I am getting ready to bust up my old concrete driveway and use the "urbanite" to create pathways and such. My question is...what should I use to replace the concrete? It is a double driveway in Central Phoenix in a historic neighborhood. I am lazy when it comes to removing weeds so I would like something that is impermeable to them. I do not know anything about asphalt or gravel or any other substrate. I do not want to replace with concrete. Happy to take any suggestions. Thanks!