| The main objective of this thesis is to investigate the behaviour of asphalt concrete mixes under the effect of a forced angular displacement on its surface, as prescribed by a new testing facility. The facility was developed at Carleton University to evaluate the in-situ shear properties of the asphalt concrete mixes. A theoretical, numerical and experimental research program was planned and executed to achieve the research objectives.; The theoretical investigation included studying the Reissner Sagoci problem of applying a forced angular displacement to the surface of a half space, while the analytical phase was completed using a three dimensional, viscoelastic Finite Element Model (FEM) to study the effect of the different variables, such as the strain rate, on the shear stiffness evaluated during in-situ testing. The experimental investigation included in-situ testing on Carleton University campus and at an LTPP test site near Petawawa, Ontario, in addition to laboratory testing of core samples recovered from these sections. The testing program was planned to evaluate the characterization of the in-situ asphalt concrete mixes using the newly developed facility, versus the laboratory characterization using the resilient modulus testing and torsion testing. Furthermore, the effect of the actual strain rate on the in-situ testing results was investigated.; The research showed that the viscoelastic material properties and the actual strain rate during testing affect the field measurements. The thesis provided a number of significant enhancements to the developed InSiSST facility in terms of the data interpretation and analysis, with the most significant contribution of introducing a framework relating the in-situ shear stiffness of the asphalt concrete mixes to rutting in the asphalt concrete pavements. |
