A Study on Impact of Different Surface Treatment Agents on the Durability of Airport Pavement Concrete

Concrete surface treatment is one of effective methods to increase the durability of concrete. This study chose tetraethyl orthosilicate (TEOS), lithium silicate (Li2SiO3), SiO2 nanoparticles (nano-SiO2) as surface treatment agents, tested their resistance to water penetration, chloride ion penetration, frost, sulfate erosion and abrasion of concrete specimens with different strengths, compared and evaluated the impacts to the durability of concrete by using three surface treatment agents, researched the impact of concrete strength on the surface treatment effects, and analyzed the mechanism of these surface treatment agents in connection with microscopic tests. It was found that all three agents can improve the durability of concrete, of which, the treatment effect from using tetraethyl orthosilicate (TEOS) was the best; however, along with the improvement of concrete strength, its other effects were gradually reinforced except for some small improvement effect in resistance to frost, which means it is an ideal concrete surface treatment agent; for lithium silicate (Li2SiO3), the improvement effect of resistance to frost was the best with little impact on the strength of the concrete, however, the other performance improvement effects were a little bit worse than that of tetraethyl orthosilicate (TEOS), which means it is more suitable for airport pavement with a higher concrete resistance to frost; For SiO2 nanoparticles (Nano-SiO2), the surface treatment effect was extreme limited, not recommended to be solely used for airport pavement with its requirement of high resistance to frost. Upon scanning electron microscope (SEM), X-ray diffraction (XRD), fourier transform infrared radiation (FTIR) and thermo gravimetric analyzer (TGA) tests, the surfaced concrete specimens did not produce any new substances, and the effect of the surface treatment agents was mainly to improve the concrete performance by physical filling, or by filling the cavities with the hydrated calcium silicate gel produced in the chemical reaction. These results may direct the selection of surface treatment agents in airport engineering.