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AssigneeDenki Kagaku Kogyo Kabushiki Kaisha
InventorsMinoru Morioka, Takayuki Higuchi, Hiroyuki Ohashi, Yasuhiro Nakashima
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A cement admixture and a cement composition having a carbonation suppressing effect and a heat-of-hydration suppressing effect are provided. A cement admixture containing one or more non-hydraulic compounds selected from the group consisting of γ-2CaO.SiO2, α-CaO.SiO2 and calcium magnesium silicate, a cement composition containing said admixture, and a carbonation suppressing method by use of said cement admixture or cement composition. According to the present invention, a remarkable carbonation suppressing effect can be obtained particularly when used in portland blast-furnace slag cement. This leads to an effective use of steelmaking slag and the like, and the load of clinker can be reduced, so that a cement composition of a low environmental load type can be attained. Further, this is suitable for cements in conformity with the EN standards, which are used in civil engineering and building industries.
A cement composition comprising a cement settable by hydration and subject to carbonation and a cement admixture which is a non-hydraulic material comprising the compound γ-2CaO·SiO2 as a main component, the total content of γ-2CaO·SiO2 in the non-hydraulic admixture material being 65% or more, the content of 12CaO·7Al2O3 and/or 11CaO·7Al2O3·CaF2 being 25% or less, the total content of fluorine being 2% or less, and the content of the cement admixture being 5-50 parts in 100 parts of the total of the cement and the cement admixture.
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