Environmental assessment of secondary construction materials

Abstract: Process industry, construction and other comparable activities produce large quantities of waste with potential use in geotechnical applications. Prior to utilisation, an acceptably low risk of contamination to humans and the environment must be demonstrated. This work focuses on the identification and evaluation of critical factors for environmental assessments of secondary construction materials. The market potential and the main barriers for usage of industrial wastes were analysed and showed a good potential especially in urban areas. The main obstacle is the long and complicated permit process involved. Further, the lack of a general procedure to investigate the suitability of intended usage leads to inconsistent assessments. An evaluation of leachate emissions from a large-scale test road demonstrated the importance of construction design and site-specific field conditions on the potential environmental impacts. It was also shown that pollutant concentrations in leachate from secondary construction materials tend to become comparable, or for some pollutants, even lower than from rock materials. Different assessment methods and criteria to judge the acceptability of an intended use were reviewed and various methods were identified. However, a generic method to evaluate materials under various environmental conditions is lacking.