What happens when sulfates get into concrete?
As the sulfate infiltrates concrete, it combines with the C-S-H, or concrete paste, and begins destroying the paste that holds the concrete together. As sulfate dries, new compounds are formed, often called ettringite. These new crystals occupy empty space, and as they continue to form, they cause the paste to crack, further damaging the concrete. The concrete weakens and the paste continues to separate and crack. Consequently, the concrete becomes increasingly permeable, allowing in more and more water filled with sulfates. Over time the process accelerates dramatically. The excess water content and porosity also begin to rust away the anchor bolts that tie the home’s structure to the foundation.
