Title: Fingerprinting and assessing the reactivity of past and future aggregates
Researchers: Tadhg Dornan, Dr Robbie Goodhue
This research project aims to develop methods of fingerprinting quarry sources using pyrite in aggregate and to investigate the reactivity potential of pyrite. Detailed major (stoichiometric) and trace element (As, Mo, Pb, Ag) analysis using SEM-EDS and LA-ICPMS to characterise the elemental composition of pyrite. It is hoped that a database can be created that will allow matching of a specific sample from the sub-floor of a house, to a specific quarry location. In addition to this, the project will also investigate what effect the crystal morphology and elemental composition of the pyrite has on its reactivity with host aggregate.
The pre-existing knowledge on the reactivity potential of pyrite relates mainly to the oxidative process and subsequent sulphate formation. This work details key aspects of the project, such as the critical amount of pyrite that is needed to generate aggregate expansion and how the different crystal morphologies of pyrite accelerate or inhibit the oxidative process. However, there is no database for the major or trace element composition of pyrite for rock aggregates in Ireland. Therefore, this thesis will contribute to scientific knowledge by geochemically characterising Irish pyrite using both SEM-EDS and LA-ICPMS analytical techniques