Recycled cement raw material and recycled cement composition using the same

摘要

PROBLEM TO BE SOLVED: To provide: a regenerated cement raw material useful as a raw material for a regenerated cement composition obtained from a cement hardened body; a regenerated cement composition using the material and reducing carbon dioxide generated during production; and a mixed cement composition including the regenerated cement composition, reducing carbon dioxide generated during production, and having high flexibility.SOLUTION: The regenerated cement raw material is regenerated fine powder generated after separation and recovery of a filler material from the cement hardened body, containing CaO and SiOwith a mass ratio (CaO/SiO) of 0.6-3.0, and having an accumulated 50% particle diameter of 10 m or less and an accumulated 90% particle diameter of 20 m or less. The regenerated cement composition is made by grinding a sintered body obtained by calcining a mixture containing at least one selected from the group consisting of the (A) regenerated cement raw material, a (B) calcium raw material, an aluminum raw material and an iron raw material at a temperature of 1,300-1,500°C.