New Bonded Topping on Old Suspended Slab Floor - are control joints required

[ajk1]

For a new 2½" thick unreinforced concrete bonded topping (on an approximately 100 foot x 125 foot floor area), to be placed on an old reinforced concrete suspended slab floor, should control joints be provided in the new topping?

The topping will be covered by a hot-applied rubberized asphalt waterproofing membrane which in turn will be overlaid by a 1" thick mastic asphalt traffic topping. There will be no reinforcement and no mesh in the topping. The old concrete slab will be prepared by shotblast and a proprietary water based epoxy bonding agent applied just ahead of the concrete.

Since control joints are intended to allow movement, and since the slab is intended to be bonded and not allow movement, I am not sure control joints will accomplish anything.

 

[KootK]

I vote for no control joints. Same reasoning as you've stated.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[SlideRuleEra]

Match the joint in the existing slab. If there are none in the existing slab, don't put any in the topping.

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[hokie66]

A suspended slab doesn't have "control joints", so neither should a bonded topping. The topping will work compositely with the underlying structure, so you don't want discontinuities.

 

[ajk1]

ok, thanks everyone. Much appreciated.