Materials - Glass and Plaster
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Global Summary Building Summary Design Options Materials Stone Glass and Plaster Metals Earth Wood Strawbale Planted Roofs Ventilation Energy Savings Building Config. Room Layout Solar Orientaion Cooling/Heating Water Heaters Water Conservation Landscaping Rainwater Waste Water Readings Examples
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Glass consists of silica (sand), sodium oxide (soda), and calcium oxide
(limestone), with mineral oxides, colourants, and cullet (broken glass).
These are melted a temperatures of more than 1500c, shaped, and then cooled
to prevent crystallisation and cracking.
Lime plaster is a compound of slaked lime and sharp, coarse sand mixed with water; fibrous materials, such as animal hair, provide extra binding. Plaster of paris is produced by heating and grinding gypsum (calcium sulphate) and mixing it with water, while Portland cement is made from lime and clay, which, when mixed with aggregate, such as sand or gravel, makes mortar and concrete. Glass and plaster are both made from abundant, natural resources. They are healthy and nonpolluting, and while glass is an inert material, natural plasters have good breathing qualities. Glass is a poor thermal and noise insulator unless it is double or triple glazed or has a lowemissivity coating. Water and frost action causes exterior plasters to crack and badly polluted air discolours them. Extraction and manufacturing processes can disfigure the environment and glass production consumes vast amounts of energy (embodied costs), as well as creating combustion pollution. On the positive side, glass is easily reused and recycled, but all too often glass bottles and jars are simply discarded. |
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