AIR CONTENTS AND AIR-VOID CHARACTERISTICS IN LOW-SLUMP DENSE CONCRETES

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. 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 1 to 2 percent and could be reduced to below 1 percent if prolonged internal vibration was employed.