The stabilisation of near-surface granular pavement materials is accepted practice in transportation maintenance and capital development projects in Australasia. Stabilisation in this context involves the mechanical introduction of reactive agents, including cement and foamed bitumen, into existing or manufactured granular materials, with or without existing seal inclusion.
Present-day design guides characterise stabilised granular materials as either modified or bound, depending primarily on the amount and type of reactive agent used in the stabilising process. Modified materials are modelled as unbound granular materials in a pavement.
Bound (cemented) materials are modelled as layers with tensile load-carrying capacity within the pavement. Cracking in the bound pavement layer is governed by 'fatigue relationships'.
This research has shown that stabilisation with smaller reactive agent contents (<3% by dry mass) can deliver materials that should be modelled as lightly bound, delivering cost-effective pavement solutions.
This research report describes the collection and interrogation of performance data from New Zealand road pavements that utilised stabilised granular materials. The research, carried out from December 2009 to August 2011, compared actual stabilised pavement performance with the expectations in published design guidelines. A conceptual pavement performance model for near-surface 'lightly bound' stabilised granular pavement layers that better matches observed pavement behaviour is proposed.