Views: 13 Author: Site Editor Publish Time: 2017-03-25 Origin: Site
Determine Where to Saw Cut
Before you start saw cutting concrete, is important to select where these cuts will be done. It is recommended to start saw cuts on or at the center of column lines.
Joints shall be spaced at 24 to 36 times the slab thickness but this need to be confirmed by a structural engineer. Joint spacing normally ranges between 10 to 18 feet depending on the amount of reinforcement the slab has. If you are using high shrinkage concrete, you might want to decrease the cut spacing. Here are other factors to will help you determine where to saw cut:
· Try to form square patterns
· Make saw cuts continuous
· It is important to select an area that doesn’t have continuous steel reinforcement from one slab or square to another
· It is better to have smaller cracks than to increase cost by having and maintaining several joints.
· Under hot weather conditions, you might want to try forming a larger square and then cutting interior joints. By doing this you will be controlling fast setting concrete cracks in larger areas.
How to Saw Cut Concrete
Once you know the joints to be saw cut, mark them using a chalk line. If using water cutting equipment, make sure that the water is running all the way down to the blade. Allow the blade to get its required depth and start walking or moving the equipment following the chalk like mark. Here are some recommendations when saw cutting concrete:
· Do not twist the saw blade.
· Do not let the blade spin in the cut, as this will increase wear on the bond.
· When cutting concrete with heavy rebar use blades with soft metal segment bonds
· When cutting concrete with heavy rebar use blades with soft metal segment bonds use required PPE.
How Deep Does the Saw Cut Need to be?
A good rule of thumb is to cut the joint one-quarter to one-third the slab thickness. Check that the saw cut depth is sufficient and according to the structural engineer recommendation. If the joint is too deep, aggregate interlocking will not be enough to transfer loads. However, when the saw cut is too shallow, random cracking might occur.
Factors such as curing techniques, slab thickness, slab length, and base type shall be analyzed before selecting where these joints should be cut.