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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.
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).
A prompt reaction initiated at the early stage of concrete hardening on very fine silica particles will help to suppress a slow and delayed reaction with larger siliceous aggregates on the long term. Following the same principle, the fabrication of low-pH cement also implies the addition of finely divided pozzolanic materials rich in silicic ...
Sunset legislation passed by the Texas Legislature in 2001 changed the agency's name to the Texas Commission on Environmental Quality and continued the agency until 2013. During the special session of the 81st Legislature (2009), legislation was adopted amending the 2013 date to 2011, [ 4 ] when the agency was continued for an additional 12 ...
The heat during Texas summers can shrink the ground around your house that can lead to cracks and costly repairs. In Texas, watering your home’s concrete foundation can save you on costly ...
An example is when slaked lime (calcium hydroxide) is mixed into a thick slurry with sand and water to form mortar for building purposes. When the masonry has been laid, the slaked lime in the mortar slowly begins to react with carbon dioxide to form calcium carbonate (limestone) according to the reaction: Ca(OH) 2 + CO 2 → CaCO 3 + H 2 O.
Silicon carbonate is a crystalline substance formed under pressure from silica and carbon dioxide. The formula of the substance is SiCO 4 . To produce it silicalite is compressed with carbon dioxide at a pressure of 18 Gpa and a temperature around 740 K (467 °C; 872 °F).
The only other major sink of silica in the ocean is burial along continental margins (3.6 ± 3.7 Tmol Si year −1), primarily in the form of siliceous sponges. [15] Due to the high degrees of uncertainty in source and sink estimations, it's difficult to conclude if the marine silica cycle is in equilibrium.