Long-term thaumasite sulfate attack on Portland-limestone cement concrete: A multi-technique analytical approach for assessing phase assemblage

摘要: Abstract Multiple techniques were applied to the investigation of phase composition deteriorated surface Portland-limestone cement concrete specimens exposed for 10 years conditions promoting thaumasite sulfate attack. The results interpreted in terms limestone content and incorporation supplementary cementitious materials (SCMs) (natural pozzolana, blastfurnace slag, metakaolin). Thaumasite, detected high amounts made without SCMs, was associated with Al some extent. Considerable degradation calcium silicate hydrate occurred all specimens, resulting formation Al-associated cross-linked chains, magnesium silica gel, a process most effectively prevented by metakaolin. For highest or use natural underwent extensive decomposition. into chains increased increasing cement. Longer aluminosilicate larger fractions observed incorporating SCMs.