Patent ID: 8076396

Claim:
A method of using an ultrarapid hardening cement composition wherein the method comprises a step of kneading and placing the ultrarapid hardening cement composition at an ambient temperature of 15° C. or less, wherein the ultrarapid cement hardening composition comprises: an ultrarapid hardening cement (A) comprising a calcium aluminate; and a cement dispersant (B), wherein the cement dispersant (B) comprises a copolymer having: a repeating unit derived from a monomer represented by the following formula (1): in the formula, R 1 being the same or different and each representing a hydrogen atom or an alkyl group containing 1 to 18 carbon atoms; n representing an average molar number of addition and being a number of 10 to 300; and a repeating unit derived from a monomer represented by the following formula (2): in the formula, M representing a hydrogen atom, a monovalent metal atom, a divalent metal atom, an ammonium group, or an organic amine group; wherein the ultrarapid hardening cement composition is produced by being kneaded at a water/the ultrarapid hardening cement (A) ratio of 35% by mass or less and wherein the mass ratio of the cement dispersant (B) to the ultrarapid hardening cement (A) is 0.01:100 to 8.0:100.