REALISTIC STRENGTH OF AIR-ENTRAINED CONCRETES WITH AND WITHOUT FLY ASH

Effects of various curing regimes on the strength development of both plain and fly ash concretes were studied. Three grades of air-entrained concretes with 28 day nominal strengths of 20, 30, and 40 MPa (2900, 4350, and 5800 psi) were cast. For each grade, 0, 20, 35, and 50 percent of the weight of cement was replaced by two subbituminous fly ashes. Cylinders were cured at 100 and 50 percent relative humidities and under outdoor ambient conditions--including a Canadian winter climate. Structural-size members were also exposed to the elements and strength was estimated by testing extracted cores. Results indicate exposure of test cylinders to site conditions does not adequately reflect strength development of the in situ concrete; this is particularly true if test cylinders are allowed to dry. Prediction of in situ strength from site-cured cylinders is particularly inaccurate for the fly ash concrete. For in situ concretes with a low total cementitious centent, the inclusion of fly ash in appreciable quantities is likely to result in slower strength gain than plain concrete. However, for higher grade concretes (higher total cementitious content) even with high ash content, early exposure to the elements is no more detrimental than it is to plain concrete.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/0889325X
• Corporate Authors:

  American Concrete Institute

  P.O. Box 19150, Redford Station, 22400 Seven Mile Road
  Detroit, MI  United States  48219
• Authors:
  • Haque, M N
  • Day, R L
  • LANGAN, B W
• Publication Date: 1988-7

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 241-247
• Serial:
  • American Concrete Institute, Journal of
  • Volume: 85
  • Issue Number: 4
  • Publisher: American Concrete Institute
  • ISSN: 0889-325X

Subject/Index Terms

• TRT Terms: Air entrained concrete; Cement content; Concrete; Fly ash; Forecasting; Strength of materials
• Uncontrolled Terms: Concrete strength
• Subject Areas: Geotechnology; Highways; Materials; I32: Concrete;

Filing Info

• Accession Number: 00475580
• Record Type: Publication
• Files: TRIS
• Created Date: Aug 31 1988 12:00AM