AIR CONTENT OF PLASTIC AND HARDENED CONCRETE

A combined field and laboratory testing program was conducted to compare air content in plastic and hardened concrete and to study the relationship of air content to vibration and compressive strength. Twelve plain concrete slabs were placed under normal field conditions. The slabs represented three levels of air content, two levels of vibration, and two types of coarse aggregate. Both the plastic and hardened concrete was subjected to a number of different tests. Air meter (Acme type) tests performed by different operators on the same batch of plastic concrete have a 95% probability of being within 0.80% of the mean. Analysis of variance of linear traverse data revealed that test also has good precision, as long as the air content does not exceed 7%. There is essentially no change in the entrained air content between plastic and hardened concrete. However, vibration does very significantly reduce entrapped air. Results of freeze/thaw tests reaffirm the value of entrained air voids in cement paste in preventing frost damage to concrete.

Media Info

  • Pagination: 73 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00091346
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: PDT-73-1 Final Rpt.
  • Files: NTIS, TRIS, USDOT, STATEDOT
  • Created Date: Jul 15 1975 12:00AM