Patent ID: 8519028

Claim:
An early strengthening agent for a hydraulic composition, comprising one or more compounds (A) selected from the group consisting of: a compound represented by the following general formula (A1): wherein R represents a hydrogen atom, a methyl group or an ethyl group, and Z represents —OH or —O—CH 2 CH 2 —OH, a compound represented by the following general formula (A2): wherein A 1 represents an alkylene group having 2 carbon atoms, m1, m2 and m3 each represent an integer indicating the number of moles of A 1 O added and the average of the sum in total of m1, m2 and m3 in the compound represented by the general formula (A2) is 0.5 to 2.5, the compound represented by the general formula (A2) comprises an adduct of 1 mole of ethylene oxide, an adduct of 2 moles of ethylene oxide, and an adduct of 3 moles of ethylene oxide in a total amount of 43% by weight of more, wherein an amount of the adduct of 1 mole of ethylene oxide is 15 to 100% by weight, and a compound represented by the following general formula (A3): wherein R's are the same as or different from one another and each represent a hydrogen atom or a group selected from the group consisting of a methyl group, an ethyl group and a propyl group, at least one of R's is group selected from the group consisting of a methyl group, an ethyl group and a propyl group; and A 2 represents an alkylene group having 2 carbon atoms, and m4 is a number of 0 to 2 that is the average number of moles of A 2 O added.