Cement additive and cement composition

(22) 22.02.2017

(43) 08.02.2018

(57) The purpose of the invention is to provide a cement additive and a cement composition which have excellent solution stability, achieve a good fluidity holding effect and an autogenous shrinkage reducing effect for cement concrete, and which exhibit immediate and sustained hexavalent chromium reduction. The present invention provides: a cement additive which is a mixture of a lime sulphur mixture having a pH of 10 or more and an oxidation-reduction potential (ORP) of -450 mV or less and one or more types of a liquid water reducing agent selected from naphthalenes, melamines, aminosulfonic acids, polycarboxylic acids, or polyethers; the abovementioned cement additive wherein the liquid water reducing agent has a pH of 8 or more; the abovementioned cement additive wherein the lime sulphur mixture includes 5 to 15 % by mass of Ca in terms of T-Ca, 15 to 30 % by mass of S in terms of T-S, and 0.03 to 2.0 % by mass of Mg in terms of MgO; and a cement composition containing cement and the cement additive.

(71) Denka Company Ltd (JP)