Vinyl acetate polymers modified by siloxane for improving reinforced concrete: Water proofness and anticorrosion

Concrete, which is commonly destroyed by erosion in adverse environments, cannot satisfy the demands of foundation construction engineering applications. The optimal way   to ensure concrete's durability is to cover its surface with a barrier coating that prevents potentially harmful particles from penetrating the inside. Vinyl acetate polymers were applied as coatings owing to excellent flexibility and strong adhesion to the substrate. However, their hydrophilicity and low hardness will inevitably limit the usage in various areas, in particular the construction materials field. In this study, a method of modifying vinyl acetate polymers (PVAc) by vinyl triethoxysilane (VTES) and vinyl neononanoate (VeoVa-9), vinyl neodecanoate (VeoVa-10) in tertiary vinyl carbonates was reported to enhance the anticorrosion of concrete, where the former VTES could act a coupling agent, while the latter tertiary vinyl carbonates provide shielding against invasion through steric effect. Following modification, the hydrophilic PVAc becomes a hydrophobic coating with a contact angle as high as 98°; the coating's water absorption rate in one week is merely 1.25%; higher hardness and modulus were validated by nanoindentation measurements, while sandpaper friction and lap-shear trial indicated an enhancement in wear resistance and adhesion; three-electrode electrochemical analysis revealed that the modified coating has a 98% anti-corrosion efficacy, and its excellent anticorrosion performance is further confirmed by 480-hour salt spray test on reinforced concrete models.