2010 Volume 64 Issue 1 Pages 428-434
When CaO・2Al2O3 was mixed to ordinary portland cement, 3CaO・Al2O3・Ca（OH）2・12H2O has formed a large amount of in hardened cement by the reaction of CaO・2Al2O3 and Portlandite. Amount of portlandite was formed in hardened cement has decreased with increased of amount of CaO・2Al2O3, because 3CaO・Al2O3・Ca（OH）2・12H2O formed a large amount of in hardened cement by the reaction of CaO・2Al2O3 and Portlandite. Amount of leaching of Portlandite in hardened cement added with CaO・2Al2O3 into NaCl solution has decreased with increased of amount of CaO・2Al2O3. When CaO・2Al2O3 was mixed to ordinary portland cement, Penetration of chloride ion into hardened cement was decelerated compared with hardened ordinary portland cement because formation of Friedel’s salt for the reaction of 3CaO・Al2O3・Ca（OH）2・12H2O and chloride ion. When CaO・2Al2O3 was mixed to ordinary portland cement, amount of fixed chloride ion has increased and ratio of soluble chloride ion in total chloride ion has decreased in hardened cement. This reasons was chemical effect of fixation of chloride ion by formation of Friedel’s salt for the reaction of 3CaO・Al2O3・Ca（OH）2・12H2O and chloride ion.
