Salt-scaling resistance of biomimetic PEG-PVA-modified concrete

Concrete exposed to deicing salts during freezing and thawing cycles is prone to salt-scaling damage. The superficial damage of salt scaling can lead to further deterioration through increased ingress of water and harmful ions (e.g.., chloride), thereby decreasing the long-term durability of concrete. Commonly, air-entraining admixtures (AEAs) are prescribed to prevent salt scaling. While previous research has substantiated that biomimetic antifreeze polymers can provide internal freeze–thaw protection to concrete exposed to cyclic freezing and thawing through the prevention of ice nucleation and growth (in lieu of AEAs), no studies yet report on the salt-scaling resistance of concrete modified with biomimetic antifreeze polymers, such as poly(ethylene)-graft-poly(vinyl alcohol) (PEG-PVA). Here, the effect of water- and polymer-to-cement ratio on the salt scaling resistance of PEG-PVA-modified concrete was investigated and compared to plain and AEA-modified concrete. At a water-to-cement ratio (w/c) of 0.45 (i.e., below the onset of more severe salt scaling damage at w/c = 0.5) the addition of PEG-PVA (0.066% by weight of cement) to concrete improved air-void parameters (i.e., specific surface area and spacing factor) while reducing water absorption over 14 days to significantly below that of traditional AEA-modified concrete. Furthermore, in 0.55 w/c concretes, the addition of PEG-PVA (0.066% and 0.10% by weight of cement) reduced salt-scaling to a degree comparable to that of 0.45 w/c concrete.