Road aggregates in the Whanganui and Taranaki regions are generally softer than those used elsewhere in New Zealand. However the costs of importing premium quality aggregate (e.g. that which complies with TNZ M/4 specification) is prohibitive. Instead, local practitioners have utilised local materials with success.
The report identifies the engineering properties of three principal rock types used in these regions and describes how aggregate production can be controlled, particularly by the use of the particle size distribution graph. It also provides methods for the control of pavement construction and describes some special techniques required to ensure long-term stability of the pavement.
Keywords: Road aggregates, roads, Whanganui, Taranaki, non-standard aggregate, shell rock, aggregate