NEW HIGHWAYS Agency design guidance is to allow contractors to use glass and industrial wastes in road pavements, officials confirmed this week.
The Highways Agency's Versatile Design Guide will mark the final switch to specification by performance rather than prescription.
It will allow contractors and designers to put forward almost any combination of natural or recycled aggregates and binders for testing and approval. This includes such materials as crushed glass and industrial wastes.
And for the first time design rules for fully flexible pavements and cement bound material/asphalt composites will be incorporated in the same document.
'It represents the latest thinking on analytical pavement design, ' John Williams, principal pavement engineer at the Agency, told NCE.
'One big change is that designers will be able to take advantage of good foundation conditions and use thinner construction.'
The new guide will be complemented by a special guide to the use of cold recycled materials in road pavements, which was launched at a seminar in Reading last week. This updates TRL report 386 and is again performance based.
'Experience and research has confirmed that cold recycled materials can be used successfully on nearly all trunk roads with the exception of the very busiest', said TRL pavement design team leader Ian Carswell.