The silane water-repellent agent achieved excellent protection
of the concrete against physical sulfate attack since none of the cylinders
(cured and non-cured) coated with silane have experienced
surface scaling or mass change. The protection mechanism of
silane is different from that of the other coating materials tested
in this study as it penetrates the concrete surface and chemically
reacts within the concrete pores, providing molecules that perform
as a water repellent [20,42]. Thus, it can prevent the water that
contains sulfates from entering into the concrete pores, mitigating
capillary rise and salt crystallization. However, previous studies
have shown that the performance of water repellant agents can
vary depending on their formulation and type of application.