Norway: A team at the Norwegian University of Science and Technology (NTNU) has shown the inadequacy of current methods for detecting pyrrhotite in aggregates used in concrete production. Pyrrhotite is sensitive to sulphate attack, causing degradation in concrete. However, current quality assurance methods, such as differential thermal analysis, optical microscopy and total sulphur measurement, fail to distinguish between pyrrhotite polytypes and concentrations. Concluding its paper published in the Construction and Building Materials Journal, the team instead recommended thermomagnetic analysis as a standard method. This measures magnetic susceptibility changes across heating cycles to identify and quantify pyrrhotite polytypes based on their magnetic transitions.

aggregates testing performance study research Norway Norwegian University of Science and Technology pyrrhotite sulphate attack