Orange rust spots one driveway

Hey there,
I was wondering what exactly causes those orange rust spots to appear on someone's driveway and what can be done to prevent it?

It's rust of reinforcing in concrete (concrete cancer) it's caused when the reinforcing steel has inadequate cover.
Prevention? Ensure adequate concrete cover.
Remedy? None.

Is it exposed aggregate? Does the stain come from small located spots?
If so, it's most likely some ironstone aggregate.
It's a naturally occurring formation in some rocks and sometimes odd little bits end up in the mix.
The staining itself can be removed with an iron stain remover but it will come back. If it's exposed aggregate you can locate the stone in the surface and remove it, then clean the stain.
Here is an explanation and resource that describes how to deal with it.
https://www.google.com/url?sa=t&source= ... 5zKGyTOgrH

If it's incorrectly placed reinforcement then you will have major problems going forward but most of the time it's what I've noted above.

Could also be as a result of fertilizer application, not sweeping granules off the concrete and those granules then getting wet.
Most lawn foods contain some iron sulphates

This happened to mine. Some simple bleach fixed the stains

Got to be on to it quickly though.
If the driveways isn't sealed and it has time to work it's way in it's there for good

Very common on rendered homes

Smaller suppliers get the lower quality raw materials