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aggregates
aggregates Aggregates are particles of rock that are used in bound or unbound form as construction material. They consist of particulate rocks that vary in size from sand to pebbles and cobbles. There are two major types of aggregate: natural and processed. Natural aggregates are mostly derived from unconsolidated glacial, river, and marine sand and gravel deposits, which are primarily of Quaternary age. They are quarried from surface and subsurface deposits, dug from river and beach deposits, and dredged from offshore sediments. Natural aggregates need minimal processing, such as separation into appropriate grades, to produce the end-use material. Processed aggregates are derived from stone, which is quarried or mined and is then crushed to provide the grade required. Crushed aggregates are generally coarse, consisting of rock particles with a diameter of more than 5 mm. They are typically produced from limestone, crystalline rocks (including granite and dolerite), and sandstones. By-products such as blast-furnace slag, broken rubble, and pulverized fly ash from power stations are also used as aggregates. Aggregates are of high economic importance, representing the greatest volume of any geological material extracted in most countries. They are used in the construction industry, either alone or as additives to cement to form concrete.
K. Vala Ragnarsdottir Bibliography Bennett, M. R. and and Doyle, P. (1997) Environmental geology: geology and the human environment. John Wiley and Sons, Chichester. |
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PAUL HANCOCK and BRIAN J. SKINNER. "aggregates." The Oxford Companion to the Earth. 2000. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. PAUL HANCOCK and BRIAN J. SKINNER. "aggregates." The Oxford Companion to the Earth. 2000. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O112-aggregates.html PAUL HANCOCK and BRIAN J. SKINNER. "aggregates." The Oxford Companion to the Earth. 2000. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O112-aggregates.html |
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Aggregates
Aggregates. See skandha.
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Cite this article
DAMIEN KEOWN. "Aggregates." A Dictionary of Buddhism. 2004. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. DAMIEN KEOWN. "Aggregates." A Dictionary of Buddhism. 2004. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O108-Aggregates.html DAMIEN KEOWN. "Aggregates." A Dictionary of Buddhism. 2004. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O108-Aggregates.html |
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