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This template has been created for transclusion in the articles Concrete, Cement, and Silica fume. It replaces the file at right. That file had been tagged for translation to SVG format, as if it were a graphic. But since it is really a table, I have re-rendered it in wiki markup.
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) Mechanisms of formation of C-S-H phases: Alkali–silica reaction – Chemical reaction damaging concrete
900 to 1050 °C – the remaining calcium carbonate decomposes to calcium oxide (CaO) and CO 2. 1300 to 1450 °C – partial (20–30%) melting takes place, and belite reacts with calcium oxide to form alite (Ca 3 O·SiO 4) (also known as C3S in the Cement Industry). Typical clinker nodules. Alite is the characteristic constituent of Portland ...
ASR can lead to serious cracking in concrete, resulting in critical structural problems that can even force the demolition of a particular structure. [4] [5] [6] The expansion of concrete through reaction between cement and aggregates was first studied by Thomas E. Stanton in California during the 1930s with his founding publication in 1940. [7]
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.
Concrete is poured and reinforced with steel rods. The structure serves as the ground floor of the house and supports everything that sits on it. How does weather affect a house’s foundation?
It is used as a sealant in roads or on the shells of fresh eggs: when sodium silicate is applied as a sealant to cured concrete or egg shells, it chemically reacts with calcium hydroxide or calcium carbonate to form calcium silicate hydrate, sealing micropores with a relatively impermeable material. [16] [17]
When atmospheric carbon dioxide (CO 2), or carbonate ions (HCO − 3, CO 2− 3 dissolved in water) diffuse into concrete from its external surface, they react with calcium hydroxide (portlandite, Ca(OH) 2) and the pH of the concrete pore water progressively decreases from 13.5 – 12.5 to 8.5 (pH of water in equilibrium with calcite).