Air Contents and Air-Void Concretes
Characteristics in Low-Slump Dense
Appears on pages(s):
air-entrained concretes; air-entraining agents; air entrainment; air meters; fresh concretes; hardened concretes; resurfacing; voids.
Air-void systems of low slump, low water-cement ratio concretes (LSDC) used for "dense" concrete overlays were evaluated. Dosages of neutralized vinsol resin and alkyl-benzyl sulfonate-based air-entraining agents needed to achieve specified air contents were approximately ten times those used in conventional concrete mixtures. For two other types of agents (a tall-oil derivative and an alkali-stabilized wood resin), specified air contents could not be achieved even at dosage rates approaching S percent by weight of cement. Once the specified air contents had been achieved in the fresh concrete, air content and air-void characteristics in the hardened concrete were satisfactory. Entrapped air contents ranged from I to 2 percent and could be reduced to below 1 percent if prolonged internal vibration was employed.