I am looking for repair suggestions as well as possible cause of spalling of control joints in a concrete floor in a factory. Spalling is occuring at nearly all of the joints in the aisles only. The concrete is 6" thick 4000 psi concrete, with welded wire fabric reinforcement at 3" depth, with metal hardener, approx. 18 years old. Spalling started several years ago, and has become more of a problem lately.Things that have changed in the last two years: increased sweeper/scrubber activity in the aisles (water only, no cleaning chemicals), weekly polishing of the concrete surface (with HTC twister diamond pads. The concrete floor is subjected to solid tire forklift traffic and tugger and dollie traffic. Aisles cannot be shut down to traffic longer than a day for repairs. Thanks in advance to any advice and experience with this.
Update: Thanks for the suggestions so far. The slab has not curled. There are some crazing areas in the slabs. The floor has been in use many years without issue. Only in the last couple of years has this spalling started. The only areas showing an issue is where the floor is scrubbed several time daily with a sweeper scrubber unit (Tennant), the frequency of which increased dramatically in the last two years. Bi-weekly the plant also polishes the aisles with a diamond pad. Could the metal hardener be getting water (no urethane concrete sealer anymore due to the polishing) and more water at the joints and causing the metal hardener to corrode thus creating the spalls? Does this warrant a core/petrography to see if this is occuring? Would a rigid epoxy mortar repair be a suggested solution after sawcutting and removing 1/2" to 3/4" of the spalling material, then re-establishing the joint with a sawcut and filling with a polyurea?
Final Update: I will likely go with the following repair method:
http://metzgermcguire.com/wp-content/uploads/2012/02/AH-Joint-Rebuild-2013.pdf1. Sawcut damage limits behind spalls
2. Chip out damaged/spalling material
3. Clean and prime the joint area
4. Fill the joint with Armor-Hard material
5. Trowel flush, cure
6. Flush grind surface
7. Sawcut new joint over location of the old joint
8. Fill new joint with polyurea
Thanks for everyone's input.
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Thomas Halmi P.E., M.ASCE
Senior Facilities Engineer
Steelcase
Belmont MI
(616) 866-8863
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