XRD,  thermal analysis,  SEM, and TEM, are some of the common characterisation methods 

I'm an analytical chemist by training, so I've used a range of techniques over the years (and the project has been updated to reflect this). Often this has been to try and develop the techniques for application in cement science (this was particularly the case for Raman spectroscopy and X-ray photoelectron spectroscopy).

However, more recently the group has focused on the techniques which Joe has mentioned in his answer. Thermal analysis provides quantitative data on the portlandite and calcite contents, which can then be used to determine the degree of hydration of the cementitious materials. Scanning electron microscopy has been used to examine the microstructure (pore structure, degree of hydration and potentially C-S-H morphology). XRD is fine for pure C-S-H systems or for looking at some of the other phases in hydrated cements, but is not really useful for looking at the C-S-H in a "real" cement system.

For me, the main point has always been to think about why a particular technique might be useful and to think about what information it is that you need to gain about the system,. This should define the techniques used.