Novel Pyrrhotite Detection Method in Concrete Aggregate

Pyrrhotite is an unstable iron sulfide found in some aggregates; its oxidation in concrete has devastating effects on the concrete-based infrastructure. The proposed project will further develop a robust and resilient nondestructive tool that employs NMR relaxometry for detecting pyrrhotite and identifying pyrrhotite-related degradation. NMR relaxometry can also identify other mechanisms of concrete deterioration (alkali-silica reaction, sulfate attack, freeze-thaw damage, carbonation, etc.). The new pyrrhotite-related capability would allow for more comprehensive field identification of the prevalent mechanisms and the extent of concrete deterioration. The base Phase II project will refine the system design, operation and data analysis methods, improve and validate the system calibration, consolidate the system components, devise an interface for convenient field operation and real-time data analysis, evaluate the system in field, and assess its performance versus the Navy requirements. The Phase II Option will use the experience of the base Phase II project to further refine the system design and optimize its operation, integrate the system capabilities for evaluating the pyrrhotite-related and other mechanisms of concrete deterioration, validate the integrated system capabilities for comprehensive condition assessment of the concrete-based infrastructure in laboratory and in field, and assess the competitive merits and the commercial prospects of the technology.