In parts of Connecticut and Massachusetts, foundations of some homes are cracking and crumbling. Failing foundations can reduce the market value of a home and lifting a house to replace and repour a foundation is an expensive undertaking. In response, some homeowners are defaulting on their mortgages and abandoning their homes. The culprit is pyrrhotite, which occurs in construction aggregate (crushed stone) that was used as a filler in concrete. When pyrrhotite is naturally exposed to water and oxygen, it breaks down to produce sulfuric acid and secondary minerals, including gypsum, which have larger volumes than the pyrrhotite they replace. The expanded volume of the secondary minerals cracks and degrades concrete.
|Title||Pyrrhotite distribution in the conterminous United States, 2020|
|Authors||Jeffrey L. Mauk, Thomas C. Crafford, John D. Horton, Carma A. San Juan, Gilpin R. Robinson,|
|Publication Subtype||USGS Numbered Series|
|Series Title||Fact Sheet|
|Record Source||USGS Publications Warehouse|
|USGS Organization||Central Mineral and Environmental Resources Science Center|