Formation and stability of 3CaO center dot CaCl2 center dot 12H(2)O

Formation of 3CaO . CaCl2. 12H(2)O, which is a very unstable complex salt, in deteriorated concrete attacked by calcium chloride has been regarded as a main cause for the deterioration of cement concrete. In this study, a slu rry from Ca(OH)(2)-CaCl2-H2O System was examined under different conditions . X-ray diffraction (XRD) analysis indicates that 3CaO-CaCl2. 12H(2)O canno t be detected in the original slurry, but is detected after acetone washing of the slurry. 3CaO . CaCl2. 12HO disappears when the acetone-washed sampl e is air-dried at 20 degreesC and 20% relative humidity. Thus, cautions sho uld be taken during the preparation of samples during the examination of ca lcium chloride attacked concrete. (C) 2001 Elsevier Science Ltd. All rights reserved.