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Polymer-modified asphalts are used in Alaska to address problems with rutting, cracking, and premature aging. This usage raises two important issues—the improvement of the pavement performance with polymer modification while maintaining the ability to properly place and compact polymer-modified mixes. This study addresses both issues. Base asphalts and polymer-modified binders were analyzed for storage stability, compatibility, and consistency using traditional and Superpave tests. Thermal stress restrained specimen tests and Georgia wheel rutting tests were conducted for asphalt-aggregate mixtures. The test results indicate that polymer-modified asphalts should always be an end result of an extensive product development program. The premanufactured binders had the best performance and workability. The polymer modification improved the performance of all base asphalts in several polymer-asphalt combinations. Some binders smoked excessively during mixing, which warrants further research. A storage stability test should be added to specifications or the contractor should address the storage stability with techniques such as tank circulation. On the basis of the test results, the Superpave PG grading needs to be adjusted for polymer-modified asphalts. [ABSTRACT FROM AUTHOR]

Elastic properties of bitumen reservoir change dramatically during thermal production, due to varying temperature and pressure conditions, which affect both the pore fluid and the rock frame. The effect of bitumen on the elastic properties of bitumen sands is widely studied, while the frame effect is commonly ignored. The influence of frame under different pressure and temperature conditions is investigated through laboratory measurements. Natural and artificial samples are compared to investigate the role of rock frame in their elastic properties. Samples with the same bitumen but different porosities are also compared, which reveals that the distinctions between the samples vary with temperature. Theoretical models are also applied to inspect the influence of rock frame, indicating the weak frame. In the end, two samples from Alaska and Alberta are compared, justifying the roles of bitumen and rock frame during the heating process. Our results reveal that rock frame of bitumen sands is quite loose, which may even damage during the heating process; and its influence on the rock elastic property is temperature dependent: at low temperature, its influence is insignificant, while at high temperature, its contribution is more important. These results suggest that for seismic monitoring of bitumen reservoir production, we should emphasize the temperature effect at the early stage and pay more attention to the pressure effect at the later stage of thermal production. • Artificial samples have similar acoustic velocities as natural samples. • The contribution of frame to the moduli of the rock is small at low temperature. • The influence of frame on the rock moduli varies with temperature. • The bitumen sands' frame is loose, and most grains are suspended with only a few contacts. • The influence of frame on the rock moduli increases with temperature. [ABSTRACT FROM AUTHOR]