Why Are Expansion Cuts in Concrete Necessary?
Concrete can shrink or expand with the changing temperature. This is why it is necessary to perform proper cuts in the concrete to allow for these changes. What are expansion cuts, expansion joints, and contraction joints? They are all different ways of preparing the concrete to handle any changes in temperature so that the structure or walkway is not compromised.
Concrete cuts are also called saw cutting. These cuts have to be done at predetermined spaces so that any shrinkage that occurs will not crack the concrete. These cuts can only be done after the material has been bolstered with enough strength to keep it from happening internally.
If the material and size of the concrete have to help the performance of nearby structures the concrete will need to be fixed with concrete joints to improve its stability. These joints also help stop cracks from happening. They are made by forming, tooling and placing joint formers in pre-planned cracks. This can also make the concrete look better.
These contraction joints have to be strategically placed. A rule is that they should be spaced about 24 or 30 times the thickness of the concrete slab. They are done this way to create weakened areas in the material so that cracks can be regulated.
They are tooled into the surface of the concrete at the time the concrete is placed down. They can also be sawed into the material when it hardens. This is why they are also called saw cuts.
Now that contraction joints have been explained, here is an explanation of what concrete expansion joints and cuts are. They allow the movement of adjoining slabs while minimizing cracks when movements occur. This also helps the concrete when it expands due to temperature changes. It will not put added stress on the system in place whether it is a sidewalk or a structure.
It should be evident that the reason the expansion cuts are necessary is the same reason the contraction joints are necessary. Each of them are placed when concrete is laid and either has set or the pour has been stopped longer than the initial set time for it.
These joints and cuts must always be designed by a structural engineer. As long as this is done, you will be able to construct your building or sidewalk with greater stability. You will also notice that the cuts, where positioned, can also make the concrete look more appealing to the eye.
Expansion cuts work just like contraction cuts do only in reverse. These necessary cuts should always be done between four and 12 hours once the concrete has been laid or poured.
Your engineer will give you the exact instructions for where to place the joints but there are some standard rules that are worth observing. For instance, the joints should be spaced between 10 and 15 feet apart. Always follow the exact plans for your particular project to assure greater stability and design appearance.
If you would like assistance with concrete cutting, please visit a concrete cutting website