A REVIEW OF LIMESTONE ADDITIONS TO PORTLAND CEMENT AND CONCRETE

Abstract Whether or not to add limestone to Portland cement clinker and gypsum is currently being debated in many countries. Upon addition of the calcium carbonate a reaction occurs between it and the tricalcium aluminate that is present in the clinker to form calcium carboaluminates. Their ability to control set characteristics of the cement and their effects upon physical properties are discussed. It appears that in cements with higher levels of the tricalcium aluminate, positive or no effects on cement quality are noted. In cements with lower amounts of tricalcium aluminate, deleterious effects upon physical properties have been noted in some instances. It may be possible to control other properties of the cement to allow limestone additions even in cements with lower levels of tricalcium aluminate.