Strength and Durability of a 70% Ground Granulated Blast Furnace ...

Salt Scaling
Salt scaling resistance was determined by utilizing the procedure in accordance with
ASTM C 672-92. Three replicate test panels were made per mix type at the construction
site. After casting, the concrete was struck off using a wooden strike-off board. After the
bleed water had disappeared, the concrete surface was finished with three passes of the
wooden strike-off board, followed with a medium-stiff brush finish and immediately
covered with plastic sheeting. The panels were demolded after 20 to 24 hours and moist
cured for 14 days at 23 ± 1.7˚ C [73 ± 3˚ F]. After moist curing, the panels were cured in
air at the same temperature and at 45% to 55% relative humidity for 14 days. A calcium
chloride solution was ponded in the test panels to a depth of 6.4 mm [¼ in.]. The ponded
area of each panel was determined. The panels were then subjected to 16 to 18 hours of
freezing followed by 6 to 8 hours of thawing at 23 ± 1.7˚ C [73 ± 3˚ F] and 45% to 55%
relative humidity. Every 5 cycles the panels were flushed, weighed, and the panels were
inspected visually. The loose fines were also weighed. The cycling was continued to only
25 cycles because the panels had exceeded the terminal rating of 2.5 Equivalent Visual
Rating (EVR). Panel mass loss in grams was accumulated and converted to a square foot
basis. The mass loss was then converted to EVR. The conversion factor is one EVR= 65
g/ft 2 /cycle. In Figure 5 is shown a typical salt scaling test specimen.
Fig. 5-Salt scaling specimen
Rapid Chloride Permeability
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