Response of Concrete with Blended Binders and Nanosilica to Freezing–Thawing Cycles and Different Concentrations of Deicing Salts

Abstract

Concrete deterioration in cold climate regions is a great concern from a durability perspective because of deicing salts and freezing–thawing (F/T) cycles. This study investigates the response, in terms of physicomechanical properties and microstructural features, of concrete made with different types of cement—general use cement and portland limestone cement (PLC)—without or with fly ash and nanosilica to F/T cycles combined with different concentrations of chloride-based deicing salts (MgCl2 and CaCl2). The results reveal that the resistance of concrete exposed to deicing salts is a function of physical penetrability (magnitude of intruding chloride), amount of aluminate in the cement, and content of portlandite available for chemical reactions in the hydrated paste. PLC mixtures exhibit better resistance to deicing salts due to synergistic physical and chemical actions of limestone in the matrix. Fly ash concrete has better performance than the reference concretes, especially the mixture containing 3%. When nanosilica is incorporated in concrete, no features of damage could be captured.