Slab on grade without control joints (without pt) 2

[MonsieurR]

Can I achieve a slab on grade without control joints by placing sufficient steel mesh reinforcing?
I know there are solutions with SFRC + mesh without control joints. I also know documents claiming 0.5% steel mesh works without control joints.
Has anyone placed successfully concrete + steel mesh without control joints? withouth post tensioning.
It is for a tennis court.
Regards.

 

[Phil1934]

https://www.constructioncanada.net/four-ways-to-eliminate-joints-in-wide-slab-concrete-floors/

 

[oldestguy]

Check out continuously reinforced highway pavements. They can go for miles and no joints. However, there are small transverse cracks typically every 5 feet or so.

 

[oldestguy]

Here is a great manual on how to do it.

https://www.fhwa.dot.gov/pavement/concrete/pubs/hif16026.pdf

 

[Ron]

The short answer is no! Here's why....

It's a tennis court. Chances are the contractor is a guy who does residential slabs and driveways. Knows little or nothing about concrete technology. Will likely wet the concrete down so that it "pours" instead of being placed. That will increase shrinkage and therefore, cracking. Next, it is likely there will be no vapor barrier since it is outside. This means the subgrade restraint will be high, so therefore, more crack potential. Next....the wire mesh will likely be purchased in a roll....it will never be flat and with vary in its depth in the slab, most likely ending up at the bottom at the workers walk on it during placement.

Place the joints along the fault lines...that way you will at least have some control over the cracking, even though the pattern will be a bit unconventional for jointing.

Welded wire mesh does not prevent cracking...it only holds those cracks that do occur tighter together. Fibers do not prevent cracking....though steel fiber is more likely to prevent cracking or at least making the cracks farther apart than wire mesh will. Polypropylene fibers do little to prevent cracking.

If you must use wire mesh, specify that it be purchased in sheets and be placed from the top while the concrete is still plastic. Do not allow them to walk on it after placement. The slab can be floated without walking on it.

 

[ShawThing]

Probably can be done but not with mesh and the amount of reinforcement you might need might make it cost prohibitive.

You could provide a control/expansion joint in the middle of the court underneath the net position and saw cut joints at the fault lines as suggested above. If you filled the latter with a sealant, once the lines were painted they would hardly be noticeable.

 

[hokie66]

Sawcut joints might hardly be noticeable, but they would affect the ball bounce. Whether that is an acceptable solution depends on the standard of play this court will see. If for major tournaments, it would not be acceptable. For a playground, not a problem.

 

[Retrograde]

See attached.

 

[MonsieurR]

Thanks everyone!