Northwestern Home Page NanoScale Cementitious Materials

Life is a cement trampoline
Howard Nordberg

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

Recent Publications

  1. Nanoscale characterization of cementitious materials, P. Mondal, S.R. Shah, and L.D. Marks, ACI Materials Journal 105, 174 (2008)
  2. 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)