Drying shrinkage-reducing agent

Abstract

A drying shrinkage-reducing agent which comprises a polymer containing as an essential component at least one structural unit (I) represented by the following formula (1): wherein R1, R2, and R3 independently stand for a hydrogen atom, a methyl group, or a —(CH2)pCOOX group, wherein X stands for a hydrogen atom, a monovalent metal, a divalent metal, an ammonium group, an organic amine group, or a hydrocarbon group, and p is an integer of 0-2; and R4 stands for a hydrocarbon group of 4-30 carbon atoms, and exhibiting surface tension in the range of 25-50 mN/m in a solution containing 0.2 mass % of the polymer in a cement supernatant is provided. The drying shrinkage-reducing agent manifests no dispersibility in an amount capable of attaining necessary drying shrinking-reducing properties and, when used in combination with a dispersing agent, acquires ability to adjust the dispersibility and the drying shrinkage-reducing properties fit for the purpose.

Dependencies are inferred from the claim text.