Abstract

For decades, rubber-modified asphalt mixtures have been successfully used in asphalt pavements for their improved crack resistance in addition to environmental benefits. In 2012, Pennsylvania DOT constructed a test section of gap-graded, wet process rubber modified pavement adjacent to a typical dense graded surface mixture on Interstate 78. Both mixtures used warm-mix technology as a means to improve density and workability. The main objective of this paper is to evaluate the laboratory crack initiation and propagation performance of the two mixtures and draw conclusions on the cracking performance. The experimental testing program includes the dynamic modulus test to obtain stiffness and viscoelastic properties, uniaxial fatigue test using a viscoelastic continuum damage model for fatigue crack initiation, and the C* fracture test for crack propagation. Overall, the asphaltrubber mixture showed enhancement in cracking resistance compared to a typical surface course mixture used in the region.

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