Performance of Metakaolin and Portland Cements in Ettringite Formation as Determined by ASTM C 452-68: Kinetic and Morphological Differences

The ASTM C 452-68 test has been used as an accelerated method for predicting the potential behavior of ordinary Portland cement (OPC) under gypsum attack, but has not been used for the behavior of Portland cement blended with pozzolans and/or blast furnace slags. This article reports on a study in which the ASTM C 452-68 test was used to reveal certain differences between the ettringite formed from the reactive alumina present in pozzolans and the ettringite deriving from the C3A present in OPCs. The testing was conducted for 2 years on 40 cements, 10 Portland cements-6 OPCs and 4 SRPCs-and 30 blended cements containing 20%, 30% and 40% metakaolin (M pozzolan). ASTM C 452-68 specimens were manufactured with all cements and their daily length growth rate was calculated. Results show that the formation rate of the ettringite deriving from the reactive alumina present in pozzolans is considerably higher than the rate for ettringite forming from the C3A present in OPC.

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  • Accession Number: 01002062
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 19 2005 7:48AM