Aggregates are the world's most widely-used resource after water and it is important to consider their use in the context of sustainable development, which may be defined as development that meets the needs of the present without compromising the ability of future generations to meet their own needs. The assessment of a sustainable approach to the development of aggregates requires consideration of social, economic and environmental factors and balancing the various effects. This may be expanded to a life cycle approach in which the extraction, production, distribution and utilisation, together with the consequential energy consumption, pollutants and wastes, are taken into account. This methodology provides a way of comparing various strategies and quantifying the impacts and benefits so that the most sustainable way of developing, using and re-using resources can be selected. All types of aggregate are considered - crushed rock, sand and gravel, artificial, secondary and recycled - in terms of resources, manufacturing, distribution, markets, consumption and recycling. These are set against the various constraints of finance, cost, competition policy, planning, environment and specifications. It is concluded that: the development of sources of primary aggregates should take into account a life cycle assessment of the impact of this action; this development should be considered in a broad perspective, possibly on a regional scale; a change from conventional compositional specification to performance-based specification, concentrating on fitness-for-purpose, should reduce the demand for primary aggregates. In addition, ways of minimizing the environmental impact of planning and the associated transport movements should be developed. Also, materials of known performance characteristics, using materials other than primary aggregates, should be developed and ways of dealing with pollutant-bearing secondary materials and wastes should be investigated. For the covering abstract see ITRD E118727.
Samenvatting