Polarization-fluorescence Microscopy in the Study of Aggregates and Concrete

Abstract

Concrete structures may develop deleterious damage, which significantly reduces service life, structural integrity, and safety, posing serious issues in large or otherwise critical infrastructure. Routine petrographic assessments, including microstructure, texture, and fabric, of concrete and its (gravel and sand) aggregate and binder constituents in thin section using polarization-fluorescence microscopy (PFM) enables the unequivocal identification of features that would otherwise remain hidden in conventional petrography. Rigorous preparation procedures preserve original microstructural details, make preparation artefacts recognizable, and ensure that the fluorescent emission can be quantified. This contribution outlines the preparation of fluorescence-impregnated thin sections and elaborates on the application of PFM to damaged concrete, with further examples from selected rock types commonly used for concrete aggregate.