1- Granite
a) Composition: It is igneous rock. Its main constituent minerals are quartz, (hard and least affected by carbon dioxide and water) feldspar (crystalline, lustrous, readily attacked by atmospheric agencies) and mica (dark grey, black or brown in colour, soft, readily affected by chemicals and atmospheric agencies).
b) Characteristics:
• Its specific gravity is 2.64 and absorption less than 1%.
• It has mottled appearance.
• Significantly strong and durable.
• Finely grained granite takes a fine polish.
• Crushing strength varies from 110 to 140 MN/m2.
• It has least fire resistance as it cracks under a strong fire.
• Its colour depends upon that of feldspar.
c) Uses:
• Fine grained granite is suitable for ornamental columns, plinth, etc. as it takes a polish.
• Owing to the hardness, weight and durability of granite it is considered most suitable for the construction of sea walls, lighthouses, bridge piers, etc.
• Large pieces are used as building blocks, the smaller as road metals or railway ballast and the chippings for the manufacture of concrete or artificial stone.
2. Basalt or Trap
a) Composition: it is an igneous rock (siliceous variety). The main constituent are silica, alumina and feldspar.
b) Characteristics:
• Very hard and tough.
• Heavier than granite
• Has greenish grey to dark grey colour.
• Crushing. strength varies from 70 to 80 MN/m2.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
الرجوع الى لوحة التحكم
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