With five portable asphalt plants, Riverside has the capacity to pave multiple projects at one time. Asphalt is made by mixing aggregates with a petroleum-based binder. Oftentimes, our asphalt mix also incorporates reclaimed asphalt pavement, or RAP, which is old, worn-out roadway that is milled up and crushed into a reusable product. Mix designs containing RAP help us minimize waste and conserve natural resources.