EFFECTS OF PULVERISED FUEL ASH ON ALKALI-SILICA REACTION IN CONCRETE
The partial replacement of Portland cement (PC) by pulverised fuel ash (PFA) in a series of potentially reactive concretes significantly reduced expansion due to alkali-silica reaction (ASR) in high alkali mixes, whereas, in marginally reactive concretes with loweer alkali levels, 25% addition of a high alkali PFA slightly increased the expansion compared with that developed by the equivalent PC mix. This extra expansion, however, was insignificant in terms of the likelihood of causing physical damage. Pore solution analysis indicated a continuing slow release of potassium ions from the PFA but the observed relationships between ASR expansion and pore solution composition of the various concretes studied were somewhat unclear. Petrographic analysis suggested that although no significant expansion-induced microcracking was observed in the cement matrix of PFA concretes, the degree of internal microcracking and gel formation in the reactive aggregate particles was very similar to that seen in the equivalent mixes containing no PFA. This suggests that physical changes to the cement matrix as well as variations in the pore solution alkalinity affect the degree of ASR expansion developed by concretes containing PFA. (A)
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Availability:
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Corporate Authors:
The Boulevard, Langford Lane
Kidlington, Oxford United Kingdom OX5 1GB -
Authors:
- SIBBICK, R G
- Page, C L
- Publication Date: 1995
Language
- English
Media Info
- Features: References;
- Pagination: p. 289-93
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Serial:
- Construction and Building Materials
- Volume: 9
- Issue Number: 5
- Publisher: Elsevier
- ISSN: 0950-0618
- Serial URL: http://www.sciencedirect.com/science/journal/09500618?sdc=1
Subject/Index Terms
- TRT Terms: Alkali; Chemical reactions; Concrete; Fly ash; Mix design; Oxides; Silicon
- ITRD Terms: 7353: Alkali; 4755: Concrete; 4580: Fly ash; 4714: Mix design; 7372: Oxide; 7156: Reaction (chem); 7148: Silicon
- Subject Areas: Design;
Filing Info
- Accession Number: 00720849
- Record Type: Publication
- Source Agency: Transport Research Laboratory
- Files: ITRD
- Created Date: May 24 1996 12:00AM