Formation and stability of 3CaO•CaCl2•12H2O

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 slurry from Ca(OH)(2)-CaCl2-H2O System was examined under different conditions. X-ray diffraction (XRD) analysis indicates that 3CaO-CaCl2. 12H(2)O cannot be detected in the original slurry, but is detected after acetone washing of the slurry. 3CaO . CaCl2. 12HO disappears when the acetone-washed sample is air-dried at 20 degreesC and 20% relative humidity. Thus, cautions should be taken during the preparation of samples during the examination of calcium chloride attacked concrete. (C) 2001 Elsevier Science Ltd. All rights reserved.