PROBLEM TO BE SOLVED: To provide a quicklime-based expansive admixture that can sufficiently suppress shrinkage during hardening and can prevent the occurrence of cracking without mixing it in such a large amount as to give any troubles to the properties of a hardened body in a cement composition such as mortar and concrete.SOLUTION: The expansive admixture comprises as an active ingredient a mixture of a quicklime-containing particle having a particle size of not less than 20 μm which is substantially coated with diethylene glycol and a quicklime-containing particle having a particle size of less than 20 μm which is substantially coated with diethylene glycol having a mass 3 to 20 times as much as that of diethylene glycol used in coating the mentioned-above particle.SELECTED DRAWING: None
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