4.1. Mercury Intrusion Porosimetry (MIP)
Fig. 2 and Table 4 show the MIP results of the non-coated concrete surfaces
before exposure to physical sulfate attack. As expected, results showed higher content
of larger pores (1–0.1 lm) and mercury intrusion for concrete specimens made
with w/c = 0.60 compared with that of those made with w/c = 0.45. The total intrusion
volume of mercury dropped from 0.069 (m/Lg) to 0.038 (m/Lg) when the w/c
was lowered from 0.60 to 0.45. Approximately 50% decrease in pore volume was
observed for concrete made with w/c = 0.45 compared to that of concrete made
with w/c = 0.60. This difference was more pronounced for non-cured specimens.
Therefore, by increasing the w/c, the volume of the pores and their connectivity
can be increased, leading to higher capillary rise and increased salt growth on the
concrete surface, thus accelerating the damage mechanisms.