Development of a risk assessment framework for pyrrhotite induced deterioration of concrete foundations in CT and MA

The use of pyrrhotite-rich aggregate in concrete foundations is linked to cracking induced by oxidation and expansion. Several factors influence the reaction rate and damage onset, including pyrrhotite content, concrete quality, and moisture presence. The development of a framework to link the kinetics and extent of reactions to damage requires a quantitative understanding of chemical reactions and physical conditions. This study presents the results of analyses conducted at 256 homes. Visual inspections for damage were complemented by analysis of 1017 samples for age, moisture content and chemical parameters. Statistical analysis identified total sulfur and sulfide content as the only variables strongly correlated with damage probability. However, the effect of the foundation age requires additional investigation, as the dataset showed a bimodal distribution with older homes linked to higher total sulfur and younger homes to lower total sulfur concentrations.