Micromechanical Analysis on Viscoelasticity of Asphalt Mixtures

Mori-Tanaka　equivalent　inclusion　micromechanics　theory　was　employed　to　investigate　the　viscoelasticity　of　asphalt　mixture　Asphalt　mixture　was　regarded　as　composites　which　treated　coarse　aggregate　as　a　rigid　inclusion　and　the　mixture　of　fine　aggregate,filler　and　binder　as　viscoelastic　matrix　The　constitutive　relations　of　coarse　aggregate　inclusion　and　fine　aggregate-filler-binder　matrix　were　converted　into　elastic　problems　by　Laplace　transformation　Then　the　Mori-Tanaka　equivalent　inclusion　and　average　theory　were　used　to　deduce　the　viscoelastic　performance　of　asphalt　mixture　based　on　that　of　asphalt　mortar　in　Laplace　space　The　result　shows　that　(1)　coarse　aggregate　inclusion　can　enhancethe　viscoelastic　performance　of　fine　aggregate?filler?binder　matrix　and　viscoelastic　constitutive　relation　of　asphalt　mixtures　can　be　expressed　as　the　product　of　an　enhancement　coefficient　of　coarse　aggregate　and　the　viscoelastic　constitutive　relation　of　fine　aggregate?filler?binder　matrix;　(2)　the　viscoelasticity　of　the　complex　asphalt　mixture　can　be　predicted　from　the　viscoelasticity　of　the　homogeneous　fine　aggregate?filler?binder　matrix　by　using　the　nhancement　coefficient;　(3)　the　enhancement　coefficient　is　higher　than　10　and　it　rises　with　increasing　of　coarse　aggregates'　volumetric　fraction　or　Poisson's　ratio　of　fine　aggregate-filler-binder　matrix　but　the　effect　of　the　former　is　more　important　than　that　of　the　latter