The potential use of alternatives to primary aggregates in coastal and river engineering

This paper reports on a recent CIRIA study, carried out in collaboration with HR Wallingford, to assess the potential for using recycled/re-used (secondary) aggregate and construction and demolition waste as aggregate for coastal and river engineering. The objectives were to: • Reduce the impact of river and coastal construction on natural resources by promoting the use of alternative materials in place of primary aggregate and other materials. • Enable the construction industry to provide more sustainable and cost-effective solutions for river and coastal engineering. • Raise awareness of the potential use of secondary aggregate and recycled/reused materials as aggregate. • Reassure designers and constructors of the appropriateness for use of alternatives to aggregates. • Help overcome barriers to the use of alternatives to aggregates in a strategic and co-ordinated way. • Produce a best practice guide on the above. The demand from coastal and river engineering works for primary aggregate is increasing and is expected to expand further. It is recognised that this demand will need to be met, in part, by alternatively sourced aggregate. This paper reviews the availability of secondary and waste materials for application to river and coastal engineering and how designers and engineers can apply them.