In this cement type up to 35% of "
Burnt Shale" can be used in cement to substitute clinker.
Township roads then were mostly covered with "red dog," the
burnt shale that is left when the pile of discarded stone and coal from a mine tipple goes through spontaneous combustion.
Describing her work on the "terrible beauty" of Durham's coastline, Konttinen wrote: "Coal-black sand frosted with sulphur, purple rocks of
burnt shale, pebbles luminous with iron dioxide.
However, demolition and site clearance identified potential problems in the form of
burnt shale and unfavourable geology.
Kunda Nordic Cement in Kunda, Estonia, and Holcim Dotternhausen cement plant are using
burnt shale as a cement component.
Kikas and coworkers, studying the influence of OSA on the properties of self-stressing shale ash cement, concluded that the concrete made with
burnt shale is characterized by high strength, high frost resistance, and low permeability.
Research on Estonian oil shale ash has shown that the use of
burnt shale as a feedstock in production of cement is very effective.
In Dotternhausen, Germany, for example, clinker (raw meal and oil shale) from the rotary kiln and hydraulic
burnt shale from fluidised bed combustion unit together are used to produce Portland-burnt shale cement [3].
That means that the
burnt shale, when mixed with water, gets hard and develops strength like cement.