Air Void Analyzer (AVA)

Premature deterioration of cement-based concrete structures puts a tremendous financial burden on many transportation agencies. Moreover, badly deteriorated concrete in pavements, bridges, and other highway structures adversely affects economic productivity by increasing the number of work zones while indirectly placing motorists at risk. In much of the United States, concrete deteriorates as a result of repeated freezing and thawing. Damage often is exacerbated by multiple applications of deicing salts, which accelerate cracking, deterioration, and surface scaling. Concrete life can be increased by improving its ability to endure repeated freeze-thaw cycles over its expected design life. The presence of closely spaced air voids in concrete is commonly singled out as the primary factor in improving the freeze-thaw resistance of concrete. Researchers believe that as water expands during freezing, the pressure the water develops increases in relation to the distance it must travel to reach the nearest air void. Consequently, the more closely air voids in concrete are spaced, the less likely it is that the pressure of freezing water will damage the concrete. The air void analyzer (AVA) offers an efficient, real-time method for assessing the distribution of air voids in fresh concrete. The device can characterize the distribution of air voids in less than 30 minutes. With this information, adjustments can be made in the concrete batching process to ensure that air voids are spaced properly.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Pagination: 2p

Subject/Index Terms

Filing Info

  • Accession Number: 01153192
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-HRT-06-057, HRTC-01/01-06(1M)E
  • Files: NTL, TRIS, USDOT
  • Created Date: Mar 23 2010 11:54AM