Green condos

CONCRETE IS GREEN

Environmental Benefits

• Low CO2 intensity - the production of concrete, which consists of 10% - 15% cement, results in emissions of about 0.13 tonne of CO2 per tonne of concrete, equal to 1/9 the emissions of cement. Concrete manufacturing results in less CO2 per unit than almost all other construction materials, making it the sustainable construction material of choice.

• Resource efficient - the ingredients for concrete - sand, gravel and limestone - are abundant worldwide. Quarries are readily reclaimed for recreation, residential or commercial development. They can also be restored to their natural state.

• Local resource - because the ingredients of concrete exist almost everywhere, concrete can be manufactured near a job site, requiring minimal energy for transportation. At least 60% of all concrete is made within 160 km of the job site. Wood and steel products, on the other hand, typically travel hundreds or even thousands of kilometres.

• Less construction waste - as concrete is manufactured to specifications, only the product that is required is delivered to the site. This means that less material is sent to landfill upon project completion.

• Reusable - many concrete products can be reused, such as concrete pavers and precast wall panels. Concrete sidewalk slabs are reused to build "dry stone" retaining walls. A well designed concrete building with long floor spans and column-free space is adaptable to a succession of different occupants.

• Recycling medium - Concrete makes waste products useful. Concrete is ideal as a medium for the inclusion of recycling waste or industrial byproducts such as blast-furnace slag (from steel making) and fly ash (from coal-burning electric plants). About a third of the fly ash produced annually in the U.S. is used in concrete. Use of such industrial by-products as Supplementary Cementing Materials (SCMs) to replace some of the cement in concrete mixtures also improves product performance for specific applications.

• New life for old concrete - Used concrete can be 100% recycled as aggregate for use in roadbeds or as a granular material. Concrete yields 45% to 80% coarse aggregate usable for new concrete mixtures. The rest can be crushed and re-used as base material for roadbeds, parking lots or other applications.

• Replenishes aquifers - Pervious concrete pavement and permeable interlocking concrete pavers can be used to reduce stormwater runoff and allow water to return to the water table.

Source : http://www.cement.ca/index.php/fr/Le_beton_et_l_environnement/Le_beton_et_l_environnement.html