Geotechnical specifications for sustainable infrastructure

The specification of the materials and methods used in earthworks and foundations for highways, railways and airfield runways can be approached in several ways. As a result of the sustainability agenda there is a need to use specifications that make best use of material properties, and a performance-based specification may be considered the best way to facilitate this. The functional requirements of a performance-based specification for UK highway foundations are considered. The (recently researched) performance-based specification for UK highway foundations is explained, demonstrating the steps to its development, determination of the engineering requirements, suitable target values and the potential construction-related implications. It is shown that performance-based specifications offer the advantage of better incorporation of the principles that underpin sustainable construction but also require a fuller understanding of material behaviour for their development and implementation. However, contractural issues and implications for construction need to be considered if a full performance-based approach is to be successfully adopted. It is considered in the UK that a staged implementation of a performance specification is necessary to permit the gaining of experience of both the process and the field measurement methods, some of which are relatively novel, and to reduce the risk of contractual disputes and thus a negative reaction from the industry. For the covering abstract see ITRD E145817