Naji Khoury, an Assistant Professor at Temple University in Philadelphia, has developed a cement-like material, called "Plastisoil", made from discarded polyethylene terephthalate (PET) plastic bottles which is mixed with soil. The mixture is then blended with a coarse aggregate and heated. The result is a hard yet non-watertight substance, similar to porous asphalt.

With traditional concrete and asphalt paving, rainwater stays on the surface and runs into the stormwater drains. With Plastisoil, water is able pass through the paving into the soil below. This reduces the amount of pollutants entering waterways.

Professor Khoury says that it takes less energy to produce one tonne of Plastisoil than one tonne of cement or asphalt.