Search results
Results From The WOW.Com Content Network
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).
Concrete is a composite material composed of aggregate bonded together with a fluid cement that cures to a solid over time. Concrete is the second-most-used substance in the world after water, [1] and is the most widely used building material. [2] Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminium combined. [3]
The attack arises from soils containing SO2−. 4 ions, such as MgSO 4 or Na 2 SO 4 soluble and hygroscopic salts. The tricalcium aluminate (C 3 A) hydrates first interact with sulfate ions to form ettringite (AFt). Ettringite crystallizes into small acicular needles slowly growing in the concrete pores. Once the pores are completely filled ...
The alkali–silica reaction ( ASR ), also commonly known as concrete cancer, [ 3] is a deleterious internal swelling reaction that occurs over time in concrete between the highly alkaline cement paste and the reactive amorphous ( i.e., non-crystalline) silica found in many common aggregates, given sufficient moisture.
The material extrusion-based printing of concrete is currently favorable both in terms of availability of technology and of the cost-effectiveness. Therefore, most of the reinforcement techniques developed or currently under development are suitable to the extrusion-based 3D printing technology.
Leaky abstraction. In software development, a leaky abstraction is an abstraction that leaks details that it is supposed to abstract away. [1] As coined by Joel Spolsky, the Law of Leaky Abstractions states: [2] All non-trivial abstractions, to some degree, are leaky. This statement highlights a particularly problematic cause of software ...
In the United States, response codes are used to describe a mode of response for an emergency unit responding to a call. They generally vary but often have three basic tiers: Code 3: Respond to the call using lights and sirens. Code 2: Respond to the call with emergency lights, but without sirens. Alternatively, sirens may be used if necessary ...
Mullaperiyar Dam (IPA: [mulːɐpːeɾijɐːr]) is a masonry gravity dam on the Periyar River of Idukki district of Indian state of Kerala.It is situated 150km south east of Kochi and 200km north east of state capital city of Trivandrum.