Concrete and patio Stain Identification

I just did a 5500 sqft pebble driveway cleaning + some rust stain removal and cleaning on the patios out back. The apron of the driveways had these weird acid stains. I didn’t say I would remove the stains but I am curious as to what they were and if you were to remove them how would you do it?

I also powerwashed the front and back patios. Did some rust stain removal on the back but I used no chemicals on the front. I came back to take some after pictures and there are some new brown stains on the patio. You can see them right beside my right foot in the bottom photo. They were not there before. She hasn’t mentioned them yet but I want to get ahead of it and see what the fellas think. I’ve looked around the forum but haven’t found a stain quite like the one on the apron or the brown marks on the patio.
Thanks for the help fellas.

For refernce here is an after picture of the apron. Its cleaner but still stained

Stain on porch is where dirt leaked out from under columns probably. You need to learn how to rinse. The debris isn’t even pushed back off the sides at apron at bottom. And you never leave dirt and crap at bottom of drive in the street, otherwise when they drive over it going to track right back up… Rinse out cracks on drive when you clean. That’s a terrible job. If mine you wouldn’t have gotten paid. Sorry, but being bluntly honest here. Never leave a job looking like that. If you have dirt and mulch running back over drive, cut small channel along edge of drive and then when it’s mostly drive and you post treat, even with your hw mix, you can use edge of your fan spray and cut in lightly along edge of drive and it won’t run back over.

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I agree with you 100% and thankfully this isnt the full story. I spent probably too much time rinsing the dirt from this driveway away from the apron and entrance because there is a 10x8 splotch of gravel outside of the frame of the picture smack dab in the middle of the street. The city had to do some work and I guess they havent gotten around to repaving. There’s tons of clay on the street from construction two doors down and they havent been able to stop it because of the rain. As far as the cracks on the apron you can see there is some expansion foam in the bottom that matches the driveway. A good bit of it was already gone but I tried to not remove all of it and that means not directly spraying the cracks. I’ve not done much research on it but I always err on the side of caution. Much rather leave something a little dirty than damage it.

This was also 4 days after the fact and we’ve had rain the whole time. First chance I was able to grab after pictures because it was finally dry. I also finished this driveway in the rain and came back that evening to post treat once it was dried.

anyway do you know what those stains are?

Second pic looks a little better. Re foam, just fan rinse those cracks if you have to, kind of like rinsing trash out of window sills. Those stains just look like something leeching out of the cracks to me.

The stains on the concrete apron are acid burns. To achieve the pee gravel or wash rock look, on the driveway, the final step of the process is to acid wash the exposed aggregate or stone.


Thank you. I wasn’t sure if you were still around but you got the concrete bat signal.

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