ALL ABOUT ASPHALT Did you know that asphalt was used in ancient times? Asphalt is a dark brown to black mineral substance found in the earth in liquid, solid, and partly solid forms. It's also a natural part of most crude oils and is not to be confused with tar; which comes from coal. Asphalt softens when warmed. It becomes liquid when heated, and then hardens when cooled. Chemically, asphalt is a combination of hydrogen and carbon. Some of the ancient uses of asphalt included: -According to the Bible, used in Noah's Ark -Preservation for mummies -Asphalt is the world's oldest cementing material and used in the ancient eastern Mediterranean countries for their buildings. -Waterproofing pitch on ship hulls -The basket in which Moses floated down the Nile was made waterproof with asphalt -Columbus used asphalt to caulk his ships. The asphalt came from Trinidad's famous Asphalt Lake In modern times asphalt is used primarily to pave roads. -Asphalt was used in 1876 to pave Pennsylvania Avenue Washington, DC -Today 9/10 of all paved roads and streets in the US are surfaced with asphalt, that's almost 2 million miles -Asphalt pavement is the most recycled product in the United States at 80 percent Composition and Uses of Asphalt Ingredients 1. Aggregate a. Sand b. Rock 2. Asphalt a. Liquid holds aggregate together and waterproofs Construction 1. Sub Base a. Compacted Soil 2. Base a. Crushed Rock 3. Asphalt Binder 4. Asphalt Topping Major Causes of Asphalt Deterioration 1. Sunlight or Oxidation- Breaks down and dries out asphalt causing traveling and shrinkage cracks. 2. Water, Ice and Snow- Penetrates asphalt surface causing heaving and base deterioration. 3. Gas, Oil, and Chemical Spillages- Causes soft spots in asphalt surface and eventual erosion to base. 4. Poor Construction- not enough Base or Asphalt or poor asphalt mix.