Crack propagation in the cyclic semi-circular bending test

Results are presented to describe crack propagation response in conventional and polymer-modified asphalt mixtures. The fracture characteristics of eight mixtures containing increasing amounts of poly(styrene-butadiene-styrene) (SBS) co-polymer are investigated under cyclic semi-circular bending conditions. Analysis based on Schapery's correspondence principle enables the conversion of the Paris Law from its classic linear elastic domain to elasto-plastic analysis adopting a generalised J-integral approach. Creep compliance is one of the material's intrinsic properties determined in the study to aid in achieving the domain conversion. This is measured on small cylindrical samples of the studied mixtures using a dynamic shear rheometer within the linear viscoelastic range. Results, expressed in terms of Paris Law pseudo-constants, are used to gauge the material's resistance to crack propagation where no clear correlations are found to the degree of polymer modification. Crack propagation in a typical UK pavement construction is modelled using the classic Paris Law and J-integral approaches.