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Journal of the Korea Concrete Institute

J Korea Inst. Struct. Maint. Insp.
  • Indexed by
  • Korea Citation Index (KCI)
Title Binding of the Hexavalent Chromium Ions in the Process of Cement Hydration
Authors 정민선 ; 황준필 ; 홍성인 ; 안기용
Page pp.88-94
ISSN 2234-6937
Keywords 6가 크롬 (Cr(VI)) ; 시멘트 ; pH ; 분광광도법 ; 고정화 ; 수화 ; Hexavalent chromium (Cr(VI)) ; Cement ; pH ; Spectrophotometer ; Binding ; Hydration
Abstract The hexavalent chromium (Cr(VI)) is well known as a hazardous ion, presumably inducing dermatic diseases and if serious cancer. The present study concerns the binding capacity of Cr(VI) ions in the cement powder and matrix for a quantitative technique of Cr(VI) ions in cement to influence human health. Both the water-soluble and acid-soluble Cr(VI) ions present in 3 types of ordinary Portland cement (OPC), pulverised fuel ash (PFA), ground granulated blast furnace slag (GGBS), and silica fume (SF) were measured using the spectrophotometer. As a result, it was found that the concentration of water-soluble Cr(VI) ion in cement ranged from 10.5 to 18.9mg/kg-cement, and in the additional materials a very low value of Cr(VI) ion was measured. Acid-soluble Cr(VI) ion was even higher than water-soluble Cr(VI) ion, ranging from 172.4 to 318.2mg/kg-cement. Nevertheless, the concentration of acid-soluble Cr(VI) ion is not proportional to addition of acid. It depends rather the variable pH of solvent involving cement paste. As enough cement hydration occurs, the binding capacity of Cr(VI) ion increases, inhibiting this ions from leaching out in the presence of hydration products such as ettringite or tri-calcium aluminate which bind Cr(VI) ion by ion-exchange.