Control joints in concrete basement slab
We are building a house and I have been learning a bit more about concrete lately. You may know the old saying ‘there is only one sure thing with concrete, it WILL crack’. 😉 Of course the trick is getting it to crack where you want to 🙂
‘Control joints’ are cuts made in the concrete so that hopefully when the slab cracks it will follow the pre-made cut. This is the control joint layout that I came up with:
Black lines indicate control joints
The idea is to control cracking at the inside corners as well as near the thickened slab portions of the basement.
Please disregard the fisheye distortion in the photo as the foundation is actually square 🙂
Also, here are some articles that I found interesting:
Control joints
Additives
“Superplasticizers, also known as plasticizers or high-range water reducers (HRWR), reduce water content by 12 to 30 percent and can be added to concrete with a low-to-normal slump and water-cement ratio to make high-slump flowing concrete. Flowing concrete is a highly fluid but workable concrete that can be placed with little or no vibration or compaction. The effect of superplasticizers lasts only 30 to 60 minutes, depending on the brand and dosage rate, and is followed by a rapid loss in workability. As a result of the slump loss, superplasticizers are usually added to concrete at the jobsite.”
Source: http://www.cement.org/cement-concrete-basics/concrete-materials/chemical-admixtures
Radiant Heating Tubing (PEX etc.) and Control Joints
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