[SG] asphalt bases

I'm basing my 15mm UN troops (hm, UN, KV, IF...I seem to take the Bad
Guys a lot) and am wondering how to get the effect of asphalt.	Righ
now I'm thinking to put on glue, then sand, then a glue/water mix over
top, then paint it black (with the occasional white or yellow lines
for pavement markings).  Any other ideas?