Cement admixture and their use in chemically prestressed concrete

摘要

The invention relates to a cement additive comprising amorphous calcium aluminate and an expansive material prepared by subjecting a mixture of CaO raw material and CaSO4 raw material to heat treatment, where the content of CaSO4 in the expansive material formed is from 20 to 50 parts by weight in 100 parts by weight of the total amount of CaO and CaSO4.