Introduction to enhanced materials characterization using PhAse Recognition and Characterisation (PARC)

Sustainability has become a major consideration in the selection of raw materials for development of new building materials. At the same time in many countries legislation imposes strict limitations on landfilling of waste giving strong impetus to find options for re-use of such materials. These conditions together have been powerfully driving the development of building materials based on industrial by-products and civic waste streams. This direction of research is given credibility by established successful by-products, like Granulated Blast Furnace Slag and fly-ash, being constituents in cement worldwide.

Unlike Blast Furnace Slag and Fly Ash, the nature of many other by-products and civic wastes is poorly constrained. Materials can be highly heterogeneous, consisting of complex phase assemblages with unexpected properties concerning leaching behaviour, volume stability or have other issues. Often it is unclear which reactivity can be expected, requiring extensive characterization in order to establish potential use.

Since material properties derive from the underlying phases and microstructure we have started to fully quantitatively characterize these. The methods we use are powder-XRD with Rietveld analysis for phase amounts, in combination with SEM-EDS Spectral Imaging for phase composition and distribution. The methods are complementary, with Phase mapping (PARC) essential to characterize amorphous constituents such as glasses as well as trace element incorporation. PARC has the benefit of neither requiring prior sample knowledge, nor reference spectra, or being limited in number of Principle Components as with multivariate statistics. PARC and Rietveld will be shown to provide a comprehensive characterization of heterogeneous by-products.