A REVIEW OF AGGREGATE RESEARCH IN NEW ZEALAND

Most New Zealand road pavements have been constructed from unbound granular aggregates covered by a thin surface seal. The correct engineering and economic use of these aggregates requires a knowledge of the factors which control their performance in a pavement. Research to identify the characteristics of an aggregate which control its performance has been carried out since 1969. In 1978 the Pavements Committee carried out a review of some twenty projects which involved roading aggregates. This review, carried out in terms of a theory of pavement performance, concluded that while aggregates may deteriorate to a certain extent as a result of mechanical degradation and weathering, it was unlikely that they ever reached a terminal condition. It was found that the origins of the rock and its weathering properties, the grading and the moisture content of the aggregate were the major factors which controlled performance (a). The number of the covering abstract of the conference is TRIS No. 368448. (TRRL)