The influence of sulfate content in clinker or cement and curing temperature on DEF-related expansion of concrete

Title: The influence of sulfate content in clinker or cement and curing temperature on DEF-related expansion of concrete
Author(s): M. Collepardi, J. J. Ogoumagh Olagot
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: 212 - 228
Total Pages: 17
Nb references: 5
Language: English

Abstract: Cement pastes and concrete specimens were cured at 20°C or steam-cured up to 90°C. At curing temperature higher then 70°C, ettringite disappears and then forms again at later ages (DEF). Concretes manufactured at room temperature (20°C) do not show any form of DEF-related expansion independently of the SO3 content of the clinker (1-2%) or the portland cement (2-4%). On the other hand, concretes steam-cured at 90°C and then kept under water show significant expansion related to DEF provided that the SO3 content of the portland cement is relatively high (> 4%). The higher SO3 content in the clinker phases (> 2%) or the presence of pre-existing cracks exacerbate the DEF-related expansion. Deposition of ettringite fibre crystals occurs in the pre-existing cracks or within the new microcracks. However, no clear evidence was found between the ettringite deposition and the width-change of the cracks. Curing at temperatures lower than 70°C is strongly recommended to avoid DEF-related risk. Blended cements with a lower SO3 content should be used in case this limit in curing temperature cannot be safely ensured.

Online publication: 2002-09-07
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2912143802.015