Effect of leaching on the composition of hydration phases during chloride exposure of mortar

Phase changes in cementitious materials exposed to saline solutions

“…As mentioned earlier, an increase of KOH concentrations in exposure solutions limited the observed leaching of portlandite strongly [68,128], as also shown in Fig. 14b.…”

“…The chloride content was determined on the profile ground sections with increasing depth from the exposed surface using potentiometric titration, b) Portlandite (CH) profiles determined on the same batch of profile ground mortar powder using TGA. Adapted from [128]. pH values in the interface and its proximity.…”

“…Increasing the hydroxyl concentration in the exposure solution was also observed to slow down the ingress of ions such as chloride (see Fig. 14a), thereby indicating a strong link between leaching and ingress of ions [68,128].…”

Long-term performance of reinforced concrete under a de-icing road environment

“…After four winters from 1996 to 2000, a new technique was used for spreading the de-icing salts and the average dosage was reduced to a half of the previous winters [13], so this may result in a lower free chloride concentration in pore solution. However, the free chloride in pore solution accounts for <10 % of total chloride content, and the main contribution is from bound/absorbed chloride in solid phase (AFm and C-S-H) [33]. Therefore, this interesting difference may result from phases change after a long-term interaction and leaching, such as decomposition of chloride-containing AFm, leaching of portlandite and decalcification in C-S-H [33,34].…”

“…However, the free chloride in pore solution accounts for <10 % of total chloride content, and the main contribution is from bound/absorbed chloride in solid phase (AFm and C-S-H) [33]. Therefore, this interesting difference may result from phases change after a long-term interaction and leaching, such as decomposition of chloride-containing AFm, leaching of portlandite and decalcification in C-S-H [33,34]. Moreover, the carbonation in the near surface zone is also one of the main factors.…”