Characterization of Alaskan Hot-Mix Asphalt containing Reclaimed Asphalt Pavement Material

In order to properly characterize Alaskan HMA materials containing RAP, this study evaluated properties of 3 asphalt binders typically used in Alaska, PG 52-28, PG 52-40, and PG 58-34, and 11 HMA mixtures containing up to 35% RAP that were either produced in the lab or collected from existing paving projects in Alaska. Various binder and mixture engineering properties were determined, including true high binder grades, complex modulus (|G*|), and phase angle (δ) at high performance temperatures, MSCR recovery rate and compliance, BBR stiffness and m-value, DTT failure stress and strain for binders, and dynamic modulus, flow number, IDT creep stiffness and strength for mixtures. Binder cracking temperatures were determined through Thermal Stress Analysis Routine (TSAR) software along with BBR and DTT data. Mixture cracking temperatures were determined with IDT creep stiffness and strength data. It was found that rutting may not be a concern with Alaskan RAP mix, while low-temperature cracking concerns may still exist in RAP mix in Alaska. A savings of $13.3/ton was estimated for a 25% RAP mix, with consideration of Alaskan situations. Many recommendations for future RAP practice and research are recommended based on testing results and cost analysis.Alaska Department of Transportation Statewide Research Offic

Performance of TenCate Paving Interlayers in Asphalt Concrete Pavements

As a continued effort of a previously completed project entitled “Performance of TenCate Mirafi PGM-G4 Interlayer-Reinforced Asphalt Pavements in Alaska,” this project evaluated two newly modified paving interlayers (TruPave and Mirapave) through overlay, dynamic modulus tests and low-temperature performance tests. A field survey was conducted to further evaluate the performance of three paving interlayers (G4, G50/50, and G100/100) applied to field sections constructed in May 2013 at Milepost 148–156 Richardson Highway in Alaska. Overlay test results indicate that asphalt concrete (AC) with paving interlayers (TruPave and Mirapave) shows lower reduction in peak load, suggesting better cracking resistance. The dynamic modulus measurement of AC with paving interlayers reveals more rational results from the IDT mode test than the AMPT method due to similar stress conditions in the paving interlayer. With paving interlayers, the temperature sensitivity and cracking potential of AC material were reduced according to the results from the IDT creep test. Field survey results confirm that all sections reinforced with paving interlayers (G4, G50/50, and G100/100) had better cracking resistance than the control section.TenCate Geosynthetics North Americ

Effective action approach to the p-band Mott insulator and superfluid transition

Motivated by the recent experiment on p-orbital band bosons in optical lattices, we study theoretically the quantum phases of Mott insulator and superfluidity in two-dimensions. The system features a novel superfluid phase with transversely staggered orbital current at weak interaction, and a Mott insulator phase with antiferro-orbital order at strong coupling and commensurate filling. We go beyond mean field theory and derive from a microscopic model an effective action that is capable of describing both the p-band Mott insulating and superfluid phases in strong coupling. We further calculate the excitation spectra near the quantum critical point and find two gapless modes away from the tip of the Mott lobe but four gapless modes at the tip. Our effective theory reveals how the phase coherence peak builds up in the Mott regime when approaching the critical point. We also discuss the finite temperature phase transition of p-band superfluidity.Comment: 9+epsilon pages, 7 figures, one appendix added, accepted by Phys. Rev.