Effects of cement parameters on expansion associated with DEF

Title: Effects of cement parameters on expansion associated with DEF
Author(s): S. Kelham
Paper category : conference
Book title: International RILEM Workshop on Internal Sulfate Attack and Delayed Ettringite Formation
Editor(s): K. Scrivener and J. Skalny
Print-ISBN: 2-912143-44-6
e-ISBN: 2912143802
Publisher: RILEM Publications SARL
Publication year: 2004
Pages: 197 - 211
Total Pages: 15
Nb references: 2
Language: English

Abstract: A wide range of normal production and laboratory prepared cements have been used to study the volume stability of mortars. In addition to controls maintained at 20°C, prisms were subjected to high temperature curing regimes, typically 12 hours at 70, 80 or 90°C. Prism samples have been monitored for periods up to 10 years. Curing temperature was found to be the dominant factor in determining whether significant (>0.1%) expansion took place during subsequent water storage at 20°C. Most of the mortars expanded after curing at 90°C but few at 80°C and none at 70°C.Previous analyses of results for mortars cured at 90°C indicated that expansion increases with cement fineness, shows a maximum at a cement SO3 content of ~4% and that the pessimum SO3 content increases with alkali content. Positive correlations between expansion and C3S, C3A, MgO and alkali contents was also noted. However, while a number of parameters that can influence the expansion have been identified, no useful expression for the prediction of expansion after curing at a specified temperature has been found. The clearest correlation is with alkali content. All the mortars that expanded after curing at 80°C contained cements with high (>0.8%) alkali levels. Cement replacement levels of 30% or 40% with siliceous fly ash, and of 30% or 50% with ground granulated blastfurnace slag appear to prevent expansion.

Online publication: 2002-09-07
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2912143802.014

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