(09-14-2011, 06:41 PM)eaadams Wrote: That is interesting. I have always been told that a joint filler should be crushable so that it will not pucker up with reverse curl when the moisture reequilibtates. See ACI 302.2 and the article http://www.google.com/m/url?client=ms-android-sprint-us&devlocsession=off&ei=31dxTujvB-b_sgfI8MupAg&gl=us&hl=en&q=http://www.silpro.com/education/Reverse_Curl_Article.pdf&source=android-launcher-search&ved=0CBYQFjAA&usg=AFQjCNFWXNBRlIEHEd-mkXHyIuwI8ckBkw
The article doesn't offer a joint filler material suggestion. The forces encountered when a slab relaxes are variable depending on the moisture movement rate within the slab and the amount of displacement during the warping phase, but I still stand by my recommendation that joints be filled with a semi-rigid two-part material.
Relaxation is only one factor a control joint may be subject to. There may also be a separation at the joint, which is why the joint was installed in the first place. In either case you want a material that is as strong as it can be yet it must not be as strong as the concrete itself or you will risk damaging the concrete.
If by 'crushable' you are meaning a patch material, I say nay nay While a soft material will be easily crushable it will retain no strength after being crushed, so if a joint is moving seismically by a small amount (vibrations, flexing) the patch will break down and fail to support rolling loads. A semi-flexible two-part filler will absorb small variations in movement. Also, a patch will still displace out of a joint when crushed as it has no where else to go.
(09-14-2011, 07:09 PM)Ernesto Wrote: There's the ole saying. "Honor the joint". Can't tell ya how many of those I've seen. Thats why I would never fill it with concrete. The ceramic tile industry has addressed this.
Stephen, I believe you are thinking of moving joints such as unreinforced cold joints and transitional joints. These are designed to move and the structural integrity of the building may rely on their ability to move. These types of joints may be filled with a soft filler (as recommended by the architect) which will keep debris out of the joint and still allow movement, but yes the joint may very well move and will move the flooring with it.
Concrete Answers for Flooring Problems