UConn Team Diving Deep Into Crumbling Foundation Research

STORRS, CT — A crew at the University of Connecticut making progress on determining just why thousands of north central and northeastern Connecticut homeowners have been living in homes with faulty foundations.

The homes in question were built between 1983 and 2015 are potentially sitting atop faulty concrete foundations. The research is utilizing nearly $7 million in federal grants from the National Institute of Standards and Technology in the form of four grants, and a team from the College of Engineering is working "to better understand the effects of the concrete-degrading mineral pyrrhotite."

When exposed to oxygen and water, pyrrhotite expands, triggers additional reactions inside the concrete and can cause a slow deterioration of a home’s foundation.

Kay Wille, an associate professor of materials science and engineering and civil and environmental engineering said increased use of concrete over the past few decades have depleted the supply of good quality aggregates.

In the case of the region, contractors used a concrete aggregate that was unknowingly mixed with the mineral pyrrhotite from a Tolland County quarry.

The cracking has taken 10-to-30 years to appear and the result has been a bill to homeowners that can reach $150,000, state officials have said, because repairs involving lifting the house, removing the old foundation, replacing the foundation, and securing the home to the new foundation.

When the rock was removed from the local quarry, it was not tested for pyrrhotite since the problem was not known at that time, Wille said.

The UConn engineering team is now working on five areas of focus:

• Developing an efficient and reliable sampling and testing method to determine the amount of pyrrhotite in the concrete foundations
• Establishing a field-testing program to support homeowners in getting their foundation tested for no additional cost
• Developing methods for accelerated testing in the lab to better understand how pyrrhotite will affect concrete in a shorter time span
• Creating a risk assessment framework for homeowners to support decision making
• Determine the effectiveness of potential mitigation strategies to prolong the concrete degradation process

The team plans to analyze more than 450 samples taken from homes with pyrrhotite detected in their foundations.

The results should help predict the probability of if — and when — a home’s foundation will be failing, UConn officials said.

See more about the UConn team's efforts on UConn Today.