Asphalt is a combination of approximately 95% stone, sand, or gravel (aggregate), bound together by liquid asphalt, a crude oil product. The aggregate serves as the wearing course, and the liquid asphalt is the “glue” that holds it all together. Liquid asphalt is a solid at ambient temperature.
When heated to roughly 300 degrees, the liquid asphalt becomes liquid, allowing the aggregate and the liquid asphalt to be combined and mixed. This process is performed at an asphalt plant. The resulting asphalt is loaded into trucks for transport to the paving site.
The trucks dump the asphalt into the hopper located on the front of the paving machine. The asphalt is placed by the paving machine and then compacted using a heavy roller driven over the asphalt. Paving and compaction must be performed while the asphalt is sufficiently hot. Traffic is generally permitted on the asphalt.
