Evaluation of Cracking Resistance in Alaskan Asphalt Pavement with Paving Interlayers

Paving interlayers have been used in asphalt concrete (AC) overlays in a variety of design and construction situations for more than three decades. In cold regions such as Alaska and other northern states, AC pavements are more prone to distresses caused by climatic extremes; therefore, additional requirements should be satisfied when an interlayer is selected for a specific paving job. Although paving interlayers have been continuously improved for better performance, laboratory evaluation and performance data are still needed to verify the feasibility of using the existing and some newly developed paving interlayers in cold regions, especially for their cracking resistance. This paper presents a study to experimentally evaluate the cracking resistance of asphalt mixture reinforced with selected paving interlayers that are added as an entire layer and/or as interlayer strip. Laboratory tests included dynamic modulus, overlay, and direct tension tests conducted on asphalt mixture specimens by an asphalt mixture performance tester (AMPT). Pavement structural analysis and finite-element method (FEM) analysis were further performed to simulate and evaluate the performance of different paving interlayer-reinforced AC layers in the field. The laboratory testing results identified the high potentials of specimens reinforced by an entire layer or a strip of selected paving interlayers in improving pavement’s reflective cracking resistance. The interlayer strip was found capable of hindering the propagation of cracks and changing the path of crack development. The bonding between the interlayer and asphalt mixture may largely affect the effectiveness of the interlayer for crack resistance. Both pavement structural analysis and FEM simulation identified the benefits of using the selected paving interlayers.