Austroads has published an updated edition of Guide to Pavement Technology Part 4K, a guide to the procedures for the selection and design of sprayed seals.
Sprayed seals are an important component in the road system in Australia and New Zealand.
Much of Australia is sparsely populated with large distances between centres of population. Providing a network of sealed roads has necessitated the development of outstanding skills in low-cost road construction and maintenance techniques, particularly the use of thin sprayed bituminous treatments on pavements constructed from locally available materials (often of marginal quality) or crushed rock.
Similarly, in New Zealand, a relatively small population base has driven the need for low-cost road building.
This is an update of previous Austroads procedures based on the philosophy of filling up voids in the aggregate matrix with binder, to a depth of about one half to two thirds the height of the aggregate when laying on its least dimension.
The Guide discusses the historical background and operational environment of sprayed seals, alongside design, selection and construction procedures for various types of sprayed seals.
The Guide was previously published as Guide to Pavement Technology Part 4K: Seals. This new edition of the Guide has been restructured and content updated to improve overall readability and usability, and incorporates sprayed seal design, which was previously published in a separate document.
The terminology used to describe sprayed seal treatment types has been updated, with some name substitutions and additions, and inclusion of different material usage based on the findings of recent Austroads studies. New information for selecting sprayed seals is included. Various updates to design parameters have been updated to reflect current practice.
The Guide was authored by Steve Patrick from ARRB and the project to update the Guide was managed by John Esnouf from VicRoads.
PDF versions of the Guides are available to download for free.