Bonded Floor Slab (meaning concrete slab with a concrete overlay)

[PT999]

I am looking for design guides, or codes, on how to design a bonded floor slab. Anybody know anything about this?

This is a follow-up on my thread for concrete floor slab analysis, designed to support bus and truck lifting machines (with wheels that are so small, they overstress a standard slab).

Apparently bonded floor slabs are common throughout Europe where this lifting machine is in regular use.

 

[Lutfi]

Are you speaking in terms of electrically bonded? Or other type of bonded as in using bonding agents?

Please elaborate.

 

[SlideRuleEra]

I have used both bonded and unbonded overlays for industrial applications. For bonded overlays there are many proprietary products that help "glue" the two layers together. However if the base concrete is lightly scabbled, thoroghly cleaned and presoaked with water, the bond is probably just as good, or better, than with purchased bonding agents.

Here is a link to a short US Army Corps of Engineers document on the subject (see Chapter 11):

http://www.usace.army.mil/publications/eng-manuals/em1110-3-135/toc.htm

This document does not mention presoaking with water - however if you can do this (overnight or longer) before placing the overlay, it makes a significant contribution to the bond strength.

 

[SlideRuleEra]

Oh yes - Here is the Corps of Engineer's overlay design document (see Chapter 5):

http://www.usace.army.mil/publications/eng-manuals/em1110-3-142/toc.htm

 

[jheidt2543]

The August issue of "Structural Engineer" magazine has a feature article entitled "Bonded Concrete Toppings" on pages 44 - 49. The article discusses toppings on precast concrete, but is certainly applicable to toppings on other concrete slabs too.

I agree with SlideRuleEra's comments. Shot blasting or scabbleing provide the roughness, but cleaning of any coatings or oils on the floor is very important. We have used epoxy and latex bonding products as well as a cement/sand slurry.

 

[PT999]

Thanks Lutfi
How the layers will get bonded I have to find out, but not electrically.