INVESTIGATION OF VACUUM MIXING OF CONCRETE

CONCRETE MIXTURES FOR THIS STUDY WERE PROPORTIONED TO CONTAIN EITHER 3/4-IN. MAXIMUM-SIZE LIMESTONE OR 3/4-IN. LIGHTWEIGHT AGGREGATE, BOTH WITH AND WITHOUT ENTRAINED AIR. EACH MIXTURE WAS MIXED BOTH IN THE STANDARD MANNER AND UNDER REDUCED PRESSURE TO DETERMINE THE EFFECT OF VACUUM MIXING ON PROPERTIES OF CONCRETE. ADDITIONAL BATCHES OF THE CONCRETE MIXTURES CONTAINING LIMESTONE AGGREGATE WERE VACUUM-MIXED TO DETERMINE THE EFFECT OF THE ADDITION OF AMMONIA WATER, AND ALSO TO DETERMINE IF ADDITIONAL AIR COULD BE ENTRAINED BY REMIXING CONCRETE AT NORMAL PRESSURE THAT HAD BEEN PREVIOUSLY VACUUM-MIXED. THE RESULTS OF THE TESTS INDICATED THAT VACUUM MIXING DECREASED THE AIR CONTENT OF THE CONCRETE SOMEWHAT. VACUUM MIXING ALSO RESULTED IN A SLIGHT INCREASE IN THE STRENGTH OF THE MIXTURES CONTAINING ENTRAINED AIR AND A SLIGHT DECREASE IN THE STRENGTH OF MIXTURES NOT CONTAINING ENTRAINED AIR WITH EACH OF THE TWO AGGREGATES. THE REDUCTION IN AIR CONTENT RESULTED IN A CONSIDERABLE DECREASE IN THE RESISTANCE TO FREEZING AND THAWING OF THE AIR-ENTRAINED CONCRETE CONTAINING LIMESTONE AGGREGATES. RESULTS OF THIS LIMITED TESTING INDICATED THAT NO APPARENT ADVANTAGES ARE OBTAINED THROUGH USE OF VACUUM MIXING. /AUTHOR/

• Supplemental Notes:
  • No 6-938, 21 PP
• Authors:
  • Tynes, W O
• Publication Date: 1967-10

Media Info

• Serial:
  • Waterways Exp Sta Misc Papers

Subject/Index Terms

• TRT Terms: Ammonia; Concrete; Concrete mixing; Crash investigation; Entrained air; Freeze thaw durability; Lightweight aggregates; Limestone aggregates; Physical properties; Studies; Vacuum
• Uncontrolled Terms: Concrete properties
• Old TRIS Terms: Freezing thawing effects; Resistance
• Subject Areas: Highways; Materials; Safety and Human Factors;

Filing Info

• Accession Number: 00212541
• Record Type: Publication
• Files: TRIS
• Created Date: Jan 24 1994 12:00AM