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Asphalt pavements experience damage due to traffic loading under various environmental conditions . Damage can be caused by viscopl
microcracks , fracture due to fatigue cracking , or fracture due to thermal cracking . Asphalt pavements have the capability to remedi
s damage depending on binder surface and rheological properties , filler surface properties , and length of rest periods .
Asphalt mastic (asphalt and fine aggregates ) properties play an important role in controlling damage and healing . This dissertation
development of a comprehensive methodology to characterize damage and healing in asphalt mastics and mixtures . The methodology reli
ctive imaging techniques (X -ray CT ) , principles of continuum damage mechanics , and principles of micromechanics . The X -ray CT yield
meter that quantifies the percentage of cracks and air voids in a specimen . The continuum damage model parameters are derived from
p between applied stress and pseudo strain . The micromechanics model relates the damaged mastic modulus to a reference undamaged mo
ationship is a function of internal structure properties (void size , film thickness , and percentage of voids ) , binder modulus , aggr
and bond energy between binder and aggregates . The internal structure parameters are all obtained using X -ray CT and correlated .
The developed methodology was used to characterize damage in asphalt mastic and mixture specimens tested using the Dynamic Mechanic
A ) and dynamic creep test . The damage parameter measured using X -ray CT correlated very well with the predictions of the continuum
ics models . All damage parameters were able to reflect the accumulation of damage under cyclic loading and were also able to captur
of moisture conditioning on damage . Although this dissertation focused on fatigue cracking at room temperatures , the methodology d
used to assess damage due to different mechanisms such as permanent deformation and low temperature cracking . |
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