Sustainable development and the cement and concrete industries.

摘要

Sustainable development is an attempt to mitigate the environmental damages of the past, to adjust the present exacerbated superfluous pattern of consumption and the increasing social gaps between nations, in order to provide the future generations a fairer society living in a more healthy environment.; Up to now climate changes has been the focus of the discussion, but sustainable development is a much more broader issue. Just 20% of the world population has a high standard of living and consumes the greatest part of energy and raw materials and as a consequence generates the majority of CO2 emissions, the main greenhouse responsible for climate change. At the same time, 50% of the population earns less than {dollar}2 US a day gasping for sanitation, hospitals, schools, houses just to satisfy the minimum of dignity.; In such a scenario the cement and concrete industries can play a key role either for solving social problems as for helping to mitigate the environment burden. Cement industry is often focused as a polluting industry, responsible for 6% of world CO2 emissions, and concrete is frequently presented as a low technological added value product that generates around 1 billion tonnes of wastes per year. This is a common unfair perception that reveals a lack of information and adequate analysis.; The cement industry experienced an extraordinary reduction in gas and dust emissions as well as energy saving rooted in significant technological investments in the seventies and eighties. Its CO2 emission is much lower than that of other industrial segments, such as transportation and progresses continue. At the same time millions of tonnes of industrial by-products and wastes generated by other industrial sectors are consumed and valorized by the cement and concrete industries every year.; As a construction material, concrete fulfils almost all the social and technological needs of societies. The spectrum of available concrete ranges from some MPa to 800 MPa, exhibiting high flowable properties or low noise when casting, showing good thermal performance at low cost, evidencing the immense technological progresses achieved in recent years.; With the current available technology a much longer life cycle of concrete structures should be achieved. An infrastructure lasting longer will contribute to reduce waste generation and alleviate budgets to invest in other social requirements instead of "indefinitely paying" for rebuilding or repairing structures in benefit primarily of contractors. (Abstract shortened by UMI.)