Title:
Effect of Metakaolin on External Sulfate Attack
Author(s):
T. Ramlochan and M. Thomas
Publication:
Symposium Paper
Volume:
192
Issue:
Appears on pages(s):
239-252
Keywords:
blended cements; ettringite; gypsum; pozzolans; sulfate attack
DOI:
10.14359/5752
Date:
4/1/2000
Abstract:
This paper reports a study on the effect of a high-reactivity meakaolin (HRM) on the sulphate resistance of mortars. Mortar bars containing 0-25% HRM were prepared in accordance with ASTM C 1012-89 with three cements of varying C3A content. After 6 months of exposure to a 5% Na2SO4 Solution, mortar bars incorporating any level of HRM (5-25%) as a partial replacement for a high-C3A cement (~10%C3A) may be considered "moderate sulphate resistant"; mortar bars made with HRM and a moderate or low-C3A cement (<6% C3A) may be considered "high-sulphate resistant". Beyond 6 months, however, it was found that insufficient levels of HRM may, in fact, reduce the sulphate resistance of some cements, and that 15% HRM, or more, may be required for long term sulphate resistance, depending on the C3A content of the cement.