We have an occasional need to do sieve analysis of crushed rock where I work. I have a sieve shaker but need a method of drying the samples. Where the shaker is set up I don't have the adequate wiring that is needed to put in an oven.
I have seen pictures of a drying table used for this...
Check out the following links, it might give you some ideas:
http://www.fahrindustries.com/Low_Volume_Roads.html
http://www.terex.com/main.php?obj=prod&action=VIEW&id=9dcb874ca6679e1f8bc8c395336dc2b5&nav=prod&cid=e75ed9c85681b27ffcfe5cadbd68c04e
I have dealt with a lot of that working in the forest industry in the Pacific Northwest. The rock used in your roads is probably pretty low quality in terms of hardness. Most likely something they could dig directly out of a pit with an excavator as opposed to something that needed to be...
