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 and its subsequent sulphate attack. Scanning Electron Microscopy (SEM) was used as a tool to analyze the developed phases in the samples to confirm that the obtained expansion is attributable to sulphate attack. The Energy Dispersive X-Ray analysis (EDS) of the SEM helped to identify sulphide phases in aggregates and the presence of evidence of sulphate attack in mortars exposed to conditions that promote oxidation and sulphate attack. Ettringite and Thaumasite were detected and confirmed by EDS in the mortars with sulphide-bearing aggregates suggesting that the test conditions are suitable for reproducing the damaging mechanism of sulphide oxidation.

Elmosallamy, Monaand Shehata, Medhat H.Microscopic analysis for the oxidation of sulphide-bearing aggregate, Journalof Microscopy, SN -0022-2720, https://doi.org/10.1111/jmi.13065