Youtor
pumping concrete
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Concrete mixture should neither be too harsh nor too sticky; also, neither too dry nor too wet • A slump between 50 and 150 mm is recommended (note that pumping induces partial compaction, so the slump at delivery point may be decreased) • If the water content in the mixture is low, the coarse particles would exert pressure on the pipe walls. Friction is minimized at the correct water contents. The presence of a lubricating film of mortar at the walls of the pipe also greatly reduces the friction • High cement content in concrete is generally beneficial for pumping • Water is the only pumpable component in the concrete, and transmits the pressure on to the other components • Two types of blockage to efficient pumping could occur: (1) Water can escape from the mixture if the voids are not small enough; this implies that closely packed fines would be needed in the mixture to avoid any segregation. The pressure at which segregation occurs must be greater than that needed to pump concrete. (2) When the fines content is too high, there could be too much frictional resistance offered by the pipe. The first type of blockage occurs in irregular or gap-graded normal strength mixtures, while the second type occurs in high strength mixtures with fillers. In order to avoid these two types of failure, the mixture should be proportioned appropriately • Other mixture factors that could affect pumping are the cement content, shape of aggregate, presence of admixtures such as pumping aids or air entrainment. Air entrainment is helpful in moderate amounts, but too much air can make pumping very inefficient • When flowing concrete is being pumped, an over-cohesive mixture with high sand content is recommended. For lightweight aggregate concrete, pumping can fill up the voids in the aggregate with water, making the mixture dry. • • Real civil • / @realcivil • 1.How to check column verticality • • how to check column verticality! • 2.Construction of canal full video • • Water Canal | Channel Making Machine ... • 3.How to check level of slab on site • • How to check level of slab: rcc slab ... • 4.Ready mix concreting on site • • Ready mix concrete for building roof ... • 5.Dado work video • • dado work | what is dado work | tiles... • 6.Stirrups cutting length • • Видеоклип • 7. How to setup Formwork for beam and slab • • Formwork Concrete Beam Construction ... • 8. Steps involved in plastering • • how to do wall Plastering and differe... • 9.chair bars: reinforcement chairs it's function and specifications • • chair bars : reinforcement chairs its... • 10. Hidden beams • • hidden beams and its purpose : reinfo... • 11. Flooring renovation No cement No sand • • Renovation project house : floor tile... • Our face book page : real civil : @civilnerd • Our telegram page : civil engineering video : t.me/realcivil
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