Asphalt

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Contents

Description

The dark, brownish-black bituminous resins occur naturally and are produced as byproducts of oil refineries. Ancient sources for asphalt include Egypt, the north end of the Dead Sea, the Is river northwest of Babylon, and the Greek island of Zante. Gilsonite is the hardest, most brittle variety. Some softer, more elastic varieties are Trinidad, Barbados, California, and Egyptian asphalts. They were often collected from pits or lakes and thus were sometimes called lake asphalts. Asphalts are soluble in oils and waxes and can act as a plasticizer or a strengthener depending on the hardness of the variety. They are composed of aliphatic, alicyclic and polycyclic aromatic hydrocarbons. Asphalts, under the name of asphaltum and bitumen, were also used as pigments to form a transparent brown film. Unfortunately, thick films with asphaltum often exhibit crawling, alligatoring, and disfigurement. In addition, asphalt was sometimes mixed with dry clay or limestone for use as an adhesive. Asphalt is used commercially for road paving, roof coating and joint sealing. It is also used as a waterproof barrier in sandy soils.

Synonyms and Related Terms

asphaltum; bitumen; Asphalt (Deut.); asfalto (Esp., Port.); asphalte (Fr.); asfalt (Ned., Pol., Sven.); asfalto (It); bitume (It); gilsonite; trinidad; barbados; bentonite; gum asphaltum; coal; coal-tar; anthracite; earth pitch; Trinidad pitch; mineral pitch; lake asphalt

Other Properties

Soluble in carbon disulfide, toluene, chloroform, ether, acetone, turpentine, naptha. Insoluble in water, ethanol, acids and alkalis.

Burns with a bright flame.

CAS 8025-42-4
Density 1.0 - 1.2
Refractive Index 1.635

Hazards and Safety

Combustible. Inhalation of fumes is toxic.

Additional Information

° Georgiana Languri, Molecular studies of Asphalt, Mummy and Kassel earth pigments, MOLART report 2004, available through Archetype Publications, London.

° Ancient Trade Routes: Website

Sources Checked for Data in Record

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  • The Dictionary of Paper, American Paper Institute, New York, Fourth Edition, 1980
  • The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 880
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  • CRC Handbook of Chemistry and Physics, Robert Weast (ed.), CRC Press, Boca Raton, Florida, v. 61, 1980 Comment: density=1.1-1.5; ref. index=1.635

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