The allowable crack width is the maximum crack width that a reinforced concrete member can tolerate before being subject to significant adverse effects.
What is the Maximum Crack Width?
Since concrete is weak in tension, tensile forces can easily overcome the interlocking forces between the cementitious material and aggregates.
Cracks are visually unappealing and can cause alarm for building occupants. If the cracks are allowed to propogate and grow, water infiltration can exasperate the issue and eventually pose corrosion risks as water may permeate down to the rebar.
It is impossible to avoid cracking, however, we can reduce the amount of cracking to a reasonable minimum. The following are typical limits for indoor and outdoor RC members:
- Indoor: 0.3 mm
- Outdoor: 0.5 mm
Note: For prestressed concrete structures, the design cracking widths are more onerous. In general, crack widths for prestressed members are limited to 0.2 mm.
Additional Material
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