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If the surface of the concrete pour is insulated from the outside temperatures, the heat of hydration will prevent freezing. The American Concrete Institute (ACI) definition of cold weather placement, ACI 306, [128] is: A period when for more than three successive days the average daily air temperature drops below 40 °F (~ 4.5 °C), and
Each white lump marks the top of a deep ground-freezing tap. Cross section of a ground freezing pipe as used in the Big Dig. Ground freezing is a construction technique used in circumstances where soil needs to be stabilized so it will not collapse next to excavations, or to prevent contaminants spilled into soil from being leached away. [1]
ColorGraphics Weather Systems was a computer graphics company that pioneered the use of computer graphics for displaying weather forecasts on local television. [1] Formed in 1979 by Terry Kelly and Richard Daly, it is now part of Weather Central , another of Kelly's companies.
A pervious concrete street in 2005. Pervious concrete (also called porous concrete, permeable concrete, no fines concrete and porous pavement) is a special type of concrete with a high porosity used for concrete flatwork applications that allows water from precipitation and other sources to pass directly through, thereby reducing the runoff from a site and allowing groundwater recharge.
The first expanded polystyrene ICF Wall forms were developed in the late 1960s with the expiration of the original patent and the advent of modern foam plastics by BASF. [citation needed] Canadian contractor Werner Gregori filed the first patent for a foam concrete form in 1966 with a block "measuring 16 inches high by 48 inches long with a tongue-and-groove interlock, metal ties, and a waffle ...
The earliest known example is 3D Art Graphics, a set of 3-D computer graphics effects, written by Kazumasa Mitazawa and released in June 1978 for the Apple II. [6] [7] Virtual Reality 3D is a version of 3D computer graphics. [8] With the first headset coming out in the late 1950s, the popularity of VR didn't take off until the 2000s.
Windows: Windows 7 and newer Mac: MacOS X and newer Note: Ad-Free AOL Mail removes ads while using AOL email; it is not supported on AOL Desktop Gold or the AOL mobile app.
Shotcrete, gunite (/ ˈ ɡ ʌ n aɪ t /), or sprayed concrete is concrete or mortar conveyed through a hose and pneumatically projected at high velocity onto a surface. This construction technique was invented by Carl Akeley and first used in 1907. [1]: 7 The concrete is typically reinforced by conventional steel rods, steel mesh, or fibers.