information on the internal structure of the sample.

The x-ray images above, obtained using the transmission soft x-ray microscope XM-1, show the reaction of chemical grade silica gel in a solution of 0.7M NaOH + 0.1M CaCl2 after 11min.(left) and after 34 min. (right). The earlier image (left) shows the initial stages reaction, where the original silica gel particle is visible with some lath-like structures forming on the surface. The subsequent image (right) shows the development of a calcium silicate hydrate (C-S-H) product in the distinctive ‘sheaf of wheat’ morphology. The product and the structure are significant in the hydration of portland cement, the pozzolanic reaction, and the alkali-silica reaction. (Scale bar = 1 micrometer)

Credits:
Kimberly E. Kurtis, Georgia Institute of Technology (http://www.ce.gatech.edu/~kkurtis)
Paulo J.M. Monteiro, University of California, Berkeley (http://www.ce.berkeley.edu/~paulmont)
Werner Meyer-Ilse, Center for X-ray Optics, Lawrence Berkeley National Laboratory (http://lily.als.lbl.gov:8090/)
John T. Brown, Center for X-ray Optics, Lawrence Berkeley National Laboratory