Microscopic analysis for the oxidation of sulphide-bearing aggregate.

Mortar samples were prepared with sulphide-bearing aggregates and tested for the potential of aggregate oxidation followed by sulphate attack. Scanning Electron Microscopy and its associated Energy Dispersive X-Ray analysis were used to analyze the developed phases in the tested samples to confirm that the obtained expansion is attributable to sulphate attack.  The Energy Dispersive X-Ray analysis helped identify sulphide phases in aggregates and evidence of sulphate attack in mortars.