THE ECOLOGICAL POSITION OF CEMENT AND CONCRETE

The global, regional and local environmental effects associated with t he use of cement and concrete are indicated and, as far as possible, q uantified to show the ecological position. The global and regional eff ects, such as energy consumption, greenhouse effect and acidification, are first determined for a cubic metre of concrete to obtain an ecoba lance. This takes into account the entire process chain, including all transport processes, from extraction of the raw materials for the cem ent and concrete, through the production of cement, and up to the mixe d and finished concrete. The general ecological significance of the pr oduction of building materials is then examined, and that of concrete is compared with other building materials, using examples of component s and structures. All told, concrete occupies an ecologically favourab le position as a building material, both in absolute terms and in rela tion to other building materials. The ambient pollution levels in the vicinity of production plants as well as the possible release of harmf ul substances from the building material are examined for their local effects on human beings and the natural environment. The ambient pollu tion caused by cement production is so low that in practice the ambien t pollution levels around cement works cannot be differentiated from t hose in equivalent areas with no industrial activity. Harmful substanc es such as heavy metals are only leached out of concrete in such small quantities that concrete can be used without hesitation even in the h ighly sensitive area of drinking water Gaseous emissions and radioacti ve radiation have no relevance for concrete. Taken as a whole, buildin g with cement and concrete is in all respects an environmentally compa tible method of construction.