Finishing concrete after an overnight cure

[earlygl]

The crew showed up yesterday and did the dirt work and formed up for a 34 yard pour for my carport and driveway. At 3 o’clock in the afternoon the first concrete truck showed up and the last truck left at around 7:30pm. The finishers made the first skreet and smoothed it all out pretty good. They were waiting so they could start their power trowel and went as far as to place the machine on the concrete. Unbeknownst to me, as I am a police officer and had to go on duty, at this point they left the job. It was not until late the next morning that I found out my driveway was unfinished with gravel showing in spots. I called them and they told me they were on their way to finish it up. I thought his should have been completed last night but they told they would do it today. They arrived early afternoon and began roughing it with cinder blocks then they sprinkled it with Portland cement and began to power trowel it. They said they do this all the time and it will be just fine because the concrete is still green. Is there anyone that can shed some light on this procedure? It seems to me that the surface will not last due to poor adhesion. Thanks all, when I saw my drive I was the one that was GREEN. Gary

 

[Ron]

Absolutely unacceptable process! Reject the concrete and don't pay them.

The concrete must be finished while it is still in a plastic state. They are proposing to finish with a skim coat of neat cement paste which will crack and likely debond/scale.

Poor practice and not acceptable in any industry standard.

 

[hokie66]

Not that it needs to be said, but Ron is absolutely correct. If you can be more correct than absolutely, that too.

 

[earlygl]

Honestly I thought as much. I'm paying good money to get a professional job that I want to last. Thanks for the replys ya'll.

 

[TehMightyEngineer]

As a slight counter-point there is a way that this could work if they used a proper topping and procedure but it's 100% not as durable as doing it right the first way and absolutely not acceptable for new construction that clearly was their fault. Refuse payment and make them demolish it. There are ways it could be repaired but these are not going to be any cheaper than demolishing and rebuilding.

Professional and Structural Engineer (ME, NH)
American Concrete Industries

http://www.americanconcrete.com

 

[dicksewerrat]

If gravel was showing they also shorted the depth of concrete. Talk to some engineers that work for the same gov't you work for. One may volunteer to inspect the project as the next concrete placement happens. Makes not so good contractors into great ones.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[DETstru]

I would never accept something like this on a project.

Rule of thumb is that you must start the power trowel process when stepping on the concrete leaves a 1/8" boot print. They waited far beyond that. They let the bleed water and "watery cement" at the top cure, which will deteriorate and leave a weak layer of concrete that will dust over time.