Bonded Concrete Topping Spec

[KarlT]

Does anybody have a good reference for bonded concrete topping specs (slab preparation, topping mix, placing, finishing and curing?)

We want to put together one for use on our projects, and our master spec is pretty skimpy on that topic.

 

[jheidt2543]

For the most current information I would suggest contacting your local reps for Sika Corp. and Master Builders. They are two companies on the cutting edge and both have a willingness to share their information with prospective clients.

 

[JAE]

ACI 325 is for bonded overlays on pavements which may not be exactly what you're looking for.

http://www.concrete.org/BOOKSTORE/BKSTR.ASP

You could try looking throughout ACI for other info.

We have some notes/specs we've used before - I would have to look for them at the office on Monday -

 

[KarlT]

Thanks guys, anything info you might have is appreciated.

I'm actually considering writing a spec mainly for bonded toppings on existing concrete slabs, with interior conditions.

We got into a situation recently in which we referenced the Cdn concrete code (A23.1), which in our opinion is adequate to guide all contractors towards placing a bonded topping properly.

The contractor ended up subcontracting the topping project to some sidewalk contractor to didn't have a clue about how to place a bonded topping. (The pump broke down early in the pour, the concrete wasn't tested, the bonding agent most likely dried out by the time they placed the concrete, they didn't cure the topping properly, and guess what....the topping all delaminated)

Our client feels we need to hold the contractor's hand with bonded toppings on all future jobs, so hence the spec. I'm not an expert in this area so I thought I'd test the waters to see if anyone out there has some helpful info.

Thanks again!

 

[CarlB]

You might check

http://des.od.nih.gov/eWeb/construction/pdf/TOC_Specs/Division-03/03532-New01.pdf

as an example spec section.

 

[jheidt2543]

I don't mean to be too harsh or presumptuous, BUT:

1. Referencing a building code as a specification is never a good idea. They rarely cover the topic and when they do, they are only minimum requirements.

2. If you don't know how something is supposed to work, how can you write a spec for a contractor to follow? We can't know everything, so I try to find the best information possible before hand. Firms like Master Builders and Sika have sample specifications that cover this topic (no pun intended).

3. Even if he's the low bidder, if a contractor hasn't done it before, it spells TROUBLE. For processes you haven't been through before, insist on people with experiance, the added cost is worth it.

 

[KarlT]

Ouch!

Ok, Ok, I agree the code only covers the minimum requirements. I just wanted to make sure that whatever I do come up with will work, but will also be practical from a contractor's point of view.

I never thought of Sika, or Master Builders - good idea.

PS - The contractor basically did the topping without contacting us during any of the stages, so unfortunately we were totally left out of the loop....

 

[jheidt2543]

KarlT,

The other good thing about firms like Sika, Master Builders, W.R. Grace, Sonnoborne and W.R. Meadows is that they have field reps. that will come to the jobsite for the first day of a project and help supervise the intial installation. That can get everyone off on the right foot.
Just another thought.

By the way, I have read a number of your posts on the forums and respect your opinions.

 

[KarlT]

jheidt2543

Thanks for your advice and also your reassurance - that's the nice thing about this site, it's like having a room full of engineers with unlimited experience to tap into any time day or night.

The more I research about bonded toppings, the more i realize there are a dozen different ways of screwing it up. It certainly isn't as easy as it may seem.... My guess is that debonded toppings have provided lawyers with lots of extra cases to work on!

 

[DRC1]

I have used the Sika product for topping stairs and platforms with very good results. I don't know about other products but suspect Master Builder W. R. Grace and Sonneborne have similar products. I would find 2 or three products that you like for the application, and have the contractor select a product, submit a manufacture's spec and application procedure prior to doing the work, and if it is a large enough job, have the rep come out.
Talk to the technical departments for the products you like prior to including them in the bid documents so you are sure the manufacterer wont tell you his product is not suitible for that application after the contractor selects it from the approved list. (Talk to the tech depart., not sales.)
The problem with trying to write a spec is that each product is somewhat different in its application proceedure and you don't want to be in the situation where your spec says one thing and the manufacterer says some thing different.
Good Luck!

 

[jheidt2543]

I should add another thought, surface preparation is a real key element in using any of the products for topping bonding. Basically, there are two methods, chemical and mechanical. Chemical preparation is some type of acid etching using diluted solutions of hydrocloric or fosforic acid. Mechanical preparation is done with a shot blasting or terrazzo grinder.

There are advantages and disadvantages to both methods, particularly when it comes to the disposal of the residue materials. Be sure to discuss this with the product reps and the contractor that does the work.