Influences of modified nanoparticles on hydrophobicity of concrete with organic film coating

To study the influences of modified nanoparticles on hydrophobicity of concrete with organic film coating, nanocomposite organic film coatings were prepared with three types of organic polymer paints and two types of nanoparticles. Surface contact angles and water absorption of concrete coated with such coatings were tested. Fourier transform infrared spectrum experiment was also carried out to check modification effects on nanoparticles. Results indicated that hydrophilic nano-SiO2 and nano-TiO2 can be modified effectively to become hydrophobic by silane coupling agent KH-570. Incorporation of nanoparticles can enhance contact angles on coated concrete and reduce water absorption by increasing degree of surface roughness of coatings, whereas nano-SiO2 is relatively more effective than nano-TiO2 in modifying surface properties of coatings. However, a dosage limit exists for nanoparticles in coating, and observed improvements decreased when dosage reached beyond the limit.