Chapter 76 Issues for pavement design

There have been significant developments in the design of pavements and trackbed for roads and railways in recent years. Latest design specifications take a more rational approach than the traditional recipe method based on experience, and offer potential rewards including the wider use of more sustainable marginal materials and reduction in construction thicknesses. Pavement design involves significant geotechnical engineering and the latest specifications place even greater importance on the assessment and selection of appropriate materials for the ground conditions present. This chapter gives a brief outline of good current design practice for UK roads and railways, and references are given to some of the key literature available for further reading. The focus is on the design methods developed for motorways and trunk roads (produced by the Highways Agency) and railways (Network Rail) as the majority of research carried out in the UK has been related to these. The importance of the assessment of the sub-grade and development of a design which suits the ground conditions present is emphasised.