Stabilization of sulfate-contaminated crushed concrete base with type V cement and fly ash

The sulfate-contaminated crushed concrete base of a parking lot began to experience severe heaving because of the formation of secondary, expansive minerals (ettringite and thaumasite). Tests were performed in the laboratory to study the possibility of limiting the mobility of soluble sulfate ions by adding either a sulfate-resistant (Type V) cement or a combination of Type V cement and fly ash. The use of cement did not only prove practical because of the high moisture content of the base, but a mixture of 10 percent Type V cement and 9 percent Class C fly ash by weight yielded promising results for drying and encapsulating the free sulfate ions and providing a reasonably strong base.

Stabilization of sulfate-contaminated crushed concrete base with type V cement and fly ash Academic Article