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Titel:
Characterization of the leaching behaviour of cement mortars to assess long term environmental behavour during their service life and their recycling stage
 
Auteur(s):
 
Gepubliceerd door: Publicatie datum:
ECN 1-7-1998
 
ECN publicatienummer: Publicatie type:
ECN-RX--98-026 Artikel wetenschap tijdschrift
 
Aantal pagina's:
22  

Gepubliceerd in: Submitted to the Journal of Cement and Concrete Research (), , , Vol., p.-.

Samenvatting:
The environmental properties of the cement mortars m their service lifeas well as in the secondary life (construction debris) is raised as an issue of concern in relation to die use of alternative fuels and raw materials m the production of cement clinker. A comparison of the leaching behaviour of cement mortars from natural materials and such special cements has shown that the leachability of cement mortars from special cements does not exceed the leachability from traditional cements. For crucial constituents, such as Cr, even a lower leachability is observed in spite of a higher total composition. This illustrates that an evaluation of cement mortars based on total composition is not a valid means of judging environmental impact. The emphasis in environmental evaluation has been on the service life of cement-based products. This stage of life of a cement-product proves to be of very limited concern. The emphasis should be focused m the 'second life' of cement mortars. If construction debris is reused as aggregate m cement mortar, again leachability is of limited concern as the chemical environment dictated by the cement mortar ensures a low leachability. When construction debris are reused as aggregate, e.g. in road stabilization, environmental issues prove to be relevant as oxy-anionic species (e.g chromate, sulphate, molybdate, vanadate) may exceed critical limits. With the possible exception of Cd, metals such as Pb and Zn are unlikely to become critical environmentally, even in the 'second life' of cement mortars. New environmental criteria for cement products should be developed based on leachability. 27 refs.


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