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The tremie concrete placement method uses a vertical or nearly vertical pipe, through which concrete is placed by gravity feed below water level. [4]The lower end of the pipe is kept immersed in fresh concrete so that concrete rising from the bottom displaces the water above it, thus limiting washing out of the cement content of the fresh concrete at the exposed upper surface.
Schematic cross section of a pressurized caisson. In geotechnical engineering, a caisson (/ ˈ k eɪ s ən,-s ɒ n /; borrowed from French caisson 'box', from Italian cassone 'large box', an augmentative of cassa) is a watertight retaining structure [1] used, for example, to work on the foundations of a bridge pier, for the construction of a concrete dam, [2] or for the repair of ships.
Once a particular depth of trench is reached, a reinforcing cage is lowered into the slurry-filled pit and the pit is filled with concrete from the bottom up using tremie pipes. The heavier concrete displaces the bentonite slurry, which is pumped out, filtered, and stored in tanks for use in the next wall segment, or it is recycled.
Concrete floor of a parking garage being placed Pouring and smoothing out concrete at Palisades Park in Washington, DC Workability is the ability of a fresh (plastic) concrete mix to fill the form/mold properly with the desired work (pouring, pumping, spreading, tamping, vibration) and without reducing the concrete's quality.
The first residential building of slipform construction; erected in 1950 in Västertorp, Sweden, by AB Bygging Later picture of the residential building in Västertorp. Slip forming, continuous poured, continuously formed, or slipform construction is a construction method in which concrete is placed into a form that may be in continuous motion horizontally, or incrementally raised vertically.
The second main type of concrete pump, commonly referred to as a "line pump" or trailer-mounted concrete pump, is either mounted on a truck or placed on a trailer. This pump requires steel or flexible concrete placing hoses to be manually attached to the outlet of the machine and feed the concrete to the place of application. The length of the ...
Concrete has a limited lifespan between batching / mixing and curing. This means that ready-mixed concrete should be placed within 30 to 45 minutes of the batching process to hold slump and mix design specifications in the US, [15] though in the UK, environmental and material factors, plus in-transit mixing, allow for up two hours to elapse. [16]
Concrete is a mix of cement and water plus an aggregate such as sand or stone. Its compression strength means it can support heavy weights. [5] Insulating concrete forms (ICFs) cam be used for home construction. They are made by pouring concrete between rigid panels, often made out of polystyrene foam. Rebar can provide additional strength ...