Frost Durability of Concrete Containing Viscosity-Modifying Admixtures

Abstract

The use of viscosity-modifying admixtures in special concrete intended for underwater placement/repair and land-based applications has increased, yet limited information exists about the frost susceptibility of such concrete. The effect of an adding sequence of the air-entraining admixture, in relation to the viscosity-modifying admixture and the high-range water reducer on an air-void system, is evaluated. The impact of two commonly used viscosity-modifying admixtures, welan gum and hydroxypropyl methylcellulose, on frost durability and scaling resistance is determined for fluid mixes made with w/c ratios of 0.32, 0.40, and 0.45. Findings indicate that the air-entraining admixture is most effective when added after the viscosity-modifying admixture and high-range water reducer. Assuming that a sufficient air-void system is secured, concrete made with welan gum or hydroxypropyl methylcellulose can display adequate frost durability similar to that of conventional concrete.