What are the green ‘mould-like’ markings on the floor? Will these markings go away?

Green markings on cement floors are as a result of slag cement (which is a by- product in the manufacturing of iron-ore) rising to the surface. Not only does the making of slag cement lessen the burden on landfills, but it also reduces air emissions at steel plants through the granulation process. It works synergistically with Portland cement to increase strength, reduce permeability, improve resistance to chemical attack and inhibit rebar corrosion. The bluish- green markings fade over time and are no cause for concern.

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