concrete bonding adhesive

[AskTooMuch]

I'm reviewing a drawing where a new pedestal just 2 feet in height, 1.5' sqaure, is connecting to an existing slab on grade. Horizontal shear on pedestal is less than 3 kips. Drawing is asking to roughen existing and use bonding adhesive. Pedestal rebar will be doweled in using hilti epoxy. The use of bonding adhesive the I want to question in this case.

In case of new spread footing, pedestal is poured after footing hardens but no bonding adhesive is used.

 

[KootK]

Like you, I see the bonding adhesive as likely unnecessary.

 

[EDub24]

In my opinion bonding adhesive is unecessary. As long as the surface is properly roughened, cleaned and has a saturated surface dry condition prior to placing the new concrete then you’re ok. Too many times I’ve seen contractors put the bonding compound on and then wait to place the concrete. The compound cures and you now have a bonafide bond breaker.