The idea is to use an abundant resource – sand – and to mix the sand with a solution containing the microbe Bacillus Pasteurii, which cements the sand into a biologically engineered hardened sandstone. Then the sand-and-microbe solution is sprayed onto a layer of sand underneath and hardens the whole thing into a tough road surface made of bio-sandstone.
This process eliminates using asphalt, which requires large amounts of oil to create, and eliminates heat islands caused by asphalt as well.