Tadhg Dornan is a PhD researcher in the iCRAG raw material research spoke. Tadhg graduated from Trinity College Dublin with an honours degree in Geology in 2016 and soon after started a PhD under the Supervision of Dr. Robbie Goodhue. His research mainly focuses on pyrite, a commonly occurring iron sulphide mineral, and its role in the deterioration of concrete when oxidised. As part of his research, Tadhg will attempt to elementally analyse the grains pyrite found in the concrete of damaged properties and try and fingerprint a quarry source for the material.
Crushed rock aggregates are a large portion of the materials used in houses across Ireland: in concrete blocks and as fill used under concrete floors. However, these rocks can contain reactive materials, such as the mineral pyrite. Pyrite is mainly composed of iron and sulphur and when it encounters moisture it oxidises which sets off a reaction chain resulting in the expansion of the aggregate. This expansion or “pyritic heave” causes cracking and damage to people’s homes. My work focuses on fingerprinting the source of this expansive pyrite and investigating whether the crystal shape or elemental composition affects pyrites reactivity.
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 elemental (As, Mo, Pb, Ag) analysis using SEM-EDS and LA-ICPMS will carried out 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 where the quarry source is unknown, to a specific quarry. In addition, the project will also investigate what effect the crystal shape and elemental composition of the pyrite has on its reactivity.
- Postgraduate Researcher
- Supply of Raw Materials
- Building Materials