Surface treatment of permeable coatings -- an experiment of removing ice salt

   In order to evaluate the long-term performance of the surface treatment of the permeable coating, Johnnsson field test was carried out in the Swiss Eugenia tunnel, and the area was about four months of the year. Figure 4.37 shows the chloride content and distribution of the surface treated and untreated concrete (W/C=40.45) in the field test for one year and three years (the effective penetration depth of silane is 2~3mm).

       As can be seen from figure 4.37, the effect of penetration resistance of chloride ion is very obvious. Due to water erosion by rain or a vehicle, the concentration of chloride ions on the surface of concrete specimens is often low, which is called "erosion" effect. However, it can be seen from the figure that the so-called "wash" effect of the surface treatment is not obvious, and the concentration of chloride ion in the outer surface is the biggest. The peak value of chloride ion content in the surface treated samples is located at the 5mm of the outer surface, which reflects the "erosion" effect.

        Laboratory tests showed that the performance of concrete against chloride ion was greatly improved after the surface treatment, and the long-term field experiment mostly reflected its fine effect. In view of the long time of application of permeable coatings in practical engineering, it is necessary to carry out a long-term experiment in order to further verify the surface treatment effect and its long-term effectiveness.