Expert: jonewall - 7/21/2010

Question
QUESTION: I recently built a home in NE Indiana where a drive was poured in early April We had abnormally cold temps that hovered above and below freezing during that period. I expressed my concern to contracter and was assured the proper additives would be placed in the mixture. I now have near the apron of our drive at least 20-30 black spots. I contacted the contracter who in turn contacted the mixing company. The rep from the mixing company indicated that there was no problem with concrete and was not sure what was causing issue. He said it might have been caused by finisher. When I mentioned this to contracter he said that it couldn't be from finishing. I'm not sure what caused these spots. It is not very appealing and it looks terrible. I wish I could go into more detail but these are spots that in some areas have shades of white in the center and around. I would be glad to send a few pictures.

Thanks
Dennis

ANSWER:     Dennis
will try to help

1. drive finished this April    possibly could be oil stains yes or no

2. stain location at beginning of pour or end of pour ?

3.shown up in area  ?????4feet ????? x  4 feet ??????

4.was there some type of additive in the concrete mix  ?????  calcium chloride  ( flak or liquid )

5. when did you notice spots    shortly after pour   or ?????????

6 are spots at surface    or slightly below ??????

7 best bet    have contractor ,supplier and general contractor at meeting
         a solution should have an answer      general contractor   1 year warranty ????????

8.send me pictures

9 can you dig out spot and see how deep,  sample of material to find out what it is ??????
don't do nothing  prior to meeting with all parties ,workmanship should be under a warranty

10.  I have written articles  check my site  www.chicagoconsultant.com

good luck

jon e

---------- FOLLOW-UP ----------

QUESTION: jon, thanks for the response and sorry in the delay of mine. I know this is not an oil stain.  The stains are at the end of the pour near the apron. Shown up in an area 10ft x 10 ft. Additives used were calcium, Air, Mr. Poxx NCA534 Limestone and sand. (hope this makes sense) Poured on4/8/10. Cold night 30-40mph winds. Spots noticed immediately the next day. Spots appear at surface. Contractor indicates no problem, Cement company indicated not their problem. I could only send one picture

Answer
Dennis
I'm disappointed that the supplier and concrete contractor with a visual could not give you a reasonable answer. was the concrete contractor a sub contractor or the general contractor? if a sub-contractor get both contractors together in meeting. Did you pay all the contract?
Something went afoul since the problem is not throughout the pour. Well some ideas for what it is worth ( without seeing )
Because of the cold was the slab covered ? What did they use canvas or possibly a straw covering with or without a cover on the slab direct? Are the spots in a pattern of spacing  so many inches apart ( maybe something like eyes in a tarp )
The last piece of the pour was 10' x 10'?  did that pour come in a new truck ) like a called in balance ) meaning a different batch of concrete ? is the finish appearance of the last part similar in color of the rest of the slab )color difference due to possibly different mixing of materials ,?)   Was the calcium chloride  used in flake or crystal, or liquid form ? That gets me back to spacing of spots.
Can you get any comments from your town building dept ?? Is the contractor union affiliated or licensed by town or state ??
I gather that you are in your new home and had a final inspection to occupy the house ??

We could go further maybe like did you hire the architect, sub-contractors or a general contractor on a lump sum contract. Suggest you read your contract agreement or ???
like warranty time etc  Hold backs on payments  The status of the contract terms are important
last but not least   Has the contractors good credentials ??? What is the total size of your CONCRETE  driveway?  

Well, here's hoping for your success
je