Aggregates and water are from natural resources, only cement must be produced in fabrics, processes which are polluted the environment (for producing 1 m 3 of concrete a quantity of 480 kg of CO 2 is liberated in the atmosphere). Usually, ordinary concrete contains about 12% cement, 8% water and 80% aggregates by mass. The new generation of building materials is developing on other theories in concordance with the sustainability of environment.Ĭoncrete is obtained from natural aggregates, cement and water, compounds which make it a cheap material and easy to produce anywhere. The building material industry is a domain of interest for using the wastes and researchers have tried to produce new construction materials incorporating wastes. The construction and the building materials sectors are involved in both processes: building industry is the largest user of natural materials and in addition a large amount of wastes results from the demolition of constructions. Lately, the environmental sustainability became an important problem from the point of view of natural resources and that of wastes.
The capitalization of waste is difficult because of their variety, as well as their unknown properties over time. The wastes represent a major problem for the environment because the air pollution (the dust and very fine particles which spread in the atmosphere) and leaching toxic chemicals (arsenic, beryllium, boron, cadmium, cobalt, lead, manganese, mercury, molybdenum, selenium, strontium, thallium, hydrocarbon compounds, etc.) when are dumped in landfills, quarries, rivers or oceans. These industrial and agricultural wastes are by-products, slag, rice husk ash, bagasse, fly ash, cement dust, brick dust, sludge, glass, tires, etc. The problem of waste accumulation every year is all over the world. In the last decades, due to the modern lifestyle, the progresses in industry and technology had led to an important increase in the amount and type of wastes.
0 kommentar(er)
