Life is a cement trampoline
The fundamental properties of concrete are affected by material properties at the nano-scale.
However, the nano and microstructure of the most important hydration product in cement paste,
calcium silicate hydrates (C-S-H, with C = CaO, S = SiO2, and H = H2O) is not well understood.
Our research is to characterize the properties of cementitious materials using different imaging
techniques namely optical microscope, Scanning Electron Microscope and Atomic Force microscope
and evaluate the local mechanical properties of different phases of hydrated cement paste.
This will provide information from a length scale of micrometer to nanometer. For the determination
of local mechanical properties, a nanoindenter with unique advantage of in-situ SPM imaging that
allows pre and post-test observation of the sample is being used. We are also investigating the
changes in nano-scale properties with the addition of different commonly used Supplementary
Cementitious Materials like silica fume and fly ash.
Figure 1: 4.7 mm x 4.7 mm AFM topography image of C-S-H gel
Figure 2: 10 mm x 10 mm image of C-S-H gel close to unhydrated cement particle after indentation
- Nanoscale characterization of cementitious materials,
P. Mondal, S.R. Shah, and L.D. Marks, ACI Materials Journal 105, 174
- A reliable technique to determine the local mechanical properties at the
nanoscale for cementitious materials,
P. Mondal, S.P. Shah, and L. Marks,
Cement and Concrete Research 37, 1440 (2007)