In the 20th century the primary use is in road construction , where it is used as the glue or binder mixed with aggregate particles or gravel to create asphalt concrete .
Some cities in California started asphalting their streets in the 1870s to keep down dust and mud .
In the 20th century the primary use is in road construction , where California is used as the glue or binder mixed with aggregate particles or gravel to create asphalt concrete .
Some cities in California started asphalting their streets in the 1870s to keep down dust and mud .