Influence of Air Content on Frost Damage Resistance of Moderate-Heat Portland Cement Concrete with Fly Ash in Setting Process

Abstract

This study focused on air-entraining capability and resulting freeze and thaw resistance in moderate-heat Portland cement concrete with fly ash (MHC-FA concrete) which is generally applied for dam construction. Experimental results demonstrated that entrained air tends significantly to decrease during fresh states with time in MHC-FA concrete, which leads to deteriorating freeze and thaw resistance. This phenomenon appears to be caused by bleeding, which destroys air bubbles in MHC-FA concrete more than in normal concrete. Therefore, MHC-FA concrete with higher bleeding amounts shows more remarkably decreasing air contents. As a result, the authors propose to initially introduce higher entraining air amount to maintain freeze and thaw resistance in MHC-FA concrete.