What is Slag Cement?
SCIC #1 – Slag Cement 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. SCIC #1, Slag Cement, provides an introduction to the material’s benefits, manufacturing process, and relevant terminology, and makes an excellent primer for those new to the cement and concrete industry.
Slag cement is a byproduct of an iron blast furnace, part of an integrated steel mill. When molten slag is separated from iron in a blast furnace, it can be rapidly quenched with water (“granulated”), dried and ground to a fine powder. At this point it becomes slag cement (or ground granulated blast furnace slag). Learn more…
Slag cement (also called ground granulated blast furnace slag) is a hydraulic cement produced during the reduction of iron ore to iron in a blast furnace. Molten slag is tapped from a blast furnace, rapidly quenched with water (“granulated”), dried and ground to a fine powder. The rapid quenching “freezes” the molten slag in a glassy state, which gives the product its cementitious properties. Q: What is slag cement used for? A: Slag cement is most widely used in concrete, either as a separate cementitious component or as part of a blended cement. It works synergistically with portland cement to increase strength, reduce permeability, improve resistance to chemical attack, and inhibit rebar corrosion. Slag cement is used in virtually all concrete applications. Slag cement is also used in non-concrete applications such as soil-cement and hazardous waste solidification. Q: Does slag cement change the hardened properties of concrete? A: Slag cement improves many of the strength and durabil
” Slag Cement; Slag Cement Association, Sugar Land, Texas; Available online at: http://www.slagcement.org Spoo, J. and P. Elsner; “Cement burns: a review 1960-2000”; Contact Dermatitis, 45(2), pp. 68-71, August 2001. Stern, A.H., Bagdon, R.E., Hazen, R.E., Marzulli, F.N., 1993; “Risk assessment of the allergic dermatitis potential of environmental exposure to hexavalent chromium”; Journal of Toxicology and Environmental Health, 40(4), pp. 613-641, 1993. Vickers, H.R., and Edwards, D.H.; “Cement burns”; Contact Dermatitis, 2, pp. 73-78, 1976. Zachariae, C.O.C., Agner, T., and Menne, T.; “Chromium allergy in consecutive patients in a country where ferrous sulfate has been added to cement since 1981”; Contact Dermatitis, 35, pp. 83-85, 1996; Munksgaard, Denmark.
Slag cement, often called ground granulated blast-furnace slag (GGBFS), is one of the most consistent cementitious materials used in concrete. Slag cement is actually a byproduct of iron production. When the iron is processed using a blast furnace, slag and iron both collect at the bottom of the furnace. The molten slag must first be separated from the molten iron. The molten slag is then diverted to a granulator where it undergoes granulation. Granulation is the process where the molten slag is rapidly drenched with water until it turns into a raw material called granules. The granules are then cooled rapidly, which stops crystals from forming and instead creates a glassy, non-metallic product. These granules are then dried and ground to a suitable fineness, the result of which is slag cement.
