Comparison of Conventional, Polymer, and Rubber Asphalt Mixtures Using Viscoelastic Continuum Damage Model

In this study, a laboratory experimental program was conducted to compare the
material properties and fatigue performance characteristics for reference, polymer-modified
and rubber-modified gap graded mixtures. These mixtures were placed on E18 highway
between the interchanges Järva Krog and Bergshamra in the Stockholm area of Sweden. The
advanced material characterization tests included: dynamic (complex) modulus for stiffness
evaluation and the uniaxial tension-compression for fatigue assessment. The data was used
to compare the performance of the rubber-modified gap graded mixture to the reference and
the polymer-modified gap mixtures using the viscoelastic continuum damage (VECD)
approach. Different researchers have successfully applied the VECD model to describe the
fatigue behavior of asphalt concrete mixtures. The damage characteristic (C-S) curves were
established for each of the three mixtures. The fatigue behavior for the three mixtures was
ranked based on the C-S curve results and the rubber-modified mixture showed the best
fatigue damage resistance followed by the polymer-modified mixture and the reference
mixture. The VECD approach provides a more comprehensive analysis to evaluate fatigue
resistance compared to tradition fatigue evaluation using a number of cycles at a given
stiffness reduction.