AIR VOID STABILITY, PART IV: RETEMPERING
Eight laboratory mixes and eight field mixes were prepared to study the influence of retempering by adding water to the characteristics of the air-void system, and to study air entrainment when an air-entraining admixture is added significantly after the initial mixing period. For each mix, four sets of samples were cast over a period of 90 min after initial water-cement contact: two before retempering (at 45 min) and two after. The modified point-count method (ASTM C 457) was used to determine the characteristics of the air-void spacing factor, although it often causes a small increase in air content. The results also show that it is possible to entrain an adequate air-void system with a spacing factor of less than 200 mu m if a normal dosage of the air-entraining agent, with a little water, is incorported into the mix 45 min after the initial water-cement contact. An unsatisfactory air-void system can be corrected by adding more of the air-entraining agent after 45 min, but the quantity added must be great enough (i.e., more than 30 to 50 % of the normal dosage) to significanly lower the value of the spacing factor. The results further show that small air-content variations (lower than 2 %) should not be used to predict spacing factor variations.
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/oclc/13846872
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Corporate Authors:
P.O. Box 19150, Redford Station, 22400 Seven Mile Road
Detroit, MI United States 48219 -
Authors:
- Pigeon, M
- SAUCIER, F
- Plante, P
- Publication Date: 1990-5
Media Info
- Features: Appendices; Figures; References; Tables;
- Pagination: p. 252-259
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Serial:
- ACI Materials Journal
- Volume: 87
- Issue Number: 3
- Publisher: American Concrete Institute (ACI)
- ISSN: 0889-325X
- Serial URL: https://www.concrete.org/publications/acimaterialsjournal.aspx
Subject/Index Terms
- TRT Terms: Air entrained concrete; Air entraining agents; Air entrainment; Air voids; Slump test; Stability (Mechanics); Water
- Old TRIS Terms: Air voids content; Retempering, concrete
- Subject Areas: Highways; Materials; I32: Concrete;
Filing Info
- Accession Number: 00495272
- Record Type: Publication
- Report/Paper Numbers: Title No. 87-M28
- Files: TRIS
- Created Date: Jul 31 1990 12:00AM