Frost Resistance of Concrete Reinforced Using Surface-Strengthening Materials in Airport Pavements

Abstract

In cold regions, freeze-thaw cycles cause airport pavements to exhibit numerous failure modes on the surface, thus affecting the normal operations of the airports. To repair surface damage to airport pavements quickly, efficiently, and cheaply, surface-strengthening materials may be added to the concrete to improve its frost resistance. In the current study, several such materials, namely, concrete protectant, polyurea, epoxy resin, and silane (main ingredients), were tested for their performance in pavement concrete samples. A one-sided freeze-thaw cycle experiment was designed and the mass loss, relative dynamic elastic modulus, saturation, and diffusion coefficient were used to evaluate the frost resistance of the reinforced concrete. In order to calculate the diffusion coefficient, the existing diffusion model was extended to take into account moisture diffusion in concrete during freeze-thaw cycles. The mechanisms of frost resistance were further investigated with the help of scanning electron microscopy (SEM). The results showed that after surface treatments, mass loss and saturation of the concrete decreased, while its relative dynamic elastic modulus increased. The diffusion coefficient exhibited a minimum value with the increase in the number of freeze-thaw cycles, with a cutoff around the 42nd cycle. The results demonstrated that for the selected concrete and four strengthening materials, the condensation reaction products of the silane in particular increased the water and frost resistance of the concrete significantly compared with other surface-strengthening materials. The mass loss of concrete was reduced by 66% and the relative elastic modulus was increased by 64.8% for the silane reinforced sample compared with the unreinforced concrete. The saturation and diffusion coefficient of the concrete were also reduced, demonstrating that, among all materials tested in this research, the silane is the most suitable material for surface strengthening of the airport concrete pavement selected for the research, and its optimum dosage is 4 m2/kg.