Route planning and avoiding gravel/unpaved roads? I've got a Garmin Edge 810. Sometimes when using routes created with Garmin Connect or Strava Route Builder, I unfortunately find myself on bad gravel roads.

Is there a route planning tool that allows you to only select asphalt/tarmac?
Use Bike Route Toaster and make sure you are using Open Street Maps Cycling version ("Open Cycle Map).  As part of the route finding options under Open Street Maps there is an "Avoid unpaved roads/paths"



I have successfully used Bike Route Toaster with a Garmin 800 in the past.  I planned out a 1000 km journey across Norway on back roads, gravel (eek!) and paths.  It was amazing how well it worked, thanks to the all the hard effort of volunteers around the world who contribute to the cycling version of open street maps.  I only had one minor hiccup in all those miles. 

Good luck!