20.06.2010 // æs.fɒlt
Interesting facts:
• The word asphalt is derived from the late Middle English : from French asphalte, based on Late Latin asphalton, asphaltum, from the Greek ásphalton, ásphaltos (άσφαλτος), a word of uncertain origin meaning "asphalt/bitumen/pitch" which some derive from α- "without" and σφάλλω "to make fall".
• Natural deposits of asphalt include lake asphalts (primarily from the Pitch Lake in Trinidad and Tobago and Lake Bermudez in Venezuela), Gilsonite, the Dead Sea, and Tar Sands. Asphalt was mined at Ritchie Mines in Macfarlan in Ritchie County, West Virginia in the United States from 1852 to 1873.
• In the ancient Middle East, natural asphalt deposits were used for mortar between bricks and stones, to cement parts of carvings, such as eyes, into place, for ship caulking, and for waterproofing.
• The first use of asphaltum in the New World was by indigenous tribes. On the west coast, as early as the 13th century, the Tongva and Chumash Nations collected the naturally occurring asphaltum that seeped to the surface above underlying petroleum deposits. Both tribes used the substance as an adhesive. It is found on many different artifacts of tools and ceremonial items. For example, it was used on rattles to adhere gourds or turtle shells to rattle handles. It was also used in decorations. Small round shell beads were often set in asphatum to provide decorations. It was used as a sealant on baskets to make them water tight for carrying water. Asphaltum was used also to seal the planks on ocean-going canoes.
• Asphalt is typically stored and transported at temperatures around 150 degrees Celsius (300 °F). Sometimes diesel oil or kerosene are mixed in before shipping to retain liquidity; upon delivery, these lighter materials are separated out of the mixture. This mixture is often called bitumen feedstock, or BFS.
Sursa
2010-10-13 02:02:00