EFFECTS OF AIR ENTRAINMENT ON PORTLAND CEMENT CONCRETE. INTERIM REPORT

Experience in Texas suggests problems may occur in stabilizing the air content of entrained concrete during and after pumping operations. In one instance, normal air entraining dosage rates were significantly exceeded in an effort to maintain the desired amount of air content in the concrete immediately after discharge. It was determined subsequently from hardened samples that the loss air was fully recovered and actually was 50% greater than the desired levels. Several factors have been noted in the literature to affect the level of entrained air in concrete. Factors such as cement content and fineness, coarse aggregate size, amount of fine aggregate, slump, type of admixture, etc., have been identified as factors affecting entrained air content. Preliminary test results indicate an apparent loss of air occurs immediately after discharge from the pump and tends to return after a period of time. This noted variation of air follows a dissolution process suggesting a shifting of the air-void system from smaller bubbles to larger bubbles. A test program is suggested to identify significant factors in this process.

• Supplemental Notes:
  • Research study title: Variations of Entrained Air Content of Pumped Concrete.
• Corporate Authors:

  Texas Transportation Institute

  Texas A&M University System, 1600 E Lamar Boulevard
  Arlington, TX  United States  76011

  Texas Department of Transportation

  Transportation Planning Division, P.O. Box 5051
  Austin, TX  United States  78763

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Chitla, S R
  • Zollinger, D G
  • Macha, R K
• Publication Date: 1991-12

Language

• English

Media Info

• Features: Figures; Photos; References; Tables;
• Pagination: 91 p.

Subject/Index Terms

• TRT Terms: Admixtures; Aggregates; Air entrainment; Cement content; Coarse aggregates; Fine aggregates; Fineness; Freeze thaw durability; Portland cement concrete; Pumps; Slump test
• Uncontrolled Terms: Aggregate size
• Subject Areas: Geotechnology; Highways; Materials; I32: Concrete;

Filing Info

• Accession Number: 00625282
• Record Type: Publication
• Report/Paper Numbers: FHWA/TX-92/1254-1, Res Rept 1254-1, TTI: 2-5-91-1254
• Contract Numbers: Study 2-5-91-1254
• Files: TRIS, USDOT, STATEDOT
• Created Date: Nov 4 1996 12:00AM