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2. Concrete degradation - Wikipedia

   en.wikipedia.org/wiki/Concrete_degradation

   The sight of calthemite is a visual sign that calcium is being leached from the concrete structure and the concrete is gradually degrading. [12] [17] In very old concrete where the calcium hydroxide has been leached from the leachate seepage path, the chemistry may revert to that similar to "speleothem" chemistry in limestone cave.

3. Calcium hydroxide - Wikipedia

   en.wikipedia.org/wiki/Calcium_hydroxide

   Calcium hydroxide (traditionally called slaked lime) is an inorganic compound with the chemical formula Ca 2. It is a colorless crystal or white powder and is produced when quicklime (calcium oxide) is mixed with water. Annually, approximately 125 million tons of calcium hydroxide are produced worldwide. [8]

4. Carbonatation - Wikipedia

   en.wikipedia.org/wiki/Carbonatation

   Carbonatation is a slow process that occurs in concrete where lime (CaO, or Ca(OH) 2 ) in the cement reacts with carbon dioxide (CO 2) from the air and forms calcium carbonate. The water in the pores of Portland cement concrete is normally alkaline with a pH in the range of 12.5 to 13.5.

5. Calcium silicate hydrate - Wikipedia

   en.wikipedia.org/wiki/Calcium_silicate_hydrate

   Other calcium aluminium silicate hydrate, (C-A-S-H) minerals: Hydrogarnet – Calcium aluminium garnet; Hydrotalcite – Hydrated Mg-Al layered double hydroxide (LDH) containing carbonate anions; Tacharanite – Calcium aluminium silicate hydrate mineral (Ca 12 Al 2 Si 18 O 33 (OH) 36, and also Ca 12 Al 2 Si 18 O 51 (OH) 2 · 18 H 2 O)

6. Alkali–silica reaction - Wikipedia

   en.wikipedia.org/wiki/Alkali–silica_reaction

   When pH slowly drops due to the progress of the silica dissolution reaction, the solubility of calcium hydroxide increases, and the alkali gel reacts with Ca 2+ ions. Its viscosity increases due to gelation process and its mobility (fluidity) strongly decreases when C-S-H phases start to precipitate after reaction with calcium hydroxide ...

7. Pozzolanic activity - Wikipedia

   en.wikipedia.org/wiki/Pozzolanic_activity

   The pozzolanic activity is a measure for the degree of reaction over time or the reaction rate between a pozzolan and Ca 2+ or calcium hydroxide (Ca(OH) 2) in the presence of water. The rate of the pozzolanic reaction is dependent on the intrinsic characteristics of the pozzolan such as the specific surface area , the chemical composition and ...