Title: Internal Sulfate Attack: Distress Mechanism at Ambient and Elevated Temperatures?
Author(s): W. Klemm and F. M. Miller
Publication: Symposium Paper
Appears on pages(s): 81-92
Keywords: ambient temperature; anhydrite; clinker; ettringite; silicate; sulfate
Recent debate on delayed ettringite formation (DEF) as a form of internal sulfate attack - a distress mechanism for ambient- and steam-cured concrete - has motivated this paper, which examines relevant data from the literature and from the authors’ laboratory. DEF can be associated with distress in high temperature concrete, but not for ambient-curing in the absence of external SO3 sources, or an aggregate sulfate source. The two internal SO3 sources cited as potentially responsible -anhydrite in clinker and high SO3 concentrations in the silicate phases -are shown to be absent or fundamentally innocuous.