The maximum spacing of the joint should be 24 to 36 times the thickness of the slab.
Joints should be 10 feet apart and a maximum of 15 feet apart.
When using the joint groove for contraction joints, the joint must have a minimum depth of 1/4 the thickness of the slab.
Saw joints must be made within 4 to 12 hours after finishing the concrete.
Keyed joints are not recommended for industrial floors.
Dry cutting joints should be made between 1 and 4 hours after finishing.
The filling of the precast joint must be used to separate the slabs from the walls or feet of the building. Put 2 inches of sand in motion to prevent attachment to the foot.
If the slab contains wire mesh, it is recommended to discontinue it through the contraction joints.
The joint spacing must also be chosen so that the concrete sections are approximately
It is recommended to have concrete joints along the lines of the column, sawn, or keyed.
Metal dowels should be used on slabs that carry heavy loads.
Plan the exact locations of all joints, including when to cut the saw.
Use Isolation joints between slabs and columns, walls, and sidewalks and where sidewalks or sidewalks meet other concrete structures.
The materials used in the concrete joints must be flexible enough to absorb or deform as needed and then be able to restore the original state.
Always look for materials that are permeable, and that can adhere to the concrete.
The surface of the hardened concrete must be clean, rough and free from any deposits. It should have aggregate finish.
The fresh pour must be properly bonded and compacted against the hardened concrete to attain full strength. Anchor bars are usually left projecting to ensure this in case of reinforced concrete work.
The surface finish of the joints must be properly finished to disguise the joint and smoothed. In case of water retaining structures like tanks and basement walls, water stops are introduced at the joints to prevent seepage of water.