Effectiveness of nanoparticles-based ultrahydrophobic coating for concrete materials

Moisture interaction and extreme weather may complicate the service life and increase the maintenance cost of various building materials. This paper investigates the performance of protective surface coatings applied to the most common building material, concrete. A novel synthesis route for producing ultrahydrophobic surface coatings is demonstrated to enhance the impermeability of concrete. The concrete specimens were chemically modified with silica sol, which was synthesized by hydrolysis of tetraethoxysilane (TEOS) under alkaline conditions, followed by treatment with hexadecyltrimethoxysilane (HDTMS) solution. The concrete specimens coated with proposed micro-composite coating were tested for hydrophobicity and self-cleaning characteristics in terms of contact angle and sliding angle at various water exposure conditions and periods of exposure. The permanency and efficiency of proposed coatings was further tested after exposure to alternate wet-dry cycles and highly saline environment. The modified specimens exhibited a contact angle of 121 degrees - 135 degrees and a sliding angle of 9 degrees - 22 degrees at various exposure conditions, depicting superior hydrophobicity. The overall findings of this study could aid in maintaining the intended longevity and performance of various concrete materials.