Slag cement, or ground granulated blast furnace slag (GGBFS), has been incorporated into concrete projects in the U.S. for over a century to improve durability and reduce life cycle costs. Among its measurable benefits in concrete are better workability and finishability, higher compressive and flexural strengths, and improved resistance to aggressive chemicals.

Slag cement is a hydraulic cement. Used in proper proportions (usually from 20% to 80% of the cementitious material in a mixture depending on application), it adds strength and durability to concrete. Slag cement also improves concrete's plastic properties, such as workability and finishability. From an environmental perspective, its use in concrete only makes concrete “greener”: not only is it a recycled material, but, for each cubic yard of concrete in which it replaces portland cement, slag cement significantly reduces energy consumption and greenhouse gases emitted in the production of concrete raw materials.

Slag cement is produced in a tightly controlled process that ensures consistent chemical and physical properties. In fact, slag cement is one of the most consistent cementitious materials used in concrete. Industry specifications — such as ASTM C989, for slag cement, and ASTM C595 and C1157, for blended cements — ensure that specifiers receive a consistent product.