4.2. Visual inspection
Table 5 shows the visual rating for each concrete cylinder after six months of
physical sulfate exposure using the Malhotra et al. [24] rating system. After one
month of exposure (i.e. four cycles of wetting and drying), surface scaling appeared
on the drying surfaces of the non-coated cylinders (both cured and non-cured)
made with w/c = 0.60, with more substantial degradation for the non-cured cylinders.
However, no deterioration was observed on the coated cylinders. After six
cycles, damage appeared on the acrylic coated specimens (for both the cured and
non-cured cylinders) as shown in Fig. 3.