MICROSTRUCTURAL CHARACTERISATION OF CEMENTITIOUS MATERIALS
The course presents latest developments of advanced characterization on microstructure of cementitious materials, according to the latest methodology developments. IT is based on the book produced by the Nanocem team and edited by Karen Scrivener, Ruben Sneling and Barbara Lotenbach, which for the first time presents in an organized way a comprehensive methodology for microstructure characterization of cement-based materials.
Prof. Scrivener (EPFL – https://people.epfl.ch/karen.scrivener ) has been the most influential researcher in cement-based materials science for more than a decade. She is editor of the Cement and Concrete Research and scientific coordinator of Nanocem, the European network on cement-based materials that has been redefining the fundamentals of cement technology.
The course was organized by the National Institute on Advanced Eco-Efficient Cement-Based Technologies (CEMtec), funded by Fapesp and CNPq.
The course contents are:
- SEM – EDS
- TG (by V.M. John)
- Proton 1H NMR
Microstructural characterization of Cementitious materials – Introduction – 35 min
This lecture Prof. Scrivener presents an overview of the difficulties of characterization the microstructure of multiphase cementitious materials. A overview of the major characterization techniques is presented, including cement storage, sample mixing and preparation, techniques to stop hydration, and the use of chemical shrinkage as an indicator of hydration.
X-ray Diffraction (XRD)
Prof. Scrivener discusses in detail the use of XRD in for the characterization of cementitious materials microstructure. It presents the fundamentals of the XRD, the latest advances including the Rietveld method, which did substitute the Bogue formula on the estimation of the clinker mineral phases. Details of sample preparation, including hydration stoppage techniques as well as advanced techniques as combination of XRD with selective dissolution of phases. Quantitative phases analysis is discussed in detail. Several examples are given.
Electron Microscopy of Cementitious Materials (SEM & TEM)
Prof. Scrivener presents a summary of her large experience on pushing forward the use of SEM on the cement-based materials microstructure. Fundamentals of SEM technique are presented. The use of secondary, backscattered and X-rays demonstrated. Sample preparation, a major difficulty, is discussed with more detail and practical tips are given. Examples of interpretation of results, including the use of image analysis and statistics, as well combination with other techniques are given. At the end Prof. Scrivener makes a short introduction of transmission electronic microscopy (TEM).
Prof. Vanderley John (USP) presents a set of slides produced by Barbara Lotenbach, Klartjee de Werdt the fundamentals of thermogravimetry analysis applied to cement, including sample preparation and analysis techniques, which is always a crucial aspect of testing. Possibilities and limits of phase quantification as well as most common mistakes on the analysis are exemplified. The slides were produced by
Porosity by Proton, 1H Nuclear Magnetic Resonance
(Proton 1H NMR) – 35min
In this last module, Prof. Scrivener presents the Porton 1H NMR, the most recent, and less known techniques, that can be used, among other things, to quantify cementitious materials porosity. Details of the test method are presented and several examples are given. Systematic comparison with mercury intrusion porosimetry is presented.