Influence of fine aggregate lithology on internal sulfate attack in high early strength concrete
Author(s): A. M. Amde, K. Williams, R. A. Livingston
Paper category: Workshop
Book title: RILEM International workshop on performance-based specification and control of concrete durability
Editor(s): D. Bjegović, H. Beushausen, M. Serdar
Pages: 599 - 605
Total Pages: 7
The influence of fine aggregates on internal sulfate attack in concrete is investigated using three different fine aggregates with different expansion test ratings and one limestone nonreactive coarse aggregate. The storage conditions for prism specimens included: under water, 100% RH and ambient conditions. A modified Duggan test method, SEM, EDAX, X-ray Computed Tomography and compressive strength were used to investigate internal sulfate attack as a possible damage mechanism.
The study concludes that fine aggregate type can significantly predispose a concrete sample to delayed ettringite formation and associated damaging expansion, while the exposure condition may exacerbate the effect. The kinetics of the expansion varied among the aggregates. It is important to examine the time derivative of expansion to characterize the process rather than measured expansions at some fixed point in time. This suggests that the effect of each type of aggregate on the microstructure and hence the absorptivity of the cement paste needs to be considered in addition to its potential for ASR in evaluating expansion test data.
Ettringite was observed in most of the specimens. The morphology of the crystals may be an indication of the progress of damage; expansions come from a combination of moisture absorption, DEF and ASR.
Online publication: 2013
Publication Type: full_text
Public price (Euros): 0.00