Freeze-Thaw and De-Icing Salt Resistance of Concrete Containing Mineral Admixtures and Air-Entraining Agent

Abstract

The effect of mineral admixtures and air-entraining agent on freezing-thawing and de-icing salt resistance of concrete has been studied. Concrete specimens made with ordinary Portland cement or ordinary Portland cement incorporating fly ash with the replacement of 10% or 20%, or 0.7/10000 air-entraining agent and fly ash with the replacement of 20%, or ground blast furnace slag with the replacement of 15% or 30%, were made and exposed to 500 cycles of freeze-thaw and de-icing salt environment. Concrete properties including loss of mass, relative dynamic elastic modulus, compressive strength, flexural strength and chloride ion diffusion coefficient were measured. Phase composition of samples was determined by means of x-ray diffraction (XRD). Results indicate that concrete exposed to freeze-thaw and de-icing salt environment is subjected to both physical frost action and chemical corrosion. Incorporation of mineral admixtures and air-entraining agent possesses more effect on internal deterioration, mechanical properties and permeability of concrete than on the scaling of concrete.