Salt-frost resistance and mechanism analysis of super-hydrophobic pavement cement concrete for different deicing salts

This research presents a method to solve the problem of poor durability of cement pavement caused by long-term use of deicing salt as well as improve the salt-frost resistance of self-developed super-hydrophobic material used for cement concrete pavement. The specimens of super-hydrophobic pavement cement concrete (SPCC) are prepared under laboratory conditions. The ability of the SPCC specimens to resist the salt freezing for three kinds of deicing salts is investigated. Through the salt-frost resistance test (slow freezing method), when the rates of salt freezing are 0, 50, 100, 150, and 200 times respectively higher than the ordinary rate, the mass loss rate and compressive strength loss rate of the specimens are calculated, and the surface erosion condition of the specimens is observed. The surface morphology and microstructure of the SPCC specimens are analysed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the compressive strength loss rate of the SPCC specimens is only about 40% that of ordinary pavement cement concrete (OPCC) specimens under the same conditions, and that the super-hydrophobic material can significantly improve the salt-frost resistance of the SPCC specimens. The crystal structures of the SPCC specimens are the same as those of the OPCC specimens. The micro-nano second-class rough structure formed by the self-developed super-hydrophobic material is the key to improving the salt-frost resistance of the SPCC specimens. The research results demonstrate that applying super-hydrophobic concrete to roadways in cold regions can improve the salt-frost resistance of SPCC.