The main goal of this project was to develop a simplified method that can be augmented with the Superpave mix design system so that ITD can implement it in asphalt mix design in Idaho.
The Superpave mix design system was released by the Strategic Highway Research Program (SHRP) in 1992 as a volumetric-based design method. State DOTs including ITD needed performance measures that could be used in addition to the volumetric procedure. SHRP performance testing methods were complex and were not ready to be adapted by DOTs. Therefore, the focus of this project was to develop a testing procedure that can be used to judge the mix quality during the mix design stage.
Develop Superpave trial mixes that have potential to be used in the state of Idaho.
Study the relationship between the gyratory compaction curve characteristics and permanent deformation (rutting) in pavements from WesTrack and other states. Develop compaction parameters that can be related to performance. Verify the developed relationship by the Idaho Hveen mixes (H1 and H2) developed in Task
Assess the sensitivity of the proposed compaction parameters to mix performance variation.
Conduct gyratory compaction in Idaho mixes (c1, C2, F1 and F2) and measure the parameters, which are to be developed from Tasks 2 and 3.
Perform image analysis techniques as well as energy calculations on samples from WesTrack and/or other states to identify regions in the densification curves that correspond to construction and traffic loading. This will assist in linking compaction parameters and aggregate structures to pavement performance.
Establish performance criteria based on the developed compaction-performance relationship to be developed in Task 5.
Prepare a report to document research findings and recommendations for Superpave mix design and construction in the state of Idaho.