3. The conventional and unconventional materials used
All construction material is manufactured from a combination of raw materials that involve energy expenditure and associated waste. Therefore, the energy cost of manufacturing building mate-rials is an essential element in computing environmental impact,and manufacture is probably the element most widely cited when considering the environmental impact of construction materials.This analysis raises typical questions such as: Are the raw materials renewable? Are they scarce? Are they important to the global environment? How much energy is required and how much waste is produced in the manufacture? What impact does this waste have on the environment?. The construction process also involves energy expenditure and produces waste, and also poses more important questions: How much manufactured material is used?Can materials that cause less environmental impact be deployed?How much energy is used? How much waste is produced? What is the environmental impact of the waste? Such questions can only be answered according to the specific structure to which they are applied. Increasing attention is now being given to the construction phase as part of efforts to make construction more sustainable.