Ettringite
When sulfate is generated, it reacts with the alkaline substance calcium hydroxide in the concrete and forms calcium sulfate. The calcium sulfate reacts with a type of tricalcium aluminate that is a product of cement, and a chemical substance is generated called ettringite that absorbs large quantities of bonding water. The disintegration of concrete rapidly progresses through the formation of ettringite and its expansive swelling with bonding water. For this reason, it is important to have countermeasures in place.