Dark grey water spot in new concrete floor

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kdrymer

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Hello all - I had a concrete floor poured in my garage a little over two weeks ago. The floor came out great, however I noticed one small spot the other day that is a dark grey color. I had used my pressure washer a couple days ago and this is normally the spot I store it in the garage. I think a little bit of water dripped out of the pressure washer wand and got on the floor. I had the garage closed for the last couple days and I believe the water didn't really evaporate.

I tried cleaning it with a mild concrete cleaner and warm water but it appears to still be there. It is definitely not motor oil or any other kind of stain. Is this something that will fade over time? I assume because the water was puddled in this spot that it affected how the concrete was curing and caused the discoloration, but I'm hoping someone can clarify if this is probably the case. I attached a couple pictures for reference. Thanks in advance!

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Concrete and cement are porous materials and you may have had a small puddle absorb into that spot. It should dissipate in a day or two without any harm. If you did not have a damp spot there before the resurfacing, it is highly unlikely that it was caused by the resurfacing. Two weeks seems like plenty of time for the floor to cure, so it should not weaken the bond there.
 
Thanks - I know I'm probably being OCD about it. I'll update in a couple days whether it fades back to the original color or not. I didn't realize a small puddle of water left on the floor would affect the color two weeks after pouring, but I know it takes about a month to fully cure.
 
Thanks - I know I'm probably being OCD about it. I'll update in a couple days whether it fades back to the original color or not. I didn't realize a small puddle of water left on the floor would affect the color two weeks after pouring, but I know it takes about a month to fully cure.

Concrete is porous so water will soak into it.
 
It has definitely faded in the last week, may be hard to tell in the picture though.

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UPDATE: It's been just over a month since the slab was poured in my garage. As I was emptying out the garage to have the contractor come and put the concrete sealer down I noticed another area where I had placed my Kayaks on that was extremely dark in color. This spot is in a corner of the garage so I'm wondering if the kayaks sitting on the floor somehow prevented the concrete from evaporating any moisture as it was still curing. I'm going to leave the kayaks in another location for a few days but wondered if anyone knew what this may be and if I should just give it a few months to even out? The dealer has been applied now so hopefully that doesn't interfere. I've heard that applying vinegar helps dry up concrete but want to wait a while before having to try something like that. I posted a picture similar but not the exact spot where the kayaks were stored.

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