Good looking gravel on big surface?

I have a issue today (among many others ;)) that if I render a view the gravel becomes to look like a carpet.

Anybody that has any ideas on this? The material should be looking good independent of the view distance, so it should look good on close-ups and from far away. For fine materials as concrete it's not an issue, but when it comes to more coarse materials like this gravel it harder.