Silane and methyl-methacrylate based nanocomposites as coatings for concrete exposed to salt solutions and cyclic environments

This study aimed at investigating the efficiency of polymeric nanocomposites as superficial treatments for concrete subjected to aggravated exposures. Silane and methyl-methacrylate were used as base resins, in which nano-clay and nano-silica particles were mixed at different concentrations (0, 5, and 10%). The nanocomposites were applied to inferior and good quality [water-to-binder ratios of 0.60 and 0.40, respectively] concretes, and their effects on transport/barrier properties were evaluated in terms of penetrability and absorption/desorption percentages. Moreover, the durability of coated concrete was assessed under severe conditions: physical salt attack (PSA) and salt-frost scaling. The degradation mechanisms and coatings' functionality were studied by mineralogical, thermal, and microstructural tests. Results showed that silane/nanocomposites were effective at enhancing the barrier properties of concrete, thus mitigating PSA and salt-frost scaling for sound and cracked concretes. Methyl-methacrylate/nanocomposites, especially at 5% dosage, were efficient at resisting PSA of concrete; but, they failed in the salt-frost scaling exposure.