Contraction Joints are joints placed in concrete at regular intervals so that concrete cracks where contraction joints are located instead of at random locations throughout the concrete.
Contraction Joints are used because slabs naturally have dimensional changes over time. When people refer to a “joint” in concrete they are generally referring to a contraction joint, which is the most common joint in concrete. Contraction joints can be created either during the forming process or after the concrete has been set using a concrete saw. Contraction joints are normally 25%-33% of the depth of a slab and as a general rule contraction joints are placed no farther apart than 2 to 3 times (in feet) the total width of the concrete slab (in inches).
A control joint in concrete to manage shrinkage cracks.
