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Self-consolidating concrete or self-compacting concrete (SCC) [1] is a concrete mix which has a low yield stress, high deformability, good segregation resistance (prevents separation of particles in the mix), and moderate viscosity (necessary to ensure uniform suspension of solid particles during transportation, placement (without external compaction), and thereafter until the concrete sets).
The thick bed mortar method has been around for hundreds, if not thousands of years. Historically, a sand/cement mixture was mixed with water to a fairly dry consistency and was spread on either a portland cement water paste (neat cement), or over cement powder spread on the surface which is then sprayed with water to create a slurry coat and spread over the surface. [1]
Concrete mixers generally do not travel far from their plant, as the concrete begins to set as soon as it is in the truck. Many contractors require that the concrete be in place within 90 minutes after loading. Some trucks in dry climates are equipped with the capability of adding water in spray form during the trip, especially on long trips.
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]
Hand-pushed broadcast spreader. A broadcast seeder, alternately called a broadcaster, broadcast spreader or centrifugal fertilizer spreader (Europe) or "spinner" (UK), is a farm implement commonly used for spreading seed where no row planting is required (mostly for lawns and meadows: grass seeds or wildflower mixes), lime, fertilizer, sand, ice melt, etc., and is an alternative to drop ...
Segregation in concrete is a case of particle segregation in concrete applications, in which particulate solids tend to segregate by virtue of differences in the size, density, shape and other properties of particles of which they are composed. when the workability of concrete is high under pouring conditions, or the amount of mortar is larger than the void volume of coarse aggregate, or the ...
These walk-behind, towable, mounted, and handheld salt spreaders are the best ahead of storms. After shoveling, applying ice melt is critical for safety. These Expert-Recommended Salt Spreaders ...
A w/c ratio higher than 0.60 is not acceptable as fresh concrete becomes "soup" [2] and leads to a higher porosity and to very poor quality hardened concrete as publicly stated by Prof. Gustave Magnel (1889-1955, Ghent University, Belgium) during an official address to American building contractors at the occasion of one of his visits in the ...