Congestion in Concrete Members is caused by structural and seismic design requirements, embedded conduits and pipes, and box-out. To achieve structurally sound and aesthetically pleasing concrete, contractors need to practice special care and consideration when pouring concrete in congested areas.
The concrete should also be placed in its final position to ensure that it is high flow-able. Good detailing by the designer and good planning and control by contractors are the key aspects of concrete consolidation in congested areas.
Various Causes of Congestion of Concrete
Reinforcement Congestion
Steel congestions in reinforced concrete elements result from seismic and structural requirements. Steel congestions occur where additional reinforcement is necessary.
In some cases, this may occur around formed openings, especially in thin wall sections, between columns and other concrete members, at beam’s intersections, in deep beams, in mat foundations, in post-tensioned members, and deck slabs of bridges.
When seismic or structural design uses columns, ties are frequently used at their tops and bottoms. Instead of closely spaced steel bars, concrete covers use cement and sand grout. That would lead to drying shrinkage in the concrete cover, followed by cracking and crazing on the surface, and, ultimately, loss of durability.
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