Muriatic acid works great, etches the stone/cement.
Just be careful!
And check out this link for safety tips (note: the information on the back of the bottles syas very little about handling the product and disposal, etc.)
I have found muriatic acid can react with the gravel and sand in the concrete in interesting ways- including adding to the rust look where the gravel has a high iron content. I would test it on an inconspicuous area first.
There are many products on the market for concrete repair and refinishing, as well as concrete contractors who do it.
Epoxy based refinishing is popular. you can repair cracks, resurface the concrete in different designs,stamps, colors, etc.
The cheapest is epoxy-based paint by Quickrite available at home depot. you can repaint a driveway in a grey color for 3-400 bucks.
Keep in mind...if you paint the driveway, you now have an ongoing maintenance item.
Muriatic acid works great, etches the stone/cement.
Just be careful!
And check out this link for safety tips (note: the information on the back of the bottles syas very little about handling the product and disposal, etc.)
http://www.naturalhandyman.com/iip/infxtra/infmur.shtm
Good Luck
[addsig]
I have found muriatic acid can react with the gravel and sand in the concrete in interesting ways- including adding to the rust look where the gravel has a high iron content. I would test it on an inconspicuous area first.
Chris