Why Slag Cement?
The use of slag cement has demonstrated long-term performance enhancements allowing designers to reduce the environmental footprint of concrete while ensuring improved performance and increased durability.
The benefits of using slag cement include:
Easier placeability and finishability
Higher long-term compressive and flexural strengths
ASR mitigation properties
Improved durability and resilience
More consistent performance
What is Slag Cement?
Slag cement is a hydraulic cement formed when granulated blast furnace slag (GGBFS) is ground to suitable fineness and is used to replace a portion of portland cement. It is a recovered industrial by-product of an iron blast furnace. Molten slag diverted from the iron blast furnace is rapidly chilled, producing glassy granules that yield desired reactive cementitious characteristics when ground into cement fineness. Once the slag has been cooled and ground to a usable fineness it is stored and shipped to suppliers throughout the United States. Slag cement is commonly found in ready-mixed concrete, precast concrete, masonry, soil cement and high temperature resistant building products.
Slag Cement's History
Slag cement use can be traced to the 1700s when the material was combined with lime to make mortars. The first United States production was in 1896.
Until the 1950s, granulated slag was used in the manufacture of blended portland cements, or as raw feedstock to make cement clinker. However, in the 1950s, slag cement became available in other countries as a separate product. The first granulation facility in the U.S. to make a separate slag cement product was Sparrows Point, Maryland, in the early 1980s.
Recent years have seen the supply and acceptance of slag cement grow dramatically throughout the U.S. The product is now widely available east of the Rockies.
This section contains answers to frequently asked questions (FAQ) about slag cement, and links to the Slag Cement in Concrete (SCIC) information sheet series that provides more detail. If you have questions that are not answered here, email SCA at email@example.com.