Slag Cement in Concrete and Mortar

Description

The use of ground granulated iron blast-furnace slagcement (slag cement) as a cementitious material dates backto 1774 when Loriot made a mortar using slag cement incombination with slaked lime (Mather 1957).

In 1862, Emil Langen proposed a granulation process tofacilitate removal and handling of iron blast-furnace slagleaving the blast furnace. Glassy iron blast-furnace slagswere later investigated by Michaelis, Prussing, Tetmayer,Prost, Feret, and Green. Their investigations, along with thatof Pasow, who introduced the process of air granulation,played an important part in the development of iron blast-furnace slag as a hydraulic binder (Thomas 1979). Thisdevelopment resulted in the first commercial use of slag-lime cements in Germany in 1865. In France, these slagcements were used as early as 1889 to build the Paris under-ground metro system (Thomas 1979).

Mary (1951) described the preparation of slag cement bythe Trief wet-process and its use in the Bort-les-OrguesDam. This was done after World War II when the supply ofportland cement was limited. The dam involved 660,000 m3(863,000 yd3) of concrete. The slag was ground wet andcharged into the mixer as a thick slurry.

A sample of the Trief wet-process cement was obtained bythe Corps of Engineers in December 1950 and tested at theWaterways Experiment Station (WES) (Waterways Experi-ment Station 1953). In the WES tests, the behavior of theground slag from Europe was compared with slag ground inthe laboratory from expanded slag from Birmingham, Ala.Each slag was activated with 1.5% sodium hydroxide and1.5% sodium chloride by mass, with generally similar results.In the former Soviet Union and several European countries,the use of slag cement in alkali-activated systems where noportland cement is used has been found to provide specialproperties (Talling and Brandstetr 1989).

The first recorded production of blended cement in whichblast-furnace slag was combined with portland cement was inGermany in 1892; the first United States production was in1896. By 1980, the use of slag cement in the production ofblended cement accounted for nearly 20% of the total hydrauliccement produced in Europe (Hogan and Meusel 1981).