Influence of different types of nano-modified coatings on hydrophobic and frost resistance of concrete.

Three different types of nano-particles including nano-SiO₂,TiO₂ and CaCO₃, and three organic film-forming coatings including ER,CR and AR were selected. The optimal content of nano-particles was determined by contact angle test. The water absorption and frost resistance of the nano-modified coating with the optimal content were tested. It was showed that nano-SiO2 had the best hydrophobic improvement effect among nano-SiO₂,TiO₂ and CaCO₃. Compared with concrete using ER,CR and AR coatings alone, the average water absorption rate decreases by 43.2%. The organic film-forming coating plus nano-SiO₂ particle composite coating had the most obvious improvement effect on the frost resistance of concrete. Under the optimal nano-SiO₂ content, the average relative dynamic elastic modulus is 82.5% after 100 freeze-thaw cycles. It was also found that there was a negative correlation between the water absorption rate and the relative dynamic modulus, and the concrete manifestation was that the stronger the hydrophobic property,the better the frost resistance. [ABSTRACT FROM AUTHOR]