Fig 1.
Absorption spectra of the resin-coated mortar specimens in the near-infrared region before UV irradiation.
Blue line (a): non-coating; yellow line (b): thin coating; green line (c): normal coating; red line (d): thick coating. Grid lines indicate 4338 cm-1 and 4264 cm-1.
Fig 2.
Photographs of the surfaces of the (a) non-coating, (b) thin coating, (c) normal coating, and (d) thick coating specimens before UV irradiation. Photographs of the surfaces of the (e) non-coating, (f) thin coating, (g) normal coating, and (h) thick coating specimens after UV irradiation. The sides of each core were protected with aluminum foil, to restrict the UV radiation to the coated surface of the mortar specimen.
Fig 3.
Absorption spectra of the resin-coated mortar specimens in the near-infrared region after UV irradiation.
Blue line (a): non-coating; yellow line (b): thin coating; green line (c): normal coating; and red line (d): thick coating. Grid lines indicate 4338 cm-1 and 4264 cm-1.
Fig 4.
FTIR spectrum of the surface of the specimen with normal coating before UV irradiation ((a)blue line) and after UV irradiation ((b)yellow line).
Fig 5.
Permeability of the specimens with normal coating before (blue line) and after UV irradiation (red line).
Here, the circle indicates measurements taken using the coated surface of the mortar specimen, while the triangle indicates measurement taken using the inner portion of the specimen without a coating.
Fig 6.
Electron probe microanalyzer image of chloride ion penetration in the resin-coated mortar specimens: (a) specimen with normal coating before UV irradiation, (b-1) noncoated specimen after UV irradiation, (b-2) specimen with thin coating after UV irradiation, (b-3) specimen with normal coating after UV irradiation, and (b-4) specimen with thick coating after UV irradiation.
Fig 7.
SEM and elemental EDX mapping images before (a)-(e) and after (f)-(j) UV irradiation. (a) and (f) are backscattered electron images. (b) and (g) are secondary electron images. EDX mapping images of C (c) and (h), Ca (d) and (i), and O (e) and (j). Color scale indicate the intensity of characteristic X-ray (arbitrary unit).
Fig 8.
The enlarged (high magnification) image of Fig 7.
(a) and (b) before UV irradiation, (c) and (d) after UV irradiation. (a), (c) backscattered electron image, and (b), (d) secondary electron image.
Fig 9.
Absorption spectrum of the base material (blue) (a), main agent (yellow) (b), and topcoat (green) (c), of the acrylic coating in the near-infrared region.
Fig 10.
Schematic diagram of paint layers on a concrete plate modeling: (a-1) severe peeling damage (only the base material remains on the structure), (a-2) moderate peeling damage (the base material and the main agent remain), (a-3) erroneous application (no main agent is included in the resin), and (a-4) an undamaged coating (all layers applied correctly). (b) Absorption spectra of (a-1), (a-2), (a-3), and (a-4) in the near-infrared region (green (a), yellow (b), red (c), and blue (d), respectively).