| 摘要 |
<p>The present invention provides methods and compounds for the direct sequestration of chloride ions without requiring the addition of a source of anion such as nitrite or nitrate. A direct sequestration additive is introduced to fresh concrete or hardened concrete where the additive reacts with incoming chloride ions to form a low solubility, chloride-containing compound which captures or sequesters chloride ions. In a preferred embodiment, the chloride-containing compound comprises 3CaO.Fe<SUB>(2-x)</SUB>Al<SUB>x</SUB>O<SUB>3</SUB>.CaCl<SUB>2</SUB>.nH<SUB>2</SUB>O, where x ranges from about 0 to 1.4, and n ranges from about 8 to 24. The chloride ions may be provided in the form of deicing salt or sea water. Because chloride-containing compounds such as 3CaO.Fe<SUB>(2-x)</SUB>Al<SUB>x</SUB>O<SUB>3</SUB>.CaCl<SUB>2</SUB>.nH<SUB>2</SUB>O are formed directly without requiring the addition of a source of anion (e.g. nitrite or nitrate), the process is referred to as "direct sequestration."</p> |
