The original scientific analysis of chipseals and the development of a design methodology was by Hansen in the 1930s in New Zealand (NZ). This method was based on a single layer of a one sized chip. The basic concepts are still regarded by most sealing practitioners as valid and they have been adopted by many countries. This paper describes the evolution of the design methodology in NZ since the 1930s and the reasoning behind the latest revision. A comparison of application rates of binder used in NZ with Australia, South African and Texas methodologies is given. The significant changes in the viscosity of the cut back binder used for sealing that have occurred are also described. (a) For the covering entry of this conference, please see ITRD abstract no. E217100.
Samenvatting